{"title":"Electron spin resonance studies of the solution structure of vanadyl amino acid complexes and mixed ligand complexes of oxalate","authors":"Craig R. Johnson, Rex E. Shepherd","doi":"10.1016/S0006-3061(00)80238-0","DOIUrl":null,"url":null,"abstract":"<div><p>Esr and electronic spectra of complexes of the general composition VO(AA)<sub>2</sub> and VO(ox)(AA) have been characterized; AA = gly, his, cys, pro, val, met, asp amino acids. Spectra of the formulation VO(ox)(LL) (with LL = imidazole plus monodentate oxalate, histamine plus monodentate oxalate, histidine, cysteine, 4-imidazolepropionic acid, mercaptopropionic acid, ethylenediamine and ethanolamine) have been used to deduce a self-consistent assignment of <em>A</em><sub>L</sub>, a ligand donor additivity constant contribution to the observed hyperfine splitting, <em>A</em><sub>iso</sub>. Values of <em>A</em><sub>L</sub> are sensitive to inductive effects in the ligand structure. The solution structures and likely coordination geometries of VO(his)<sub>2</sub>, VO(gly)<sub>2</sub>, and VO(cys)<sub>2</sub><sup>2−</sup> are discussed. The role of the imidazole moiety as a σ donor and sulfhydryl sulfur as a π acceptor is observed in VO(AA)<sub>2</sub> and VO(ox)(AA) complexes.</p></div>","PeriodicalId":9177,"journal":{"name":"Bioinorganic chemistry","volume":"8 2","pages":"Pages 115-132"},"PeriodicalIF":0.0000,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0006-3061(00)80238-0","citationCount":"19","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bioinorganic chemistry","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0006306100802380","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 19
Abstract
Esr and electronic spectra of complexes of the general composition VO(AA)2 and VO(ox)(AA) have been characterized; AA = gly, his, cys, pro, val, met, asp amino acids. Spectra of the formulation VO(ox)(LL) (with LL = imidazole plus monodentate oxalate, histamine plus monodentate oxalate, histidine, cysteine, 4-imidazolepropionic acid, mercaptopropionic acid, ethylenediamine and ethanolamine) have been used to deduce a self-consistent assignment of AL, a ligand donor additivity constant contribution to the observed hyperfine splitting, Aiso. Values of AL are sensitive to inductive effects in the ligand structure. The solution structures and likely coordination geometries of VO(his)2, VO(gly)2, and VO(cys)22− are discussed. The role of the imidazole moiety as a σ donor and sulfhydryl sulfur as a π acceptor is observed in VO(AA)2 and VO(ox)(AA) complexes.