Theoretical investigations on electronic structure and optoelectronic properties of vinyl fused monomeric and oligomeric benzimidazole derivatives using DFT and TDDFT techniques

Reshad Bushra Ahmed; Boobalan Maria Susai; Kishore Kumar Sadasivuni; G Neelaiah Babu; Jone Pradeepa Susairaj; R Ramamoorthy; L Muruganandam

doi:10.1007/s00894-024-05830-6

Theoretical investigations on electronic structure and optoelectronic properties of vinyl fused monomeric and oligomeric benzimidazole derivatives using DFT and TDDFT techniques

J Mol Model. 2024 Jan 16;30(2):40. doi: 10.1007/s00894-024-05830-6.

Authors

Reshad Bushra Ahmed¹, Boobalan Maria Susai^{2

3}, Kishore Kumar Sadasivuni^{4

5}, G Neelaiah Babu¹, Jone Pradeepa Susairaj^{6

7}, R Ramamoorthy⁸, L Muruganandam⁹

Affiliations

¹ Department of Chemistry, College of Natural and Computational Sciences, Haramaya University, Dire Dawa, Ethiopia.
² Department of Chemistry, College of Natural and Computational Sciences, Haramaya University, Dire Dawa, Ethiopia. jerry.fedrick@gmail.com.
³ Cambridge International School, P.O. Box 23018, Doha, Al Nuaija East, Qatar. jerry.fedrick@gmail.com.
⁴ Centre for Advanced Materials, Qatar University, Doha, Qatar.
⁵ Department of Mechanical and Industrial Engineering, Qatar University, PO Box 2713, Doha, Qatar.
⁶ Department of Physics, Annamalai University, Chidambaram, Tamil Nadu, 608 002, India.
⁷ Doha Modern Indian School, P.O. Box 47391, Doha, Abu Hamour, Qatar.
⁸ Department of Physics, Arulmigu Palaniandavar College of Arts and Culture, Palani, Dindigul, Tamil Nadu, 624 601, India.
⁹ Department of Chemistry, Saranathan College of Engineering, Tiruchirappalli, Tamil Nadu, 620012, India.

PMID: 38227112
DOI: 10.1007/s00894-024-05830-6

Abstract

Context: The present work encompasses the theoretical investigation of 14 benzimidazole-based (seven vinyl fused monomeric benzimidazole (VFMBI) and seven vinyl fused oligomeric benzimidazole (VFOBI)) derivatives using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) techniques. The effects of electron donor and acceptor groups on the electronic structure such as HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies, HOMO-LUMO energy gap, ionization potentials (IPs), electron affinities (EAs), internal reorganization energies of holes and electrons (λ_h/e), and excited state properties have been explored in the present work. In addition, natural bond orbital (NBO) analysis of these compounds has been investigated to reveal the typical stabilization interactions in these molecules. Hence, the aim of the present work is to explore the electronic structures and optoelectronic properties of the title molecules on the basis of the DFT quantum chemical calculations and to make an idea on the parameters influencing the optoelectronic efficiency toward a better understanding of the structure-property relationships. Moreover, the calculated results reveal the suitable optoelectronic properties of benzimidazole oligomer derivatives using theoretical techniques. Of the investigated molecules, 4_MABIMCY and 4_MABIOCY show potential optoelectronic properties and can be used as a potential charge transport material due to their narrow band gap, high hyperpolarizability, low ionization potential, and high electron affinity. The larger λ_ab and λ_em values favor the system to be used as a potential optoelectronic material with better optical properties.

Methods: All quantum chemical calculations were carried out using Gaussian09 theoretical chemistry code. Ground state calculations were made using the B3LYP/6-31+G(d,p) method. All excited state calculations had been computed using TDB3P86/6-311++(d,p). The initial structure for excited state calculations was optimized using the AM1 semi-empirical method.

Keywords: Benzimidazole; DFT and TDDFT calculations; Monomer; Oligomer; Optoelectronic properties.