Structural variation in copper(<scp>i</scp>) complexes with pyridylmethylamide ligands: structural analysis with a new four-coordinate geometry index, τ₄

Abstract

Four Cu(I) complexes were synthesized with a family of pyridylmethylamide ligands, HL(R) [HL(R) = N-(2-pyridylmethyl)acetamide, R = null; 2,2-dimethyl-N-(2-pyridylmethyl)propionamide, R = Me(3); 2,2,2-triphenyl-N-(2-pyridylmethyl)acetamide, R = Ph(3))]. Complexes 1-3 were synthesized from the respective ligand and [Cu(CH(3)CN)(4)]PF(6) in a 2 : 1 molar ratio: [Cu(HL)(2)]PF(6) (1), [Cu(2)(HL(Me3))(4)](PF(6))(2) (2), [Cu(HL(Ph3))(2)]PF(6) (3). Complex 4, [Cu(HL)(CH(3)CN)(PPh(3))]PF(6), was synthesized from the reaction of HL with [Cu(CH(3)CN)(4)]PF(6) and PPh(3) in a 1 : 1 : 1 molar ratio. X-Ray crystal structures reveal that complexes 1, 3 and 4 are mononuclear Cu(I) species, while complex 2 is a Cu(I) dimer. The copper ions are four-coordinate with geometries ranging from distorted tetrahe