Copper(I) coordination chemistry of (pyridylmethyl)amide ligands

Copper(I) chloro complexes were synthesized with a family of ligands, HLR [HLR = N-(2-pyridylmethyl)acetamide, R = null; 2-phenyl-N-(2-pyridylmethyl) acetamide, R = Ph; 2,2-dimethyl-N-(2-pyridylmethyl) propionamide, R = Me-3; 2,2,2-triphenyl-N-(2-pyridylmethyl) acetamide, R = Ph-3)]. Five complexes were synthesized from the respective ligand and cuprous chloride: [Cu(HL)Cl](n) (1), [Cu-2(HL)(4)Cl-2] (2), [Cu-2(HLPh)(2)(CH3CN)(2)Cl-2] (3), [Cu-2(HLPh3)(2)Cl-2] (4), and [Cu(HLMe3)(2)Cl] (5). X-ray crystal structures reveal that for all complexes the ligands coordinate to the Cu in a monodentate fashion, and inter- or intramolecular hydrogen-bonding interactions formed between the amide NH group and either amide C=O or chloro groups stabilize these complexes in the solid state and strongly influence the structures formed. Complexes 1-5 display a range of structural motifs, depending on the size of the ligand substituent groups, hydrogen bonding, and the stoichiometry of the starting materials, including a one-dimensional coordination polymer chain (1) and binuclear (2-4) or mononuclear (5) structures.