Co-reporter:Yubin Ding, Wei-Hong Zhu, and Yongshu Xie
Chemical Reviews February 22, 2017 Volume 117(Issue 4) pp:
Publication Date(Web):April 14, 2016
DOI:10.1021/acs.chemrev.6b00021
Sensing of metal ions and anions is of great importance because of their widespread distribution in environmental systems and biological processes. Colorimetric and fluorescent chemosensors based on organic molecular species have been demonstrated to be effective for the detection of various ions and possess the significant advantages of low cost, high sensitivity, and convenient implementation. Of the available classes of organic molecules, porphyrin analogues possess inherently many advantageous features, making them suitable for the design of ion chemosensors, with the targeted sensing behavior achieved and easily modulated based on their following characteristics: (1) NH moieties properly disposed for binding of anions through cooperative hydrogen-bonding interactions; (2) multiple pyrrolic N atoms or other heteroatoms for selectively chelating metal ions; (3) variability of macrocycle size and peripheral substitution for modulation of ion selectivity and sensitivity; and (4) tunable near-infrared emission and good biocompatibility. In this Review, design strategies, sensing mechanisms, and sensing performance of ion chemosensors based on porphyrin analogues are described by use of extensive examples. Ion chemosensors based on normal porphyrins and linear oligopyrroles are also briefly described. This Review provides valuable information for researchers of related areas and thus may inspire the development of more practical and effective approaches for designing high-performance ion chemosensors based on porphyrin analogues and other relevant compounds.
Co-reporter:Jiahui Kong, Qizhao Li, Minzhi Li, Xin Li, Xu Liang, Weihua Zhu, Hans Ågren, Yongshu Xie
Dyes and Pigments 2017 Volume 137() pp:430-436
Publication Date(Web):February 2017
DOI:10.1016/j.dyepig.2016.10.038
•Convenient syntheses of the unsubstituted and di-α-methoxy substitued bidipyrrin.•Efficient syntheses of the bidipyrrin Ni(II) and Zn(II) complexes.•Unique M2L2 type helical Zn(II) coordination structures.•The conformations and Zn⋯Zn distances modulated by the methoxy moieties.A bidipyrrin nickel complex was synthesized in a high yield by oxidatively coupling between the ligands in the corresponding 2:1 (L:M) type of dipyrrin nickel complex, and further demetallation afforded the free bidipyrrin ligand. Interestingly, when treating the bidipyrrin nickel complex or the free bidipyrrin with FeCl3 in CH2Cl2/MeOH, the symmetric di-α-methoxy bidipyrrin could be synthesized in a high yield, with two methoxy groups attached to the terminal pyrrolic α-positions. Moreover, the coordination of the unsubstituted and disubstituted bidipyrrins with Zn(OAc)2·2H2O afforded two similar M2L2 type of bidipyrrin helical complexes with different ligand conformations and different Zn⋯Zn distances of 5.353 and 3.357 Å, respectively. The difference in the conformations may be related to the electrostatic repulsions between the methoxy substituents. These results indicate that the dyes based on helical bidipyrrin zinc complexes with tunable structures and photophysical properties may be developed simply by modulating the terminal α-substituents.Unsubstituted and di-α-methoxy- bidipyrrins were synthesized and used for coordination with Zn(II) to afford the corresponding M2L2 type helical complexes with different ligand conformations and obviously different Zn⋯Zn distances.
Co-reporter:Heli Song, Xin Li, Hans Ågren, Yongshu Xie
Dyes and Pigments 2017 Volume 137() pp:421-429
Publication Date(Web):February 2017
DOI:10.1016/j.dyepig.2016.10.041
•Syntheses of branched and linear alkoxy chains-wrapped push-pull porphyrins.•Broadening of the absorption range by the additional benzothiadiazole group.•Better suppression of dye-aggregation and charge recombination by branched chains.•An achieved power conversion efficiency of 9.62%.Four alkoxy-wrapped push-pull porphyrin dyes containing the phenothiazine derived donor and the ethynylbenzoic acid acceptor have been designed, synthesized and used as sensitizers for fabricating efficient dye-sensitized solar cells (DSSCs). Branched or linear alkoxy chains were introduced to the ortho-positions of the meso-phenyl moieties to suppress the dye aggregation and charge recombination. The effect of alkoxy chains were investigated in the absence and presence of an additional electron-withdrawing benzothiadiazole unit. In the former cases, almost identical photovoltaic efficiencies of ∼8.3% were achieved for both the branched and the linear alkoxy chains, while in the latter cases, the planar benzothiadiazole unit induces serious dye aggregation and charge recombination, resulting in lower efficiencies of 6.46% and 7.50% for the linear and branched chains, respectively, even though broader absorption was achieved. The relatively higher efficiency achieved for the dyes with branched chains may be related to the better effect of suppressing the dye aggregation and charge recombination. Furthermore, the coadsorption approach was employed, and a highest efficiency of 9.62% was achieved for the dye that features branched chains and the benzothiadiazole unit. These results compose a novel approach for developing efficient DSSCs by combining the coadsorbent with a porphyrin dye containing both the additional benzothiadiazole acceptor and branched alkoxy chains.
Co-reporter:Lulu Bu, Junqin Chen, Xiaodong Wei, Xin Li, Hans Ågren, Yongshu Xie
Dyes and Pigments 2017 Volume 136() pp:724-731
Publication Date(Web):January 2017
DOI:10.1016/j.dyepig.2016.09.032
•Combination of AIE and ICT for designing fluorescence turn-on probes.•The non-fluorescent state as a good starting point for PL “turn-on” probes.•A novel near-infrared (NIR) fluorescent biothiol probe.•Applicable for detecting the biothiols in aqueous systems and living cells.A combination of aggregation-induced emission and intramolecular charge transfer was achieved by using a triphenylamine analogue and a dicyanovinyl moiety as the electron donating and accepting units, respectively. Hence, we designed and synthesized a probe with a D-π-A framework as a near-infrared fluorescence turn-on probe for biothiols (cysteine and homocysteine). Owing to the remarkable intramolecular charge transfer effect as well as intramolecular rotations associated with the donor moiety, the probe exhibits extremely weak fluorescence, which becomes a good starting point for developing fluorescence “turn-on” probes. Upon reaction with cysteine or homocysteine utilizing the dicyanovinyl moiety, the intramolecular charge transfer character was weakened, and the reacting products were observed to aggregate in aqueous solutions, resulting in the aggregation-induced emission effect with red fluorescence at 651 and 656 nm, respectively. Hence, the probe could be used as a fluorescence “turn-on” sensor for cysteine and homocysteine, with the sensing time of less than 4 min and the detection limits of 8.4 μM and 5.7 μM towards cysteine and homocysteine, respectively. The probe could distinguish cysteine and homocysteine from glutathione. The sensing mechanism was systematically investigated by employing high resolution mass spectrometry, 1H NMR and density functional theory calculations as well as checking the solvent viscosity dependent fluorescence, and thus the nucleophilic addition products, the intramolecular charge transfer character, and the aggregation-induced emission behaviour were clearly elucidated. It is noteworthy that the low cytotoxicity, the intrinsic aggregation-induced emission nature and near-infrared emissions enable the application of the probe in living cell imaging.Figure optionsDownload full-size imageDownload as PowerPoint slide
Co-reporter:Xiaodong Wei, Lulu Bu, Xin Li, Hans Ågren, Yongshu Xie
Dyes and Pigments 2017 Volume 136() pp:480-487
Publication Date(Web):January 2017
DOI:10.1016/j.dyepig.2016.08.069
•Four aldehydes obtained from simple formylation of diphenylaminoantharacene.•Emissions modulated by varying the numbers and positions of the formyl groups.•Synthesis of the corresponding BODIPYs with tunable emissions.•Full color emissions achieved by modulating intramolecular charge transfer.From the simple one-pot Vilsmeier formylation of 9-diphenylaminoanthracence, mono-, di- and tri-formyl products were successfully synthesized and the yields for the individual products can be optimized by varying the equivalents of the Vilsmeier reagent and changing the reaction temperature. The four obtained aldehydes exhibit distinct optical properties, with the emission maxima varying in a large wavelength range of 455–593 nm, despite their similar structures. The intramolecular charge transfer effect can be effectively modulated by varying the numbers and positions of the formyl groups, resulting in the observed distinct optical properties. Based on the aldehydes, the corresponding boron-dipyrromethenes were also synthesized. Similarly, the intramolecular charge transfer effect and the optical properties can be effectively modulated by the numbers and positions of the boron-dipyrromethene moieties. To further modulate the intramolecular charge transfer effect and red shift the emission, the dimethoxy-substituted 9-diphenylaminoanthracence was also used for synthesizing the corresponding aldehyde and boron-dipyrromethene. Thus, full color emissions within the wavelength range of 455–704 nm were successfully achieved based on modulating the intramolecular charge transfer.Formyl and boron-dipyrromethene groups were attached to diphenylaminoanthracenes, achieving tunable ICT and full-color emissions.
Co-reporter:Jiahui Kong, Jiewei Shao, Chengjie Li, Dongdong Qi, Minzhi Li, Xu Liang, Weihua Zhu, Jianzhuang Jiang, and Yongshu Xie
Organic Letters 2017 Volume 19(Issue 3) pp:
Publication Date(Web):January 23, 2017
DOI:10.1021/acs.orglett.6b03816
By the acid-catalyzed [2 + 2] condensation, an unprecedented neo-N-confused phlorin (neo-NCphlorin 1) was successfully synthesized. By treating 1 with N-chlorosuccinimide, the corresponding chloro-substituted neo-NCphlorin (1-Cl) was obtained. The oxidization of 1 with FeCl3 afforded the neo-N-confused phlorinone (neo-NCphlorinone 2), which bears a relatively coplanar conformation, different from the highly distorted ones observed for 1 and 1-Cl. Notably, 2 shows striking long-wavelength absorption beyond 1300 nm upon addition of TBAF.
