The infrared spectrum of phthalocyanine: assignment of N–H modes

Sammes, M. P.

doi:10.1039/p29720000160

Cited by 42 publications

(27 citation statements)

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“…b Obtained from [42]. c Obtained from [43]. A similar mechanism of polymeric FePc demetallation in acid medium during the orr was proposed by Meier et al [51] on the basis of 59 Fe radiotracer and Mössbauer experiments.…”

Section: Stability Of the Fepc Catalyst In Acid Mediummentioning

confidence: 73%

“…After a few minutes of chronoamperometry in O 2 -saturated acid electrolyte, the IR spectrum changed. The localisation of the main absorption bands for the last recorded spectrum are also listed in Table 2 together with results obtained by Sidorov and Kotlyar [42] and Sammes [43] for H 2 Pc. Again, the experimental data fit well.…”

Section: Stability Of the Fepc Catalyst In Acid Mediummentioning

confidence: 93%

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Oxygen reduction reaction in acid medium at iron phthalocyanine dispersed on high surface area carbon substrate: tolerance to methanol, stability and kinetics

Baranton

Coutanceau

Roux

et al. 2005

Journal of Electroanalytical Chemistry

256

164

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Section: Stability Of the Fepc Catalyst In Acid Mediummentioning

confidence: 73%

Section: Stability Of the Fepc Catalyst In Acid Mediummentioning

confidence: 93%

Oxygen reduction reaction in acid medium at iron phthalocyanine dispersed on high surface area carbon substrate: tolerance to methanol, stability and kinetics

Baranton

Coutanceau

Roux

et al. 2005

Journal of Electroanalytical Chemistry

256

164

View full text Add to dashboard Cite

“…The antisymmetric N-H stretching mode has been identified at 3290 cm À1 in KBr pellets 12 and at 3273 cm À1 in Nujol. 12 This assignment has been supported by the observation of the N-D antisymmetric stretching at 2458 cm À1 . Our matrix results also confirm this assignment with the N-H stretching mode of H 2 Pc observed in Ar (see Fig.…”

Section: Isotope Shiftsmentioning

confidence: 97%

“…While several infrared studies have been presented for H 2 Pc 11,12 and ZnPc 13 in KBr discs and in Nujol, no reports currently exist for the low temperature IR spectra of these molecules. Despite the numerous infrared studies of H 2 Pc which have been published, the assignments of several vibrational modes remain uncertain, especially in the case of the N-H In-Plane Bending (NH-IPB) mode.…”

Section: Introductionmentioning

confidence: 99%

Infra-red and Raman spectroscopy of free-base and zinc phthalocyanines isolated in matrices

Murray

Dozova

McCaffrey

et al. 2010

Phys. Chem. Chem. Phys.

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The infrared absorption spectra of matrix-isolated zinc phthalocyanine (ZnPc) and free-base phthalocyanine (H 2 Pc) have been recorded in the region from 400 to 4000 cm À1 in solid N 2 , Ar, Kr and Xe. Raman spectra have been recorded in doped KBr pellets. The isotopomers HDPc and D 2 Pc have been synthesised in an attempt to resolve the conflicting assignments that currently exist in the literature for the N-H bending modes in H 2 Pc spectra. A complete correlation between the vibrational modes of the three free-base isotopomers and ZnPc has been achieved. Comparison of the IR and Raman spectroscopic results, obtained with isotopic substitution and with predictions from large basis set ab initio calculations, allows identification of the in-plane (IP) and out-of-plane (OP) N-H bending modes. The largest IP isotope shift is observed in the IR at 1046 cm À1 and at 1026 cm À1 in Raman spectra while the largest effect in the OP bending modes is at 764 cm À1 . OP bending modes are too weak to be observed in the experimental Raman data. The antisymmetric N-H stretching mode is observed at B3310 cm À1 in low temperature solids slightly blue shifted from, but entirely consistent with the literature KBr data. With the exception of the N-H stretches, the recorded H/D isotope shifts in all the N-H vibrations are complex, with the IP bending modes exhibiting small n H /n D ratios (the largest value is 1.089) while one of the observed OP modes has a ratio o 1. DFT results reveal that the small ratios arise in particular from strong coupling of the N-H IP bending modes with IP stretching modes of C-N bonds. The unexpected finding of a n H /n D ratio smaller than one was analysed theoretically by examining the evolution of the frequencies of the free base by increasing the mass from H to D in a continuous manner. A consequence of this frequency increase in the heavier isotopomer is that the direction of the N-D OP bend is reversed from the N-H OP bend.

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“…The calculated IR vibrational modes were investigated and compared with the experimental ones for H 2 Pc [36] and other theoretical work [37] to ensure the rationality of our results. The calculated data is scaled by the factor 0.9613 that was recommended in the previous research work [38,39].…”

Section: Infrared Spectramentioning

confidence: 99%

Structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine investigated using density functional theory

Wang

Sun

et al. 2010

Sci. China Chem.

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Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculation were adopted to study the structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine (TTPPzH 2 and TTPPzMg) using B3LYP method with the 6-31G(d) basis set. A comparison of the geometrical structures, atomic charges, molecular orbitals, UV-vis spectra and infrared (IR) spectra among tetrathieno[2,3-b]porphyrazine (TTPPzH 2 ), phthalocyanine (H 2 Pc) and porphyrazine (H 2 Pz) compounds was performed. The substituent effect of the thiophene heterocycle for electron-donating on the structures and properties of these compounds has been discussed. Compared with other atoms, the charge distribution of C  atoms adjacent to the sulfur atom is significantly influenced by the thiophene heterocycle substituents. The enlargement of the HOMO-LUMO gaps from H 2 Pc and MgPc to TTPPzH 2 and TTPPzMg is at the origin of the observed blue shift of the Q band when moving from H 2 Pc to TTPPzH 2 compounds. Special emphasis has been devoted to the strongest B bands for TTPPzH 2 compounds which show red shift due to the large destabilization of the lower lying occupied orbitals compared with the corresponding B bands of H 2 Pc compounds. With the assistance of animated pictures produced on the basis of the normal coordinates, the significant peaks and vibration modes in the IR spectra of all the compounds were assigned and analyzed. tetrathieno[2,3-b]porphyrazine, DFT method, molecular structure, UV-vis spectra, IR spectra

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The infrared spectrum of phthalocyanine: assignment of N–H modes

Cited by 42 publications

References 0 publications

Oxygen reduction reaction in acid medium at iron phthalocyanine dispersed on high surface area carbon substrate: tolerance to methanol, stability and kinetics

Oxygen reduction reaction in acid medium at iron phthalocyanine dispersed on high surface area carbon substrate: tolerance to methanol, stability and kinetics

Infra-red and Raman spectroscopy of free-base and zinc phthalocyanines isolated in matrices

Structures and properties of metal-free and magnesium tetrathieno[2,3-b]porphyrazine investigated using density functional theory

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