Pentacarbonyl diphenylmethylene tungsten

Both W(CO)5[C(C6Hs)2] and the analogous di-p-tolylmethylene complex have been used in model studies of the olefin metathesis reaction.2 3 In contrast to heteroatom-stabilized carbene complexes such as W(CO)s [C(OCH3)(C6Hs)], pentacarbonyl(diphenylmethylene)tungsten(0) reacts with alkenes to give cyclopropanes and 1,1-diphenylalkenes.2 The compound W(CO)5 [C(C6H5)2] is the best reported catalyst for the metathetical polymerization of 1-methylcyclo-butene.4... 

Pentacarbonyl(diphenylmethylene)tungsten(0) is a moderately air-stable soild that is readily soluble in most organic solvents. The resulting solutions are air and light sensitive and decomposed thermally at about 50°. The infrared spectrum of a heptane solution shows bands in the metal carbonyl region at 2070 (m), 1971 (s), and 1963 (s) cm"1, characteristic of a group VI pentacar-bonyl species. The proton NMR spectrum in CS2 or acetone-d6 shows a complex multiplet at 5 7.2 relative to internal tetramethylsilane. 

Diphenyl telluroketone was generated, when pentacarbonyl(diphenylmethylene)tungsten reacted with bis[triphenylphosphine]iminium tellurocyanate3. The telluroketone remained coordinated to the tungsten. 

Pentacarbonyl(diphenyl telluroketone)tungsten(II)3 Under dry nitrogen solutions of 980 mg (2 mmol) of pentacarbonyl(diphenylmethylene)tungsten in 20 ml of dichloromethane and of 1.38 g (2 mmol) of bis[triphenylphosphine]iminium tellurocyanate in 10 ml of dichloromethane, both at — 90°, are combined and stirred for 10 min at that temperature- The mixture is then chromatographed on silica gel at — 50° with pentane/dichloromethane (10 1 v/v) as the mobile phase. The blue fractions are collected, the solvent is distilled under high vacuum, and the residue is recrystallized from pentane, yield 220 mg (18%) m.p. 35° (dec.). 

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