Chemistry of dimolybdenum complexes containing anions of N,N′-di(6-methyl-2-pyridyl)formamidine (HDMepyF) and carboxylate ligands

Reactions of Mo2(O2CCF3)4 and Mo2(O2C(CH2)nCH3)4 with N,N′-di(6-methyl-2-pyridyl)formamidine (HDMepyF) in CH2Cl2 afforded complexes of the types Mo2(O2CCF3)2(DMepyF)2, 1, and Mo2(O2C(CH2)nCH3)2(DMepyF)2 (n=0, 2; n=2, 3; n=5, 4; n=8, 5; n=14, 6), respectively. Their structures have been determined by X-ray crystallography. The molecular structures of complexes 1–6 consist of two quadruply bonded molybdenum atoms, which are spanned by two trans bridging formamidinate ligands and two trans bridging carboxylate ligands. The formamidinate ligands are coordinated to the Mo centers in bidentate fashions via the two central nitrogen atoms and the two terminal pyridyl rings are dangling. The DMepyF− ligand adopts the s-cis, s-trans-conformation, resulting in a Mo⋯N and a Mo⋯HC short distances. Complex 6 is the first structurally characterized dimolybdenum complex containing carboxylate ligands with the longest alkyl chains.