A Stable Polyoxometalate-based Coordination Polymer for Light Driven Degradation of Organic Dye Pollutant

A new POM-based coordination polymer,[Cl_(2)Cu^(Ⅰ)_(11)(trz)_(8)][H_(3)SiW_(12)O_(40)](1),was successfully obtained under hydrothermal reaction.The compound was characterized by single-crystal X-ray diffraction,TGanalyses,IR spectra and PXRD analysis.Compound 1 shows extreme stability and outstanding catalytic activity to the degradation of organic dye pollutant.

Straightforward construction of hollow polyoxometalate-based metal-organic framework via pseudo-homoepitaxial growth

Hollow structures are significant for shortening diffusion path and promoting active center exposure.Single-crystalline hollow polyoxometalate-based metal-organic frameworks(POM@MOFs)with increased adsorption performance and catalytic activity were synthesized through a straightforward pseudo-homoepitaxial growth strategy within only 1.5 min.The strategy ingeniously exploits favorable characteristics of well-matched lattice/structure but acid stability difference between MOF and POM@MOF to construct a pseudo-homoepitaxial structure.Specifically,the MOF single crystals are used as seeds to perform epitaxial growth of the lattice/structure-matched POM@MOF under appropriate conditions.Interestingly,the MOF seeds collapse spontaneously during epitaxial growth,affording regular hollow POM@MOF single crystals.Because the acid stability of the POM@MOF is much higher than that of the MOF,it is speculated that the hollow structure formation may be related to the acid released from the epitaxial POM@MOF growth.And the pseudo-homoepitaxial POM@MOF growth strategy based on structural matching but stability difference avoids additional template removal process in conventional hollow MOF preparation and ensures hollow single crystal construction.

Polyoxovanadate-based metal-organic frameworks consisted of open vanadium sites for selective catalytic oxidation of sulfides

Three novel polyoxovanadate-based metal-organic frameworks(POV-MOFs),[Co_(2)(1,4-dtzb)_(3)]{V_(4)O_(12)}(V-Co-MOF_(1),1,4-dtzb=1,4-di(4H-1,2,4-triazol-4-yl)benzene],[Co_(3)(1,3-dtzb)_(2)][{V_(6)O_(18)}(V-Co-MOF_(2),1,3-dtzb=1,3-di(4H-1,2,4-triazol-4-yl)benzene],[Co_(4)(4,4’-bdtzb)_(2)]{V_(8)O_(24)}(V-Co-MOF_(3),4,4’-bdtzb=4,4’-(1,1’-biphenyl)-4,4’-diylbis(4H-1,2,4-triazole)benzene]were facilely synthesized and structurally characterized.Single-crystal X-ray diffraction analysis indicates that all the POV-MOFs possess open V sites lined on POV clusters of{V_(4)O_(12)}/{V_(6)O_(18)}/{V_(8)O_(24)}that uniformly distribute on the robust three-dimensional frameworks.This unique structural feature allows them to show high performance for sulfidesulfoxide transformation when performing the reaction in MeOH at 50℃ for 45 min using H_(2)O_(2) as green oxidant.Notably,V-Co-MOF1 exhibited the highest catalytic efficiency,with a conversion>99% and selectivity up to 97% for a series of sulfide substrates.Control reaction demonstrated the catalytically active centers are the open V sites while the MOF skeleton constructed from Co^(2+)and ligands also contributes to enhance the conversion and selectivity via synergistic effect.Furthermore,V-Co-MOF1 can be used as a stable heterogeneous catalyst,and both the structural integrity and catalytic performance were well reserved after five cycles,demonstrating their great potential for advanced catalytic oxidation.

Polyoxometalate-Incorporated Host-Guest Framework Derived Layered Double Hydroxide Composites for High-Performance Hybrid Supercapacitor

Metal organic frameworks have been employed as high-performance layered double hydroxide(LDH)composite supercapacitor electrode materials but have shown unsatisfactory redox ability and stability.Herein,a host-guest CuMo-based polyoxomet-alate-based metal organic framework(POMOF)with copious electrochemically active sites and strong electrochemical redox activi-ties has been effectively coupled with POM-incorporated CoNi-LDH to develop a nanocomposite(NENU-5@CoNi-LDH)by a simple solvothermal method.The designed electrode shows a high specific capacity of 333.61 mAh·g^(-1) at 1 A·g^(-1).In addition,the novel hy-brid symmetric supercapacitor NENU-5@CoNi-LDH/active carbon(AC)demonstrated a high energy density of 80.8 Wh·kg^(-1) at a power density of 750.7 W·kg^(-1).Interestingly,the nanocomposite of NENU-5@CoNi-LDH exhibits an outstanding capacitance reten-tion of 79%after 5000 charge-discharge cycles at 10 A·g^(-1).This work provides a new strategy and will be the backbone for future energy storage research.

An unprecedented dumbbell-shaped pentadeca-nuclear W-Er heterometal cluster stabilizing nanoscale hexameric arsenotungstate aggregate and electrochemical sensing properties of its conductive hybrid film-modified electrode

Cluster-based functional materials have made remarkable progress owing to their wonderful structures and distinctive physicochemical performances,one of on-going advancements of which is basically driven by synthetic chemistry of exploring and constructing novel nanosized gigantic polyoxometalate(POM)aggregates.In this article,an unprecedented nanoscale hexameric arsenotungstate aggregate Na_(9)K_(16)H_(4)[Er_(0.5)K_(0.5)(H_(2)O)_(7)][Er_(5)W10O_(2)6(H_(2)O)_(14)][B-α-AsW_(9)O_(33)]_(6)·102H_(2)O(1)has been synthesized by the combined synthetic strategy of simultaneously using the arsenotungstate precursor and simple tungstate material in a highly acidic aqueous solution.The{[Er_(5)W_(10)O_(26)(H_(2)O)_(14)][B-α-AsW_(9)O_(33)]6}31-polyanion in 1 consists of an intriguing dumbbell-shaped pentadeca-nuclear W-Er heterometal{Er_(5)W10O_(2)6(H_(2)O)_(14)}^(23+)cluster connecting six trilacunary[B-α-AsW_(9)O_(33)]^(9-)moieties,which has never been seen previously.Furthermore,through electropolymerization of 1 and pyrrole on the conductive substrate,a thickness-controllable and robust 1-PPY(PPY=polypyrrole)hybrid film was successfully prepared,which represents the first POM-PPY film assembled from high-nuclear lanthanide(Ln)encapsulated POM and PPY hitherto.The 1-PPY film-based electrochemical biosensor exhibits a favorable recognition performance for ochratoxin A in multiple media.This work not only provides a feasible combined synthetic strategy of the POM precursor and simple tungstate material for constructing complicated multi-Ln-inserted POM aggregates,but also offers a promising electrochemical platform constructed from POM-based conductive films for identifying trace biomolecules in complex environments.