Xiu-Feng Hou

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Name: 侯秀峰; XiuFeng Hou

Organization: Fudan University , China

Department: Department of Chemistry

Title: Professor(PhD)

TOPICS

Inorganic Chemistry

Organic Chemistry

Physical Chemistry

Water Oxidation

Chemicals
References

Bis-pyrazolyl functionalized mesoporous SBA-15 for the extraction of Cr(III) and detection of Cr(VI) in artificial jewelry samples

Co-reporter:Shu Liu, He-Zhen Cui, Yuan-Long Li, Ai-Ling Yang, Jin-Fan Zhang, Rui Zhong, Quan Zhou, Miao Lin, Xiu-Feng Hou

Microchemical Journal 2017 Volume 131() pp:130-136

Publication Date(Web):March 2017

DOI:10.1016/j.microc.2016.12.003

•A new bis-pyrazolyl group functionalized mesoporous silica was prepared.•The material selectively adsorbed Cr(III) ions in the presence of Cr(VI).•The material was used for preconcentration and determination of Cr(VI) coupled with ICP-AES.•Rapid detection of the Cr(VI) amounts was achieved for practical samples.A new method coupling novel solid-phase extraction (SPE) with inductively coupled plasma-atomic emission spectrometry (ICP-AES) was developed, based on the adsorbent prepared by modifying a strong-coordinating bis-pyrazolyl functional monomer onto mesoporous silica SBA-15. The adsorbent DPP@SBA-15 was characterized by a set of analytical techniques, as well as studied the optimized various experimental parameters such as pH, stripping agent, adsorption capacity and equilibrium adsorption time. This newly developed adsorbent material do exhibit good chemical and mechanical stability, satisfactory adsorption capacity (72.5 mg/g) and high selectivity for Cr(III). Consequently, the DPP@SBA-15 was utilized as SPE adsorbent for adsorption of Cr(III) and determination of Cr(VI). An excellent linearity was shown in the range of 1–20 μg/mL− 1 (R2 = 0.9999), and the limit of determination 0.028 μg/mL− 1. Furthermore, Cr(VI) released from artificial ring was successfully detected and considerable recoveries varying from 97.6 to 103.0% were attained.

Synthesis of o-Alkenylated 2-Arylbenzoxazoles via Rh-Catalyzed Oxidative Olefination of 2-Arylbenzoxazoles: Scope Investigation, Structural Features, and Mechanism Studies

Co-reporter:Quan Zhou, Jing-Fan Zhang, Hui Cao, Rui Zhong, and Xiu-Feng Hou

The Journal of Organic Chemistry 2016 Volume 81(Issue 24) pp:12169-12180

Publication Date(Web):November 15, 2016

DOI:10.1021/acs.joc.6b01836

2-Arylbenzazoles are promising molecules for potential applications in medicine and material areas. Efficient protocols for direct regioselective functionalization of 2-arylbenzoxazoles are in high demand. Herein, we disclose a general method for selective ortho-olefination of 2-arylbenzo[d]oxazoles with alkenes enabled by versatile Cp*Rh(III) in high yields. This protocol features broad functional group tolerance and high regioselectivity. Intermolecular competition studies and kinetic isotope effect experiments imply that the oxidative olefination process occurs via an electrophilic C–H activation pathway. The molecular structure of the m-fluoro-substituted olefination product confirms regioselective C–H activation/olefination at the more hindered site in cases where the meta F atom or heteroatom substituent existed. Apparent torsion angles were observed in the structures of mono- and bis-olefination products, which resulted in distinct different chemical shifts of olefinic protons. Additionally, two gram-scale reactions and further transformation experiments demonstrate that this method is practical for synthesis of ortho-alkenylated 2-arylbenzoxazole derivatives.

