刚性柱双π墙金属有机框架:单晶到单晶结构转换,碘富集与缓释,协同导电性研究

本文在溶剂热条件下利用刚性柱型金属手性配位链(Zn-lactate),辅助于三角架桥联配体(pybz)构筑了目前第一例高稳定性、双π墙的纳米孔道配位聚合物Zn3(pybz)2(lac)2·2.5DMF(1)。化合物1具有孔径为1.12nm×1.02nm的一维纳米通道,其孔洞率Vvoid为43.5%,Langmuir比表面积为918.5m2.g-1,热稳定性高达400°C。化合物1通过晶态转换的方式得到去客体化合物Zn3(pybz)2(lac)2(1′)。1′在碘的环己烷溶液中展现出对碘分子前所未有的超级富集与控释效果,单位碘负载量达到1g I2/g1′,同时载碘单晶在乙醇溶液中可实现碘的可控释放。由于客体I2分子与主体双壁π电子两者间交替的电荷转移,导致载碘单晶的导电性能比碘单质剧增440倍。上述研究,在国际上首次发现了绝缘性客体与绝缘性配位聚合物主体协同有序电荷转移进而导电性剧增的特殊现象。

Synthesis,Structure and Polymorphism of a Novel Two-dimensional Cobalt(Ⅱ)Coordination Polymer Constructed from Citrazinate Ligand

The polymeric Co（Ⅱ） complex[Co（Hdhpc）（py）]n（1）（py = pyridine,H3dhpc =2,6-dihydroxypyridine-4-carboxyl acid） was prepared and characterized.X-ray diffraction data revealed that the compound crystallizes in dimorphic 1α and 1β forms at room and low temperature,respectively.The former crystallizes in the orthorhombic crystal system,space group Pbcm with a =7.209（1）,b = 14.834（3）,c = 15.376（3） A°,V= 1644.3（5）A°3,Z = 4,C（16）H（13）CoN3O4,Mr = 370.22,Dc= 1.496 g/cm^3,F（000） = 756,μ = 1.068 mm^-1,R = 0.0633 and wR = 0.1192.While 1β is attributed to the monoclinic space group C2/c with a = 32.102（4）,b = 7.022,c = 14.945（2）A°,β = 109.052（5）°,V= 3184.4（6） A°3,Z= 8,Dc= 1.544 g/cm^3,F（000） = 1512,μ = 1.103 mm^-1,R = 0.0428 and wR =0.0797.The conformation changes of pyridines between Co-citrazinate planes leading to a reversible single-crystal to single-crystal transformation.The variable temperature magnetic data indicate a weak ferrimagnetism.

Magnetic-Field-Induced Strains of Bonded Ni-Mn-Ga Melt-Spun Ribbons

Non-stoichiometric Ni50Mn27 Ga23 polycrystalline ribbons are prepared by melt-spinning technique. The magneticfield-induced strain （MFIS） of Ni-Mn-Ga bulk alloy prepared by bonding the melt-spun ribbons is obtained. The experimental results show that Ni50Mn27Ga23 bonded ribbons exhibit a typical thermal-elastic shape memory effect in the thickness direction. The martensitic transformation strain of bonded ribbons is an expansive strain of about 0.3% without the magnetic field and a contractive strain of about -0.46% at the magnetic field of 1 T. The field can not only enhance the value of the martensitic transformation strain of the bonded ribbons, but can also change the direction of the strain. The bonded ribbons alloy presents negative MFIS and obtains a larger value of the strain though influenced by the adhesive between the ribbons. Therefore, the preparation technique of the Ni-Mn-Ga bulk alloy by bonding melt-spun ribbons is helpful to get rid of the size restriction of the ribbon and to broaden the applications of the ribbons.

