Xian-Man Zhang

Shaoxing University, Shao-hsing, Zhejiang Sheng, China

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Publications (17)43.18 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Palladium (Pd)-catalyzed desulfitative cross-coupling reactions of sodium arylsulfinates with a wide variety of arylboronic acids were achieved in good to excellent yields under simple aerobic conditions. These catalytic reactions could be accelerated by addition of a catalytic amount of Cu(II) salts as co-catalyst. Moreover, these reactions were tolerant to all of the tested functional groups, making them attractive alternatives to the traditional cross-coupling reactions.
    RSC Advances 11/2014; 4(101). · 3.71 Impact Factor
  • Linjun Shao, Chenze Qi, Xian-man Zhang
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    ABSTRACT: Chlorinated polyvinylchloride (CPVC) nanofiber mats were prepared by electrospinning technique, and then treated with amines of different chemical structures, followed by immobilization of palladium catalysts (CPVC-NH2-Pd), which have been demonstrated as efficient, stable and easily recyclable heterogeneous catalysts. Their catalytic activities could be correlated with the binding energies of the palladium species with the amine chelating ligands.
    RSC Advances 10/2014; · 3.71 Impact Factor
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    ABSTRACT: In this study, chitosan directly cross-linked by PdII cation membranes (Pd-cr-CSM) with good mechanical strength and thermal stabilities have been prepared. Although the prepared Pd-cr-CSM has neither open porous structure nor high specific surface areas, it has similar good catalytic activity and much higher stability as compared with typical prepared chitosan-stabilized palladium heterogeneous catalysts for Heck reactions. It is highly active for the Heck reactions of aryl iodides and bromides with a strong electron-withdrawing group at a palladium catalyst loading of 0.15 mol %. It can be recycled 12 times in dimethyl sulfoxide (DMSO) solution or 7 times in aqueous solution. The high activity and extreme stability of the Pd-cr-CSM catalyst are mainly attributed to the well-entrapped palladium nanoparticles inside the chitosan matrix, which might catalyze the coupling reactions in the free volume holes (open spaces) of the swollen cross-linked chitosan gel networks.
    Industrial & Engineering Chemistry Research. 06/2014; 53(24):10041–10050.
  • Kai Cheng, Sai Hu, Baoli Zhao, Xian-Man Zhang, Chenze Qi
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    ABSTRACT: Palladium-catalyzed Hiyama-type cross-coupling reactions of various arenesulfinates with organosilanes were achieved in good to excellent yields under aerobic conditions at 70 °C. Fluoride is essential, and tetrabutylammonium fluoride (TBAF) was shown to be the most efficient additive for these cross-coupling reactions. These cross-coupling reactions of the arenesulfinates provide high yields and show wide functional group tolerance, making them attractive alternative transformations to traditional cross-coupling approaches for carbon-carbon bond construction.
    The Journal of Organic Chemistry 05/2013; · 4.56 Impact Factor
  • Minfeng Zeng, Chenze Qi, Xian-Man Zhang
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    ABSTRACT: Significant enhancement of the catalytic stability and activity was obtained for the heterogeneous palladium catalyst supported on the shell powders-reinforced chitosan microspheres. For example, over 90% cross-coupling yields were achieved using as low as 0.05mol% palladium catalyst loading for the Heck-type reaction of iodobenzene with n-butyl acrylate. Such significant enhancement of the catalytic stability and activity can be attributed to the intermolecular interactions of the surface polar molecules of the incorporated shell powders with the surrounding chitosan molecules as well as the deposited palladium species.
    International journal of biological macromolecules 01/2013; · 2.37 Impact Factor
  • Minfeng Zeng, Xudong Sun, Chenze Qi, Xian-Man Zhang
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    ABSTRACT: A novel and environmentally friendly heterogeneous catalyst has been prepared through the wet impregnation of copper(I) species onto the highly porous chitosan microspheres (CuI/PCMS). This novel CuI/PCMS heterogeneous catalyst with no additional ligands is much better than CuI homogeneous catalysts when applied in Heck reactions. Moreover, the reaction conditions are much milder than those for the similar copper catalysts mediated cross-coupling reactions reported in the literature. PCMS has been demonstrated not only the excellent solid support, but also have many unique functional groups to chelate the copper (I) species to enhance its catalytic activity.
    Kinetics and Catalysis 01/2013; 54(6). · 0.54 Impact Factor
  • Minfeng Zeng, Xin Zhang, Chenze Qi, Xian-Man Zhang
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    ABSTRACT: In this study, polyethylene glycol (PEG) with different molecular weight, polyvinyl pyrrolidone (PVP), and polyvinyl alcohol (PVA), are chosen as porogens for preparing chitosan base porous microsphere supported palladium catalyst for coupling reactions. The pore structure of the microspheres was controlled by the compatibility of chitosan and counterpart polymers. The prepared porous chitosan microspheres supported palladium heterogeneous catalysts have been evaluated using the well-established Ullmann reductive homocoupling and the Heck cross-coupling reactions. The activities, stabilities and recyclability of the porous chitosan microspheres supported palladium catalysts are not only highly dependent upon the surface areas of the solid supports, but also upon the chemical properties of the water-soluble polymers. The degradation of the prepared heterogeneous palladium catalysts is mainly caused by a combination of the palladium leaching and the morphological transformation of the palladium species from the amorphous into the crystals.
