Density-functional study of vanadate-glycylserine isomers

Optimized geometries (BP86/I) and computed 51V NMR chemical shifts (GIAO-B3LYP/I) are reported for selected [VO(OH)(OH2)(glyser')] isomers and deprotonated forms thereof (glyser' = H2N-CH2-CO-N-CH(CH2OH)-COO). The serine moiety can coordinate either with its carboxylic or with its alcoholic function, in accord with experiment. As found previously for the parent complex with glycylglycine, the water molecule is not bound to vanadium in the deprotonated, anionic forms. Qualitative agreement with experimental trends in delta(51V) is obtained for the anionic, but not for the neutral complexes.