Porphyrins with multiple crown ether voids: novel systems for cation complexation studies

Thanabal, V.; Krishnan, V.

doi:10.1021/ja00377a016

Cited by 137 publications

(62 citation statements)

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“…Hans Fischer, in one of the earliest syntheses, originally used the aldehyde for preparing porphine. [14] Use of two equivalents of aldehyde 11 together with one equivalent of the relatively stable dipyrromethane (13) [15] in a condensation reaction would then constitute an equivalent of the bilane. We anticipated that the deactivating effect of the formyl group in 11 would favor a reaction with 12 over self-condensation, as outlined in Scheme 1.…”

Section: Resultsmentioning

confidence: 99%

“…Herein we show that porphyrins of the A-(2) and A 2 -type (7) can be prepared by either classical condensation reactions involving dipyrromethanes (13) or tripyrranes (28) or alternatively by S N Ar reactions of unsubstituted porphine 1. [10] This opens the way for the first time for a synthesis of ABCD-type porphyrins by successive introduction of meso substituents.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Mono‐ and Disubstituted Porphyrins: A‐ and 5,10‐A₂‐Type Systems

Ryppa

Senge

Hatscher

et al. 2005

Chemistry A European J

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General syntheses have been developed for meso-substituted porphyrins with one or two substituents in the 5,10-positions and no beta substituents. 5-Substituted porphyrins with only one meso substituent are easily prepared by an acid-catalyzed condensation of dipyrromethane, pyrrole-2-carbaldehyde, and an appropriate aldehyde using a "[2+1+1]" approach. Similarly, 5,10-disubstituted porphyrins are accessible by simple condensation of unsubstituted tripyrrane with pyrrole and various aldehydes using a "[3+1]" approach. The yields for these reactions are low to moderate and additional formation of either di- or monosubstituted porphyrins due to scrambling of the intermediates is observed. However, the reactions can be performed quite easily and the desired target compounds are easily removed due to large differences in solubility. A complementary and more selective synthesis involves the use of organolithium reagents for S(N)Ar reactions. Reaction of in situ generated porphyrin (porphine) with 1.1-8 equivalents of RLi gave the monosubstituted porphyrins, while reaction with 3-6 equivalents of RLi gave the 5,10-disubstituted porphyrins in yields ranging from 43 to 90 %. These hitherto almost inaccessible compounds complete the series of different homologues of A-, 5,15-A(2)-, 5,10-A(2)-, A(3)-, and A(4)-type porphyrins and allow an investigation of the gradual influence of type, number, and regiochemical arrangement of substituents on the properties of meso-substituted porphyrins. They also present important starting materials for the synthesis of ABCD porphyrins and are potential synthons for supramolecular materials requiring specific substituent orientations.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of Mono‐ and Disubstituted Porphyrins: A‐ and 5,10‐A₂‐Type Systems

Ryppa

Senge

Hatscher

et al. 2005

Chemistry A European J

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“…98-8.87 (m, 8 H, b-pyrrolic H), 8.24-8.17 (m, 6 H, o-phenyl H), 7.79-7.66 (m, 11 H, m,p-phenyl H(9 H) H 2 -5, 10,15,crown-6)-porphyrin (3 a): This compound was prepared according to the reported procedures [27] for H 2 -5, 10,15,20-tetra(benzo-[15]crown-5)-porphyrin with some modifications. A mixture of 4'-formylbenzo- [18]crown-6 (1 b) (502.3 mg, 1.5 mmol) and pyrrole (95 mL, 91.9 mg, 1.4 mmol) was refluxed in propionic acid (115 mL) for 3 h. The crude product was purified on a basic alumina column with chloroform (116 mg,~5 %).…”

Section: Methodsmentioning

confidence: 99%

Effect of Axial Ligation or π–π‐Type Interactions on Photochemical Charge Stabilization in “Two‐Point” Bound Supramolecular Porphyrin–Fullerene Conjugates

