TY - JOUR
T1 - The excited state dipole moments of betaine pyridinium investigated by an innovative solvatochromic analysis and TDDFT calculations
AU - Pawlowska, Zuzanna
AU - Lietard, Aude
AU - Aloïse, Stéphane
AU - Sliwa, Michel
AU - Idrissi, Abdenacer
AU - Poizat, Olivier
AU - Buntinx, Guy
AU - Delbaere, Stéphanie
AU - Perrier, Aurélie
AU - Maurel, François
AU - Jacques, Patrice
AU - Abe, Jiro
PY - 2011/1/1
Y1 - 2011/1/1
N2 - This work reports on the solvatochromic properties of a simple heterocyclic betaine pyridinium, 2-(1-pyridinio)benzimidazolate (SBPa), having promising potentialities in non-linear optics. From advanced PCM-TDDFT calculations, the solvatochromism of SBPa was found to be unusual, involving two different electronic states for absorption (S0→ S2) and emission (S1→S′0). To account for this behavior, we developed an innovative physical treatment which consists in a non-linear fit of the solvatochromic data using the Bilot-Kawski theoretical model and visualizing the least-square coefficient χ2 on a 2D map as a function of the solute polarizability and gas phase absorption energy. In parallel, Kamlet-Taft correlations were undertaken to select a propitious set of electrostatic solvents usable in this treatment. Protic solvents that lead to specific interactions and nonpolar solvents that favor dimerization processes were excluded. From a choice of aprotic solvents with sufficiently high polarity, 4 dipole moments µg(S0) = +9.1 D, µe(S2) = -1.5 D, µe(S1) = 0 D and µg(S′0) = +3.31 D were determined, the 3 former values being in close agreement with TDDFT values, although the solute polarizability values seem underestimated. Anyhow, disregarding this discrepancy, we evaluated the static hyperpolarizability to β(0) = -64 × 10-30 esu from the solvatochromic data in close agreement with DFT calculations.
AB - This work reports on the solvatochromic properties of a simple heterocyclic betaine pyridinium, 2-(1-pyridinio)benzimidazolate (SBPa), having promising potentialities in non-linear optics. From advanced PCM-TDDFT calculations, the solvatochromism of SBPa was found to be unusual, involving two different electronic states for absorption (S0→ S2) and emission (S1→S′0). To account for this behavior, we developed an innovative physical treatment which consists in a non-linear fit of the solvatochromic data using the Bilot-Kawski theoretical model and visualizing the least-square coefficient χ2 on a 2D map as a function of the solute polarizability and gas phase absorption energy. In parallel, Kamlet-Taft correlations were undertaken to select a propitious set of electrostatic solvents usable in this treatment. Protic solvents that lead to specific interactions and nonpolar solvents that favor dimerization processes were excluded. From a choice of aprotic solvents with sufficiently high polarity, 4 dipole moments µg(S0) = +9.1 D, µe(S2) = -1.5 D, µe(S1) = 0 D and µg(S′0) = +3.31 D were determined, the 3 former values being in close agreement with TDDFT values, although the solute polarizability values seem underestimated. Anyhow, disregarding this discrepancy, we evaluated the static hyperpolarizability to β(0) = -64 × 10-30 esu from the solvatochromic data in close agreement with DFT calculations.
U2 - 10.1039/c1cp20920e
DO - 10.1039/c1cp20920e
M3 - Article
AN - SCOPUS:79960373981
SN - 1463-9076
VL - 13
SP - 13185
EP - 13195
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 29
ER -