Alignment and Chirality of Porphyrin J Aggregates Formed at the Liquid–Liquid Interface of a Centrifugal Liquid Membrane Cell

Abstract

Previous direct observations of the J aggregates of diprotonated 5,10,15,20-tetraphenyl-21H,23H-porphine (H4TPP(2+)) formed at the dodecane-water interface in a centrifugal liquid membrane (CLM) cell using conventional CD spectroscopy have shown the existence of circular dichroic signals with a bisignated shape whose sign depends on the rotation direction of the cell. Herein we demonstrate that the determination of the optical Mueller matrix with a two-photoelastic modulator generalized ellipsometer (2-MGE), working in transmission mode, along with the assumption of a two superimposed twin Mueller matrices model (two opposite interfaces in the cylindrical rotation cell) allows us to infer the CD spectra due to overlapping linear polarizations from J aggregates at the front and back liquid-liquid interfaces in the rotating cell. The rotation direction dependence of the CD spectra was thoroughly interpreted by the present model considering the sign and the magnitude of the orientation angle between the front and back J aggregates. The present analysis should help us to understand the optical chirality due to the structural changes in supramolecular and macromolecular systems under flow shear forces as well as changes in birefringence.

Generation of circular dichroism from superposed porphyrin films

“…Ribó et al discovered the generation of optical chirality from an achiral porphyrin solution, which was treated by a rotary evaporater 3,4 . Our group also observed similar phenomena in the measurements of the protonation of achiral porphyrin at the liquid–liquid interface in a centrifugal liquid‐membrane cell 5,6 . Scolaro et al observed the optical chirality of aggregates induced by rotational and magnetic forces 7 .…”

Aggregation behavior of tetraphenylporphyrin in aqueous surfactant solutions: Chiral premicellar J-aggregate formation

“…Another [24,25] is the absence of both inorganic salts and nonpolar organic solvents in the reaction system, which allows the structural study of the porphyrin selfassembly products without any additional treatment or purification procedures. The maximum TPP aggregateto-monomer ratio of 1.8 is obtained for 5 × 10 -4 M SDS solution, which is only 10% of the SDS cmc value in pure water.…”

Structure and principles of self-assembly of giant “sea urchin” type sulfonatophenyl porphine aggregates

“…Numerous applications have been developed for TPPS 4 and other porphyrin aggregates including humidity ISSN 1998-0124 CN 11-5974/O4 https://doi.org/10.1007/s12274-021-4048-x biosensors [19], artificial light energy harvesting and transfer systems [20,21], and photodynamic therapy agents [22,23]. While most studies are conducted on homogeneous aggregates of hundreds of nanometers in size, differently ordered aggregates can further interact and assemble into complex hierarchical structures characteristic of living organisms [6,[24][25][26][27][28][29]. The self-organization of TPPS 4 molecules into higher complexity hierarchical microstructures is not well understood and is the focus of this study.…”