Signaling Recognition Events with Fluorescent Sensors and Switches.

6. Rehybridization of the Acceptor (RICT) 3908 7. Planarization of the Molecule (PICT) 3909 III. Fluorescence Spectroscopy 3909 A. Solvent Effects and the Model Compounds 3909 1. Solvent Effects on the Spectra 3909 2. Steric Effects and Model Compounds 3911 3. Bandwidths 3913 4. Isoemissive Points 3914 B. Dipole Moments 3915 C. Radiative Rates and Transition Moments 3916 1. Quantum Yields and Radiationless Deactivation Processes 3916

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

The Stability of Cyclodextrin Complexes in Solution.

The application of self-assembled hosts as "molecular flasks" has precipitated a surge of interest in the reactivity and properties of molecules within well-defined confined spaces. The facile and modular synthesis of self-assembled hosts has enabled a variety of hosts of differing sizes, shapes, and properties to be prepared. This Review briefly highlights the various molecular flasks synthesized before focusing on their use as functional molecular containers--specifically for the encapsulation of guest molecules to either engender unusual reactions or unique chemical phenomena. Such self-assembled cavities now constitute a new phase of chemistry, which cannot be achieved in the conventional solid, liquid, and gas phases.

Functional Molecular Flasks : New Properties and Reactions within Discrete, Self-Assembled Hosts

The understanding of the dual fluorescence of certain aromatic systems has greatly advanced in recent years. The accompanying large charge separation has been shown to be linked to a twisted (or small overlap) arrangement of the chromophores. Recent theoretical models are able to describe the excited-state twisting of both single bonds (TICT compounds) and double bonds (olefins) in a unified picture. These models can help to elucidate the photophysical behavior of many organic, inorganic, and biologically relevant compounds, and their application to laser dyes and fluorescent probes provides a route to new “tailor-made” fluorescent materials. Applied to the primary processes of vision and photosynthesis, these models can lead to a deeper understanding of basic photobiological processes.

Charge Separation in Excited States of Decoupled Systems—TICT Compounds and Implications Regarding the Development of New Laser Dyes and the Primary Process of Vision and Photosynthesis

Intramolecular exciplex emission from aqueous .beta.-cyclodextrin solutions

— The dual fluorescence of 4-(N, N-dimethylamino)benzonitrile and 4-(N, N-diethylamino)-benzonitrile (DMABN and DEABN, respectively), has been studied in aqueous solutions of cyclodextrins. Fluorescence parameters (peak maximum, lifetime, and relative intensity) have been measured and are found to be consistent with the formation of complexes of probe and cyclodextrin. Enhanced emission of the twisted internal charge transfer state (TICT) fluorescence is observed in cyclodextrin, with the greatest effect for the DMABN/α-cyclodextrin system. Our results promote further understanding of both the photophysical behavior of DMABN and the complexation of probe with cyclodextrin. The use of dialkylaminobenzonitriles as polarity probes is discussed.

Dialkylaminobenzonitriles as fluorescence polarity probes for aqueous solutions of cyclodextrins

Mechanisms for the photooxidation of protoporphyrin IX in solution

The phosphorescence of the 4-bromo-l-naphthoyl group is readily quenched by molecular oxygen in homogeneous solvents. However, when this lumophore is complexed with γ-cyclodextrin in aqueous solution at room temperature, its phosphorescence is observed even under 1 atm of oxygen! Phosphorescence decay data indicated that two types of probe/cyclodcxtrin complexes are formed with lifetimes of 600 u,s and 3.5 ms. Oxygen completely quenches the fast decay, but only partially quenches the slow decay.

Remarkable inhibition of oxygen quenching of phosphorescence by complexation with cyclodextrins

Photochemical reactivity in organized assemblies. 30. Self-sensitized photooxidation of protoporphyrin IX derivatives in aqueous surfactant solutions; product and mechanistic studies

G. Sidney Cox

Papers

Intramolecular exciplex emission from aqueous .beta.-cyclodextrin solutions

Dialkylaminobenzonitriles as fluorescence polarity probes for aqueous solutions of cyclodextrins

Mechanisms for the photooxidation of protoporphyrin IX in solution

Remarkable inhibition of oxygen quenching of phosphorescence by complexation with cyclodextrins

Photochemical reactivity in organized assemblies. 30. Self-sensitized photooxidation of protoporphyrin IX derivatives in aqueous surfactant solutions; product and mechanistic studies