다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

비만아 부모의 돌봄 경험: q 방법론

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

Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

9.2. Protein-Based Hg(II) Detectors 3467 9.3. Oligonucleotide-Based Hg(II) Detector 3467 9.4. DNAzyme-Based Hg(II) Detectors 3469 9.5. Antibody-Based Hg(II) Detector 3469 10. Mercury Detectors Based on Materials 3469 10.1. Soluble and Fluorescent Polymers 3469 10.2. Membranes, Films, and Fibers 3471 10.3. Micelles 3473 10.4. Nanoparticles 3473 11. Perspectives 3474 12. Addendum 3475 12.1. Small Molecules 3475 12.2. Biomolecules 3477 12.3. Materials 3477 13. List of Abbreviations 3477 14. Acknowledgments 3478 15. References 3478

Tools and tactics for the optical detection of mercuric ion.

The excited-state intramolecular proton transfer (ESIPT) of 2-(2‘-hydroxyphenyl)benzimidazole (HBI) has been studied using absorbance, steady-state, and time-resolved emission spectroscopies in cyclodextrins (β-, γ-, and 2,6-di-O-methyl-β-cyclodextrins) and in binary aqueous solvent mixtures. The spectral characteristics of HBI in cyclodextrins and binary solvent mixtures (dioxane:water, MeOH:water, and solutions of cyclohexane containing MeOH and trifluoroethanol) are compared to further study the effects of various microenvironments on the ground and excited-state properties of the molecule. The intermolecular interactions of HBI with cyclodextrins and various solvents appear to weaken intramolecular hydrogen bonding in HBI and facilitate the formation of strong intermolecular hydrogen bonds with the various cyclodextrins and solvent molecules. The acquired data are used to suggest the formation of a zwitterionic structure of HBI in cyclodextrins.

Excited-State Intramolecular Proton Transfer of 2-(2‘-Hydroxyphenyl)benzimidazole in Cyclodextrins and Binary Solvent Mixtures

A series of amino acid-based gelators N-(n-alkylcarbamoyl)-l-alanine were synthesized, and their gelation abilities in a series of organic solvents were tested. No gelation was observed in pure solvents employed. All the amphiphilic molecules were found to form stable organogels in the solvents in the presence of a small amount of water, methanol, or urea. The volume of solvent gelled by a given amount of the gelator was observed to depend upon the volume of added water. The gelation behavior of the amphiphiles in a given solvent containing a known volume of water was compared. The effects of chirality and substitution on the acid group on the gelation ability were examined. Although the corresponding N-(n-tetradecylcarbamoyl)-dl-alanine was found to form only weak organogel in pure solvents, the achiral amphiphilic compound N-(n-tetradecylcarbamoyl)-β-alanine, however, did not form gel in the absence of water. The methyl ester of N-(n-tetradecylcarbamoyl)-l-alanine was also observed to form gels in the s...

Water-Induced Physical Gelation of Organic Solvents by N-(n-Alkylcarbamoyl)-l-alanine Amphiphiles

The absorption and fluorescence spectra of 2-(4'-(N,N-dimethylamino)phenyl)benzothiazole (DMAPBT) and 2-(4'-(N,N-dimethylamino)phenyl)benzimidazole (DMAPBI) have been recorded in solvents of different polarity and hydrogen-bonding nature. In all the solvents, a dual fluorescence is observed for both the compounds. The normal Stokes-shifted emission (B) originates from a locally excited π * electronic state, and the large Stokes-shifted band (A) is due to emission from a twisted intramolecular charge-transfer (TICT) state. The dual fluorescence observed, even in nonpolar solvents, indicates that the energy of the TICT state is always lower than that of the locally excited state

Dual Fluorescence of 2-[4-(Dimethylamino)phenyl]benzothiazole and Its Benzimidazole Analog: Effect of Solvent and pH on Electronic Spectra

The absorption and fluorescence spectra of 2-(2-aminophenyl)-, 2-(3-aminophenyl)-, and 2-(4-aminophenyl)benzothiazoles (o-APBT, m-APBT, and p-APBT, respectively) have been studied in different solvents and at various acid/base concentrations. The ultraviolet and fluorescence spectra and the low pKa value for the monocation–neutral equilibrium have indicated the presence of an intramolecular hydrogen bond (IHB) in o-APBT in the S0 state. Excited state intra-molecular proton transfer (ESIPT) in o-APBT, gives rise to a non-fluorescent phototautomer. Large solvatochromic shifts in polar solvents have indicated the increase in the dipolemoment of m-APBT in S1 state. It has been observed that in protic solvents, m-APBT forms a complex with solvent molecule in the S1 state. The equilibrium constants for different prototropic equilibria of the molecules have been determined in both S0 and S1 states. The absorption and fluorescence spectra of the prototropic species have been explained and compared with those of 2...

Solvatochromism and Prototropism in 2-(Aminophenyl)benzothiazoles

The physicochemical properties, such as critical micelle concentration (cmc), surface tension at cmc (γcmc), and surface activity parameters of the mixtures of a new amino acid-based zwitterionic surfactant, N-(n-dodecyl-2-aminoethanoyl)-glycine (C12Gly) and an anionic surfactant, sodium dodecyl sulfate (SDS) at different molar fractions, X1 (= [C12Gly]/([C12Gly] + [SDS])) of C12Gly were studied. A synergistic interaction was observed between the surfactants in mixtures of different X1. The self-organization of the mixtures at different molar fractions, concentrations, and pH was investigated. Fluorescence depolarization studies in combination with dynamic light scattering, and transmission electron microscopic and confocal fluorescence microscopic images suggested the formation of bilayer vesicles in dilute solutions of SDS rich mixtures with X1 ≤ 0.17 in the pH range 7.0 to 9.0. However, the electronic micrographs showed structures with fingerprint-like texture in moderately dilute to concentrated C12Gl...

Joykrishna Dey

Papers

Excited-State Intramolecular Proton Transfer of 2-(2‘-Hydroxyphenyl)benzimidazole in Cyclodextrins and Binary Solvent Mixtures

Water-Induced Physical Gelation of Organic Solvents by N-(n-Alkylcarbamoyl)-l-alanine Amphiphiles

Dual Fluorescence of 2-[4-(Dimethylamino)phenyl]benzothiazole and Its Benzimidazole Analog: Effect of Solvent and pH on Electronic Spectra

Solvatochromism and Prototropism in 2-(Aminophenyl)benzothiazoles

Interaction Between Zwitterionic and Anionic Surfactants: Spontaneous Formation of Zwitanionic Vesicles