Synthesis and characterization of new rhodium–cobalt mixed-metal octahedral linked clusters containing η2-diyne ligands

Six new RhCo mixed-metal linked cluster complexes [Rh2Co2(CO)8(μ-CO)2 (μ4,η2-HCCCH2O)]2R (R=C6H4-1,4 (1); C6H4-1,4(C(O))2 (2); (C(O)CH2)2 (3); (C(O)CH)2 (4); (C(O))2CH2 (5); (C(O))2 (6)) have been synthesized from reactions of [Rh2Co2(CO)12] (7) with the appropriate diyne compounds [(HCCCH2CO)]2R (R=C6H4-1,4 (8); C6H4-1,4(C(O))2 (9); (C(O)CH2)2 (10); (C(O)CH)2 (11); (C(O))2CH2 (12); (C(O))2 (13)) in n-hexane at room temperature, respectively. The acetylene moieties of diyne ligands insert into the CoCo bonds of two tetranuclear clusters to give linked octahedral clusters containing two [Rh2Co2C2] units. The structure of cluster 1 was determined by single-crystal X-ray diffraction analysis and all clusters were characterized by elemental analysis (C/H), IR and 1H-NMR spectroscopy.