Co-reporter:Jun Pan, Heli Song, Cheng Lian, Honglai Liu, Yongshu Xie
Dyes and Pigments 2017 Volume 140(Volume 140) pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.dyepig.2017.01.027
•Extension of absorption spectra by additional donor and acceptor moieties.•Co-sensitization strategy using the cocktail solutions of the two porphyrin dyes.•An achieved high power conversion efficiency of 8.60%.With the purpose to develop efficient dye-sensitized solar cells (DSSCs), a series of push-pull porphyrin dyes have been designed and optimized by introducing additional electron-donating diphenylamino and electron-withdrawing benzothiadiazole moieties. Electrochemical, photophysical and photovoltaic investigations indicate that the introduction of additional donors and acceptors can effectively extend the absorption spectra, resulting in better sunlight harvesting. However, the HOMO levels of the dyes are elevated by the additional donors, resulting in decreased driving forces for dye regeneration and decreased cell efficiencies. Upon coadsorption with 5 mM chenodeoxycholic acid (CDCA), the cell efficiencies can be elevated from 1.37% - 5.01% to 1.70% - 6.97%. Furthermore, based on the subtle absorption characteristics of the porphyrin dyes, we delicately designed a cocktail co-sensitization strategy using the solutions containing two of the porphyrin dyes as well as CDCA. Finally, a high photovoltaic efficiency of 8.6% was successfully achieved at an optimized molar ratio of 10:1 for the two porphyrin dyes.Download high-res image (210KB)Download full-size image
Co-reporter:Xiaodong Wei, Qing Wang, Weiqiang Tang, Shuangliang Zhao, Yongshu Xie
Dyes and Pigments 2017 Volume 140(Volume 140) pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.dyepig.2017.01.064
•Strongly coordinating pyridyl moieties introduced to dipyrrin platforms.•Distinct Zn2+ sensing behavior modulated by different substituents.•Impressive detection limits of 9.8 and 6.3 nM.•Crystal structure of an interesting tetranuclear Zn2+ complex.The selective and sensitive detection of zinc ions has been an important research topic because of the vital role played by zinc ions in numerous physiological activities, and fluorescent probes have emerged as effective and powerful tools for zinc detection because of their simplicity andcereal-time monitoring nature. In this work, with the purpose to improve the binding affinities and sensitivities of dipyrrin based fluorescent Zn2+ probes, strongly coordinating pyridyl moieties were introduced into dipyrrins. Aroylation of 5-pentafluorophenyl and 5-unsubstituted dipyrromethanes with picolinoyl chloride afforded two corresponding dipicolinoyl dipyrromethanes, which were further oxidized with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to afford the expected 5-pentafluorophenyl-substituted dipicolinoyl dipyrrin and a unique unexpected dipicolinoyl dipyrrolyl ketone, respectively. Both of these compounds exhibited noticeable fluorescence “turn-on” responses specifically to Zn2+ over other metal cations, with fluorescence enhancements of 87 fold and 119 fold, respectively. However, because of the different substituents at the 5 positions and the different conjugation frameworks, distinct Zn2+ sensing behavior was observed. For the 5-pentafluorophenyl-substituted dipicolinoyl dipyrrin, the sensing of Zn2+ induced a color change from light orange to pink accompanied with enhanced red fluorescence. Whereas, the sensing of Zn2+ by the dipicolinoyl dipyrrolyl ketone induced the color change from nearly colorless to bright yellow and enhanced green fluorescence. Based on high binding affinities and the dramatic spectral responses, both of the probes exhibit high sensitivities towards Zn2+ with detection limits of 9.8 nM and 6.3 nM, respectively. In addition, fast responses within 10 s and wide applicable pH ranges are indicative of their potential applications as promising zinc probes. Finally, the 5-pentafluorophenyl dipicolinoyl dipyrrin was successfully applied to cell imaging in Hela cells, demonstrating its practical applicability. It is noteworthy that the single crystal structure of a Zn2+ complex of the dipicolinoyl dipyrrolyl ketone was successfully analyzed by X-ray diffraction, which revealed an interesting tetranuclear Zn2+ coordination structure. These results provide further insights into the design of highly sensitive Zn2+ probes by introducing pyridyl moieties into dipyrrin platforms.Download high-res image (226KB)Download full-size image
Co-reporter:Xiaodong Wei;Lulu Bu;Weiqiang Tang;Shuangliang Zhao
Science China Chemistry 2017 Volume 60( Issue 9) pp:1212-1218
Publication Date(Web):03 July 2017
DOI:10.1007/s11426-017-9062-2
Two fluorescence “turn-on” Zn2+ probes were developed by introducing an anthracenyl fluorophore through the linkage of a diphenylamino moiety at the 5-position of a dipyrrin moiety. Thus, two compounds with weak fluorescence were designed, synthesized, and employed as CHEF (chelation enhanced fluorescence) type fluorescence “turn-on” Zn2+ probes, which exhibit dramatic fluorescence enhancement upon addition of Zn2+, showing high sensitivities and impressive detection limits of 13 and 12 nM, respectively, better than their analogues containing simple aryl substituents at the 5 positions of a di- or tripyrrin moiety. In addition, both of the probes exhibit good selectivity, short response time of less than 10 s and wide applicable pH ranges. Furthermore, the weak fluorescence nature of the probes was rationalized based on viscosity dependence measurements and theoretical calculations. These results provide further insight into the development of selective and sensitive zinc probes.
Co-reporter:Kai Zhang, Mathew Savage, Xin Li, Yu Jiang, Masatoshi Ishida, Koki Mitsuno, Satoru Karasawa, Tatsuhisa Kato, Weihua Zhu, Sihai Yang, Hiroyuki Furuta and Yongshu Xie
Chemical Communications 2016 vol. 52(Issue 29) pp:5148-5151
Publication Date(Web):10 Mar 2016
DOI:10.1039/C6CC00707D
A rational and effective approach for synthesizing linear π-conjugated hexa-, hepta- and octapyrrins through the regioselective oxidative coupling of monoacylated tripyrrane and bilane is described. Depending upon the numbers of pyrrolic units, the geometry and properties of bis-copper(II) complexes could be systematically modulated.
Co-reporter:Jiahui Kong, Qiong Zhang, Mathew Savage, Minzhi Li, Xin Li, Sihai Yang, Xu Liang, Weihua Zhu, Hans Ågren, and Yongshu Xie
Organic Letters 2016 Volume 18(Issue 19) pp:5046-5049
Publication Date(Web):September 22, 2016
DOI:10.1021/acs.orglett.6b02495
By oxidation of an alternately N-confused bilane in CH2Cl2, a C–N fused tetrapyrrin was synthesized that bears a 5.5.5-tricyclic ring generated from an intramolecular C–N linkage. When CH3CN was used as the reaction medium, a multiply C–N-fused octapyrrolic dimer was also obtained that contained two 5.5.5.7.5-pentacyclic moieties and a bipyrrole unit generated from the intramolecular C–N linkage and intermolecular C–C linkage, respectively. This could be coordinated with Ni(acac)2 to afford a mixed-ligand complex.
Co-reporter:Yubin Ding, Yunyu Tang, Weihong Zhu and Yongshu Xie
Chemical Society Reviews 2015 vol. 44(Issue 5) pp:1101-1112
Publication Date(Web):22 Jan 2015
DOI:10.1039/C4CS00436A
Metal ions and anions play important roles in many industrial and biochemical processes, and thus it is highly desired to detect them in the relevant systems. Small organic molecule based sensors for selective and sensitive detection of target ions show the advantages of low cost, high sensitivity and convenient implementation. In this area, pyrrole has incomparable advantages. It can be easily incorporated into linear and macrocyclic conjugated structures such as dipyrrins, porphyrins, and N-confused porphyrins, which may utilize the imino N and amino NH moieties for binding metal ions and anions, respectively. In this tutorial review, we focus on representative examples to describe the design, syntheses, sensing mechanisms, and applications of the conjugated oligopyrroles. These compounds could be used as colorimetric or fluorescent ion probes, with the advantages of vivid colour and fluorescence changes, easy structural modification and functionalization, and tunable emission wavelengths. Compared with normal porphyrins, simple di- and tripyrrins, as well as some porphyrinoids are more suitable for designing fluorescence “turn-on” metal probes, because they may exhibit flexible confirmations, and metal coordination will improve the rigidity, resulting in vivid fluorescence enhancement. It is noteworthy that the oligopyrrolic moieties may simultaneously act as the binding unit as well as the reporting moiety, which simplifies the design and syntheses of the probes.
Co-reporter:Yongshu Xie; Yunyu Tang; Wenjun Wu; Yueqiang Wang; Jingchuan Liu; Xin Li; He Tian;Wei-Hong Zhu
Journal of the American Chemical Society 2015 Volume 137(Issue 44) pp:14055-14058
Publication Date(Web):October 22, 2015
DOI:10.1021/jacs.5b09665
Dye-sensitized solar cells (DSSCs) are promising for utilizing solar energy. To achieve high efficiencies, it is vital to synergistically improve the photocurrent (Jsc) and the photovoltage (Voc). In this respect, conjugation framework extension and cosensitization are effective for improving the absorption and the Jsc, which, however, is usually accompanied by undesirably decreased Voc. Herein, based on a rationally optimized porphyrin dye, we develop a targeted coadsorption/cosensitization approach for systematically improving the Voc from 645 to 727, 746, and 760 mV, with synergistical Jsc enhancement from 18.83 to 20.33 mA cm–2. Thus, the efficiency has been dramatically enhanced to 11.5%, which keeps the record for nonruthenium DSSCs using the I2/I3– electrolyte. These results compose an alternative approach for developing highly efficient DSSCs with relatively high Voc using traditional iodine electrolyte.
Co-reporter:Tiantian Wei, Xi Sun, Xin Li, Hans Ågren, and Yongshu Xie
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 39) pp:21956
Publication Date(Web):September 10, 2015
DOI:10.1021/acsami.5b06610
Cyanoacrylic and carboxyl groups have been developed as the most extensively used electron acceptor and anchoring group for the design of sensitizers for dye-sensitized solar cells. In terms of the photoelectric conversion efficiency, each of them has been demonstrated to be superior to the other one in certain cases. Herein, to further understand the effect of these two groups on cell efficiencies, a series of porphyrin sensitizers were designed and synthesized, with the acceptors systematically varied, and the effect of the neighboring ethynylene unit was also investigated. Compared with the sensitizer XW5 which contains a carboxyphenyl anchoring moiety directly linked to the meso-position of the porphyrin framework, the separate introduction of a strongly electron-withdrawing cyanoacrylic acid as the anchoring group or the insertion of an ethynylene unit can achieve broadened light absorption and IPCE response, resulting in higher Jsc and higher efficiency. Thus, compared with the efficiency of 4.77% for XW5, dyes XW1 and XW6 exhibit higher efficiencies of 7.09% and 5.92%, respectively. Simultaneous introduction of the cyanoacrylic acid and the ethynylene units into XW7 can further broaden light absorption and thus further improve the Jsc. However, XW7 exhibits the lowest Voc value, which is not only related to the floppy structure of the cyanoacrylic group but also related to the aggravated dye aggregation effect due to the extended framework. As a result, XW7 exhibits a relatively low efficiency of 5.75%. These results indicate that the combination of the ethynylene and cyanoacrylic groups is an unsuccessful approach. To address this problem, a cyano substituent was introduced to XW8 at the ortho position of the carboxyl group in the carboxyphenyl acceptor. Thus, XW8 exhibits the highest efficiency of 7.59% among these dyes. Further cosensitization of XW8 with XS3 dramatically improved the efficiency to 9.31%.Keywords: anchoring groups; cyano group; dye-sensitized solar cells; porphyrin; π-linkers
Co-reporter:Yunyu Tang, Yueqiang Wang, Xin Li, Hans Ågren, Wei-Hong Zhu, and Yongshu Xie
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 50) pp:27976
Publication Date(Web):November 26, 2015
DOI:10.1021/acsami.5b10624
Porphyrins are promising DSSC sensitizers due to their structural similarity to chlorophylls as well as their tunable strong absorption. Herein, a novel D−π–A porphyrin dye XW14 containing a strongly electron-donating triphenylamine moiety as the electron donor was designed and synthesized. To avoid undesirably decreased Voc caused by dye aggregation effect, two methoxy or hexyloxy chains were introduced to the para positions of the triphenylamine moiety to afford XW15 and XW16, respectively. To further extend the absorption to a longer wavelength, a benzothiadiazole unit was introduced as an auxiliary acceptor to furnish XW17. Compared with XW14, the introduction of additional methoxy or hexyloxy groups in XW15 and XW16 red-shift the onset wavelengths from 760 to 780 and 790 nm, respectively. More impressively, XW17 has a more extended π-conjugation framework, and thus, it exhibits a much broader IPCE spectrum with an extremely red-shifted onset wavelength of 830 nm, resulting in the highest Jsc (18.79 mA cm–2). On the other hand, the hexyloxy chains are favorable for suppressing the dye aggregation effect, and thus XW16 shows the highest Voc of 734 mV. As a result, XW16 and XW17 demonstrate photovoltaic efficiencies of 9.1 and 9.5%, respectively, higher than those of XW14 (8.6%) and XW15 (8.7%), and obviously higher than that of 7.94% for our previously reported dye, XW4. On the basis of optimized porphyrin dye XW17, we used a nonporphyrin dye with a high Voc and strong absorption around 500 nm (WS-5) as the cosensitizer to improve the Voc from 700 to 748 mV, with synergistical Jsc enhancement from 18.79 to 20.30 mA cm–2. Thus, the efficiency was dramatically enhanced to 10.9%, which is among the highest efficiencies obtained for the DSSCs based on traditional iodine electrolyte. In addition, the DSSCs based on XW17 + WS-5 exhibit good photostability, which is beneficial for practical applications.Keywords: cosensitization; dye; porphyrin; sensitizers; solar cells
Co-reporter:Kai Zhang, Junda Zhang, Xin Li, Rui Guo, Hans Ågren, Zhongping Ou, Masatoshi Ishida, Hiroyuki Furuta, and Yongshu Xie
Organic Letters 2015 Volume 17(Issue 19) pp:4806-4809
Publication Date(Web):September 14, 2015
DOI:10.1021/acs.orglett.5b02363
Novel neo-confused octaphyrin(1.1.1.1.1.1.1.0) (1) was synthesized by oxidative ring closure of an octapyrrane bearing two terminal “confused” pyrroles. Crystal structures of its Zn(II) and Cu(II) complexes (2 and 3) show a figure-of-eight conformation with unique mononuclear coordination structures. Photophysical data and theoretical calculations suggest that the neo-confused octaphyrin 1 is a 34π electron conjugated species showing nonaromaticity. Coordination of copper and zinc ions results in the further narrowing of the HOMO–LUMO gaps.
