Satoru Shimomura

Molecular decoding using luminescence from an entangled porous framework

Chemosensors detect a single target molecule from among several molecules, but cannot differentiate targets from one another. In this study, we report a molecular decoding strategy in which a single host domain accommodates a class of molecules and distinguishes between them with a corresponding readout. We synthesized the decoding host by embedding naphthalenediimide into the scaffold of an entangled porous framework that exhibited structural dynamics due to the dislocation of two chemically non-interconnected frameworks. An intense turn-on emission was observed on incorporation of a class of aromatic compounds, and the resulting luminescent colour was dependent on the chemical substituent of the aromatic guest. This unprecedented chemoresponsive, multicolour luminescence originates from an enhanced naphthalenediimide–aromatic guest interaction because of the induced-fit structural transformation of the entangled framework. We demonstrate that the cooperative structural transition in mesoscopic crystal domains results in a nonlinear sensor response to the guest concentration. Distinguishing closely related molecules using chemosensor materials is a continuing challenge. Here, an entangled porous coordination polymer is developed, which confines volatile organic compounds, and allows photoluminescence-based distinction of structurally similar aromatic molecules.

Selective sorption of oxygen and nitric oxide by an electron-donating flexible porous coordination polymer

Porous coordination polymers are materials formed from metal ions that are bridged together by organic linkers and that can combine two seemingly contradictory properties—crystallinity and flexibility. Porous coordination polymers can therefore create highly regular yet dynamic nanoporous domains that are particularly promising for sorption applications. Here, we describe the effective selective sorption of dioxygen and nitric oxide by a structurally and electronically dynamic porous coordination polymer built from zinc centres and tetracyanoquinodimethane (TCNQ) as a linker. In contrast to a variety of other gas molecules (C2H2, Ar, CO2, N2 and CO), O2 and NO are accommodated in its pores. This unprecedented preference arises from the concerted effect of the charge-transfer interaction between TCNQ and these guests, and the switchable gate opening and closing of the pores of the framework. This system provides further insight into the efficient recognition of small gas molecules. Porous coordination polymers can form materials that are both crystalline and flexible, creating regular yet dynamic channels that are promising for guest sorption. Guest selectivity is difficult to achieve, however, and typically relies on size- or shape-recognition. A framework has now been assembled that combines charge-transfer interactions and structural flexibility to only accommodate O2 and NO.

Heterogeneously Hybridized Porous Coordination Polymer Crystals: Fabrication of Heterometallic Core–Shell Single Crystals with an In-Plane Rotational Epitaxial Relationship†

MOF on MOF: Core-shell porous coordination polymer (PCP) crystals are fabricated at the single-crystal level by epitaxial growth in solution. Synchrotron X-ray diffraction measurements unveiled the structural relationship between the shell crystal and the core crystal, where in-plane rotational epitaxial growth compensates the difference in lattice constant.

Chemistry and application of flexible porous coordination polymers

Abstract Porous coordination polymers (PCPs), which are microporous materials, have been given much attention from both scientific and commercial aspects regarding their application to gas storage, gas separation and catalytic reaction because of the regularity of their pore shape and pore size, accompanied with the functionality. Moreover, in recent years, flexible PCPs, which are structurally transformable depending upon external stimuli, have been attractive because they provide unique properties, dissimilar to those of zeolites. In this review, the chemistry and application of flexible crystalline PCPs are summarized and discussed.

Enhanced selectivity of CO2 from a ternary gas mixture in an interdigitated porous framework

A flexible porous coordination polymer with interdigitated structure (CID-3) has been synthesized whose pore size and structural flexibility are suitable for CO(2) capture, providing us with highly selective adsorption properties of CO(2) from a ternary O(2), N(2) and CO(2) mixture.

Impact of Metal-Ion Dependence on the Porous and Electronic Properties of TCNQ-Dianion-Based Porous Coordination Polymers

A series of TCNQ-dianion-based porous coordination polymers [M(TCNQ)bpy] (M = Fe, Zn, Mn, Co, Cd) have been synthesized and characterized. The synthesis reactions of these compounds are promoted by the addition of ascorbic acid, which is the key to obtaining a high yield. They form almost identical three-dimensional pillared layer structures with the M-TCNQ two-dimensional layers linked by bpy pillar ligands. The electronic properties of these compounds vary depending on the constitutional metal ions and guest molecules. We found that the electronic interaction between metal ions and TCNQ moieties in the frameworks strongly impacted the electronic properties of the compounds.

Soft porous crystal meets TCNQ: charge transfer-type porous coordination polymers

The significant progress of porous coordination polymers (or metal–organic frameworks) has been attracting the attention of a lot of scientists in various disciplines and encouraging their entry into this field. The synergy of diverse scientific senses brings further spread of the chemistry of porous coordination polymers. In this review, we introduced the recent developments in PCPs resulting from the hybridization with TCNQ chemistry. Electronic and structural diversities of TCNQ provide novel and advanced porous properties, when it is hybridized with a flexible nature of porous coordination polymers.

Inclusion and dynamics of a polymer-Li salt complex in coordination nanochannels.

A complex of polyethylene glycol with LiBF(4) was incorporated into the nanochannels of a porous coordination polymer, where a liquid-like mobility of the Li ions was attained, even within the highly constrained geometry.

Porous Coordination Polymers Towards Gas Technology

Gas sorption is a key technology for solving the global issues of energy and the environment that beset the world. From the end of the twentieth century, porous coordination polymers have been synthesized and studied as candidates for advanced adsorbents with a wide variety of applications. The regular nanospace of porous coordination polymers shows unique gas molecule capture and creates a new chemistry in the field of porous materials. In this article, we focus on the gas sorption properties of porous coordination polymers. Their uniqueness is illustrated using current representative results and discussed together with perspectives on the gas technology.

Chemistry and application of porous coordination polymers

Abstrsct The porous coordination polymers (PCPs), as new functional microporous adsorbents consist of metal ions and organic ligands, have attracted the attention of chemists from the viewpoint of both scientific interest in the creation of regular nano-sized void spaces with unprecedented guest accommodation phenomena and commercial interest in their promising applications such as gas storage, molecular separation and in heterogeneous catalysis. The recent development in designing the porous framework has provided unprecedented gas sorption properties or selective guest entrapment by introducing various kinds of interaction sites; from van der Waals interaction to charge transfer interaction within the open framework.