ISSN:
0749-1581
Keywords:
1H NMR
;
13C NMR
;
Chlorophyll
;
Chlorin
;
Porphyrin
;
Tetrapyrrole
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The 1H and 13C NMR spectra of 132(R)-methoxychlorophyll a were assigned utilizing the two-dimensional 1H-detected heteronuclear one-bond (HMQC) and multiple-bond (HMBC) correlation techniques. The protons and carbons of the macrocycle and its short side-chains could be completely assigned using the HMQC and HMBC data in concert. These techniques were also valuable in achieving assignments for the phytyl chain, which were previously incomplete. The proton and carbon assignments of the P1-CH2, P2-CH, P4-CH2 and P15-CH groups and those of all methyl groups of the phytyl chain could be established by the coupling patterns and by the combined information obtained from the HMQC and HMBC connectivities. Fairly unambiguous proton and carbon assignments were also obtained for the P6-CH2, P7-CH, P9-CH2, P11-CH and P14-CH2 groups. The sensitivity of the HMQC and HMBC techniques is good, making it possible to achieve the spectral assignments under high dilution and monomeric conditions. This was considered to be of paramount importance in the structural analysis of chlorophylls and related compounds, which are difficult to prepare in adequate amounts and purity because of their lability and which show a strong aggregation tendency at higher concentrations and lower temperatures.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260320107
Permalink