Study of the Nucleophilic Addition of Alcoholates on cis-Fe(R)(R‘)(CO)3L (R, R‘ = Alkyl, Alkoxycarbonyl, Alkyloxalyl; L = CO, P(OEt)3) and the First Characterization of a Tris(alkoxycarbonyl) Complex: K[Fe(CO2tBu)3(CO)3

Abstract

The nucleophilic additions of alcoholates (MeONa or tBuOK) on the complexes cis-Fe(R)(R‘)(CO)3L (R, R‘ = CO2Me, CO2tBu, CH2CO2Me, COCO2Me; L = CO, P(OEt)3) occur at one terminal carbonyl ligand to give the new [Fe(R)(R‘)(CO2R‘‘)(CO)2L]- anions. No transesterification (via addition at an alkoxycarbonyl ligand) is observed. An X-ray diffraction study gives the space group P21/c for K[Fe(CO2tBu)3(CO)3] (resulting from the addition of KOtBu on Fe(CO2tBu)2(CO)4), which is better described as the dimer K2Fe2(CO2tBu)6(CO)6·H2O·THF.