Selectivity Enhancement in Dynamic Kinetic Resolution of Secondary Alcohols through Adjusting the Micro-Environment of Metal Complex Confined in Nanochannels: A Promising Strategy for Tandem Reactions

Co-reporter:Hui Cao, Xiao-Han Zhu, Dong Wang, Zhenkun Sun, Yonghui Deng, Xiu-Feng Hou, and Dongyuan Zhao

ACS Catalysis 2015 Volume 5(Issue 1) pp:27

Publication Date(Web):November 7, 2014

DOI:10.1021/cs500988a

Dichloro(η6-p-cymene) (1-butyl-3-cyclohexyl-imidazolin-2-ylidene) ruthenium(II) (RuL) was synthesized and confirmed. Five heterogeneous catalysts with similar ruthenium cores were prepared by chemical immobilization method using various silica-based supports, including mesoporous silica SBA-15 of different pore sizes (Ru/Si-9, Ru/Si-8, and Ru/Si-7), nonporous silica particles (Ru/SiO2), and surface trimethylsilylated SBA-15 (Ru/SiMe). The dynamic kinetic resolution (DKR) of 1-phenylethanol, which includes metal–enzyme bicatalytic racemization in tandem with stereoselective acylation, gave product in 99% yield and 0% ee with homogeneous catalyst RuL, whereas the heterogeneous Ru/Si-8 exhibited high catalytic activity and enantioselectivity (up to 96% yield and 99% ee). The racemization and acylation abilities of different catalysts were analyzed. The influences of pore size and surface properties for heterogeneous catalysts were investigated, and the nanocage effect was found to be the key factor in stereoselectivity. The catalyst Ru/Si-8 performed well in reactions with various substrates and can be reused for at least seven times.Keywords: heterogeneous; homogeneous; immobilization; N-heterocyclic carbene; ruthenium; stereoselectivity; tandem reaction

Ligand effect in racemization and dynamic kinetic resolution of alcohols: Mechanism on cymene ruthenium complexes

Co-reporter:Hui Cao, Li-Hua Cai, Chen-Xi Wang, Xiao-Han Zhu, Zhi-Ming Li, Xiu-Feng Hou

Journal of Organometallic Chemistry 2015 Volume 775() pp:60-66

Publication Date(Web):1 January 2015

DOI:10.1016/j.jorganchem.2014.10.011

•Ligand effect on cymene Ru complexes-catalyzed racemization of sec-alcohols.•16- and 18-electron complexes bearing a weak ligand are excellent catalysts.•The dissociation of ligands to form vacant sites is crucial to 18-electron Ru complexes.•The optimized Ru complexes showed efficiency in alcohols DKR.A family of ruthenium complexes with different ligands was utilized in racemization of (R)-1-phenylethanol to investigate the potential influence of the ligands coordinated to the ruthenium center. Kinetic experiments showed that 16-electron cymene ruthenium complex with two chloro-bridge bonds and 18-electron ones with easily dissociative ligands are highly active for catalytic racemization of alcohols. Possible racemization mechanism for cymene ruthenium complexes was then proposed. Computational analysis of dissociation energy barrier, NBO analysis and reaction potential energy surface suggest that ligand-dissociation process is the vital step of the racemization catalyzed by cymene ruthenium complexes. Thereafter, these complexes were applied in the DKR of secondary alcohols to verify their efficiency and applicability.Kinetic profiles show that 16-electron cymene ruthenium complex and 18-electron ones with easily dissociative ligands are highly active for catalytic racemazition of alcohols. Computational analyses provide the evidence of ligand-dissociation process for 18-electron complexes to transform into 16-electron ones. The optimized Ru complexes showed good efficiency in alcohols DKR.

Activity and Recyclability Improvement Through Adjusting the Tethering Strategy for Pd-Catalyzed Suzuki–Miyaura Coupling Reaction of Aryl Chlorides

Co-reporter:Jing-Fan Zhang;Mingda Wang;Xu-Qing Guo;Shu Liu;Hui Cao

Catalysis Letters 2015 Volume 145( Issue 12) pp:2001-2009

Publication Date(Web):2015 December

DOI:10.1007/s10562-015-1609-1

Four mesoporous SBA-15-immobilized N-heterocyclic carbene (NHC) palladium catalysts with different nitrogen ligands were synthesized. The activity and recyclability of the catalysts were investigated in Suzuki–Miyaura cross-coupling reaction of typical aryl chlorides and arylboronic acids. Bulky NHC moiety was essential for efficiency, while tethering of nitrogen ligands on both support and NHC group could dramatically improve recyclability of the catalysts. The strategy offers an alternative strategy for designing highly efficient and recyclable immobilized catalysts.

