Liquid-assisted mechanochemical synthesis, crystallographic, Hirshfeld surface and theoretical study for Nonlinear Optical (NLO) properties of novel copper complexes: Bis(2,9-dimethyl-1,10-phenanthroline)-copper perchlorate and bromidobis(1,10-phenanthroline)-copper

Abstract

The two novel Cu (I) complexes, [Cu(dmp)2]ClO4 with 2,9-dimethylphenanthroline (dmp) and [Cu(phen)2Br] with 1,10-phenanthroline (phen) were synthesized by liquid assisted grinding (LAG) method followed by heating. Complexes were characterized by using SC-XRD, FT-IR and UV-Visible spectroscopic techniques. The complex (1) [Cu(dmp)2]ClO4 crystallized in the Orthorhombic with the space group P 21 21 21, a = 11.9229(2) Å, b = 12.4823(3) Å, c = 18.2499(3) Å and Complex (2) [Cu(phen)2Br] crystallized in the Monoclinic with the space group C2/c, a = 23.247(5) Å, b = 30.731 (6) Å, c = 7.5317(15) Å and β = 97.677(6)o. The FMOs study based on DFT showed the complex (2) has high value of chemical softness and more easily polarized compare to complex (1). The HOMO-LUMO energy gap in complex (2) is small compared to complex (1) due to which there is easier intramolecular charge transfer (ICT) in complex (2) which support the higher third order NLO (γ) response of the complex (2). The statistical calculations for Pearson correlation coefficient (r) and the P values showed that the selected level of theory is appropriate for the theoretical calculations of the complexes. Theoretical calculation showed that both the complexes have higher third order NLO response compared to prototypical urea.