Anomalous enhancement of proton conductivity for water molecular clusters stabilized in interstitial spaces of porous molecular crystals.

In an investigation into the proton conductivity of crystallized water clusters confined within low-dimensional nanoporous materials, we have found that water-stable nanoporous crystals are formed by complementary hydrogen bonding between [Co(III) (H2 bim)3 ](3+) (H2 bim: 2,2'-biimidazole) and TATC(3-) (1,3,5- tricarboxyl-2,4,6-triazinate); the O atoms in the -COO(-) groups of TATC(3-) in the porous outer wall are strongly hydrogen bonded with H2 O, forming two types of WMCs (water molecular clusters): a spirocyclic tetramer chain (SCTC) that forms infinite open 1D channels, and an isolated cyclic tetramer (ICT) present in the void space. The ICT is constructed from four H2 O molecules as a novel C2 -type WMC, which are hydrogen bonded with four-, three-, and two-coordination spheres, respectively. The largest structural fluctuation is observed at elevated temperatures from the two-coordinated H2 O molecules, which begin to rapidly and isotropically fluctuate on heating. This behavior can be rationalized by a simple model for the elucidation of pre-melting phenomena, similar to those in ice surfaces as the temperature increases. Moreover, high proton conductivity of SCTCs (ca. 10(-5) S cm(-1) at 300 K with an activation energy of 0.30 eV) through a proton-hole mechanism was observed for pellet samples using the alternating impedance method. The proton conductivity exhibits a slight enhancement of about 0.1×10(-5) S cm(-1) at 274 K due to a structural transition upon approaching this temperature that elongates the unit cell along the b-axis. The proton-transfer route can be predicted in WMCs, as O(4) of an H2 O molecule at the center of an SCTC shows a motion that rotates the dipole in the b-axis direction, but not the c-axis; the thermal ellipsoids of O(4) based on anisotropic temperature factors obtained by X-ray crystallography reflect a structural fluctuation along the b-axis direction induced by [Co(III) (H2 bim)3 ](3+) .

Description of a new species of Sternomoera (Crustacea: Amphipoda: Pontogeneiidae) from Japan, with an analysis of the phylogenetic relationships among the Japanese species based on the 28S rRNA gene.

A new species of amphipod, Sternomoera morinoi Tomikawa and Ishimaru, is described from subterranean aquatic habitats in Shiga Prefecture, Japan. In addition, Relictomoera tsushimana (Uéno, 1971) from a well on the island of Tsushima in Japan is transferred to Sternomoera and redescribed based on the holotype. Sternomoera morinoi sp. nov. is most similar to S. tsushimana (Uéno, 1971) comb, nov., but is distinguished by having many fine setae on the body, a shorter antenna 1, fewer C-setae on mandibular palp article 3, a shorter mandibular palp article 3, sparsely setose anterior margins of coxae 1-4, a different armature of the palmar margins of gnathopods 1 and 2, and no long setae on the posterior margin of the basis in gnathopod 2 and pereopods 3 and 4. The phylogenetic relationships among the Japanese species of Sternomoera are also estimated, based on partial DNA sequences of the nuclear 28S rRNA gene.

Structures and phase transition of multi-layered water nanotube confined to nanochannels.

We placed nanometer-scale water-tube clusters with phase transition within a porous crystal formed from molecular blocks specifically designed to investigate the molecular dynamics of confined water molecules.

Molecular dynamics and residual entropy in the soft crystal, SmE phase, of 4-butyl-4'-isothiocyano-1,1'-biphenyl.

Molecular dynamics and resulting disorder in the soft crystal, smectic E (SmE) phase, were studied in detail for the title compound, 4-butyl-4'-isothiocyano-1,1'-biphenyl (4TCB), by (1)H NMR spectroscopy and adiabatic calorimetry. The ordered crystal phase of 4TCB was realized for the first time under ambient pressure after long two-step annealing and used as the reference state in the analysis of the experimental results. Four motional modes were identified in the SmE phase through the analysis of the (1)H NMR T(1). The residual entropy was determined as ca. 6 J K(-1) mol(-1). This magnitude implies that most of the disorder in the SmE phase at high temperatures is removed on cooling except for the head-to-tail disorder of the rod-shaped 4TCB molecule. Standard thermodynamic functions are tabulated below 375 K.