Hydrolysis of β-Lactam Antibiotics Catalyzed by Dinuclear Zinc(II) Complexes: Functional Mimics of Metallo-β-lactamases
摘要:
Three stable dinuclear zinc(II) complexes, [Zn2L1(mu-NO3)(NO3)(2)] and [Zn2L1(mu-OMe)(NO3)(2)], where L-1 is 2,6-bis {{N-(2-dimethylaminoethyl)-N-methyl]aminomethyl}-4-methylphenolate, and [Zn2L2(NO3)(3)], where L-2 is 2-{[N-(2-dimethylaminoethyl)-N-methyl]aminomethyl}-4-bromo-6-{[N'-2-(2'-pyridyl)ethyl]aminomethyl}phenolate, were synthesized and characterized in the solid stare and in aqueous solution. These complexes catalyze the hydrolysis of penicillin G and nitrocefin, serving as functional synthetic analogues of the metallo-beta-lactamases, bacterial enzymes responsible for antibiotic resistance. The mechanism of the hydrolysis was studied in detail for the catalyst precursor [Zn2L1(mu-NO3)(NO3)(2)], which converts into [Zn2L1(mu-OH)(NO3), (sol)(2-n)]((2-n)+) in the presence of water. The complex [Zn2L1(mu-OH)(No-3)(2)] (n = 2) was characterized in the solid state. Initial coordination of the substrate carboxylate group is followed by the rate-limiting nucleophilic attack of the bridging hydroxide at the beta-lactam carbonyl group in aqueous solution. The product is formed upon fast protonation of the intermediate. Mononuclear complexes Zn(cyclen)(NO3)(2) and Zn(bpta)(NO3)(2) are as reactive in the beta-lactam hydrolysis as the dinuclear complexes. Consequently, the second zinc ion is not required for catalytic activity.
Comparison of structurally analogous Zn<sub>2</sub>, Co<sub>2</sub>, and Mg<sub>2</sub>catalysts for the polymerization of cyclic esters
作者:Laurie E. Breyfogle、Charlotte K. Williams、Victor G. Young, Jr.、Marc A. Hillmyer、William B. Tolman
DOI:10.1039/b507014g
日期:——
Three dimetallic monoethoxide complexes supported by a binucleating phenoxide ligand, LM2Cl2OEt (M = Zn, Co, or Mg), were prepared and shown by X-ray crystallography to be structurally analogous. Comparative studies of their cyclic ester polymerization reactivity revealed different trends for reactions with ε-caprolactone and lactide, however, implicating complicated effects of metal ion variation in these polymerizations.
通过双核化苯氧基配体支撑的三金属单乙氧基配合物 LM2Cl2OEt(M = Zn、Co 或 Mg)被制备出来,并通过 X 射线晶体学证明它们在结构上相似。它们对环酯聚合反应性的比较研究表明,在与ε-己内酯和乳酸酯的反应中呈现出不同的趋势,然而,这暗示了在这些聚合中金属离子变化所带来的复杂影响。
Metalloenzyme inspired dizinc catalyst for the polymerization of lactide
作者:Charlotte K. Williams、Neil R. Brooks、Marc A. Hillmyer、William B. Tolman
DOI:10.1039/b206437e
日期:2002.9.11
A new dizinc–monoalkoxide complex supported by a dinucleating ligand was structurally characterized and shown to be a highly active catalyst for the controlled polymerization of lactide.
一种由双核配体负载的新型二锌-单醇盐络合物进行了结构表征,并表明它是丙交酯受控聚合的高活性催化剂。
Hydrolysis of β-Lactam Antibiotics Catalyzed by Dinuclear Zinc(II) Complexes: Functional Mimics of Metallo-β-lactamases
作者:Natalia V. Kaminskaia、Bernhard Spingler、Stephen J. Lippard
DOI:10.1021/ja993704l
日期:2000.7.1
Three stable dinuclear zinc(II) complexes, [Zn2L1(mu-NO3)(NO3)(2)] and [Zn2L1(mu-OMe)(NO3)(2)], where L-1 is 2,6-bis N-(2-dimethylaminoethyl)-N-methyl]aminomethyl}-4-methylphenolate, and [Zn2L2(NO3)(3)], where L-2 is 2-[N-(2-dimethylaminoethyl)-N-methyl]aminomethyl}-4-bromo-6-[N'-2-(2'-pyridyl)ethyl]aminomethyl}phenolate, were synthesized and characterized in the solid stare and in aqueous solution. These complexes catalyze the hydrolysis of penicillin G and nitrocefin, serving as functional synthetic analogues of the metallo-beta-lactamases, bacterial enzymes responsible for antibiotic resistance. The mechanism of the hydrolysis was studied in detail for the catalyst precursor [Zn2L1(mu-NO3)(NO3)(2)], which converts into [Zn2L1(mu-OH)(NO3), (sol)(2-n)]((2-n)+) in the presence of water. The complex [Zn2L1(mu-OH)(No-3)(2)] (n = 2) was characterized in the solid state. Initial coordination of the substrate carboxylate group is followed by the rate-limiting nucleophilic attack of the bridging hydroxide at the beta-lactam carbonyl group in aqueous solution. The product is formed upon fast protonation of the intermediate. Mononuclear complexes Zn(cyclen)(NO3)(2) and Zn(bpta)(NO3)(2) are as reactive in the beta-lactam hydrolysis as the dinuclear complexes. Consequently, the second zinc ion is not required for catalytic activity.
Dinuclear Zinc Complexes Using Pentadentate Phenolate Ligands
作者:Paul D. Knight、Andrew J. P. White、Charlotte K. Williams
DOI:10.1021/ic8014173
日期:2008.12.15
The synthesis and characterization of 15 dinuclear zinc complexes are reported, including the X-ray crystal structures of 5 complexes. The ligand motif utilizing p-cresol as a bridging unit between the two zinc centers and a set of three related ligands has been synthesized; 2,6-bis(R)-p-cresol (where R is CH(2)NMe(CH(2))(2)NMe(2) = L(1), CH=N(CH(2))(2)NMe(2) = L(2), and CH(2)NH(CH(2))(2)NMe(2) = L(3))