Structures and bonding properties of $CPt2−/$ and $CPt2H−/$⁠: Anion photoelectron spectroscopy and quantum chemical calculations

We present a combined anion photoelectron spectroscopic and quantum chemical investigation on the structures and bonding properties of CPt₂^−/0 and CPt₂H^−/0. The experimental vertical detachment energies of CPt₂⁻ and CPt₂H⁻ are measured to be 1.91 ± 0.08 and 3.54 ± 0.08 eV, respectively. CPt₂⁻ is identified as a C_2v symmetric Pt—C—Pt bent structure, and CPt₂ has a D_∞h symmetric Pt—C—Pt linear structure. Both anionic and neutral CPt₂H adopt a Pt—C—Pt—H chain-shaped structure, in which the ∠PtCPt and ∠CPtH bond angles of CPt₂H⁻ are larger than those of CPt₂H. The Pt—C bonds in CPt₂^−/0 and CPt₂H^−/0 exhibit covalent double bonding characters. The Pt=C bonds are much stronger than the C—H bond that may explain why the C atom CPt₂H^−/0 prefers to form Pt=C bonds rather than C—H bonds. It may also explain why platinum can insert into the C—H bond to activate the C—H bond as reported in the literature.