Tao Wang

We report herein the design and synthesis of a class of dipolar and quadrupolar carbazole- and/or triphenylamine-based D–π–D multiarylamino dyes (DCzBus), which contain a 1,4-butylidene biscarbazole core linked to hexylcarbazole or triphenylamine peripheral groups through alkynyl bridges. For multiarylamino groups and bulk conjugated structure, DCzBus all show strong one-photon and two-photon excited blue-violet fluorescence emission bands from 350 to 480 nm. Especially, DCzBus with triphenylamine peripheral groups have higher fluorescence quantum efficiency and longer fluorescence lifetime than those with carbazole peripheral groups. Stern–Volmer measurement indicated that these DCzBus could show fluorescence quenching response to benzyl peroxide through the photo-induced electron transfer mechanism. The fluorescence quantum yield and lifetime and non-planar conformation of DCzBus could significantly affect their photo-induced electron transfer process with benzoyl peroxide. Two-photon excited fluorescence quenching under different excited laser wavelengths was observed, which indicated that the D–π–D multiarylamino dyes designed in this study are potentially useful two-photon-induced fluorescence probes.

Conjugated phenothiazine oxime esters as free radical photoinitiators

Co-reporter:Xiaoyu Ma;Renquan Gu;Liujian Yu;Weixiang Han;Jie Li;Xiuyan Li

Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 39) pp:6134-6142

Publication Date(Web):2017/10/10

DOI:10.1039/C7PY00797C

Three novel phenothiazine-substituted oxime esters (Ph-PTZ-OXE, TPA-PTZ-OXE and CZ-PTZ-OXE) applicable to visible laser diodes (405 nm and 455 nm) were successfully designed and synthesised. The introduction of phenothiazine groups in oxime esters led to a significant redshift in UV-vis absorption, thereby making the oxime esters suitable for promoting photopolymerization under visible light irradiation. Upon exposure to the irradiation of a laser diode at 405 nm and 455 nm, the three oxime esters showed high polymerization efficiency in the free radical polymerization of tripropylene glycol diacrylate (TPGDA). The oxime ester system was paired with iodonium salt (ION) and exhibited high efficiency in promoting free radical polymerization. The photochemical mechanisms were established from the fluorescence spectrum, cyclic voltammograms (CV) and electron spin resonance (ESR) data. The iminyl radical is characterized by two quartets centered at 323.1 mT and 324.4 mT. The benzoyloxyl radical gives rise to two broad peaks at 320.9 mT and 336.7 mT, with a high g value characteristic of oxygen-centered radicals.

Carbazole-based compounds containing aldehyde and cyanoacetic acid: optical properties and applications in photopolymerization

Co-reporter:Hussain Ahmed Abro;Tengfei Zhou;Weixiang Han;Tanlong Xue

RSC Advances (2011-Present) 2017 vol. 7(Issue 87) pp:55382-55388

Publication Date(Web):2017/12/01

DOI:10.1039/C7RA11887B

Carbazole-based dyes containing aldehyde and cyanoacetic acid groups were synthesized through Sonogashira coupling and Knoevenagel reactions. These compounds included 6-((4-(diphenylamino)phenyl)ethynyl)-9-ethyl-9H-carbazole-3-carbaldehyde (CCC), 9-ethyl-6-((9-ethyl-9H-carbazol-3-yl)ethynyl)-9H-carbazole-3-carbaldehyde (TCC), (E)-2-cyano-3-(9-ethyl-6-((9-ethyl-9H-carbazol-3-yl)ethynyl)-9H-carbazol-3-yl)acrylic acid (CCN) and (E)-2-cyano-3-(6-((4-(diphenylamino)phenyl)ethynyl)-9-ethyl-9H-carbazol-3-yl)acrylic acid (TCN). Density functional theory (DFT) calculations revealed these structures to be coplanar-conjugated molecular and uniform in shape. The UV spectra showed three main absorption peaks from 240 nm to 400 nm, indicating π–π* and n–π* electron transitions. The calculated vertical singlet excitation energy was within the range of n–π*. This finding was confirmed based on the acceptor results in reduced highest occupied molecular orbital-lowest unoccupied molecular orbital gap by launching cyanoacetic acid. These functional compounds could be used as dyes/photosensitizers.

D–D–A dyes with phenothiazine–carbazole/triphenylamine as double donors in photopolymerization under 455 nm and 532 nm laser beams

Co-reporter:T. F. Zhou, X. Y. Ma, W. X. Han, X. P. Guo, R. Q. Gu, L. J. Yu, J. Li, Y. M. Zhao and Tao Wang

Polymer Chemistry 2016 vol. 7(Issue 31) pp:5039-5049

Publication Date(Web):18 Jul 2016

DOI:10.1039/C6PY00918B

In order to enhance electron-donating ability and absorptivity in the visible region of the spectrum, four novel organic dyes (CPC, TPC, CPN and TPN) with carbazole–phenothiazine or triphenylamine–phenothiazine as double electron donors (D), and cyanoacrylic acid or an aldehyde group as the electron acceptor (A) have been designed and synthesized. The dyes exhibit charge transfer properties in the ground and excited states and absorb strongly in the spectral range of 380–550 nm. Upon exposure to irradiation of a laser diode at 455 and 532 nm, the dyes together with an iodonium salt induced high polymerization efficiency in the cationic polymerization of bisphenol-A epoxy resin A (DGEBA) and free radical polymerization of tripropylene glycol diacrylate (TPGDA). An electron-transfer photosensitization mechanism was established based on steady-state photolysis experiments, theoretical calculations of molecular orbitals, and electrochemical analysis. Our results showed that these dyes would have extensive application in photopolymerization promoted by soft visible light.

Thiophene-substituted phenothiazine-based photosensitisers for radical and cationic photopolymerization reactions under visible laser beams (405 and 455 nm)

Co-reporter:Pengjie Chao, Renquan Gu, Xiaoyu Ma, Tao Wang and Yuming Zhao

Polymer Chemistry 2016 vol. 7(Issue 32) pp:5147-5156

Publication Date(Web):21 Jul 2016

DOI:10.1039/C6PY01095D

Six new thiophene-substituted phenothiazine-based photosensitizers (ThPTZs) applicable to different visible laser diodes (405 nm and 455 nm) have been synthesized successfully via the Suzuki–Miyaura coupling reaction. The presence of thiophene groups in these compounds led to significantly redshifted UV-Vis absorption, making them suitable for promoting photopolymerization under visible light irradiation. Paired with bis(4-methylphenyl) iodonium hexafluorophosphate (ION), the ThPTZ systems exhibited high efficiency in promoting the ring-opening polymerization of epoxides and radical polymerization of acrylates in air using very soft laser diodes at 405 nm and 455 nm as the light sources. The detailed photochemical mechanisms have been studied by steady-state photobleaching, fluorescence spectroscopy and cyclic voltammetry analyses.

