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Solvation of alkylaromatic hydrocarbons towards a paramagnetic relaxation reagent, tris(acetylacetonato)chromium(III)
Author(s) -
Holak Tadeusz A.,
Aksnes Dagfinn W.,
Grahn Hans,
Edlund Ulf
Publication year - 1986
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/mrc.1260240704
Subject(s) - chemistry , paramagnetism , chromium , reagent , relaxation (psychology) , rotational diffusion , solvation , tris , dipole , spin–lattice relaxation , nuclear magnetic resonance , photochemistry , crystallography , organic chemistry , ion , molecule , condensed matter physics , psychology , social psychology , biochemistry , physics
A 13 C electron–nuclear spin–lattice relaxation study showed that the interaction between alkyl‐substituted aromatics and a paramagnetic relaxation reagent, tris(acetylacetonato)chromium(III), is purely electrostatic, i.e. of a dipole–dipole or dipole–induced dipole type. Except for aromatics having bulky alkyl groups, the preferred chelate position is close to the positive end of the dipole, i.e. close to the α‐position. However, the major electron–nuclear mechanism is non‐specific, and the relaxation rate is mainly controlled by the mutual translational/rotational diffusion of the two species. Paramagnetic shifts induced on addition of Cr(acac) 3 support the suggested interaction mechanism.