Structure determination and bonding properties of gas-phase OPt 2 - anion and its neutral form.

Using anion photoelectron spectroscopy and quantum chemical calculations, the structures and properties of OPt 2 -/0 are investigated. The vertical detachment energies (VDEs) of OPt 2 - are measured to be 3.28 eV and 3.23 eV through the use of 355 and 266 nm photons, respectively. The high experimental VDEs of OPt 2 - can be attributed to the strong Pt-Pt and Pt-O σ bonds and low orbital energy of the SOMO. It is found that neutral OPt 2 has an OPt 2 triangular structure with C 2v symmetry and 1 A 1 electronic state. In the neutral OPt 2 , the O atom interacts with the Pt 2 moiety by two 2c-2e PtO bonds, one 3c-2e Pt 2 O σ bond, and one 3c-2e Pt 2 O π bond. On the other hand, anionic OPt 2 adopts a Pt-Pt-O bent structure with C s symmetry and 2 A' electronic state. NPA and ELF analyses indicate charge transfer upon complexation from the metal atoms to the O atom. Chemical bonding analyses show that OPt 2 -/0 have the strong covalent Pt-Pt and Pt-O bonds, and neutral OPt 2 exhibits σ aromaticity and π antiaromaticity.