Related Experiment Video
Updated: May 25, 2026
10:21
Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
Published on: October 5, 2019
Conformations and fluorescence of encapsulated stilbene
Demeter Tzeli1, Giannoula Theodorakopoulos, Ioannis D Petsalakis
1Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou, Athens 116 35, Greece.
Journal of the American Chemical Society
|February 1, 2012
Summary
Encapsulation affects trans-stilbene fluorescence. In large capsules, fluorescence persists, but in small capsules, it is quenched due to geometric distortion and non-radiative decay.
Area of Science:
- Computational Chemistry
- Photophysics
- Supramolecular Chemistry
Background:
- Stilbene's fluorescence is sensitive to its molecular environment.
- Controlling molecular conformation and photophysical properties within confined spaces is of significant interest.
Purpose of the Study:
- To theoretically interpret experimental findings on stilbene's fluorescence in capsules.
- To elucidate the impact of encapsulation on stilbene's conformation and emission spectra.
Main Methods:
- Density Functional Theory (DFT) and Time-Dependent DFT (TDDFT) calculations.
- Employing multiple levels of theory including B3LYP, CAM-B3LYP, M06-2X, PBE0, and ωB97X-D.
- Utilizing the 6-31G(d,p) basis set for all computations.
Main Results:
- Calculated spectra align with experimental observations.
- Trans-stilbene fluorescence is maintained in large capsules but quenched in small ones.
- Encapsulation in a small cage distorts the ground state and leads to non-radiative decay via conical intersection.
Conclusions:
- Molecular geometry changes within small capsules inhibit fluorescence.
- The size and geometry of the capsule significantly influence stilbene's photophysical behavior.
- Theoretical calculations provide a robust explanation for experimental results on encapsulated stilbene.
Related Concept Videos
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:26Variables Affecting Phosphorescence and Fluorescence
Fluorescence and phosphorescence are essential phenomena in fields like analytical chemistry, biological imaging, and materials science, where they detect molecular properties and visualize cellular structures. Understanding the variables that influence these luminescent behaviors is crucial for maximizing accuracy and efficiency in their applications. These variables can broadly be grouped into chemical structure, solvent properties, and external conditions, each playing a distinct role in...
01:28Stability of Conjugated Dienes
Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
01:37Super-resolution Fluorescence Microscopy
Super-resolution fluorescence microscopy (SRFM) provides a better resolution than conventional fluorescence microscopy by reducing the point spread function (PSF). PSF is the light intensity distribution from a point that causes it to appear blurred. Due to PSF, each fluorescing point appears bigger than its actual size, and it is the PSF interference of nearby fluorophores that causes the blurred image. Various approaches to achieving higher resolution through SRFM have recently been developed.
01:32UV–Vis Spectroscopy of Conjugated Systems
Organic compounds with conjugated double bonds show strong absorption features in the UV–visible region of the electromagnetic spectrum attributed to π → π* electronic excitations. Generally, a UV–vis absorption spectrum is recorded as a plot of absorbance vs wavelength. The wavelength of maximum absorbance, which manifests as a peak in the absorption spectrum, is denoted as λmax.
One of the factors influencing λmax is the extent of conjugation in the...
One of the factors influencing λmax is the extent of conjugation in the...