Study of Proton Conductivity of a 2D Flexible MOF and a 1D Coordination Polymer at Higher Temperature

Three robust Cd(II) coordination polymers as bifunctional luminescent probes for efficient detection of pefloxacin and Cr2O72- in water

The accurate and rapid detection of antibiotics and heavy-metal-based toxic oxo-anions in water media employing coordination polymers (CPs) as luminescent probes has attracted a lot of attention. Three new Cd(II)-based ternary CPs derived from first-presented L ligands, including [Cd(DCTP)(L)(OH)]n (1), [Cd(TBTA)(L)(OH)]n (2), and [Cd(NPHT)(L)(H2O)]n (3) (L = 2-((1H-imidazol-1-yl)methyl)-5,6-dimethyl-1H-benzo[d]imidazole, H2DCTP = 2,5-dichloroterephthalic acid, H2TBTA = tetrabromoterephthalic acid and H2NPHT = 3-nitrophthalic acid), were successfully assembled and characterized. 1 and 2 show 2D hcb layers, which can be further extended into a 3D supramolecular framework via classic hydrogen bonding interactions. 3 features a 1D double chain that ultimately spreads into a 2D network through weak hydrogen bonding interactions. With the advantages of high stability and excellent luminescent properties, the three CPs display high sensitivity, selectivity, and good anti-interference for the sensing of pefloxacin (PEF) and Cr2O72- ions (LOD values toward PEF: 3.82 × 10-7 mol L-1 for 1, 4.06 × 10-7 mol L-1 for 2, and 1.36 × 10-8 mol L-1 for 3, and toward Cr2O72- ions: 5.97 × 10-7 mol L-1 for 1, 5.87 × 10-7 mol L-1 for 2, and 8.21 × 10-8 mol L-1 for 3). These CPs are the first examples of bifunctional luminescent sensors to detect PEF and Cr2O72- in aqueous solutions. The luminescence quenching mechanisms are explored in detail.

Flattening of a Bent Sulfonated MOF Linker: Impact on Structures, Flexibility, Gas Adsorption, CO2/N2 Selectivity, and Proton Conduction

Rational design of organic building blocks provides opportunities to control and tune various physicochemical properties of metal-organic frameworks (MOFs), including gas handling, proton conduction, and structural flexibility, the latter of which is responsible for new adsorption phenomena and often superior properties compared to rigid porous materials. In this work, we report synthesis, crystal structures, gas adsorption, and proton conduction for a flexible two-dimensional cadmium-based MOF (JUK-13-SO3H-SO2) containing a new sulfonated 4,4'-oxybis(benzoate) linker with a blocking SO2 bridge. This two-dimensional (2D) MOF is compared in detail with a previously reported three-dimensional Cd-MOF (JUK-13-SO3H), based on analogous, but nonflat, SO2-free sulfonated dicarboxylate. The comprehensive structure-property relationships and the detailed comparisons with insights into the networks flexibility are supported by five guest-dependent structures determined by single-crystal X-ray diffraction (XRD), and corroborated by spectroscopy (IR, 1H NMR), powder XRD, and elemental/thermogravimetric analyses, as well as by volumetric adsorption measurements (for N2, CO2, H2O), ideal adsorbed solution theory (IAST), density-functional theory (DFT+D) quantum chemical and grand-canonical Monte Carlo (GCMC) calculations, and electrochemical impedance spectroscopy (EIS) studies. Whereas both dynamic MOFs show moderate proton conductivity values, they exhibit excellent CO2/N2 selectivity related to the capture of CO2 from flue gases (IAST coefficients for 15:85 mixtures are equal to ca. 250 at 1 bar and 298 K). The presence of terminal sulfonate groups in both MOFs, introduced using a unique prechlorosulfonation strategy, is responsible for their hydrophilicity and water-assisted proton transport ability. The dynamic nature of the MOFs results in the appearance of breathing-type adsorption isotherms that exhibit large hysteresis loops (for CO2 and H2O) attributed to strong host-guest interactions. Theoretical modeling provides information about the adsorption mechanism and supports interpretation of experimental CO2 adsorption isotherms.

