Related Experiment Video
Updated: Aug 5, 2026
10:21
Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
Published on: October 5, 2019
Coumarin-Based Hybrids: From Linear Photophysical Properties to Multiphoton Excitation Behavior
Luis M G Abegão1, Leonardo R de Almeida2, Juliana G M Lima2
1Sensors, Instrumentation and Applied Photonics Group, Department of Physics, Federal University of Sergipe, São Cristóvão 49107-230, Brazil.
ACS Physical Chemistry Au
|July 25, 2026
Summary
This study explores coumarin derivatives for optical applications, finding that a hydroxylated compound exhibits superior fluorescence quantum yield and lifetime, making it ideal for photoluminescent probing.
Area of Science:
- Photonic materials
- Organic electronics
- Molecular spectroscopy
Background:
- Coumarin derivatives are versatile photonic building blocks with significant light-matter interactions.
- Their tunable optical properties are crucial for linear and nonlinear optical applications.
- Understanding structure-property relationships is key to designing advanced photoluminescent materials.
Purpose of the Study:
- To investigate the linear optical properties and multiphoton excitation response of novel coumarin derivatives.
- To compare the photophysical characteristics of coumarin coupled with benzothiazole and benzimidazole moieties.
- To identify promising candidates for photoluminescent probing applications.
Main Methods:
- Synthesis and characterization of four coumarin-based derivatives.
- Spectroscopic analysis including absorption and emission maxima, molar absorptivity, and transition dipole moments.
- Femtosecond laser-based multiphoton excitation fluorescence experiments.
Main Results:
- Three derivatives (7-diethylamino-coumarin-benzothiazole, 6-bromo-coumarin-benzothiazole, 7-diethylamino-coumarin-benzimidazole) showed similar absorption (~423-428 nm) and emission (~485 nm) peaks.
- Diethylamino-substituted compounds exhibited higher molar absorptivity and transition dipole moments compared to the bromo-substituted one.
- The 7-hydroxyl-coumarin-methyl-benzimidazole derivative displayed a larger Stokes shift, lower molar absorptivity, but high fluorescence quantum yield (~48%) and excited-state lifetime (~3 ns).
Conclusions:
- Coumarin derivatives with benzothiazole and benzimidazole moieties possess tunable photophysical properties.
- The 7-hydroxyl-coumarin-methyl-benzimidazole derivative is identified as a highly promising candidate for photoluminescent probing due to its superior fluorescence efficiency.
- These findings contribute to the development of advanced materials for optical and photonic technologies.
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
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this process,...
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
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...
01:21IR Absorption Frequency: Hybridization
Hydrocarbons such as alkanes, alkenes, and alkynes show characteristic C–H stretching absorption bands. These IR stretching frequencies depend on the hybridization of the involved carbon atom and can be explained in terms of the s character of each hybridized atomic orbital.
Among the sp, sp2, and sp3 hybridized orbitals, sp orbitals have the maximum s character (50%). Consequently, the electrons are held more closely to the nucleus, resulting in stronger and shorter C–H bonds that stretch at a...
Among the sp, sp2, and sp3 hybridized orbitals, sp orbitals have the maximum s character (50%). Consequently, the electrons are held more closely to the nucleus, resulting in stronger and shorter C–H bonds that stretch at a...
01:23Photoluminescence: Fluorescence and Phosphorescence
Photoluminescence is a process where a molecule absorbs light energy and re-emits it in the form of light. This phenomenon occurs when a substance absorbs photons, promoting its electrons to higher energy level excited states, followed by a relaxation process in which the electrons return to their original ground state energy levels and emit light. Photoluminescence is widely observed in various materials, including semiconductors, and organic and inorganic compounds.
A pair of electrons in a...
A pair of electrons in a...