Mo2(OCH2tBu)6(Cp)Na(DME). Preparation, structure, and solution behavior

From the reaction between Mo2(OCH2tBu)6 and NaCp (Cp = C5H5) in THF the title complex was obtained as a crystalline product in the presence of DME (DME = dimethoxyethane). Crystal data for Mo2(OCH2tBu)6(Cp)Na(DME) at −167 °C: a = 11.885(2) A, b = 19.240(1) A, c = 11.562(2) A, α = 102.73(1)°, β = 106.95(1)°, γ = 98.55(1)°, Z = 2 and space group of . In the solid state there is an unbridged Mo≡Mo bond of distance 2.276(1) A. One Mo atom is bonded to four alkoxides, two of which are also bonded to Na+ while the other is η5-bonded to the Cp ligand, with Mo—C distances ranging from 2.34 to 2.66 A, and to two OR groups, one of which is bound to the Na+ ion. In addition to the coordination to three OR groups the Na+ ion binds one DME molecule via both of its ether oxygen atoms. The Mo—O distances fall in the range 1.91–2.01 A with the longer distances being associated with those groups that are also bonded to the Na+ ion. In polar solvents the title complex dissociates to give Mo2(OCH2tBu)6 and Na+ Cp−. Key word...