Structure, characterisation and dynamics of copper(I) complexes of 2,6-bis(3,5-dimethylpyrazol-1-ylmethyl)pyridine

Two mononuclear copper(I) complexes of a tripodal ligand, 2,6-bis(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L), have been prepared, [CuL(ClO4)]·CH2Cl2 1 and [CuL(PPh3)]ClO4 2. A new route to L is also proposed. The crystal structures of both complexes have been determined. In 1 the perchlorate is bonded through one of its oxygens with a distance of 2.426(3) Å. In 2 the perchlorate ion is thermally disordered. A variable-temperature NMR study of both complexes revealed that the methylene carbon of 2 is chiral at low temperatures. Carbon monoxide formed a terminal adduct with 1.