Zinc(II) Carboxylate Coordination Polymers with Versatile Applications

This review considers the applications of Zn(II) carboxylate-based coordination polymers (Zn-CBCPs), such as sensors, catalysts, species with potential in infections and cancers treatment, as well as storage and drug-carrier materials. The nature of organic luminophores, especially both the rigid carboxylate and the ancillary N-donor bridging ligand, together with the alignment in Zn-CBCPs and their intermolecular interaction modulate the luminescence properties and allow the sensing of a variety of inorganic and organic pollutants. The ability of Zn(II) to act as a good Lewis acid allowed the involvement of Zn-CBCPs either in dye elimination from wastewater through photocatalysis or in pathogenic microorganism or tumor inhibition. In addition, the pores developed inside of the network provided the possibility for some species to store gaseous or liquid molecules, as well as to deliver some drugs for improved treatment.

Two-dimensional coordination polymers with high proton conductivity and ultrafast highly efficient molecular sieving constructed by the structural inductive effect

A family of unique 2D-layered Cu-based coordination polymers (abbreviated as HNNU-1α, 1β and 1γ) with different halide anions were successfully constructed using a zwitterion pyridiniumolate as the structural inductive agent (SIA). More importantly, we found that the laminates of HNNU-1α exhibit ultrafast highly-efficient molecular sieving in a water system, and HNNU-1α to 1γ display a good proton conductivity of ca. 2.2 × 10^-2, 4.9 × 10^-5, and 3.0 × 10^-4 S cm^-1 at 90 °C and 98% relative humidity (RH), respectively.

A dual-function Cd-MOF with high proton conduction and excellent fluorescence detection of pyridine

Metal-organic frameworks have great potential in the field of proton conducting materials and fluorescent probes due to their structural tunability and designability. A novel water-stable metal organic framework material [Cd₂(Hdpb)(H₂O)₃] (Cd-MOF) was synthesized based on H₅dpb (H₅dpb = 3,5-diphosphonobenzoic acid) and Cd²⁺ ions. Cd²⁺ ions are connected with phosphonates and carboxyl groups of H₅dpb to form an infinitely extended 1D chain, which is further connected by the Hdpb^4- ligand and coordinated water to form a three-dimensional network structure. There are hydrogen bond networks in the 3D structure of the Cd-MOF, which are favorable for proton transfer, achieving its maximum proton conductivity of 2.97 × 10^-3 S cm^-1 at 338 K and 98% relative humidity (RH). To realize its application in fuel cells, the Cd-MOF was introduced into the chitosan (CS) matrix, and a series of composite membranes (Cd-MOF@CS-X) with high proton conductivity were obtained. The results of AC impedance show that the proton conductivity of Cd-MOF@CS-5 reaches 3.55 × 10^-1 S cm^-1 at 358 K and 98% RH, which is comparable to the highest values reported for MOF-polymer complexes. Moreover, the Cd-MOF can be used as a selective fluorescent probe for pyridine detection, and its detection limit can reach 1.0 × 10^-6 M. A bifunctional MOF with proton conduction and pyridine recognition is reported for the first time, and has important reference value for the practical application of functional MOFs in both electrochemical and luminescence sensing.

High proton conductivity in a charge carrier-induced Ni(ii) metal–organic framework

A new tetradentate phosphonate ligand-based Ni-MOF has been synthesized and employed as an efficient proton-conducting material upon doping with sulphuric acid.

Zero area thermal expansion of honeycomb layers via double distortion relaxation in (PPh4)[Cu2(CN)3]

The zero area TE of cyanide-bridged honeycomb layers occurs by complementary structural changes in the cation and anion counterparts.

Regulating the proton conductivity of metal organic framework materials through solvent control

MOFs were used as probes through changes in the proton conductivity caused by changes in solvent molecules.

Dual-Functional Coordination Polymer with High Proton Conductivity and a Low-Detection-Limit Fluorescent Probe

A coordination polymer with dual functions of high proton conductivity and highly sensitive fluorescent sensors demonstrates a great application potential. In this work, a cadmium-based coordination polymer (denoted as CP 1) with hydrothermal stability was synthesized. The abundant coordination water, lattice water, and amino groups make an extended hydrogen-bonding pathway for efficient proton migration, which endows CP 1 with the highest proton conductivity of 2.41 × 10^-3 S·cm^-1 at 353 K and 98% RH. Especially, the proton conductivity of the chitosan (CS) hybrid membrane containing CP 1 reaches a maximum value of 2.62 × 10^-2 S·cm^-1 under 343 K and 98% RH, which increases almost 7 times higher than that of the pure CS membrane due to the host-guest collaboration. Furthermore, luminescence studies revealed that CP 1 is a high-sensitivity and good-selectivity fluorescent probe for the detection of trace amounts of l-histidine with a lowest detection limit of 1.0 × 10^-8 M.

