Molecular Structure, Spectroscopy and Matrix Photochemistry of Fluorocarbonyl Iodide, FC(O)I

The molecular structure of FC(O)I has been determined by gas electron diffraction. High‐level ab initio methods, including coupled‐cluster and the new correlation‐consistent basis sets for fourth row elements, have been used to calculate the structure of FC(O)I. A comprehensive vibrational spectroscopic study (both IR and Raman) complemented by high‐level calculations has also been performed. Furthermore, UV, mass, and NMR spectra have been recorded for FC(O)I. The matrix photochemistry of FC(O)I has been studied with a low‐pressure mercury lamp and with a high‐pressure xenon lamp in combination with interference and cut‐off filters. UV photolysis revealed the formation of the OC⋅⋅⋅IF and OC⋅⋅⋅FI complexes and further photolysis of these complexes at λ>320 nm resulted in a re‐formation of FC(O)I. The structural conformation of the complexes has been characterized by comparing shifts in their CO and IF vibrational modes with respect to those of the free species. The structures, vibrational properties, and stability of the complexes were analyzed with the aid of coupled‐cluster ab initio calculations. The possible isomers of CFIO have been fully characterized. The complexes CO⋅⋅⋅IF were generated in situ by photolysis of FC(O)I in argon matrices (see scheme).