ISSN:
0377-0486
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Resonance Raman (RR) spectra obtained with several excitation wavelengths are compared for the following porphyrin-IX compounds: free-base protoporphyrin-IX, meso-porphyrin-IX and haematoporphyrin-IX and copper-protoporphyrin-IX and copper-mesoporphyrin-IX dimethyl esters. Certain bands in the RR spectra of all the free-base porphyrins or copper complexes are unaffected with respect to frequency, whereas there is a shift in the frequencies of some vibrational modes in some systems. From a comparative study of the systems which have identical geometrical arrangements, no extra features were found in the RR spectra of protoporphyrin which can be attributed directly to the vinyl group modes. This suggests that the vibrational modes of vinyl groups do not distort the excited electronic state substantially, and are not effective in vibronic coupling with the electronic states of the porphyrin macrocycle and therefore do not gain intensity under resonance excitation. Most of the vibrational modes are strongly coupled and there are no extra distinct features in the RR spectra of PP which may be associated with selective vibrational coupling of the vinyl group modes with the porphyrin skeletal modes.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jrs.1250170506
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