Co-reporter:Bin Chen, Lu Sun, Yong-Shu Xie
Chinese Chemical Letters 2015 Volume 26(Issue 7) pp:899-904
Publication Date(Web):July 2015
DOI:10.1016/j.cclet.2015.04.021
Porphyrin dyes have received great attention due to their excellent photovoltaic performance in dye-sensitized solar cells (DSSCs). In this work, dyes XC1–XC3 were synthesized by introducing various numbers of bis(4-methoxyphenyl)amino and p-hexyloxyphenyl groups to porphyrin meso-positions. The XC1 molecule contains two p-hexyloxyphenyl groups, and its DSSCs showed the power conversion efficiency of 4.81%. For XC2 and XC3, the replacement of p-hexyloxyphenyl with diphenylamino groups can effectively enhance the light harvesting around 500 nm. However, the highest occupied molecular orbitals (HOMOs) were elevated too much, which suppressed the dye regeneration processes, leading to low cell efficiencies of 2.51% and 1.27% for XC2, and XC3, respectively. To further improve the cell performance, an anthracene derivative C1 was used as the cosensitizer for XC1, which increased both the Jsc and Voc values, with an improved efficiency of 5.75%.The photovoltaic behavior can be rationally modulated by introduction of various electron donors into the porphyrin framework as well as cosensitization. The power conversion efficiency of 5.75% can be achieved for the dye-sensitized solar cells.
Co-reporter:Kai Zhang, Pingchun Wei, Xin Li, Hans Ågren, and Yongshu Xie
Organic Letters 2014 Volume 16(Issue 24) pp:6354-6357
Publication Date(Web):December 8, 2014
DOI:10.1021/ol503132r
A C6F5-substituted hexapyrrane (1) was synthesized in one step. Oxidative cyclization of 1 with DDQ afforded a phlorin–dipyrrin conjugate (2), and subsequent FeCl3-assisted oxidative cleavage of 2 afforded a terminally di-α-methoxy substituted hexapyrrin (3). On the other hand, oxidation of 1 with FeCl3 afforded 3, a hexapyrrinone Fe3+ complex (4), and a hexaphyrin (1,1,1,1,1,0) (5). These results indicate that the oxidation of hexapyrranes may be developed as an effective approach for the syntheses of novel linear and macrocyclic hexapyrroles.
Co-reporter:Xi Sun, Yueqiang Wang, Xin Li, Hans Ågren, Weihong Zhu, He Tian and Yongshu Xie
Chemical Communications 2014 vol. 50(Issue 98) pp:15609-15612
Publication Date(Web):22 Oct 2014
DOI:10.1039/C4CC07963A
XS1–XS3 have been synthesized by introducing an auxiliary acceptor into D–π–A dyes for simultaneous filling up of both absorption valleys of porphyrin dyes at around 550 and 380 nm. Thus, panchromatic DSSCs with the highest efficiency of 10.75% were achieved by cosensitization. This work provides a strategy for designing cosensitizers for porphyrin dyes.
Co-reporter:Quanzheng Zha, Xing Rui, Tiantian Wei and Yongshu Xie
CrystEngComm 2014 vol. 16(Issue 32) pp:7371-7384
Publication Date(Web):06 Jun 2014
DOI:10.1039/C4CE00854E
Porphyrin-based coordination polymers (PCPs) have been investigated for a variety of applications including hydrogen storage, molecular sorption and sensing, photonics, and heterogeneous catalysis. The design and construction of functional PCPs with intriguing structures and promising properties are significant challenges for porphyrin and coordination chemists accompanying huge opportunities. This highlight is focused on recent advances in the design strategies for PCPs, which are summarized as follows: i) introduction of novel multimetal nodes such as multinuclear lanthanides and Zr6 clusters or insertion of active metal ions into the porphyrin core; ii) design and syntheses of novel porphyrinic ligands with multi-carboxyl or pyridyl coordination sites; iii) combination with inorganic polyoxometalates; and iv) encapsulation of porphyrins in cages and post-synthetic modification.
Co-reporter:Caixia Ding, Xing Rui, Cheng Wang and Yongshu Xie
CrystEngComm 2014 vol. 16(Issue 6) pp:1010-1019
Publication Date(Web):20 Nov 2013
DOI:10.1039/C3CE42147C
In this work, we designed and synthesized a novel ligand, N,N-bis(6-(1H-pyrazolyl)2-pyridyl)-N′,N′-bis(4-pyridyl)1,4-phenylenediamine (L). Coordination of d10 metals, Co(II) and Cu(II), with L generated eight novel coordination polymers [ZnLCl2]n (1), [ZnLBr2]n (2), [ZnLI2]n (3), [CdL2Cl2]n (4), [CdL2Br2]n (5), [CdLI2]n (6), {[CoL(SCN)](ClO4)}n·1.5nDMF·0.5nH2O (7) and {[Cu2L2(N3)]·3ClO4}n (8). Single-crystal X-ray diffraction analyses revealed that complexes 1–3 and 6 are isostructural. In these complexes, the ligand L utilizes its two pyridyl nitrogens of the 4,4′-dpa moiety to bridge metal ions, affording 1D zigzag chains, which are further linked by intermolecular C–H⋯π and hydrogen bond interactions to form 3D supramolecular structures. Complexes 4 and 5 have isostructural 1D double chain structures. In the d10 metal complexes 1–6, the potentially chelating bppa units of L are left non-coordinated in the “L” or “M” shaped conformation. In contrast, in complexes 7 and 8, the bppa units chelate the paramagnetic metal ions in the “U” shaped conformation. For complex 7, the bppa unit of L chelates a Co(II) atom, and a pyridyl nitrogen of the 4,4′-dpa unit bridges another Co(II) atom, thus affording a 1D chain structure. Similar to that observed in 7, each L ligand in complex 8 links two Cu(II) ions, and a μ1,3-azide further bridges two Cu(II) ions from neighbouring chains, affording a 2D undulated layer, which is interpenetrated by another such 2D sheet, forming a 2-fold interpenetrated structure. Based on the interesting structural results, the solid-state luminescent properties of complexes 1–6 were investigated, which revealed that the emission maximum wavelengths can be tuned in a large range of 372–486 nm.
Co-reporter:Tao Hong, Heli Song, Xin Li, Weibing Zhang and Yongshu Xie
RSC Advances 2014 vol. 4(Issue 12) pp:6133-6140
Publication Date(Web):09 Jan 2014
DOI:10.1039/C3RA47277A
The acylation of 2,2′-bipyrrole with pentafluorobenzoyl chloride in the presence of AlCl3 afforded six acylated products with rich α-, β-, β1-, α,α′-, α,β′-, and α,β1′-substitution modes for 1–6, respectively. Then, the α,α′-diacylated compound 4 was used to synthesize a prodigiosin derivative 9, which provides an alternative method for the syntheses of prodigiosin derivatives. Crystal structures of 1, 4 and 9 show interesting supramolecular dimers formed by multiple hydrogen bonds, O⋯π interactions, as well as π⋯π interactions. Interestingly, 9 shows fluorescence turn-on probing behavior towards Zn2+ both in DMF and in DMF–HEPES, with high sensitivity and selectivity. The detection limit for Zn2+ in DMF was calculated to be 1.1 × 10−8 M.
Co-reporter:Bin Chen, Xin Li, Wenjun Wu, Quanzheng Zha and Yongshu Xie
RSC Advances 2014 vol. 4(Issue 21) pp:10439-10449
Publication Date(Web):04 Feb 2014
DOI:10.1039/C3RA45791E
A novel trigeminal zinc porphyrin sensitizer (T) and two zinc porphyrin monomers (M1 and M2) were successfully designed and synthesized. The spectral, electrochemical, and photovoltaic properties of the porphyrin dyes were investigated. Compared with M1, the molecule of M2 has an additional aliphatic n-hexyloxyl chain at the meso-position of the porphyrin framework, and such a structure is favorable for the formation of a compact hydrophobic layer at the TiO2 surface and the retardation of the diffusion of I3− ions into the nanoporous TiO2 electrode, resulting in more effective suppression of the charge recombination process and a higher Voc. Meanwhile, M2 has larger IPCE values than those of M1, leading to the higher Jsc value. Thus, the DSSC devices based on M2 demonstrated a relatively high power conversion efficiency of 5.77%, with the Jsc, Voc and ff values of 13.93 mA cm−2, 732 mV, and 0.566, respectively. Even though dye T has the highest molar absorption coefficients and multiple binding moieties, the corresponding power conversion efficiency is 2.30%, which is lower than those for M1 and M2. These observations may be ascribed to the low efficiency of the electron injection process caused by the isolation of the LUMOs from the anchoring carboxyl groups in addition to the lowest adsorption amount.
Co-reporter:Yueqiang Wang, Lu Xu, Xiaodong Wei, Xin Li, Hans Ågren, Wenjun Wu and Yongshu Xie
New Journal of Chemistry 2014 vol. 38(Issue 7) pp:3227-3235
Publication Date(Web):08 May 2014
DOI:10.1039/C4NJ00651H
Four novel D–π–A porphyrin dyes (YQ1–YQ4) with 2-diphenylaminothiophene attached at the meso-position as the electron donor have been synthesized and used as the sensitizers for dye sensitized solar cells (DSSCs). 4-Ethynylbenzoic acid and 2-cyanoacrylic acid were incorporated as the anchoring moieties in YQ1, and YQ2–YQ4, respectively. Due to the extended conjugation size, the absorption spectra of YQ2–YQ4 showed Soret band maxima in the range of 447–468 nm, which is red shifted as compared to that of 446 nm for YQ1. Furthermore, in comparison with most reported porphyrin dyes with similar structures, YQ1–YQ4 demonstrate obviously red-shifted absorption maxima and broadened Soret bands, indicating that these porphyrin dyes may be developed as promising DSSC sensitizers. The electrochemical studies and DFT calculations indicated that all the four dyes were capable of serving as DSSC sensitizers. Thus, DSSCs were fabricated based on these dyes. The cells based on YQ4 showed the power conversion efficiency of 5.00%, which is higher than those of 4.23% and 4.38% for YQ2 and YQ3, respectively. This observation may be attributed to the suppression of the dye aggregation by the hexyl group attached to the thienyl ring of YQ4. On the other hand, YQ2–YQ4 demonstrated lower efficiencies compared with YQ1, which may be ascribed to the floppy structures of the cyanoacrylic acid-based porphyrins that provide free space for charge recombination. As a result, the DSSCs based on YQ1 exhibited the highest efficiency of 6.01%. This work demonstrates that the introduction of 2-diphenylaminothiophene into a porphyrin framework can obviously red-shift and broaden the absorption bands of the porphyrin dyes, resulting in high solar cell efficiencies. Hence, the introduction of 2-diphenylaminothiophene as the electron donor may be promising for the design of efficient porphyrin-based DSSC sensitizers.
