Time-resolved CIDNP study of hydrogen transfer in the photolysis of carbonyl-containing compounds

1989 ◽  
Vol 139 (2-3) ◽  
pp. 301-306 ◽  
Author(s):  
Yu.P. Tsentalovich ◽  
A.A. Obynochny ◽  
R.Z. Sagdeev
Keyword(s):  
Hydrogen Transfer ◽  
Time Resolved

scholarly journals Photoinduced Intramolecular Hydrogen Transfer Reaction of Ortho Nitrobenzyl Compounds

1999 ◽  
Vol 19 (1-4) ◽  
pp. 357-362 ◽  
Author(s):  
Hiroaki Takahashi ◽  
Yoshiki Watanabe ◽  
Makoto Sakai ◽  
Masanori Tachikawa
Keyword(s):  
Nitro Group ◽  
Absorption Spectra ◽  
Hydrogen Transfer ◽  
Transfer Reaction ◽  
Resonance Raman ◽  
Polar Solvents ◽  
Time Resolved ◽  
Hydrogen Transfer Reaction ◽  
Intramolecular Hydrogen

Time-resolved resonance Raman and absorption spectra have revealed that the photoinduced intramolecular hydrogen transfer reaction of ortho nitrobenzyl compounds is initiated by the abstraction of methylene hydrogen by the ortho nitro group to generate the ortho aci-nitro acid isomer. In polar solvents the ortho aci-nitro acid is dissociated into the aci-nitro anion and a proton, and the proton is captured by other hydrogen accepting sites, such as 2-pyridyl, 4-pyridyl and 4-nitro groups to generate the ortho N—H quinoid, para N—H quinoid and para aci-nitro acid isomers, respectively. For 2-nitroethylbenzene and 2- and 4-(2′-nitrobenzyl)pyridines the structure of the aci-nitro anion is very similar to that of their respective ortho aci-nitro acid, while for 2,4-dinitroethylbenzene the structure of the aci-nitro anion quite resembles that of the para aci-nitro acid.

Intramolecular hydrogen transfer in the o‐tolyl radical studied by time resolved absorption measurements

1986 ◽  
Vol 84 (3) ◽  
pp. 1943-1944 ◽  
Author(s):  
Teijiro Ichimura ◽  
Yuji Mori ◽  
Minoru Sumitani ◽  
Keitaro Yoshihara
Keyword(s):  
Hydrogen Transfer ◽  
Time Resolved ◽  
Intramolecular Hydrogen ◽  
Absorption Measurements

Excited state hydrogen transfer dynamics in phenol–(NH3)2 studied by picosecond UV-near IR-UV time-resolved spectroscopy

2020 ◽  
Vol 22 (10) ◽  
pp. 5740-5748
Author(s):  
Shun-ichi Ishiuchi ◽  
Junko Kamizori ◽  
Norihiro Tsuji ◽  
Makoto Sakai ◽  
Mitsuhiko Miyazaki ◽  
...  
Keyword(s):  
Excited State ◽  
Hydrogen Transfer ◽  
Transfer Reaction ◽  
Bound State ◽  
Intersystem Crossing ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Hydrogen Transfer Reaction ◽  
Near Ir

Intersystem crossing from 1πσ* to 3πσ* states traps excited state hydrogen transfer reaction in a bound state formed by 3ππ* and 3πσ* states.

scholarly journals Influence of local microenvironment on the double hydrogen transfer in porphycene

2020 ◽  
Vol 22 (30) ◽  
pp. 17117-17128
Author(s):  
Piotr Kasprzycki ◽  
Przemysław Kopycki ◽  
Arkadiusz Listkowski ◽  
Aleksander Gorski ◽  
Czesław Radzewicz ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Hydrogen Transfer ◽  
Time Resolved ◽  
Double Hydrogen

Time-resolved studies of the double hydrogen transfer in porphycene indicate strong coupling of the reaction to the dynamics of the local microenvironment.

Hydrogen transfer dynamics in a photoexcited phenol/ammonia (1:3) cluster studied by picosecond time-resolved UV-IR-UV ion dip spectroscopy

2007 ◽  
Vol 127 (23) ◽  
pp. 234304 ◽  
Author(s):  
Shun-ichi Ishiuchi ◽  
Makoto Sakai ◽  
Kota Daigoku ◽  
Kenro Hashimoto ◽  
Masaaki Fujii
Keyword(s):  
Hydrogen Transfer ◽  
Time Resolved

Effect of Niacin on Mitochondria of Allium Cepa Root Cells

1967 ◽  
Vol 25 ◽  
pp. 78-79
Author(s):  
M. Arif Hayat
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Hydrogen Transfer ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nicotinamide Adenine ◽  
Root Tips ◽  
Root Cells ◽  
Transfer Processes ◽  
Standard Procedures ◽  
A Cell ◽  
Critical Interest

Although it is recognized that niacin (pyridine-3-carboxylic acid), incorporated as the amide in nicotinamide adenine dinucleotide (NAD) or in nicotinamide adenine dinucleotide phosphate (NADP), is a cofactor in hydrogen transfer in numerous enzyme reactions in all organisms studied, virtually no information is available on the effect of this vitamin on a cell at the submicroscopic level. Since mitochondria act as sites for many hydrogen transfer processes, the possible response of mitochondria to niacin treatment is, therefore, of critical interest.Onion bulbs were placed on vials filled with double distilled water in the dark at 25°C. After two days the bulbs and newly developed root system were transferred to vials containing 0.1% niacin. Root tips were collected at ¼, ½, 1, 2, 4, and 8 hr. intervals after treatment. The tissues were fixed in glutaraldehyde-OsO4 as well as in 2% KMnO4 according to standard procedures. In both cases, the tissues were dehydrated in an acetone series and embedded in Reynolds' lead citrate for 3-10 minutes.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

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