Imino-N-Heterocyclic Carbene Palladium(II) Complex-Catalyzed Direct Arylation of Electron-Deficient Fluoroarenes with “On and Off” Chelating Effect Assistance

Co-reporter:Quan Zhou, Ya-Nong Wang, Xu-Qing Guo, Xiao-Han Zhu, Zhi-Ming Li, and Xiu-Feng Hou

Organometallics 2015 Volume 34(Issue 6) pp:1021-1028

Publication Date(Web):March 2, 2015

DOI:10.1021/om5004539

An imino-N-heterocyclic carbene palladium(II) complex with a bulky substituted group on the imino nitrogen was used to catalyze the direct arylation of electron-deficient fluoroarenes with aryl halides. A series of electron-poor substrates and aryl bromides could be coupled in good to excellent yields with satisfactory position selectivity (20 examples, up to 93%). These arylations could proceed at a relatively low temperature (80 °C, 20 examples, up to 95%) with mono-N-protected amino acid assistance. Some of them even gained higher yields than those at high temperature (110 °C). Otherwise, some aryl iodides can forge cross-coupling products in yields of nearly 30% under the optimized conditions. The rate profiles for arylation of electron-poor arenes were measured in the presence of the imino-N-heterocyclic carbene palladium(II) complex or Pd(OAc)2 as the catalyst, which showed that the former could keep catalytic activity for a longer time. Computational studies indicated that the imino nitrogen in the imino-N-heterocyclic carbene ligand can detach from and attach to the central metal in the catalytic cycle. Thus, the coordination site could be protected, and this effect may be responsible for decreasing the rate of palladium black formation.

Efficient and versatile transfer hydrogenation catalysts: Iridium (III) and ruthenium (II) complexes with 4-acetylbenzyl-N-heterocyclic carbenes

Co-reporter:Xiao-Han Zhu, Li-Hua Cai, Chen-Xi Wang, Ya-Nong Wang, Xu-Qing Guo, Xiu-Feng Hou

Journal of Molecular Catalysis A: Chemical 2014 Volume 393() pp:134-141

Publication Date(Web):1 November 2014

DOI:10.1016/j.molcata.2014.06.004

•New 4-acetylbenzyl NHC Ir and Ru complexes were synthesized.•The synthesized complexes showed efficient and versatile catalytic activity.•The transfer hydrogenation of ketones and N-alkylation of amines were investigated.•Intramolecular CH activition was observed in Ir-catalyzed transfer hydrogenation.New 4-acetylbenzyl-N-heterocyclic carbene ligands (1–4) have been used to synthesize iridium complexes 6–9 and ruthenium complex 10. All complexes were characterized by FT-IR, 1H and 13C NMR spectroscopy, elemental analysis, and in the case of 6, by X-ray diffraction studies. The catalytic performance of these iridium and ruthenium complexes for transfer hydrogenation of ketones and imines and N-alkylation of amines with primary alcohols were tested in a range of substrates, and showed high catalytic activity with 1 mol% catalytic loading. The neutral complex 8 with two acetyl groups also showed good catalytic efficiency under lower catalyst loading (0.01 mol%), with the maximum TON of 8000, while on the other hand, the cationic complex 9 with PF6− as counteranion showed good to excellent catalytic activity toward the N-alkylation of amines in a wide scope of substrates. We also found out that the Ir complex 6′ was formed through the intramolecular CH activition of 6 under the transfer hydrogenation conditions.A series of 4-acetylbenzyl N-heterocyclic carbene iridium and ruthenium complexes was developed and showed good to excellent catalytic activities toward both transfer hydrogenation of ketones and imines and N-alkylation of amines with alcohols. The iridium complex converted to an intramolecular CH activated one under the transfer hydrogenation conditions.

