Synthesis, and 19F NMR and X-ray structural studies of triosmium clusters (μ-H)Os3(CO)10L[ON(CF3)2] (L PPh3, AsPh3 and SbPh3)

Abstract

Bis(trifluoromethyl)nitroxyl radical reacts with H2Os3(CO)10L (L PPh3, AsPh3, SbPh3) to afford the derivatives (μ-H)Os3(CO)10L[ON(CF3)2] in which the (CF3)2NO moiety is revealed by single crystal X-ray determinations to assume an axial position. Variable-temperature 19F NMR spectral studies indicate that the two CF3 groups of the(CF3)2N moiety become magnetically different at lower temperature due to restricted rotation about the NO bond. The activation energies estimated from the coalescence temperatures are 54.4 and 52.3 kJ/mole for (μ-H)Os3(CO)10PPh3[ON(CF3)2] and for (μ-H)Os3(CO)10AsPh2-[ON(CF3)2] respectively. © 1993.