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Title Resonance Raman vibrational analysis of Cu sup II , Fe sup III , and Co sup III porphyrin ..pi.. cation radicals and their meso-deuteriated analogues
Creator/Author Oertling, W.A. ; Salehi, A. ; Chang, C.K. ; Babcock, G.T. (Michigan State Univ., East Lansing (USA))
Publication Date1989 Feb 23
OSTI IdentifierOSTI ID: 5112543
Other Number(s)ISSN0022-3654; CODEN: JPCHA
Resource TypeJournal Article
Resource RelationJournal of Physical Chemistry ; Vol/Issue: 93:4
Subject400201 -- Chemical & Physicochemical Properties ;140505 -- Solar Energy Conversion-- Photochemical, Photobiological, & Thermochemical Conversion-- (1980-); COBALT COMPLEXES-- VIBRATIONAL STATES;COPPER COMPLEXES-- VIBRATIONAL STATES;DEUTERIUM COMPOUNDS-- VIBRATIONAL STATES;IRON COMPLEXES-- VIBRATIONAL STATES;PORPHYRINS-- VIBRATIONAL STATES; CATIONS;EXPERIMENTAL DATA;ISOTOPE EFFECTS;NORMAL-MODE ANALYSIS;RADICALS;RAMAN SPECTROSCOPY;RESONANCE SCATTERING;SPECTRAL SHIFT
Related SubjectCARBOXYLIC ACIDS;CHARGED PARTICLES;COMPLEXES;DATA;ENERGY LEVELS;EXCITED STATES;HETEROCYCLIC ACIDS;HETEROCYCLIC COMPOUNDS;HYDROGEN COMPOUNDS;INELASTIC SCATTERING;INFORMATION;IONS;LASER SPECTROSCOPY;NUMERICAL DATA;ORGANIC ACIDS;ORGANIC COMPOUNDS;ORGANIC NITROGEN COMPOUNDS;SCATTERING;SPECTROSCOPY;TRANSITION ELEMENT COMPLEXES
Description/Abstract Analysis of the near-UV resonance Raman enhanced vibrations in the 1000-1700-cm{sup {minus}1} range of Cu{sup II}, Fe{sup III}, and Co{sup III} complexes of octaethylporphyrin and etioporphyrin I {pi} cation radicals and of the corresponding complexes with {sup 2}H substituted at the porphyrin methine carbon positions is presented.^Comparison of analogous spectra of octaethylporphyrin vs etioporphyrin I complexes is used to identify vibrations involving the pyrrole b-carbon atoms and thus serves as an alternative to isotopic labeling at this position.^The results are consistent with and provide an extension of our earlier vibrational assignments, which were based on structural trends and depolarization ratios of the Raman bands in the 1450-1700-cm{sup {minus}1} region.^Our results reveal that the wavenumbers of the octaethylporphyrin C{sub a}C{sub m}, C{sub a}N, and C{sub a}C{sub b} internal stretching coordinates decrease slightly while those of the C{sub b}C{sub b} stretching coordinates increase when the macrocycle is oxidized by one electron.^The magnitude of the wavenumber shifts caused by methine carbon deuteriation and b-carbon substitution are comparable for the neutral and {pi} cation species.^This suggests that although the force constants are changed ({approx}1-3%) upon oxidation, the overall potential energy distributions of the normal coordinates of the {pi} cation radical remain similar to those of the parent compounds, most likely reflecting similar macrocycle stereochemistry for neutral and oxidized species in CH{sub 2}Cl{sub 2} solution.^Our analysis suggests that the optical and resonance Raman spectral properties of these complexes strongly reflect the conformation of the oxidized porphyrin ring.^This implies that the distinct optical spectra of the cobaltic octaethylporphyrin {pi} cations.
Country of PublicationUnited States
LanguageEnglish
FormatPages: 1311-1319
System Entry Date2001 May 13

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