DICHLORODIALKYLTIN COMPLEXES WITH 4-BROMOPYRAZOLE - THE CRYSTAL-STRUCTURE OF BIS(4-BROMOPYRAZOLE-N-2)DICHLORODIMETHYLTIN(IV)

4-Bromopyrazole, which is much less basic than the corresponding pyraz ole but with similar hydrogen-bonding acidity, gives stable solid hexa coordinate complexes with dimethyl- and divinyl-tindichloride. The cry stal structure of the, tl-ans-octahedral compound Sn(CH3)(2)Cl-2.2C(3) H(3)BrN(2) was determined by X-ray crystallography and refined to R = 0.030. Intra-molecular hydrogen bonds are probably responsible for the essentially coplanar orientation of the pyrazolic ring plane with the SnCl2N2 plane. The packing is stabilized by inter-molecular hydrogen bonding.