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POMs-based coordination polymers are promising materials for their potential application in the fields of proton conduction, catalysis and magnetism. Three new coordination polymers namely, {[Co 2 (bib) 3 (H 2 O) 2 (H 4 W 12 O 40)]·7H 2 O} n (1), {[Zn 3 (bib) 8 (H 3 ZnW 12 O 40) 2 ]·12H 2 O} n (2) and {[Ag 5 (bib) 5 (H 3 W 12 O 40)]·5H 2 O} n (3) were synthesized under hydrothermal conditions based on linear nitrogen heterocyclic ligand 1,4-bis(1-imidazolyl)benzene (bib). In compound 1 , CoII ions are linked with [H 4 W 12 O 40 ]4– anions to form a planar network and can be simplified as kgd topology, which are further linked with bib ligands to form a 3D framework. Zn2 ions of compound 2 alternately connect with bib ligands and [H 3 ZnW 12 O 40 ]3– anions to form 1D chain structure, while Zn1 ion forms isolated unit with three bib ligands and one [H 3 ZnW 12 O 40 ]3– anion, and a 3D framework is finally constructed through π ... π stacking interactions. In compound 3 , the 3D structure is constructed from a number of 1D chains formed by AgI ions and bib ligands in different directions through π ... π stacking interaction and Ag⋯O weak connection. The proton conductivity of 1 – 3 are 2.03 ​× ​10−5, 1.04 ​× ​10−6 and 1.87 ​× ​10−4 ​S ​cm−1 at 98% RH and 358 ​K, respectively. In addition, compounds 1 – 3 exhibit photocatalytic degradation capacity towards RhB and compound 1 displays antiferromagnetic behavior. Three Keggin POM-based coordination polymers have been prepared under hydrothermal condition and characterized by single-crystal X-ray diffraction, IR, XRD and TGA. The highest proton conductivity of 3 is up to 1.87 ​× ​10−4 ​S ​cm−1 at 358 ​K and 98% RH. [Display omitted] • Three Keggin POM-based coordination polymers have been prepared under hydrothermal condition. • Their structures were characterized by single-crystal X-ray diffraction, IR, XRD and TGA. • The highest proton conductivity of 3 is up to 1.87 ​× ​10−4 ​S ​cm−1 at 358 ​K and relative humidity of 98% RH. [ABSTRACT FROM AUTHOR]

The functional design of efficient and stable proton exchange membrane materials is an important research direction in the field of proton exchange membrane fuel cells (PEMFCs). In this work, ammonia molecules were successfully encapsulated into the one-dimensional pores of MOF-74(Co) through fumigation with ammonia vapor. Alternating current (AC) impedance tests showed that the proton conductivity of NH 3 modified NH 3 @ MOF-74(Co) reaches an impressive value of 6.8 × 10−3 S/cm, being 10000 times that of the pristine MOF-74(Co) at 98% relative humidity (RH) and 50 °C. Various and abundant hydrogen bonds can improve the proton conduction of NH 3 modified compound. This strategy provides an efficient and convenient way to construct high proton conducting porous MOFs materials by attaching NH 3 molecules. [Display omitted] • Ammonia molecules were successfully encapsulated into the pores of MOF-74(Co) through fumigation with ammonia vapor. • The proton conductivity of NH 3 @ MOF-74(Co) reaches the maximum value of 6.8 × 10−3 S/cm, which is 10000 times that of the pristine MOF-74(Co) at same conditions. • This strategy provides an efficient and convenient way to construct high proton conducting porous MOFs materials. [ABSTRACT FROM AUTHOR]

Herein, the postsynthetic ligand exchange process was adopted to construct a series of 1,4-naphthalenedicarboxylic acid (H 2 NDC) and 6-sulfonate-1,4-naphthalenedicarboxylic acid (H 3 SNDC) based Zr(IV)-MOFs (Zr-(NDC) x (SNDC) 1-x). This strategy anchored functional sulfonic acid groups in the pore of the MOFs. Among them, Zr-(NDC) 0.3 (SNDC) 0.7 exhibited outstanding proton conductivity of 3.18 ✕ 10−4 S cm−1 at 90 °C and 98% relative humidity (RH), which was approximately three orders of magnitude greater than that of pristine Zr-NDC. This work demonstrated a facile in situ ligand exchange approach for constructing functional group modified MOFs with high proton conductivity. [Display omitted] • A series of 1,4-naphthalenedicarboxylic acid (H 2 NDC) and 6-sulfonate-1,4-naphthalenedicarboxylic acid (H 3 SNDC) based Zr(IV)-MOFs were synthesized. • The functional sulfonic acid groups were anchored in the pore of the MOFs by ligand exchange approach. • Zr-(NDC) 0.3 (SNDC) 0.7 demonstrated remarkable proton conductivity of 3.18 × 10−4 S cm−1 at 90 °C and 98% relative humidity (RH). [ABSTRACT FROM AUTHOR]

