Fumio Hamada

A highly sensitive probe detecting low pH area of HeLa cells based on rhodamine B modified β-cyclodextrins

Two kinds of rhodamine modified beta-cyclodextrins (R-1 and R-2), which are coupled up ethylene diamine (EDA) and tetraethylene pentamine (TEPA) between Rh B and beta-cyclodextrin, respectively, have been synthesized. R-1 and 2 work as a new fluorogenic probe for monitoring pH of Hela cells, and MTT of assay R-1, R-2, and rhodamine B indicate that less a cytotoxicity of those R-1 and R-2 than that of rhodamine B, where R-1 has much less one than that of R-2. The fluorogenetic probe capability of R-2 was recognized in an area of acidic area in living cell, which is lysosome.

Metal sensor of water soluble dansyl-modified thiacalix[4]arenes

Abstract The water soluble thiacalix[4]arene derivatives, which are modified with di- and tri-dansyl moieties,have been prepared to investigate their metal sensing abilities in aqueous solution. It is the first example that water soluble thiacalix[4]arene derivatives can detect metal cations directly in aqueous solution by variation of fluorescence intensity upon addition of a metal cation.

Calixarenes as enzyme models

Abstract A review of the progress towards the use of calixarenes as enzyme models is presented. Double recognition of a substrate is illustrated with the crystal structure of (H3O+)[La(ONC5H5)2(H2O)6(p-sulfonatocalix[4]arene)]−·6.5H2O, 1. The binding of zinc to calixarenes in a second-sphere fashion is shown with the crystal structure of Na2[Zn(H2O)4(ONC5H5)2][calix[4]arene]·8.5H2O, 4. The preparation and structures of aminomethylcalix[4]arenes are demonstrated with [p-(4-(2-pyridyl)piperidinomethyl)calix[4]arene], 5, and [p-(4-phenylpiperidinomethyl)calix[4]arene], 6.

Excimer formation in inclusion complexes of modified cyclodextrins

Abstract A β-cyclodextrin derivative, which possesses a polyether chain with a naphthyl moiety at its end, shows excimer emission in its concentrated solutions. The excimer was suggested to be formed between the two naphthyl moieties included in the long cylindrical cavity of the cyclodextrin dimer.

The Synthesis and X-Ray Structure of 1,2,3,4-Cyclobutane Tetracarboxylic Dianhydride and the Preparation of a New Type of Polyimide Showing Excellent Transparency and Heat Resistance

Some polyimide films based on cyclobutane-1,2,3,4-tetracarboxylic dianhy- dride (CBDA) and aromatic diamines were synthesized to investigate their temperature resistance and percent transmission of light. The preparations of CBDA were investi- gated; they produced almost 10 times the yield of CBDA in comparison to yields obtained by previous methods. The configuration of CBDA was determined by X-ray analysis to be cis-trans-cis. The polymer films showed excellent thermal resistance and were transparent and colorless, desirable characteristics for practical applications in the field of polymer engineering. However, the polymer obtained from a pyromellitic dianhydride instead of from CBDA was deep yellow and not desirable for high-qualified display materials such as liquid-crystal displays. The percent transmission of the polymers obtained from CBDA and aromatic diamines ranged from 81.5 to 85.8%, whereas the deep-yellow polymers showed low percent transmissions ranging from 48 to 63.9%.

Supramolecular assemblies of calix [4] arenes organized by feeble forces

Abstract X-ray crystallographic investigations have shown that dimeric supramolecular assemblies of water-soluble calix[4]arenes are formed by a combination of hydrophobic effects and either hydrogen bonding or secondary bonding. For Na4(pyridinium)[calix[4]arene sulfonate] · 8H2O, a dimeric arrangement based on hydrogen bonding and hydrophobic effects is found. The compound crystallizes in the monoclinic space group P21/n with a = 11.873(3), b = 24.345(6), c = 14.846(3) A, β 96.78(2)°, and Dc = 1.66 g cm−3 for Z = 4. Refinement based on 3492 observed reflections led to a final R value of 0.051. For [Cu(NC5H5)2(H2O)3](Na)3[calix[4]arene sulfonate] · 13 H2O, the dimeric association is based on a secondary bonding interaction between the copper(II) ion and a sulfonate oxygen atom combined with hydrophobic interactions. The compound crystallizes in the monoclinic space group P21/n with a = 14.672(3), b = 25.577(5), c = 15.457(3) A, β = 101.94(4)°, and Dc = 1.55 g cm−3 for Z = 4. Refinement based on 3602 obse...

Tight inclusion of an acid guest into the cavity of cyclodextrin bearing an amino moiety in dimethyl sulfoxide

Abstract Circular dichroism measurements show that β-cyclodextrin with an amino moiety has a strong binding ability for ferrocenecarboxylic acid in dimethyl sulfoxide via an acid-base interaction.

Liquid-liquid extraction of transition and alkali metal cations by a new calixarene: Diphenylphosphino calix[4]arene methyl ether

The liquid-liquid extraction of various metal ions by a diphenylphosphino calix[4]arene (1) using picrate counter ion has been studied and compared with those ofp-tert-butyl-calix[4]arene methyl ether (2) and triphenylphosphine (3). The calixarene 1 shows strong binding ability to almost all metal cations examined, but calixarene 2 shows little ability to extract any of them. Based on the continuous variation method, calixarene 1 formed 1: 2 complexes with copper(II) ion.

Dansyl-Modified γ-Cyclodextrin as a fluorescent sensor for molecular recognition

Dansyl-Modified γ-Cyclodextrin (1) has been prepared as a sensor for detecting organic compounds.1 shows pure monomer fluorescence whose intensity is decreased or enhanced upon addition of guest species. The value ΔI/I0, whereI andI0 are fluorescence intensities in the presence and absence of a guest and ΔI isI0−I, was used as a parameter of sensitivity.1 exhibits highly sensitive and selective molecular recognition ability, particularly, for ursodeoxycholic acid, chenodeoxycholic acid, and lithocholic acid.

Supramolecular assemblies based on calixarenes

Supramolecular assemblies have been constructed from calixarenes and organic molecules or ions, from calixarenes and transition metal coordination complexes, and from calixarenes themselves. Two-component systems, or host-guest complexes, are now common, but we report here the assembly of four-component super-molecules and aggregates as large as two transition metal complexes and six calix[4larenes have been characterized crystallographically. Supramolecular chemistry deals with the construction of large structures from small building blocks. These building blocks are generally held together by weak (non-covalent) interactions. This discussion will deal with calix[4larenes and with transition metal coordination complexes as the units upon which larger structures are based. The organizational principle is the assembly of second-sphere coordination complexes.