An Efficient and Recyclable Catalyst for N-Alkylation of Amines and -Alkylation of Secondary Alcohols with Primary Alcohols: SBA-15 Supported N-Heterocyclic Carbene Iridium Complex

Co-reporter:Dong Wang;Xu-Qing Guo;Chen-Xi Wang;Ya-Nong Wang;Rui Zhong;Xiao-Han Zhu;Li-Hua Cai;Zi-Wei Gao

Advanced Synthesis & Catalysis 2013 Volume 355( Issue 6) pp:1117-1125

Publication Date(Web):

DOI:10.1002/adsc.201200732

Abstract

A mesoporous silica (SBA-15)-supported pyrimidine-substituted N-heterocyclic carbene iridium complex was prepared and used as a catalyst for both environmentally friendly N-alkylation of amines and β-alkylation of secondary alcohols with primary alcohols. The structure of the supported iridium catalyst was characterized by Fourier transform infrared (FT-IR), ¹³C and ²⁹Si solid-state nuclear magnetic resonance (NMR), small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), iridium K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopic analyses which demonstrated that the coordination environment of the iridium centre and the 3-dimensional-hexagonal pore structure of SBA-15 were retained after the immobilization. The catalyst was found to be highly efficient for both kinds of reaction on a wide range of substrates under mild conditions. Moreover, the supported iridium catalyst was obviously superior to the unsupported one in the N-alkylation of aniline and β-alkylation of 1-phenylethanol with benzyl alcohol as substrate, which indicated that not only the iridium complex moiety but also the support material contributed to the catalytic activity of the supported iridium catalyst in these reactions. The supported iridium catalyst can be easily recycled by simple washing without chemical treatment, and exhibited excellent recycling performance without notable decrease in catalytic efficiency even after twelve test cycles for N-alkylation of aniline with benzyl alcohol, nine cycles for N-alkylation of different amines with different alcohols, and eight cycles for β-alkylation of 1-phenylethanol with benzyl alcohol, respectively.

Pd(OAc)2 catalyzed direct arylation of electron-deficient arenes without ligands or with monoprotected amino acid assistance

Co-reporter:Ya-Nong Wang, Xu-Qing Guo, Xiao-Han Zhu, Rui Zhong, Li-Hua Cai and Xiu-Feng Hou

Chemical Communications 2012 vol. 48(Issue 84) pp:10437-10439

Publication Date(Web):06 Sep 2012

DOI:10.1039/C2CC34949C

An efficient arylation of electron-poor arenes has been developed without the addition of external ligands or in the presence of a catalytic monoprotected amino acid which assisted the reaction to proceed under mild conditions. The meta-selectivity was observed under both conditions.

Palladium, iridium and ruthenium complexes with acyclic imino-N-heterocyclic carbenes and their application in aqua-phase Suzuki–Miyaura cross-coupling reaction and transfer hydrogenation

Co-reporter:Xu-Qing Guo, Ya-Nong Wang, Dong Wang, Li-Hua Cai, Zhen-Xia Chen and Xiu-Feng Hou

Dalton Transactions 2012 vol. 41(Issue 48) pp:14557-14567

Publication Date(Web):07 Nov 2012

DOI:10.1039/C2DT31989F

Palladium (4a–4c), iridium (5a–5c) and ruthenium (6a–6c) complexes have been prepared by in situ transmetalation from the corresponding silver complexes of acyclic imino-functionalized imidazolium chlorides [1-(Me)-imidazolium-3-{C(p-CH3–Ph)N(Ar)}]Cl (3) (Ar = 2,4,6-trimethylphenyl (3a), 2,6-diisopropylphenyl (3b) and phenyl (3c)) with [Pd(COD)Cl2], [Cp*IrCl2]2 or [Ru(p-cymene)Cl2]2, respectively. Iridium and ruthenium complexes, 5a[PF66]–5c[PF66], 6a[PF66]–6c[PF66], 6c[BF44], 6c[BPh44] and 6c[NTf222], were obtained directly from 5a–5c and 6a–6c through an anion-exchange process with KPF6, NaBF4, NaBPh4 and LiNTf2 (bis(trifluoromethylsulfonyl)imide lithium), respectively. All complexes were characterized by FT-IR, 1H and 13C NMR spectroscopy and elemental analysis. Crystal structures of 4a, 5a and 6c[NTf222] show that five-membered chelate ring is formed in these complexes by the coordination of the carbene carbon and the imino nitrogen atom, and the latter two are cationic compounds with Cl− and NTf2− as counteranion respectively. The catalytic performance of Pd complexes for Suzuki–Miyaura cross-coupling reactions in pure water and Ir and Ru complexes for transfer hydrogenation of ketones and imines was tested in a wide scope of substrates. Pd complex 4b with the largest steric hinder exhibited the best performance to gain moderate to excellent yields on catalyzing Suzuki–Miyaura cross-coupling of aryl chlorides and arylboronic acids in water. While in transfer hydrogenation of various ketones, all the Ir and Ru complexes were effective with good to excellent yields. Among all these complexes, 6c[PF66] was found most effective, and moderate yields could be obtained even in the transfer hydrogenation of imines. Moreover, different counteranions of Ru complexes are influential on catalyzing the transfer hydrogenation, with the sequence of PF6− ≈ BF4− > BPh4− > Cl− > NTf2−.

