A ditopic ligand bpy-cyclam(L)and its heterometallo-binuclear complex Ru(bpy)_2(bpy-cyclam-Ni)(ClO_4)_43H_2O(3)designed for use in the catalytic photoreduction of carbon dioxide have been newly synthesized and charact...A ditopic ligand bpy-cyclam(L)and its heterometallo-binuclear complex Ru(bpy)_2(bpy-cyclam-Ni)(ClO_4)_43H_2O(3)designed for use in the catalytic photoreduction of carbon dioxide have been newly synthesized and characterized.The protonation constants of L were also determined.展开更多
Deoxyribonucleic acid(DNA)is a biologically essential molecule that holds a genetic code.DNA also carries oxyanionic phosphate units regularly and densely along its double-stranded,helical structure.Although several s...Deoxyribonucleic acid(DNA)is a biologically essential molecule that holds a genetic code.DNA also carries oxyanionic phosphate units regularly and densely along its double-stranded,helical structure.Although several strategies have been reported to materialize DNA,the mechanical properties are not comparable to those of oil-based commodity plastics.Here,we report a DNA-based supramolecular plastic(^(DNA)SP),which is mechanically stiff yet readily dissociable into metabolizable monomers by the action of salt.We mixed oligo-DNA and a ditopic guanidinium salt(Gu_(2))serving as the anionic and cationic monomers,respectively,in deionized water,forming a cross-linked polymer network via a multivalent saltbridge interaction.This polymer network spontaneously phase-separated into a condensed phase,while the counterions of the two monomers remained in the original water-rich phase;thus,physically separated fromthe polymer network.Isolation of the condensed phase,followed by drying,formed ^(DNA)SP,a glassy,densely packed,thermally stable(T_(5%)=216°C),and optically transparent plastic,with a refractive index(n)of 1.46 and mechanical stiffness(E_(IT))of 8.2 GPa comparable to thermoset commodity polymers.One issue to address is that ^(DNA)SP is brittle,certainly due to the dense negative charges in the DNA component.展开更多
Metal-based secondary building unit and the shape of organic ligands are the two crucial factors for determining the final topology of metal-organic materials.A careful choice of organic and inorganic structural build...Metal-based secondary building unit and the shape of organic ligands are the two crucial factors for determining the final topology of metal-organic materials.A careful choice of organic and inorganic structural building units occasionally produces unexpected structures,facilitating deeper fundamental understanding of coordination-driven self-assembly behind metal-organic materials.Here,we have synthesized a triangular metal-organic polygon(MOT-1),assembled from bulky tetramethyl terephthalate and Zr-based secondary building unit.Surprisingly,the Zr-based secondary building unit serves as an unusual ditopic Zr-connector,toform metal-organic polygon MOT-1,proven to be a good candidate for water adsorption with recyclability.This study highlights the interplay of the geometrically frustrated ligand and secondary building unit in controlling the connectivity of metal-organic polygon.Such a strategy can be further used to unveil a new class of metal-organic materials.展开更多
Diffusion reaction of the labile building block Mg（acacCN）2 （acacCN= 3-cyanoacetylacetonate） with silver salts leads to a series of solvated Mg/Ag bimetallic coordination polymers with composition [Mg（acacCN）aAg...Diffusion reaction of the labile building block Mg（acacCN）2 （acacCN= 3-cyanoacetylacetonate） with silver salts leads to a series of solvated Mg/Ag bimetallic coordination polymers with composition [Mg（acacCN）aAg].solvent. Despite their common stoichiometry, the topology of these polymers depends on the solvent of crystallization. The two-dimensional coordination compound [Mg（acacCN）aAg]-4CHCl3 in space group P]- is obtained as platelet-shaped crystals from a mixture of methanol and chloroform. When kept in the reaction mixture, these thin plates within one week convert to isometric tetrahedral crystals of the 3D network [Mg（acacCN）3Ag]. 2CHC13 in the cubic space group/9213. The transformation reaction proceeds via dissolution and recrystallization. The co-crystallized solvent molecules play an important role for stabilizing the target structure： They subtend Cl...Cl contacts and interact via non- classical C-H.-. O hydrogen bonds with the coordination framework. In the new cubic coordination network, both Mg（II） and Ag（I） adopt octahedral coordination, with unprecedented face-sharing by bridging O atoms of three acetylacetonato moieties. Prolonged standing of [Mg（acacCN）3Ag]-2CHCl3 in the reaction medium leads to further degradation, under formation of [Ag（acacCN）].展开更多
文摘A ditopic ligand bpy-cyclam(L)and its heterometallo-binuclear complex Ru(bpy)_2(bpy-cyclam-Ni)(ClO_4)_43H_2O(3)designed for use in the catalytic photoreduction of carbon dioxide have been newly synthesized and characterized.The protonation constants of L were also determined.
