Sequential Bond Energies of Pt(CO)x+ (x = 1 −4) Determined by Collision-Induced Dissociation

Abstract

The sequential bond energies of Pt(CO)x+ (x = 1−4) are determined by collision-induced dissociation with Xe using guided-ion beam tandem mass spectrometry. Analysis of the kinetic energy dependent cross sections yields 0 K bond energies in eV (kJ/mol) of 2.20 ± 0.10 (212 ± 10), 2.00 ± 0.10 (193 ± 10), 1.02 ± 0.05 (98 ± 5), and 0.55 ± 0.05 (53 ± 5) for (CO)x-1Pt+−CO with x = 1−4, respectively. These values are in reasonable agreement with results of density functional ab initio calculations in the literature. D0(Pt+−Xe) is determined as 0.86 ± 0.30 eV (83 ± 29 kJ/mol) from analysis of the ligand exchange reaction with PtCO+. The trend in these bond energies is compared with those of nickel and sodium carbonyl cations and discussed in terms of sdσ hybridization, electrostatic interactions, and ligand−ligand steric interactions.