Chiral sign selection on the J‐aggregates of diprotonated tetrakis‐(4‐sulfonatophenyl)porphyrin by traces of unidentified chiral contaminants present in the ultra‐pure water used as solvent

Abstract

Traces of biological contaminants that cannot be detected, but are expected to be present, in ultra-pure water suffice to select the emerging chiral sign in the spontaneous mirror symmetry breaking that takes place during the formation of the J-aggregates of the amphiphilic diprotonated tetrakis-(4-sulfonatophenyl)porphyrin (H(4)TPPS(4)(2-)). This is demonstrated by competition experiments with a chiral cationic surfactant. The sensitivity of the detection depends on the hierarchical control of the H(4)TPPS(4)(2-) self-aggregation.

Mixtures of achiral amphiphilic cyanine dyes form helical tubular J-aggregates

“…Due to the exceptionally strong interaction between the monomers transition dipole moments [16,17] cyanine dyes can form so-called J-aggregates in aqueous solution, which are characterized by a high degree of positional molecular order, a dramatic red-shift and a narrowing of their lowest energetic electronic transition (relative to the dye monomer) [18,19]. Under certain conditions even optically active J-aggregates can be obtained [20][21][22][23][24][25]. The established approach uses the structural information encoded within a chiral template on which the dye molecules spontaneously aggregate.…”

“…Meanwhile it became also clear, that certain achiral cyanine dyes [23,24] could spontaneously assemble into optically active cylindrical aggregates without any added chiral auxiliaries. The reason for that phenomenon remained unexplained, but just recently it was suggested that biological contaminants present in the ultra-pure water commonly used for preparation could be a source of those effects [25].…”

Effect of zinc cations on the kinetics of supramolecular assembly and the chirality of porphyrin J-aggregates

“…13,14 One proposal is that this symmetry breaking is due to the adventitious presence of traces of chiral impurities, 15,16 i.e. , it is once again due to an external driving force.…”

The Direct Synthesis of 2-N-Methyl-5,10,15,20-tetrakis-(4′-sulfophenyl)-2-aza-21-carbaporphyrin J-Aggregates

“…[9][10][11][12][13][14][15][16][17][18][19] The Direct Synthesis of N-Methyl-tetrakis(4′-sulfophenyl)azacarbaporphyrin J-Aggregates is a self-assembly monomer, and J-aggregates formation is a result of intermolecular substitution of water molecules for sulfonate groups. The unique characteristic of these structures is a strong red shift of absorption bands in UV-Vis spectra of J-aggregates as compared with monomers, caused by resonance absorption.…”