Takafumi Kinuta

Control of the Solid‐State Chiral Optical Properties of a Supramolecular Organic Fluorophore Containing 4‐(2‐Arylethynyl)‐Benzoic Acid

The solid-state chiral optical properties of a 4-(2-arylethynyl)-benzoic acid/amine supramolecular organic fluorophore can be controlled by changing the arylethynyl group of the achiral 4-(2-arylethynyl)-benzoic acid component molecule rather than the chirality of the amine component molecule.

Nonclassical Tunability of Solid‐State CD and CPL Properties of a Chiral 2‐Naphthalenecarboxylic Acid/Amine Supramolecular Organic Fluorophore

The solid-state chiral optical properties (circular dichroism and circularly polarized luminescence) of a 2-naphthalenecarboxylic acid/amine supramolecular organic fluorophore can be controlled by changing the aryl unit of the chiral 1-arylethylamine component of the molecule rather than altering the chirality of the 1-arylethylamine itself.

Conformational and color polymorphism of achiral 2-methyl-3-(2-naphthalenylthio)-1,4-naphthalenedione

An achiral compound, 2-methyl-3-(2-naphthalenylthio)-1,4-naphthalenedione, shows conformational and color polymorphism, and each polymorph shows different optical properties and can be controlled by changing crystallization conditions.

Polymorphic supramolecular organic fluorophore composed of 2-naphthalenecarboxylic acid and benzylamine

By using achiral fluorescent 2-naphthalenecarboxylic acid with achiral benzylamine, three types of polymorphic supramolecular organic fluorophores with different optical properties are created. These include a racemic supramolecular fluorophore and chiral fluorophores. These polymorphic supramolecular fluorophores can be controlled by changing the crystallization method.

Preparation of novel polymorphic pigment 3,3′-(4,4′-biphenyldiylbisthio)bis-2-methyl-1,4-naphthoquinone and its polymorphic properties

The novel pigment 3,3′-(4,4′-biphenyldiylbisthio)bis-2-methyl-1,4-naphthoquinone comprising two naphthoquinone units was successfully synthesized. This pigment exhibits three conformational polymorphs, all of which have different colors (light red, red, and deep red).

Dependence of solid-state optical properties on binding groups in biphenyl acid/amine supramolecular organic complexes

Chiral carboxylic acid/amine and sulfonic acid/amine supramolecular organic complexes composed of biphenyl units were successfully prepared using achiral biphenylcarboxylic acid (or biphenylsulfonic acid) derivatives and chiral 1-phenylethylamine as component molecules. The solid-state circular dichroism (CD) and fluorescent properties of the supramolecular complexes change significantly with the type and number of binding groups.

Control of solid-state chiral optical properties of a chiral supramolecular organic fluorophore consisting of 1-pyrenesulfonic acid and chiral amine molecules

The solid-state chiral optical properties of a 1-pyrenesulfonic acid/amine supramolecular organic fluorophore could be controlled by changing the type of the aromatic ring and not the chirality of the chiral amine component molecule in the solid state.

Solid-state fluorescence host complex formed by assembly of two-dimensional layered network structure composed of 2,6-naphthalenedicarboxylic acid and 2-naphthylethylamine

A solid-state fluorescence host complex was prepared by assembly of a two-dimensional (2D) layered hydrogen- and ionic-bonded network structure composed of 2-naphthylethylamine and 2,6-naphthalenedicarboxylic acid. In this complex, the MeOH guest molecules are one-dimensionally trapped in channel-like cavities formed by the characteristic 2D layered network structures. This supramolecular host complex including MeOH shows fluorescence in the solid state.

Molecular recognition of bisphenol A and its derivatives using p-benzoquinone

By using p-benzoquinone as an electron acceptor, charge-transfer (CT) complexes with bisphenol A and its derivatives were successfully prepared by crystallization from a solution or solid-grinding crystallization. The colors of the obtained CT complexes varied with the type of bisphenol A derivative. This CT system may be used as a sensitive and visible indicator for bisphenol A derivatives.

Complexation behaviour of a CT complex composed of 9,10-bis(3,5-dihydroxyphenyl)anthracene and viologen derivatives

A chiral charge-transfer (CT) complex was formed using achiral 9,10-bis(3,5-dihydroxyphenyl)anthracene (BDHA) as an electron donor and achiral 1,1′-dimethyl-4,4′-bipyridinium dichloride (MVCl2) as an electron acceptor. This chiral CT complex can include n-alkyl alcohol molecules as guests. On the other hand, when 1,1′-diphenyl-4,4′-bipyridinium dichloride and 1,1′-dibenzyl-4,4′-bipyridinium dichloride were used as electron acceptors, achiral CT complexes without guests were formed. It was found that the chiral crystallisation of the BDHA/MVCl2–CT host system was caused by steric and electric intermolecular interactions between host component molecules BDHA and MVCl2 during crystallisation.