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Nuclear spin relaxation in some phenyl phosphorus compounds
- Source :
- Spectrochimica Acta Part A: Molecular Spectroscopy. 45:1257-1262
- Publication Year :
- 1989
- Publisher :
- Elsevier BV, 1989.
-
Abstract
- 13 C and 31 P spin-lattice relaxation times ( T 1) and nuclear Overhauser effects were measured in triphenylphosphine, triphenylphosphine oxide, triphenylphosphine sulphide, and triphenylphosphine selenide, over a temperature, range −40°C to +55°C. Isotropic reorientation correlation times were calculated from the dipolar relaxation times for phosphorus and that for the para carbon. The spin-rotation mechanism is the dominant relaxation mechanism for phosphorus in triphenylphosphine, whereas the chemical shift anisotropy is the dominant mechanism in triphenylphosphine oxide at low temperatures. In triphenylphosphine sulphide and triphenylphosphine selenide, the dipolar and the chemical shift anisotropy mechanisms are important in phosphorus relaxation. The motional anisotropy of internal rotation of phenyl rings and overall tumbling is determined from the ratio of T 1 's of ortho or meta carbon to para carbon, and is found to increase with the decrease in temperature and with the increase in mol. wt. The angular momentum correlation times were calculated from phosphorus spin-rotation relaxation rates. From viscosity data, reduced correlation times were calculated and compared with that calculated using Stokes-Einstein-Debye, Gierer-Wirtz, and Hu-Zwanzig models.
- Subjects :
- Phosphorus
Relaxation (NMR)
General Engineering
Spin–lattice relaxation
chemistry.chemical_element
Triphenylphosphine selenide
Nuclear Overhauser effect
Condensed Matter::Materials Science
chemistry.chemical_compound
Nuclear magnetic resonance
chemistry
Physical chemistry
Physics::Chemical Physics
Triphenylphosphine
Anisotropy
Triphenylphosphine oxide
Subjects
Details
- ISSN :
- 05848539
- Volume :
- 45
- Database :
- OpenAIRE
- Journal :
- Spectrochimica Acta Part A: Molecular Spectroscopy
- Accession number :
- edsair.doi...........29d94a7f911f1515c1d7d40469c28e1a