Wen-Chou Hung

National Chung Hsing University, Taichung, Taiwan, Taiwan

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Publications (11)31.15 Total impact

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    ABSTRACT: A series of lithium and sodium complexes with OOO-tridentate bis(phenolate) ligands have been synthesized and fully characterized. The reaction of 2,2'-dihydroxy-3,3',5,5'-tetrakis[(1-methyl-1-phenyl)ethyl]dibenzyl ether (L(1)-H(2)) with different ratios of (n)BuLi in toluene or tetrahydrofuran (THF) gave [Li(2)(L(1)-H)(2)] (1), [Li(4)L(1)(2)] (2), and [Li(2)L(1)(THF)(3)] (3), respectively. Similarly, [Na(L(1)-H)(THF)] (4), [Na(2)(L(1)-H)](2) (5), and [Na(4)L(1)(2)] (6) were prepared by the reaction of L(1)-H(2) and NaN[Si(CH(3))(3)](2) or sodium metal. In addition, the reaction of 2,2'-dihydroxy-3,3',5,5'-tetra-tert-butyldibenzyl ether (L(2)-H(2)) with (n)BuLi in toluene or THF yields Li(2)(L(2)-H)(2)] (7) and [Li(2)(L(2)-H)(2)(THF)(2)] (8), respectively. Further treatment of 7 with 2 mol equiv of benzyl alcohol provides [Li(2)(L(2)-H)(2)(BnOH)(2)] (9). Complexes 1-4 and 6-9 have been structurally characterized by single-crystal X-ray analysis. The dinuclear nature of complexes 1 and 3 was confirmed from their molecular structure. Complexes 2 and 6 illustrate tetranuclear species; however, complex 4 shows a mononuclear feature. A p-π interaction exists from the phenyl ring of the 2-(methyl-1-phenylethyl) groups to the central metal in complexes 2, 4, and 6, which could effectively stabilize the metal center. Among them, complexes 1, 2, and 5-9 displayed efficient catalytic behavior for the ring-opening polymerization of L-lactide in the presence of benzyl alcohol. Experimental results indicate that among these alkali-metal complexes, the sodium compound 6 displays a rapid catalytic polymerization of L-lactide in "living" fashion, yielding poly(L-lactide) with a controlled molecular weight and narrow polydispersity indices for a wide range of monomer-to-initiator ratios.
    Inorganic Chemistry 10/2010; 49(20):9416-25. · 4.59 Impact Factor
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    ABSTRACT: Multiple drug resistance (MDR) seriously reduces the efficacy of many chemotherapeutic agents for cancer. P-Glycoprotein, an efflux pump overexpressed on the cell surface, plays an important role in drug resistance, but several surfactants, such as vitamin E TPGS, can inhibit P-glycoprotein. In this study, a polylactide-surfactant block copolymer poly(l-lactide)-vitamin E TPGS (PLA-TPGS) was synthesized using bidentate sulfonamide zinc ethyl complex as an efficient catalyst, and its self-assembled nanoparticles were used as carriers of doxorubicin. We first found that the activity of P-glycoprotein in drug-resistant breast cancer MCF-7/ADR cells was decreased after incubation with PLA-TPGS nanoparticles. In addition, the nuclear accumulation and cytotoxicity of doxorubicin were significantly increased by encapsulation into the nanoparticles. The enhanced efficacy of the doxorubicin-loaded PLA-TPGS nanoparticles may result from the combination of inhibition of efflux and increased entry of doxorubicin into the nucleus in drug-resistant MCF-7/ADR cells. Therefore, this innovative delivery system has potential to act as a nanomedicine for therapy of both drug-sensitive and drug-resistant cancer.
