Keisuke Kishida

Dense Coordination Network Capable of Selective CO2 Capture from C1 and C2 Hydrocarbons

We elucidated the specific adsorption property of CO(2) for a densely interpenetrated coordination polymer which was a nonporous structure and observed gas separation properties of CO(2) over CH(4), C(2)H(4), and C(2)H(6), studied under both equilibrium and kinetic conditions of gases at ambient temperature and pressure.

A redox-active columnar metallomesogen and its cyclic voltammetric responses

We demonstrate a strategy that appears particularly well suited for the design of redox-active liquid crystals and also constitutes the first demonstration of cyclic voltammetric responses of a metallomesogen in the columnar liquid crystalline phase.

Chromic behaviors of hexagonal columnar liquid crystalline platinum complexes with catecholato, 2-thiophenolato, and benzenedithiolato.

Liquid crystalline (LC) platinum(II) complexes with 1,2-thiophenolato and 1,2-benzendithiolato have been newly synthesized and investigated by spectroscopy together with the catecholato analogue. The variations in coordinating atoms (O or S or O/S mixed) lead to significant modulation in electrochemical properties in solution and absorption and emission properties of the complexes both in solution media and in the condensed phases. The asymmetric, polar mesogens/chromophores consisting of Pt(II), redox-active ligands, and alkyl-substituted bipyridine commonly play important roles not only in stabilizing the columnar LC phases, but also in fluctuations of the ground state energies. A key finding of the present work is the chromic properties of LC complexes induced by the interplay of self-association of the mesogens/chromophores and their fluctuating properties.

Recognition of 1,3-Butadiene by a Porous Coordination Polymer

The separation of 1,3-butadiene from C4 hydrocarbon mixtures is imperative for the production of synthetic rubbers, and there is a need for a more economical separation method, such as a pressure swing adsorption process. With regard to adsorbents that enable C4 gas separation, [Zn(NO2 ip)(dpe)]n (SD-65; NO2 ip=5-nitroisophthalate, dpe=1,2-di(4-pyridyl)ethylene) is a promising porous material because of its structural flexibility and restricted voids, which provide unique guest-responsive accommodation. The 1,3-butadiene-selective sorption profile of SD-65 was elucidated by adsorption isotherms, in situ PXRD, and SSNMR studies and was further investigated by multigas separation and adsorption-desorption-cycle experiments for its application to separation technology.

Soft 2D Layer Porous Coordination Polymers with 1,2-Di(4-pyridyl)ethane

Porous coordination polymer compounds consisting of Zn2+, 1,2-di(4-pyridyl)ethane, and dicarboxylates were synthesised and their crystal structures were determined. These are doubly interpenetrated 2D layer structures, and the flexibility of porous structures is dependent on the substituent group of the dicarboxylate. From gas adsorption studies, distinct adsorption isotherms were observed for CO2, CH4, C2H4, and C2H6 at 195 K and 273 K, respectively.