A comprehensive investigation of structural features, electron delocalization, optoelectronic and anti-corrosion characteristics in furan oligomers by DFT/TDDFT method

Abstract

The furan oligomer with 1π-bridge to 5π-bridge has been appraised for optoelectronic properties, using Density Functional Theory and Time Dependent Density Functional Theory (DFT/TDDFT) methods. Frontier Molecular Orbital analysis aids in band gap calculation of furan oligomers and limelight the Highest Occupied Molecular Orbitals (HOMOs) lobes localized on π-bridge and donor & LUMOs are localized on π-bridge and acceptor moiety. Values of common aromaticity indices include Harmonic Oscillator Model of Aromaticity (HOMA) and Bird’s (Aromaticity Index) AI for electronic delocalization indicates high magnitude of aromaticity at acceptor end in furan oligomers, and also the magnitude increases with the increase in the number of π-bridges. The hyperpolarizability (β◦) values show many-fold degree of enhancement in its magnitude by the addition of π-bridge. The absorption maxima of furan oligomers in gas and Dichloromethane medium (DCM) are calculated through TDDFT calculations. Polarizable continuum model (PCM) analysis demonstrates that furan oligomer shows positive solvatochromism. Natural Bond Orbital analysis helps to sustain the evidence for delocalization in these systems. Overall the furan oligomer with more π-bridge shows, an enhanced aromaticity through electronic delocalization which is very helpful to enhance optoelectronic property and anti-corrosion ability.