A TDDFT Study of the Fluorescence Properties of Three Alkoxypyridylindolizine Derivatives

Abstract

The fluorescence properties of three pyridylindolizine derivatives (one tricarbomethoxy-7-pyridyl-pyrrolopyridine and two dicarboethoxy-3-bromobenzoyl-7-pyridyl-pyrrolopyridines) have been investigated by applying density functional theory (DFT) and the time-dependent DFT (TDDFT). Performances of two hybrid-type functionals (BH&HLYP and B3LYP) and one generalized gradient approximation (GGA) functional (PBE) as well as three basis sets (SV(P), DZP, and TZVP) have been assessed. The solvent environment has been modeled with the conductor-like screening model (COSMO). Of the three functionals only BH&HLYP is able to yield reasonable estimates for all the studied indolizine derivatives whereas the success of the PBE and B3LYP functionals is highly dependent on the structure of the studied molecule. The SV(P) basis set provides geometrical changes as well as fluorescence maxima and Stokes shifts that agree with those obtained with DZP and TZVP. When a nonpolar solvent is used, COSMO is able to reproduce the experimental fluorescence maxima and Stokes shifts well. However, the agreement between the calculations and experiments is not as good when a solvent with higher polarity is used.

Electronic structure and spectroscopic properties of 6‐aminophenanthridine and its derivatives: Insights from density functional theory

“…However, to obtain the best agreement between the theoretically predicted and experimentally derived values, use of different functionals and basis sets can be important. Several examples supporting this notion can be found in literature …”

“…Several examples supporting this notion can be found in literature. [16,17] In this context, the present investigation includes:…”

Static quenching of tryptophan fluorescence in proteins by a dioxomolybdenum(VI) thiolate complex

“…The structures of tryptophan, the dioxo-Mo(VI) complex and various orientations of the complex were first optimized using Hartree-Fock theory and the LanL2DZ basis set. Excited states were modeled using the time-dependent self-consistent-field (TD-SCF) method following computational methodologies described in the literature [33][34][35]. Structures were first optimized in the gas-phase and then in water, where the Polarized Continuum Model (PCM) was used.…”

Nucleophilic Dearomatization of Activated Pyridines

“…When 1,3-dipolar cycloaddition of pyridinium ylides with electron-deficient olefins or alkynes is followed by oxidative aromatization (spontaneous or chemically induced) a convergent and straightforward access toward functionalized indolizines is arranged. Many excellent examples of this synthetic sequence (cycloaddition/aromatization) have been published (for examples see [75,[77][78][79][80][81][82]) as indolizine is an important skeletal structure present in many natural and synthetic bioactive molecules (for examples see [83][84][85][86][87][88][89][90][91][92][93]) and in material with photochemical properties [94][95][96][97][98][99][100][101][102]. Pivina and co-authors recently reported quantum chemical calculations on the spatial and electronic structure of pyridinium ylides, as well as the modelling of their1,3-dipolar cycloadddition reactions.…”