The supramolecular assembly of tetraaqua-(pyridine-2,5-dicarboxylato)-copper(II) complex: crystal structure, TD-DFT approach, electronic spectra, and photoluminescence study

Abstract

The copper(II) complex, {[Cu(2,5-pdc)(H₂O)₄]·H₂O} (1) [2,5-pdc = pyridine-2,5-dicarboxylate], has been synthesized and characterized by elemental analysis, IR spectroscopy, and X-ray crystallography. The metal shows a distorted octahedral coordination sphere and in solid state the complex forms a 3-D supramolecular network via hydrogen bonding and off-center anti-parallel π–π stacking interactions between py rings. At room temperature, 1 exhibits fluorescence in methanolic solution [λ_ex = 226 nm, λ_em = 309, 330, and 341 nm]. The geometry optimization at the B3LYP/LanL2DZ level led to a five-coordinate copper having a distorted square pyramidal geometry. The electronic spectrum of this compound is compared with the results obtained by employing density functional theory (DFT) and time dependent density functional theory calculations.

Graphical Abstract

Keywords:

• Copper complex
• Pyridine-2,5-dicarboxylate
• Supramolecular assembly
• DFT analysis

Acknowledgements

Dr Subal Chandra Manna acknowledges CSIR, Government of India [CSIR Project No. 01 (2743)/13/EMR-II)] for financial support.