In this study, we used the facile solvent evaporation method to achieve the inorganic–organic hybrid crystals of [triethylpropylammonium][PbI3], which have been characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and differential scanning calorimetry as well as single-crystal X-ray structure analysis. The hybrid solid crystallizes in the monoclinic space group P21/c at room temperature and is composed of one-dimensional [PbI3]∞ chains, where the neighboring PbI6 coordination octahedra connect together via the face-sharing mode and the organic cations fall in the spaces between [PbI3]∞ chains. The hybrid exhibits a dielectric phase transition with a critical temperature of ca. 432 K, dielectric relaxation at frequencies below 107 Hz, and single-ion conducting behavior, the conductivity of which increases rapidly from 9.43 × 10–10 S cm–1 at 383 K to 4.47 × 10–5 S cm–1 at 473 K. The variable-temperature single-crystal and powder X-ray diffraction analyses revealed that the dielectric phase transition is related to the disorder-to-order transformation of cations in the lattice. The electric modulus and impedance spectral analyses further disclosed that the dielectric relaxation arises from the ionic displacement polarization and molecular dipole orientation of cations. The single-ion conductance is due to the migration of cations that fall in the spaces of rigid inorganic [PbI3]∞ chains. The phase transition gives rise to this hybrid showing switchable ion-conducting nature around the critical temperature of the phase transition. Besides the fascinating functionalities mentioned above, the hybrid also exhibits a thermochromic luminescence feature originating from the electron transition between the valence and conduction bands of the inorganic [PbI3]∞ chain.

Kaolinite, with a chemical formula of Al2Si2O5(OH)4, is an abundant and broadly available layered clay mineral. The aluminosilicate monolayer of kaolinite is composed of [SiO]6 macrorings on one side and gibbsite aluminol groups [Al(OH)3] on the other side. In this study, ethylene glycol (EG) molecules were covalently grafted to the inner surfaces of kaolinite via etherification between EG hydroxyl and gibbsite aluminol groups to obtain a hybrid material, covalently grafted kaolinite (denoted as K-EG-cg). Commonly, the preparation of K-EG-cg via the conventional heating and stirring method takes longer time (ca. 16 hours); however, only ca. 6 hours are required to achieve K-EG-cg using the solvothermal reaction; moreover, the intercalation efficiency or ratio of the product obtained via the solvothermal reaction is comparable to that obtained using the conventionally heating and stirring method. Infrared spectroscopy, thermogravimetric (TG) analysis, and powder X-ray diffraction were performed; the measurements clearly demonstrate that K-EG-cg is a covalently grafted product and not the result of the physical intercalation of kaolinite with EG (abbr. K-EG). Moreover, the hybrid material K-EG-cg showed much higher deintercalation temperature as compared to K-EG. The dielectrics of K-EG-cg was investigated, indicating that this hybrid material showed intrinsic ferroelectric nature, with the spontaneous polarization PS ≈ 0.018 μC cm−2, remanent polarization Pr ≈ 0.015 μC cm−2, and coercive field EC ≈ 1.045 kV cm−1 at room temperature. This study provides a fresh impetus to achieve kaolinite-based hybrid functional materials via the covalent grafting approach, which can overcome the disadvantage of thermal instability of the intercalated kaolinite.

A two-dimensional coordination polymer, [Mn3(HEBTC)2(DMSO)6] (1), has been achieved by a solvothermal reaction of Mn2+ with 1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylic acid (H4EBTC). The layer of a coordination polymer is composed of trinuclear Mn2+ clusters linked by HEBTC3− ligands to form a (3,6)-connected topological net. CP 1 with paramagnetic Mn2+ ions shows dual emissions centered at 397 and 468 nm in the solid state under ambient conditions with respectable quantum yields of 15.3% (397 nm) and 12.3% (468 nm). The dual emissions arise from n ← π* transition in HEBTC3− and MLCT between HEBTC3− and Mn2+ centers.