Synthesis and Characterization of Novel 1,4-Bis(carbazolyl)benzene Derivatives with Blue-Violet Two-Photon-Excited Fluorescence

Co-reporter:Baodong Zhao, Xiaoqin Jia, Jiqiang Liu, Xiaoyu Ma, Huiqing Zhang, Xiaoning Wang, and Tao Wang

Industrial & Engineering Chemistry Research 2016 Volume 55(Issue 6) pp:1801-1807

Publication Date(Web):January 27, 2016

DOI:10.1021/acs.iecr.5b04501

Novel fluorescent two-photon absorption molecules containing bis(carbazolyl)benzene as the central unit and phenylethynyl moieties as peripheral groups (Cz-Ps) are synthesized and characterized. In these molecules, two carbazolyl moieties are linked with benzene at the 9-position and synthesized by a concise process involving nucleophilic substitution between the cyclopentadienyliron complexes of dichloroarenes and phenylethynyl carbazole, followed by photolysis. The optimal structures of Cz-Ps reveal that two carbazolyl rings linked by a benzene ring are not planar. This feature prevents the electron conjugation of the molecule from extending throughout the whole molecule and allows Cz-Ps to realize blue-violet emissions and high fluorescence quantum yield. With increasing number of conjugated phenylacetylene structures in Cz-Ps, the maximal absorption and emission peaks were red-shifted. The quadrupolar compound DMoCz-P shows strong one-photon and two-photon activities. The resulting molecules are also thermally stable with high glass transition temperatures due to the rigid bicarbazole central unit. This work has demonstrated that using bis(carbazolyl)benzene as central building block could enhance two-photon absorption (TPA) performance and also provides a possible general synthetic strategy for a series of bis(carbazolyl)benzene derivatives, which would advance the understanding of the rational design of new organic optical materials.

Aromatic amine–sulfone/sulfoxide conjugated D–π-A–π-D-type dyes in photopolymerization under 405 nm and 455 nm laser beams

Co-reporter:Mengqiang Wang, Xiaoyu Ma, Jinghua Yu, Xiaoqin Jia, Dandan Han, Tengfei Zhou, Jinliang Yang, Jun Nie and Tao Wang

Polymer Chemistry 2015 vol. 6(Issue 24) pp:4424-4435

Publication Date(Web):11 May 2015

DOI:10.1039/C5PY00502G

Based on a D–π-A–π-D structural strategy, six novel dyes (Cz–SO, Cz–SO2, TA–SO, TA–SO2, PTZ–SO, and PTZ–SO2) containing triphenylamine/phenothiazine/carbazole as electron donors and sulfone/sulfoxide as electron acceptors are prepared and incorporated into a photoinitiating system, together with iodonium salt (ONI). The one- and two-photon photophysical properties of these dyes were studied. The UV-vis spectra showed red-shifts of 51 and 75 nm from N-ethyl carbazole (CZ) to Cz–SO and Cz–SO2. Similar red-shifts were found in the other dyes. The two-photon excited fluorescence (TPEF) spectra in the range 700–880 nm were recorded and it was found that these dyes present a clear two-photon absorption (TPA). Among them, PTZ–SO2 possesses the maximum TPA cross-section, which is 2465.5 GM. Ring-opening cationic polymerization of epoxides and free radical polymerization of acrylates upon exposure to very soft irradiation of laser diodes at 405 nm and 455 nm were performed using ONI/dyes initiating systems. Compared with the well-known camphorquinone-based systems, the combinations of the obtained dyes with iodonium salt exhibit higher polymerization efficiency. The results from photobleaching and electrochemical experiments show that these dyes could photosensitize ONI through photoinduced charge transfers. Owing to their higher polymerization efficiency and large TPA cross-section, these dyes would have extensive application prospects in the fields of photopolymerization by soft visible light irradiation sources and two-photon polymerization (TPP).

Novel phosphorus–nitrogen–silicon flame retardants and their application in cycloaliphatic epoxy systems

Co-reporter:Pengjie Chao, Yongjie Li, Xiaoyu Gu, Dandan Han, Xiaoqin Jia, Mengqiang Wang, Tengfei Zhou and Tao Wang

Polymer Chemistry 2015 vol. 6(Issue 15) pp:2977-2985

Publication Date(Web):04 Mar 2015

DOI:10.1039/C4PY01724B

To solve the incompatibility of flame retardants with epoxy resin, two novel phosphorus–nitrogen–silicon flame retardants (DPP-Si and PSAP) containing active hydroxyl groups were obtained via a simple and efficient synthesis. Both of the obtained flame retardants were characterized via FTIR, 1H NMR, and 31P NMR. Flame retardant epoxy composites (FR-Ep) were prepared with different contents of DPP-Si and PSAP in 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (ERL4221), and cross-linked by UV-radiation and thermal curing. The influence of DPP-Si and PSAP on the flame-retardant properties of FR-Ep was investigated through limiting oxygen index (LOI) and vertical burning tests (UL-94) respectively, the results show that the LOI of the FR-Ep containing 15 wt% of either DPP-Si or PSAP was about 27.6%, and attained a V-1 rating, whereas pure epoxy resin has an LOI of 20.5%. The microstructures of the char were investigated by scanning electron microscopy (SEM), the SEM results indicated that the residual char of the FR-Eps after burning have compact and coherent appearance, which plays an important role in the excellent thermal stability and improves the flame retardancy of FR-Ep by means of isolating fire sources and cutting off from oxygen.

