Homoleptic versus heteroleptic Zn(II) complexes: from noncovalent interactions to photosensitive Schottky barrier diodes

We report syntheses, structural characterization, theoretical aspects and photophysical properties of three Zn(II) complexes using either terpyridine (tpy) or chelidamic acid (H 2 cda) ligand or both: [Zn(tpy)(cda)]·3H 2 O ( 1 ), [Zn(tpy) 2 ]2NO 3 ·2H 2 O ( 2 ), and [Zn(cda)(H 2 O)] n ·nH 2 O ( 3 ). Single-crystal X-ray diffraction reveals diverse supramolecular architectures stabilized by π⋯π, anion⋯π, classical O H⋯O as well as non-classical C H⋯O hydrogen bonding interactions in the three title Complexes ( 1–3 ). Furthermore, Hirshfeld surface analysis and fingerprint plots were employed to demonstrate the quantitative comparisons on hydrogen bonding interactions among three complexes ( 1–3 ). DFT-based MEP, QTAIM and NCI-plot analyses quantify the noncovalent interactions in complexes 1 and 2 , revealing dimerization energies of up to −17.0 kcal/mol dominated by π⋯π stacking, with C–H⋯O contacts contributing −2.6 to −5.1 kcal/mol, and anion⋯π interactions of −20.6 kcal/mol in complex 2 . Finally, these complexes were found to have potential application as optoelectronic devices. The nonlinear rectifying ‘I’–‘V’ characteristics exhibited by device 1 (Complex 1 ), together with its corresponding device parameters, suggest better performance compared to devices 2 and 3 (Complexes 2 and 3 ), indicating its potential for application in optoelectronic device fabrication. This phenomenon has also been supplemented by solid-state density functional theory (DFT) calculations. Henceforth, our present work amalgamated supramolecular, photophysical, and theoretical studies of Zn(II) metal complexes in a single frame.