Konstantina E. Chrysomallidou, S. Perlepes, A. Terzis
Jul 15, 2011
Citations
0
Influential Citations
6
Citations
Journal
Inorganica Chimica Acta
Abstract
Abstract Reactions of Ca(NO 3 ) 2 ·4H 2 O and diethylmalonic acid (Et 2 malH 2 , its anions represent functional side-chain analogs of γ-carboxyglutamic acid residues which are implicated as essential Ca 2+ -binding ligands in a variety of proteins) in aqueous media have afforded compounds [Ca(Et 2 malH) 2 (H 2 O) 3 ] n ( 1 ) and [Ca(Et 2 mal)(H 2 O)] n ( 2 ) at pH 4 and 8, respectively. The structure of 1 was determined by single-crystal, X-ray crystallography, which revealed an 1D coordination polymer. The diethylmalonate ligands exist in their monoanionic form and present two different coordination modes. The Ca II ion is 7-coordinate with a pentagonal bipyramidal geometry. IR data are discussed in terms of the known ( 1 ) and proposed ( 2 ) structures of the complexes. The role of the carboxylate binding modes in determining the affinity of Ca 2+ for the various metal binding sites in proteins containing the γ-carboxyglutamate residue is discussed in the light of our and previous results.