Proton exchange membrane (PEM) is one of the core materials which were widely used in the field of fuel cells (FCs). In recent years, the metal organic frameworks (MOFs) and polymer composite membranes as tunable proton-conducting materials have showed great potential in this field. Herein, a Cu(II)-based metal organic framework (Cu-MOF) with acid/base stability was introduced into poly(vinylpyrrolidone)/poly(vinylidene fluoride) (PVP/PVDF, PP) to fabricate hybrid membranes(Cu-MOF@PP-X, where X is the % Cu-MOF content). The effects of Cu-MOF loading amounts on the conductive behavior of Cu-MOF@PP-X composites have been documented. It is worth noting that Cu-MOF@PP-50 exhibited the proton conductivity up to 4.36 ​× ​10−4 ​S ​cm−1 at 353 ​K and 98% relative humidity (RH). In addition, the value of proton conduction is about two orders of magnitude higher than that of the parent Cu-MOF (1.91 ​× ​10−6 ​S ​cm−1). This work contributes to driving further advances of MOF/polymer composites in proton-conducting apparatus. [Display omitted] • A Cu-MOF with acid/base stability was introduced into polymers (PVP/PVDF, PP) to fabricate hybrid membranes. • The effects of Cu-MOF loading amounts on the conductive behavior of Cu-MOF@PP-X composites have been documented. • Cu-MOF@PP-50 exhibited a super protonic conductivity up to 4.36 ​× ​10−4 ​S ​cm−1 at 353 ​K and 98% relative humidity (RH). • The value of proton conduction of Cu-MOF@PP-50 is about two orders of magnitude higher than that of the parent Cu-MOF. [ABSTRACT FROM AUTHOR]

A new 3D anionic metal-organic framework material, namely, [Me 2 NH 2 ] 2 [Cd 3 (L)]·2H 2 O (1 , H 4 L ​= ​2,5′-di(3′,5′-dicarboxylphenyl)pyridine) has been synthesized under solvothermal conditions and characterized by single crystal X-ray diffraction, PXRD, thermogravimetric analysis and proton conduction investigation. In 1 , the adjacent Cd(II) ions are joined to form a trinuclear [Cd 3 (COO) 8 ] secondary building unit (SBU) by eight bridging carboxylate groups of L4− ligands. The trinuclear [Cd 3 (COO) 8 ] SBUs are connected by L4− ligands into a 3D (4,8)-connected framework with 1D channels. Most interestingly, due to the guest [Me 2 NH 2 ]+ cations, water molecules and carboxylates sites are lined the pore channels, 1 possesses a remarkable proton conductivity of 1.12 ​× ​10−1 ​S ​cm−1 ​at 60 ​°C and 98% RH, which is comparable to commercially available Nafion. The mechanism of proton conduction was also well discussed. A new 3D anionic metal-organic framework material, namely, [Me 2 NH 2 ] 2 [Cd 3 (L)]·2H 2 O (1 , H 4 L ​= ​2,5′-di(3′,5′-dicarboxylphenyl)pyridine) has been synthesized under solvothermal conditions and characterized by single crystal X-ray diffraction, PXRD, thermogravimetric analysis and proton conduction investigation. Compound 1 exhibits a (4,8)-connected 3D network based on trinuclear [Cd 3 (COO) 8 ] cluster units with excellent water stability. It's worth noting that the value of proton conductivity of 1 reaches 1.12 ​× ​10−1 ​S ​cm−1 ​at 60 ​°C and 98% RH which is comparable to most of the dramatic proton conducting MOFs materials. The activation energy (E a) of 1 is 0.376 ​eV estimated by Arrhenius equation. [Display omitted] • A trinuclear Cd-based 3D (4,8)-connected anionic metal-organic framework were synthesized. • The [Me 2 NH 2 ]+ ​cations, H 2 O and host carboxylates could construct continuous proton-conducting pathways. • The MOF exhibited a remarkable proton conductivity of 1.12×10-1 ​S cm-1 ​at 60°C and 98% RH. [ABSTRACT FROM AUTHOR]