LIGAND SUBSTITUTION OF FeRu2(CO)12 AND Fe2Ru(CO)12 WITH TERTIARY PHOSPHINES AND PHOSPHITES

Article abstract of DOI:10.1016/0022-328X(84)80139-4

Ligand substitution of the mixed-metal clusters FeRu2(CO)12 and Fe2Ru(CO)12 with triphenylphosphine and trimethylphosphite has been studied.Mono- and di-substituted derivatives have been synthesized and characterized structurally.The following crystal and molecular structures are reported: Fe2Ru(CO)11PPh3: triclinic, space group P<*>1, a 9.203(2), b 11.903(3), c 15.117(4) Angstroem, α 81.54(2), β 87.28(2), γ 66.72(2) deg, Z = 2; Fe2Ru(CO)11P(OMe)3: orthorhombic, space group Pna2₁, a 17.220(5), b 14.572(4), c 8.708(6) Angstroem, Z = 4, FeRu2(CO)11PPh3: monoclinic, space group P2₁/n, a 11.435(3), b 16.034(5), c 16.642(4) Angstroem, β 93.35(2) deg, Z = 4; FeRu2(CO)10(PPh3)2: orthorhombic, space group Pccm, a 14.854(4), b 17.180(7), c 16.786(12) Angstroem, Z = 4.Ligand substitution is found to occur preferentially at the ruthenium centers of the FeRu2 and Fe2Ru clusters.Monosubstitution causes expansion of both of the clusters while the overall geometry is practically unchanged.Disubstitution of FeRu2(CO)12 causes contraction of the cluster and leads to a formation of carbonyl bridges.The structurall trends have been interpreted in terms of electronic and packing effects of ligand substitution.The X-ray structures of Fe2Ru(CO)12 and FeRu2(CO)12 are not known; the ligand substitution studies indicate that Fe2Ru(CO)12 has the same structure as Fe3(CO)12, and that FeRu2(CO)12 does not have a Ru3(CO)12 structure as postulated previously from the IR studies.