Structural Insights and Third Order NLO Studies of Pseudohalide‐ Based Polymeric and Monomeric Congeners of Halo‐Substituted Parent Schiff Bases

Abstract

AbstractThe present work focuses on the pseudohalide embodied copper(II) complexes of a tridentate Schiff base (HL) derived from N,N‐dimethylethylenediamine and 3,5‐dichloro‐2‐hydroxyacetophenone. Of them, two are coordination polymers and rest are monomers. The azide in the complex [Cu(L)(N3)]n, adopts an end‐on coordination mode begetting a trans helical propagation while the end‐to‐end bonding fashion of the dicyanamide in [Cu(L)[N(CN)2]n, fostered a meso‐helical chain. The interplay of covalent & non‐covalent forces develop the complexes into supramolecular architectures. Similar forces stitch the monomeric cyanato and thiocyanato complexes to chains. Quantification of intermolecular forces was achieved by surface analysis along with fingerprint plots. Charge‐transfer bands exhibit negative solvatochromic effect while the influence of the solvents on the geometry of the complexes is based on d‐d bands. Further, fluorescence and thermal studies were also done. The third order non‐linear optical (NLO) response of the complexes were recorded. Open aperture scan showed a positive NLO absorption coefficient and closed scan, a negative non‐linear refractive effect. A predominant refractive effect of the complexes make them ideal for optical switching applications.