Divalent molybdenum complexes of the dipyrrolide ligand system.: Isolation of a Mo2 unit with a 45° twist angle

The preparation of divalent(.)Mo'complexes of dipyrrolide dianions was carried out by reacting Mo-2(acetate)4 with the dipotassium salts of Ph2C(2-C4H3NH)(2) and 2-[1,1-bis(1H-pyrrol-2-yl)ethyl]pyridine. The two reactions respectively afforded the diamagnetic {[Ph2C(C4H3N)(2)](2)Mo-2(OAc)(2)[K(THF)(3)][K(THF)]}(THF)-T-. (1) and {[(2-C5H4 N)(CH3)C(2-C4H3N)(2)]-Mo(OAc)[K(THF)]}(2)(THF)-T-. (2). Both compounds retained two acetate units in the dimetallic structure. Conversely, the reaction of Me8Mo2Li4(THF)(4) with Et2C(2-C4H3NH)(2) afforded the paramagnetic dimer {[Et2C(C4H3N)(2)](4)Mo2Li2}- {Li(THF)(4)}(2)(.)0.5THF (3). The paramagnetism is most likely caused by the 45degrees rotation of the two Mo(dipyrrolide) units with respect to each other and which, in turn, is caused by the presence of two lithium cations in the molecular structure.