Co-reporter:Xing Rui, Quan-Zheng Zha, Tian-Tian Wei, Yong-Shu Xie
Inorganic Chemistry Communications 2014 Volume 48() pp:111-113
Publication Date(Web):October 2014
DOI:10.1016/j.inoche.2014.08.022
•A porphyrin ligand with two carboxyl and two pyridyl moieties was synthesized.•Two interesting coordination polymers with 2D and 3D structures were obtained.•Structures of the complexes were modulated by the metal centers.In this work, we designed and synthesized a porphyrin-based ligand, 5,15-bis(4-carboxyphenyl)-10,20-dipyridyl porphyrin, DCDPP (H4L), which bears two carboxyl and two pyridyl moieties. Coordination of Mn(II) and Zn(II) acetates with DCDPP afforded two novel coordination polymers, [MnHL]n (1) and [ZnH2L]n·nCH3COOH (2), respectively. Single crystal X-ray diffraction analyses revealed that complex 1 exhibits 2D coordination networks, which are further linked through hydrogen bonds to form a 3D network structure. In complex 2, 1D zigzag coordination chains were generated and further linked through hydrogen bonds to form a 2D structure. Interestingly, the carboxyl moieties in these complexes are noncoordinated, and the pyridyl moieties are either coordinated or noncoordinated, and the noncoordinated carboxyl and pyridyl moieties are involved in intermolecular hydrogen bonds, which are favorable for forming the hydrogen-bonded networks.Two novel coordination polymers [MnHL]n (1) and [ZnH2L]n·nCH3COOH (2) have been synthesized from a porphyrin-based ligand (DCPDPP, H4L) containing two pyridyl and two carboxyl moieties. By linkage of coordination bonds and hydrogen bonds, 3D and 2D networks were observed for 1 and 2, respectively.
Co-reporter:Bin Chen, Xi Sun, Xin Li, Hans Ågren, Yongshu Xie
Sensors and Actuators B: Chemical 2014 199() pp: 93-100
Publication Date(Web):
DOI:10.1016/j.snb.2014.03.087
Co-reporter:Dr. Yubin Ding;Dr. Xin Li;Dr. Jonathan P. Hill;Dr. Katsuhiko Ariga;Dr. Hans Ågren;Dr. Joakim Andréasson;Dr. Weihong Zhu;Dr. He Tian;Dr. Yongshu Xie
Chemistry - A European Journal 2014 Volume 20( Issue 40) pp:12910-12916
Publication Date(Web):
DOI:10.1002/chem.201403830
Abstract
Compared with most of the reported logic devices based on the supramolecular approach, systems based on individual molecules can avoid challenging construction requirements. Herein, a novel dioxoporphyrin DPH22 was synthesized and two of its tautomers were characterized by single-crystal X-ray diffraction studies. Compound DPH22 exhibits multichannel controllable stepwise tautomerization, protonation, and deprotonation processes through interactions with H+ and F− ions. By using the addition of H+ and F− ions as inputs and UV/Vis absorption values at λ=412, 510, 562, and 603 nm as outputs, the controlled tautomerism of DPH22 has been successfully used for the construction of an integrated molecular level half-subtractor and comparator. In addition, this acid/base-switched tautomerism is reversible, thus endowing the system with ease of reset and recycling; consequently, there is no need to modulate complicated intermolecular interactions and electron-/charge-transfer processes.
Co-reporter:Yueqiang Wang;Bin Chen;Dr. Wenjun Wu;Dr. Xin Li;Dr. Weihong Zhu;Dr. He Tian ;Dr. Yongshu Xie
Angewandte Chemie International Edition 2014 Volume 53( Issue 40) pp:10779-10783
Publication Date(Web):
DOI:10.1002/anie.201406190
Abstract
Porphyrin dyes containing the carbazole electron donor have been designed and optimized by wrapping the porphyrin framework, introducing an additional ethynylene bridge to extend the wavelength range of light absorption, and further suppression of the dye aggregation by introducing additional alkoxy chains. Application of a cosensitization approach results in improved current density (Jsc) and open-circuit voltage (Voc) values, thus achieving the highest cell efficiency of 10.45 %. This work provides an effective combined strategy of molecular design and cosensitization for developing efficient dye-sensitized solar cells (DSSCs). In addition, carbazole has been demonstrated to be a promising donor for porphyrin sensitizers.
Co-reporter:Pingchun Wei;Kai Zhang;Dr. Xin Li;Deying Meng;Dr. Hans Ågren;Dr. Zhongping Ou;Dr. Seikweng Ng;Dr. Hiroyuki Furuta;Dr. Yongshu Xie
Angewandte Chemie International Edition 2014 Volume 53( Issue 51) pp:14069-14073
Publication Date(Web):
DOI:10.1002/anie.201408307
Abstract
The first neo-confused hexaphyrin(1.1.1.1.1.0) was synthesized by oxidative ring closure of a hexapyrrane bearing two terminal “confused” pyrroles. The new compound displays a folded conformation with a short interpyrrolic C⋅⋅⋅N distance of 3.102 Å, and thus it readily underwent ring fusion to afford a neo-fused hexaphyrin with an unprecedented 5,5,5,7-tetracyclic ring structure. Furthermore, coordination of CuII triggered a ring opening/contracting reaction to afford a CuII complex of an N-linked pentaphyrin derivative. The roles of reactive NC bonds in the porphyrinoid macrocycles were demonstrated.
Co-reporter:Cong-Wu Ge;Chong-Yu Mei;Jun Ling;Jin-Tu Wang;Fu-Gang Zhao;Long Liang;Hong-Jiao Li;Yong-Shu Xie;Wei-Shi Li
Journal of Polymer Science Part A: Polymer Chemistry 2014 Volume 52( Issue 8) pp:1200-1215
Publication Date(Web):
DOI:10.1002/pola.27108
ABSTRACT
Donor–acceptor (D–A) conjugated copolymers are one of known classes of organic optoelectronic materials and have been well developed. However, less attention has been paid on acceptor–acceptor (A–A) conjugated analogs. In this work, two types of A–A conjugated copolymers, namely P1-Cn and P2-Cn (n is the carbon number of their alkyl side chains), were designed and synthesized based on perylenediimide (PDI) and 2,1,3-benzothiadiazole (BT). Different from P1-Cn, P2-Cn polymers have additional acetylene π-spacers between PDI and BT and thus hold a more planar backbone configuration. Property studies revealed that P2-Cn polymers possess a much red-extended UV–vis absorption spectrum, stronger π–π interchain interactions, and one-order larger electron mobility in their neat film state than P1-Cn. However, all-polymer solar cells using P1-Cn as acceptor component and poly(3-hexyl thiophene) or poly(2,7-(9,9-didodecyl-fluoene)-alt−5,5′-(4,7-dithienyl-2-yl-2,1,3-benzothiadiazole) as donor component exhibited much better performance than those based on P2-Cn. Apart from their backbone chemical structure, the side chains were found to have little influence on the photophysical, electrochemical, and photovoltaic properties for both P1-Cn and P2-Cn polymers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1200–1215
Co-reporter:Yueqiang Wang;Bin Chen;Dr. Wenjun Wu;Dr. Xin Li;Dr. Weihong Zhu;Dr. He Tian ;Dr. Yongshu Xie
Angewandte Chemie 2014 Volume 126( Issue 40) pp:10955-10959
Publication Date(Web):
DOI:10.1002/ange.201406190
Abstract
Porphyrin dyes containing the carbazole electron donor have been designed and optimized by wrapping the porphyrin framework, introducing an additional ethynylene bridge to extend the wavelength range of light absorption, and further suppression of the dye aggregation by introducing additional alkoxy chains. Application of a cosensitization approach results in improved current density (Jsc) and open-circuit voltage (Voc) values, thus achieving the highest cell efficiency of 10.45 %. This work provides an effective combined strategy of molecular design and cosensitization for developing efficient dye-sensitized solar cells (DSSCs). In addition, carbazole has been demonstrated to be a promising donor for porphyrin sensitizers.
Co-reporter:Cong-Wu Ge;Chong-Yu Mei;Jun Ling;Fu-Gang Zhao;Hong-Jiao Li;Long Liang;Jin-Tu Wang;Jin-Cheng Yu;Wei Shao;Yong-Shu Xie;Wei-Shi Li
Journal of Polymer Science Part A: Polymer Chemistry 2014 Volume 52( Issue 16) pp:2356-2366
Publication Date(Web):
DOI:10.1002/pola.27248
ABSTRACT
Besides the donor–acceptor (D–A) type, acceptor–acceptor (A–A) polymers are another class of important alternative conjugated copolymers, but have been less studied in the past. In this study, two kinds of A–A polymers, P1 and P2, have been designed and synthesized based on diketopyrrolopyrrole in combination with the second electron-deficient unit, perylenediimide or thieno[3,4-c]pyrrole-4,6-dione. UV–vis absorption spectroscopy revealed that these two kinds of polymers have a band gap of 1.28–1.33 eV. Their highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels are around −5.6 and −4.0 eV for P1 polymers, whereas −5.4 and −3.7 eV for P2 polymers, respectively. Density functional theory study disclosed that P1 backbone is in a vastly twisting state, whereas that of P2 is completely planar. Furthermore, organic field-effect transistor devices were fabricated using these two kinds of polymers as the active material. Of interest, the devices based on P1 polymers displayed n-channel behaviors with an electron mobility in the order of 10−4 cm2 V−1 s−1. In contrast, the P2-based devices exhibited only p-channel charge transportation characteristics with a hole mobility in the order of 10−3 cm2 V−1 s−1. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2356–2366
Co-reporter:Yongshu Xie ; Pingchun Wei ; Xin Li ; Tao Hong ; Kai Zhang ;Hiroyuki Furuta
Journal of the American Chemical Society 2013 Volume 135(Issue 51) pp:19119-19122
Publication Date(Web):December 9, 2013
DOI:10.1021/ja4112644
Cyclization of a pentapyrrane with two terminal β-linked pyrroles afforded a dihydrosapphyrin isomer (1) with the pyrroles linked in a unique β,α–α,β mode, which was rather reactive, and thus it readily underwent a ring-contracted rearrangement to a pyrrolyl norrole (2), and succeeding ring expansion to a terpyrrole-containing isosmaragdyrin analogue (4). 1, 2, and 4 contain the internal ring pathways with a minimum of 17, 15, and 16 atoms, respectively. 1, 2, and 4 are almost nonfluorescent, whereas the complex of 2 with Zn2+ shows a distinct NIR emission peak at 741 nm. The unprecedented pyrrole transformation chemistry by confusion approach is illustrated.
Co-reporter:Bin Chen, Gang Yu, Xin Li, Yubin Ding, Cheng Wang, Zhiwei Liu and Yongshu Xie
Journal of Materials Chemistry A 2013 vol. 1(Issue 44) pp:7409-7417
Publication Date(Web):20 Sep 2013
DOI:10.1039/C3TC31751J
Starting from two simple units of anthracene and 2,2′-dipyridylamine, a series of new luminescent compounds 1–8 were designed and synthesized by a combined strategy of changing the connection mode between the two units, extending the conjugation size, and introducing an additional electron donor. Photophysical properties of 1–8 were investigated and discussed on the basis of solvatochromic behaviour, theoretical calculations, crystal structure, and optimized structures. Interestingly, the emission wavelengths of these compounds could be successfully tuned from violet to red both in solutions and the solid-state, and prominent positive solvatochromism was observed for the compounds with a D–π–A framework. Consider compound 7 as an example, it shows peaks at 526 nm and 627 nm in cyclohexane and DMSO, respectively. Meanwhile, the quantum yield was decreased from 0.80 in cyclohexane to 0.12 in DMSO. The introduction of bulky groups was demonstrated to be effective for suppressing the aggregation effect and thus improving the solid state emission quantum yield. These results indicate that the combined structure modulation strategy offers a powerful tool for tuning the emission behaviour. To demonstrate the possibility of practical applications, 2 was employed as the emitting material for the fabrication of deep-blue organic light-emitting diodes (OLEDs), which showed a maximum external quantum efficiency of 2.2%. The CIE coordinates of (0.15, 0.08) are indicative of excellent blue color purity.
