REVERSION OF MAGNETIC-FIELD EFFECTS UNDER LARGE MAGNETIC-FIELDS OBSERVED IN THE PHOTOCHEMICAL HYDROGEN ABSTRACTION REACTIONS OF FLUORINATED ACETOPHENONE AND BENZOPHENONE IN MICELLAR SOLUTIONS

被引：14

作者：

IGARASHI, M

MENG, QX

SAKAGUCHI, Y

HAYASHI, H

机构：

[1] Molecular Photochemistry Laboratory, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama

来源：

MOLECULAR PHYSICS | 1995年 / 84卷 / 05期

关键词：

D O I：

10.1080/00268979500100651

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Magnetic field effects (MFEs) on the dynamic behaviour of radical pairs generated by the photochemical hydrogen abstractions of 2', 3', 4', 5', 6'-pentafluoroacetophenone and decafluorobenzophenone in micellar solutions were investigated at large magnetic fields up to 10 T using a superconducting magnet. These MFEs were compared with the MFEs observed in the reactions of acetophenone and benzophenone. The decay rate of a radical pair generated in the reaction of acetophenone in a Brij 35 micellar solution decreased with increasing magnetic flux density (B) from 0 T, and the decrease was saturated at 0.34 T. On the other hand, the decay rate of the pair in the reaction of pentafluoroacetophenone decreased steeply with increasing B from 0 to 2 T, but increased gradually from 2 to 10 T. Such reversions of MFEs were observed for benzophenone and decafluorobenzophenone in Brij 35 micellar solutions, and the degree of the reversion for decafluorobenzophenone was larger than that of benzophenone. These new reverted MFEs were explained in terms of the relaxation mechanism. The reverted MFEs can be observed when the escape rate of a radical from a radical pair is much slower than the electron spin relaxation rates.

引用

页码：943 / 955

页数：13

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