A comprehensive study of the photophysical properties of a series of monoaza[5]helicenes is presented on the basis of joint optical spectroscopy and quantum chemistry investigations. The molecules have been characterized by absorption and CW/time-resolved luminescence measurements. All quantities related to spin-orbit-coupling processes; such as intersystem crossing rates and radiative phosphorescence lifetimes, were found to depend strongly on the nitrogen position within the carbon backbone. Density functional theory and semiempirical quantum-chemical methods were used to evaluate the molecular geometries, the characteristics of the excited singlet and triplet states, and the spin-orbit coupling matrix elements. We demonstrate that the magnitude of spin-orbit coupling is directly con-elated with the degree of deviation from planarity. The trends from the calculated photophysical quantities, namely, radiative fluorescence and phosphorescence decay rates and intersystem crossing rates, of the mono-aza-helicenes are fully consistent with experiment.

Schmidt, K., Brovelli, S., Coropceanu, V., Beljonne, D., Cornil, J., Bazzini, C., et al. (2007). Intersystem crossing processes in nonplanar aromatic heterocyclic molecules. JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY, 111(42), 10490-10499 [10.1021/jp075248q].

Intersystem crossing processes in nonplanar aromatic heterocyclic molecules

BROVELLI, SERGIO;TUBINO, RICCARDO;MEINARDI, FRANCESCO;
2007

Abstract

A comprehensive study of the photophysical properties of a series of monoaza[5]helicenes is presented on the basis of joint optical spectroscopy and quantum chemistry investigations. The molecules have been characterized by absorption and CW/time-resolved luminescence measurements. All quantities related to spin-orbit-coupling processes; such as intersystem crossing rates and radiative phosphorescence lifetimes, were found to depend strongly on the nitrogen position within the carbon backbone. Density functional theory and semiempirical quantum-chemical methods were used to evaluate the molecular geometries, the characteristics of the excited singlet and triplet states, and the spin-orbit coupling matrix elements. We demonstrate that the magnitude of spin-orbit coupling is directly con-elated with the degree of deviation from planarity. The trends from the calculated photophysical quantities, namely, radiative fluorescence and phosphorescence decay rates and intersystem crossing rates, of the mono-aza-helicenes are fully consistent with experiment.
Articolo in rivista - Articolo scientifico
DENSITY-FUNCTIONAL THEORY; CONFIGURATION-INTERACTION DESCRIPTION; ELECTRONIC-ABSORPTION-SPECTRA; EXCITED-STATE PROPERTIES; SPIN-ORBIT INTERACTIONS; HETEROAROMATIC MOLECULES; 2-PHOTON ABSORPTION; CIRCULAR-DICHROISM; ADIABATIC APPROXIMATION; NITROGEN HETEROCYCLICS
English
2007
111
42
10490
10499
none
Schmidt, K., Brovelli, S., Coropceanu, V., Beljonne, D., Cornil, J., Bazzini, C., et al. (2007). Intersystem crossing processes in nonplanar aromatic heterocyclic molecules. JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY, 111(42), 10490-10499 [10.1021/jp075248q].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/1641
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