title: 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.
authors.affiliation: Institute for NanoScience Design, Osaka University, Toyonaka, Osaka, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takechi
authors.forename: Adolf
authors.initials: A
authors.lastname: Canillas
authors.forename: Josep M
authors.initials: JM
authors.lastname: Ribó
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Watarai
mesh_terms: D002498:Centrifugation; D002942:Circular Dichroism; D011166:Porphyrins / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D011166:Porphyrins