A synergistic effect of a ferrocenium salt on the diaryliodonium salt-induced visible-light curing of bisphenol-A epoxy resin

Co-reporter:Yu Chen, Xiaoqin Jia, Mengqiang Wang and Tao Wang

RSC Advances 2015 vol. 5(Issue 42) pp:33171-33176

Publication Date(Web):02 Apr 2015

DOI:10.1039/C4RA16077K

The interactions of diaryliodonium and ferrocenium (FC) salts during photopolymerization under visible light were systematically studied. Spectroscopic, electrochemical, and calculation results indicate that electron transfer occurs between diaryliodonium and FC salts and that FC can be used as a photosensitizer for diaryliodonium salt photoinitiation systems under visible light. Thus, the activity of a two-component photoinitiator system composed of different proportions of diaryliodonium and FC salts was investigated for induction of cationic polymerization of bisphenol-A epoxy resin A (DGEBA) and cationic/free radical hybrid polymerization of a DGEBA/tripropylene glycol diacrylate (TPGDA) mixture under visible light. Cationic polymerization of DGEBA achieved high epoxy conversion, while hybrid polymerization of DGEBA and TPGDA achieved synchronous curing. The proposed two-component photoinitiator system may meet the special needs of applications such as 3D printing. Hybrid polymerization may improve the performance of light-cured polymers.

Synthesis and optical properties of novel D–π–A–π–D type cationic cyclopentadienyliron complexes of arenes

Co-reporter:B. D. Zhao, G. L. Li, Y. Z. Shi, H. Q. Zhang and T. Wang

RSC Advances 2015 vol. 5(Issue 67) pp:54749-54756

Publication Date(Web):16 Jun 2015

DOI:10.1039/C5RA08989A

Diphenylethynyl chromophores were successfully introduced into the arene ligands of cationic cyclopentadienyliron complexes through nucleophilic substitution and Suzuki coupling reactions. Three novel cationic cyclopentadienyliron complexes with symmetrical di(4-methoxy-phenylethynyl) chromophores (CFSs) were obtained and completely characterized by IR, 1H NMR, 13C NMR, and MS. The linear and nonlinear optical properties of the obtained molecules were tuned using phenylethynyl linkages. The UV-Vis absorption spectra showed that increasing the conjugation by substituting phenylacetylene spacer resulted in a red shift in the absorption bands and a stronger absorption in CFSs than in the previously reported (η6-cumene)(η5-cyclopentadienyl)iron hexafluorophosphate (I-261). These cross-conjugated D–π–A–π–D type compounds also showed larger third-order nonlinear susceptibility than I-261.

Synthesis and optical properties of cationic cyclopentadienyl iron complexes with diphenylacetylene chromophores

Co-reporter:Yizhong Shi, Guanglei Li, Baodong Zhao, Yu Chen, Pengjie Chao, Huiqing Zhang, Xiaoning Wang, Tao Wang

Inorganica Chimica Acta 2015 Volume 427() pp:259-265

Publication Date(Web):1 March 2015

DOI:10.1016/j.ica.2015.01.007

•Six novel cationic cyclopentadienyl iron complexes with diphenylacetylene chromophore were prepared.•Bearing phenylacetylene resulted in a red shift in the UV–Vis absorption spectra.•Five cationic cyclopentadienyl iron complexes show large two-photon absorption (TPA) cross section.Cationic cyclopentadienyl iron complexes of arenes are applied in photopolymerization and photocatalysis because of their good photophysical and photochemical properties. In this study, a series of cationic cyclopentadienyl iron complexes with diphenylacetylene chromophores (Aky-Fc) was obtained via nucleophilic substitution and Suzuki coupling reactions. The linear and nonlinear optical properties of the obtained molecules were tuned by phenylethynyl linkages. The UV–Vis absorption spectra showed that increasing the conjugation by substituting phenylacetylene spacer resulted in a red shift in the absorption bands and much stronger absorption in Aky-Fc than in (η6-cumene) (η5-cyclopentadienyl) iron hexafluorophosphate (I-261). With the single-beam Z-scan technique, the nonlinear absorption of Aky-Fc showed that Aky-Fc (8), (9), and (10) had good nonlinear optical ability, and the two photon absorption (TPA) cross section σ was approximately 10 times that of I-261.The electrostatic potential figure and the single-beam Z-scan curve of 10 are shown here. 10 showed excellent nonlinear optical ability, and the two photon absorption (TPA) cross section σ was approximately 10 times that of (η6-cumene) (η5-cyclopentadienyl) iron hexafluorophosphate (I-261).

Synthesis and optical properties of two cationic cyclopentadienyliron complexes of arene containing the triphenylbutene structure

Co-reporter:Tao Wang;Jiqiang Liu;Junru Han;Guanglei Li

Research on Chemical Intermediates 2015 Volume 41( Issue 8) pp:5095-5108

Publication Date(Web):2015 August

DOI:10.1007/s11164-014-1591-z

Two novel cationic cyclopentadienyliron complexes of arene containing the triphenylbutene group (TPBE-Fc) were synthesized and characterized by IR, UV–visible, 1H NMR, and 13C NMR spectroscopy, and by MS. The optical properties of the compounds were studied by experimental and theoretical methods. Positive solvatochromism of the UV–visible absorption of TPBE-Fc on increasing the solvent polarity was observed experimentally. Quantum chemical calculations of the orbital energy, geometric structure, absorption spectra, and first hyperpolarizability (β) values of the TPBE-Fc were performed by use of density functional (DFT/B3LYP and TD-DFT) methods. The spectra observed experimentally were in good agreement with the calculated values. The calculated HOMO and LUMO energies revealed the presence in the compounds of charge transfer mediated by the metal center.

Synthesis and optical properties of a D–A–D cationic cyclopentadienyl iron complex containing double arylazo chromophores

Co-reporter:Jiqiang Liu;Xiaoqin Jia;Guanglei Li;Baodong Zhao

Research on Chemical Intermediates 2015 Volume 41( Issue 11) pp:8245-8255

Publication Date(Web):2015 November

DOI:10.1007/s11164-014-1888-y

A D–A–D cationic cyclopentadienyl iron complex containing double arylazo chromophores (Fc-diazo) with methoxyl group (Fc-diazo-OMe) was obtained via nucleophilic substitution and well characterized by IR, UV–visible, 1H NMR, and 13C NMR spectroscopy, and MS. UV–Vis absorption and nonlinear optical property of Fc-diazo-OMe were investigated by comparison of Fc-diazo with no methoxyl group (Fc-diazo-H). Quantum chemical calculations of the orbital energy, geometric structure of Fc-diazo-OMe, and Fc-diazo-H were conducted by using density functional methods at the B3PW91/Lanl2dz level. Charge transfer from the highest occupied molecular orbital to the lowest unoccupied molecular orbital was found based on density functional theory. The substitution of the methoxyl group greatly improves the NLO property of Fc-diazo. Fc-diazo-OMe shows effective two-photon absorption, coefficient and third-order nonlinear susceptibility for potential applications as optical materials, while Fc-diazo-H barely shows NLO ability.

