Chiroptical switching behavior of heteroleptic ruthenium complexes bearing acetylacetonato and tropolonato ligands.

Four types of tris-chelate ruthenium complexes bearing acetylacetonato (acac) and tropolonato (trop) ligands were synthesized and optically resolved into Δ and Λ isomers: [Ru(acac)] (Ru-0), [Ru(acac)(trop)] (Ru-1), [Ru(acac)(trop)] (Ru-2), and [Ru(trop)] (Ru-3). Chiral HPLC chromatograms, electronic circular dichroism (ECD), and vibrational circular dichroism (VCD) of the four ruthenium complexes were systematically investigated. As a result, the absolute configurations of the newly prepared enantiomeric complexes Ru-2 and Ru-3 were determined.

Hexagonal ordering of racemic Ni(II) complexes in the interlayer space of a clay mineral.

The molecular arrangement of racemic [Ni(phen)3]2+ complexes in the interlayer space of montmorillonite was investigated using X-ray diffraction measurements. When the amount of the adsorbed complexes exceeded the cation exchange capacity, they were found to form a double-molecular layer with the 2D hexagonal arrangement in the interlayer space.

Tris(tropolonato) ruthenium as a hub for connecting π-conjugated systems.

In this study, the intramolecular electronic communication between π-conjugated moieties bridged by the tris-chelate [Ru(trop)] (trop = tropolonate) framework has been investigated and compared with [Ru(acac)] (acac = acetylacetonate) derivatives. Two types of π-conjugated groups, -CSiMe and -CPh, which were each introduced at the 5-position of tropolonate, were found to behave almost independently in the resultant ruthenium complexes. In contrast, the cyclic voltammetry study of [Ru(trop)] derivatives showed a clear decrease in ΔE, the difference in the potentials of the two redox couples, with an increase in the number of π-conjugated groups introduced into the [Ru(trop)] framework.