Tin(IV) and organotin(IV) complexes containing mono or bidentate N-donor ligands - III. 1-methylimidazole derivatives: synthesis, spectroscopic and structural characterization

A series of adducts of the type [(L-#)(y)RnSnX4-n] . zH(2)O (L-# = 1-methylimidazole, y = 1 or 2, R = Me, Et, Bu-n or Ph, n = 1, 2 or 3, X = Cl, Br or I, z = 0, 1/2 or 1) has been characterized in the solid state and in solution by analyses, spectral (IR, Sn-119 Mossbauer, and H-1, C-13 and Sn-119 NMR) data and conductivity measurements. The molecular weight determinations and the NMR data indicate that these organotin(IV) complexes partly dissociate in chloroform and acetone solution. The donor L-# interacts with [(CH3)(3)SnNO3], yielding the 2:1 ionic complex [(L-#)(2)(CH3)(3)Sn]NO3. The derivative [(L-#)(2)(CH3)(2)SnCl2] reacts with NaClO4, AgNO3, NaBPh4 and KSCN in ethanol and diethyl ether giving the complexes [(L-#)(2)(CH3)(2)Sn(ClO4)(2)], [(L-#)(CH3)(2)Sn(NO3)(2)(H2O)], [(L-#)(CH3)(2)SnCl(H2O)(2)]BPh4 and [(L-#)(2)(CH3)(2)Sn(NCS)(2)], respectively, whereas when [(L-#)(CH3)(3)SnCl] interacts with an equimolar quantity of NaClO4, [(L-#)(2)(CH3)(3)Sn]ClO4 . 1/2H(2)O and (CH3)(3)Sn(ClO4) in 1:1 ratio are obtained. The stability towards self-decomposition of the complexes obtained decreases with increasing number of the Sn-bonded aryl or alkyl groups. The derivative [(L-#)(2)(CH3)(2)SnBr2] reacts with 1,10-phenanthroline (Phen), yielding immediately the complex [(Phen)(CH3)(2)SnBr2], whereas from the reaction between [(L-#)(2)(CH3)(2)Sn(ClO4)(2)] and Phen, the mixed ligand complex [(L-#)(Phen)(CH3)(2)Sn](ClO4)(2) is obtained. A different behaviour has been shown from the diiodide complex [(L-#)(2)(C2H5)(2)SnI2] which reacts with Phen, yielding the compound with the 3:2 stoichiometry [(Phen)(3){(C2H5)(2)SnI2}(2)]. Both the crystal structures of [(L-#)(2)(CH3)(2)SnBr2] and [(L-#)(2)(C2H5)(2)SnI2] show the tin atom in an all-trans octahedral regular configuration, whereas in [(L-#)(C6H5)(3)SnCl] the tin atom exhibits a distorted trigonal bipyramidal geometry, with the phenyl groups in the equatorial positions. A comparison was made with structural data of other R3SnXN-type derivatives. The molecular parameters of 1-methylimidazole in the tin(IV) complexes were used, together with other structural data in literature, to derive empirical rules concerning the imidazole donor. (C) 1998 Elsevier Science S.A.