Study On The Structure And Property Of Transition Metal-benzenc Complexes

Transition metal^-benzene complexes have attracted great attention because they are very significant to the applications in renewable energy sources and the exploiture of novel materials, especially for novel magnetic materials and hydrogen storage materials. In this paper, we studied transition metal^-benzene complexes Mn（Bz）m （M=Ti, V, Cr, n≤₂, m≤₂, Bz=benzene） and obtained their ground state structures, the spin multiplicities, harmonic vibrational frequencies, electron affinities, mean bond dissociation energies and dipole moments with density functional B3LYP theory method. The basis sets used in this work are double-ζset augmented with polarization functions and sets of diffusing functions, denoted as DZP++.For MBz, TiBz^- and VBz^-, the ground sate structures are presented to be“half-sandwich geometries”;for CrBz^-,the ground state structure changes obviously named as“windbell structures”. For M（Bz）₂ and its anion M（Bz）₂^-, the ground sate structures are presented to be“multiple-decker structures”with the D6h symmetry. For Ti₂Bz and its anion Ti₂Bz^-, the two Ti atoms approximately parallel with the distorted benzene plane; for V₂Bz and its anion V₂Bz^-, the two V atoms are perpendicular to the benzene plane; for Cr₂Bz, the two Cr atoms are inclined over the benzene molecule, and for Cr₂Bz^- the two Cr atoms are perpendicular to the benzene plane. For Ti₂（Bz）₂, V₂（Bz）₂ and their anions Ti₂（Bz）₂^-, V₂（Bz）₂^-, the ground sate structures are presented to be“oyster-like structures”;the geometry of Cr₂（Bz）₂ is“multiple-decker structures”, and that of Cr₂（Bz）₂^- is“windbell structures”. The spin multiplicities of MBz, M₂Bz, M（Bz）₂ and M₂（Bz）₂ systems are very different from each other. The adiabatic electron affinity （AEA） with and without ZPVE correction, the vertical electron affinity （VEA）, and the vertical detachment energy （VDE） of these complexes are evaluated. The theoretical AEA predicted is in agreement with the limited experimental data. The mean bond dissociation energies for all of neutral Mn（Bz）m complexes are also calculated to examine their relative stabilities. The orders of stability of M_n（Bz）_m （M=Ti, V, Cr, n≤₂, m≤₂, Bz=benzene） complexes are M（Bz）₂ > M₂（Bz）₂ > M₂Bz > MBz and Ti_n（Bz）_m > V_n（Bz）_m > Cr_n（Bz）_m. The dipole moments are also presented.