Co-reporter:Bin Chen, Yubin Ding, Xin Li, Weihong Zhu, Jonathan P. Hill, Katsuhiko Ariga and Yongshu Xie
Chemical Communications 2013 vol. 49(Issue 86) pp:10136-10138
Publication Date(Web):05 Sep 2013
DOI:10.1039/C3CC46008H
For the rational design of fluorescence “turn-on” cyanide probes, a general strategy is developed by introducing a dicyanovinyl group at the sterically demanding position of a large π framework.
Co-reporter:Quanzheng Zha, Caixia Ding, Xing Rui, and Yongshu Xie
Crystal Growth & Design 2013 Volume 13(Issue 10) pp:4583-4590
Publication Date(Web):September 5, 2013
DOI:10.1021/cg4011289
The design and syntheses of porphyrin-based ligands are attractive for creating coordination assemblies with novel structures and intriguing properties. In this work, we designed and synthesized a novel porphyrin-based ligand 5,10,15,20-tetrakis(4,4′-dipyridylaminophenylene)porphyrin (TDPAP, H2L) by the introduction of four peripheral 4,4′-dipyridylamine moieties to a porphyrin platform. Starting from this novel ligand, the protonated form of the ligand H4LCl2·2CH3OH·2H2O (1) and four coordination polymers [Mn(III)Mn(II)LCl3(DMF)]n (2), [Cu4L(CH3COO)5(HCOO)(CH3COOH)(H2O)3]n·nCH3COOH·nH2O (3), [Zn3L(CH3COO)4]n (4), and [Cd2H2L(CH3COO)4]n·nDMF·nCH3COOH·2nH2O (5) were synthesized. Single crystal X-ray diffraction analyses revealed that a rich structural diversity was observed for these compounds due to the coordination of the multiple peripheral pyridines as well as the porphyrin core. 1 displays a hydrogen bonded one-dimensional (1D) structure composed of [(H2O)2Cl2]2– moieties. Complex 2 shows interpenetrated two-dimensional (2D) coordination networks, which are further linked by π···π stacking interactions to afford a three-dimensional (3D) structure. 3 shows a 2D sheet composed of 50- and 70-membered metallomacrocycles. In complex 4, 1D zigzag coordination chains were generated and further linked to form a 2D structure. Complex 5 has a stairlike 2D structure formed by the linkage of 1D coordination chains through the bridging of binuclear [Cd2(CO2)4] subunits. In these compounds, TDPAP shows a unique coordination behavior. It may bind 4–7 metal centers, and it demonstrates conformational flexibility and the ability to form intermolecular hydrogen bonds and π···π interactions, which contribute to the formation of novel supramolecular structures. On the basis of the novel structures, the solid state emissions of the compounds were also investigated.
Co-reporter:Yubin Ding, Tong Li, Xin Li, Weihong Zhu and Yongshu Xie
Organic & Biomolecular Chemistry 2013 vol. 11(Issue 16) pp:2685-2692
Publication Date(Web):25 Feb 2013
DOI:10.1039/C3OB40121A
Most reported Zn2+ probes suffer from the interference of background fluorescence originated from the conjugated structures of commonly utilized fluorophores. In this work, three novel meso-hydroxyl group substituted dipyrromethanes DPMOH1–DPMOH3 were synthesized and found to be colourless and nonfluorescent due to the interruption of the conjugated π system by an sp3 carbon between the two pyrrolic units. Interestingly, only the addition of Zn2+ to the solutions of DPMOH1–DPMOH3 promoted their oxidation to dipyrrin forms, and bright fluorescence “turn on” was observed due to the formation of corresponding dipyrrin complexes with the dipyrrin:zinc stoichiometry of 2:1. Zn2+ detection mechanism was investigated by UV-Vis, fluorescence, 1H NMR and HRMS analyses, which can be ascribed to the CHEF type fluorescence enhancement, resulting from good rigidity of the dipyrrin complexes. Hence, DPMOH1–DPMOH3 can be used as fluorescence turn-on Zn2+ probes with the advantage of no background fluorescence.
Co-reporter:Yueqiang Wang, Xin Li, Bo Liu, Wenjun Wu, Weihong Zhu and Yongshu Xie
RSC Advances 2013 vol. 3(Issue 34) pp:14780-14790
Publication Date(Web):11 Jun 2013
DOI:10.1039/C3RA40788H
Two novel porphyrin dyes (Q1 and Q2) bearing alkoxyl chains with a carbazole moiety as the electron donor have been synthesized and utilized as sensitizers for dye-sensitized solar cells (DSSCs). Compared with Q2, the molecule of Q1 has an additional ethynylene bridge between the carbazole moiety and the porphyrin framework. Photophysical and electrochemical properties of the two dyes were investigated by UV-vis, fluorescence spectroscopy and cyclic voltammetry. DFT calculations indicated that Q2 has a more twisted non-planar conformation associated with a smaller π conjugation size because of the absence of ethynylene bridge, which resulted in its better solubility and larger amount of adsorption on TiO2. Compared with Q1, Q2 showed better photovoltaic performance, with a short-circuit photocurrent density (Jsc) of 11.3 mA cm−2, an open-circuit photovoltage (Voc) of 0.68 V, and a fill factor (ff) of 0.71, corresponding to an overall conversion efficiency of 5.51% under standard global AM 1.5 solar light conditions. The additional ethynylene bridge in Q1 extends the absorption bands to a longer wavelength region with the absorption threshold of 743 nm on the TiO2 film compared with that of 681 nm for Q2, but the cell efficiency is decreased to 2.22%, which may be ascribed to the worse solubility and stronger aggregation tendency resulting from the better molecule planarity. These results indicate that the extension of the absorption bands to a longer wavelength region by the introduction of an additional ethynylene bridge may result in worse solubility and more severe aggregation, and thus decrease the cell efficiency. For the design of efficient DSSC sensitizers, these contradictory effects must be fully considered and well balanced.
Co-reporter:Yun-Yu Tang, Cai-Xia Ding, Seik-Weng Ng and Yong-Shu Xie
RSC Advances 2013 vol. 3(Issue 39) pp:18134-18141
Publication Date(Web):31 Jul 2013
DOI:10.1039/C3RA43405B
The coordination of Zn(II), Ag(I), Cu(II), Cu(I) and Co(II) salts with N,N,N′,N′-tetrakis(4-pyridyl)-1,4-phenylenediamine (L) generated seven novel supramolecular coordination assemblies, {[CuI6L3Cl6]·3MeCN}n (1), {[CuI2LCl2]·2DMSO}n (2), {[CuILI]}n (3), {[Zn2L(HCOO)4]}n (4), {[Ag4L2(N3)4]·2H2O}n (5), {[Co4L2(SO4)4(H2O)12]·2CH3CN}n (6) and {[CuL(CH3COO)2(H2O)2]·2MeOH}n (7). In complexes 1 and 2, the Cu(II) atoms have been converted to Cu(I). Complexes 1, 4 and 5 show 1D or 2D coordination structures, and all of them are further linked by π⋯π stacking interactions to afford 3D structures. Complex 2 has a 2D structure composed of Cu2Cl2 units and L ligands. Complex 3 exhibits a doubly interpenetrated 3D structure. In complex 6, the 2D coordination networks are further linked by hydrogen bonds to afford a 3D supramolecular structure. Similar to complex 6, the 1D chains in complex 7 are assembled into a 2D network through hydrogen bonds. Based on the novel structures, the solid state luminescent properties of the complexes were investigated and discussed.
Co-reporter:Cai-Xia Ding, Chang-Hua He, Yong-Shu Xie
Chinese Chemical Letters 2013 Volume 24(Issue 6) pp:463-466
Publication Date(Web):June 2013
DOI:10.1016/j.cclet.2013.03.030
Three novel Zn(II) complexes, [Zn4L1Cl4]·3H2O (1), [Zn4L2Cl4]·2DMF (2) and [Zn4L3Cl4]·H2O (3), have been synthesized and structurally characterized. In these complexes, interesting 32-membered dodecadentate macrocyclic ligands were generated in situ by ‘2 + 2’ type condensation reactions between a tetraamine and various dialdehydes. All the complexes are isostructurally tetranuclear Zn(II) complexes, containing endogenous alkoxo and phenoxo bridges. Applications of the macrocyclic ligands as Zn2+ sensors have been investigated. Take H4L1 for example, it exhibits a 4-fold fluorescence enhancement upon the addition of 2 equiv. of Zn2+ in MeOH.Three tetranuclear Zn(II) complexes with in situ generated macrocyclic Schiff base ligands have been synthesized and structurally characterized, and the macrocyclic ligands have been used in fluorescent Zn2+ sensing.
Co-reporter:Caixia Ding;Chen Gao;Dr. Seikweng Ng;Dr. Bingwu Wang;Dr. Yongshu Xie
Chemistry - A European Journal 2013 Volume 19( Issue 30) pp:9961-9972
Publication Date(Web):
DOI:10.1002/chem.201301041
Abstract
Complexes of new Schiff base ligands generated in situ from the reaction of 1-aminoglycerol, aldehydes, and metal ions are reported. [Cu4(HL1)4] (1) and [Ni4O(HL1)3(H2O)3)]⋅6 H2O⋅DMF⋅DMSO (2) have M4O4 cubane cores, with the L/M molar ratios of 4:4 and 3:4, respectively. [MnIII3MnIINaOCl4(HL1)3]⋅3 MeCN (3) has a unique pentanuclear trigonal propeller-shaped MnIII3MnIINa core structure, and the coordination assemblies are linked by hydrogen bonds to afford a 3D channel structure. [Cu2(HL2)2] (4) has a bis(μ2-alkoxo)-bridged Cu2O2 core, with the binuclear species linked by hydrogen bonds to afford a 1D double-chain. [Ni7(OH)2(OCH3)4(H2L3)2(MeOH)2(H2O)2]- (ClO4)2⋅10 H2O (5) has a heptanuclear structure containing heptadentate di-Schiff base ligands, with the nickel(II) ions bridged by phenoxo, alkoxo, hydroxo, and methoxo groups to afford a very rare face-sharing hexadruple defective cubane core with a Ni@Ni6 arrangement. The lattice water molecules are linked by hydrogen bonds to form helical chains, which are further hydrogen-bonded to the coordination moieties to afford a 2D network. Variable temperature magnetic susceptibility measurements and nonlinear data-fitting revealed that the “2+4” type of cubane complex 1 shows medium intradimeric ferromagnetic interactions and weak interdimeric ferromagnetic interactions. For complexes 2 and 5, coexistent ferro- and antiferromagnetic couplings afford a non-zero spin ground state. However, compound 3 shows antiferromagnetic interactions between MnIII and MnII, and ferromagnetic interactions between the MnIII centers, resulting in a global antiferromagnetic behavior. In conclusion, the reaction of 1-aminoglycerol with aldehydes and metal salts afforded polynuclear complexes with a rich structural diversity and remarkable magnetic behavior.