Efficient Pd-Catalyzed Coupling Reaction of Cationic Cyclopentadienyliron Complexes of Chloro-substituted Arenes with Arylboronic Acid

Co-reporter:Jie Zhao, Shao Jin, Yunwo Weng, Yu Chen, and Tao Wang

Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 4) pp:1308-1312

Publication Date(Web):January 8, 2014

DOI:10.1021/ie403413r

Cationic cyclopentadienyliron complexes of chloro-substituted arenes were found to perform efficient Pd-catalyzed cross-coupling reactions with arylboronic acids under mild conditions. Using this method, some new cationic cyclopentadienyliron complexes of biaryl derivatives (Fc–Bi) were obtained with good yields. After a photolysis reaction of the obtained Fc–Bi, some biaryl derivatives were easily obtained. Results in the present study provided a practical route to the preparation of Fc–Bi and biaryl derivatives.

Flame retardancy effects of phosphorus-containing compounds and cationic photoinitiators on photopolymerized cycloaliphatic epoxy resins

Co-reporter:Yong-Jie Li;Xiao-Yu Gu;Jie Zhao;Peng Jiang;Jun Sun

Journal of Applied Polymer Science 2014 Volume 131( Issue 7) pp:

Publication Date(Web):

DOI:10.1002/app.40011

ABSTRACT

This study presents a promising ultraviolet (UV)-curable epoxy resin formulation with improved flame-retardant properties. The formulation is based on the cycloaliphatic epoxide 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (ERL4221) and a novel silicon, phosphorous containing flame-retardant additive. The additive, 1,3,5,7-tetramethyl-1,3,5,7-tetra 2-(6-oxido-6-H-dibenzo(c,e) (1,2)oxaphosphorin-6-yl) ethylcyclotetrasiloxane (DOPO-SiD), was synthesized by the addition reaction of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (D₄Vi) with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). Formulations containing the cycloaliphatic epoxy resin ERL4221 and the flame-retardant DOPO-SiD additive were prepared in various concentrations and crosslinked by UV irradiation. The effects of DOPO-SiD and photoinitiators, such as the cyclopentadienyl iron complex of carbazole (In-Fe) and diphenyl-(4-(phenylthiol) phenyl) sulfonium hexafluorophosphate (In-S), on the flame-retardant properties and thermal stabilities of UV-cured ERL4221/DOPO-SiD composites were investigated with limiting oxygen index, UL-94 vertical test, and thermogravimetric analysis, respectively. The results showed that DOPO-SiD can increase the thermal stabilities of the ERL4221/DOPO-SiD. The char yield was improved when DOPO-SiD and In-Fe were simultaneously used. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40011.

Efficient Synthesis of Arylated Carbazole from Cyclopentadienyliron Complexes

Co-reporter:Yu Chen, Dandan Han, Tao Wang, and Xiuyan Li

Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 10) pp:3646-3652

Publication Date(Web):February 26, 2013

DOI:10.1021/ie4000773

Arylated carbazoles are valuable intermediates in the preparation of organic functional materials. The present work addresses an improved process for the preparation of arylated carbazoles. This process involves a nucleophilic substitution between the cyclopentadienyliron complexes of chloroarenes and carbazole or hydroxyl carbazole, followed by photolysis of cyclopentadienyliron complexes of arylated carbazoles (Fc-carbazole). The described process combines two steps in good yields and is cost-effective, and thus, it is a practical route of preparation of arylated carbazoles. The purification strategy of arylated carbazoles was subjected to crystallization instead of column chromatography, which is very good for their industrial applications. The arylated carbazoles products were determined by Fourier transform infrared (FT-IR), liquid chromatography mass spectroscopy (LC-MS), and NMR.

Photo-Fenton reaction of supported cationic cyclopentadienyl iron complexes of arene and application as heterogeneous catalysts in photodegradation of dyes under visible light

Co-reporter:Yu Chen, Shao Jin, Jiqiang Liu, Baodong Zhao, Tao Wang

Inorganica Chimica Acta 2013 Volume 406() pp:37-43

Publication Date(Web):1 September 2013

DOI:10.1016/j.ica.2013.07.005

•The supported [CpFeAr]+ was carried out in photo-Fenton reaction.•[CpFeAr]+/SiO was used as an efficient heterogeneous catalyst.•An electron transfer occurs between [CpFeAr]+ and a dye.Cationic cyclopentadienyl iron complexes of arene ([CpFeAr]+) were successfully loaded on silica gel (SiO) by physical absorption. The supported [CpFeAr]+ ([CpFeAr]+/SiO) catalysts were characterized by SEM–EDX, FT-IR and UV–Vis spectra. The catalysts show strong and broad absorptions from 200 to 550 nm. [CpFeAr]+/SiO carries out an effective photo-Fenton reaction with H2O2 under visible light for the photodegradations of organic dyes. Nearly total decolorations of rhodamine B (RhB) and crystal violet (CV) dyes were achieved by using [CpFeAr]+/SiO as the heterogeneous catalyst. Hydroxyl radicals (OH) were found in the photodegradation system of [CpFeAr]+/SiO, H2O2 and dyes under visible light. The negative ΔGel values of CV/[CpFeAr]+ and RhB/[CpFeAr]+ systems indicate that the electron transfer processes for the dye/CpFe+Ar systems are thermodynamically allowed. The possible mechanism for the degradation process of organic dyes in photo-Fenton reaction of [CpFeAr]+/SiO with H2O2 is proposed.The supported [CpFeAr]+/SiOs are effective in the photo-Fenton reaction for the degradations of dyes under visible light.

UV spectroscopic studies and charge transfer properties of azobenzene-containing cyclopentadienyliron complexes of arenes: A combined experimental and density functional theoretical study

Co-reporter:Guang Lei Li, Ji Qiang Liu, Bao Dong Zhao, Tao Wang

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2013 Volume 104() pp:287-291

Publication Date(Web):March 2013

DOI:10.1016/j.saa.2012.11.062

This study investigates the UV–Vis absorption and fluorescence emission of newly synthesized (η6-4-(4-nitrophenylazo) phenoxyl benzene) (η5-cyclopentadienyl) iron hexafluorophosphate (Fc-azo). Quantum chemical calculations of the orbital energy, geometrical structure, absorption spectra, and first hyperpolarizability (β) values of the Fc-azo were carried out using density functional (DFT/B3LYP and TD-DFT) methods. Comparisons between hydroxyl azobenzene compound and Fc-azo were made. Results showed that the observed spectra were in good agreement with the calculated values. The positive solvatochromism of the UV–Vis absorption of Fc-azo upon the increase in solvent polarity from the experiment and the calculated HOMO and LUMO energies showed that charge transfer occurred within the molecule. Moreover, the change in electron distribution led to the improved β for Fc-azo.Graphical abstractHighlights► Cyclopentadienyliron unit is a strong electron-withdrawing group. ► Fc-azo possesses positive solvatochromic character. ► Charge transfer occurs within the molecule and leds to the improved β.

