Yumihiko Yano

Effect of hydroxyl groups in receptors bearing disulfonamide on anion recognition in acetonitrile-d3

To elucidate the roles of hydroxyl group on anion-recognition chemistry, receptors bearing disulfonamide and hydroxyl groups were prepared and their anion-binding properties were evaluated in acetonitrile.

SELECTIVE RECOGNITION FOR HEAVY AND TRANSITION METALS BY NOVEL POLYETHERS BEARING BIPYRIDINES, AND MOLECULAR CHIRALITY OF PSEUDOCROWN STRUCTURE IN THE CU(I) COMPLEX

Abstract Bisbipyridine derivatives linked by polyether chain 1 showed selective binding behavior to Zn(II) and Cu(I). The strength of the affinity is larger than that of 6, 6′-dimethylbipyridine derivative 2 because of the chelate effect of 1 . Molecular chirality of the pseudocrown ether, 1 -Cu(I)complex, was observed by 1H NMR spectroscopy at −28°C in the presence of Pirkles reagent.

HIGHLY SELECTIVE TRANSPORT OF AG+ BY A MACROBICYCLIC HOST CONTAINING A BIPYRIDINE MOIETY

Abstract A macrocyclic polyether bridged by 2,2′-bipyridine group was synthesized and found to exhibit a very high Ag + ion selectivity compared to heavy metal ions in transport through an organic liquid membrane.

Synthesis of 2,6-diamidopyridine derivatives and their functions as flavin receptors in chloroform

It has been found that 2,6-diamidopyridine derivatives act as flavin receptors by a triple hydrogen bond towards a uracil moiety of an isoalloxazine ring in CHCl3. The association constants were determined by 1H NMR (in CDCl3) and fluorescence (in CHCl3) spectroscopies; the largest is ca.103 mol–1 dm3. The triple hydrogen bond toward C(2)O, N(3)–H and C(4)O of the isoalloxazine ring was found to enhance slightly the oxidation activity in CHCl3.

Oxiran formation in the base-catalysed reaction of long-chain alkyldimethylsulphonium salts and carbonyl compounds in benzene–water

Oxirans can be sfynthesized in high yields, lby stirring a hetrerogeneous mixture of lauryldiemthylsulphonium salt and a carbonyl compound in benzene–aqueous sodium hydroxide at room temperature.

Artificial Flavin Receptors: Effects of Hydrogen Bonding on Redox Properties of a Flavin Mimic

This review describes the roles of hydrogen bonding on the redox properties of a flavin mimic by using artificial flavin receptors. The receptors exploited are melamine derivatives bearing guanidinium ion(s) that strongly bind 6-azaflavin through five or seven hydrogen bonds involving N(1), C(2)=O, N(3)-H, C(4)=O, N(5), and N(6) positions in CHCl3 and CHCl3-acetonitrile. It has been shown that receptors are quite useful for examination of the hydrogen bonding effects on the redox potential, stability of the anionic semiquinone radical, and the oxidation activity of 6-azaflavin. The functionalized receptors have a substrate- or a metal-binding site have been shown to facilitate the reactions by forming the noncovalent assemblies. A possibility as an apoprotein model of the receptors has been mentioned also.

Pseudothiacrown and pseudothiolariat ethers for double recognition systems toward copper(I) and silver(I)

Linear and branched polythioethers with bipyridine moieties at the termini bind Cu(I) to afford pseudothiacrown and pseudothiolariat ethers by conformational change of the polyether chain, and the pseudocrowns extract Ag(I) selectively

Remarkably selective binding of silver ion by thiolariat ether with a 15-crown-5 ring

The thiolariat ether, which is a lariat ether with an oxygen atom in the side arm replaced by a sulfur atom, exhibits a high selectivity to silver ion among alkali and heavy metal ions because of synergistic ligation of the crown ether and the one sulfur outside the ring.

A flavin receptor. Strong binding ability of a melamine derivative bearing a guanidinium ion for 6-azaflavin: five hydrogen bonds formed in chloroform

A melamine derivative bearing a guanidinium ion strongly binds 6-azaflavin via five hydrogen bonds with a binding constant of 140 000 mol–1 dm3 in CHCl3.

Synthesis of Crown Ethers Containing a Sulfide Group Inside the Ring and High Ag+ Selectivity in Solvent Extraction

Crown ethers bearing a sulfide, a sulfoxide, or a sulfone group inside the ring have been prepared and the sulfide derivatives exhibit a significantly high Ag + selectivity in solvent extraction