Other Developments Originating from the Study of Metal Carbonyls

OTHER DEVELOPMENTS ORIGINATING FROM THE STUDY OF METAL CARBONYLS 

Formation of Ni(CO)4 or Co(CO)4- by the cyanide method depends upon the stepwise substitution of the anion of the cyano complex by the iso-electronic carbon monoxide molecule. By treating Co2(CO)8 with potassium cyanide we obtained cyanocarbonyls of cobalt of low oxidation number (83). In reactions of the nitrosyl carbonyls of iron and cobalt, Behrens (86) substituted all the CO groups with CN to give K3[Co(NO)(CN)3] or 

K2[Fe(NO)2(CN)2]. My former co-worker R. Nast (83) showed that the reaction of carbon monoxide with K4[Ni2I(CN)6] and K4[Ni°(CN)4] in liquid ammonia gave nickel cyanocarbonyl complexes with monovalent and zero-valent metal atoms. The isoelectronic hexacyanoiron(III) or tetra-cyanonickel(II) complexes correspond to the cyanocarbonyls [Feu(CN)5 CO]3-, [Ni (CN)3CO]2-, or [Ni°(CN)2(CO)2]2-. Cobalt is analogous to nickel in forming the complex [Co(CN)3CO]2-. According to our earlier work, [Fe (CN)5CO]3- and [Fem(CN)6]3- are isosteric (87). Other structural investigations were concerned with tetracyano and tetracarbonyl complexes (88). 

Following our early studies (89, 90), we have recently investigated derivatives of manganese carbonyl obtained from reactions between Mn(CO)5X (X usually Br) and organic sulfur ligands (93). Manganese carbonyl chelate complexes are formed in which sulfur is covalently bonded to manganese, or forms a coordinate bond as an electron donor. 

Some Remarks Concerning Bridged Metal Carbonyl Compounds 

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VIII. Other Developments Originating from the Study of Metal Carbonyls 18... 

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