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Relaxivity enhancement of low molecular weight nitroxide stable free radicals: Importance of structure and medium
Author(s) -
Vallet Patrick,
van Haverbeke Yves,
Bonnet Pierre Antoine,
Subra Guy,
Chapat JeanPierre,
Muller Robert N.
Publication year - 1994
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910320103
Subject(s) - nitroxide mediated radical polymerization , paramagnetism , chemistry , molecule , relaxation (psychology) , population , adsorption , nuclear magnetic resonance , radical , hydrogen bond , dispersion (optics) , chemical physics , polymer , organic chemistry , condensed matter physics , psychology , social psychology , optics , physics , demography , radical polymerization , sociology , copolymer
Abstract The longitudinal relaxivities of seven water‐soluble nitroxide derivatives ot low‐molecular weight have been measured at 5°C and 37°C in water and in serum between 0.01 and 200 MHz. The nuclear magnetic relaxation dispersion (NMRD) profiles show a clear relationship between the relaxivity observed in serum and the relative balance of the hydrophobichydrophilic character of the paramagnetic molecules. From the data analysis, contributions arising from a population of nitroxides characterized by reduced mobility can be extracted. The values of the correlation times are consistent with a system involving nitroxides adsorbed at the surface of albumin and magnetically interacting with the protons of hydrogen bonded water molecules.