Reactions of Laser-Ablated Chromium Atoms, Cations, and Electrons with CO in Excess Argon and Neon: Infrared Spectra and Density Functional Calculations on Neutral and Charged Unsaturated Chromium Carbonyls

Abstract

Laser-ablated Cr atoms react with CO (12C16O, 13C16O, 12C18O) in excess argon to give the same Cr(CO)3,4,5 species observed from the photodissociation of Cr(CO)6. Similar reactions in excess neon give neon matrix fundamentals between argon matrix and gas-phase values. The dicarbonyl Cr(CO)2 is bent with 1970.8, 1821.5 cm-1 and 1982.1, 1832.9 cm-1 C−O stretching fundamentals in solid argon and neon, respectively. The high-spin CrCO molecule appears at 1975.6 and 2018.4 cm-1 in solid argon and neon, respectively, and exhibits a strong matrix interaction. The CrCO+ cation and Cr(CO)2- anion are observed in laser-ablation experiments in solid neon at 2200.7 and 1705.0 cm-1, respectively. The Cr2(CO)2 complex absorbs strongly at 1735.4 cm-1 and gives several combination bands in neon. Density functional theory calculations support the vibrational assignments.