95/05786 Chemistry of intermolecular hydrogen transfer processes in coal liquefaction

1995 ◽  
Vol 36 (6) ◽  
pp. 413
Keyword(s):  
Hydrogen Transfer ◽  
Coal Liquefaction ◽  
Transfer Processes ◽  
Intermolecular Hydrogen Transfer

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.

Intermolecular hydrogen transfer in unsaturated hydrocarbons induced by dimeric titanocene

1983 ◽  
Vol 48 (10) ◽  
pp. 2924-2936 ◽  
Author(s):  
Karel Mach ◽  
Lidmila Petrusová ◽  
Helena Antropiusová ◽  
Vladimír Hanuš ◽  
František Tureček ◽  
...  
Keyword(s):  
Hydrogen Transfer ◽  
Titanium Content ◽  
Esr Spectra ◽  
Stable Complex ◽  
Catalytic Complex ◽  
Substitution Reactions ◽  
Unsaturated Hydrocarbons ◽  
Linear Alkanes ◽  
Saturated And Aromatic Hydrocarbons ◽  
Intermolecular Hydrogen Transfer

μ-(η5 : η5-Fulvalene)-di-μ-hydrido-bis(η5-cyclopentadienyltitanium) and μ-(η5 : η5-fulvalene)-μ-chloro-μ-hydrido-bis(cyclopentadienyltitanium) form a thermally stable complex which catalyzes the intermolecular hydrogen transfer in unsaturated hydrocarbons, in addition to isomerizations and cyclizations. Cyclic hydrocarbons disproportionate under catalysis to saturated and aromatic hydrocarbons, while linear olefins yield predominantly linear alkanes and high molecular weight tar. The catalyst enables the hydrocarbon system to approach the thermodynamic equilibrium through a series of substitution reactions between alkyl- and allyltitanocene-like species and olefins and dienes. The catalytic complex was characterized by UV and ESR spectra. About one half of overall titanium content could be converted to mononuclear η3-allyltitanocene-like species, stable up to 400 °C. This exceptional thermal stability is ascribed to a firmly bound allyl containing ligand.

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