Proton conducting materials have important technological applications as key components in electrochemical devices, including fuel cells, electrochemical sensors, electrochemical reactors and electrochromic displays. And the exploration of novel proton conducting materials is significant for the development of efficient electrochemical devices. In this study, we have investigated the proton conductance of an open-framework manganese(II) phosphite, (NH4)0.59(H3O)1.41Mn5(HPO3)6 (1). The open-framework manganese(II) phosphate shows superior water-stability and excellent thermal stability. There was intrinsic water-assisted proton conductivity with σ = 3.94 × 10−4 S cm−1 at 328 K and 98% RH. Furthermore, composite membranes have further been fabricated using polyvinylidene fluoride (PVDF) and 1, labeled as 1@PVDF-X, where the symbol X represents the mass percentage of 1 (as X%) in the composite membrane and X = 10–55%. The composite membranes display good mechanical performance and durability for practical applications, and the proton conductivity of 1@PVDF-55 reaches 3.32 × 10−5 S cm−1 in deionized water at 336 K.

The solid state electrolytes show a wide range of practical applications in a variety of all-solid-state electrochemical devices, and it is highly in demand to explore new types of solid state electrolyte materials. In this study, we have designed and prepared a fluorite-type coordination compound, [Mn(en)3]I2, which has been characterized by microanalysis for C, H and N elements, infrared spectrum in the wavenumber range of 4000–400 cm−1, thermogravimetric analysis and differential scanning calorimetry. The single crystal X-ray diffraction revealed that the bigger size [Mn(en)3]2+ cations build three-dimensional network in the crystal of [Mn(en)3]I2 and the smaller size iodide ions occupy the tetrahedral or octahedral cavities surrounded by the [Mn(en)3]2+ cations, featuring as the fluorite-type compound. The impedance spectra were investigated to reveal the ionic conductivity σ = 3.45 × 10−11 S cm−1 at 303 K, while σ = 1.37 × 10−6 S cm−1 at 423 K, sharply increasing by five orders of magnitude regarding to that at 303 K. The electric modulus analysis further confirmed the conductance contributed from the migration of iodide ions. This study opens a way to design and achieve new coordination compound-based ion conductors.

•New organic-inorganic hybrid crystal material was synthesized at room temperature.•Hydrogen bonds directed the final 3D architecture assembly.•The Hirshfeld surface analysis reveals the percentage of intermolecular contacts in lattice.•This material shows novel XPS spectroscopy and EPR silence.The synthesis and physico-chemical characterization of an organic-inorganic hybrid material, (N, N'-bi-n-butyl-4,4′-bipyridinium tetrabromocuprate, has been reported. This hybrid has been characterized using IR, thermogravimetric and single-crystal X-ray diffraction analyses. In the title salt, (C18H26N2)[CuBr4], the CuBr42 − ion shows distorted tetrahedral geometry. The tetrabromocuprate and N, N'-bi-n-butyl-4,4′-bipyridiniums are held together via non-classical CH ⋯ Br hydrogen bond to form a 3-D hybrid structure. The percentages of hydrogen bonding interactions are analyzed by fingerprint plots of Hirshfeld surface. The XPS spectrum exhibits the signals of coexistence of CuI and CuII ions. However, the hybrid shows EPR silent behavior at room temperature and variable-temperature magnetic susceptibility displays an isolation of CuII feature with C = 0.46 emu K mol− 1 and θ approximate to − 0.06 K in 2– K as well. Such a novel nature is further analyzed and discussed.A new organic-inorganic hybrid crystal material (C18H26N2)[CuBr4] has been synthesized. This hybrid shows novel XPS spectroscopy and EPR silent behavior at room temperature. The variable-temperature magnetic susceptibility displays an isolation of CuII feature.Download high-res image (68KB)Download full-size image

In this study, a new two-dimensional Pb2+-based coordination polymer (CP), [Pb2(EBTC)(DMSO)3] (1), where H4EBTC is 1,1′-ethynebenzene 3,3′,5,5′-tetracarboxylic acid, was synthesized under solvothermal conditions. Structural analysis reveals that 1 crystallizes in the monoclinic space group C2/m, where two crystallographically different Pb2+ ions show a coordination geometry of bicapped trigonal prisms that are connected to a double-chain by the EBTC4− ligands through carboxylate groups along the b-axis direction, and where successive double chains are held together to form a 2D layer via the Pb1 and Pb2 bicapped trigonal prisms sharing one edge or a triangle face along the c-axis direction. Interestingly, CP 1 emitted intense and long-lived greenish phosphorescence in the solid state at ambient conditions, with a quantum yield of 1.5% and a phosphorescence lifetime of 4.17 ms, and the emission mainly arose from the electron transition within the π-type orbitals of the EBTC4− ligand. The emission bands assignment and photophysical process were further discussed according to the calculation of both the electronic band structures and density of states. This study gives a fresh impetus to achieve coordination polymer-based long-lived phosphorescence materials under ambient conditions.

