Structural diversity, spectral characterization and computational studies of Cu(I) complexes with pyridylamide ligands

•Five Cu(I) complexes with pyridylamide ligands were synthesized.•Solid structures were determined by single crystal X-ray crystallography.•Spectroscopic and electrochemical characterization showed interesting properties.•Computational studies revealed the detailed electronic structure of the complex involving Cu(I)⋯Cu(I) interaction.

Cu(I) complexes supported by pyridylamide ligands N-2-acetamidopyridine (Haap), N-(3-pyridyl)nicotinamide (3-pna), N-(2-pyridyl)isonicotinamide (2-pina) and N-(4-pyridyl)picolinamide (4-ppa) were synthesized and characterized. The reaction of CuCl with the deprotonated form of Haap yielded the complex [Cu2(aap)2]n (1) with a one-dimensional polymeric structure. Complexes [Cu(3-pna)3(NCCH3)](HF)(SbF6) (2) and [Cu(4-ppa)(NCCH3)2]BF4 (5) displayed mononuclear structures with tetrahedral geometries on Cu(I) centers. Dinuclear complex [Cu2(2-pina)3(NCCH3)4](SbF6)2 (3) and tetranuclear cluster [Cu4(2-pina)4(NCCH3)4](SbF6)4 (4) were afforded from the same reaction in CH3CN and DMF, respectively. Detailed analysis of X-ray crystal structures and Hirshfeld surface maps suggested that the weak non-covalent interactions and reaction solvents imposed a collaborative effect on the structural conformations of the Cu(I) complexes. The electrochemical properties of the complexes were investigated by cyclic voltammetry. Computational studies focusing on complex 1 revealed its unique electronic structure that corresponds to the interesting spectroscopic and electrochemical properties.

Graphical abstractSynthesis and characterization of five Cu(I) complexes supported by pyridylamide ligands is reported. The complexes exhibited interesting structural features, and Hirshfeld surface analysis based on X-ray crystal structures identified the weak interactions among the coordination units. UV–Vis and cyclic voltammetry characterization of the complexes were interpreted based on computational studies.Figure optionsDownload full-size imageDownload as PowerPoint slide