Synthesis and structural characterization of heteroleptic Cu(I) complexes with α-diimines derived from pyridinyliminobenzoic acids

Abstract

The synthesis and molecular and electronic structure of heteroleptic univalent copper compounds [Cu(L)(PPh₃)X] are reported where X is a halide and L represents 3-pyridinylimino, 4-pyridinylimino or 3,5-dipyridinylimino-substituted benzoic acid, hereafter abbreviated as L1, L2, and L3, respectively. The crystal structures of two iodide and one bromide complexes are described. All compounds are hydrogen-bonded dimers. The electronic excitation spectra of the compounds are dominated by intraligand bands of ligands while characteristic MLCT transitions are observed at 430–480 nm. No emission is observed from the compounds either in the solid state or in solution; on the contrary a photodecomposition is observed resulting in triphenylphosphane ligand elimination and formation of halogen-bridged dimmers.

Keywords:

• Copper(I)
• α-Diimine
• Triphenylphosphine
• Crystal structure
• Spectroscopic study