Inorganic Chemistry, Vol.44, No.18, 6277-6283, 2005
Molecular dynamics of a vanadate-dipeptide complex in aqueous solution
Static geometry optimizations and Car-Parrinello molecular dynamics simulations with the BP86 density functional, as well as NMR chemical shift calculations at the GIAO-B3LYP level, have been used to assess structure, speciation, and dynamics of aqueous solutions of the vanadate-glycylglycine complex. According to the simulations, this complex should be formulated as five-coordinate, anionic [VO2(GlyGly')](-)(GlyGly' = H2N-CH2-C(O)-N-CH2-CO2). The neutral conjugate acid is unstable in water, where it is deprotonated within a few picoseconds. Six-coordinate structural alternatives, [VO(OH)(2)(GlyGly')](-), are disfavored energetically and/or entropically. The hydration shell around [VO2(GlyGly')](-) in water is characterized in terms of suitable pair correlation functions.