Humidity-Sensing Properties of an 1D Antiferromagnetic Oxalate-Bridged Coordination Polymer of Iron(III) and Its Temperature-Induced Structural Flexibility

A novel one-dimensional (1D) oxalate-bridged coordination polymer of iron(III), {[NH(CH₃)(C₂H₅)₂][FeCl₂(C₂O₄)]}_n (1), exhibits remarkable humidity-sensing properties and very high proton conductivity at room temperature (2.70 × 10⁻⁴ (Ω·cm)⁻¹ at 298 K under 93% relative humidity), in addition to the independent antiferromagnetic spin chains of iron(III) ions bridged by oxalate groups (J = −7.58(9) cm⁻¹). Moreover, the time-dependent measurements show that 1 could maintain a stable proton conductivity for at least 12 h. Charge transport and magnetic properties were investigated by impedance spectroscopy and magnetization measurements, respectively. Compound 1 consists of infinite anionic zig-zag chains [FeCl₂(C₂O₄)]_nⁿ⁻ and interposed diethylmethylammonium cations (C₂H₅)₂(CH₃)NH⁺, which act as hydrogen bond donors toward carbonyl oxygen atoms. Extraordinarily, the studied coordination polymer exhibits two reversible phase transitions: from the high-temperature phase HT to the mid-temperature phase MT at T ~213 K and from the mid-temperature phase MT to the low-temperature phase LT at T ~120 K, as revealed by in situ powder and single-crystal X-ray diffraction. All three polymorphs show large linear thermal expansion coefficients.

In Situ Aliovalent Nickle Substitution and Acidic Modification of Nanowalls Promoted Proton Conductivity in InOF with 1D Helical Channel

Proton-conductive materials have attracted increasing attention because of their broad explorations in chemical sensors, water electrolysis, fuel cells, and biological systems. Especially, metal-organic frameworks (MOFs) have been demonstrated to be extremely promising candidates as proton-exchange membrane (PEM) fuel cells. Compared with other configurations, MOFs with one-dimensional (1D) channels have the characteristics of enhancing the host-guest interaction and promoting the anisotropic motion of proton carriers in restricted volume, which are beneficial for acquiring rich proton sources and forming successive hydrogen bonds to improve proton conductivity. We are endeavored to screen and find a helical three-dimensional (3D) framework InOF-1, namely, [In₂(OH)₂(BPTC)]·6H₂O (BPTC^4- = 3,3',5,5'-biphenyl tetracarboxylate), as a typical 1D-channel MOF, which is pristinely grafted with spirally distributed -OH groups on the channel surface. Accompanied by an aliovalent substitution Ni(II) for In(III), isostructural NiOF-1 ([Ni₂(BPTC)(HCOOH)₂]·3H₂O) is successfully prepared and massive formic acids are anchored at interior walls, which are interacted with adsorbed water molecules via the formation of stronger O-H···O bonds. This interaction between host-guest molecules and dynamics of lattice water has already led to a remarkable conductivity of InOF-1 (σ = 7.86 × 10^-3 S/cm at 328 K under 95% RH). The synergistic effect of the acidic-modified nanowall, contracted volume, and enhanced adsorption of water molecules in the NiOF-1 channel contributes to a high conductivity value of 3.41 × 10^-2 S/cm (at 328 K under 95% RH). Moreover, the proton conduction mechanism is further visually presented by molecular dynamic (MD) simulation. In contrast to InOF-1, aliovalent-substituted and acidic-modified NiOF-1 has a stronger host-guest interaction and more abundant hydrogen-bond networks, resulting in shorter proton migration distances and more frequent proton hopping, in agreement with the experimental results.