Co-reporter:Yubin Ding, Xin Li, Tong Li, Weihong Zhu, and Yongshu Xie
The Journal of Organic Chemistry 2013 Volume 78(Issue 11) pp:5328-5338
Publication Date(Web):May 13, 2013
DOI:10.1021/jo400454e
With the purpose of developing readily synthesized CHEF (chelation-enhanced fluorescence) type Zn2+ probes with relatively simple molecular structures and excellent sensing behavior, p-anisoyl chloride was used for the acylation of 5-(pentafluorophenyl)dipyrromethane. Interestingly, the α,β′-diacylated product PS2 with a unique substitution mode was obtained in high yield in addition to the normal α-substituted mono- and diacylated products PS1 and PS3. Further oxidation of PS1–PS3 afforded dipyrrins S1–S3. Crystal structure and 1H NMR measurements of S2 demonstrate the existence of a pure tautomer, which is consistent with DFT calculations. S1–S3 show highly Zn2+ selective “turn-on” fluorescence based on a CHEF mechanism by the formation of 2:1 (probe:metal) Zn2+ complexes. The emission colors can be easily tuned from green to red by changing the dipyrrin substitution modes. Furthermore, these probes demonstrate fast responses and wide applicable pH ranges. Among them, S2 shows the highest Zn2+ sensitivity, with a detection limit of 4.4 × 10–8 M.
Co-reporter:Bo Liu, Weihong Zhu, Yueqiang Wang, Wenjun Wu, Xin Li, Baoqin Chen, Yi-Tao Long and Yongshu Xie
Journal of Materials Chemistry A 2012 vol. 22(Issue 15) pp:7434-7444
Publication Date(Web):08 Mar 2012
DOI:10.1039/C2JM16804A
In the design of efficient sensitizers for dye-sensitized solar cells (DSSCs), it is vital to modulate the HOMO and LUMO orbitals by introducing suitable donor and acceptor groups. In this respect, triphenylamine has been extensively used as the donor group. Porphyrin has strong absorption in the UV-Vis range, which makes it a promising dye candidate. In addition, a porphyrin molecule contains eight β positions and four meso-positions, which may be conveniently utilized for introducing multiple donor and acceptor moieties. In this work, various numbers of triphenylamine and trimethoxyphenyl groups are introduced to the porphyrin meso-positions as electron donors, with the aim to systematically modulate the energy levels and investigate the effect on the efficiency of the DSSCs. The HOMO–LUMO energy gaps remain almost constant irrespective of the donor groups, thus, the variation of the donors leads to a contradictory effect on the processes of electron injection and dye regeneration. In the case of the zinc porphyrin with two triphenylamine units and one trimethoxyphenyl group as the electron donors (M3T2P), moderate and well-matched HOMO and LUMO energy levels are observed, thus affording high efficiencies for both the electron injection and the dye regeneration processes. The overall conversion efficiencies (η) of the DSSCs based on these dyes lie in the range of 2.70–5.45%, with the optimized performance achieved by M3T2P, which can be rationalized by the efficient electron injection and dye regeneration processes, and the long electron lifetime, as demonstrated by the electrochemical impedance spectroscopy measurements. These results provide further insights into the strategy for elevating the efficiencies of DSSCs, especially those based on porphyrins, simply by modulating the electron donor groups.
Co-reporter:Jonathan P. Hill, Navaneetha K. Subbaiyan, Francis D’Souza, Yongshu Xie, Satyajit Sahu, Noelia M. Sanchez-Ballester, Gary J. Richards, Toshiyuki Mori and Katsuhiko Ariga
Chemical Communications 2012 vol. 48(Issue 33) pp:3951-3953
Publication Date(Web):27 Feb 2012
DOI:10.1039/C2CC30712J
Tetrapyrazinoporphyrazine substituted at its periphery with eight antioxidant 3,5-di-t-butyl-4-hydroxyphenyl groups behaves as a turn-on fluorescent sensor for fluoride anions. Conversely, the precursor antioxidant-substituted 1,2-phthalonitrile was found to act in turn-off mode suggesting that the origin of the phenomenon lies at the phenolate-substituted 1,4-pyrazinyl moiety.
Co-reporter:Yongshu Xie, Yubin Ding, Xin Li, Cheng Wang, Jonathan P. Hill, Katsuhiko Ariga, Weibing Zhang and Weihong Zhu
Chemical Communications 2012 vol. 48(Issue 94) pp:11513-11515
Publication Date(Web):23 Oct 2012
DOI:10.1039/C2CC36140J
2,2′-Dipyridylamine and anthracene units were linked to afford highly emissive compounds whose Cu2+ ensembles were developed as effective fluorescence turn-on CN− probes.
Co-reporter:Yubin Ding, Tong Li, Weihong Zhu and Yongshu Xie
Organic & Biomolecular Chemistry 2012 vol. 10(Issue 21) pp:4201-4207
Publication Date(Web):27 Mar 2012
DOI:10.1039/C2OB25297J
Cyanide sensing has attracted increasing interest due to its toxicity and wide use in industrial activities. Herein, we developed three colorimetric cyanide sensors by the modification of the α-position of a dipyrrin chromophore with various carbonyl groups, namely, C6F5CO, C6H5CO and CHO for 1, 2 and 3, respectively. In dichloromethane, these sensors respond to both CN− and F− with distinct colour changes. UV-Vis, 1H NMR and HRMS measurements imply a two-process interaction between the sensors and CN−. Initially, CN− forms a hydrogen bond with the NH moiety, and then it attacks the carbonyl group of the sensors via a nucleophilic addition reaction. In contrast, in aqueous systems, only cyanide induced vivid solution colour changes from light yellow to pink via nucleophilic addition reactions. The CN− detection limits reach a micromolar level of 3.6 × 10−6 M, 4.2 × 10−6 M and 7.1 × 10−6 M for 1, 2 and 3, respectively. In view of the easy synthesis and the highly selective recognition of CN− with vivid colour changes, 1–3 may be developed as a novel and promising prototype of selective and sensitive colorimetric cyanide sensors.
Co-reporter:Cai-Xia Ding, Jia Ni, Yu-Hua Yang, Seik-Weng Ng, Bing-Wu Wang and Yong-Shu Xie
CrystEngComm 2012 vol. 14(Issue 21) pp:7312-7319
Publication Date(Web):07 Aug 2012
DOI:10.1039/C2CE25966D
By the reaction of an alkoxyl containing tetraamine, 1,3-bis[(2-aminoethyl)amino]-2-propanol, with various aldehydes, O-vanillin and 2,6-diformyl-4-cresol, in the presence of various metal cations, four novel complexes were synthesized and structurally characterized. Complexes [CoHL1](ClO4)·2MeOH (1) and [NiH2L2](ClO4)2·0.5MeOH (2) have mononuclear structures, with the linear di-Schiff base ligand (HL1)2− and mono-Schiff base ligand H2L2 generated from in situ reactions under various pH conditions. In complexes [Ni4L3(SCN)3(MeOH)]Cl·2.5MeOH (3), and [Cu8(H2L3)2(OH)4(ClO4)](SCN)6(ClO4)·8H2O (4), an interesting 32-membered dodecadentate macrocyclic ligand H4L3 comprising four Schiff base CN double bonds was generated by a “2+2” type condensation reaction between the tetraamine and the dialdehyde. Complex 3 has a tetranuclear Ni4 coordination structure with all 12 coordinating atoms of (L3)4− utilized for coordination, and the alkoxyl groups are deprotonated and coordinated in a bridging mode. Complex 4 exhibits an octanuclear Cu8 coordination structure, with a ClO4− bridging two tetranuclear [Cu4H2L3(OH)2]4+ moieties through four weak axial Cu–O coordination bonds. In complex 4, only 10 coordinating atoms of (L3)4− are utilized for coordination, with the two alkoxyl groups left neutral and noncoordinated. It is noteworthy that H4L3 has two long saturated chains in the molecule. Therefore, it has good flexibility and tends to have a nonplanar structure. Variable temperature magnetic data for 3 and 4 indicated the existence of antiferromagnetic interactions, which were discussed based on the structural results.
Co-reporter:Caixia Ding, Fanhua Zeng, Jia Ni, Bingwu Wang, and Yongshu Xie
Crystal Growth & Design 2012 Volume 12(Issue 4) pp:2089-2096
Publication Date(Web):March 10, 2012
DOI:10.1021/cg300096n
In situ formation of ligands is an efficient approach to synthesizing novel complexes with unique coordinating moieties. Oxazolidines and oxazinanes are 1,3-N,O-containing five-membered and six-membered heterocycles, respectively. Metal complexes of ligands derived from these two heterocycles are rather rare. In this work, we designed and synthesized a novel multihydoxy ligand, 2-((2,3-dihydroxypropylamino)methyl)phenol (H3L1). It contains both aminoethanol and aminopropanol units, which may be employed to react with aldehydes to afford oxazolidines and oxazinanes, respectively. Thus, H3L1 was reacted with metal salts in the absence or presence of aldehydes to afford complexes [Cu(HL1)]2 (1), [CuL2]4·4CH3OH (2) [Zn5Na2(L3)4(DMSO)2.65(DMF)1.35]·DMF (3), and [Ni(HL4)]2 (4). Complex 1 is a dialkoxo-bridged binuclear Cu(II) complex. The coordination moieties are linked by intermolecular C–H···O hydrogen bonds to afford a 1D double-chain supramolecular structure. Interestingly, in complexes 2–4, H3L1 has been reacted with formaldehyde, salicylaldehyde, and 2,6-diformyl-4-cresol to afford novel ligands H2L2, H3L3, and H3L4, respectively. The combination of in situ formed oxazinane or oxazolidine rings with appended alkoxyl and phenol functionalities in these ligands has been demonstrated to form a rich diversity of coordination structures. Thus, 2 is a tetranuclear Cu(II) complex with a face-sharing double defective cubane core structure. In this complex, (L2)2– ligands coordinate in two different bridging modes with the Harris notations of 3.1121221311 and 3.1131231111, respectively. Complex 3 has an interesting heptanuclear Zn5Na2 core structure. A central Zn(II) is coordinated with four alkoxo O atoms from four (L3)3– ligands. Each of the O atom further bridges another Zn(II) atom, resulting in a Zn5 moiety, which is then connected to two Na+ by phenoxo O bridges, finally affording the Zn5Na2 core. The bridging mode of (L3)3– can be designated as 4.21221311312411. And Complex 4 is a binuclear Ni(II) complex containing di-μ2-phenoxo bridges. The coordination moieties are linked by intermolecular C–H···π, C–H···O, and π···π interactions to afford a two-dimensional supramolecular network. These results indicate that the combination of in situ formed oxazinane and oxazolidine rings with appended phenol and alkoxyl functionalities is an efficient approach to developing novel ligands and complexes with a rich structural diversity. Variable temperature magnetic data measurements revealed that medium antiferromagnetic interaction exists between the Cu(II) centers in complex 1 with a −2J value of 278 cm–1. And in complex 4, weak antiferromagnetic coupling occurs between the Ni(II) centers, with a −2J value of 9.36 cm–1.
Co-reporter:Caixia Ding, Xing Li, Yubin Ding, Xin Li, Seik Weng Ng, and Yongshu Xie
Crystal Growth & Design 2012 Volume 12(Issue 7) pp:3465-3473
Publication Date(Web):May 23, 2012
DOI:10.1021/cg201655n
The design and syntheses of novel ligands are essential for developing coordination compounds with novel structures and interesting properties. In this work, we designed and synthesized a novel ligand bis(4,4′-dipyridylaminophenylene)butadiyne (L) by attaching two 4,4′-dipyridylamine moieties to a flexible butadiyne linker. Starting from this novel ligand, seven coordination polymers [Zn2L(HCOO)3(OH)]n (1), [Cd2L2Cl4]n·3nDMF·3nH2O (2), [CdLBr2]n (3), [Cd6L3(SO4)6]n·4nMeCN (4), [Hg2LBr4]n·3nCH2Cl2·nH2O (5), [Cu2LI2]n·0.5nCH2Cl2 (6), and [Ag2L(H2O)2]n(NO3)2n·2nH2O (7) were synthesized. Single-crystal X-ray diffraction analyses revealed that two forms of the ligand crystals, L and L·0.5DMF present straight and bent conformations, respectively, because of the flexibility of the butadiyne unit. A rich structural diversity was observed for its d10 metal complexes. Complexes 1 and 5 present ladder-like structures. In complexes 2 and 4, the ligand molecules are linked by metal atoms to afford 3D supramolecular structures. It is noteworthy that the 3D structure of complex 4 consists of interesting infinite {Cd6(SO4)6}∞ chains, whereas complexes 3, 6, and 7 exhibit 2D network structures. Interestingly, in the crystal of complex 7, each ligand links four metal ions and each Ag ion bridges two ligands, leading to the formation of undulated 2D sheets with large cavities composed of 66-membered metallomacrocycles, which are interpenetrated by three other such 2D sheets, affording a 4-fold interpenetrated structure. In summary, the complex structures are dependent on the metal ions and the anions. In addition, the flexibility of the butadiyne moiety provides additional means for modulating the structures. Solid state photoluminescence of the free ligand and the complexes shows emission maxima within the range of 420–515 nm, which can be modulated by the conformations of the ligand in addition to the variation of the metal ions and anions, and the introduction of the butadiyne unit has a bathochromic effect.
