Reactivity of Unsubstituted Porphin

Schlözer, Rüdiger; Fuhrhop, Jürgen‐Hinrich

doi:10.1002/anie.197503631

Cited by 26 publications

(12 citation statements)

References 6 publications

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“…♣ E(ox1)1/2 = + 0.68 V vs. SCE 10 in similar conditions as ours. ♦ E(ox1)1/2 -E(red1)1/2 = + 2.1 V in reference 11 . 75 ♪ A complete and exhaustive study of this intriguing oxidative polymerisation as well as the characterisation of the resulting material will be soon reported.…”

Section: Notes and Referencesmentioning

confidence: 97%

“…Indeed, for 1, only the first oxidation potential and the experimental HOMO-LUMO gap (potential difference between the first oxidation and reduction) have been briefly mentioned. [9][10][11] The presence of the magnesium(II) ion in the 60 porphine cavity is of particular interest in electrochemistry since magnesium insertion is known to drastically reduce the porphyrin redox potentials compared to free bases, providing an easier access to the oxidised states. 12 Bearing in mind that, when oxidised, partially unhindered 65 porphyrins can undergo C-C coupling yielding porphyrin oligomers, 13,14 this totally unsubstituted magnesium porphyrin should have unique redox reactivity.…”

Section: Introductionmentioning

confidence: 99%

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Exploring the redox reactivity of magnesium porphine. Insight into the origins of electropolymerisation

et al. 2010

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Magnesium(II) porphine, MgP (1), was synthesised according to the Lindsey procedure allowing to isolate and crystallise 1-formyldipyrromethane (2) as a synthetic intermediate. Unprecedented X-ray diffraction studies revealed multiple intermolecular associations in the crystal between neighbouring units of 2, namely hydrogen bonds and CH...pi. The electrochemical behaviour of 1 was examined by means of cyclic voltammetry. In oxidation, two well-defined and distinct steps are assigned to macrocycle concerned electron transfers yielding initially the pi-cation radical and pi-dication, respectively. The highly reactive dication condenses neutral magnesium porphine to form a diprotonated di-isoporphine species, which is assumed to be a key intermediate at the origin of the electropolymerisation. Electrolyses were performed at the potential of the pi-cation radical generation. Investigation of the electrolysed solution by UV-vis spectroscopy and MALDI-TOF spectrometry revealed the presence of several oligoporphyrins, with diporphine as an important product. In all the oligomers series, extensive demetallation is evidenced, due to the increasing acidity of the medium as oligomerisation progresses. This demetallation could be prevented by addition of 2,6-lutidine as a base prior to electrolysis. In the oligomer series, the porphine units seem to be connected through meso-meso bonds, an argument supported by certain features of the UV-vis spectrum. Finally, the mechanism of oxidative oligomerisation is discussed, from the point of view of the initial steps of the electropolymerisation.

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Section: Notes and Referencesmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Exploring the redox reactivity of magnesium porphine. Insight into the origins of electropolymerisation

et al. 2010

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“…This problem was overcome by using the more electron-rich magnesium porphyrin Mg6, which reacts cleanly at the meso positions to give Mg7. 18 Demetallation with TFA and reaction with zinc acetate were used to form the zinc complex Zn7. A range of reaction conditions were tested for the Heck± Sonogashira coupling of Zn7 with trimethylsilyl acetylene.…”

Section: Synthesismentioning

confidence: 99%

Synthesis and third order nonlinear optics of a new soluble conjugated porphyrin polymer

et al. 2001

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The synthesis of a new soluble conjugated porphyrin polymer 4 is reported. The MALDI TOF mass spectrum shows the presence of oligomers with up to 13 repeat units and GPC gives a M n of 53 kDa. The electronic absorption spectra of this polymer exhibit an intense Q band at 800 nm in solution and 853 nm in the solid state, demonstrating a high degree of conjugation. Electroabsorption spectroscopy shows that thin ®lms of 4 have lower resonant third order NLO susceptibility than our previous conjugated porphyrin polymer 2, whereas closed z-scan measurements indicate that the off-resonance real susceptibility, at 1064 nm, is exceptionally large for both polymers (x (3) R ~22610 216 m 2 V 22 ). Open z-scan measurements were also made at 1064 nm, demonstrating that the two polymers exhibit similar nonlinear absorption at this wavelength (b~1 cm GW 21 at 0.2 mM concentration).

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“…Porphyrins were used in a form of nickel complexes due to the enhanced reactivity of the metal complexes compared to the free bases porphyrins in electrophilic substitution reactions. [8,29] It is also known that nickel complexes are subjected to of VilsmeierHaack formylation with the highest reaction rate. [30] Synthesis To obtain N-substituted hydrazones of metal complexes of β-octaethylporphyrin and coproporphyrin I we used a method based on the interaction of meso-formyl derivatives of metal porphyrins with N-substituted hydrazines.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Study of New N-Substituted Hydrazones of Ni(II) Complexes of β-Octaethylporphyrin and Coproporphyrin I Tetraethyl Ester

Shkirdova¹,

Zamilatskov²,

Stanetskaya³

et al. 2017

MHC

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N-Substituted hydrazones of nickel complexes of β-octaethylporphyrin and tetraethyl ester of coproporphyrin I were obtained. These compounds can serve as intermediate compounds for the preparation of meso-functionalized derivatives of porphyrins by means of various reactions. In the first stage Vilsmeier-Haack reaction was carried out by the interaction of nickel complexes of β-octaethylporphyrin and tetraethyl ester of coproporphyrin I with N,N-dimethylformamide and phosphorus(V) oxochloride forming the so-called "phosphorus complex", which was hydrolyzed with saturated solution of sodium acetate. The corresponding meso-formyl derivatives of metal porphyrins were obtained as a result. Synthesis of the hydrazones was carried out by the reactions of meso-formyl derivatives with the hydrazines using trifluoroacetic acid as a catalyst. The result of the reaction was formation of hydrazones in the form of a mixture of E-and Z-isomers, which were separated using preparative thin layer chromatography. Thus a series of hydrazoneswith different substituents at the nitrogen atom was obtained. The structures of all obtained compounds were determined using the methods of NMR spectroscopy, electronic absorption spectroscopy and mass spectrometry. For nickel complex of tosylhydrazone derivative of β-octaethylporphyrin the crystal structure was determined using X-ray diffraction. X-ray analysis shows that porphyrin molecules in the crystal form dimers bonded by two hydrogen bonds between the hydrogen atom of the NH-group of hydrazone and the oxygen atom of the sulfonate groups.

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Reactivity of Unsubstituted Porphin

Cited by 26 publications

References 6 publications

Exploring the redox reactivity of magnesium porphine. Insight into the origins of electropolymerisation

Exploring the redox reactivity of magnesium porphine. Insight into the origins of electropolymerisation

Synthesis and third order nonlinear optics of a new soluble conjugated porphyrin polymer

Synthesis and Study of New N-Substituted Hydrazones of Ni(II) Complexes of β-Octaethylporphyrin and Coproporphyrin I Tetraethyl Ester

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