An interfacial sol-gel synthesis of inorganic hollow microspheres in room-temperature ionic liquids is newly developed. When metal alkoxides such as titanium tetrabutoxide, Ti(OBu)4, are dissolved in anhydrous toluene and injected into 1-buthyl-3-methylimidazolium hexafluorophosphate ([C4mim]PF6) under vigorous stirring, hollow titania microspheres are formed. The present technique is widely applicable to the reactive metal alkoxides such as Zr(OBu)4, Hf(OBu)4, Nb(OBu)4, and InSn3(OR)x, giving a general route to the metal oxide microspheres. When gold nanoparicles and carboxylate-containing dyes such as fluorescein isothiocyanate (FITC) are dissolved in the toluene microdroplets, they are stably immobilized in the microsphere shells. Calcination of the titania gel microspheres gives anatase TiO2 microspheres. The present method provides the first example of inorganic hollow microspheres formed in ionic liquids, and the ability to modify microspheres with metal nanoparticles or functional organic molecules would be widely applied to the design of smart organic/inorganic hybrid materials.

Circularly polarized luminescence, or CPL, is a luminescence phenomenon that provides the differential emission intensity of right and left circularly polarized light, thereby providing information on the excited state properties of the chiral molecular systems. In recent years, there has been a growing interest toward the development of organic chromophores capable of circularly polarized emission due to their potential applications in sensors, asymmetric synthesis as well as display and optical storage devices. The major drawback with organic molecules is the low dissymmetric factors exhibited by these systems. One of the recent strategies adopted for the improvement in luminescence dissymmetry of organic systems is through the controlled self-assembly of chromophores. In this Perspective, we highlight the recent experimental and theoretical developments in the field of chiral organic chromophoric systems and their self-assembly, that has produced promising results toward the enhancement of glum values in CPL.

Ether-containing ionic liquids are developed, which are capable of dissolving carbohydrates such as β-d-glucose, α-cyclodextrin, amylose, agarose, and a glycosylated protein, glucose oxidase. When glycolipids are dispersed in these sugar-philic ionic liquids, stable bilayer membranes are formed. They display reversible thermal transformation from fibrous assemblies to vesicles. Physical gelation of ionic liquids occurs by dissolving amide-group-enriched glycolipids, providing a first example of self-assembling ionogels. The ability to dissolve carbohydrates in ionic liquids and the formation of bilayer membranes, self-assembling gels will open new dimensions in ionic liquid research.

CdTe nanocrystals (NCs) passivated with chiral ligands d- and l-cysteinemethylester hydrochloride were prepared and observed to exhibit characteristic CD profiles with symmetrical mirror images depending on the chirality of the capping ligand. The optical activity of CdTe NCs is shown to originate from the distorted CdS shell including chiral capping molecules. The chirality of the NC surface is maintained even after ligand exchange with an achiral thiol, providing an unprecedented chiral memory effect.

In the cascade of mammalian vision, the cis-to-trans photoisomerization reaction of the retinal chromophore bound to the opsin apoprotein acts as the first trigger for the conversion of light signals into electrical pulses, which are finally transmitted to the brain. One of the specific chemical characteristics of retinal chromophore is its high quantum yield of cis-to-trans photoisomerization, F cis-trans = 65 %, which affords the high sensitivity of the rod rhodopsin, an opsin-retinal complex required for night vision.[1] Interestingly, the F cis-trans value of retinal decreased to less than 30 % in solution without the protein. This observation suggests that the environmental conditions of the binding pocket in rhodopsin may be responsible for the high photochemical reactivity of retinal. The hydrophobic pocket in rhodopsin is thought to favor appropriate noncovalent bonding to regulate the geometry of the guest molecule in preparation for the photoisomerization reaction.[2] With the aim of developing highly efficient and sensitive photochromic molecules on the basis of the opsin-retinal system, we designed an organic photochromic molecule with a terarylene structure and demonstrated its photon-quantitative reaction.Photochromic terarylenes are composed of three aromatic rings connected to form a hexatriene backbone, [3] which is converted into a cyclohexadiene structure upon UV irradiation, as similarly observed for the photochromism of diarylethenes.[4] Recent studies on terarylenes have highlighted their high photocyclization quantum yields, which exceed 60 % [3b,d, 5] and are apparently higher than those of conventional diarylethenes.[4] Since the photoelectrocyclic reactions typically occur in less than 200 fs, the photocyclization quantum yield is generally determined by the electronic structure in the excited state, which is directly interpreted as the molecular conformation in the ground state. Diarylethenes are known to possess two conformations in solution, with the two rings in mirror symmetry (parallel conformation) or C 2 symmetry (antiparallel conformation). As the photocyclization reaction proceeds only from the C 2 -symmetrical conformation, the quantum yield is about 50 % at most.[4a] In contrast, some diarylethenes undergo a quantitative photocyclization reaction in the crystalline state, when their conformation is fixed in the antiparallel conformation and the distance between reactive carbon atoms is sufficiently short: typically less than 0.4 nm.[6] These observations indicate that the ground-state conformation plays a crucial role in the photoinduced pericyclization reaction. Therefore, various attempts have been made to regulate the ground-state geometry of diarylethenes so that they have C 2 symmetry. [7] We herein propose a concept for the design of highly reactive photochromic hexatriene molecules that is inspired by the design of foldamers; [8] thus, multiple intramolecular interactions were used to stabilize the photoreactive conformation of a terarylene.The 2,3-dithiazolylbenz...