Matrix IR-spectroscopic and quantum-chemical study of difluorostannylene complexation with dinitrogen

Complexes of difluorostannylene with dinitrogen of composition 1∶1 and 1∶2 were stabilized in Ar matrix (12 K) and characterized by IR spectra. The bands at 588, 565, and 583, 557 cm⁻¹, respectively, were assigned to these complexes. Potential energy surfaces of the systems SnF₂+N₂ and SnF₂+2N₂ were studied by theab initio MP2/3-21G(d2)//HF/3-21G(d2) method using the basis set including polarization functions at Sn, F, and N atoms. Equilibrium structures of the complexes haveC _s andC _2v symmetry and correspond to coordination of lone electron pairs of nitrogen molecules with vacant p-AO of the carbenic center. The calculated complexation energies are equal to 4.6 and 8.9 kcal mol⁻¹, respectively. Based on results of quantum-chemical calculations an interpretation of the IR spectra of the complexes was given and it was shown that cycloaddition of SnF₂ to a triple N≡N bond with formation ofcyclo-SnF₂N₂ is energetically unfavorable. The absorption band belonging to SiF₄·N₂ complex in Ar matrix was detected and assigned. Dedicated to the memory of Academician M. E. Vol'pin timed to his 75th birthday. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1087–1093, June, 1998.