Synthesis and characterization of tin complexes [Sn(L)Hal4] (L = N-alkyl-(pyridin-2-yl)aldimine; Hal = Cl, Br): A structural study

Abstract

The reactions of the ligands N-methyl-(pyridin-2-yl)aldimine (a), N-ethyl-(pyridin-2-yl)aldimine (b), and N-benzyl-(pyridin-2-yl)aldimine (c) with SnCl4 and SnBr4 led to the formation of compounds [Sn{(C5H4N)HCNMe}Cl4] (1), [Sn{(C5H4N)HCNMe}Br4] (2), [Sn{(C5H4N)HCNEt}Cl4] (3), [Sn{(C5H4N)HCNEt}Br4] (4), [Sn{(C5H4N)HCNBn}Cl4] (5), and [Sn{(C5H4N)HCNBn}Br4] (6) in good yields. All the compounds were characterized by 1H, 13C{1H}, and 119Sn{1H} NMR, vibrational IR-Raman spectroscopy, elemental analyses, and X-ray diffraction analysis. The structural studies confirmed the formation of the respective six-coordinate tin complexes as a result of the chelation of the iminic and pyridinic nitrogen atoms of the ligands towards the tin atom; the Sn–N distances were shortened as the Lewis acid character at the tin atom was increased. In all the molecular structures the tin atom displayed a distorted octahedral local geometry.