PLATINUM-CENTERED OCTAKIS(TRIPHENYLPHOSPHINO-GOLD) CLUSTERS - A RELATIVISTIC MO STUDY

The system of [Pt(CO)(AuPPh(3))(8)](2+) represents an example of the s pheroidal 18-electron cluster which consists of 283 atoms, 817 real-va lence orbitals, and, eventually, 1634 complex spin-orbitals. The above system was investigated by an MO-LCAO-SCF study at the all-valence (n onempirical) quasi-relativistic and relativistic CNDO/1 levels. Owing to the complexity of the system under study, instead of an orbital int eraction diagram, the density-of-state functions were generated. Their projections, obtained through net orbital populations, bear informati on about the positioning of MOs and eventual interaction of the AOs co mposing individual MOs. The platinum 5d orbitals exhibit a mixing with those of gold and contribute to only a few HOMOS; the rest of gold 5d orbitals, however, are situated at lower energies. (C) 1996 John Wile y & Sons, Inc.