SOME HYDRIDOTRIS(3,5-DIMETHYLPYRAZOLYL)BORATE COMPLEXES OF ZINC, CADMIUM AND MERCURY - SYNTHETIC, STRUCTURAL AND NMR INVESTIGATIONS

Attempts to prepare 1 : 1 complexes, LCdX, where L* = hydridotris(3,5 -dimethylpyrazolyl)borate and X = Cl, I, met with limited success. Thu s, with X = Cl, CdL2 was a usual product, although the reactions were not always clean. An LCdI compound was prepared. By contrast, reacti ons of KL with HgCl2 gave L*HgCl cleanLy. The reactions of [(Ph3P)2Cd Cl2] or [(di-2-pyridylamine)CdCl2] with KL gave ''L*Cd(OH).H2O'' in a lcoholic media, whereas [(1,2-phenylenediamine)CdI2] on reaction with KL in CH2Cl2 gave CdL*2. KL* removed 18-crown-6 from [(18-crown-6)CdC l2] as [(18-crown-6)K]L. PhHgCl reacted with KL* in THF to give a pro duct of stoichiometry ''PhHgL . 0.5KCl''. Variable-temperature H-1 an d HG-199 NMR studies in CDCl3 gave data consistent with the equilibriu m PhHg+ + L- half arrow right over half arrow left PhHgL* with low te mperatures favouring the covalent form. Other NMR data are presented a nd discussed. The crystal structure of CdL 2 is reported, but severe disorder, with the molecule taking up two orientations about a 3BAR ax is, reduced the accuracy of the structure determination. The environme nt around cadmium is essentially octahedral with a slight trigonal dis tortion in one molecule (A), but not in the other (B). The Cd-N distan ces [2.36(l) in A, 2.43(2) angstrom in B] are in good agreement with t hose found in analogous cadmium complexes.