Porphycene—a Novel Porphin Isomer

Vogel, Emanuel; Köcher, Matthias; Schmickler, Hans; Lex, Johann

doi:10.1002/anie.198602571

Cited by 528 publications

(422 citation statements)

References 19 publications

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“…Porphycene 1 ([18]porphyrin-(2.0.2.0), see Figure 54) is the structural isomer of porphyrin 2 ([18]porphyrin-(1.1.1.1)) first synthesized [317] in a series including corrphycene ( [18]porphyrin-(2.1.0.1)) [318] and hemiporphycene ( [18]porphyrin-(2.1.1.0)) [319]. Porphycenes have attracted much attention since their synthesis [320].…”

Section: Porphycenesmentioning

confidence: 99%

Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

Gellini

Salvi

2010

Symmetry

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The paper introduces general considerations on structural properties of aromatic, antiaromatic and non-aromatic conjugated systems in terms of potential energy along bond length alternation and distortion coordinates, taking as examples benzene, cyclobutadiene and cyclooctatetraene. Pentalene, formally derived from cyclooctatetraene by cross linking, is also considered as a typical antiaromatic system. The main interest is concerned with [n]annulenes and model [n]annulene molecular systems, n ranging from 10 to 18. The rich variety of conformational and configurational isomers and of dynamical processes among them is described. Specific attention is devoted to bridged [10]-and [14]annulenes in the ground and lowest excited states as well as to s-indacene and biphenylene. Experimental data obtained from vibrational and electronic spectroscopies are discussed and compared with ab initio calculation results. Finally, porphyrin, tetraoxaporphyrin dication and diprotonated porphyrin are presented as annulene structures adopting planar/non-planar geometries depending on the steric hindrance in the inner macrocycle ring. Radiative and non-radiative relaxation processes from excited state levels have been observed by means of time-resolved fluorescence and femtosecond transient absorption spectroscopy. A short account is also given of porphycene, the structural isomer of porphyrin, and of porphycene properties.

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Section: Porphycenesmentioning

confidence: 99%

Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

Gellini

Salvi

2010

Symmetry

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“…Characterization, identification and the measurement of the distinctive physico-chemical properties of isomeric molecules are therefore a subject of fundamental importance in chemistry. For porphyrins, a multitude of isomers with peculiar properties have been generated by changing the number of carbon atoms between pyrrole rings such as in porphycenes, 1 porphycerins, 2,3 hemiporphycenes, 4 and isoporphycenes 5 (Scheme 1). Exceptional examples of porphyrin isomers are Scheme derived from "confusion" and "neo-confusion", where the new structures are generated by changing the position of the nitrogen atom.…”

Section: Introductionmentioning

confidence: 99%

Corrole isomers: intrinsic gas-phase shapes via traveling wave ion mobility mass spectrometry and dissociation chemistries via tandem mass spectrometry

et al. 2012

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PAPERCorrole and four of its isomers with subtle structural changes promoted by exchange of nitrogen and carbon atoms in the corrole ring have been studied by traveling wave ion mobility mass spectrometry and collision induced dissociation experiments. Significant differences in shapes and charge distributions for their protonated molecules were found to lead to contrasting gas phase mobilities, most particularly for corrorin, the most "confused" isomer. Accordingly, corrorin was predicted by B3LYP/6-31g(d,p) and collisional cross section calculations to display the most compact tri-dimensional structure, whereas NCC4 and corrole were found to be the most planar isomers. Better resolution between the corrole isomers was achieved using the more polarizable and massive CO 2 as the drift gas. Sequential losses of HF molecules were found to dominate the dissociation chemistry of the protonated molecules of these corrole isomers, but their unique structures caused contrasting labilities towards CID, whereas NCC4 showed a peculiar and structurally diagnostic loss of NH 3 , allowing its prompt differentiation from the other isomers.

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“…Finally, it has yet to be determined whether the movement of the two protons in the excited state occurs in an asynchronous or a stepwise fashion. Recent syntheses of structural isomers of porphyrin -porphycene (2) [44], corrphycene (3) [45] and hemiporphycene (4) [46] (Fig. 1) may turn out to be of great help in the study of tautomerization mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Light-Induced Tautomerization in Porphyrin Isomers

Waluk

1999

Acta Phys. Pol. A

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Double proton tautomerization occurring in porphyrin and its structural isomers represents a special case of a chemical transformation in which the substrate and the product are formally the same. The methods used for the investigation of this kind of processes are based on polarized spectroscopy and high-resolution techniques, such as matrix isolation. Their combined use results in obtaining information pertinent to the mechanism of proton transfer, regarding e.g., the values of proton transfer rates, structure of the tautomeric forms or the shape of the potential energy surfaces. In addi-• tion, these procedures provide a way of obtaining spectral, photophysical and structural data that would be otherwise difficult to gain. The examples include determination of transition moment directions, assignment of electronic and vibrational states, elucidation of the character of the substitutional replacement of the rare gas matrix atoms by the chromophore, and the analysis of the nature of the symmetry lowering due to the matrix cage.

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Porphycene—a Novel Porphin Isomer

Abstract: Angen Chem. Inr Ed. Engl. 25 (1986) No. 3 0 VCH Verlagsgesellschafi mbH. 0-6940 Wernheim, I986 0570-0833/86/0303-0259 $ 02 50/0

Cited by 528 publications

References 19 publications

Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

Structures of Annulenes and Model Annulene Systems in the Ground and Lowest Excited States

Corrole isomers: intrinsic gas-phase shapes via traveling wave ion mobility mass spectrometry and dissociation chemistries via tandem mass spectrometry

Light-Induced Tautomerization in Porphyrin Isomers

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