Density functional investigation of photo induced Intramolecular Proton Transfer (IPT) in Indole-7-carboxaldehyde and its experimental verification

作者：Singla Nidhi; Chowdhury Papia^*

来源：Journal of Molecular Structure, 2013, 1045: 72-80.

DOI：10.1016/j.molstruc.2013.04.015

• Intramolecular hydrogen bonding (IHB)
• ESIPT
• Atoms in molecule (AIM)
• Mulliken
• Natural bond orbitals (NBOs)
• Zwitterion

A detail theoretical study has been performed using Density functional theory (DFT) and Time dependent DFT (TDDFT) to investigate the Intramolecular Proton Transfer (IPT) mechanism in Indole-7-carboxaldehyde (I7C) from its normal (I*) to zwitterion (II*) form. B3LYP/6-311++G (d, p) basis set has been used to obtain structural parameters and relative energies in the ground state (S-0) and excited state (S-1). Atoms in Molecules (AIMs), Mulliken and Natural bond orbitals (NBOs) analysis proves the existence of intramolecular hydrogen bonding (IHB). The electron density (rho) at Bond critical points (BCPs) on a hydrogen bridge (N-15-H-12 center dot center dot center dot O-18) certify IHB and possibility of IPT from acidic (N-15-H-12) to basic ((sic)C-16=O-18) group and creation of II*. Transition state (TS) with dual minima in the Potential energy surface (PES) confirms the I*-> TS -> II* transition due to excited state Intramolecular Proton Transfer (ESIPT). Photo-physical pathway from I*-> II* agrees well with computed/experimental emission peaks.

• 出版日期2013-8-6