1H-NMR studies on the self-association of chloroquine in aqueous solution.
The concentration dependences of 1H-NMR chemical shifts and spin-lattice relaxation rates were measured for chloroquine in aqueous solution. The weak self-association constant was evaluated according to a dimerization equilibrium with the formation of self-stacked adducts (Kd = 4.52 +/- 0.68 l mol-1). The motional correlation times were evaluated for the monomer and the dimer by measuring intramolecular dipolar cross-relaxation rates of aromatic vicinal protons (tau cm = 0.06 ns and tau cd = 0.26 ns). The geometry of the stacked dimer was elucidated by measuring intermolecular dipolar cross-relaxation rates and interpreted in terms of partial superposition of quinoline moieties.
Department of Chemistry, University of Siena, Italy.
N
N
Marchettini
G
G
Valensin
E
E
Gaggelli
D002738:Chloroquine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation
D002738:Chloroquine