Electronic Spectra (Experimental and Simulated), and DFT Investigation of NLO, FMO, NBO, and MESP Characteristics of Some Biphenylcarboxaldehydes

Abstract

Experimental UV–Visible spectral data for biphenyl-4-carboxaldehyde (B4A), biphenyl-3-carboxaldehyde (B3A), and biphenyl-2-carboxaldehyde (B2A) were obtained in the spectral space 200–400 nm in a solution of CDCl_3. In order to substantiate the experimental data, theoretical quantum chemical calculations were made using time-dependent DFT (TD-DFT) formalism employing B3LYP functional in combination with 6–311++G(d,p) for the three molecules in CDCl₃ solution phase. Certain global reactivity descriptors were evaluated with the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) (FMOs) analysis, with in the frame work of DFT/B3LYP/6–311++G(d,p) method for the three molecules being investigated. The non-linear optical (NLO) material profiles of the three molecules consisting of their static NLO parameters were theoretically investigated to find their utility for NLO applications. Hyperconjugative interactions, as revealed by natural bond orbital (NBO) analysis, helped to explain NLO behavior of the molecules in terms of intramolecular charge transfer (ICT). The reactive sites of B4A, B3A, and B2A molecules were probed by MESP surface analysis.

Graphical Abstract

HIGHLIGHTS

• Experimental and simulated electronic absorption maxima agree well for, B4A, B3A, and B2A.

• Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) orbitals are used to understand π→π* UV–Visible transitions in the three molecules.

• The molecules are highly reactive and stable.

• B4A and B3A are good for developing NLO materials.

• Space around oxygen atom of the aldehyde moiety of the molecules is the most favorable site, for electrophilic attack.

Keywords:

• Biphenylcarboxaldehyde
• electronic spectra
• NLO
• FMO
• NBO
• MESP
• DFT

Acknowledgments

The authors sincerely acknowledge financial support, under SAP-DRS-II, extended by the University Grants Commission, New Delhi, India through their Lr.No.F.530/24/DRS-II, 2015 (SAP). They are also grateful to NIPER, Hyderabad for recording UV–Visible spectra. The first author (KSS) is grateful to the management of SR University, Warangal, India, for permitting him to undertake the reported investigations.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported under SAP-DRS-II, extended by the University Grants Commission, New Delhi, India through their Lr.No.F.530/24/DRS-II, 2015 (SAP).