Tetrahydrogendecavanadate(V) and its binding to glycylglycine

An adduct between the tetrahydrogen form of decavanadate H4V10O282- and glycylglycine, with the stoichiometry Rb2H4V10O28 . 2Gly-Gly . 2H(2)O, has been isolated and fully characterized. The crystal structure has been determined hv X-ray diffraction data. The four hydrogen atoms of the polyvanadate framework could not be located directly, but structural features suggest strongly that they are associated with two triply bridging and two doubly bridging oxygens atoms. Two dipeptide molecules interact with the decavanadate polyanion via a hydrogen bond between O atoms of the carboxylic groups and a couple of doubly bridging surface atoms, which act as accepters, In addition, there are hydrogen bonding contacts in which the nitrogen atoms and the carbonyl oxygen of the dipeptide molecules take part. IR spectroscopy proved useful in establishing the protonation state of Gly-Gly. (C) 1999 Published by Elsevier Science S.A. All rights reserved.