Cationic cyclopentadienyliron azo-complexes: Synthesis, spectroscopic characterization, and molecular structure

Co-reporter:Guanglei Li, Yu Chen, Junru Han, Hui Ye, Xiaoning Wang, Tao Wang

Dyes and Pigments 2012 Volume 94(Issue 2) pp:314-319

Publication Date(Web):August 2012

DOI:10.1016/j.dyepig.2012.01.013

Two novel cationic cyclopentadienyliron azo-complexes (Azo-Fc) were synthesized by the SNAr reaction of (η6-chlorobenzene) (η5-cyclopentadienyl) iron hexafluorophosphate (Fc-Cl) with 1-phenylazo-2-naphthol and 4-(4-nitrophenylazo)carbazole. They were characterized by IR, 1H NMR, 13C NMR, and MS. The UV–vis spectral characteristics of the azo-complexes were investigated in four organic solvents of different degrees of polarity. These synthesized azo-complexes exhibited a bathochromic shift of the visible absorption maxima with the increase in conjugating skeleton. The study of photochemical properties reveals that the azo-complexes showed good photostability and that photolysis was difficult to realize. The geometric structures of the azo-complexes were optimized on the basis of density function theory at the B3PW91/Lanl2dz level. The energy levels of their frontier molecular orbitals were obtained.Highlights► Two cationic cyclopentadienyliron azo-complexes (Azo-Fcs) were synthesized. ► Theses two complexes showed good photostability and strong absorption. ► Electron transfer occurs from HOMO to LUMO in Azo-Fcs by calculation.

UV-Curable Epoxy Silicone with a High Refractive Index and Self-Photosensitizing Effect

Co-reporter:Tao Wang, Hui Ye, Xianshun Zhang, and Jue Cheng

Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 49) pp:15832

Publication Date(Web):November 20, 2012

DOI:10.1021/ie302638g

The present work addresses a demand for cationically UV-curable optically transparent monomers and oligomers with high photopolymerization activity and high refractive indexes (RIs). Two novel kinds of epoxy silicones, carbazole-bound epoxy tetramethylcyclotetrasiloxane (Ep-Cz-Si) and carbazole-bound epoxy methylhydrogen silicone oil (Ep-Cz-SiO), were synthesized from 1,3,5,7-tetramethylcyclotetrasiloxane (D4H) and methylhydrogen silicone oil (HHSiO), respectively. Their structures were confirmed by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR) spectroscopy. Ep-Cz-Si and Ep-Cz-SiO show strong self-photosensitizing effects in photopolymerization and can be photoinitiated directly by a common onium salt photoinitiator under a high-pressure mercury lamp. The RIs of Ep-Cz-Si and Ep-Cz-SiO improve with increasing carbazole content. The photocured networks from Ep-Cz-Si and Ep-Cz-SiO show good thermal stabilities.

Investigation of thermal instability of benzoyl peroxide in the presence of carbazole and its derivatives

Co-reporter:Bao-Dong Zhao, Ping-Yu Wan, Ji-Qiang Liu, Jian-Guo Wang, Tao Wang

Thermochimica Acta 2012 Volume 543() pp:232-238

Publication Date(Web):10 September 2012

DOI:10.1016/j.tca.2012.05.029

Benzoyl peroxide (BPO), a commonly used organic peroxide, has caused many catastrophes. The thermal characteristics of BPO mixed with carbazole and its derivatives are studied under non-isothermal conditions using differential scanning calorimetry (DSC). The kinetic parameters are obtained from analysis of the DSC curves by the Kissinger and Ozawa methods. Results indicated that when BPO is mixed with carbazole and N-alkyl carbazole, the hazard increased with lower activity energy (Ea) and exothermic peak (Tp). In the presence of N-alkyl substituted carbazole, the Tp for the decomposition of BPO is reduced to 75 °C, the decomposition procedure becomes more complex than that of pure BPO, and the exothermic decomposition peak in the DSC trace splits into two. In the presence of a cationic cyclopentadinyl iron carbazole complex, the decomposition hazard of BPO does not increase.Graphical abstract.Highlights▸ DSC was used to evaluate the thermal hazards of BPO with carbazole. ▸ When BPO is mixed with carbazole and N-alkyl carbazole, the hazard increased. ▸ N-alkyl carbazole make the Tp for the decomposition of BPO reduce to 75 °C.

Synthesis, spectroscopic characterization, and molecular structure of triphenyl butene derivatives containing a cyclopentadienyl iron unit

Co-reporter:Junru Han, Guanglei Li, Tao Wang

Inorganica Chimica Acta 2012 Volume 392() pp:374-379

Publication Date(Web):30 September 2012

DOI:10.1016/j.ica.2012.03.056

Three hydroxyl substituted triphenyl butene compounds (PHB) and their derivatives containing a cyclopentadienyl iron (PHB-Fc) unit were efficiently synthesized. The synthesis involved the McMurry cross-coupling reaction of appropriate ketones and the nucleophilic aromatic substitution (SNAr) reaction of (η6-chlorobenzene) (η5-cyclopentadienyl) iron hexafluorophosphate (Fc-Cl). The target compounds were characterized by IR, 1H NMR, 13C NMR, and MS. Their photophysical processes were investigated by UV–Vis absorption and fluorescence emission spectra in acetonitrile. The geometric structure was optimized based on the density functional theory at the B3LYP level. Theoretical results reveal that electron transfer occurred from the HOMO to the LUMO in PHB-Fc. The change in electron distribution subsequently led to the improved second-order optical susceptibility of PHB-Fc.Graphical abstractThree hydroxyl substituted triphenyl butene compounds containing a cyclopentadienyl iron unit were synthesized. UV–Vis absorption and fluorescence emission spectra and theoretical results were investigated.Highlights► Three hydroxyl substituted triphenyl butene compounds containing a cyclopentadienyl iron unit were synthesized. ► UV–Vis absorption and fluorescence emission spectra were investigated. ► Theoretical results reveal that electron transfer occurred from the HOMO to the LUMO in PHB-Fc.