D’Souza

Chitta

Gadde

et al. 2005

Chemistry A European J

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Two types of structurally well-defined, self-assembled zinc porphyrin-fullerene conjugates were formed by "two-point" binding strategies to probe the effect of axial ligation or pi-pi-type interactions on the photochemical charge stabilization in the supramolecular dyads. To achieve this, meso-tetraphenylporphyrin was functionalized to possess one or four [18]crown-6 moieties at different locations on the porphyrin macrocycle while fullerene was functionalized to possess an alkyl ammonium cation, and a pyridine or phenyl entities. As a result of the crown ether-ammonium cation complexation, and zinc-pyridine coordination or pi-pi-type interactions, stable zinc porphyrin-fullerene conjugates with defined distance and orientation were formed. Evidence for the zinc-pyridine complexation or pi-pi-type interactions was obtained from the spectral and computational studies. Steady-state and time-resolved emission studies revealed efficient quenching of the zinc-porphyrin singlet excited state in these dyads, and the measured rates of charge separation, k(CS) were found to be slightly better in the case of the dyads held by axial coordination and crown ether-cation complexation. Nanosecond transient absorption studies provided evidence for the electron transfer reactions, and these studies also revealed charge stabilization in these dyads. The lifetimes of the radical ion pairs were found to depend upon the type of porphyrins utilized to form the dyads, that is, porphyrin possessing the crown ether moiety at the ortho position of one of the phenyl rings yielded prolonged charge stabilized states. Addition of pyridine to the supramolecular dyads eliminated the zinc-pyridine coordination or pi-pi-type interactions of the "two-point" bound systems due to the formation of a new zinc-pyridine axial bond thus giving a unique opportunity to probe the effect of axial coordination or pi-pi interactions on k(CS) and k(CR). Under these conditions, the measured electron transfer rates revealed faster k(CS) and slower k(CR) as compared to those obtained in the absence of added pyridine. The evaluated lifetimes of the radical ion-pairs were found to be hundreds of nanoseconds and were longer in the presence of pyridine.

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“…[4] Одним из известных свойств краун-эфиров, которое используется в супрамолекулярном дизайне, является способность образовывать сэндвичевые комплексы с от-носительно большими катионами металлов. [5][6][7] Редким классом ОМС являются таутомерные хро-моионофоры. [8][9][10][11][12] Катион-индуцированные изменения в спектрах поглощения этих соединений обусловлены сдвигом таутомерного равновесия.…”

Section: T P Martyanov Et Alunclassified

Effect of Interchromophoric Stacking Interactions on the Stability of the Sandwich-Type Complexes of 1-Hydroxy-9,10-anthraquinone-9-iminobenzo-15-crown-5 ether with Metal Cations

Martyanov¹,

Ushakov²,

Klimenko³

2013

MHC

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Porphyrins with multiple crown ether voids: novel systems for cation complexation studies

Cited by 137 publications

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Synthesis of Mono‐ and Disubstituted Porphyrins: A‐ and 5,10‐A₂‐Type Systems

Synthesis of Mono‐ and Disubstituted Porphyrins: A‐ and 5,10‐A₂‐Type Systems

Effect of Axial Ligation or π–π‐Type Interactions on Photochemical Charge Stabilization in “Two‐Point” Bound Supramolecular Porphyrin–Fullerene Conjugates

Effect of Interchromophoric Stacking Interactions on the Stability of the Sandwich-Type Complexes of 1-Hydroxy-9,10-anthraquinone-9-iminobenzo-15-crown-5 ether with Metal Cations

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Porphyrins with multiple crown ether voids: novel systems for cation complexation studies

Cited by 137 publications

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Synthesis of Mono‐ and Disubstituted Porphyrins: A‐ and 5,10‐A2‐Type Systems

Synthesis of Mono‐ and Disubstituted Porphyrins: A‐ and 5,10‐A2‐Type Systems

Effect of Axial Ligation or π–π‐Type Interactions on Photochemical Charge Stabilization in “Two‐Point” Bound Supramolecular Porphyrin–Fullerene Conjugates

Effect of Interchromophoric Stacking Interactions on the Stability of the Sandwich-Type Complexes of 1-Hydroxy-9,10-anthraquinone-9-iminobenzo-15-crown-5 ether with Metal Cations

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Synthesis of Mono‐ and Disubstituted Porphyrins: A‐ and 5,10‐A₂‐Type Systems

Synthesis of Mono‐ and Disubstituted Porphyrins: A‐ and 5,10‐A₂‐Type Systems