    Biomacromolecules 10/2010; 11(10):2576-82. · 5.37 Impact Factor
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    ABSTRACT: A series of magnesium complexes have been prepared and characterized, in which [(EDBP-Me)Mg(mu-OBn)](2) (4) has shown high activity toward the ring-opening polymerization (ROP) of epsilon-caprolactone and L-lactide. 2,2'-Ethylidene-bis(4,6-di-tert-butylphenol)-monomethyl ether ([EDBP-(Me)H]) is prepared by the reaction of 2,2'-ethylidene-bis(4,6-di-tert-butylphenol) (EDBP-H(2)) with dimethyl sulfate. The reaction of [EDBP-(Me)H] with (n)Bu(2)Mg yields [(EDBP-Me)Mg(n)Bu](2), which further reacts with benzyl alcohol and N,N-dimethylethylenediamine giving complexes [(EDBP-Me)Mg(mu-OBn)](2) (4) and {[EDBP(Me)]Mg(mu-Me(2)NCH(2)CH(2)NH)}(2) (5), respectively. Experimental results indicate that the activity of complex 4 toward cyclic esters is higher than that of [(mu-EDBP)Mg](2)/(BnOH).
    Dalton Transactions 11/2009; · 4.10 Impact Factor
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    ABSTRACT: Four metal benzylalkoxides, [L2M2(μ-OBn)2] (M = Mg or Zn), based on NNO-tridentate ketiminate ligands are synthesized and characterized. X-ray crystal structural studies of [(L1)2Mg2(μ-OBn)2] (1a) and [(L1)2Zn2(μ-OBn)2] (1b) (L1-H = (Z)-4-((2-(dimethylamino)ethylamino)(phenyl)methylene)-3-methyl-1-phenyl-pyrazol-5-one) reveal that both complexes 1a and 1b are dinuclear species whereas the geometry around the metal center is penta-coordinated bridging through the benzylalkoxy oxygen atoms in the solid structure. The activities and stereoselectivities of these four complexes toward the ring-opening polymerization of L-lactide and rac-lactide are investigated. Polymerization of L-lactide initiated by these four metal benzyloxides proceeds rapidly with good molecular weight control and yields polymer with a very narrow molecular weight distribution. The kinetic studies for the polymerization of L-lactide with compound 1a show first order in both compound 1a and lactide concentrations with the polymerization rate constant, k, of 6.94 M/min. Besides, experimental results demonstrate that among these metal benzylalkoxides, complex 1a exhibits the highest stereoselectivity with a Pr up to 87% and complex 1b possesses the highest activity indicating that the terminal group of NNO-tridentate ketimine ligands exerts a significant influence on both the reactivity and stereoselectivity of these complexes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2318–2329, 2009
    Journal of Polymer Science Part A Polymer Chemistry 03/2009; 47(9):2318 - 2329. · 3.54 Impact Factor
  • Wen-Chou Hung, Chu-Chieh Lin
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    ABSTRACT: A series of magnesium benzyl alkoxides, [LMg(mu-OBn)](2) (1-8), supported by NNO-tridentate Schiff-base ligands are prepared by the reactions of Mg(OBn)(2) with one molar equivalent of related Schiff-base ligands (L(1)H-L(8)H) in toluene. The molecular structures of compounds 2, 3, 7, and 8 are characterized by X-ray structure determination. All of these compounds are crystallized as penta-coordinated dimers, and the central magnesium atoms are bridged by the oxygen atoms of benzyl alkoxides. The catalytic activities of complexes 1-8 toward the ring-opening polymerization of l-lactide are investigated. Experimental results indicate that the reactivity of [LMg(mu-OBn)](2) (1-8) is dramatically affected by the electronic effect of the substituents on the Schiff-base ligands, and 4 has the highest activity among them.
    Inorganic Chemistry 01/2009; 48(2):728-34. · 4.59 Impact Factor
  • Source
    Yueh-Hsuan Tsai, Wen-Chou Hung, Chu-Chieh Lin
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    ABSTRACT: The Cu atom of the title complex, [Cu(C(13)H(19)N(2)O(2))(C(10)H(8)N(2))]ClO(4), has a distorted square-pyramidal geometry with all three of the donor atoms from the N,N',O-tridentate Schiff base ligand in the equatorial positions and the bipyridine N atoms in an equatorial-axial binding mode. The Cu atom is 0.1801 (11) Å above the N(3)O mean basal plane.
