REACTION OF DIIODOTRIORGANOPHOSPHORUS COMPOUNDS WITH DICOBALTOCTACARBONYL - ISOLATION OF A NEW ISOMERIC FORM OF [R(3)PI][COI3(PR(3))]

The novel reaction of R(3)PI compounds with dicobalt octacarbonyl has been investigated and compared to previous studies involving the react ion of R(3)PI(2) compounds with cobalt metal powders. The products pro duced from both reactions have identical stoichiometries but, surprisi ngly, possess different structures. Infrared and Raman spectroscopic s tudies and X-ray powder diffraction clearly show that the products obt ained from the reaction of R(2)PI(2) with Co-2(CO)(8) are a new isomer ic form of [R(3)PI][CoI3(PR(3))], compared to the products isolated fr om the reaction of R(3)PI(2) with cobalt metal powder. Seven examples of this new isomeric form of [R(3)PI][CoI3(PR(3))] are reported and ha ve been characterised by elemental analysis, Raman and quantitative el ectronic spectroscopy and magnetic data, the latter indicating that so me antiferromagnetic coupling occurs. Some general investigations into the reaction mechanism for these reactions are reported acid discusse d.