Enhancing the singlet oxygen capture and release rate of metal-organic frameworks through interpenetration tuning

Recognized as one of the important active species involved in varicus ractions,singlet oxygen(^(1)O_(2))shows potential applications in chemical.blological,and environmental related fields.However,the con-trolled capture and release of^(1)O_(2)are still facing huge challenges due to its short lifetime and high re-activity.Herein,a framework-interpenetration tuning strategy was applied on a metal-organic framework(MOF)that aiming to improve the capture and release rate of O.The porosity of the MOF was remark-ably enhanced with the structural evolution from seven-fold(termed NKM-181)to six-fold interpene-tration(termed NKM-182),and the active anthracene sites became much mare accessible.Such drastic process can be achieved as simple as exchanging the primitive MOF in selected solvent and occurred surprisingly as single-crystal to single-crystal transformation.Also,additionally owing to the unblocked regular channels,NKM-182 shown significantly improved^(1)O_(2)trapping and releasing rates compared to strates an unprecedented regulation of^(1)O_(2)capture and release that of in NKM-181.This work demon process,along with achieving the highest^(1)O_(2)capture and release rate among reported porous materi-als.furthermore.the obtalned endoperoxides with^(1)O_(2)loaded(termed EPO-NKM-181 and EPO-NKM-182)can be used as a high efficiency smart material for anti-fake application.

Tetraolefin stereospecific photodimerization and photopolymerization in coordination polymers

In the context of the highly desirable design and preparation of smart materials with adjustable properties based on photoreactive compounds,we report two unique photoreactive coordination polymers(CPs),{[Zn(4-Iba)_(2)(4-tkpvb)]·H_()2O}_(n)(1,4-HIba=4-iodobenzoic acid,4-tkpvb=1,2,4,5-tetrakis(4-pyridylvinyl)benzene)and[Cd(1,4-bdc)(4-tkpvb)]_(n)(2,1,4-H_(2)bdc=1,4-benzenedicarboxylic acid).Depending on the metal ions and auxiliary carboxylate ligands used,the 4-tkpvb ligands in 1 and 2 adopt different mutual arrangements,which facilitate the photodimerization and photopolymerization reactions in single crystal to single crystal(SCSC)transformations.Upon UV light irradiation which results in the dimerization of the 4-tkpvb ligands,the one-dimensional(1D)zigzag chainsof 1 are transformed into a two-dimensional(2D)network of{[Zn(4-Iba)_(2)(bpbtpvcb)_(0.5)]·H_(2)O}_(n)(1a,bpbtpvcb=1,3-bis(4-pyridyl)-2,4-bis(2,4,5-tri(2-(4-pyridyl)vinyl)phenylcyclobutane).Similarly,in the crystals of 2,all 4-tkpvb ligands experience a photopolymerization reaction to form an unprecedented 1D linear organic polymer,poly-1,3-bis(4-pyridyl)-2,5-bis(2-(4-pyridyl)-vinyl)phenyl)cyclobutane(poly-bpbpvpcb).Furthermore,the 2D network of 2 is converted into a three-dimensional(3D)framework of[Cd_(n)(1,4-bdc)_(n)(poly-bpbpvpcb)](2a).This work not only offers a new protocol to selectively synthesize new supramolecular cyclic compounds,but also expands the application of photopolymerization to the synthesis of macromolecules.

Designing a Bifunctional Brønsted Acid-Base Heterogeneous Catalyst Through Precise Installation of Ligands on Metal-Organic Frameworks

A Brønsted acid-base bifunctional metal-organic framework(MOF)catalyst,PCN-700-AB[A=Brønsted acid site,TPDC-(COOH)_(2)[(1,1′∶4′,1″-terphenyl)-2,2″,4,4″-tetracarboxylic acid]and B=Brønsted basic site,BDC-NH_(2)],was designed precisely and synthesized successfully through sequential installation of Brønsted acid and base functionalities in a crystalline zirconium(Zr)-MOF.The installation underwent single-crystal-to-singlecrystal transformation throughout the process;hence,the structure of the bifunctional catalyst could be characterized accurately via single-crystal X-ray crystallography.The bifunctional MOF catalyst obtained exhibited excellent acid-base catalytic activity for a cascade of one-pot deacetalization-Knoevenagel condensation reaction.The work presented here could be considered as a promising solution to incorporate multifunctional components readily,especially the hostile aspects,into one MOF structure.