SYNTHESIS AND SPECTROSCOPIC INVESTIGATIONS (IR, NMR AND MOSSBAUER) OF TIN(IV) AND ORGANOTIN(IV) DERIVATIVES OF BIS(PYRAZOL-1-YL) ALKANES - X-RAY CRYSTAL-STRUCTURES OF BIS(4-METHYLPYRAZOL-1-YL) METHANE AND ITS DIMETHYLTIN(IV) DICHLORIDE ADDUCT

A series of 1:1 adducts of the type [(L)R(n)SnX(4-n)] . zH(2)O (L = bis(4-methylpyrazol-1-yl)methane (L(4)), bis(3,4,5-trimethylpyrazol-1-yl)methane (L(T)), 1,2-bis(pyrazol-1-yl)ethane (L(A)) or 1,2-bis(3,5-dimethylpyrazol-1-yl)ethane (L(B)); R = Me, Et, Bu or Ph; X = I, Br or Cl; n = 0, 1 or 2; z = 1, 1.5 or 2), and the likely polynuclear [(L(A))(5)(SnCl4)(4)] . (H2O)(5) and [(L(B))(2)(SnCl4)(3)] . 1/2[Et(2)O] have been characterized in the solid state and in solution by analyses, spectral (IR, Mossbauer, and H-1, C-13 and Sn-119 NMR) data and conductivity measurements. When L(T) reacts with SnCl4, cleavage of a carbon (sp(3))-nitrogen bond was observed and the adduct [(3,4,5-trimethylpyrazole)(2)SnCl4] was obtained. The diorganotin(IV) complexes generally dissociate in chloroform or in acetone solution, while the trichlorotin(IV) and tetrachlorotin(IV) adducts probably retain the hexacoordinate configuration. The crystal structures of L(4) and of the adduct [(L(4))(CH3)(2)SnCl2] have been determined by X-ray analysis. In the adduct the tin atom is coordinated to two halide atoms, two methyl groups and two N atoms, with trans-(CH3)(2)Sn in a slightly distorted octahedral configuration. The long Sn-N bond distance (2.436(6)Angstrom) indicates weak donor ability of the N-2 donor L(4). Comparison is made with the X-ray crystal structures of several R(2)SnX(2)N(2)-type compounds.