A Tetradentate Phosphonate Ligand-based Ni-MOF as a Support for Designing High-performance Proton-conducting Materials

Developing a robust metal-organic framework (MOF) which facilitates proton hopping along the pore channels is very demanding in the context of fabricating an efficient proton-conducting membrane for fuel cells. Herein, we report the synthesis of a novel tetradentate aromatic phosphonate ligand H₈ L (L=tetraphenylethylene tetraphosphonic acid) based Ni-MOF, whose crystal structure has been solved from single-crystal X-ray diffraction. Ni-MOF [Ni₂ (H₄ L)(H₂ O)₉ (C₂ H₇ SO)(C₂ H₇ NCO)] displays a monoclinic crystal structure with a space group of P 2₁ /c, a=11.887 Å, b=34.148 Å, c=11.131 Å, α=γ=90°, β=103.374°, where a nickel-hexahydrate moiety located inside the void space of the framework through several H-bonding interactions. Upon treatment of the Ni-MOF in different pH media as well as solvents, the framework remained unaltered, suggesting the presence of strong H-bonding interactions in the framework. High framework stability of Ni-MOF bearing H-bonding interactions motivated us to explore this metal-organic framework material as proton-conducting medium after external proton doping. Due to the presence of a large number of H-bonding interactions and the presence of water molecules in the framework we have carried out the doping of organic p-toluenesulfonic acid (PTSA) and inorganic sulphuric acid (SA) in this Ni-MOF and observed high proton conductivity of 5.28×10^-2  S cm^-1 at 90 °C and 98% relative humidity for the SA-doped material. Enhancement of proton conductivity by proton doping under humid conditions suggested a very promising feature of this Ni-MOF.

Two 6/10-connected Cu12S6 cluster-based organic frameworks: crystal structure and proton conduction

Nowadays, although the exploration of proton conductive materials has ranged from traditional sulfonated polymers to novel crystalline solid materials such as MOFs, COFs, and HOFs, research on crystalline cluster-based organic framework materials is very limited. Here, a pair of homologues Cu(i)-based organic framework containing a Cu12S6 cluster, [Cu12(MES)6(H2O)3]n (1) and {[Cu12(MPS)6(H2O)4]·6H2O}n (2) (H2MES = 2-mercaptoethanesulfonate acid and H2MPS = 2-mercaptoethanesulfonate acid), were hydrothermally synthesized under the same conditions and fully investigated for their proton conduction. Their structures were characterized by means of single-crystal X-ray diffraction, elemental analysis, thermogravimetric analyses, and PXRD measurements. The two MOFs show significant structural differences in the topological fashions. MOF 1 has a three-dimensional network and can be simplified into two topology types: a 10-connected gpu structure with a Schläfli symbol (312·426·57) and a 3,12-connected new topology with a point symbol {3·42}2{310·418·519·614·74·9}. MOF 2 also has a three-dimensional framework and topology as a 6-connected pcu primitive cubic network with a Schläfli symbol {412·63}. The two MOFs show different proton conduction parameters, but both indicate temperature-dependent proton conductive features. Intriguingly, the two MOFs exhibit high water stability and their proton conductivities are 3.63 × 10-5 and 2.75 × 10-5 S cm-1 under 333 K and 98% RH, respectively. The suggested mechanism for the synthesis for 1 and 2, and their proton conductivity performance comparison has been discussed in detail. In addition, Hirshfeld surface and fingerprint analysis on the two MOFs were computed to compare contacts between the molecules, which is essential for analyzing the relationships between their hydrogen bonds and proton conductivity properties.

Synthesis of a palladium based MOF via an effective post-synthetic modification approach and its catalytic activity towards Heck type coupling reactions

The complete exchange of metal nodes in a MOF with the Pd(ii) ions was done without losing the structural integrity. The new MOF turned out to be an excellent catalyst for the C–C bond formation via un-reacted cleavage C–N bond of arylhydrazines.

Highly selective sensing of Fe3+/Hg2+ and proton conduction using two fluorescent Zn(ii) coordination polymers

A pair of homologues, [Zn(Hssa)(1,4-bib)·H2O]n (1) and [Zn3(ssa)2(1,4-bib)3·4H2O]n (2), were successfully assembled using the same metals and ligands [H3ssa = 5-sulfosalicylic acid; 1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene] under solvothermal conditions. Polymer 1 is a two-dimensional (2D) sql network and polymer 2 is a three-dimensional (3D) framework. Polymer 2 can be simplified into two topology types: bct and tfc. The two polymers show significant differences in the fluorescence sensing of metal ions and proton conductivity. Their applications in detecting metal ions and proton conductivity were explored. Polymer 1 shows high sensitivity and selectivity for Fe3+, while polymer 2 can detect Hg2+ ions. The limit of detection was 1.66 μM with Fe3+ for 1 and 0.23 μM with Hg2+ for 2 in water. In addition, both 1 and 2 exhibit high water stability and proton conductivity. At 60 °C and 95% relative humidity, their conductivities were 3.45 × 10-5 and 6.26 × 10-6 S cm-1, respectively. A detailed analysis of the Hirshfeld surface and fingerprints was carried out for 1 and 2 to compare the interactions between the molecules, which is essential for analysing the relationship between their structures and material properties.