Co-reporter:Yubin Ding, Yongshu Xie, Xin Li, Jonathan P. Hill, Weibing Zhang and Weihong Zhu
Chemical Communications 2011 vol. 47(Issue 19) pp:5431-5433
Publication Date(Web):11 Apr 2011
DOI:10.1039/C1CC11493J
Di- and tripyrrin sensors D1–D4 exhibit CHEF-type fluorescence enhancement by factors up to 72 upon addition of 1 equiv. Zn2+, with tunable emission colours between green (D1) and red (D4).
Co-reporter:Cai-Xia Ding, Jia Ni, Chang-Hua He, Fan-Hua Zeng, Wei-Hong Zhu, Yong-Shu Xie
Inorganic Chemistry Communications 2011 Volume 14(Issue 2) pp:370-373
Publication Date(Web):February 2011
DOI:10.1016/j.inoche.2010.12.002
A novel coordination polymer [Cu2(HL)(CH3OH)(ClO4)]n(ClO4)n (1) has been synthesized from a multihydoxy Schiff base ligand, 1,3-bis(salicylidene iminoethylamino)-2-propanol (H3L). Single crystal X-ray diffraction analyses reveal that the coordination polymer is comprised of binuclear units, wherein the copper centers are bridged by a single alkoxo group, with a large bridging angle of 135.06°. By the linkage of an intramolecular hydrogen bond, an interesting pseudo-macrocyclic structure is formed. The binuclear moieties are assembled into a 1-D chain by the linkage of axially coordinated ClO4− anions, and the 1-D chains are further connected via intermolecular C-H⋅⋅⋅π stacking interactions, affording a zipper-like double chain supramolecular structure. Variable-temperature magnetic data measurements and analyses show the existence of strong antiferromagnetic interaction between the copper centers within the binuclear unit, mediated by the single alkoxo bridge with a − 2J value of 545 cm− 1.A novel coordination polymer [Cu2(HL)(CH3OH)(ClO4)]n(ClO4)n (1) has been synthesized from a multihydoxy Schiff base ligand, 1,3-bis(salicylidene iminoethylamino)-2-propanol (H3L). 1 has a zipper-like double chain supramolecular structure formed by weak axial coordination and intermolecular C-H⋅⋅⋅π stacking interactions.Research Highlights► Pseudo-macrocyclic structure is formed by the linkage of an intramolecular H-bond. ► Complex structure is modulated by the ligand rigidity. ► An interesting supramolecular zipper-like double chain structure is formed. ► Strong antiferromagnetic coupling is mediated by a single alkoxo-bridge.
Co-reporter:Quanguo Wang, Yongshu Xie, Yubin Ding, Xin Li and Weihong Zhu
Chemical Communications 2010 vol. 46(Issue 21) pp:3669-3671
Publication Date(Web):16 Apr 2010
DOI:10.1039/C001509A
The combination of pyrrole and hemiquinone units produced a novel prototype of efficient colorimetric fluoride sensors, and the presence of the tautomerism effect provides additional means of modulating the sensing behavior.
Co-reporter:Fanhua Zeng, Jia Ni, Quanguo Wang, Yubin Ding, Seik Weng Ng, Weihong Zhu and Yongshu Xie
Crystal Growth & Design 2010 Volume 10(Issue 4) pp:1611-1622
Publication Date(Web):February 19, 2010
DOI:10.1021/cg901182c
Self-assembly of N,N,N′,N′-tetra(4-pyridyl)-1,4-phenylenediamine (L1) and N,N-di(2-pyridyl)-N′,N′-di(4-pyridyl)-1,4-phenylenediamine (L2) with MX2 (M = Zn, Cd, and Hg; X = Cl, Br, and I) generated novel supramolecular structures with a rich structural diversity. In the crystal of L1, all pyridyl rings are involved in intermolecular π···π stacking and T-shaped C−H···π interactions to form a two-dimensional (2D) network. [CdL1Cl2]n·nH2O (4), [CdL1I2]n (6), [HgL1Cl2]n (7), [HgL1Br2]n (8), [Cd4(L2)4Cl8]n·2nDMF (13), [CdL2Br2]n (14), [CdL2I2]n (15), and [HgL2Cl2]n·0.5nDMF (16) are coordination polymers. In complex 4, L1 utilizes all its pyridyl nitrogens to coordinate with Cd(II) centers to afford an unprecedented three-dimensional (3D) binodal (3,4)-connected network with the Schläfli symbol of (8.102)2(84.102). Complexes 6, 7, 8, 14, and 15 have zigzag or centipede-like 1D coordination structures. For complex 13, each Cd has an octahedral coordination environment, and the Cd centers are linked by dichloro-bridges to form interesting infinite (CdCl2)∞ chains, which are further bridged by L2 ligands to form a 2D coordination network. Crystal of 16 has a one-dimensional (1D) chain structure. The chains are arranged in an alternate up−down−up mode, with all the pyridyl rings involved in π···π stacking interactions to afford a 3D structure which consists of hexagonal channels along the c-axis. [Hg2(L2)2Br4]·H2O (17) and [Hg2(L2)2I4]·H2O (18) have binuclear coordination moieties, which are linked with water molecules by hydrogen bonds to form 1D structures. From these results, it is demonstrated that the structures of the complexes and the coordination modes of L1 and L2 are strongly dependent on the metal cations and the anions. The Hg(II) atoms in these complexes have tetrahedral coordination environments, whereas the Cd(II) centers have octahedral coordination geometries when Cl− is used as the anion, affording 3D and 2D coordination networks. The photoluminescence of L1, L2, and the complexes measured in the solid state at room temperature indicated that the emission colors vary from violet to yellow, and the emission intensity varies to a large extent, which can be rationalized by the contribution of a conflicting coordination effect and the heavy atom effect.
Co-reporter:Quan-Guo Wang, Yong-Shu Xie, Fan-Hua Zeng, Seik-Weng Ng, Wei-Hong Zhu
Inorganic Chemistry Communications 2010 Volume 13(Issue 8) pp:929-931
Publication Date(Web):August 2010
DOI:10.1016/j.inoche.2010.04.028
A novel coordination polymer [(ZnTPP)3 L1]n·(DMF)2n 1 (ZnTPP = zinc(II) tetraphenylporphyrinate) has been hydrothermally synthesized from a tetrapyridyl ligand N,N,N′,N′-tetra(4-pyridyl)-1,4-phenylenediamine (L1) and characterized by elemental analysis, IR, and single-crystal X-ray diffraction analyses. In the crystal, L1 utilizes all four pyridyl N atoms to coordinate at the axial positions of two different ZnTPP units. The first utilizes two axial positions for coordination, and the second coordinates at only one of the axial positions. Thus, the former ZnTPP units and two pyridyl nitrogens of L1 ligands are linked alternately to afford a zigzag chain, and two of the latter porphyrin units are appended to both sides of each repeating unit of the zigzag chain by coordination to the remaining two nitrogens of each L1 ligand. Interestingly, the appended porphyrins form two straight lines at both sides of the zigzag chain by the linkage of π∙∙∙π interactions between the phenyl rings. Finally, a triple chain is formed. The solid state emission of 1 is also studied.A novel coordination polymer [(ZnTPP)3 L1]n·(DMF)2n (1) has been synthesized from a tetrapyridyl ligand L1 and tetraphenyl porphyrinato zinc(II). 1 has a triple chain structure, formed by the linkage of π∙∙∙π interactions in addition to the coordination of the pyridyl nitrogen atoms at the axial positions of ZnTPP.
Co-reporter:Quanguo Wang;Yubin Ding;Weihong Zhu
Frontiers of Chemistry in China 2010 Volume 5( Issue 2) pp:162-165
Publication Date(Web):2010 June
DOI:10.1007/s11458-010-0105-9
A supramolecular fluorescent sensor of F− based on intermolecular energy transfer is described. The maximum absorption wavelength of a pyrrolic compound 1 is 472 nm, which is coincident with the emission wavelength of a dipyridylamine-anthracene compound 2. In the CH2Cl2 solution of 1 and 2, the fluorescence of 2 was quenched because of the presence of intermolecular energy transfer from 2 to 1. When F− was added to this solution, the absorption maximum wavelength of 1 shifted from 472 to 594 nm due to a deprotonation process. Simultaneously, the fluorescence of 2 was recovered because of the interruption of the intermolecular energy transfer. Based on these observations, the combination of 1 and 2 can be regarded as a novel supramolecular fluorescence enhancing F− probe.
Co-reporter:Yongshu Xie, Jia Ni, Fakun Zheng, Yong Cui, Quanguo Wang, Seik Weng Ng and Weihong Zhu
Crystal Growth & Design 2009 Volume 9(Issue 1) pp:118
Publication Date(Web):December 2, 2008
DOI:10.1021/cg7012073
Three tetranuclear complexes [Cu4(H2L1)4]·10H2O (1), [Ni4(H2O)3(H2L1)3(OH)]NO3·6H2O (2) and [Zn4(H2L1)4]·2MeOH·2H2O (3) and two binuclear complexes [Cu2(H3L1)2(NO3)2] (4) and [Cu2(H3L2)2Cl2](ClO4)2·2H2O (5) have been synthesized from two potentially pentadentate hydroxyl-rich ligands H4L1 and H3L2 (H4L1 = tris(hydroxymethyl)(2-hydroxybenzylamino)methane, and H3L2 = tris(hydroxymethyl)(2-pyridylamino) methane). X-ray analyses reveal that complexes 1, 2, and 3 have cubane core structures. For 1, ten lattice water molecules are linked by twelve hydrogen bonds, forming an extremely unusual adamantanoid (H2O)10 cluster, which is linked to two tetranuclear moieties by octadruple hydrogen bonds. For 2, four water dimers are bridged by two nitrates, giving a [(H2O)8(NO3)2]2- cluster. 4 has a bis(μ2-phenoxo)-bridged dicopper(II) structure with the binuclear species linked by multiple hydrogen bonds, affording a ladder-like structure. 5 has a bis(μ2-Cl)-bridged dicopper(II) structure with the binuclear moieties linked by π−π interactions and hydrogen bonds, affording a 2D network. In these complexes, the hydroxyl-rich ligands coordinate in dianionic, monoanionic or neutral forms, with one of the alkoxyl groups of each ligand left noncoordinated and open for intermolecular interactions, resulting in the stabilization of various water clusters and the formation of various supramolecular assemblies. Magnetic measurements reveal that, for 1 and 2, antiferromagnetic and ferromagnetic couplings coexist, thus resulting in interesting nonzero spin ground state. The ferromagnetic behavior of 1 can be ascribed to the nearly perpendicular arrangement of dx2−y2 magnetic orbitals of Cu(II) centers with the dihedral angle of 84.06(3)° between the Cu(II) equatorial planes. 4 shows a strong antiferromagnetic interaction. On the other hand, 5 shows a ferromagnetic interaction between copper(II) centers. Magneto-structural correlations have been discussed.
