Reactivity of Some Cobalt(III) Complexes toward Photochemically Produced Hydrogen Atoms and Solvated Electrons in Aqueous Solution1

1966 ◽  
Vol 70 (11) ◽  
pp. 3389-3394 ◽  
Author(s):  
John F. Endicott ◽  
Morton Z. Hoffman
Keyword(s):  
Hydrogen Atoms ◽  
Solvated Electrons

Inorganic radicals of relevance to biological systems

1985 ◽  
Vol 311 (1152) ◽  
pp. 451-472 ◽  
Keyword(s):  
Redox Reactions ◽  
Biological Systems ◽  
Spin Trapping ◽  
Redox Cycle ◽  
Hydrogen Atoms ◽  
Solvated Electrons

There is little doubt that the most important inorganic radicals involved in biological systems are those which are intermediates in the oxygen-water redox cycle, i.e. OH’, O - 2 and HO’ 2' . Aspects of the structures and reactivities of these radicals are considered, together with methods of detection. In particular, the use of e.s.r. spectroscopy is outlined, including rapid-freeze and spin-trapping techniques. Attention is called to comparisons and contrasts between these radicals and corresponding sulphur-centred radicals, although these are not strictly ‘inorganic’. The oxygen-centred radicals are usually generated in vivo by redox reactions, but they are also of importance in radioly tic processes because they are formed from water. Other Radicals formed in this way whose structures and reactivities are considered include solvated electrons and hydrogen atoms.

Conversion of Solvated Electrons into Hydrogen Atoms in the Photo‐ and Radiation Chemistry of Aqueous Solutions

1962 ◽  
Vol 37 (10) ◽  
pp. 2488-2495 ◽  
Author(s):  
Joshua Jortner ◽  
Michael Ottolenghi ◽  
Joseph Rabani ◽  
Gabriel Stein
Keyword(s):  
Aqueous Solutions ◽  
Radiation Chemistry ◽  
Hydrogen Atoms ◽  
Solvated Electrons

Effect of Pressure on the Rates of Reaction of Hydrogen Atoms in the Radiolysis of Liquid Ethanol

1973 ◽  
Vol 51 (12) ◽  
pp. 2033-2040 ◽  
Author(s):  
Kamal N. Jha ◽  
Gordon R. Freeman
Keyword(s):  
Charge Transfer ◽  
Hydrogen Atom ◽  
Aromatic Ring ◽  
Rate Constants ◽  
Hydrogen Yield ◽  
Hydrogen Atoms ◽  
Solvated Electrons ◽  
Effect Of Pressure

Competition between the reactions[Formula: see text]and[Formula: see text]was measured at 296 K at 1 bar and 5.4 kbar. Values of k5/k3 at 1 bar and (ΔV5≠ − ΔV3≠) averaged between 1 bar and 5.4 kbar for several solutes S are: cyclohexene, 56, + 2.7 cm3/mol; hexene-1, 71, + 2.6 cm3/mol; phenol, 25, −3.8 cm3/mol; benzene, 12, −6.5 cm3/mol. The volume of activation of hydrogen atom addition to the aromatic ring is about 8 cm3/mol more negative than that of addition to a mono-olefin. Rate constants of reaction of solvated electrons with these solutes at 295 K, measured by the pulse-radiolysisspectroscopy technique, are (M−1 s−1): cyclohexene, <1 × 104; hexene-1, 1 × 105; benzene, 4 × 106; phenol, 5 × 107. The phenol reaction with e−solv does not reduce the hydrogen yield by a proportionate amount, so phenol "catalyses" the decomposition of e−solv to form hydrogen, perhaps via C6H5OH−solv → C6H5O−solv + H. The scavenging of hydrogen precursors by hexene-1, benzene, and aniline in n-hexane, reported in ref. 6, had [Formula: see text], −6, and −4 cm3/mol, respectively, all three of which may be attributed to hydrogen atom reactions. The yields of hydrogen from solutions of neohexane in cyclopentane at 1 bar and 5.4 kbar indicate that charge transfer occurs from cyclopentane to neohexane, and that the probability of charge transfer is independent of pressure. The methane yields from these solutions indicate that the decomposition of the neohexane ion formed by charge transfer from cyclopentane, to form methane, is inhibited by pressure.

Remarks on the diffuse interstellar lines

1967 ◽  
Vol 31 ◽  
pp. 91-93 ◽  
Author(s):  
G. Herzberg
Keyword(s):  
Hydrogen Atoms ◽  
Interstellar Gas

It is suggested that the diffuse interstellar lines are produced in the interstellar gas by molecules consisting of a few hydrogen atoms and one other atom, such as CH4+ or NH4. Diffuseness of the lines is assumed to result from predissociation of these molecules.

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