Proton-Conductive Coordination Polymers Based on Diphenylsulfone-3,3'-disulfo-4,4'-dicarboxylate with Well-Defined Hydrogen Bonding Networks

The diphenylsulfone-3,3'-disulfo-4,4'-dicarboxylic acid (H₄-DPSDSDC) ligand and its coordination polymers, [K₂Zn(C₁₄H₆S₃O₁₂)(H₂O)₄]_n (1) and {[Cu₃(μ₃-OH)₂(C₁₄H₆S₃O₁₂)(H₂O)₃(DMF)]·3(H₂O)}_n (2) (C₁₄H₆S₃O₁₂ = diphenylsulfone-3,3'-disulfo-4,4'-dicarboxylate), were synthesized. The Zn(H₂O)₄ units in 1 are connected by DPSDSDC^4- ligands to generate a one-dimensional (1D) chain, which is bridged by K-O bonds associated with bridging water molecules and sulfonate groups to yield a two-dimensional (2D) layer. In 2, the 1D hydroxyl-bridging Cu(II) chains are connected by DPSDSDC^4- ligands to give a 2D layer. The 2D layers in 1 and 2 are further connected by interlayered hydrogen bonds to give three-dimensional (3D) frameworks. Compounds 1 and 2 have good conductivities of 1.57 × 10^-4 and 5.32 × 10^-5 S cm^-1, respectively. Continuous well-defined hydrogen bonding networks associated with water molecules, sulfonate groups, and carboxylate groups were observed in compounds 1 and 2. Such hydrogen bonding networks provide hydrophilic domains and effective transfer pathways for protons. Here, we present elegant examples of a precise determination of the pathways for proton transport.

Metal Organic Frameworks Modified Proton Exchange Membranes for Fuel Cells

Proton exchange membrane fuel cells (PEMFCs) have received considerable interest due to their low operating temperature and high energy conversion rate. However, their practical implement suffers from significant performance challenge. In particular, proton exchange membrane (PEM) as the core component of PEMFCs, have shown a strong correlation between its properties (e.g., proton conductivity, dimensional stability) and the performance of fuel cells. Metal-organic frameworks (MOFs) as porous inorganic-organic hybrid materials have attracted extensive attention in gas storage, gas separation and reaction catalysis. Recently, the MOFs-modified PEMs have shown outstanding performance, which have great merit in commercial application. This manuscript presents an overview of the recent progress in the modification of PEMs with MOFs, with a special focus on the modification mechanism of MOFs on the properties of composite membranes. The characteristics of different types of MOFs in modified application were summarized.

Ni(II)-Based Metallosupramolecular Polymer with Carboxylic Acid Groups: A Stable Platform for Smooth Imidazole Loading and the Anhydrous Proton Channel Formation

The Ni(II)-based metallosupramolecular polymer with carboxylic acid groups (polyNi) was synthesized via a 1:1 complexation of Ni(II) salt with (4,4'-(9,9-dihexyl-9H-fluorene-2,7-diyl)bis(pyridine-2,6-dicarboxylic acid) for the first time. The divalent state of Ni(II) in the polymer was confirmed by the X-ray absorption fine structure analysis. Smooth loading of imidazole molecules into polyNi proceeded with the help of the carboxylic acid groups to form the imidazole-loaded polyNi (polyNi-Im). Thermogravimetric analysis of polyNi-Im revealed that approximately three imidazole molecules were incorporated per repeating unit of polyNi. The Fourier transform infrared spectrum of polyNi-Im showed a new peak at 3219 cm-1, which shows an ∼73 cm-1 enhancement to -N-H of pristine imidazole. The peak suggests the formation of an imidazolium cation in the polymer. Powder X-ray diffraction indicated no degradation of the polymer structure during the imidazole loading because the diffraction pattern of polyNi-Im was almost the same as that of polyNi except for the presence of peaks corresponding to the imidazole molecules. Interestingly, the scanning electron microscopy measurement showed a large morphological change to uniform spherical particles by loading imidazole to the polymer. PolyNi-Im exhibited good proton conductivity (1.05 × 10-2 mS/cm) at a high temperature (120 °C), which is around 7 orders of magnitude higher than that of pristine polyNi because of the proton conduction pathway formation along the polymer chains by the incorporated imidazole molecules.

