Structure, solvation, and bonding in pentacyano(L)ferrate(II) ions (L=aliphatic amine): a density functional study

MARIANO C. GONZÁLEZ LEBRERO; ADRIAN G. TURJANSKI; JOSÉ A. OLAVE; DARÍO A. ESTRIN

JOURNAL OF MOLECULAR MODELING - (Online)

Año: 2001 p. 201 - 206

0948-5023

Quantum chemical calculations using densityfunctional theory have been carried out to investigate theinfluence of aqueous solvation on the structure andbonding in [Fe(CN)5L]3– with L an aliphatic amine (am-monia, methylamine, hydrazine, and ethylenediamine).Gas phase equilibrium geometries were fully optimizedat the generalized gradient approximation (GGA) level.Solvent effects were modeled within the DFT methodol-ogy by using a discrete electrostatic representation of thewater molecules in the first solvation shell. For the hy-drazine and ethylenediamine complexes in vacuum wefound two internal hydrogen bonds between the terminalamino group hydrogens and two equatorial cyanide li-gands. However, considering the first solvation shell, anopen structure in which the terminal amino group issolvated by water molecules becomes more stable in theethylenediamine case. Metal–L dissociation energieswere computed in vacuum, taking the first solvationshell into account. The results obtained were comparedwith experimental kinetic data in aqueous solution in or-der to assess the role of solvation in the reactivity ofthese complexes.