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Natural‐abundance lithium‐6 NMR spin–lattice relaxation in some simple organolithium compounds
Author(s) -
Wehrli F. W.
Publication year - 1978
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270110210
Subject(s) - methyllithium , phenyllithium , chemistry , isotopes of lithium , relaxation (psychology) , lithium (medication) , spins , dipole , arrhenius equation , intramolecular force , spin–lattice relaxation , nuclear magnetic resonance , stereochemistry , physics , condensed matter physics , organic chemistry , activation energy , ion , medicine , social psychology , psychology , nuclear quadrupole resonance , endocrinology , ion exchange
6 Li, 7 Li and 13 C spin–lattice relaxation and NOE data are reported for methyllithium, butyllithium and phenyllithium with 6 Li T 1 values found in the order of tens of seconds and their relaxation 2–3 orders of magnitude less efficient than that for 7 Li. The data indicate that 6 Li is substantially relaxed by the intramolecular 6 Li– 1 H mechanism, whereas both quadrupolar and 6 Li– 7 Li dipolar relaxation are minor processes. The non‐linearity of the Arrhenius curve for Me 6 Li is compatible with a small spin–rotation contribution. Since 6 Li in solution behaves essentially as a spin‐1/2 nucleus, it represents, in spite of its lower magnetic moment and overall sensitivity, an attractive alternative to 7 Li NMR.