Effect of counterions and central cores of tripodal imidazolium salts on palladium-catalyzed Suzuki–Miyaura cross-coupling reactions

Co-reporter:Rui Zhong, Ya-Nong Wang, Xu-Qing Guo, Xiu-Feng Hou

Journal of Organometallic Chemistry 2011 696(9) pp: 1703-1707

Publication Date(Web):

DOI:10.1016/j.jorganchem.2010.12.012

Preparation of Mononuclear, Homodinuclear, and Heterotrinuclear Complexes by Salicylaldiminato-Functionalized Imidazolium Salt: Approach to Multifunctional Catalysts

Co-reporter:Rui Zhong;Ya-Nong Wang;Xu-Qing Guo;Dr. Zhen-Xia Chen ;Dr. Xiu-Feng Hou

Chemistry - A European Journal 2011 Volume 17( Issue 39) pp:11041-11051

Publication Date(Web):

DOI:10.1002/chem.201101557

Abstract

A salicylaldiminato imidazolium salt that bears both a Schiff base and imidazolium salt moiety was used to synthesize heterometallic compounds that could serve as multifunctional catalysts in certain reactions. The successful preparation of seven mononuclear compounds with a variety of transition metals (Pd, Ir, Ru, Zn, Ni) illustrated the high versatility of this class of ligands, which is crucial for the design of catalysts. Synthesis of homodinuclear compounds and heterotrinuclear compounds provided practical methods to connect multiple metal fragments through these ligands. The heterotrinuclear complex (Ni/Ir) was employed as a catalyst in the reaction of dehalogenation/transfer hydrogenation of halo-acetophenones. The preliminary catalytic study showed that this heterometallic species is more active than a combination of the corresponding monometallic species.

N-Heterocyclic Carbene Palladium Catalyzed Regioselective Oxidative Trifluoroacetoxylation of Unactivated Methylene sp3 C–H Bonds in Linear Alkyl Esters

Co-reporter:Xiu-Feng Hou, Ya-Nong Wang, and Inigo Göttker-Schnetmann

Organometallics 2011 Volume 30(Issue 21) pp:6053-6056

Publication Date(Web):October 11, 2011

DOI:10.1021/om200484g

Several N-heterocyclic carbene palladium catalyzed oxidation of nonactivated sp3 C–H bonds in linear primary and secondary trifluoroacetic acid esters have been developed. A high selectivity for the oxidation of the omega-1 carbon atom in trifluoroacetic acid n-propyl to n-octyl esters was realized by an appropriate choice of N-heterocyclic carbene palladium complexes.

Neutral Trinuclear Palladium(II) Metallocycles with Mixed Phosphane/Pyridine-4-thiolato Ligands and Their Catalytic Tests in SuzukiMiyaura Coupling Reactions

Co-reporter:Hui Wang;Rui Zhong;Xu-Qing Guo;Xiao-Yan Feng

European Journal of Inorganic Chemistry 2010 Volume 2010( Issue 1) pp:174-178

Publication Date(Web):

DOI:10.1002/ejic.200900895

Abstract

Three neutral trinuclear palladium(II) complexes [Ph₃PPdCl(μ-4-PyS)]₃ (1), [Cy₃PPdCl(μ-4-PyS)]₃ (2) and [(PhO)₃PPdCl(μ-4-PyS)]₃ (3) (4-PyS = pyridine-4-thiolate) were self-assembled from corresponding metal fragments [R₃PPdCl₂]₂ with lithium pyridine-4-thiolate (PySLi). The crystal structure reveals that complex 1 possesses a triangular macrocyclic structure in which the distances of Pd(1)···Pd(2), Pd(2)···Pd(3) and Pd(3)···Pd(1) are 7.764, 7.684 and 7.944 Å, respectively. An equilibrium between trinuclear complex 1 and mononuclear complex (Ph₃P)₂PdCl(4-PyS) (4) in solution through coordination and de-coordination of the PPh₃ ligand is confirmed by ³¹P NMR spectroscopy. A comparative study on the Suzuki–Miyaura coupling reaction showed that complexes 1 and 2 are more active precatalysts than [R₃PPdCl₂]₂ complexes without a PyS group.