Synthesis and cationic photopolymerization of phenyl epoxy-silicone monomers

Co-reporter:Hui Ye;Xian Shun Zhang;Yong Jie Li

Journal of Polymer Research 2012 Volume 19( Issue 12) pp:

Publication Date(Web):2012 December

DOI:10.1007/s10965-012-0019-y

Cationically photopolymerizable phenyl epoxy-silicone monomers (Ep-Ph-Si) with a high RI and high photopolymerization activity have been synthesized via sequential hydrosilylation reactions of 1,3,5,7- tetramethylcyclotetrasiloxane by attaching first styrene, followed by 4-vinyl-1-cyclohexene-1,2-epoxide in the presence of Lamoreaux catalyst. The content of benzene ring in the monomers was determined by 1HNMR; the epoxy value was examed by chemical titration. The RI of the obtained monomers showed that the benzene ring could improve the refractive indices (RIs) and the RIs of the phenyl epoxy-silicone monomers ranged from 1.50 to 1.52. The cationic photopolymerization of these monomers initiated by triarylsulfonium hexafluorophosphate (P-S) showed that phenyl epoxy-silicone monomers with little amount of benzene ring still exhibited high photopolymerization rate. Those properties are well suitable for the application in UV-curing optical coatings and encapsulation materials.

Synthesis and photochemical properties of cationic cyclopentadienyliron containing arylazo chromophores

Co-reporter:Guang-Lei Li, Hui Ye, Yu Chen, Bao-Dong Zhao, Tao Wang

Inorganic Chemistry Communications 2011 Volume 14(Issue 9) pp:1516-1519

Publication Date(Web):September 2011

DOI:10.1016/j.inoche.2011.06.011

Two kinds of cationic cyclopentadienyliron complexes containing arylazo chromophores (Azo-Fc) were synthesized through the nucleophilic aromatic substitution reactions of cyclopentadienyliron chlorobenzene complexes. The synthesized Azo-Fc was characterized by LC–MS, IR, and 1H NMR. The influence of substituents and the aryl ring on spectral data of the synthesized compounds is described. Unlike other cationic cyclopentadienyliron complexes, Azo-Fc hardly underwent photolysis and showed no photo-initiating abilities in the cationic polymerization under photo-irradiation; in addition, trans/cis isomerization by irradiation is possible at different wavelengths.Two kinds of cationic cyclopentadienyliron complexes containing arylazo chromophores which can undergo trans/cis isomerization by irradiation at different wavelengths were investigated.Highlights► Six new cationic cyclopentadienyliron complexes containing arylazo chromophores (Azo-Fc) were synthesized. ► UV–vis results showed that Azo-Fcs have strong absorption in the regions 300–450 nm. ► Unlike other cationic cyclopentadienyliron complexes, Azo-Fcs cannot undergo photolysis under a halogen lamp. ► Azo-Fcs can undergo reversible trans/cis isomerization by irradiation at different wavelengths.

A new visible light bimolecular photoinitiator system for free radical polymerization

Co-reporter:Yu Chen, Guanglei Li, Junru Han, Tao Wang

Journal of Photochemistry and Photobiology A: Chemistry 2011 Volume 222(2–3) pp:330-335

Publication Date(Web):15 August 2011

DOI:10.1016/j.jphotochem.2011.07.005

A new bimolecular photoinitiator system consisting of a ferrocenium salt (Fc) and N-methyl-2-pyrrolidone (NMP) is developed for free radical photopolymerization under visible light irradiation, which was delivered by a halogen lamp. Photopolymerization profiles of tripropylene glycol diacrylate (TPGDA) show that high conversion can be easily achieved. The processes associated with the Fc/NMP system are investigated by photochemical and electrochemical experiments. The results show that the photoinitiation mechanism of this bimolecular system could occur through charge transfers between Fc and NMP.Highlights► We develop a new bimolecular photoinitiator system consisting of a ferrocenium salt (Fc) and N-methyl-2-pyrrolidone (NMP) for free radical photopolymerization under visible light. ► The photoinitiation system of Fcs as free radical photoinitiators was simplified. ► The inherent problems of using dye as a photosensitizer was solved. ► Good initiation ability and high efficiency were found in this Fc/NMP system. ► An electron transfer process occurs between an Fc and NMP.

Absorption, fluorescence, and photoinitiating properties of the aromatic ethers and aromatic amines complexes of cyclopentadienyliron

Co-reporter:Guang-Lei Li;Guo-cheng Zhang;Yu Chen

Research on Chemical Intermediates 2011 Volume 37( Issue 8) pp:847-857

Publication Date(Web):2011 October

DOI:10.1007/s11164-011-0292-0

The aromatic ethers complexes of cyclopentadienyliron (O-CpFe) and aromatic amines complexes of cyclopentadienyliron (N-CpFe) were prepared by coupling several aniline derivatives and phenol derivatives with (η6-chlorobenzene) (η5-cyclopentadienyl) iron hexafluorophosphate through nucleophilic aromatic substitution reaction. The UV/vis absorption, fluorescence, and excitation spectra of the compounds were measured. The abilities of the photoinitiator in photopolymerizing the diglycidyl ether of the bisphenol-A epoxy oligomer under a halogen lamp were evaluated by near-infrared spectroscopy. The results show that the absorption of N-CpFe is higher than that of O-CpFe in the visible region. However, the photoinitiation ability of N-CpFe is lower than that of O-CpFe.

Visible light curing of bisphenol-A epoxides and acrylates photoinitiated by (η6-benzophenone)(η5-cyclopentadienyl) iron hexafluorophosphate

Co-reporter:Yu Chen;GuangLei Li;Huiqing Zhang

Journal of Polymer Research 2011 Volume 18( Issue 6) pp:1425-1429

Publication Date(Web):2011 November

DOI:10.1007/s10965-010-9547-5

Visible light curing of diglycidyl ether of bisphenol-A (DGEBA) epoxy oligomer and acrylate monomers photoinitiated by (η6-benzophenone)(η5-cyclopentadienyl) iron hexafluorophosphate (Fc-BP) under a halogen lamp were studied by near infrared spectroscopy. Fc-BP exhibited high efficiency in the radical photopolymerization of acrylate monomers, even without the presence of tertiary amines. Under the same light source, however, benzophenone did not show any photoinitiating ability. Fc-BP could also be used to photoinitiate the cationic polymerization of DGEBA. There was an obvious increase in the photopolymerization rate of DGEBA and a decrease in the induction period when benzoyl peroxide was used as a photosensitizer. The induction period at the beginning of DGEBA cationic polymerization was eliminated by introducing a certain amount of cycloaliphatic epoxy monomer ERL4221 as an active diluent. However, the final epoxy conversion was decreased when ERL4221 was used.