A dual-functional metal phosphate for high proton conduction and selective luminescence turn-on sensing of Co2+ ions

The {[Zn(H₂PIPZ)](H₂O)}_n (compound 1) detects Co²⁺ ions with turn on fluorescent and proton conductivity of composite membrane 1@PVA10 is ten times higher than compound 1 at 98% RH and 353 K.

High protonic conduction in two metal–organic frameworks containing high-density carboxylic groups

The proton conductivities of two stable 2D MOFs are much higher than those of most non-porous PC-MOFs and comparable to those of porous PC-MOFs.

From an organic ligand to a metal–organic coordination polymer, and to a metal–organic coordination polymer–cocrystal composite: a continuous promotion of the proton conductivity of crystalline materials

A new strategy was proposed to increase proton conductivities in metal–organic coordination polymers (MOCPs) commencing from organic ligands, i.e. coordination inducement and MOCP–cocrystal composite formation.

A copper(ii)-coordination polymer based on a sulfonic–carboxylic ligand exhibits high water-facilitated proton conductivity

The coordination polymer {[Cu₂(sba)₂(bpg)₂(H₂O)₃]·5H₂O}_n encapsulates arrays of water molecules H-bonded to the framework displaying a high conductivity value of 0.94 × 10⁻² S cm⁻¹ with an activation energy of 0.64 eV.

Water-mediated proton conduction in Ni(ii) and Co(ii) benzenetriphosphonates

Two novel transition metal compounds, [Ni(4,4′-bipyH)₂(H₂O)₄]·2(H₄bmt)·9H₂O (1) and [Co(4,4′-bipy)(H₂O)₄][Co(4,4′-bipyH)₂(H₂O)₄]·2(H₃bmt)·6H₂O (2), have been synthesized.

A water stable layered Tb(iii) polycarboxylate with high proton conductivity over 10−2 S cm−1 in a wide temperature range

An unprecedented Tb(iii) polycarboxylate, {[Tb₄(TTHA)₂(H₂O)₄]·7H₂O}_n (1), has been synthesized.

High proton conductivity in a nickel(ii) complex and its hybrid membrane

A novel 2D nickel(ii) complex (1) has been successfully synthesized using a 2,2′-bipyridyl, polycarboxylsulfonate ligand H₄SBTC and Ni²⁺ ions. Owing to the presence of abundant water molecules, hydrogen bond networks and other protons, 1 and its hybrid membranes demonstrate high proton conductivity.

High proton conduction behavior in 12-connected 3D porous lanthanide–organic frameworks and their polymer composites

Two novel 12-connected 3D porous lanthanide–organic frameworks have been synthesized by the reaction of bipyridine-carboxylate ligand bpydbH₂ and lanthanide metal ions. Both of them show a high proton conduction behavior as well as their composite membranes.

Water mediated proton conductance in a hydrogen-bonded Ni(ii)-bipyridine-glycoluril chloride self-assembled framework

Proton conducting properties have been investigated in a new Ni(ii)-based hydrogen-bonded porous framework synthesized using bipyridine-glycoluril (BPG) tecton.

Iron(iii) identification and proton conduction of a luminescent cadmium–organic framework

A luminescent metal–organic framework, [Cd(HDMPhIDC)(H₂O)]_n (1), has been successfully synthesized and structurally characterized. MOF 1 exhibits good recognition performance for Fe³⁺ ions. The recognition mechanism of Fe³⁺ was explored by UV-Vis and PXRD determinations. 1 was found to have a high proton conductivity value of 1.30 × 10⁻⁴ S cm⁻¹ at 100 °C and 98% RH.

Synthesis, crystal structures, and magnetic properties of six transition metal phosphonates

Six new complexes have been quantificationally investigated for magnetic properties. There are abundant water molecules existing in the complexes with different aggregation modes.

3D isomorphous lanthanide coordination polymers displaying magnetic refrigeration, slow magnetic relaxation and tunable proton conduction

Four lanthanide 3D coordination frameworks with 1D hydrophilic channels along the crystallographic c direction have been investigated for their proton conduction and magnetic properties.

Highly tuneable proton-conducting coordination polymers derived from a sulfonate-based ligand

Three highly proton-conducting coordination compounds have been synthesized via the HCl steaming-assisted conversion approach by using multiple functional groups including the sulfonate group and the Cl⁻ or HPO₄²⁻ group.