Spin-lattice relaxation, nuclear Overhauser enhancements, and long range coupling in chlorophylls and metalloporphyrins
- 1 January 1978
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 1
- No. 10,p. 1150-1157
- https://doi.org/10.1039/p19780001150
Abstract
Methyl groups in the title series have proton spin-lattice relaxation times (T1) which depend largely on the distance of the group from the macrocycle and their steric crowding whereas T1 values for meso-protons are dependent on substitution pattern. Nuclear Overhauser enhancements and long-range coupling constants can be used to construct connectivities around the macrocycle. Together, these techniques provide unambiguous assignments of resonances and structures. Systematic linewidth variations are due to predictable contributions from unresolved couplings, short T1 and electron-transfer effects. A non-seasonal preparation of methyl chlorophyllides is described.This publication has 4 references indexed in Scilit:
- Structural and mode of action studies on the antibiotic vancomycin. Evidence from 270-MHz proton magnetic resonanceJournal of the American Chemical Society, 1977
- The NMR spectra of porphyrins—12Tetrahedron, 1977
- Mechanisms of aggregation in metalloporphyrins: demonstration of a mechanistic dichotomyJournal of the Chemical Society, Chemical Communications, 1976
- The chlorophyll-a radical-cation: determination of hyperfine coupling constants by nuclear magnetic resonance spectroscopyJournal of the Chemical Society, Chemical Communications, 1976