Mononuclear photoluminescent salicylaldimato copper(II) complex: synthesis, characterization, mesomorphic investigation and DFT study

ABSTRACT

A new photoluminescent disc-like copper (II) metallomesogen of the type [CuL₂] {H₂L = 2,4-bis((E)-((4-(hexadecyloxy)phenyl)imino)methyl)phenol} have been synthesized. The compounds were characterized by elemental analyses, Fourier transform infrared spectroscopy (FTIR), ¹H, ¹³C nuclear magnetic resonance (NMR), ultraviolet – visible spectroscopy (UV – Vis), thermogravimetric analysis (TGA) and high-resolution mass spectrometry. Mesomorphic behavior of the compounds was probed with the help of polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The organization of the molecules in the mesophase was investigated by X-ray diffraction techniques. The ligand is non-mesogenic but the copper complex exhibited thermally stable columnar mesophases at about 86°C. The copper complex is a blue-light emitter both in solution and in the solid state. The Density Functional Theory (DFT) study was carried out using 6–31 G (d, p) basis set with unrestricted B3LYP level to obtain a stable, optimized structure, which revealed a distorted square-planar geometry for the copper complexes.

KEYWORDS:

• Mesomorphic
• photoluminescent
• Schiff base
• columnar
• DFT

Acknowledgments

Authors gratefully acknowledge financial support under UGC-SAP and DST-FIST program, New Delhi. HARP is thankful to the Council of Scientific and Industrial Research (CSIR), New Delhi, India for research fellowship (No.09/747(0006)/2011-EMR-I), BK is thankful to the Ministry of Tribal Affairs, New Delhi, India for NFST fellowship (No-201920-NFST-MEG-00512).

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/1539445X.2023.2232777.