Identification of the tautomeric structure of H2TMpyP4–DNA complexes from resonance Raman excitation profiles

1992 ◽  
Vol 70 (9) ◽  
pp. 2413-2419
Author(s):  
Liu Yixian ◽  
J. A. Koningstein ◽  
Y. Yevdokimov
Keyword(s):  
Resonance Raman ◽  
Normal Modes ◽  
Raman Intensity ◽  
Absorption Region ◽  
Buffer Solutions ◽  
Bending Mode ◽  
Resonance Raman Spectra ◽  
Raman Excitation Profiles ◽  
Dna Complex ◽  
Soret Absorption

Aspects of the electronic structure of tautomers of tetrakis(N-methyl-4-pyridyl)porphyrin (H2TMpyP4) complexed to DNA have been determined from a study of the resonance Raman excitation profiles of normal modes of H2TMpyP4 in buffer solutions containing monomeric and aggregated molecules and of a H2TMpyP4/DNA complex with r(c) ~ 25. Maxima of the excitation profiles of the complex have been assigned to electronic origins for transitions between the ground state and states in the Soret absorption region of intercalated and externally groove-bound tautomers of H2TMpyP4. The positions of the electronic origins support the assignment of the CD spectrum of the complex. From the shift of the Cβ—H bending mode of the selectively excited resonance Raman spectra of tautomers of the porphyrin molecules it can be concluded that the pyridyl rings of externally bound H2TMpyP4 molecules are twisted to a lesser degree than those rings for intercalated H2TMpyP4. Raman intensity studies also reveal that the resonance-enhanced Raman intensity of modes of aggregated H2TMpyP4 is greater than those of the monomer.

The infrared, Raman, and resonance Raman spectra and normal coordinate analysis of methyl and ethyl dithioacetate

1982 ◽  
Vol 60 (2) ◽  
pp. 174-189 ◽  
Author(s):  
J. J. C. Teixeira-Dias ◽  
V. M. Jardim-Barreto ◽  
Y. Ozaki ◽  
A. C. Storer ◽  
P. R. Carey
Keyword(s):  
Raman Spectra ◽  
Vibrational Spectra ◽  
Resonance Raman ◽  
Normal Coordinate Analysis ◽  
Raman Intensity ◽  
Normal Coordinate ◽  
Intensity Enhancement ◽  
Strong Intensity ◽  
Resonance Raman Spectra ◽  
Absorbance Peak

Infrared, Raman, and resonance Raman data are reported for ethyl and methyl dithioacetate together with data for their isotopically substituted analogs: CD3C(=S)SCH3, CH3C(=S)SCD3, 13CH3C(=S)SCH3, CH313C(=S)SCH3, CD3C(=S)SCH2CH3, CH3C(=S)SCD2CH3, and CH313C(=S)SCH2CH3. Based on these data and a normal coordinate analysis of methyl dithioacetate, assignments are proposed for the majority of bands appearing in the vibrational spectra. Using excitation wavelengths in the 324–356 nm region strong intensity enhancement is observed for Raman bands near 1195, 1100, 730, and 580 cm−1 which are assigned to stretching motions of the CCSSC skeleton. Raman excitation profiles are reported for the 1197 and 581 cm−1 bands of ethyl dithioacetate and the electronic absorbance peak near 305 nm is identified as the source of resonance Raman intensity enhancement.

Resonance Raman in platinum phthalocyanine

1978 ◽  
Vol 56 (7) ◽  
pp. 976-984 ◽  
Author(s):  
Tzer-Hsiang Huang ◽  
Klaus E. Rieckhoff ◽  
Eva-Maria Voigt
Keyword(s):  
Absorption Maximum ◽  
Lower Energy ◽  
Mixed Solvents ◽  
Resonance Raman ◽  
Visible Region ◽  
Excited Singlet ◽  
Absorption Region ◽  
The Third ◽  
Resonance Raman Spectra ◽  
Platinum Phthalocyanine

The resonance Raman spectra and excitation profiles of platinum phthalocyanine (PtPc) in α-chloronaphthalene (α-ClN) and in mixtures of α-ClN and n-octane were obtained at 295 K with excitation from 660 to 570 nm covering the total lower energy absorption region of PtPc. Eighteen fundamentals and overtone-combinations were observed. Our data show that the third absorption maximum of PtPc in the visible region is actually the (0–1), but not the (0–2) as previously interpreted, transition. The (0–1) bands in the excitation profiles of most resonance-enhanced-vibrations were found to be more intense and frequency shifted compared with their counterparts in absorption. Based on the depolarization ratios, we deduced the symmetry of PtPc in α-ClN in the excited singlets to be D2h, C2v, or D2; no differences were found in the mixed solvents. The small Stokes loss observed in the absorption spectra, as well as the absence of the (0–2) maxima in the excitation profiles, indicate that the equilibrium position of the first excited singlet is only slightly different from that of the ground state.

Resonance Raman spectra and normal modes of vibration of 2,2′-bipyridine anion radicals

1990 ◽  
Vol 21 (1) ◽  
pp. 3-8 ◽  
Author(s):  
Gerald D. Danzer ◽  
Janusz A. Golus ◽  
Dennis P. Strommen ◽  
James R. Kincaid
Keyword(s):  
Raman Spectra ◽  
Resonance Raman ◽  
Normal Modes ◽  
Modes Of Vibration ◽  
Resonance Raman Spectra ◽  
Anion Radicals
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