Structural characterization of copper complexes with chiral 1,2,4-triazine-oxazoline ligands

Heterocyclic communications

article

Ewa Wolińska¹  Zbigniew Karczmarzyk¹  Waldemar Wysocki¹ 

[1] Department of Chemistry, Siedlce University

关键词: asymmetric catalysis;    chiral 1;    2;    4-triazine-oxazoline ligands;    enantioselective nitroaldol reaction;    X-ray diffraction analysis;   

DOI  :  10.1515/hc-2016-0103

学科分类：内科医学

来源: De Gruyter

【 摘 要 】

The crystal structure determination of oxazoline-1,2,4-triazine ligand 1f and pyridine-oxazoline ligand 2g was used to analyze their conformational preferences when forming complexes with metals. Proton nuclear magnetic resonance ( 1 H NMR), electrospray ionization mass spectrometry and UV-vis spectroscopy as well as theoretical calculation using molecular mechanics (MM) were adopted to study the composition and geometry of oxazoline-1,2,4-triazine ligands 1 complexes with copper(II) acetate monohydrate. The study revealed that during the complexation, (i) Cu(II) ion is reduced to Cu(I) upon the ligand-to-metal charge transfer transition and (ii) the ligands form with copper(I) 2:1 (L:Cu) complexes of tetrahedral geometry. On the basis of the findings, the catalytic cycle and the active transition state for the enantioselective nitroaldol reaction (the Henry reaction) catalyzed by 1 –Cu are proposed.

【 授权许可】

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