title: Comprehensive DFT and TD-DFT Studies on the Photophysical Properties of 5,6-Dichloro-1,3-Bis(2-Pyridylimino)-4,7-Dihydroxyisoindole: A New Class of ESIPT Fluorophore.
abstract: Hanson et al. [Org. Lett., 2011] reported the absorption and emission spectrum of 5,6-dichloro-1,3-bis(2-pyridylimino)-4,7-dihydroxyisoindole but the excited-state intramolecular proton transfer (ESIPT) process was not investigated. The photo-physical behaviour of 5,6-dichloro-1,3-bis(2-pyridylimino)-4,7-dihydroxyisoindole was studied using the density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The functional used was B3LYP and 6-31G(d) was the basis set for all the atoms. All the ten tautomers were studied for the absorption and emission properties. It is found that the tautomer where hydroxyl groups are syn to nitrogen of isoindoline ring is most stable and thus, responsible for the ESIPT process. The computed absorption and emission values of tautomers using TD-DFT are in good agreement with those obtained experimentally.
authors.affiliation: Tinctorial Chemistry Group, Department of Dyestuff Technology, Institute of Chemical Technology, N. P. Marg, Matunga, Mumbai, MH, 400019, India.
authors.forename: Santosh
authors.initials: S
authors.lastname: Kataria
authors.affiliation: Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 80837, Mauritius.
authors.forename: Lydia
authors.initials: L
authors.lastname: Rhyman
authors.affiliation: Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 80837, Mauritius. p.ramasami@uom.ac.mu.|Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box. 2457, Riyadh, 11451, Kingdom of Saudi Arabia. p.ramasami@uom.ac.mu.|Department of Chemistry, College of Science, Engineering and Technology, University of South Africa, P.O. Box 392, Pretoria, 0003, South Africa. p.ramasami@uom.ac.mu.
authors.forename: Ponnadurai
authors.initials: P
authors.lastname: Ramasami
authors.affiliation: Tinctorial Chemistry Group, Department of Dyestuff Technology, Institute of Chemical Technology, N. P. Marg, Matunga, Mumbai, MH, 400019, India. n.sekar@ictmumbai.edu.in.
authors.forename: Nagaiyan
authors.initials: N
authors.lastname: Sekar
keywords: 1,3-bis(2-pyridylimino) isoindoline (BPI); DFT; ESIPT; TD-DFT