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Molecular factors that determine Curie spin relaxation in dysprosium complexes †
Author(s) -
Caravan P.,
Greenfield M.T.,
Bulte J.W.M.
Publication year - 2001
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.1277
Subject(s) - dysprosium , chemistry , relaxation (psychology) , curie temperature , coordination sphere , proton , curie , dipole , nuclear magnetic resonance , spin crossover , crystallography , condensed matter physics , inorganic chemistry , ferromagnetism , physics , psychology , social psychology , organic chemistry , quantum mechanics , crystal structure
Dysprosium complexes can serve as transverse relaxation ( T 2 ) agents for water protons through chemical exchange and the Curie spin relaxation mechanism. Using a pair of matched dysprosium(III) complexes, Dy‐L1 (contains one inner‐sphere water) and Dy‐L2 (no inner‐sphere water), it is shown that the transverse relaxation of bulk water is predominantly an inner‐sphere effect. The kinetics of water exchange at Dy‐L1 were determined by 17 O NMR. Proton transverse relaxation by Dy‐L1 at high fields is governed primarily through a large chemical shift difference between free and bound water. Dy‐L1 forms a noncovalent adduct with human serum albumin which dramatically lengthens the rotational correlation time, τ R , causing the dipole–dipole component of the Curie spin mechanism to become significant and transverse relaxivity to increase by 3–8 times that of the unbound chelate. These findings aid in the design of new molecular species as efficient r 2 agents. Magn Reson Med 46:917–922, 2001. Published 2001 Wiley‐Liss, Inc.