X-RAY PHOTOEMISSION-STUDY OF PLATINUM CARBONYL DIANIONS [PT3(CO)6]N2-(N=2,3,4,5,6, APPROXIMATELY 10)

A series of platinum carbonyl dianion clusters has been studied by X-ray photoemission spectroscopy. Members of the series include [Pt3(CO)6]n2- where n = 2, 3, 4, 5, 6, ~10. The general structure of all valence spectra, in particular that of the Pt 5d derived bands, is remarkably similar. This observation is taken to be evidence that negligible interaction exists between the Pt3(CO)6 layers. We observe changes in the binding energies of Pt 4f, Pt 4d, and the molecular orbitals (5σ + 1π) of the carbonyl ligands as a function of cluster size. All levels except the carbonyl 4σ orbitals are shifted to higher binding energy asymptotically as the cluster size increases. This behavior of binding energies is interpreted as being due to the decreasing effect of the anion charge in larger clusters and to the bonding character of the (5σ + 1π) orbitals. © 1979, American Chemical Society. All rights reserved.