5-Phenyl-10,15,20-Tris(4-sulfonatophenyl)porphyrin: Synthesis, Catalysis, and Structural Studies

Abstract

A convenient protocol for the preparation of 5-phenyl-10,15,20-tris(4-sulfonatophenyl)porphyrin, a water-soluble porphyrin with unique aggregation properties, is described. The procedure relies on the one-pot reductive deamination of 5-(4-aminophenyl)-10,15,20-tris(4-sulfonatophenyl)porphyrin, that can be in turn easily obtained from 5,10,15,20-tetraphenylporphyrin by a known three-step sequence involving mononitration, nitro to amine reduction and sulfonation of the phenyl groups. This method provides the title porphyrin in gram scale, and compares very favorably with the up to now only described procedure based on the partial sulfonation of TPP, that involves a long and tedious chromatographic enrichment of the final compound. This has allowed us to study for the first time both the use of its zwitterionic aggregate as a supramolecular catalyst of the aqueous Diels–Alder reaction, and the morphology of the aggregates obtained under optimized experimental conditions by atomic force microscopy and also by transmission electron cryomicroscopy.

Chiral Amphiphilic Secondary Amine-Porphyrin Hybrids for Aqueous Organocatalysis

“…In aqueous solutions at acidic pH, typically at values below 4.8, the diprotonation of the central pyrroleninic core induces the formation of the so-called J-aggregates [ 11 ], stabilized by ion-pair contacts between the cationic porphyrin centers and the anionic sulfonate groups of the periphery. In the context of our research program on the use of amphiphilic porphyrins and their J-aggregates in aqueous organocatalysis [ 12 , 13 ], we recently found that by covalently binding a cyclic secondary amine with a 4-sulfonatophenylporphyrin scaffold we could modulate the organocatalytic properties of the hybrid structures 1 and 2 in aqueous aminocatalytic reactions that can take place through enamine intermediates ( Scheme 1 ). In particular, we showed that the catalytic activity of the cyclic secondary amine moieties of the functionalized porphyrins 1 and 2 is indirectly regulated by varying the pH value of the medium, which controls the aggregation/deaggregation state of the porphyrin scaffold.…”

Ionic supramolecular polymerization of water-soluble porphyrins: balancing ionic attraction and steric repulsion to govern stacking

“…, H 2 TPPS 2 and H 2 TPPS 3 ). 26 Studies of these modified porphyrins have revealed that they are still capable of self-assembly through ionic interactions, even with a low number of sulfonate groups, thereby leading to the creation of tape- and sheet-like 27 and as tubular 25,28,29 structures. Although these porphyrin derivatives have potential to produce a variety of porphyrin-based supramolecular structures, there have been no previous attempts to synthesize H 2 TPPS 4 derivatives in which two sulfonic acid moieties at opposite meso ( trans ) positions have been replaced by nonionic groups.…”

Automated and Continuous-Flow Platform to Analyze Semiconductor–Metal Complex Hybrid Systems for Photocatalytic CO2 Reduction

“…The free base ligand, tppS3N1 (41.7 mg), was prepared as described in the literature , and added to a 125 mL, three-neck flask containing 10 mL of methanol, and the resulting solution was stirred at 60 °C under nitrogen for 10 min. A solution of cobalt­(II) acetate tetrahydrate (57.1 mg) in 5 mL of methanol and 15 mL of chloroform was then added, and the progress of the stirred reaction was monitored by thin-layer chromatography and UV–vis spectroscopy.…”