Synthesis of the [MeAl(2-py)₃]^- anion and its application as a stable and mild pyridyl-transfer reagent (2-py = 2-pyridyl)

The thermally stable tris(pyridyl) Al(III) complex [MeAl(2-py) ₃Li-THF] (1-THF), obtained from the reaction of lithiopyridine [2-pyLi] with MeAlCl₂ (3:1 molar equiv, respectively), functions as a pyridyl-transfer reagent, as exemplified by the reaction of 1-THF with CuCl (1:1 molar equiv), which gives the Cu(I) organometallic [{Cu(2-py)} ₃]_∞ (2). The solid-state structures of 1, the dimer [MeAl(2-py)₃Li]₂ ([1]₂), and 2 are reported. Complex 2, which cannot be obtained by direct reaction of [2-pyLi] with CuCl, has a polymeric structure in which macrocyclic [Cu(2-py)]₃ ring units form infinite offset stacks associated by short Cu⋯Cu interactions between three- and four-coordinate Cu(I) centers (2.762(3) Å).