Cyclodextrins (CDs) are water-soluble host compounds having nano-size hydrophobic cavities that enable them to incorporate organic molecules in water. Optically inert CDs can be efficiently combined with various types of chromoionophores and fluoroionophores. In this study, using diverse combinations of phenylboronic acid fluorescent sensors and azoprobes with CDs, the unique saccharide recognition functions of CD, chemically modified CD, and CD gel complexes based on their synergistic function are clarified, thereby confirming their use as supramolecular saccharide sensors. To realize novel supramolecular chirality, the twisted structure of two ditopic azoprobes inside the γ-CD chiral cavity is controlled by multi-point recognition of guest ions in water. As different types of supramolecular saccharide sensors, phenylboronic acidbased self-assembling systems are also reviewed.

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DNA/RNA duplexes containing metal-ionmediated base pairs (metallo-base pairs) have potential applications in developing nucleic acid-based nanodevices and genetic code expansion. Many metallo-base pairs are formed within duplexes stabilized by Watson-Crick base pairs. Recently, the crystal structure of an Ag I -DNA nanowire with an uninterrupted one-dimensional silver array was determined. Here, we present a new DNA helical wire, the "Ag I -DNA rod", containing an uninterrupted array of 11 Ag I ions. The Ag I -DNA rod consisted of only C-Ag I -C, G-Ag I -G, G-Ag I -5bromouracil ( Br U), and Br U-Ag I -Br U metallo base pairs, with no Watson-Crick pairs. The Ag I -DNA rods were connected by non-canonical G-G pairs in crystals. Notably, data from our absorbance, circular dichroism, nuclear magnetic resonance, and mass spectrometry analyses suggested that the Ag I -DNA rods formed in solution, as well as within crystals.DNA can be used as a basic template to generate functional molecules, precise molecular architectures, and nanoscale devices. [1] Recently, duplexes containing metal ion-mediated base pairs (metallo-base pairs) have been characterized. [2] Investigations of the metal-mediated pairing of natural and artificial bases have considerably expanded the design space for developing functional DNA molecules. [2] For example, metallo-base pair-forming oligonucleotides have been applied to develop DNA molecular devices such as ion-sensors, [3] electric transport nano-wires, [4] and DNA magnets. [5] Short oligonucleotides and metal ions can be mixed together to form metallo-base pairs, generating relatively small double-helical and triple-helical structures containing both metallo-base pairs and Watson-Crick base pairs. [2] Recently, the structures of short duplexes containing metal-lo-base pairs have been determined, [2] including the crystal structures of metallo-base pair duplexes composed of artificial and natural bases. [6] Heteronuclear multidimensional nuclear magnetic resonance (NMR) has also been applied to resolve the structures of metallo-base pairs in solution. [7] Recently, two types of metal-DNA nanowire have been generated in crystal form. [6f,g] Crystals containing long Ag I -DNA nanowires with uninterrupted one-dimensional silver arrays were generated by mixing short oligonucleotides with Ag I ions. [6f] In the presence of Ag I ions, the short oligonucleotides formed double-helical structures comprising only metallo-base pairs and sticky 5'-ends. The short double-helical structures were then linked together to form long Ag I -DNA nanowires, in which the Ag I ions were precisely aligned to form one-dimensional silver arrays. The second type of metal-DNA wire structure comprised Hg IImediated T : T and T : G base pairs and water-mediated C : C base pairs; this structure was observed in crystals produced by mixing the short oligonucleotide 5'-d(TTTGC)-3' with Hg II ions. [6g] Neither the Ag I -DNA nor Hg II -DNA wires contained Watson-Crick base pairs. These metallo-DNA wire structures were pre...

We synthesized novel PET (photoinduced electron transfer)-type fluorescence glucose probe 1 [(4-(anthracen-2-yl-carbamoyl)-3-fluorophenyl)boronic acid], which has a phenylboronic acid (PBA) moiety as the recognition site and anthracene as the fluorescent part. Although the PBA derivatives dissociate and bind with sugar in the basic condition, our new fluorescent probe can recognize sugars in the physiological pH by introducing an electron-withdrawing fluorine group into the PBA moiety. As a result, the pKa value of this fluorescent probe was lowered and the probe was able to recognize sugars at the physiological pH of 7.4. The sensor was found to produce two types of fluorescent signals, monomer fluorescence and dimer fluorescence, by forming a supramolecular 2:1 complex of 1 with glucose inside a γ-cyclodextrin (γ-CyD) cavity. Selective ratiometric sensing of glucose by the 1/γ-CyD complex was achieved in water at physiological pH.