Investigations on the Reactivity of Li/Cl Phosphinidenoid Tungsten Complexes toward Various Iodine Compounds

Reactivity studies of Li/Cl phosphinidenoid W(CO)₅ complexes 2a,b toward various iodine compounds are reported. Transiently generated complexes 2a,b yielded no selective reactions with 3-, 9-, and 9,12-diiodo o-carbaboranes 3a−c, whereas clean transfer-iodination reaction occurred with C-iodo-substituted o-carbaboranes 3d,e, thus giving chloro(iodo)phosphane complex 6a in the case of 2a. Complex 2a was also reacted with iodo(phenyl)acetylene to yield complexes 6a, 8, and 9 in competing reactions. An independent pathway to chloro(iodo)phosphane complexes 6a,b was reaction of complexes 2a,b with elemental iodine at low temperature. All compounds were unambiguously characterized by elemental analysis, multinuclear NMR, IR, MS studies, and, in the case of 6a and 9, single-crystal X-ray diffraction.