PENTANUCLEAR OXOALKOXIDE CLUSTERS OF SCANDIUM, YTTRIUM, INDIUM AND YTTERBIUM, X-RAY CRYSTAL-STRUCTURES OF [M5(MU5-O)(MU3-OPRI)4 (MU2-OPRI)4(OPRI)5] (M = IN, YB)

Attempts to prepare the metal tri-isopropoxides M(OPri)3 (M = Sc, Y, In, Yb) by various methods always produced the pentanuclear oxoalkoxide clusters [M5(μ5-O)(μ3-OPri)4(μ2-OPri)4(OPri)5] as the stable products. X-ray single crystal diffraction showed (M = In, Yb) the presence of the μ5-oxygen atom bonded in a square pyramidal configuration to five metal atoms which had terminal isopropoxo groups trans to the oxo atom. The μ3- and μ2-isopropoxo groups contribute to the distorted octahedral coordination of each metal atom. The scandium, yttrium and ytterbium clusters could be sublimed in vacuo and gave mass spectra containing pentanuclear cluster ions.The 1H NMR spectra for each compound was consistent with the X-ray crystal structure and variable-temperature studies showed fluxionality in the indium complex. © 1990.