Reactivity of [ClCCo3(CO)9] with Metal Iron Carbonyl Clusters. Formation of Carbide and Dicarbide Mixed Metal Clusters

Abstract

The reaction of [ClCCo3(CO)9] with (PPh4)2[Fe3(CO)11] in CH2Cl2 at room temperature in the presence of thallium salt gives the brown cluster complex (PPh4)[Co5Fe(C2)(CO)17] (1), on which X-ray crystal structure determination has been carried out. The anion of 1 consists of two distorted Co3C and Co2FeC tetrahedra linked by a C−C bond (dicarbide unit) and by a Co−Co bond. The reactivity of [ClCCo3(CO)9] with the anions [Fe4C(CO)12]2- and [Fe5C(CO)14]2- was tested, giving [Fe4CoC(CO)14]2- and [Fe5CoC(CO)16]2-, respectively, as major products. Addition of [ClCCo3(CO)9] to a solution of [Fe3(CO)9(CCO)]2- in CH2Cl2, in the presence of thallium salt, generates the species [{Co3(CO)9}C{Fe3(CO)9(CCO)}]- (2). Subsequent addition of ethanol affords the hexametallic complex (PPh4)2[{Co3(CO)9}C{Fe3(CO)9(CCO2C2H5)}] (3), which reacts with ClAuPPh3 in a 1:3 molar ratio, in the presence of thallium salt, to form the cluster [{AuPPh3}3Fe3(CO)9(CCO2C2H5)] (4). According to its X-ray crystal determination, the anion of 4 can be described as a 48-electron Fe3 equilateral triangle capped on both sides by a μ3-CCO2C2H5 group and a AuPPh3 fragment. Additionally, two AuPPh3 units cap Fe2Au faces.