Construction of Giant Porphyrin Macrorings Self‐Assembled from Thiophenylene‐Linked Bisporphyrins for Light‐Harvesting Antennae

Abstract

As a model of bacterial photosynthetic light-harvesting antenna, a large number of porphyrin units were organized into barrel-shaped macrorings. Two imidazolylporphyrinatozinc(II) molecules were linked through either unsubstituted thiophenes or 3,4-dioctylthiophenes 1 a and 1 b, respectively. These structures were spontaneously organized by complementary coordination of the imidazolyl to zinc and produced a series of self-assembled fluorescent polygonal macrorings under high dilution conditions. The ring size increased compared with previous m-phenylene examples. The size distribution was also controlled by the presence of octyl substituents. A wide distribution of macrorings from 7- to >15-mer was obtained from 1 a, whereas macrorings ranging from 7- to 11-mer with a maximum population focused at the 8-mer were formed with 1 b. The size distribution was governed by competition between entropy-favored, smaller-ring formation and the enthalpy-favored, less-strained larger macroring. The UV/Vis spectra showed a gradual redshift for the larger rings reflecting an increase in the transition dipole interactions.

Supramolecular Organization of Porphyrins and Phthalocyanines by Use of Biomimetic Coordination Methodology

“…95 between the favorable entropy and enthalpic instability due to the angular strain as the key factor of the size distribution of the organized macrocyclic wheel ( Figure 15). …”

“…95 The size of the organized porphyrin arrays is susceptible to structural variation of the bridging group, and is therefore controllable by the molecular design of the internal angular modulation. When thiophene is employed as the bridging group of the gable-type porphyrins 35 and 36, the angle between the two porphyrins is estimated to be 148°.…”

A Novel Colorimetric and Fluorescent pH Sensor Derived from Iminocoumarin and Thiophene‐Carboxaldehyde

“…By referring to the literature method , the formyl group in thiophene‐2‐carboxaldehyde was protected by a reaction with neopentyl glycol in the presence of sulfamic acid as a catalyst to produce compound 1 in 66% yield. Formylation of compound 1 by butyl lithium, tetramethylethylene diamine, and N , N ‐dimethylformamide (DMF) afforded compound 2 in 60% yield , which reacted with coumarin‐2‐imine 4 (obtained from 2‐cyanomethylbenzimidazole and 4‐diethylaminosalicylal in 56% yield) afforded a target molecule 5 in 78% yield. The chemical structures of the synthesized compounds were characterized by 1 H NMR, 13 C NMR, IR, and mass spectrum.…”

“…5‐(5,5‐Dimethyl‐1,3‐dioxan‐2‐yl)thiophene‐2‐carboxaldehyde (compound 2 ) was obtained as an oil by using the method reported in the literature . 2‐Cyanomethylbenzimidazole ( 3 ) was prepared from o ‐phenylenediamine and ethyl cyanoacetate according to the literature procedures, mp 210–211°C (lit.…”

A Candidate for Multitopic Probes for Ligand Discovery in Dynamic Combinatorial Chemistry

“…We have developed ImZnP into bis-ImZnP systems, in which two ImZnPs are connected directly or through appropriate spacers. They spontaneously produce oligomeric/polymeric and cyclic [22,23]/linear array systems [24,25,26]. For example, a Gable zinc porphyrin (GP), in which two ImZnPs are connected through an m -phenylene moiety, gave a mixture of pentameric and hexameric GPs quantitatively in solution (Figure 3 and Figure 4).…”