Synthesis, structure, and electronic study of some group VII furoyl substituted complexes

The reaction of fulvene 1 with TlOEt in THF affords [Tl{1,2-C5H3(COC4H3O)2}] (2) in 60% yield. Treatment of 2 with [MBr(CO)5] (M = Mn, Re) in benzene reflux gave [Mn{η5-1,2-C5H3(COC4H3O)2}(CO)3] (3A) and [Re{η5-1,2-C5H3(COC4H3O)2}(CO)3] (3B) in 61% and 66% yields, respectively. Diacyl complexes 3A and 3B were ring-closed to the pyridazine by treating with hydrazine hydrate in methanol at room temperature. Fulvene 1 and diacyl complexes 3A and 3B have been structurally characterized by X-ray crystallography. Additionally, the electronic structure of complexes 3A and 3B and their relaxed structures have been characterized with density functional calculations. Calculated vibrational frequencies are compared with the experimental characterizations.