    International journal of biological macromolecules 07/2012; 51(5):730-7. · 2.37 Impact Factor
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    ABSTRACT: Porous chitosan microspheres (PCMS) were prepared from crosslinking chitosan/polyethylene glycol (PEG) interpenetrating microspheres through selective dissolution of the water-soluble PEG component for the immobilization of palladium catalyst. The resultant Pd/PCMS supported palladium has been demonstrated as a highly active and easily recyclable heterogeneous catalyst for the Ullmann-type reductive homocoupling of aromatic halides and the Heck cross-coupling of aromatic halides with acrylates. Most interestingly, the prepared Pd/PCMS heterogeneous palladium catalyst can also be employed in the environmentally-benign aqueous solution due to the highly hydrophilic hydroxyl and amino functional groups of chitosan. The large size of the microsphere structure can greatly facilitate separation and recycling of the expensive and toxic palladium catalysts from the reaction mixture and the recovered Pd/PCMS catalyst can preserve the catalytic activity and selectivity for the Heck reaction without any observable degradation over ten recycling times. The high activity and stability of the Pd/PCMS catalyst have been attributed to a combination of the high specific surface area of the porous structure as well as the strong chelation of palladium species with the abundant chitosan surface hydroxyl, amino and carbonyl functional groups.
    Journal of Organometallic Chemistry 05/2012; 704:29–37. · 2.00 Impact Factor
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    ABSTRACT: Palladium acetate [Pd(OAc)(2)]-catalyzed Hiyama cross-coupling of arenediazonium salts with organosilanes was found to generate biaryl products in high yields in alcoholic solutions. The simple and efficient protocol does not require any bases, ligands, or air/moisture. The transformation can tolerate either electron-donating or electron-withdrawing functional groups. Theoretical studies show that the transmetalation is the rate-limiting step for the cross-coupling reaction and both acetate and tetrafluoroborate anions may be involved in the direct reaction with the silicon atom.
    The Journal of Organic Chemistry 11/2011; 76(22):9261-8. · 4.56 Impact Factor
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    ABSTRACT: An efficient and recyclable ligand-free heterogeneous catalyst has been prepared by the immobilization of palladium onto ground pearl shell powders (Pd/shell powders, Pd/SP). The catalytic activity and recyclability of the prepared Pd/SP along with the charcoal and calcium carbonate supported palladium (Pd/C and Pd/CaCO3) catalysts have been evaluated using the reductive homocoupling of aromatic halides. Pd/SP not only has higher catalytic activity, but also exhibits much stronger stability than Pd/C and Pd/CaCO3. The remarkable Pd/SP stability has been attributed to the chelation of palladium species with the surface chitin and protein molecules of the supported pearl shell powders. The X-ray photoelectron spectroscopy (XPS) studies show that the reductive Pd0 species can be regenerated in situ from the oxidative Pd2+ species for the Pd/SP catalyzed reductive homocoupling of aromatic halides in ethanol/DMSO solution, suggesting that the heterogeneous and homogeneous palladium catalysis proceeds through a similar Pd0/Pd2+ cycle catalytic mechanism.
    Green Chemistry 02/2011; 13(2):350-356. · 6.83 Impact Factor
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    ABSTRACT: Palladium-catalyzed reductive homocoupling of aromatic halides can be performed in alcohol solutions without any auxiliary reducing reagents. Pd(dppf)Cl(2) [dppf = 1,1'-bis(diphenylphosphino)ferrocene] has been shown as the most effective catalyst among the palladium catalysts screened for the model reductive homocoupling of iodobenzene in alcoholic solutions. The reduction of iodobenzene is stoichiometrically coupled with the oxidation of solvent alcohol (3-pentanol). The X-ray photoelectron spectroscopic (XPS) studies clearly indicate that the oxidation of solvent alcohol molecules is involved with the in situ regeneration of the reductive Pd(0)(dppf) active species, indicating that the solvent alcohol also reacts as a reducing reagent for the reductive homocoupling of aromatic halides. Elimination of the external reducing reagents will simplify the product separation and purification. Base is essential for the success of the Pd(dppf)Cl(2)-catalyzed redox reaction as 2 molar equiv of base is needed to neutralize the acid byproduct formed. Biaryls are the predominant products for the Pd(dppf)Cl(2)-catalyzed reductions of the unsubstituted aromatic halides in 3-pentanol solution, whereas the dehalogenation products are predominant for the Pd(dppf)Cl(2)-catalyzed reductions of the substituted aromatic halides. The reaction mechanisms have been discussed for the palladium-mediated concomitant reduction of aromatic halides and oxidation of alcohols without any auxiliary reductants and oxidants.
    The Journal of Organic Chemistry 03/2010; 75(8):2556-63. · 4.56 Impact Factor
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    ABSTRACT: For the first time, ethanol is used as reducing agent in the presence of a base for the homocoupling reaction of aryl/pyridyl bromides or iodides to afford symmetric biaryls.
