Electronic spectra, resonance raman spectra and solution properties of water-soluble Cu(II), Ni(II) and Co(III) porphyrins

Bütje, K.; Nakamoto, Kazuo

doi:10.1016/s0020-1693(00)83942-0

Cited by 28 publications

(23 citation statements)

References 35 publications

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“…56 Because of the binding of copper by the porphyrin ligand and the symmetry change from D 2h to D 4h the spectrum of CuTAPP exhibits only one main Q-band maximum at λ ) 539 nm (not shown). This observation in combination with hypochromicity in comparison to TAPP is consistent with the literature 57 and thus proves that TAPP is completely transformed into CuTAPP.…”

Section: Methodsmentioning

confidence: 99%

“…All TAPP and CuTAPP concentrations were calibrated from literature extinction coefficients using ε(TAPP) ) 4.16 × 10 5 M -1 cm -1 and ε(CuTAPP) ) 3.46 × 10 5 M -1 cm -1 at λ ) 412 nm. 56 Cylindrical Polystyrenesulfonate Brushes. A polystyrene macromonomer was synthesized by anionic polymerization of styrene and subsequent end-functionalization by p-vinylbenzyl chloride.…”

Section: Methodsmentioning

confidence: 99%

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Finite-Size Networks from Cylindrical Polyelectrolyte Brushes and Porphyrins

Ruthard

Maskos²,

Kolb³

et al. 2009

Macromolecules

114

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We report on the electrostatic self-assembly of negatively charged cylindrical polystyrenesulfonate (NaPSS) brushes and stiff organic counterions of different valency. In particular, the tetravalent cationic porphyrin meso-tetrakis(4-(trimethylammonium)phenyl)porphyrin (TAPP) yielded two new supramolecular architectures that are stable in aqueous solution. The porphyrin binds to the polyelectrolyte brush due to electrostatic and secondary π-π interactions and can further interconnect the brushes to nanoscale networks. In salt solution individual porphyrin-decorated cylindrical brushes were obtained. Structures formed are characterized by UV-vis spectroscopy, atomic force microscopy (AFM), cryo-transmission electron microscopy (cryo-TEM), small-angle neutron scattering (SANS), and dynamic light scattering (DLS). In order to study porphyrin aggregates by DLS, an IR laser setup (λ ) 831.5 nm) was used. The new morphologies have potential as functional structures in molecular electronics and pharmaceutics.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Finite-Size Networks from Cylindrical Polyelectrolyte Brushes and Porphyrins

Ruthard

Maskos²,

Kolb³

et al. 2009

Macromolecules

114

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“…35 -43 Surprisingly, RR data for water-soluble Co(II) porphyrins have not yet been reported in the literature; their aqueous solutions are very unstable owing to their sensitivity to molecular oxygen dissolved in water. For Co(III) derivatives of watersoluble porphyrins, RR spectra have been published, 10,44,45 but spectroscopic characterization of their ligated species has not been carried out.…”

Section: Introductionmentioning

confidence: 99%

Resonance Raman characterization of cationic Co(II) and Co(III) tetrakis(N‐methyl‐4‐pyridinyl)porphyrins in aqueous and non‐aqueous media