Reactions of half-sandwich Co(III) complexes with heterocyclic thione ligands: η2-N, S coordination mode and formation of S–S bond

Co-reporter:Hui Wang, Xu-Qing Guo, Rui Zhong, Xiu-Feng Hou

Journal of Organometallic Chemistry 2009 694(9–10) pp: 1567-1570

Publication Date(Web):

DOI:10.1016/j.jorganchem.2009.01.040

Reactions of half-sandwich rhodium(III) and iridium(III) compounds with pyridinethiolate ligands: Mono-, di-, and tri-nuclear complexes

Co-reporter:Hui Wang, Xu-Qing Guo, Rui Zhong, Yue-Jian Lin, Peng-Cheng Zhang, Xiu-Feng Hou

Journal of Organometallic Chemistry 2009 694(20) pp: 3362-3368

Publication Date(Web):

DOI:10.1016/j.jorganchem.2009.05.034

Synthesis and Structure of Half-Sandwich Pyridine-2-thiolato Cobalt(III) and Rhodium(III) Complexes and Their Reactivity toward Monodentate or Bidentate 1,2-Dicarba-closo-dodecaborane Thiolate Ligands

Co-reporter:Shu Liu, Hui Wang, Peng-Cheng Zhang, Lin-Hong Weng and Xiu-Feng Hou

Organometallics 2008 Volume 27(Issue 4) pp:713-717

Publication Date(Web):February 1, 2008

DOI:10.1021/om701120w

The half-sandwich cobalt(III) and rhodium(III) complexes with pyridine-2-thiolato ligands Cp*Co(PyS)I (3) and Cp*Rh(PyS)Cl (4) [Cp* = pentamethylcyclopentadienyl, PyS = pyridine-2-thiolate] were obtained by reactions of lithium pyridine-2-thiolate (PySLi) with Cp*Co(CO)I2 (1) and [Cp*RhCl2]2 (2), respectively, in high yield. Complexes 3 and 4 reacted with monodentate LiSC2(H)B10H10 to give Cp*Co(PyS)[SC2(H)B10H10] (5) and Cp*Rh(PyS)[SC2(H)B10H10] (6), respectively. Reactions of 3 and 4 with Li2S2C2B10H10 resulted in C−H activation of a methyl group of the Cp* of the cobalt complex to give [(C5Me4CH2SC5H4N)Co(S2C2B10H10)] (7). No such activation of a methyl group of the Cp* of the rhodium complex occurred, and Cp*Rh[Py(H)S](S2C2B10H10) (8) was the product.

Transformation of a Cp*-iridium carbene catalyst in water oxidation using Oxone as primary oxidant

Co-reporter:Hui Cao, Jing-Fan Zhang, Quan Zhou, Shuang Huang, Xi Hong, Xiu-Feng Hou

Molecular Catalysis (June 2017) Volume 434() pp:49-56

Publication Date(Web):1 June 2017

DOI:10.1016/j.mcat.2017.01.029

•Ir catalyzed water oxidation using Oxone as primary oxidant.•Precatalyst evolved into blue and purple solution.•The catalytic resting species were speculated.Fundamental understanding of the real catalytic species in water oxidation is a major knowledge gap that must be overcome in order to develop artificial water splitting systems and produce chemical fuels from solar energy. In an effort to analyze the transformation and catalytic resting state of [Cp*Ir(pmNHC)Cl]Cl [pmNHC = 1-(2-pyrimidyl)-3-n-butylimidazol-2-ylidene, Cp* = pentamethylcyclopentadienyl] in water oxidation using potassium peroxymonosulfate (Oxone) as primary oxidant, we found the precatalyst evolved into blue solution when a small amount of Oxone was added while further oxidation yield purple solution. These species have been proven to be homogeneous and they remain active in water oxidation. 1H NMR profiles and MALDI-MS data suggested a rapid oxidation of the Cp* ligand to acetone, formic and acetic acid. 1H NMR, TEM-EDX as well as MALDI-MS data indicated a continuous degradation of pyrimidyl, butyl and NHC groups. MALDI-MS, XANES and 17O NMR spectroscopy data of the blue species are most consistent with an iridium(III) compound with two waters, one dioxygen and pmNHC group. The catalytic resting purple species probably consists of an iridium(III) complex with three waters, one chloride and one bicarbonate ligand. Besides, the presence of a small amount of iridium aqua ion oligomers was observed in the purple species. The formation of polymers and nanoparticles is likely to be inhibited by the acid environment.Download full-size image