    Applied Organometallic Chemistry 02/2010; 24(5):421 - 425. · 2.01 Impact Factor
  • ChemInform 12/2009; 40(52).
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    ABSTRACT: The homolytic bond dissociation enthalpies (BDEs) of the acidic C-H bonds in a series of phosphonates and related phosphorus-containing compounds have been determined by a combination (eq 3) of their equilibrium acidities (pK(HA)'s) and the oxidation potentials [E(ox)(A(-))'s] of their conjugate anions, which were measured in DMSO solution. The equilibrium acidity increases by 15.5, 14.9, and 10.9 pK units for the introduction of an alpha-P(O)(OEt)(2) group into toluene, acetonitrile, and ethyl acetate, respectively. Comparison with the published equilibrium acidity increases by 25.6, 24.4, and 21.0 pK units for the introduction of an alpha-(+)PPh(3) group into the same series of substrates indicates that the phosphoryl carbanions (Horner-Wadsworth-Emmons reagents) are about 10 pK units more reactive than the corresponding triphenylphosphonium ylides (Wittig reagents). However, both alpha-P(O)(OEt)(2) and alpha-(+)PPh(3) groups have negligible effects on the adjacent C-H BDEs, indicating that there is no resonance delocalization into the 3d vacant orbitals of phosphorus and that their acidifying effects are exclusively associated with the field/inductive (electrostatic) and polarizability effects. The acidifying effect of an alpha-CO(2)Et group is shown to be ca. 3.5 pK units stronger than that of an alpha-P(O)(OEt)(2) group in the same substrates, suggesting that the larger acidifying effect of the alpha-CO(2)Et group is predominantly associated with the resonance delocalization rather than with the field/inductive (electrostatic) and polarizability effects.
    The Journal of Organic Chemistry 10/2009; 74(21):8078-85. · 4.56 Impact Factor
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    ABSTRACT: A series of epoxy resin (EP) composites were prepared using ground pearl shell powders, which had been calcined at various temperatures. The EP composite containing ∼ 3% weight content of the calcined pearl shell powder had the highest impact strength and the presence of silane agent was found to be essential for the composite formulation. The impact strengths of the resultant EP composites were highly influenced by the specific surface area, surface morphological structure, and chemical composition of the calcined pearl shell powder. The highest mechanical improvement was obtained for the EP composite prepared with the pearl shell powder calcined at 700°C for 3 h. The layered biopolymeric materials were completely degraded for the pearl shell powder calcined at 700°C, resulting in “sponge-like” or “net-like” porous calcium carbonate powder. However, the degradation of the layered biopolymeric materials was not complete for the calcinations at lower temperatures (<600°C), while calcium carbonate decomposed to form calcium oxide at higher temperatures (>800°C). The mechanical improvements of the processed EP composites have been discussed along with the chemical compositions and surface microstructures of the incorporated pearl shell powders. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
    Journal of Applied Polymer Science 07/2009; 114(5):3168 - 3176. · 1.40 Impact Factor
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    ABSTRACT: Biaryls were obtained in good to excellent yields from the palladium catalyzed reductive homocoupling reactions of various aryl iodides and bromides in dimethyl sulfoxide (DMSO) solution without the need for any additional reducing reagents. Pd(dppf)Cl2 is the most effective among the screened palladium catalysts for the homocoupling reactions. Fluorides, carbonates, acetates and hydroxides can be used as bases at promoting the palladium catalyzed reductive homocoupling of aryl halides in DMSO solution. X-ray photoelectron spectroscopic (XPS) analysis shows that the oxidative Pd2+(dppf) species can be reduced into the Pd0(dppf) active species by solvent DMSO molecules to furnish the catalytic cycle, indicating that DMSO plays a dual role as both solvent and reducing reagent. A plausible reaction mechanism has been discussed. Elimination of additional reducing reagents will not only reduce the reaction operation cost, but will also simplify the product separation and purification.
    Journal of Organometallic Chemistry - J ORGANOMET CHEM. 01/2009; 694(18):2912-2916.
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    ABSTRACT: Nanoporous poly(vinyl alcohol) (PVA) nanofiber mats prepared by means of electrospinning have been used for the immobilization of palladium catalyst. Thermal treatment of the palladium-loaded PVA nanofiber mats results in the cross-linking of the matrix PVA molecules as well as the reduction of the divalent palladium (Pd2+) into zerovalent palladium (Pd0) species. The palladium oxidation states were examined by X-ray photoelectron spectroscopic (XPS) analysis. The PVA nanofiber morphology was characterized by scanning electron microscopy (SEM). The catalytic activity and recyclability of the prepared heterogeneous palladium catalysts have been evaluated for the Ullmann, Heck–Mizoroki and Sonogashira coupling reactions of aromatic halides. The large structure of the Pd/PVA nanofiber mats can greatly facilitate its separation and recycling, and the high catalytic activity and stability of the prepared Pd/PVA nanofiber mats have been attributed to the chelation of palladium species with the abundant hydroxyl functional groups on the PVA matrix surface area.
    Applied Catalysis A: General. s 413–414:267–272.