Selektive Additionsreaktionen an bifunktionalen neutralen Phosphenium-Ion-Komplexen / Selective Addition Reactions of Bifunctional Neutral Phosphenium Ion Complexes

Abstract

Selective Addition Reactions, Bifunctional Neutral Phosphenium Ion ComplexesThe 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-'Bu3C6H20; Cp' = //5-C5H5: la; Cp' = ;;--CsMes: lb ) with CH^N2 (2) yields the three membered heterocyclic compound (R )(PhC =C )P-C H \-M oC p*(COh (3). 3 reacts with Co2(CO)8 to afford complex {(R)[(;;2-C=CPh)Co2(CO)6]}R -C IT-M oC p*(CO )2 (5) in which the phenylethynyl building block is >/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)P-Fe(CO)4-MoCp*(CO)2 (7). In 7 the PMo double bond is coordinated in a rf-fashion to the 16-electron organometallic fragment Fe(CO)4. Using an excess of 6 and a higher temperature, the phosphorus-alkynyl-carbon fj-bond is cleaved, and cluster MoCp*Fe3(CO)8(J u3-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 ^-coordinated to Cp'(CO)2Mo, and the Cr(CO)5 group forms a dative bond with the phospho rus atom.All new compounds have been characterized by analytical as well as by spectroscopic data (IR, 'H, 3IP, l3C NMR, MS), compound 10 by an X-ray analysis.

Reactions of Molybdenum and Tungsten Phosphenium Complexes with Sulfur and Selenium

“…The reactions of monochlorophosphanes, (X)(Y)PCl, with NaCpM(CO) 3 (M = Cr, Mo, W) produce, via salt elimination, the neutral metallophosphane complexes CpM(CO) 3 [P(X)(Y)] ( 1 ) (Scheme ). − The phosphorus atom in 1 is pyramidal, and the M−P bond is formally pure σ in character. Due to the Lewis basicity of the phosphane center and the lability of the CO ligands, examples of 1 tend to decarbonylate, forming neutral metallophosphenium complexes 2 . − Despite this fact, As and Sb analogs of 1 have been identified in matrix isolation infrared spectroscopic studies, and the molecular structures of CpM(CO) 3 [PC(SiMe 3 ) 2 ] 2f (M = Mo, W) and CpMo(CO) 3 {P(Cl)[( t Bu 3 C 6 H 2 O)]} 3e have been determined by single-crystal X-ray diffraction techniques. Structural determinations for examples of 2 are more abundant, and these compounds feature a trigonal planar phosphorus atom environment and a short, formal MP multiple bond. −

1

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“…The chemistry of 1 and 2 has been of interest in several groups. − Much of the reactivity of 1 derives from the nucleophilicity of the uncommitted phosphorus lone pair, and additions of H 3 B·THF, Ni(CO) 4 , and CH 3 I to CpW(CO) 2 (Me 3 P)(PPh 2 ), for example, result in formation of adducts CpW(CO) 2 (Me 3 P)[P(A)(Ph) 2 ] (A = H 3 B, (CO) 3 Ni, and CH 3 + ) 2d. Oxidations with S 8 and Br 2 also occur at the electron-rich PPh 2 center.…”