Novel Pb(II) ion-imprinted materials based on bis-pyrazolyl functionalized mesoporous silica for the selective removal of Pb(II) in water samples

Co-reporter:He-Zhen Cui, Yuan-Long Li, Shu Liu, Jing-Fan Zhang, Quan Zhou, Rui Zhong, Min-Li Yang, Xiu-Feng Hou

Microporous and Mesoporous Materials (15 March 2017) Volume 241() pp:

Publication Date(Web):15 March 2017

DOI:10.1016/j.micromeso.2016.12.036

•Three new Pb(II) ion-imprinted mesoporous silicas were prepared.•These bis-pyrazolyl functionalized SBA-15, MCM-41 and FDU-12 were used as Pb(II) adsorbents.•The adsorption performances of the three Pb(II) ion-imprinted adsorbents were investigated.•Adsorbent based on MCM-41 showed excellent adsorption capacity, selectivity and reusability.•Pb-IIMS-MCM-41 packed solid-phase extraction column for removal of Pb(II) was conducted.Three highly efficient adsorbents Pb-IIMS-SBA-15, Pb-IIMS-MCM-41 and Pb-IIMS-FDU-12 for Pb(II) were prepared by grafting the functional monomer 4-(di (1H-pyrazol-1-yl) methyl) phenol (DPP) on corresponding mesoporous silicas with Pb(II) as temple. All these three Pb(II) ion-imprinted mesoporous silica (Pb-IIMS) were characterized by Fourier transform-infrared spectroscopy (FT-IR), solid-state 29Si and 13C NMR spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), N2 adsorption–desorption analysis and small angel X-ray diffraction (XRD). The adsorption experiments revealed three Pb-IIMS all possessed considerable adsorption performance for Pb(II), their adsorption profiles obeyed pseudo-second-order kinetics and Langmuir isotherm model. Compared with their corresponding non-imprinted materials, three Pb-IIMS displayed satisfactory selectivity to Pb(II) over seven competing metal ions. Among them, Pb-IIMS-MCM-41 particularly owned outstanding adsorption performance and selectivity, the maximum adsorption capacity as high as 344.8 mg g−1, as well as excellent reusability through twelve adsorption-desorption cycles. Additionally, Pb-IIMS-MCM-41 was employed as packing material to construct a solid-phase extraction column for detection of Pb(II), which exhibited detection limit of 0.015 μg L−1, then method was successfully applied to the removal and determination of trace Pb(II) in practical water samples.

Pd(OAc)2 catalyzed direct arylation of electron-deficient arenes without ligands or with monoprotected amino acid assistance

Co-reporter:Ya-Nong Wang, Xu-Qing Guo, Xiao-Han Zhu, Rui Zhong, Li-Hua Cai and Xiu-Feng Hou

Chemical Communications 2012 - vol. 48(Issue 84) pp:NaN10439-10439

Publication Date(Web):2012/09/06

DOI:10.1039/C2CC34949C

Palladium, iridium and ruthenium complexes with acyclic imino-N-heterocyclic carbenes and their application in aqua-phase Suzuki–Miyaura cross-coupling reaction and transfer hydrogenation

Co-reporter:Xu-Qing Guo, Ya-Nong Wang, Dong Wang, Li-Hua Cai, Zhen-Xia Chen and Xiu-Feng Hou

Dalton Transactions 2012 - vol. 41(Issue 48) pp:NaN14567-14567

Publication Date(Web):2012/11/07

DOI:10.1039/C2DT31989F