Chapter VII: The Dissociation of Molecular Oxygen, The Recombination of Oxygen Atoms and Isotopic Exchange with Molecular Oxygen

1983 ◽  
pp. 180-199
Keyword(s):  
Molecular Oxygen ◽  
Isotopic Exchange ◽  
Oxygen Atoms

scholarly journals Molecular oxygen generation from the reaction of water cations with oxygen atoms

2019 ◽  
Vol 150 (20) ◽  
pp. 201103 ◽  
Author(s):  
Ryan C. Fortenberry ◽  
Tarek Trabelsi ◽  
Brent R. Westbrook ◽  
Weston A. Del Rio ◽  
Joseph S. Francisco
Keyword(s):  
Molecular Oxygen ◽  
Oxygen Generation ◽  
Oxygen Atoms

Hydroxylation of the C132 and C18 carbons of chlorophylls by heme and molecular oxygen

2015 ◽  
Vol 19 (09) ◽  
pp. 1007-1013 ◽  
Author(s):  
Patrick C. Loughlin ◽  
Robert D. Willows ◽  
Min Chen
Keyword(s):  
Aqueous Solution ◽  
Molecular Oxygen ◽  
Chlorophyll A ◽  
Oxidation Products ◽  
Chlorophyll B ◽  
Need For Care ◽  
Photosynthetic Organisms ◽  
Major Oxidation ◽  
Oxygen Atoms

Following extraction from photosynthetic organisms, chlorophylls are prone to reactions including demetalation, dephytylation and specific oxidations of the exocyclic ring E, termed allomerizations. Allomerization of chlorophylls has been well-characterized in methanol and to a lesser extent in aqueous solution. Here we detail novel allomerization-like reactions of chlorophyll a and chlorophyll b. In the presence of heme, detergent-solubilized chlorophyll a is hydroxylated at its C 132 position in ring E and, surprisingly, the C 18 position in ring D. Two major oxidation products are synthesized — a C 132- OH and a C 132- OH , C 18- OH derivative of chlorophyll a. We track the origin of the oxygen atoms added in these hydroxylated chlorophylls using 18 O 2 labeling and demonstrate that the additional oxygen atoms are derived from molecular oxygen. A similar heme-catalyzed reaction is also observed using chlorophyll b as a substrate. These results highlight the need for care when dealing with extracted chlorophylls and demonstrate an unusual hydroxylation of the C 18 position of chlorophylls in the presence of heme.

Isotopic exchange between molecular oxygen and synthetic zeolites

1971 ◽  
Vol 20 (4) ◽  
pp. 754-755
Author(s):  
Kh. M. Minachev ◽  
E. N. Savost'yanov ◽  
D. A. Kondrat'ev ◽  
Sui Nu Ch'ang ◽  
G. V. Antoshin
Keyword(s):  
Molecular Oxygen ◽  
Isotopic Exchange ◽  
Synthetic Zeolites
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