Toshiaki Ogiwara

Bio: Toshiaki Ogiwara is an academic researcher. The author has contributed to research in topics: Dissociation (chemistry) & Excited state. The author has an hindex of 2, co-authored 2 publications receiving 62 citations.

NaCl effect on the excited-state proton dissociation reaction of naphthols: water structure in the presence of NaCl

Abstract: The NaCl effect on the proton dissociation reaction in water at 300 K has been studied by means of nanosecond and picosecond spectroscopy with fluorimetry. The proton dissociation rate constant k/sub 1/ decreased with an increase of NaCl according to the equation k/sub 1/ = k/sub 0/((H/sub 2/O)/sub 4/)(1 - ..cap alpha..(NaCl)), where k/sub 0/ denotes the second-order rate constant for the proton transfer from excited naphthols to water clusters (H/sub 2/O)/sub 4/ and ..cap alpha.. is a constant value. This means that the decrease in the k/sub 1/ value is caused by NaCl-induced destruction of water clusters resulting in production of the hydrated ions (Na/sup +/)/sub hyd/ and (Cl/sup -/)/sub hyd/. The average hydration number of Na/sup +/ or Cl/sup -/ in water is obtained to be 4.4 or 6.6, respectively. The kinetic H-D isotope effect for k/sub 1/ in the presence of NaCl was also examined.

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

Abstract: 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

Excited-state proton transfer reactions I. Fundamentals and intermolecular reactions

Abstract: Theoretical models that have been proposed and applied to proton transfer reactions are reviewed in this work. Simple models, like the Eigen model, Marcus theory and the intersecting state model, are applied to excited-state intermolecular proton transfers. The kinetics and thermodynamics of proton transfers occuring in the singlet states of aromatic molecules with OH, NH3+, NH2 and CO substituents are reviewed.

Fluorescent PET (Photoinduced Electron Transfer) sensors as potent analytical tools

Abstract: Fluorescent sensors are an important part of the analytical scientist's toolbox. The use of fluorescent PET (Photoinduced Electron Transfer) sensors has seen particular growth in recent times. This Critical Review discusses recent growth areas in fluorescent PET sensors by emphasizing the modular features of the ‘fluorophore–spacer–receptor’ design. The occurrence of the dipicolylamine receptor in PET sensor designs is critically examined as a case in point.