基金financially supported by the Japan Society for the Promotion of Science(JSPS)Grant-in-Aid for Specially Promoted Research(grant no.23H05408)on“Solid-State Materials Science of Supramolecular Polymers and Their Applications”This work was also financially supported by the Rikagaku Kenkyūsho Transformative Research Innovation Platform of(RIKEN TRIP)Initiative Polymer Chemistry,Japan.Y.H.acknowledges the financial support from the Junior Research Associate(JRA)program at RIKEN for graduate students.
文摘Deoxyribonucleic acid(DNA)is a biologically essential molecule that holds a genetic code.DNA also carries oxyanionic phosphate units regularly and densely along its double-stranded,helical structure.Although several strategies have been reported to materialize DNA,the mechanical properties are not comparable to those of oil-based commodity plastics.Here,we report a DNA-based supramolecular plastic(^(DNA)SP),which is mechanically stiff yet readily dissociable into metabolizable monomers by the action of salt.We mixed oligo-DNA and a ditopic guanidinium salt(Gu_(2))serving as the anionic and cationic monomers,respectively,in deionized water,forming a cross-linked polymer network via a multivalent saltbridge interaction.This polymer network spontaneously phase-separated into a condensed phase,while the counterions of the two monomers remained in the original water-rich phase;thus,physically separated fromthe polymer network.Isolation of the condensed phase,followed by drying,formed ^(DNA)SP,a glassy,densely packed,thermally stable(T_(5%)=216°C),and optically transparent plastic,with a refractive index(n)of 1.46 and mechanical stiffness(E_(IT))of 8.2 GPa comparable to thermoset commodity polymers.One issue to address is that ^(DNA)SP is brittle,certainly due to the dense negative charges in the DNA component.
基金Korea Environment Industry&Technology Institute(KEITI)through Public Technology Program based on Environmental Policy Program,funded by Korea M inistry of Environment(MOE)(No.2018000210002)National Research Foundation(NRF)of Korea(Nos.NRF-2016R1A5A1009405,NRF-2017M3C1B4051161)D.-W.L.and H.K.acknowledge the support from the ACCEL program Japan Science and Technology Agency(JST),JPMJAC1501.J.K.acknowledges the support from NRF Grant funded by the Korean Government(No.NRF-2018H1A2A1061391-Global Ph.D.Fellowship Program).We acknowledge the Pohang Accelerator Laboratory(PAL)for 2D beamline use(2019-1st-2D-038).We would like to thank Hyeonsoo Chofor providing 3D models for possible structures shown in Fig.8.
文摘Metal-based secondary building unit and the shape of organic ligands are the two crucial factors for determining the final topology of metal-organic materials.A careful choice of organic and inorganic structural building units occasionally produces unexpected structures,facilitating deeper fundamental understanding of coordination-driven self-assembly behind metal-organic materials.Here,we have synthesized a triangular metal-organic polygon(MOT-1),assembled from bulky tetramethyl terephthalate and Zr-based secondary building unit.Surprisingly,the Zr-based secondary building unit serves as an unusual ditopic Zr-connector,toform metal-organic polygon MOT-1,proven to be a good candidate for water adsorption with recyclability.This study highlights the interplay of the geometrically frustrated ligand and secondary building unit in controlling the connectivity of metal-organic polygon.Such a strategy can be further used to unveil a new class of metal-organic materials.
文摘Diffusion reaction of the labile building block Mg（acacCN）2 （acacCN= 3-cyanoacetylacetonate） with silver salts leads to a series of solvated Mg/Ag bimetallic coordination polymers with composition [Mg（acacCN）aAg].solvent. Despite their common stoichiometry, the topology of these polymers depends on the solvent of crystallization. The two-dimensional coordination compound [Mg（acacCN）aAg]-4CHCl3 in space group P]- is obtained as platelet-shaped crystals from a mixture of methanol and chloroform. When kept in the reaction mixture, these thin plates within one week convert to isometric tetrahedral crystals of the 3D network [Mg（acacCN）3Ag]. 2CHC13 in the cubic space group/9213. The transformation reaction proceeds via dissolution and recrystallization. The co-crystallized solvent molecules play an important role for stabilizing the target structure： They subtend Cl...Cl contacts and interact via non- classical C-H.-. O hydrogen bonds with the coordination framework. In the new cubic coordination network, both Mg（II） and Ag（I） adopt octahedral coordination, with unprecedented face-sharing by bridging O atoms of three acetylacetonato moieties. Prolonged standing of [Mg（acacCN）3Ag]-2CHCl3 in the reaction medium leads to further degradation, under formation of [Ag（acacCN）].
