Clarification of the Complexation Behaviour of 2,6-di-O-Methylated β-Cyclodextrin and Vitamin E and Radical Scavenging Ability of the Complex in Aqueous Solution.

The precise understanding of the behaviour of vitamin E (α-tocopherol; Toc) complexed with cyclodextrin (CD) additives in aqueous solution is a fundamental issue for further development of their aqua-related biological applications. In this study, the solubilisation and complexation behaviours of Toc with methyl-substituted CD derivatives and the radical scavenging ability of the resulting complexes were precisely investigated in water media. Several problems were encountered upon pre-dissolving Toc in an organic solvent prior to the addition to the water media, such as enhancement of the dispersibility and decrease in the complexation capacity.

Dual mechanoluminescence system comprising a solid-state di-copper(I) complex containing N-heterocyclic carbene ligands.

A simple N-heterocyclic carbene (NHC) ligand linked to a flexible propylene linker allows the formation of "Cu-Cu"- and "2 Cu"-type geometries inside a molecular framework. The incorporation of two Cu(i) ions in close proximity was observed in the Cu-Cu-type geometry but not in the 2 Cu-type geometry. In this study, the ground-state geometries of solid-state di-copper(i) complexes containing NHC ligands with ethyl substituents were modulated by external stimuli.

Photocatalytic CO reduction using metal complexes in various ionic liquids.

Aiming to diversify photocatalytic systems for CO2 reduction using metal complexes, this study investigated the use of various ionic liquids as reaction solvents. The photophysical properties of an Ir(iii) complex, functioning as a photosensitiser, and the photocatalytic ability of mixed systems consisting of the Ir(iii) photosensitiser and a Re(i) catalyst in twelve kinds of ionic liquids were systematically investigated by comparison with those in N,N-dimethylacetamide (DMA), which is a standard solvent for photocatalytic CO2 reduction. Even though the photophysical properties of the Ir(iii) complex in ionic-liquid solutions were quite similar to those in DMA, both the photosensitising ability of the Ir complex and the photocatalytic abilities of the systems strongly depended on the structures of the ionic liquids.