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ESR measurements of the partitioning of some new spin probes in n ‐octanol–water
Author(s) -
Bottle Steven E.,
Gillies Duncan G.,
Micallef Aaron S.,
Reid Damien A.,
Sutcliffe Leslie H.
Publication year - 1999
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/(sici)1097-458x(199910)37:10<730::aid-mrc530>3.0.co;2-e
Subject(s) - chemistry , spin probe , hyperfine structure , octanol , polar , analytical chemistry (journal) , spin (aerodynamics) , partition coefficient , organic chemistry , thermodynamics , atomic physics , membrane , biochemistry , physics , astronomy
The stable free radical 1,1,3,3‐tetramethylisoindolin‐2‐yloxyl (TMIO) has proved to be very suitable for use as a spin probe for a number of applications. Because it is soluble mainly in non‐polar liquids, there is a need for new derivatives that can be used in a variety of environments. This has been done by introducing substituents in the 5‐position of the aromatic ring, namely carboxyl (CTMIO), trimethylamino (TMTMIOI) and sodium sulphonate (NaTMIOS). An accurate ESR method was developed for the measurement of partition coefficients in n ‐octanol–water. For comparison purposes the method was also applied to some Tempo derivatives. The effect of temperature on the rotational correlation times and the nitrogen‐14 hyperfine coupling constant of some of the spin probes was investigated. There is evidence for dimerization of CTMIO to form a biradical. Copyright © 1999 John Wiley & Sons, Ltd.