Assembling of voids gives a new opportunity of chemistry
Porosity, into which another molecule can be accommodated, gives us a new opportunity to change material properties. We are working on solid-state porous materials and on the development of “how to assemble voids” in materials. We study two distinct approaches.
Assembling of building blocks to construct framework materials:
This is a conventional and straightforward approach to build up framework materials with inherent porosity, so-called metal-organic frameworks (MOFs). Our research group have been working on this type of materials and have focused particularly on flexible MOFs with interpenetrated structures.
Assembling of preorganized porous molecules into amorphous solids:
Currently we are developing a new method to create soft materials with inherent porosity. The key protocol is first to synthesize a stable porous molecule, so-called metal-organic polyhedra (MOP), followed by assembling them into solids. This new type of materials is not necessarily cystalline but can be elastic.
空間をつなげて、新しい材料をつくる
空間・空隙・細孔、と呼ばれる何もない場所には、別の分子をつめこんで、材料そのものの性質を変えることができます。私たちは次の２つのアプローチで、固体材料の中で空間をつなげ、新しい材料をつくる研究を行っています。
分子の構築素子を集めて、フレームワーク材料をつくる：
多孔性金属錯体・多孔性配位高分子（PCP/MOF）と呼ばれる材料は、フレームワーク骨格をもつ固体材料で、本質的に空間を内包しています。特に、相互貫入構造（二つのフレームワークがお互い入れ子構造になっている）について研究をおこない、そのフレームワーク構造柔軟性を利用した機能発現に関する研究を行っています。
安定な空間をもつ分子を集めて、柔らかい固体材料をつくる：
現在、分子レベルで制御された空間を持つソフトマテリアルの創製を目指しています。分子として既に安定な空間を持つ金属錯体多面体（MOP）をうまく集合させることで、結晶性ではない弾性がある新しい固体材料をつくり、様々な分野に応用します。
<Reviews>
“Control over Flexibility of Entangled Porous Coordination Frameworks by Molecular and Mesoscopic Chemistries”
Chem. Lett. 2013, 42, 570-576.
“Emerging applications of metal–organic frameworks”
CrystEngComm 2016, 18, 6532-6542.
<Original papers>
“Periodic molecular boxes in entangled enantiomorphic lcy nets”
Chem. Commun. 2010, 46, 4142-4144.
“Molecular decoding using luminescence from an entangled porous framework”
Nature Commun. 2011, 2, 168.
“Control of the charge-transfer interaction between a flexible porous coordination host and aromatic guests by framework isomerism”
CrystEngComm 2011, 13, 3360-3363.
“Charge Transfer and Exciplex Emissions from a Naphthalenediimide Entangled Coordination Framework Accommodating Various Aromatic Guests”
J. Phys. Chem. C 2012, 116, 26084-26090.
“Trapping of a Spatial Transient State During the Framework Transformation of a Porous Coordination Polymer”
J. Am. Chem. Soc. 2014, 136, 4938-4944.
“Enhanced Phosphorescence Emission by Incorporating Aromatic Halides into an Entangled Coordination Framework Based on Naphthalenediimide”
ChemPhysChem 2014, 15, 2517–2521.
“Rhodium–Organic Cuboctahedra as Porous Solids with Strong Binding Sites”
Inorg. Chem. 2016, 55, 10843–10846.
“Switchable Gate-Opening Effect in Metal-Organic Polyhedra Assemblies Through Solution Processing”
Chem. Sci. 2018, 9, 6463-6469.
“Postsynthetic Covalent and Coordination Functionalization of Rhodium(II)-Based Metal–Organic Polyhedra”
J. Am. Chem. Soc. 2019, 141, 4094–4102.
“Hysteresis in the Gas Sorption Isotherms of Metal-Organic Cages Accompanied by Subtle Changes in Molecular Packing”
Chem. Commun. 2020, 56, 3689.
“Pseudo-5-Fold Symmetrical Ligand Drives Geometric Frustration in Porous Metal-Organic and Hydrogen Bonded Frameworks”
J. Am. Chem. Soc. 2020, 142, 13839.