Characterization of structure and dynamics of an aqueous scandium(III) ion by an extended ab initio QM/MM molecular dynamics simulation.
Hydration structure and dynamics of an aqueous Sc(III) solution were characterized by means of an extended ab initio quantum mechanical/molecular dynamical (QM/MM) molecular dynamics simulation at Hartree-Fock level. A monocapped trigonal prismatic structure composed of seven water molecules surrounding scandium(III) ion was proposed by the QM/MM simulation including the quantum mechanical effects for the first and second hydration shells. The mean Sc(III)-O bond length of 2.14 Å was identified for six prism water molecules with one capping water located at around 2.26 Å, reproducing well the X-ray diffraction data. The Sc(III)-O stretching frequency of 432 cm(-1) corresponding to a force constant of 130 N m(-1), evaluated from the enlarged QM/MM simulation, is in good agreement with the experimentally determined value of 430 cm(-1) (128 N m(-1)). Various water exchange processes in the second hydration shell of the hydrated Sc(III) ion predict a mean ligand residence time of 7.3 ps.
Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Viwat
V
Vchirawongkwin
Chinapong
C
Kritayakornupong
Anan
A
Tongraar
Bernd M
BM
Rode
D007477:Ions / Q000737:chemistry; D008024:Ligands; D056004:Molecular Dynamics Simulation; D011789:Quantum Theory; D012538:Scandium / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D007477:Ions; D008024:Ligands; D014867:Water; D012538:Scandium