Synthesis and structural characterisation of lanthanide and actinide phosphaorganometallic complexes derived from the 3,5-di-tert-butyl-1,2,4-triphospholyl ring anion, P3C2But−2: Crystal and molecular structures of [M(η5-P3C2But2)2(η2-P3C2But2)] (M = Sc,

Treatment of MI3 (M = Sc, Y, Tm, and U) with three equivalents of KP3C2But2 in refluxing toluene led to the corresponding monomeric, formally eight coordinate, complexes [M(η5-P3C2But2)2(η2-P3C2But2)] in moderate yields. In the solid state the complexes, which are all iso-structural, display an interesting assembly of ligands comprising of one η2-(bent) and two η5-ligated triphospholyl rings. NMR studies indicate that the complexes are fluxional in solution.