Model complexes for the carboxylate–histidine–metal triad systems in metalloenzymes. Synthesis, crystal structures and spectroscopic properties of [M(Him)<sub>2</sub>(O<sub>2</sub>CMe)<sub>2</sub>](M = Zn<sup>II</sup>or Co<sup>II</sup>, Him = imidazole)
Two monomeric complexes [M(Him)(2)(O(2)CMe)(2)] (M = Zn-II 1 or Co-II 2, Him = imidazole) have been synthesized and structurally characterised by X-ray analysis. The complexes are isostructural. In each structure the metal atom is co-ordinated by a pair of acetate groups and a pair of Him ligands in a distorted-tetrahedral N2O2 environment with M-O 1.965(3)-1.991(2) and 1.972(4)-2.013(4) Angstrom, and M-N 1.996(2)-2.005(2) and 2.020(4)-2.030(5) Angstrom for 1 and 2, respectively The solid-state structures of both complexes involve intermolecular N-H ... O hydrogen bonds between the non-co-ordinated Him nitrogen atoms and the acetate oxygen atoms, with the acetate groups acting in both syn and anti modes, resulting in two types of carboxylate-imidazole-metal systems analogous to those found for metalloenzymes, The IR, Raman and C-13 NMR spectra of the complexes have been recorded and discussed in relation to the crystal structures.
Dalton communications. A model complex for the carboxylate–histidine–zinc system in zinc enzymes. Crystal structure of [Zn(Him)<sub>2</sub>(MeCO<sub>2</sub>)<sub>2</sub>](Him = imidazole)
作者:Xiao-Ming Chen、Zhi-Tao Xu、Xiao-Chun Huang
DOI:10.1039/dt9940002331
日期:——
The novel monomeric zinc(II) complex [Zn(Him)2(MeCO2)2] (Him = imidazole) has been prepared and structurally characterized; it is the first structural model for the carboxylate-histidine-zinc interactions frequently observed in zinc enzymes.