Supramolecular Complexation of Porphyrin and Quinone with Two Coordination Bonds and Intramolecular Electron Transfer

Abstract

<jats:p> V-shaped zinc porphyrin dimer and quinone with two pyridyl groups have been rationally designed and synthesized to assemble a porphyrin-quinone supramolecule with two coordination bonds. Selective formation of the 1:1 bridging structure between the host-guest molecules was seen by <jats:sup>1</jats:sup> H NMR and UV-Vis absorption spectroscopy. Molecular mechanics calculation suggests that the bridging structure has rigidity as well as flexibility in geometry between the redox pair, which supports the interpretation of <jats:sup>1</jats:sup> H NMR studies. Intramolecular photoinduced electron transfer from the excited singlet state of the porphyrin to the quinone was observed by steady-state fluorescence spectra and picosecond fluorescence lifetime measurements. </jats:p>

Self-organization principles in the formation of multiporphyrin complexes and "semiconductor quantum dot-porphyrin" nanoassemblies

“…Notably, K C values for triads containing dimers with a phenyl spacer are by two or three orders of magnitude larger than those for the binding of Znporphyrins [61,66] and their dimers [41] with pyridine and related ligands. On the other hand, these values are close to complexation constants measured for complexes of Znporphyrin dimer with two pyridinelinked quinone dipyridylsubstituted porphyrins (K C = 1.1 × 10 7 M 1 [80]) and for twofold coordinated complexes of Zn 2 gable porphyrins with N,N ′diimidazolylmethane or g,g′dipyridylmethane, respectively [81]). Additionally, (ZnHTPP) 2 and (ZnOEP) 2 Ph are complexed almost completely at molar ratio x = C L /C D0 = 1.…”

“…The larger complexation constants for the coordination of the bidentate porphyrin extraligand to these dimers suggest that each complex consists of one dimer and one free base forming a triad of the macrocycles. Like the complexes described in references [80,81], the triads based on dipyridylsubstituted porphyrin free bases and (ZnHTPP) 2 , (ZnTPP) 2 or (ZnOEP) 2 Ph are characterized by strong allosteric behavior showing that the first binding accelerates the second binding because of the chelate effect. In addition, values of activation energy measured for these triads (E a = 0.7-0.8 eV, evaluation method is shown in Fig.…”

Interaction of multiporphyrin systems with molecular oxygen in liquid solutions: extra-ligation and screening effects

“…At present, supramolecular chemistry is reaching highly elaborate levels of sophistication and the analysis of the co-operative behaviour of subunits within controlled spatial assemblies involving molecular recognition, catalysis, molecular devices, etc. In this respect, a non-covalent self-assembly based on the ligand coordination properties of metalloporphyrins (Zn, Mg, Co, Fe, Ni) seems to be an alternative way for the construction and investigation of a variety of artificial supramolecular systems with different geometry, spectral and photophysical characteristics [1][2][3][4][5][6][7][8][9]. Being studied in solutions at 77-293 K, these coordinatively formed multiporphyrin arrays have shown efficient light-harvesting properties and light-driven intracomplex electron transfer.…”

Molecularly imprinted receptor having metalloporphyrin-based signaling binding site

“…A functional monomer 1 was prepared by the reaction of methacryloyl chloride with 5,10,15-tris(4-isopropylphenyl)-20-(4-hydroxyphenyl)porphyrin zinc(ii) complex that was prepared according to the procedure reported elsewhere. 14 The structure of 1 was confirmed by 1 H NMR. As a model template, 9-EA was used for examining the metalloporphyrin-based molecular imprinting system since a 1 : 1 complexation of a porphyrin zinc complex and 9-EA has already been known.…”