Co-reporter:Quanguo Wang, Yongshu Xie, Yubin Ding, Xin Li and Weihong Zhu
Chemical Communications 2010 - vol. 46(Issue 21) pp:NaN3671-3671
Publication Date(Web):2010/04/16
DOI:10.1039/C001509A
The combination of pyrrole and hemiquinone units produced a novel prototype of efficient colorimetric fluoride sensors, and the presence of the tautomerism effect provides additional means of modulating the sensing behavior.
Co-reporter:Yubin Ding, Yongshu Xie, Xin Li, Jonathan P. Hill, Weibing Zhang and Weihong Zhu
Chemical Communications 2011 - vol. 47(Issue 19) pp:NaN5433-5433
Publication Date(Web):2011/04/11
DOI:10.1039/C1CC11493J
Di- and tripyrrin sensors D1–D4 exhibit CHEF-type fluorescence enhancement by factors up to 72 upon addition of 1 equiv. Zn2+, with tunable emission colours between green (D1) and red (D4).
Co-reporter:Yongshu Xie, Yubin Ding, Xin Li, Cheng Wang, Jonathan P. Hill, Katsuhiko Ariga, Weibing Zhang and Weihong Zhu
Chemical Communications 2012 - vol. 48(Issue 94) pp:NaN11515-11515
Publication Date(Web):2012/10/23
DOI:10.1039/C2CC36140J
2,2′-Dipyridylamine and anthracene units were linked to afford highly emissive compounds whose Cu2+ ensembles were developed as effective fluorescence turn-on CN− probes.
Co-reporter:Yubin Ding, Tong Li, Weihong Zhu and Yongshu Xie
Organic & Biomolecular Chemistry 2012 - vol. 10(Issue 21) pp:NaN4207-4207
Publication Date(Web):2012/03/27
DOI:10.1039/C2OB25297J
Cyanide sensing has attracted increasing interest due to its toxicity and wide use in industrial activities. Herein, we developed three colorimetric cyanide sensors by the modification of the α-position of a dipyrrin chromophore with various carbonyl groups, namely, C6F5CO, C6H5CO and CHO for 1, 2 and 3, respectively. In dichloromethane, these sensors respond to both CN− and F− with distinct colour changes. UV-Vis, 1H NMR and HRMS measurements imply a two-process interaction between the sensors and CN−. Initially, CN− forms a hydrogen bond with the NH moiety, and then it attacks the carbonyl group of the sensors via a nucleophilic addition reaction. In contrast, in aqueous systems, only cyanide induced vivid solution colour changes from light yellow to pink via nucleophilic addition reactions. The CN− detection limits reach a micromolar level of 3.6 × 10−6 M, 4.2 × 10−6 M and 7.1 × 10−6 M for 1, 2 and 3, respectively. In view of the easy synthesis and the highly selective recognition of CN− with vivid colour changes, 1–3 may be developed as a novel and promising prototype of selective and sensitive colorimetric cyanide sensors.
Co-reporter:Jonathan P. Hill, Navaneetha K. Subbaiyan, Francis D’Souza, Yongshu Xie, Satyajit Sahu, Noelia M. Sanchez-Ballester, Gary J. Richards, Toshiyuki Mori and Katsuhiko Ariga
Chemical Communications 2012 - vol. 48(Issue 33) pp:NaN3953-3953
Publication Date(Web):2012/02/27
DOI:10.1039/C2CC30712J
Tetrapyrazinoporphyrazine substituted at its periphery with eight antioxidant 3,5-di-t-butyl-4-hydroxyphenyl groups behaves as a turn-on fluorescent sensor for fluoride anions. Conversely, the precursor antioxidant-substituted 1,2-phthalonitrile was found to act in turn-off mode suggesting that the origin of the phenomenon lies at the phenolate-substituted 1,4-pyrazinyl moiety.
Co-reporter:Xi Sun, Yueqiang Wang, Xin Li, Hans Ågren, Weihong Zhu, He Tian and Yongshu Xie
Chemical Communications 2014 - vol. 50(Issue 98) pp:NaN15612-15612
Publication Date(Web):2014/10/22
DOI:10.1039/C4CC07963A
XS1–XS3 have been synthesized by introducing an auxiliary acceptor into D–π–A dyes for simultaneous filling up of both absorption valleys of porphyrin dyes at around 550 and 380 nm. Thus, panchromatic DSSCs with the highest efficiency of 10.75% were achieved by cosensitization. This work provides a strategy for designing cosensitizers for porphyrin dyes.
Co-reporter:Yubin Ding, Yunyu Tang, Weihong Zhu and Yongshu Xie
Chemical Society Reviews 2015 - vol. 44(Issue 5) pp:NaN1112-1112
Publication Date(Web):2015/01/22
DOI:10.1039/C4CS00436A
Metal ions and anions play important roles in many industrial and biochemical processes, and thus it is highly desired to detect them in the relevant systems. Small organic molecule based sensors for selective and sensitive detection of target ions show the advantages of low cost, high sensitivity and convenient implementation. In this area, pyrrole has incomparable advantages. It can be easily incorporated into linear and macrocyclic conjugated structures such as dipyrrins, porphyrins, and N-confused porphyrins, which may utilize the imino N and amino NH moieties for binding metal ions and anions, respectively. In this tutorial review, we focus on representative examples to describe the design, syntheses, sensing mechanisms, and applications of the conjugated oligopyrroles. These compounds could be used as colorimetric or fluorescent ion probes, with the advantages of vivid colour and fluorescence changes, easy structural modification and functionalization, and tunable emission wavelengths. Compared with normal porphyrins, simple di- and tripyrrins, as well as some porphyrinoids are more suitable for designing fluorescence “turn-on” metal probes, because they may exhibit flexible confirmations, and metal coordination will improve the rigidity, resulting in vivid fluorescence enhancement. It is noteworthy that the oligopyrrolic moieties may simultaneously act as the binding unit as well as the reporting moiety, which simplifies the design and syntheses of the probes.
Co-reporter:Kai Zhang, Mathew Savage, Xin Li, Yu Jiang, Masatoshi Ishida, Koki Mitsuno, Satoru Karasawa, Tatsuhisa Kato, Weihua Zhu, Sihai Yang, Hiroyuki Furuta and Yongshu Xie
Chemical Communications 2016 - vol. 52(Issue 29) pp:NaN5151-5151
Publication Date(Web):2016/03/10
DOI:10.1039/C6CC00707D
A rational and effective approach for synthesizing linear π-conjugated hexa-, hepta- and octapyrrins through the regioselective oxidative coupling of monoacylated tripyrrane and bilane is described. Depending upon the numbers of pyrrolic units, the geometry and properties of bis-copper(II) complexes could be systematically modulated.
Co-reporter:Yubin Ding, Tong Li, Xin Li, Weihong Zhu and Yongshu Xie
Organic & Biomolecular Chemistry 2013 - vol. 11(Issue 16) pp:NaN2692-2692
Publication Date(Web):2013/02/25
DOI:10.1039/C3OB40121A
Most reported Zn2+ probes suffer from the interference of background fluorescence originated from the conjugated structures of commonly utilized fluorophores. In this work, three novel meso-hydroxyl group substituted dipyrromethanes DPMOH1–DPMOH3 were synthesized and found to be colourless and nonfluorescent due to the interruption of the conjugated π system by an sp3 carbon between the two pyrrolic units. Interestingly, only the addition of Zn2+ to the solutions of DPMOH1–DPMOH3 promoted their oxidation to dipyrrin forms, and bright fluorescence “turn on” was observed due to the formation of corresponding dipyrrin complexes with the dipyrrin:zinc stoichiometry of 2:1. Zn2+ detection mechanism was investigated by UV-Vis, fluorescence, 1H NMR and HRMS analyses, which can be ascribed to the CHEF type fluorescence enhancement, resulting from good rigidity of the dipyrrin complexes. Hence, DPMOH1–DPMOH3 can be used as fluorescence turn-on Zn2+ probes with the advantage of no background fluorescence.
Co-reporter:Bin Chen, Gang Yu, Xin Li, Yubin Ding, Cheng Wang, Zhiwei Liu and Yongshu Xie
Journal of Materials Chemistry A 2013 - vol. 1(Issue 44) pp:NaN7417-7417
Publication Date(Web):2013/09/20
DOI:10.1039/C3TC31751J
Starting from two simple units of anthracene and 2,2′-dipyridylamine, a series of new luminescent compounds 1–8 were designed and synthesized by a combined strategy of changing the connection mode between the two units, extending the conjugation size, and introducing an additional electron donor. Photophysical properties of 1–8 were investigated and discussed on the basis of solvatochromic behaviour, theoretical calculations, crystal structure, and optimized structures. Interestingly, the emission wavelengths of these compounds could be successfully tuned from violet to red both in solutions and the solid-state, and prominent positive solvatochromism was observed for the compounds with a D–π–A framework. Consider compound 7 as an example, it shows peaks at 526 nm and 627 nm in cyclohexane and DMSO, respectively. Meanwhile, the quantum yield was decreased from 0.80 in cyclohexane to 0.12 in DMSO. The introduction of bulky groups was demonstrated to be effective for suppressing the aggregation effect and thus improving the solid state emission quantum yield. These results indicate that the combined structure modulation strategy offers a powerful tool for tuning the emission behaviour. To demonstrate the possibility of practical applications, 2 was employed as the emitting material for the fabrication of deep-blue organic light-emitting diodes (OLEDs), which showed a maximum external quantum efficiency of 2.2%. The CIE coordinates of (0.15, 0.08) are indicative of excellent blue color purity.
Co-reporter:Bin Chen, Yubin Ding, Xin Li, Weihong Zhu, Jonathan P. Hill, Katsuhiko Ariga and Yongshu Xie
Chemical Communications 2013 - vol. 49(Issue 86) pp:NaN10138-10138
Publication Date(Web):2013/09/05
DOI:10.1039/C3CC46008H
For the rational design of fluorescence “turn-on” cyanide probes, a general strategy is developed by introducing a dicyanovinyl group at the sterically demanding position of a large π framework.
Co-reporter:Bo Liu, Weihong Zhu, Yueqiang Wang, Wenjun Wu, Xin Li, Baoqin Chen, Yi-Tao Long and Yongshu Xie
Journal of Materials Chemistry A 2012 - vol. 22(Issue 15) pp:NaN7444-7444
Publication Date(Web):2012/03/08
DOI:10.1039/C2JM16804A
In the design of efficient sensitizers for dye-sensitized solar cells (DSSCs), it is vital to modulate the HOMO and LUMO orbitals by introducing suitable donor and acceptor groups. In this respect, triphenylamine has been extensively used as the donor group. Porphyrin has strong absorption in the UV-Vis range, which makes it a promising dye candidate. In addition, a porphyrin molecule contains eight β positions and four meso-positions, which may be conveniently utilized for introducing multiple donor and acceptor moieties. In this work, various numbers of triphenylamine and trimethoxyphenyl groups are introduced to the porphyrin meso-positions as electron donors, with the aim to systematically modulate the energy levels and investigate the effect on the efficiency of the DSSCs. The HOMO–LUMO energy gaps remain almost constant irrespective of the donor groups, thus, the variation of the donors leads to a contradictory effect on the processes of electron injection and dye regeneration. In the case of the zinc porphyrin with two triphenylamine units and one trimethoxyphenyl group as the electron donors (M3T2P), moderate and well-matched HOMO and LUMO energy levels are observed, thus affording high efficiencies for both the electron injection and the dye regeneration processes. The overall conversion efficiencies (η) of the DSSCs based on these dyes lie in the range of 2.70–5.45%, with the optimized performance achieved by M3T2P, which can be rationalized by the efficient electron injection and dye regeneration processes, and the long electron lifetime, as demonstrated by the electrochemical impedance spectroscopy measurements. These results provide further insights into the strategy for elevating the efficiencies of DSSCs, especially those based on porphyrins, simply by modulating the electron donor groups.
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