Structural Characterization of N‐Methylpyridoxine (MePN; PN = Vitamin B6) and Its Diorganotin Complexes [SnR2(MePN‐H)]I (R = Me, Et, Bu and Ph)

For comparison with the corresponding pyridoxine complexes we have prepared dimethyl-, diethyl-, dibutyl- and diphenyltin(IV) complexes of N-methylpyridoxine (MePN). The compounds [SnMe2(MePN−H)]I (1), [SnEt2(MePN−H)]I (2), [SnBu2(MePN−H)]I (3) and [SnPh2(MePN−H)]I·H2O (4) were isolated and characterized by IR, Raman, Mossbauer, 1H, 13C and 119Sn NMR spectroscopy, and by EI and FAB mass spectrometry. The crystal structures of [HMePN]I and of compounds 1, 2·2H2O and 3 were determined by X-ray diffractometry. Their lattices contain dimeric [SnR2(MePN−H)]22+ units (R = Me, Et, Bu) in which two bridging-chelating methylpyridoxinato anions link pentacoordinate Sn atoms with coordination polyhedra closer to square pyramids than to trigonal bipyramids. NMR results show that the dimeric cations persist in (CD3)2SO. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)