Synthesis, spectroscopic and structural aspects of some tetraorganodistannoxanes with internally functionalized oxime: crystal and molecular structures of [{R2Sn(ONC(Me)py)}2O]2 (R=Bun and Et) and 2-NC5H4C(Me)NOH

Diorganotin(IV) complexes of the type [{R2Sn(ON=C(Me)py)}(2)O](2)(R = Bu-n(1), Pr-n(2), Et (3) and Me (4)) have been synthesized by the condensation reaction of R2SnO with 2-NC5H4(Me)C=NOH (5) in 1:1 molar ratio in refluxing anhydrous benzene-toluene and characterized by elemental analyses and IR and NMR (H-1, C-13 and Sn-119) spectroscopy. Two sets of Sn-119 chemical shifts are observed in the Sn-119-NMR spectra of all of these compounds indicating the presence of two types of environment around the tin atoms in solution. The crystal structures of 1, 3 and 5 have been established by single crystal X-ray diffraction, The bonding in 1 differs from that in 3 but in both structures two different environments around the tin atoms are evident with the geometry around each tin atom being that of a distorted trigonal bipyramid with alkyl groups at the equatorial positions. The structure of 5 consists of chains of molecules arising from intermolecular hydrogen bonding involving the nitrogen atom of the ring.