Synthesis and crystal structure of the mixed cluster (η-C 5H 5)NiFe 2(CO) 6C 2-t-Bu

Abstract

The title complex has been obtained by treating Fe 3(CO) 12 with (η-C 5H 5) 2Ni 2(HC 2t-Bu) in hydrocarbon solvents. The crystals are monoclinic, space group P2 1/a, with Z = 4 in a unit cell of dimensions: a = 13.716(9), b = 15.806(14), c = 8.979(8) Å, β = 104.0(1)°. The structure has been solved from diffractometer data by Patterson and Fourier methods and refined by full-matrix leastsquares to R = 0.048 for 1926 independent observed reflections. The structure of the complex consists of a triangular arrangement of two Fe and one Ni atoms, bonded to six terminal carbonyls (through Fe atoms only), to a cyclopentadienyl group (through the Ni atom) and to a rearranged t-butylacetylene (through all the metal atoms). The bonding of the alkyne to the metal atom cluster is similar to those reported for the homometallic derivatives Fe 3(CO) 9C 2Ph 2, (η-C 5H 5)Fe 3(CO) 7C 2Ph and HRu 3(CO) 9C 2t-Bu. In the cluster the Fe(2)Ni distance is considerably shorter (2.378 Å) than Fe(1)Ni (2.564 Å) and Fe(1)Fe(2) (2.610 Å). Deviations from the E.A.N. formalism are also observed in the present complex.