Experimental and theoretical study of the reaction of difluorostannylene with methyl chloride. The first direct IR spectroscopic detection of a complex between a carbene analog and an alkyl halide in low temperature inert matrix

Complex between a carbene analog (SnF₂) and organo halide (CH₃Cl) was stabilized by a low-temperature (Ar, 12 K) matrix isolation technique and characterized by IR spectroscopy for the first time. The bands at 567 and 543 cm^–1 were assigned to this complex. The potential energy surface of the system SnF₂ + CH₃CI was studied byab initio MP2/ 3-21G(d)//HF/3-21G(d) and semiempirical PM3 methods. Calculations shown that the reaction between SnF₂ and CH₃C1 results in the formation of a donor-acceptor complex. The calculated energy of the complex formation is 14.2 kcal mol^–1 (ab initio) and 15.7 kcal mol^–1 (PM3). Quantum-chemical calculations were used to interpret the IR spectrum of the complex. Insertion of SnF₂ into the C-Cl bond with formation of CH₃SnF₂Cl is an energetically favored process but it requires surpassing of a high energetic barrier and does not occur under the experimental conditions. A complex of CH₃CI with H₂O codeposited in argon matrix was detected by IR spectroscopy for the first time.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1121–1128, May, 1996.