Analogy of C-Pt and C-O Chemical Bonding in the Diatomic CPt and CO.

The conjugate-pair molecules of CO and CPt provide a prototype of the autogenic isolobal relationship between the O and Pt atoms that can rationalize the structure and reactivity trends of platinum carbides. Herein, the photoelectron detachment at 532 nm has been recorded for the gas-phase CPt^- by using the photoelectron velocity-map imaging spectroscopy. The vibrationally resolved ground-state transition reveals a wealth of information concerning the electronic ground states of CPt^0/-1. Although the triple bonding characters in both CPt and CO have fortified the autogenic isolobal relationship between O and Pt, further detailed bonding comparisons have revealed the subtle nuance in the triple bonding. The triple bonds of CO comprise one σ donor bond from the O atom to the C atom and two degenerate π electron-sharing bonds. In contrast, the triple bonds of CPt involve three dative bonds, including one σ donor bond from the C atom to the Pt atom and two degenerate π back-donation bonds from the Pt atom to the C atom.