Терехов

Kruglik

Malinovskii

et al. 2003

J Raman Spectroscopy

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Resonance Raman (RR) spectra of Co(II) and Co(III) complexes of the water-soluble cationic tetrakis(Nmethyl-4-pyridinyl)porphyrin [Co II TMpyP(4), Co III TMpyP (4)] were obtained in aqueous and non-aqueous media, using both B-and Q-band excitation wavelengths. RR spectra of Co II TMpyP(4) are observed for the first time, and they are compared with those of Co III TMpyP(4). Wavenumbers of the n 2 , n 4 , n 8 and n 6 oxidation state-sensitive bands depend on pH in aqueous solution and on the nature of the solvent ( methanol, ethanol, DMF, DMSO): they lie in distinct spectral ranges for Co(II) vs Co(III) porphyrins. In addition, wavenumber shifts induced by axial ligation cover regions twofold broader for Co III TMpyP(4) than for Co II TMpyP(4). This shows that the electronic influence of axial ligands on the p-system of the macrocycle is more effective when cobalt is in a higher oxidation state. This can be due to (i) smaller axial bond lengths of Co(III) porphyrin and, hence, more efficient cobalt-axial ligand interaction as compared with Co(II) complexes, and (ii) Co III TMpyP(4) being involved in bis-adducts whereas Co II TMpyP(4) ismainly bound with only one axial ligand. The response of the porphyrin ring to the binding of axial ligands having various electron-donating-withdrawing properties was monitored by the behaviour of these oxidation-state sensitive RR bands: their shifts observed in a series of solvents were compared with Gutmann donor and acceptor numbers (DN, AN) of the solvents. A linear positive correlation was observed between Gutmann AN and n 2 , n 4 , n 8 and n 6 band wavenumbers for Co III TMpyP(4), whereas a linear negative correlation was observed for the same bands of Co II TMpyP(4) when DN increases. This means that enhanced electron-accepting properties of axial ligand result in a scarcity of cobalt d p -orbitals, which in turn leads to a decrease in p back-donation from cobalt to the porphyrin macrocycle.

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“…[59,60] Surprisingly, the strong relative enhancement of the 1638 cm −1 band might be thus explained by the enhancement mechanism of the SERS, [61 -63] taking into account the orientation of the porphyrin macrocycle relative the silver surface. The analysis of SERS spectra with regard to the orientation of the analyte is based on the surface selection rules founded on the electromagnetic theory of SERS intensities.…”

Section: Relative Enhancement Factors For Raman Bands Of Zntmpyp4mentioning

confidence: 99%

A comparative study of surface‐enhanced Raman scattering from silver‐coated anodic aluminum oxide and porous silicon

Терехов

Mojzeš

Kachan

et al. 2011

J Raman Spectroscopy

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International audienceThree types of Ag-coated arrays from porous anodic aluminum oxide (AAO) were prepared and studied as substrates for surface-enhanced Raman scattering (SERS). They were compared with Ag-coated porous silicon (PSi) samples. AAO-based substrates were prepared by the vapor deposition of silver directly onto the surface of porous AAO with different morphologies of the pores, whereas SERS-active island films on the PSi were prepared by immersion plating. The resulting metallic nanostructures were characterized by UV-vis absorption spectroscopy and scanning electron microscopy (SEM). Thermal evaporation leads to the formation of granular arrays of Ag nanoparticles on the surface of AAO. SERS activity of the substrates was tested using water-soluble cationic Zn(II)-tetrakis (4-N-methylpyridyl) porphyrin (ZnTMPyP4) as a probe molecule. The results indicate that all AAO-based substrates studied here exhibit some degree of SERS activity. Noteworthy, for excitation at 532 nm, signals from AAO-based substrates were comparable with those from the PSi-based ones, whereas for 441.6 nm excitation they were about twice higher. The strongest SERS- enhancement at 441.6 nm excitationwas provided by the AAO substrates with silver deposited on the monolith (originally nonporous) side of AAO. Preferential SERS-enhancement of the bands ascribed to the vibrations of the N-methylpyridinium group of ZnTMPyP4 when going to blue excitation was found

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Electronic spectra, resonance raman spectra and solution properties of water-soluble Cu(II), Ni(II) and Co(III) porphyrins

Cited by 28 publications

References 35 publications

Finite-Size Networks from Cylindrical Polyelectrolyte Brushes and Porphyrins

Finite-Size Networks from Cylindrical Polyelectrolyte Brushes and Porphyrins

Resonance Raman characterization of cationic Co(II) and Co(III) tetrakis(N‐methyl‐4‐pyridinyl)porphyrins in aqueous and non‐aqueous media

A comparative study of surface‐enhanced Raman scattering from silver‐coated anodic aluminum oxide and porous silicon

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