Related Experiment Video
Updated: Jun 2, 2026
08:31
Luminescence Resonance Energy Transfer to Study Conformational Changes in Membrane Proteins Expressed in Mammalian Cells
Published on: September 16, 2014
Luminescent charge-transfer complexes: tuning emission in binary fluorophore mixtures
Maneesh D Gujrati1, N S Saleesh Kumar, Adrienne S Brown
1Center for Supramolecular Science and Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33124, United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|May 10, 2011
Summary
Solid-state charge-transfer (CT) complexes using naphthalene diimide (NDI) derivatives exhibit tunable emission. This fluorescence, dependent on donor HOMO energy, enables applications as imaging agents.
Area of Science:
- Materials Science
- Supramolecular Chemistry
- Photophysics
Background:
- Charge-transfer (CT) complexes are formed between electron-poor and electron-rich molecules.
- Naphthalene diimide (NDI) derivatives are known electron acceptors.
- Understanding solid-state emission properties of CT complexes is crucial for their applications.
Purpose of the Study:
- To investigate the photophysical properties of CT complexes formed by NDI derivatives and electron-rich donors.
- To explore the relationship between molecular structure, solid-state packing, and luminescence.
- To assess the potential of these CT complexes as imaging agents.
Main Methods:
- Synthesis of CT complexes using NDI derivatives and various electron-rich donors.
- Spectroscopic analysis (UV-Vis absorption, fluorescence) in solution and solid-state.
- Crystallographic analysis of selected complexes.
- Evaluation of CT complex fluorescence for imaging applications.
Main Results:
- Solutions of CT complexes were nonemissive.
- Solid-state complexes and aqueous suspensions exhibited emission.
- Luminescence intensity correlated with the highest occupied molecular orbital (HOMO) energy of the electron donor.
- Crystallographic data revealed columnar packing and significant frontier molecular orbital (FMO) overlap in a pyrene-NDI complex.
- Fluorescent CT particles were successfully demonstrated as imaging agents.
Conclusions:
- Solid-state emission of NDI-based CT complexes is achievable and tunable.
- HOMO energy of the donor and FMO overlap are key factors governing luminescence.
- These fluorescent CT complexes show promise for bioimaging applications.
- Further exploration of FMO energies and topologies can lead to new luminescent CT materials.
Related Concept Videos
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...
01:14Photoluminescence: Applications
Photoluminescence offers a wide range of applications due to its inherent sensitivity and selectivity. This technique allows for both direct and indirect analyses of the analyte. Direct quantitative analysis is possible when the analyte exhibits a favorable quantum yield for fluorescence or phosphorescence. However, an indirect analysis may be feasible if the analyte is not fluorescent or phosphorescent, or if the quantum yield is unfavorable. Indirect methods include reacting the analyte with...
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...
01:37Super-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.
01:25Fluorescence and Phosphorescence: Instrumentation
Fluorometers and spectrofluorometers are two types of instruments used for measuring molecular fluorescence. These instruments differ in how they select excitation and emission wavelengths and the type of light sources they utilize. Fluorometers use absorption interference filters to choose excitation and emission wavelengths. The excitation source in a fluorometer is typically a low-pressure mercury vapor lamp that emits intense lines distributed throughout the ultraviolet and visible regions.