Intramolecular chalcogen-tin interactions in (o-MeE-C6H4)CH22SnPh2-nCln; E = S O CH2 n = 0 1 2 and intermolecular chlorine-tin interactions in the meta and para-methoxy isomers

摘要

Organotin(IV) compounds of the type [(o-MeE-C6H4)CH2]2SnPh2-nCln were synthesized, E = O, n = 0 (>1), n = 1 (>2), n = 2 (>3), E = S, n = 0 (>4), n = 1 (>5), n = 2 (>6) and E = CH2, n = 0 (>7), n = 1 (>8), n = 2 (>9). The dichloro compounds >3 and >6 have been investigated by single crystal X-ray diffraction and exhibit bi-capped tetrahedral geometry at the tin atom as a consequence of significant intramolecular Sn⋯O (>3) and Sn⋯S (>6) secondary bonding, in monomolecular units. Compound >3 when crystallized from a hexane/thf solvent mixture shows two different conformers, >3′ and >3″, in the crystal structure, >3′ has two equivalent Sn⋯O interactions, while >3″ has two non-equivalent Sn⋯O interactions. Upon recrystallization of >3 from hexane only a single structural form is observed, >3′. The Sn⋯E distances in >3′, 3″, and >6 are 71.3; 73.5, 72.9; and 76.3% of the ΣvdW radii, respectively. The meta and para-substituted isomers of >3 (10, 11) exhibit a distortion at the tin atom due to self-association via intermolecular Sn⋯Cl interactions resulting in polymeric structures. ¹¹⁹Sn NMR spectroscopy suggests that the intramolecular Sn⋯E interactions persist in solution for the dichloride compounds >3 and >6.