Synthesis and crystal structures of heterobimetallic Fe-Cd, Fe-Zn, and Fe-In complexes containing hemilabile phosphorus/oxygen and silicon/oxygen bridging ligands

Abstract

The reactions of K[Fe{Si(OMe)3}(CO)3(P∼Y)][P∼Y=Ph2PCH2C(O)Ph, Ph2PCH2C(O)[(η-C5H4)FeCp] (Cp=η5-C5H5), Ph2P(CH2)2CN] with CdCl2·2.5H2O, ZnX2 (X=Cl, I) or InCl3 afforded Fe-Cd-Fe or Fe-M(μ-X)2M-Fe (M=Cd, Zn, In;X=Cl, I) and Fe-InCl2 complexes. Some of them contain an unusual and labile μ-η2-SiO alkoxysilyl bridge which may be associated with a bridging mode for the ketophosphine ligand (first such example structurally established), thus providing original results in bimetallic chemistry on the intramolecular coordination of oxygendonor functions ofchemically different hemilabile ligands firmly attached to a neighboring metal center. The structures of the trinuclear complex (3), of the chlorobenzene solvate of the tetranuclear complex (4a·C6H5Cl) and of [mer-(OC)3{(EtO)3Si} (4e) have been determined by X-ray diffraction. Crystals of 3 are orthorhombic, space groupPbcn, witha=19.010(4),b=11.766(5),c=26.998(7)A, andZ=4. Crystals of4a·C6H5Cl are monoclinic, space groupC2/c witha=22.455(3),b=17.680(2),c=16.627(4)A, β=90.80(4)°, andZ=4. Crystals of4e are monoclinic, space groupC2/c witha=25.392(5),b=18.554(6),c=16.28(1)A, β=120.73(3)°, andZ=4. The structures were solved using direct methods and Fourier difference techniques and refined by blocked full-matrix least squares toR=0.035 (Rw=0.049) for 2719 observed reflections, toR=0.042 (Rw=0.056) for 3082 observed reflections, and toR=0.057 (Rw=0.075) for 1850 observed reflections for3, 4a·C6H5Cl and4e, respectively. The Fe-Zn complexes (9a), (9b) and (9c) were prepared and characterized by spectroscopic methods.