Salts of transition metal hydrocarbonyls.

The structures of HgFe(CO)4, CdFe(CO)4 and Fe (CO)4 (HgX)2 , which were originally reported in 1928-1929, have been determined by a study of their infra-red spectra and are shown to contain metal-metal bonds. The reaction of mercuric chloride with iron pentacarbonyl at low temperatures gave the reported Fe(CO)5HgCl2 and also a 1:2 adduct, Fe(CO)5 2HgCl2 . Treatment of substituted iron carbonyls with mercuric salts gave analogous complexes. with mono phosphine (arsine or stibine) iron tetracarbonyls, the products could not be identified but with the disubstituted derivatives Fe(CO)3 (Eph3 )2 , E = P, As, Sb., 1:1 adducts of the type Fe (CO)3 (Eph3 )2 HgX2 were isolated. The phosphite derivative gave a 1:2 adduct. The diolefin iron tricarbonyls, eg. norbornadiene iron tricarbon yl showed no reaction with mercuric chloride. Physical studies, in particular the infra-red spectra (2200-200 cm-1), showed that the 1:1 adducts are probably dimeric in the solid and dissociate in solution to the "parent" carbonyl, mercuric halide and an ionic species, Fe(CO)3 [P(OPh)3]2 2HgCl2 was a 1:1 electrolyte in solution. The infra-red spectra of the ''parent" substituted carbonyls were studied in detail. In view of the similarity of iron pentacarbonyl to cyclopentadienyl cobalt dicarbonyl the reactions of the latter with mercuric salts were investigated. Both 1:1 and 1:2 adducts, (C5H5)Co(CO)2 1 or 2 HgX2 were isolated. Physical studies support a dimeric structure in the solid containing mercury-cobalt bonds and bridging halogens. Dissociation occurs in solution. The donor property of Fe(CO)3 (PPh3 )a has been briefly investigated with other metal and non-metal salts. In the introduction to this thesis metal-metal bonded complexes are reviewed. Also included are compounds relevant to their preparation.