Organomercury compounds. VII. Complexes of arylmercuric halides with bidentate ligands

Abstract

The complexes, C₆F₅HgXL₂ [X = Br or C1; L₂ = 2,2'-bipyridyl (bipy), 1,l0-phenanthroline (phen), 3,4,7,8-tetramethyl-1,l0-phenanthroline (tmp), or 2,9-dimethyl-1,l0-phenanthroline (dmp)], C₆Cl5HgClL₂ (L, = phen, tmp, or dmp), and PhHgClL₂ (L₂ = phen or tmp), have been prepared, but attempts to prepare PhHgCl bipy or complexes of phenylmercuric bromide were unsuccessful. Evidence that the complexes contain four coordinate mercury has been obtained from infrared spectroscopy. All complexes, except C₆Cl5HgCl phen, C₆Cl₅HgCl dmp, and PhHgCl tmp, undergo complete or partial disproportionation reactions, 2RHgXL₂ → L₂HgX₂ +R₂HgL₂ (or R₂Hg + L₂), in boiling benzene. Although disproportionation or low solubility precludes solution studies on the majority of the derivatives, it has been shown that C₆F₅HgX dmp complexes are monomeric in acetone and that PhHgCl phen undergoes dissociation, PhHgCl phen + PhHgCl + phen, in this solvent. Four-coordinate complexes of mercuric halides with neutral ligands, L,HgX, (L = a neutral unidentate or L, = a neutral bidentate ligand; X = C1, Br, or I), are well kno~n,l-~ but analogous complexes of organomercuric halides, viz. RHgXL,, were unknown prior to this investigation. Reactions of organomercuric halides with ligands generally result in disproportionation, the corresponding diorganomercurial and mercuric halide complex being f~rmed.~-~ In some cases intermediate complexes RHgL+X- have been i~olated~,~ or detected in soluti~n,~-~~ and a 1 : 1 complex of unknown structure between pyridine and cis-2- * Part VI, J. organomet. Chem., in press. Preliminary communications for Part VII: Canty, A. J., Deacon, G. B., and Felder, P. W., Inorg. nzlcl. Chem. Lett., 1967,3,263; Deacon, G. B., and Canty, A. J., Inorg. %ucl. Chem. Lett., 1968, 4, 128. t Chemistry Department, Monash University, Clayton, Vie. 3168. Evans, R. C., Mann, F. G., Peiser, H. S., and Purdie, D., J. chem. Soc., 1940, 1209. Cass, R. C., Coates, G. E., and Hayter, R. G., J. chem. Soc., 1955, 4007. Coates, G. E., and Ridley, D., J. chem. Soc., 1964, 166. Coates, G. E. "Organometallic Compounds." 2nd. Edn, pp. 78-82. (Methuen: London 1960.) Seyferth, D., and Towe, R. H., Inorg. Chem., 1962, 1, 185. Coates, G. E., and Lauder, A., J. chem. Soc., 1965, 1857. Brodersen, K., Chem. Ber., 1957, 90, 2703. Schwarzenbach, G., and Schellenberg, &I., Helv. chim. Acta, 1965, 48, 28. Goggin, P. L., and Woodward, L. A., Trans. Faraday Soc., 1962, 58, 1495. Dessy, R. E., Budde, W. L., and Woodruff, C., J. Am. chem. Soc., 1962, 84, 1172. Aust. J. Chem., 1968, 21, 1757-67