Molecular motion in some radiolabelled dipeptides: a muon spin relaxation study
β Scribed by Christopher J. Rhodes; Timothy C. Dintinger; Harry Morris; Christopher A. Scott
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 87 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.1030
No coin nor oath required. For personal study only.
β¦ Synopsis
Activation parameters were determined for the dynamics of radicals formed by muonium addition to glycylglycine (GlyGly; H 3 N + CH 2 CONHCH 2 CO - 2 ) and the doubly protected alanylalanine derivative [Boc-AlaAla-Bz; Bu t OCONHCH(Me)CONHCH(Me)CO -O -CH 2 Ph]. GlyGly forms an adduct by muonium addition to the amide carbonyl group which isomerizes by flipping the muon between opposite sides of the molecule, requiring an activation energy of 20.4 kJ mol -1 . In Boc-AlaAla-Bz, muonium addition to the benzene ring of the benzyl ( -CH 2 Ph) group occurs, exhibiting an activation energy of 9.4 kJ mol -1 , believed to be from torsion about the C -Ph bond.
π SIMILAR VOLUMES
The direct measurement of reorientational rates for hydrocarbon radicals in zeolites is presented, specifically cyclohexadienyl in zeolite X, using a muon spin relaxation method. The method allows discrimination between different adsorption sites and the determination of activation energies for surf
13C NMR spinΓlattice relaxation and 13CΓM1HN nuclear Overhauser measurements were performed on the encapsulation complex between [2.2]paracyclophane and a dimeric capsule known as the hydroxy "softball.Γ The data were analyzed using the formalism for an isotropically di β using sphere. The binding co