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

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• 作者：Hideaki Takechi ; Adolf Canillas ; Josep M. Rib贸 ; Hitoshi Watarai
• 刊名：Langmuir
• 出版年：2013
• 出版时间：June 18, 2013
• 年：2013
• 卷：29
• 期：24
• 页码：7249-7256
• 全文大小：550K
• 年卷期：v.29,no.24(June 18, 2013)
• ISSN：1520-5827

文摘

Previous direct observations of the J aggregates of diprotonated 5,10,15,20-tetraphenyl-21H,23H-porphine (H₄TPP²⁺) formed at the dodecane鈥搘ater 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鈥搇iquid 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.