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Azido Derivatives of Low-Valent Group 14 Elements: Synthesis, Characterization, and Electronic Structure of [( n -Pr) 2 ATI]GeN 3 and [( n -Pr) 2 ATI]SnN 3 Featuring Heterobicyclic 10-π-Electron Ring Systems

2000; American Chemical Society; Volume: 39; Issue: 18 Linguagem: Inglês

10.1021/ic000545u

1520-510X

A.E. Ayers, Dennis S. Marynick, H. V. Rasika Dias,

Inorganic Chemistry and Materials

Treatment of THF solutions of [(n-Pr)2ATI]MCl (where [(n-Pr)2ATI]- = N-(n-propyl)-2-(n-propylamino)troponiminate; M = Ge and Sn) with sodium azide affords the compounds [(n-Pr)2ATI]MN3 in excellent yield. X-ray analyses revealed that these Ge(II) and Sn(II) compounds feature linear azide moieties and planar heterobicyclic C7N2M ring systems. Germanium and tin atoms adopt a pyramidal geometry. IR spectra of [(n-Pr)2ATI]GeN3 and [(n-Pr)2ATI]SnN3 display a nu asym(N3) band at 2048 and 2039 cm-1, respectively. DFT calculations on the corresponding methyl-substituted species demonstrate that the geometrical and electronic structure of these two species are very similar, and the dominant canonical form of the metal-azide moiety is M-N-N identical to N. The tin system is, as expected, slightly more ionic. A comparative CASSCF/DFT study on the model system H-Sn-N3 illustrates that the DFT approach is viable for the calculation of the structures of these species.