SYNTHESIS AND REACTIVITY OF PHENYLETHYNYL SUBSTITUTED PHOSPHENIUM ION COMPLEXES - SYNTHESIS OF CLUSTER COMPOUNDS WITH A 1-COBALTA-2-PHOSPHAHETEROALLYL BUILDING BLOCK

The synthesis of the phenylethinyl-chlorophosphines (R)(Cl)P(CCPh) (R = 2,6-tBu2-4-MeC6H2O: IVa; R = 2,4,6-tBu3C6H2O: IVb) is described. IV reacts with Cp′(CO)3Mo-, VII, (Cp′ = η5-C5H5, η5-C5Me5) to yield bifunctionalized terminal phosphenium-ion complexes of the type (R)(Ph-CC)PMoCp′(CO)2 (R = 2,6-tBu2-4-MeC6H2O, Cp′ = η5-C5H5: IIa; R = 2,4,6-tBu3C6H2O, η5-C5H5: IIc, Cp′ = η5-C5Me5: IId). The compounds II contain a trigonal planar coordinated phosphorus atom, which is part of a phosphorus-molybdenum double bond system. The reaction of II with dicobaltoctacarbonyl, V, gives the complexes [(η2-CCPh)Co2(CO)6](R)PMo (η5-C5H5)(CO)2 (R = 2,6-tBu2-4-MeC6H2O: VIIIa; R = 2,4,6-tBu3C6H2O: VIIIb) and the cluster compounds {A figure is presented} (R = 2,6-tBu2-4-MeC6H2O: IXa; R = 2,4,6-tBu3C6H2O: IXb), in which the phenylethinyl ligand, in contrast to II, is π-side-on coordinated to a Co2(CO)6 (VIIIa, VIIIb) or to a (CO)2CoMo(η5-C5Me5)(CO)2 (IXa, IXb) fragment. The complexes IX contain a 1-cobalta-2-phospha heteroallyl building block. All new compounds are documented by analytical and spectroscopic (IR, MS, 1H-, 13C-, 31P-NMR) data as well as by an X-ray diffraction study of IXb. © 1990.