title: NMR investigation into the dynamic behaviour of a novel C2-symmetric macrocyclic ligand.
abstract: The variable-temperature (1)H NMR spectra of a tosylated triazacyclononane are reported. The spectra show a dynamic process which is assigned to hindered rotation about the amide-like N--S bonds, and a value for the free energy of activation for the rotations is derived, DeltaG* = 50.2 kJ mol(-1) at 273 K. Steric and electronic factors which influence the barrier are discussed.
authors.affiliation: Department of Chemistry, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
authors.forename: J Erik W
authors.initials: JE
authors.lastname: Scheuermann
authors.forename: Edson S
authors.initials: ES
authors.lastname: Bento
authors.forename: Geoffrey E
authors.initials: GE
authors.lastname: Hawkes
authors.forename: Michael
authors.initials: M
authors.lastname: Watkinson
mesh_terms: D006571:Heterocyclic Compounds / Q000737:chemistry; D007700:Kinetics; D008024:Ligands; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods* / Q000592:standards*; D008968:Molecular Conformation; D011522:Protons; D012015:Reference Standards; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D006571:Heterocyclic Compounds; D008024:Ligands; D047028:Macrocyclic Compounds; D011522:Protons; C075712:1,4,7-triazacyclononane