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NMR spectra of carotenoporphyrins. Computer‐assisted conformational analysis
Author(s) -
Chachaty Claude,
Gust Devens,
Moore Thomas A.,
Nemeth Gregory A.,
Liddell Paul A.,
Moore Ana L.
Publication year - 1984
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270220109
Subject(s) - porphyrin , ring (chemistry) , molecule , chemistry , side chain , nmr spectra database , proton nmr , small molecule , chemical shift , computational chemistry , stereochemistry , spectral line , photochemistry , organic chemistry , physics , biochemistry , polymer , astronomy
A computer‐assisted method of conformational analysis for porphyrin molecules bearing flexible side‐chains has been developed. The method utilizes the ring current‐induced chemical shift changes of the side‐chain protons which arise from the porphyrin macrocycle and any attached aryl rings. The treatment has been applied to a series of carotenoporphyrin molecules, which are important as models for a variety of photophysical processes in biological systems. Chemical shift data of sufficient accuracy for the conformational analysis were obtained from 500 MHz NMR experiments. The conformations of the carotenoporphyrins varied from extended ones with the carotenoid well away from the porphyrin ring to tightly folded species, depending on molecular constitution. The analytical method can be extended to other porphyrin‐based systems.