The monomer-aggregate equilibrium of four phenothiazine (PN) dyes, containing thionine (TH), methylene blue (MB), new methylene blue (NMB), and 1,9-dimethylmethylene blue (DMB), in the tungsten(VI) oxide (WO(3)) nanocolloid solution has been investigated by means of UV-vis spectroscopy. Addition of PN dye into the WO(3) nanocolloid solution brought about significant changes in the absorption spectrum, suggesting the formation of H-type (face-to-face fashion) trimer on the WO(3) nanocolloid surface. The adsorptivity of PN dyes onto the WO(3) nanocolloid surface was diminished by the raising the ionic strength, indicating the evidence of the electrostatic interaction between cationic PN dye and negatively charged WO(3) nanocolloids. The detail analysis of each spectral data provided insight into the effect of molecular structure of PN dyes on the adsorption and aggregation behaviors on the WO(3) nanocolloid surface. Moreover, in situ measurement of PN dye aggregation using the centrifugal liquid membrane (CLM) technique revealed that the aggregation of PN dyes on the WO(3) nanocolloid surface proceeded in a two-step three-stage (monomer --> dimer --> trimer) formation. The aggregation mechanism of PN dyes on the WO(3) nanocolloid surface was discussed on the basis of Kasha's exciton theory.

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.

The centrifugal liquid membrane (CLM) cell has been utilized for chiroptical studies of liquid-liquid interfaces with a conventional circular dichroism (CD) spectropolarimeter. These studies required the characterization of optical properties of the rotating cylindrical CLM glass cell, which was used under the high speed rotation. In the present study, we have measured the circular and linear dichroism (CD and LD) spectra and the circular and linear birefringence (CB and LB) spectra of the CLM cell itself as well as those of porphyrine aggregates formed at the liquid-liquid interface in the CLM cell, applying Mueller matrix measurement method. From the results, it was confirmed that the CLM-CD spectra of the interfacial porphyrin aggregates observed by a conventional CD spectropolarimeter should be correct irrespective of LD and LB signals in the CLM cell.

A microscope device to measure the circular dichroism (CD) spectra of a specified microscopic region of chiral samples was constructed by combining of a couple of objective lenses and a CCD camera, which was installed in a sample chamber of a commercially available CD spectropolarimeter. By using this apparatus, high quality micro-CD spectra in the 60 × 60 μm region of samples could be measured. Micro-CD spectra of thin film of chiral DNA samples on glass and a natural kidney bean leaf were measured, and the potential of the micro-CD apparatus was successfully demonstrated.

In the methylene blue (MB)/phenylalanine (Phe)/tungsten(VI) oxide (WO 3 ) colloid ternary aqueous solution, the MB Haggregates, which could recognize the chirality of D-and L-10 Phe, were formed and investigated by means of UV-Vis absorption and CD spectroscopy. These results demonstrate a chirality transfer and amplification from only the preadsorbed Phe molecules to MB aggregates formed on the WO 3 colloid surface via non-covalent interactions. 15Amino acids are important bioactive substances, they are widely used in the food, chemical and pharmaceutical industries. [1,2] Enantioselective recognition of amino acids is an important methodology for providing a better understanding of the origin of homochirality and leading to better development of biochemical 20 and pharmaceutical chiral devices. [3][4][5][6] Great efforts have been made to recognize amino acid enantiomers, but designing an efficient method to recognize amino acids is still a challenging task. [7] There are great interests concerning the transformation of chiral information from a chiral template to achiral molecules and 25 supramolecular systems.[8] By forming intrinsically chiral assemblies, or by aggregating on a chiral template, the symmetric achiral molecules could also present supramolecular chirality. Construction of a chiral molecular assembly is very important in supramolecular chiral recognition. [9][10][11] The driving force for the 30 formation of chiral supermolecules is generally constructed on the non-covalent interactions, such as van der Waals interactions, hydrogen bonds, π-π stacking, electrostatic interaction and hydrophobic interactions. [12][13][14] Phenothiazine derivatives such as methylene blue (MB) play 35 important roles in spectroscopic studies for their novel and tunable spectroscopic, photophysical and photochemical properties. [15,16] Their unique planar as well as rigid molecular geometry and aromatic electronic feature delocalized over the molecular frame enable them to be well investigated in the field 40 of constructing supramolecular assemblies by non-covalent interactions. In our previously reported work, [17] we found that the cationic MB dyes could form ideal H-type (face-to-face fashion) trimer on the negative charged tungsten(IV) oxide (WO 3 ) nanocolloid surface via the supramolecular self-assembly 45 process in the aqueous solution.Inspired by this finding, we have introduced the concept of "chirality" into the MB/WO 3 binary system by adding phenylalanine (Phe) which is one of the amino acids that are joined together to form proteins. Once the supramolecular 50 chirality in the MB/Phe/WO 3 ternary system has been achieved, one can expect that the system would show more important and more interesting optical active architectures from the viewpoints of chiral recognition mechanism and organic/inorganic hybrid material. Herein, we describe an investigation of supramolecular