TITLE:
A Quantum Chemical Screening of Two Imidazole-Chalcone Hybrid Ligands and Their Pd, Pt and Zn Complexes for Charge Transport and Nonlinear Optical (NLO) Properties: A DFT Study
AUTHORS:
Fritzgerald Kogge Bine, Numbonui Stanley Tasheh, Julius Numbonui Ghogomu
KEYWORDS:
Density Functional Theory, Time-Dependent Density Functional Theory, Chalcone-Imidazoles, Charge Transport and Nonlinear Optical Properties
JOURNAL NAME:
Computational Chemistry,
Vol.9 No.4,
October
19,
2021
ABSTRACT: A
quantum chemical screening of two imidazole-based chalcone ligands: 2- [1-(3-(1H-imidazol-1-yl)propylimino)-3-(phenylallyl)]phenol and 2-[1-(3-(1H- imidazol-1-yl)propylimino)-3-4-nitrophenylallyl]phenol
(hereinafter referred to as HL1 and HL2 respectively) and their Pd,
Pt and Zn chelates for charge transport and nonlinear optical (NLO) properties,
is reported via dispersion- corrected density functional theory (DFT-D3) and time-dependent DFT (TD- DFT)
methods. From our results, Pd and Pt complexes have been observed to show
excellent hole-transport properties, owing to their very small reorganization energies. The light extraction efficiency of the HL1-Pt complex was deduced
to be particularly impressive, thus suitable for the manufacture of hole transport layer in violet light
emitting diodes (LEDs). Moreover, redox potentials and chemical stability
studies have enabled us to validate the greater stability in
moisture (towards oxidation), of HL2 complexes compared to their HL1
counterparts. The first and second hyperpolarizabilities of both ligands and
their complexes have been found to be outstandingly higher than those of the
push-pull prototypical, para-nitroaniline
by factors of up to 12 in the case of HL2. These compounds, with the exception
of the HL2-Pt complex, are thus interesting candidates having wide transparency
tradeoffs for NLO efficiency in the manufacture of optoelectronic and photonic
devices capable of second and third-order NLO response. Finally, metal
chelation has been established to enhance the NLO response of all the
chalcone-based imidazole ligands investigated as a result of metal-ligand
charge transfer and ligand- metal charge transfer electronic transitions identified in the resulting
complexes with the exception of the zinc complexes.