CHEMISTRY OF METAL-CARBONYLS AND CYANIDE COMPLEXES IN LIQUID-AMMONIA .33. SYNTHESIS OF NEW CARBAMOYLCARBONYL COMPLEXES FROM KNOWN AND NEW CATIONIC CARBONYL-COMPLEXES OF MANGANESE AND RHENIUM

The covalent carbamoyl carbonyl compounds Re(CO)5COHN2, cis-M(CO)4(L)CONH2, M(CO)3(L)2CONH2 and M(CO)3(D)CONH2 (M = Mn, Re; L = PPh3, PEt3; D = bipy, phen) are formed by reactions of the cationic complexes [Re(CO)6]+, [M(CO)5L]+, [M(CO)4L2]+ and [M(CO)4D]+ (M = Mn, Re; L = PPh3, PEt3; D = bipy, phen) with liquid NH3 with concomitant deprotonation: [M(CO)6-nLn]+ + 2 NH3 → M(CO)5-nLnCONH2 + NH4+ (n = 0, 1, 2) and [M(CO)4D]+ + 2 NH3 → M(CO)3(D)CONH2 + NH4+ The stability of the above-mentioned carbamoyl carbonyl complexes increases from the penta- to the tetra- to the tri-carbonyl derivatives. In all cases the rhenium compounds are much more stable than the corresponding manganese complexes. Whereas the carbamoyl compound Re(CO)4(PEt3)CONH2 can be isolated by reaction of [Re(CO)5PEt3]+ with NH3, the corresponding manganese complex undergoes Hofmann degradation of amides even at -70°C to form HMn(CO)4PEt3 and NH4NCO. The IR and some mass and 1H NMR spectra of the new hexacoordinated carbamoyl carbonyl complexes are discussed and the reactions of these compounds with liquid NH3, HCl and CH3OH are described. © 1978.