    Acta Crystallographica Section E Structure Reports Online 01/2009; 65(Pt 5):m578. · 0.35 Impact Factor
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    ABSTRACT: A series of sterically bulky phenols (1a−f; EDBP-RTs-H = 2,4-di-tert-butyl-6-(1-(3,5-di-tert-butyl-2-hydroxyphenyl)ethyl)phenyl benzenesulfonate) were synthesized. Their related n-butylmagnesium complexes [(μ-EDBP-RTs)MgnBu]2 (2a−f) and magnesium alkoxides [(EDBP-RTs)Mg(μ-OBn)]2 (3a−f) were prepared and structurally characterized. In the presence of THF, coordination of [(EDBP-RTs)Mg(μ-OBn)]2 (3e) with THF gave the pentacoordinated magnesium complex [(EDBP-RTs)Mg(μ-OBn)(THF)]2 (4). Crystal structures of 2a−c,e, 3a−c,f, and 4 have been determined. Experimental results show that magnesium alkoxides (3a−f) are very reactive initiators toward ROP of l-lactide, with a quantitative yield of polymer (1000 equiv) in less than 4 min.
    Organometallics 08/2008; 27(19). · 4.15 Impact Factor
  • Wen-Chou Hung, Chu-Chieh Lin
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    ABSTRACT: The NiII atom in the title complex, [Ni(C17H17ClNO)2], is tetracoordinated by two N atoms and two O atoms from two bidentate salicylideneiminate ligands, forming a square-planar environment. The asymmetric unit consists of two half-molecules; in each molecule the Ni atom lies on a centre of symmetry.
    Acta Crystallographica Section E Structure Reports Online 12/2007; 63(12). · 0.35 Impact Factor
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    ABSTRACT: Three new metal alkoxides, [(MMPEP)Al(μ-OCH2C6H4CH2Cl)]2 (1), [(MMPEP–H)Li·(BnOH)]2 (2) and [(MMPEP–H)Li·(HOCH2C6H4CH2Cl)]2 (3) (MMPEP–H2: 2,2′-methylene-bis{4,6-di(1-methyl-1-phenylethyl)phenol}) have been synthesized and characterized. Complex 1 was prepared by the reaction of [(MMPEP)Al(CH3)(Et2O)] with p-(chloromethyl)benzyl alcohol. Followed by the reaction of MMPEP–H2 with nBuLi, BnOH or p-(chloromethyl)benzyl alcohol was added to give complexes 2 and 3, respectively. Complex 1 has shown excellent catalytic activity towards ring-opening polymerization (ROP) of ɛ-caprolactone. Both complexes 2 and 3 are active for ROP of l-lactide. Block copolymers of poly(ɛ-caprolactone)-b-polyacrylonitrile (PCL-b-PAN) and poly(l-lactide)-b-polyacrylonitrile can be synthesized by combining a technique of atom transfer radical polymerization (ATRP) and ROP using a double-headed initiator. Microphase-separated morphology of PCL-b-PAN has been observed by transmission electron microscopy, indicating the formation of self-assembled nanostructure.
    Polymer 07/2007; · 3.77 Impact Factor
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    Wen-Chou Hung, Shu-Ling Lai, Chu-Chieh Lin
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    ABSTRACT: The title complex, [Zn(2)(C(2)H(5))(2)(C(12)H(16)BrN(2)O)(2)], is dimeric, bridged through the O atoms of the phenolate anions. The molecule lies on a crystallographic twofold rotation axis. Each Zn atom is penta-coordinated by two N atoms and two bridging O atoms of the tridentate salicylideneiminate ligands and one C atom from an ethyl group, forming a distorted square-pyramidal environment.
    Acta Crystallographica Section E Structure Reports Online 01/2007; 64(Pt 1):m129-30. · 0.35 Impact Factor
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    ABSTRACT: Palladium-catalyzed Suzuki cross-coupling reactions employing Schiff-bases as ligands toward a series of substituted arylbromides and boronic acids were pursued. In the presence of a N,O-bidentate ligand, 2-[1-(2,4,6-trimethyl-phenylimino)-ethyl]-phenol 5, the catalytic reactions could be carried out efficiently at room temperature with a wide array of arylbromides, even with electronically deactivated arenes. A deprotonated 5, 5′, chelated palladium acetate complex, [5′Pd(II)(OAc)(solv)] 8, was proposed as a precursor of a genuine catalytically active species.
    ChemInform 01/2005; 61(40):9484-9489.