Dinuclear Triple-Stranded Helicates Composed of Tetradentate Ligands with Aluminum(III) Chromophores: Optical Resolution and Multi-color Circularly Polarized Luminescence Properties.

New chiroptical chromophores, dinuclear triple-stranded helicates, composed of tetradentate ligands with aluminum(III) ions, are described. These are synthesized in two steps using inexpensive pyrrole derivatives, hydrazine, and aluminum chloride. These molecular architectures (ALPHY) show multi-color (cyan, yellow, and orange) photoluminescence in solution and in the solid-state, which depends on the substituents of the ligands. The photoluminescence quantum yields of helicates were up to 54 %. The right-handed (P) and left-handed (M) helicates are so stable that they do not undergo racemization in some solvents and are mirror images according to circular dichroism and circularly polarized luminescence (CPL) with an absolute luminescence dissymmetry factor (glum ) of up to the 10-3 order. Mixing the different helicates produces white-light emission with CPL characters. This study offers a glimpse into the potential applications of chromophores with diverse photophysical properties.

Redetermination of di-aqua-tris-(4-oxo-pent-2-en-2-olato-κ(2) O,O')lanthanum(III).

The structure of the title compound, [La(C5H7O2)3(H2O)2], has been redetermined to modern standards with anisotropic displacement parameters for all non-H atoms and the hydrogen-bonding pattern unambiguously established [for the previous study, see Phillips et al. (1968 ▶). Inorg. Chem. 7, 2295-2299]. The La(3+) ion is coordinated by three O,O'-bidentate acetyl-acetate (acac(-)) ligands and two water mol-ecules, resulting in a fairly regular square-anti-prismatic LaO8 coordination geometry, with both aqua ligands part of the same square face. In the crystal, the neutral complex mol-ecules are linked into [110] chains by O-H⋯O hydrogen bonds.