Theoretical study of the structure, bonding and electronic behaviour of sandwich complexes [M3(C7H7)2X3]− (M = Ni, Pd, Pt; X = F, Cl)

The correlations between the structural and electronic properties of the clusters [M3X3]3− and sandwich complexes [M3(C7H7)2X3]− (where M = Ni, Pd, Pt; X = F, Cl) were studied with density functional theory (B3PW91). All of the sandwich complexes are donating and back-donating metal–ligand bonding structures. The influence of the ligand, significant variations in the MC, MX, MM, CC bond lengths and binding energies were examined to obtain qualitative and quantitative pictures of the intramolecular C7R7+–M3X33− interactions. Our theoretical investigations show that the binding energies of the sandwich complexes gradually reduce from Ni to Pt, as well as from F to Cl. Meanwhile, the geometric and electronic structures and the relative stabilities have a strong relation to each other.