Photorearrangement in a Semiquinone to Yield an Unusual 1,3-Carbon/Carbon Interaction and Spin Delocalization

Autor:	Yong Seol Kim, Cheryl D. Stevenson
Rok vydání:	1999
Předmět:	Semiquinone Hydrogen bond Photochemistry Photoinduced electron transfer law.invention chemistry.chemical_compound chemistry Hexamethylphosphoramide law Alkoxy group Moiety Physical and Theoretical Chemistry Electron paramagnetic resonance Tetrahydrofuran
Zdroj:	The Journal of Physical Chemistry A. 103:7139-7141
ISSN:	1520-5215 1089-5639
DOI:	10.1021/jp9912408
Popis:	Solutions of 1,4-bis(dihydroquininyl)-anthraquinone {(DHQ)2AQN} in either hexamethylphosphoramide (HMPA) or liquid ammonia undergo a photoinduced electron transfer from the solvent to the (DHQ)2AQN. The resulting anion radical {(DHQ)2AQN•-} yields coupling to the six (3 sets of 2 equivalent) protons on the anthraquinone moiety upon EPR analysis. The same anion radical can be generated via alkali metal reduction in tetrahydrofuran. Further exposure of the HMPA solution to visible light causes the anion radical to undergo a conformational change. The photorearranged product allows delocalization of spin into the γ proton on the sp3 hybridized alkoxy carbon. In NH3(liq) and THF, hydrogen bonding and ion association prevents this photorearrangement, respectively.
Databáze:	OpenAIRE
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