Ca2+- and Ba2+-selective receptors based on site-selective transmetalation of multinuclear polyoxime-zinc(II) complexes

Ca2+-selective recognition was achieved by using the site-selective transmetalation of homotrinuclear metallohost [L1Zn3]2+ containing a linear tetraoxime ligand. The selectivity (log(KCa/KMg) > 5.1) is comparable to those of the excellent Ca2+ receptors or sensors such as BAPTA, Quin2, and K23E1. X-ray crystallography revealed that the Ca2+ complex [L1Zn2Ca]2+ has a helical structure. On the other hand, the larger analogue H6L2 gave a mixture of [L2Zn4]2+ isomers, which selectively recognizes Ba2+ to give a single tetranuclear complex, [L2Zn3Ba]2+.     

Ir-catalyzed almost perfect enantioselective synthesis of helical polyaryls based on an axially-chiral sequence

Ir-catalyzed enantioselective [2 + 2 + 2] cycloaddition of tetraynes or an octayne with monoalkynes proceeded to give helically-chiral quinquearyl and noviaryl compounds, which respectively have four and eight consecutive axial chiralities, in an almost enantiomerically pure form.     

Synthesis of possible metabolites of chlorpromazine. I. 7-hydroxy derivatives of chlorpromazine,nor1-chlorpromazine and nor2-chlorpromazine

The title compounds and various derivatives have been prepared as analytical standards for the identification of chlorpromazine metabolites in biological materials. Additional evidence is presented for the existence of a halogen-induced Smiles rearrangement in the phenothiazine series.     

New fluorophores with rod-shaped polycyano pi-conjugated structures: synthesis and photophysical properties

[reaction: see text] Novel rod-shaped polycyano-oligo(phenyleneethynylene)s were synthesized by Pd cross-coupling reaction. Polycyano groups were found to greatly improve the emission efficiency (Phi(f)) of OPEs. By the end donor modification, we achieved the creation of very intense blue light-emitting fluorophore with the SMe group (Phi(f) = 0.972, log epsilon 4.89, lambda(em) 455 nm) and very intense yellow light-emitting fluorophore with the NMe(2) group (Phi(f) = 0.999, log epsilon 4.75, lambda(em) 555 nm). Contrasting Phi(f) solvent dependency of 6 and 7 and a linear relationship between Phi(f) and sigma(p)-X over the whole region of sigma(p)-X were also found.     

Guest-dependent inversion rate of a tetranuclear single metallohelicate

Complexation of linear hexaoxime ligand H6L with Zn2+ and Mn+ (= La3+, Ba2+) afforded a tetranuclear single metallohelicate [LZn3M]n+, whose inversion rate can be modulated by the central metal Mn+.