A novel ferrocenium salt as visible light photoinitiator for cationic and radical photopolymerization

Co-reporter:Meng Li, Yu Chen, Huiqing Zhang, Tao Wang

Progress in Organic Coatings 2010 Volume 68(Issue 3) pp:234-239

Publication Date(Web):July 2010

DOI:10.1016/j.porgcoat.2010.01.007

A novel hybrid photoinitiator for visible light photopolymerization, (η6-3-benzoyl-4-chlorodiphenylamine) (η5-cyclopentadienyl) iron hexafluorophosphate (Fc-NBP), was synthesized and studied. Its absorption in the UV and visible light regions showed much stronger activity than those of either the commercialized cationic photoinitiator I-261 or the conventional free radical photoinitiator benzophenone, especially above wavelengths of 350 nm. When exposed to visible light, the photoinitiator under study initiates both cationic polymerization and radical polymerization. The photoinitiator's abilities in the photopolymerization of acrylates and epoxides were evaluated by near infrared (NIR) spectroscopy. The results from NIR clearly indicate that Fc-NBP exhibited high efficiency in photopolymerizing acrylate monomers. In the same lamp, however, benzophenone showed no photoinitiating ability. The photopolymerization rate of the diglycidyl ether of the bisphenol-A epoxy (DGEBA) oligomer was found to be slower than that of acrylates when using Fc-NBP as the photoinitiator. This study shows that the polymerization of epoxide DGEBA can be speeded up by adding a photosensitizer benzoyl peroxide (BPO), but BPO and tertiary amines do not affect the free radical photopolymerization of tripropylene glycol diacrylate (TPGDA). We conclude by providing a possible photoinitiation mechanism.

Synthesis and photoactivity of novel cationic photoinitiators: (η6-Diphenylmethane) (η5-cyclopentadienyl) iron hexafluorophosphate and (η6-benzophenone) (η5-cyclopentadienyl) iron hexafluorophosphate

Co-reporter:Tao Wang, ZhiQ. Li, Ying Zhang, Mingb. Lu

Progress in Organic Coatings 2009 Volume 65(Issue 2) pp:251-256

Publication Date(Web):June 2009

DOI:10.1016/j.porgcoat.2008.11.011

Two novel cationic photoinitiators (η6-diphenylmethane) (η5-cyclopentadienyl) iron hexafluorophosphate (PhCH2PhFe+CpPF6−) and (η6-benzophenone) (η5-cyclopentadienyl) iron hexafluorophosphate (PhCOPhFe+CpPF6−), were synthesized, characterized, and studied. PhCH2PhFe+CpPF6− was prepared by straightforward synthetic techniques with ferrocene and diphenylmethane and PhCOPhFe+CpPF6− was synthesized from oxidation of diphenylmethane–cyclopentadienyliron salt. Their activity as cationic photoinitiators was studied using real-time infrared spectroscopy. The results obtained showed that PhCH2PhFe+CpPF6− and PhCOPhFe+CpPF6− are capable of photoinitiating the cationic polymerization of epoxy monomer directly on irradiation with long-wavelength UV light. Comparative studies also demonstrated that PhCH2PhFe+CpPF6− exhibited better efficiency than I-261 and PhCOPhFe+CpPF6−. DSC studies showed that PhCOPhFe+CpPF6− and PhCH2PhFe+CpPF6− photoinitiators in epoxides possess good thermal stability in the absence of light.

(6-N-alkylcarbazole) (5-cyclopentadienyl) iron hexafluorophosphate salts in photoinitiated and thermal epoxy polymerization

Co-reporter:Tao Wang;Zhiquan Li;Ying Zhang;Kafssi Hassan;Xiaoning Wang

Polymer Engineering & Science 2009 Volume 49( Issue 3) pp:613-618

Publication Date(Web):

DOI:10.1002/pen.21329

Abstract

(η6-Carbazole)(η5-cyclopentadienyl) iron hexafluorophosphate salts (CFS PF₆) are capable of photoinitiating cationic polymerization of epoxy monomers directly upon irradiation with long-wavelength UV light. To improve the solubility of CFS ferrocenium salts in epoxides, two CFS photoinitiators have been prepared: [cyclopentadiene-Fe-N-buylcarbazole] hexafluorophosphate (C4-CFS PF₆) and [cyclopentadiene-Fe-N-octylcarbazole] hexafluorophosphate (C8-CFS PF₆), bearing C4 and C8 alkyl chains, respectively, on the nitrogen atom. Studies with real-time infrared spectroscopy have shown that C4-CFS and C8-CFS photoinitiators exhibit high efficiency in polymerization of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (ERL-4221) epoxy monomer, but lower efficiency in polymerization of di(2,3-epoxypropyl)-3,4-epoxy-1,2-cyclohexanedioate (TDE-85) epoxy monomer. Benzoyl peroxide (BPO) sensitizer was very effective in improving the photoinitiating activities of CFS in polymerization of both ERL-4221 and TDE-85. DSC studies have shown that C4-CFS and C8-CFS photoinitiators can also be employed as thermal initiators for the cationic ring-opening polymerization of epoxides at moderate temperatures. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Synthesis and Characterization of Dicyclopentadiene – cresol Epoxy Resin

Co-reporter:Tao Wang;Ping Y. Wan;Qin P. Yu;Meng Yu

Polymer Bulletin 2008 Volume 59( Issue 6) pp:787-793

Publication Date(Web):2008 January

DOI:10.1007/s00289-007-0826-1

Starting from cresol, the synthesis of dicyclopentadiene (DCPD) – cresol epoxy resin was conducted. DCPD-containing phenol resin (DPR) was prepared via Friedel–Crafts alkylation, whereas DCPD-containing epoxy resin (DER) was prepared via epoxidation of DPR with epichlorohydrin. The chemical structure was characterized with FTIR and 1HNMR. Cure behaviors and glass transition temperature (Tg) of the resulting polymers were studied by differential scanning calorimeter (DSC). The results clearly indicated that cured polymer with a mixture of DCPD-cresol epoxy resin and diglycidyl ether of bisphenol A (E51) had higher Tg comparing with E51.

