E.S.R. studies of the oxidative coupling of some bisphenols

1975 ◽  
Vol 28 (2) ◽  
pp. 343 ◽  
Author(s):  
SM Colegate ◽  
FR Hewgill ◽  
GB Howie
Keyword(s):  
Carbon Monoxide ◽  
Alkaline Solution ◽  
Unpaired Electron ◽  
Oxidative Coupling ◽  
Radical Anion ◽  
Neutral Solution

E.s.r. spectroscopy and the identification of products show that oxidation of 3,5,3?,5?-tetra-t-butyl-4,4?-dihydroxybenzophenone in neutral solution gives 3,5,3?,5?-tetra-t-butyldipheno-4,4?-quinone. If oxygen is present 2,6-di-t-butyl-p-benzoquinone is also formed. The evolution of carbon monoxide suggests that bis-spirodienones are intermediate in the formation of these products. E.s.r. spectra of radicals produced by oxidation of 3,5,3?,5?-tetra-t-butylbiphenyl-4,4?- dio and 2,6-di-t-butylhydro-quinone have been re-examined. In alkaline solution 3,5,3?,5?-tetra-t-butyl-4,4?-dihydroxybenzo-phenone is oxidized to a radical anion in which the unpaired electron is delocalized over both rings. ��� Attempts to detect unsymmetrical bisaryloxy radicals were unsuccessful, 3?,5?-di-t-butyl-4,4?-dihydroxy-3,5-dimethoxybenzophenone forming only the radical derived from the syringoyl portion, and 2,4?- oxydiphenol ether forming only the 4?-oxy radical. Comparison with the observation of both radicals when a mixture of guaiacol and p- methoxyphenol was oxidized suggests that C-O-C coupling in 2,4?- oxydiphenol proceeds by direct radical pairing.

Some reactions of hydrazine with ruthenium compounds

1970 ◽  
Vol 48 (2) ◽  
pp. 351-355 ◽  
Author(s):  
F. Bottomley
Keyword(s):  
Alkaline Solution ◽  
Neutral Solution ◽  
Ammine Complexes ◽  
Ruthenium Compounds

Some reactions of hydrazine with pentachloroaquoruthenite(III) and ammine complexes of ruthenium(II) and ruthenium(III) have been investigated in acid, neutral, and alkaline solution. In neutral solution it has been shown that hydrazine monohydrochloride oxidized hexaammineruthenium(II) to hexaammineruthenium(III). In alkaline solution nitrogenpentaamrnineruthenium(II) was formed, and a mechanism for this reaction is postulated.

Oxidative coupling of amines and carbon monoxide catalyzed by palladium complexes. Mono- and double carbonylation reactions promoted by iodine compounds

1990 ◽  
Vol 68 (9) ◽  
pp. 1544-1547 ◽  
Author(s):  
Ilan Pri-Bar ◽  
Howard Alper
Keyword(s):  
Carbon Monoxide ◽  
Oxidative Coupling ◽  
Room Temperature ◽  
Palladium Complexes ◽  
Secondary Amines ◽  
Primary Amines ◽  
Palladium Acetate ◽  
Principal Product ◽  
Iodine Compounds ◽  
Primary And Secondary Amines

Iodine is an effective promoter for the carbonylation of primary and secondary amines to ureas using palladium acetate as the catalyst and a base (e.g. K2CO3) in acetonitrile (3 h at 95 °C and 2.7 atm). Oxamides are formed in excellent yields when secondary amines are carbonylated in the presence of iodide ion and oxygen, while primary amines give ureas as the principal product at 95 °C, and oxamide at room temperature. Keywords: oxamides, ureas, double carbonylation, amines.

THE MECHANISM OF THE ALCOHOLYSIS OF ALIPHATIC NITRITES: I. ALCOHOLYSIS OF 1-METHYLHEPTYL NITRITE IN ALKALINE AND NEUTRAL SOLUTION

1961 ◽  
Vol 39 (4) ◽  
pp. 940-946 ◽  
Author(s):  
A. D. Allen ◽  
G. R. Schonbaum
Keyword(s):  
Alkaline Solution ◽  
Reaction Rate ◽  
Ion Concentration ◽  
Neutral Solution ◽  
Neutral Reaction ◽  
Polarimetric Study ◽  
Kinetics Of ◽  
Asymmetric Carbon

A polarimetric study of the kinetics of the alcoholysis of 1-methylheptyl nitrite in alkaline solution has shown that the reaction rate is proportional to both the nitrite and alkoxide ion concentration. The asymmetric carbon center is not involved in the reaction. In strictly neutral solution no reaction occurs; the commonly observed "neutral" reaction is attributed to traces of acid formed in the decomposition of the nitrite ester. The mechanism of the reactions is discussed.

Photolysis of pyridinoline, a cross-linking amino acid of collagen, by ultraviolet light

1982 ◽  
Vol 60 (5) ◽  
pp. 525-529 ◽  
Author(s):  
Sachiko Sakura ◽  
Daisaburo Fujimoto ◽  
Kikuo Sakamoto ◽  
Akio Mizuno ◽  
Katsutoshi Motegi
Keyword(s):  
Amino Acid ◽  
Ultraviolet Light ◽  
Alkaline Solution ◽  
Absorption Maximum ◽  
Acidic Solution ◽  
Cross Linking ◽  
Neutral Solution ◽  
Pyridinium Ring ◽  
Optimum Wavelength ◽  
Amino Acid Analyser

Pyridinoline, a cross-linking amino acid of collagen, was degraded by irradiation of ultraviolet light. The decomposition rate varied with pH of the solution and wavelength of irradiation light. The maximum of the degradation rate at individual pH coincides with the ultraviolet absorption maximum. Namely, it was maximally degraded by irradiation at 295 nm in acidic solution and at 325 nm in neutral and alkaline solution. At the optimum wavelength, the photolysis occurred more rapidly in neutral and alkaline solution than in acidic solution. The quantum yield in neutral solution was approximately 0.11 and independent of wavelength. One of the photolysis products was identified as hydroxylysine on an amino acid analyser, indicating that the cleavage of the pyridinium ring occurred.

Evidence For a Water-Stabilised Ion Radical Complex: Photoelectron Spectroscopy and Ab Initio Calculations

2020 ◽  
Vol 73 (8) ◽  
pp. 693
Author(s):  
Timothy R. Corkish ◽  
Christian T. Haakansson ◽  
Allan J. McKinley ◽  
Duncan A. Wild
Keyword(s):  
Water Molecule ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Unpaired Electron ◽  
Photoelectron Spectroscopy ◽  
Radical Anion ◽  
Photoelectron Spectrum ◽  
The Other ◽  
Spin Orbit ◽  
Anion Complex

A photoelectron spectrum corresponding to an unknown 174m/z anion complex has been recorded. Initially believed to be I−…CH3CH2OH (173m/z), the spectrum has been assigned as belonging to that of an I−…H2O…CH3CH2 radical anion complex. The major peaks in the photoelectron spectrum occur at 3.54eV and 4.48eV as the 2P3/2 and 2P1/2 spin-orbit states of iodine respectively. Ab initio calculations were performed in order to rationalise the existence of the complex, with all structures converging to a ‘ring-like’ geometry, with the iodide anion bound to both the water molecule as well as a hydrogen of the ethyl radical, with the other hydrogen of water bound to the unpaired electron site of the ethyl. Simulated vertical detachment energies of 3.59eV and 4.53eV were found to be in agreement with the experimental results.

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