Reactions of CO2 with Cu(I) alkoxides and amides to give alkylcarbonato-μ-carbonato-, hydrogencarbonato-, and carbamato-copper complexes

Abstract

Carbon dioxide reacts with ROCu(PPh3)2 (R=C2H5, C6H5CH2; PPh3 = triphenylphosphine) to produce ROCO2Cu(PPh3)2. Hydrolysis or thermolysis of the alkylcarbonatocopper(I) complexes gives a binuclear carbon-atocopper(I) complex (PPh3)2CuOCO2Cu(PPh3)2, which is further converted into a hydrogencarbonatocopper-(I) complex [HOCO2Cu(PPh3)2]n by the reaction with CO2 in moist solvents. The IR spectrum of [HOCO2-Cu(PPh3)2]n shows association of the HOCO2Cu(PPh3)2 units through hydrogen bonds. The IR spectrum of [HOCO2Cu(PPh3)2]n also reveals that the mode of the association depends on conditions of the crystallization of the complex. The reaction of (PPh3)2CuOCO2Cu(PPh3)2 with CH3I gives (CH3O)2CO and the reaction of [HOCO2Cu(PPh3)2]n with C6H5NH2 affords C6H5NHCO2Cu(PPh3)2 in high yields. Carbon dioxide reacts also with an amidocopper(I) complex C6H5NHCu(PPh3)2 to yield a carbamatocopper(I) complex C6H5NHCO2GU-(PPh3)2. The reaction of CH3Cu(PPh3)2(diethyl ether)o.5 with CO2 in the presence of HN(C2H5)2 affords (C2H5)2NHCO2Cu(PPh3)2. The isocyanate group of phenyl isocyanate is inserted into the C2H5O-CU bond of C2H5OCu(PPh3)2 to give a (ethyl iV-phenylcarbamato) copper complex.