Electron-transfer-induced photocyclization reactions of arene-iminium salt systems. Effects of cation-diradical deprotonation and desilylation on the nature and efficiencies of reaction pathways followed

1987 ◽  
Vol 109 (9) ◽  
pp. 2738-2745 ◽  
Author(s):  
Alexander J. Y. Lan ◽  
Robert O. Heuckeroth ◽  
Patrick S. Mariano
Keyword(s):  
Electron Transfer ◽  
Reaction Pathways ◽  
Iminium Salt ◽  
Salt Systems

Arene-iminium salt electron-transfer photochemistry. Mechanistically interesting photoaddition processes

1987 ◽  
Vol 109 (9) ◽  
pp. 2728-2737 ◽  
Author(s):  
Robert M. Borg ◽  
Robert O. Heuckeroth ◽  
Alexander J. Y. Lan ◽  
Suzanne L. Quillen ◽  
Patrick S. Mariano
Keyword(s):  
Electron Transfer ◽  
Iminium Salt

Mechanistic study of a manganese porphyrin catalyst for on-demand production of chlorine dioxide in water

2015 ◽  
Vol 19 (01-03) ◽  
pp. 492-499 ◽  
Author(s):  
Scott D. Hicks ◽  
Silei Xiong ◽  
Curt J. Bougher ◽  
Grigori A. Medvedev ◽  
James Caruthers ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Chlorine Dioxide ◽  
Transfer Reaction ◽  
Water Soluble ◽  
Reaction Pathways ◽  
Mechanistic Study ◽  
Manganese Porphyrin ◽  
Oxygen Atom Transfer ◽  
On Demand ◽  
Proton Coupled Electron Transfer

A water-soluble manganese porphyrin complex was examined for the catalytic formation of chlorine dioxide from chlorite under ambient temperature at pH 5.00 and 6.90. Quantitative kinetic modeling allowed for the deduction of a mechanism that accounts for all experimental observations. Catalysis is initiated via an OAT (Oxygen Atom Transfer) reaction resulting in formation of a putative manganese(V) oxo species, which undergoes ET (Electron Transfer) with chlorite to form chlorine dioxide. As chlorine dioxide accumulates in solution, chlorite consumption slows down and ClO 2 reaches a maximum as the system reaches equilibrium. In phosphate buffer at pH 6.90, manganese(IV) oxo accumulates and its reaction with ClO 2 gives ClO 3-. However, at pH 5.00 acetate buffer proton coupled electron transfer (PCET) from chlorite to manganese(IV) oxo is fast and irreversible leading to chlorate formation only via the putative manganese(V) oxo species. These differences underscore how PCET rates affect reaction pathways and mechanism. The ClO 2 product can be collected from the aqueous reaction mixture via purging with an inert gas, allowing for the preparation of chlorine dioxide on-demand.

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