title: Long-lived nuclear spin states in the solution NMR of four-spin systems.
abstract: The existence of long-lived nuclear spin states in four-spin systems is explored by solution-state NMR experiments. Long-lived states are proved to exist in three different natural product molecules, each containing either a AA'BB' or a AA'XX' proton spin system. The measured state lifetimes are between four and eight times the spin-lattice relaxation time constants.
authors.affiliation: Department of Chemistry, University of Calabria, via P. Bucci, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pileio
authors.forename: Maria
authors.initials: M
authors.lastname: Concistrè
authors.forename: Marina
authors.initials: M
authors.lastname: Carravetta
authors.forename: Malcolm H
authors.initials: MH
authors.lastname: Levitt
mesh_terms: D010129:4-Aminobenzoic Acid / Q000737:chemistry*; D019343:Citric Acid / Q000737:chemistry*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D010226:Parabens / Q000737:chemistry*
chemical_list: D010226:Parabens; D019343:Citric Acid; C038193:4-hydroxybenzoic acid; D010129:4-Aminobenzoic Acid