Porphyrin-quinone Cyclophanes Research Articles

Distance Dependence of Photoinduced Electron-Transfer: Syntheses and Properties of Biphenylene-Spacered Porphyrin-Quinone Cyclophanes

In continuation of previous syntheses of benzene-, naphthalene-, and anthracene-spacered porphyrin-quinone cyclophanes 1, 2, and 4, biphenylene-spacered porphyrin-quinone cyclophanes of structure 3 as the “missing link” between 2 and 4 were prepared in multistep syntheses. These donor-acceptor systems are of interest since, with regard to electron-transfer rates, they complete the series of 1, 2, and 4. As expected the electron-transfer of 3 proceeds between that of 2 and 4 in an especially steep region of distance dependences of electron-transfer rates.

Porphyrin–Quinone Cyclophanes with Gradually Varied Donor–Acceptor Distances

Porphyrin–Quinone Cyclophanes with Gradually Varied Donor–Acceptor Distances

Energy Gap and Temperature Dependence of Photoinduced Electron Transfer in Porphyrin-Quinone Cyclophanes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnergy Gap and Temperature Dependence of Photoinduced Electron Transfer in Porphyrin-Quinone CyclophanesH. Heitele, F. Poellinger, T. Haeberle, M. E. Michel-Beyerle, and H. A. StaabCite this: J. Phys. Chem. 1994, 98, 30, 7402–7410Publication Date (Print):July 1, 1994Publication History Published online1 May 2002Published inissue 1 July 1994https://doi.org/10.1021/j100081a028RIGHTS & PERMISSIONSArticle Views294Altmetric-Citations82LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1001 KB) Get e-Alerts

Syntheses and Properties of New Quinone‐Bridged Diphenyl‐ and Tetraphenylporphyrins

Syntheses and spectroscopic properties of the porphyrin-quinone cyclophanes 1, 2 and 3 of which structural and/or conformational studies have recently reported[1] are described. Physical properties related to photoinduced electron-transfer reactions like redox potentials, absorption and emission spectra were determined for these compounds.

Absence of dielectric relaxation effects on intramolecular electron transfer in porphyrin-quinone cyclophanes

We have measured photoinduced intramolecular electron transfer rates k et in two porphyrin-dichloroquinone cyclophanes varying the polarity, the temperature, and the dielectric relaxation time of the solvent. The reaction is most likely activationless or in the inverted region in all solvents. The adiabaticity parameter k = 4π V 2 eff/ khλ sτℓ for dynamic dielectric solvent control is estimated to cover the range 0.2 ⪕ k ⪕ 400. Nevertheless the rate k et was found to be almost independent of the solvent properties ( k et > 5 × 10 11 s −1) casting doubt on current ideas of dielectric relaxation effects on electron transfer.

Photoinduced electron transfer in porphyrin‐quinone cyclophanes, 6. Porphyrin‐quinone cyclophanes with gradually varied acceptor strength: Syntheses and characterizations

For studying intramolecular electron-transfer reactions, three groups of double- and single-bridged porphyrin-quinone cyclophanes 1–4, 5–9, and 11–14, resp., with gradual variation of quinone acceptor strengths were synthesized. As key intermediates for building up the porphyrin-cyclophane skeleton the correspondingly 3,6-substituted 1,4-bis[4-(2-formylphenyl)-butyl]-2,5-dimethoxybenzenes 15–20 were synthesized. Condensation with pyrrole yielded the doubly bridged porphyrin cyclophanes 42–45; via the bis(dipyrrolylmethyl) derivatives 46–51 and 64–67 the single-bridged porphyrin cyclophanes 58–63 and 72–75 were obtained by acidic condensation with triethyl formate. Cleavage of the methoxy groups and oxidation yielded the corresponding porphyrin-quinone systems. Some magnesium and zinc complexes of these cyclophanes are described. Spectroscopic data (MS, 1H NMR) are reported in support of the proposed structures.

Photoinduced electron transfer in porphyrin‐quinone cyclophanes, 5. Quinone‐porphyrin‐quinone and quinone‐porphyrin‐donor cyclophanes: Syntheses, structures and electron‐transfer‐related properties

In order to increase the driving force for photoinduced electron-transfer reactions of porphyrin-quinone cyclophanes, the zinc complexes 3a-e and 4a-e were prepared from the corresponding cyclophanes of the 1 and 2 series. Electron-transfer-related properties like redox potentials and fluorescence spectra were determined for 3a-e and 4a-e. The X-ray structure analysis of 4a indicates that for the very fast and solvent-independent electron transfer in these systems a specific mechanism involving an interaction of a quinone carbonyl group with the zinc might be considered as an alternative to through-space electron-transfer

Electron transfer in porphyrin—quinone cyclophanes studied on the pico- and femto-second time scale

Electron transfer in porphyrin—quinone cyclophanes is investigated by fluorescence and absorption spectroscopy with pico- and femto-second pulses. In nonpolar solvents, the S 1 state of the porphyrin shows a lifetime from 300 ps up to several nanoseconds, depending upon the number of quinones and upon their electron affinity. Comparative measurements in polar solvents demonstrate very fast electron transfer on a time scale between 1 and 10 ps. The results are analyzed with the aid of quantum-chemical calculations which give the energy of the charge transfer states and the relevant coupling strengths. For nonpolar solvents, theory suggests fluctuation-induced charge separation and/or direct radiationless internal conversion from the porphyrin S 1 to the ground state. In polar solution, the molecules exist in a tilted configuration with strong electronic coupling and charge transfer states well below the S 1 level, resulting in fast electron transfer and subsequent charge recombination within 10–40 ps.

Theoretical analysis of the photoinduced electron transfer in porphyrin—quinone cyclophanes

Quantum calculations of the INDO-S/CI type are performed on a porphyrin—quinone cyclophane complex to determine the molecular parameters which govern the photoinduced charge separation, such as energy locations of the excited state and the lowest charge transfer states as well as the electron transfer couplings. From the molecular dynamics studies, the structural arrangement of the quinone relative to the porphyrin and the reorganization energies of the solvents are extracted. The results are cast in analytic form, which shows explicitly the polarity dependence of the solvent-induced intramolecular electron transfer process. The theory is used to interpret experimental results in a companion paper.

ChemInform Abstract: Electron Transfer in Photoexcited Porphyrin Quinone Cyclophanes

ChemInformVolume 20, Issue 51 Physical Organic Chemistry ChemInform Abstract: Electron Transfer in Photoexcited Porphyrin Quinone Cyclophanes D. MAUZERALL, D. MAUZERALL Rockefeller Univ., New York, NY 10021, USASearch for more papers by this authorJ. WEISER, J. WEISER Rockefeller Univ., New York, NY 10021, USASearch for more papers by this authorH. STAAB, H. STAAB Rockefeller Univ., New York, NY 10021, USASearch for more papers by this author D. MAUZERALL, D. MAUZERALL Rockefeller Univ., New York, NY 10021, USASearch for more papers by this authorJ. WEISER, J. WEISER Rockefeller Univ., New York, NY 10021, USASearch for more papers by this authorH. STAAB, H. STAAB Rockefeller Univ., New York, NY 10021, USASearch for more papers by this author First published: December 19, 1989 https://doi.org/10.1002/chin.198951041Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume20, Issue51December 19, 1989 RelatedInformation

Electron transfer in photoexcited porphyrin quinone cyclophanes

The striking difference in fractions of fast versus slow components ofelectron transfer of the porphyrin mono- and bis-quinone cyclophanes are attributed to an orbital symmetry effect between the porphyrin and the quinone.