Carbon‐Rich Acetylide Bridged Binuclear Cu(I) Complexes: Electrochemical, Luminescent, and Nonlinear Optical Properties

ABSTRACT A new series of carbon‐rich alkynyl‐functionalized Schiff base ligands ( L 1–4 ) and their corresponding binuclear Cu(I) complexes of the type [Cu 2 ( L 1 / L 2 )( phen / bipy ) 2 ] ( 1a‐d ) and [Cu 2 ( L 3 / L 4 )( phen / bipy ) 2 ] ( 2a‐d ); incorporating diimine coligands phen = 1,10‐phenanthroline, bipy = 2,2′‐bipyridine were successfully synthesized and structurally characterized by elemental analysis, IR, 1 H NMR, UV–vis, PXRD, SEM, and mass spectrometry. The electrochemical behavior of the complexes reveals quasi‐reversible Cu(I)/Cu(II) redox couples, significantly influenced by ligand conjugation and electronic substituent effects. Photophysical investigations show that the complexes exhibit intense visible emission at room temperature, originating from mixed intra‐ligand and metal‐to‐ligand charge‐transfer excited states. Furthermore, second harmonic generation (SHG) measurements demonstrate notable nonlinear optical responses, highlighting the role of extended π‐conjugation in enhancing NLO activity. The combined electrochemical, luminescent, and nonlinear optical properties underline the potential relevance of these carbon‐rich Cu(I) systems for optoelectronic and photonic material applications.