Bis- and Tetrakis carboxylato dimolybdenum II Complexes

Mo2X4[P(m-C4H9)3] 4 + 2ArC02H - Mo2X2(02CAr)2[P( -C4H9)3] 2 

Tetrakis-/i-(carboxylato)-dimolybdenum(II) complexes have been obtained by only one general route, namely by the direct interaction of carboxylic acids with molybdenum hexacarbonyl.8 This reaction requires elevated reaction temperatures and prolonged reaction times. These same compounds are obtained in comparable or better yields by the brief reaction of tetrachloro- or tetrabromotetrakis(tributylphosphine)dimolybdenum(II) with alkyl- or aryl-carboxylic acids in refluxing benzene. The bis-/i-(arylcarboxylato) complexes 

Tetrakis-q-(butyrato)-dimolybdenum(II) is a bright-yellow complex that is soluble in a spectrum of organic solvents, including THF and benzene (but not petroleum ether). It is very air sensitive in both the solid state and in solution and must be handled under an inert atmosphere at all times. It can be stored under nitrogen indefinitely. 

Dibromobis-/i-(benzoato)-bis(tributylphosphine)-dimolybdenum(lI) is a bright orange-red compound. It is soluble in a broad spectrum of organic solvents 

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