Several ferrocenium salts as efficient photoinitiators and thermal initiators for cationic epoxy polymerization

Co-reporter:Tao Wang, Jian W. Chen, Zhi Q. Li, Ping Y. Wan

Journal of Photochemistry and Photobiology A: Chemistry 2007 Volume 187(2–3) pp:389-394

Publication Date(Web):15 April 2007

DOI:10.1016/j.jphotochem.2006.11.007

A study of the photoinitiated and thermally initiated cationic polymerizations of epoxy oligomers with three ferrocenium salt photoinitiators bearing different arene ligands had been conducted. These photoinitiators were cyclopentadienyl-Fe-carbazole hexafluorophosphate ([Cp-Fe-carbazole]+PF6−), cyclopentadienyl-Fe-N-ethylcarbazole hexafluorophosphate ([Cp-Fe-n-ethylcarbazole]+PF6−) and cyclopentadienyl-Fe-aminonaphthalene hexafluorophosphate ([Cp-Fe-aminonaphthalene]+PF6−). They were synthesized by the reaction of ferrocene and the corresponding arenes. These ferrocenium salts were capable of photoinitiating the cationic polymerization of epoxide directly on irradiation with long-wavelength UV light. Comparative studies demonstrated that they were more effective photoinitiators than I-261 due to the strong absorption above 300 nm. Preliminary studies had shown that these photoinitiators could also be employed as thermal initiators for the cationic ring-opening polymerization of epoxides at moderate temperatures.

Carbazole-bound ferrocenium salt as an efficient cationic photoinitiator for epoxy polymerization

Co-reporter:Tao Wang;Bao Sh Li;Li X Zhang

Polymer International 2005 Volume 54(Issue 9) pp:

Publication Date(Web):23 MAY 2005

DOI:10.1002/pi.1837

The low absorption of cyclopentadienyl-Fe-cumene hexafluorophosphate (I-261) above 300 nm limits its utilization of longer wavelength emission from light sources. We report here the synthesis and photoactivity of a carbazole-bound ferrocenium salt, cyclopentadienyl-Fe-carbazole hexafluorophosphate ([Cp-Fe-carbazole]⁺PF₆⁻), which efficiently absorbs radiation between 300 and 400 nm. Its photoactivity is higher than that of I-261 as a cationic photoinitiator. When the photosensitizer benzoyl peroxide (BPO) is employed, [Cp-Fe-carbazole]⁺PF₆⁻ can obviously be sensitized. Two other ferrocenium salts with amine groups, cyclopentadienyl-Fe-aniline hexafluorophosphate ([Cp-Fe-aniline]⁺PF₆⁻) and cyclopentadienyl-Fe-p-methylaniline hexafluorophosphate ([Cp-Fe-p-methylaniline]⁺PF₆⁻) were also studied. As photoinitiators, they perform poorly and can not be sensitized by BPO. Copyright © 2005 Society of Chemical Industry

A study of the photoactivities and thermomechanical properties of epoxy resins using novel [cyclopentadien-Fe-arene]+PF6− photoinitiators

Co-reporter:Tao Wang, Li J Ma, Ping Y Wan, Jin P Liu, Fang Wang

Journal of Photochemistry and Photobiology A: Chemistry 2004 Volume 163(1–2) pp:77-86

Publication Date(Web):15 April 2004

DOI:10.1016/S1010-6030(03)00432-5

The cationic photopolymerization of epoxy resins, initiated by novel cyclopentadien-Fe-arene hexafluorophosphate ([cyclopentadien-Fe-arene]+PF6−), has been investigated. The influence of different photoinitiators and the presence of different epoxy monomers on the rate of photopolymerization and on the thermomechanical properties of the UV-cured film obtained had been studied. Using [cyclopentadien-Fe-biphenyl]+PF6− (CFB) as photoinitiator, the photoactivity increased obviously when cycloaliphatic epoxy monomer 3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexane carboxylate (ERL-4221) was added in epoxy resin (E44), but the film obtained is micro-heterogeneous. However, in spite of the lower activity, the film from glycidylether 1,2,3-(2,3-epoxypropyl)-glycidylether (EPON-812) + E44 is homogeneous. The film obtained from di(2,3-epoxypropyl)3,4-epoxy-1,2-cyclohexanedioate (TDE-85) + E44 possesses the highest glass transition temperature Tg. Photoinitiators can influence the properties of the resulting epoxy resins, including the rigidity, crosslink density, Tg and homogeneity. The resulting epoxy resin initiated by [cyclopentadien-Fe-toluene]+PF6− (CFT) with lower photoactivity got the highest crosslink density. Initiated by [cyclopentadien-Fe-diphenylether]+PF6− (CFD) and [cyclopentadien-Fe-anisole]+PF6− (CFA) with greater solubility, the compatibility of epoxy ERL-4221 and E44 can be improved.

Biphenyl Bis [(π-cyclopentadienyl) iron] Dication as an Efficient Cationic Photoinitiator for Epoxy Polymerization

Co-reporter:Tao WANG, Ying ZHANG, Xiaoling REN

Chinese Journal of Chemical Engineering (October 2008) Volume 16(Issue 5) pp:819-822

Publication Date(Web):1 October 2008

DOI:10.1016/S1004-9541(08)60162-7

Ferrocenium monocations as photoinitiators for cationic photopolymerization suffer from a limitation of low absorption and low reactivity under high-pressure Hg lamp. Here, a ferrocenium dication salt, biphenyl bis [(π-cyclopentadienyl)iron] hexafluorophosphate ([bis(Cp-Fe)-biphenyl] (PF6)2 was synthesized by the ligand exchange reaction between ferrocene and biphenyl. The chemical structure was characterized with FTIR and 1HNMR. The separation of ferrocenium monocation cyclopentadien-iron-biphenyl hexafluorophosphate ([Cp-Fe-biphenyl] PF6) and dication [bis(Cp-Fe)-biphenyl] (PF6)2 was carried out by column chromatography. The photoactivity of initiating photopolymerization of epoxide ERl4221 was studied as a cationic photoinitiator. [Bis(Cp-Fe)-biphenyl] (PF6)2 can efficiently absorb radiation above 300nm and its photoactivity is higher than that of its monocation.

A novel ferrocenium salt as visible light photoinitiator for cationic and radical photopolymerization

Co-reporter:Meng Li, Yu Chen, Huiqing Zhang, Tao Wang

Progress in Organic Coatings (July 2010) Volume 68(Issue 3) pp:234-239

Publication Date(Web):1 July 2010

DOI:10.1016/j.porgcoat.2010.01.007