SELECTIVE ADDITION-REACTIONS OF BIFUNCTIONAL NEUTRAL PHOSPHENIUM ION COMPLEXES

The reaction of bifunctional neutral phosphenium ion complexes, containing a carbon-carbon triple bond next to a phosphorus-molybdenum multiple bond, with carbenes and to carbene isolobal organometallic fragments is discussed. So, the reaction of (R)(PhC = C)P = MoCp'(CO)2 (R = 2,4,6-tBu3C6H2O; Cp' = eta(5)-C5H5: 1a; Cp' = eta(5)-C5Me5: 1b) with CH2N2 (2) yields the three membered heterocyclic compound (R)(PhC = C) activated P-CH2-MoCp*(CO)2 (3). 3 reacts with Co2(CO)8 to afford complex {(R)[(eta(2)-C = CPh)Co2(CO)6]} activated P-CH2-MoCp*(CO)2 (5) in which the phenylethynyl building block is eta(2)-side-on coordinated to a Co2(CO)6 fragment. Similar to the reaction of 1 with 2, 1 forms with Fe2(CO)9 (6), compound (R)(PhC = C) activated P-Fe(CO)4-MoCp*(CO)2 (7). In 7 the PMo double bond is coordinated in a eta(2) fashion to the 16-electron organometallic fragment Fe(CO)4. Using an excess of 6 and a higher temperature, the phosphorus-alkynyl-carbon sigma-bond is cleaved, and cluster MoCp*Fe3(CO)8(mu(3)-PR)(C = CPh) (8) is formed. The reaction of 1 with Cr(CO)5(THF) yields 10, a complex, in which the PhC = C ligand is eta(2)-coordinated to Cp'(CO)2Mo, and the Cr(CO)5 group forms a dative bond with the phosphorus atom. All new compounds have been characterized by analytical as well as by spectroscopic data (IR, H-1, P-31, C-13 NMR, MS), compound 10 by an X-ray analysis.