A new heteroleptic nickel-bis-1,2-dithiolene ion-pair complex, (4-ClBz-1-APy)[Ni(dmit)(mnt)] (1) (where 4-ClBz-1-APy+ = p-chloro-benzyliden-1-aminopyridinium; dmit2− = 2-thioxo-1, 3-dithiole-4, 5-dithiolate; mnt2− = maleonitriledithiolate) was synthesized and characterized structurally. The IR spectra, thermal analysis, magnetic and near-IR absorption properties have been investigated for 1. Complex 1 crystallized in monoclinic system with space group P21. The anions and cations form the mixed stacked columns separated by the cation columns. The anion stacks are irregular, in which two neighboring heteroleptic [Ni(dmit)(mnt)]− anions are separated by one 4-ClBz-1-APy+ cation. The neighboring anions are connected via lateral-to-lateral S…S contacts of dmit2− ligands and short H…N, H…S and C…S contacts are observed between the cations and the anions. Magnetic susceptibility measurement shows that the magnetic data follows the S = 1/2 Heisenberg alternating linear-chain model in the temperature range 40–300 K and Curie-Weiss law below 40 K for 1. Salts 1 exhibits a intense near-IR absorption in the region of 900–1400 nm, and this near-IR absorption feature makes it to be a promising optical material.A new heteroleptic nickel-bis-1,2-dithiolene ion-pair complex was synthesized and characterized structurally. Magnetic susceptibility and UV–Vis-NIR spectral measurements show that the magnetic behavior follows the S = 1/2 Heisenberg alternating linear-chain model in high temperature range and Curie-Weiss law in low temperature range for 1, and a intense near-IR absorption for 1 and [BzQl][Ni(dmit)(mnt)].Download high-res image (89KB)Download full-size image

•A bimetallic metal-organic framework shows a pillar-layered structure.•The MOF displays novel dielectric anomaly and relaxation behaviors.•The dielectric anomaly arises from the stacking structure transformation of guests.•The dielectric relaxation is related to the dipole dynamics of guests.A bimetallic metal–organic framework (MOF) with the formula [Zn3btc2{Cr3O(isonic)6(H2O)2(OH)}]·(DMF)15.5(H2O)8 (H3btc=1,3,5-benzenetricarboxylic acid; isonic=isonicotinicate) shows a pillar-layered structure. The monolayer consists of hexagon-like rings formed by the [Zn(isonic)2(btc)2] tetrahedral and the consecutive monolayers are pillared by trigonal–prismatic clusters of [Cr3O(isonic)6(H2O)2(OH)]through the remaining binding sites of the Zn2+ ions. DMF and water molecules are confined in the cages and channels. TGA indicates that the lattice DMF and water molecules begin to be released at temperatures above 363 K. Dielectric measurements were carried out in the range of 173–363 K and 1–107 Hz for three successive thermal cycles. The dielectric spectroscopy obtained in the first thermal cycle was different from that observed in the next two thermal cycles, while the dielectric spectra in the last two thermal cycles were almost identical. The dielectric nature of this MOF is discussed in detail for each thermal cycle. Since MOFs are unique host–guest systems in which the structure of the host framework is designable and the guests are exchangeable, it is no doubt those MOFs are materials with a variety of dielectric natures. This study gives a fresh impetus to achieve MOFs–based dielectric materials.The bimetallic MOF [Zn3btc2{Cr3O(isonic)6(H2O)2(OH)}]·(DMF)15.5(H2O)8 1, shows a pillar-layered open-framework structure. The dielectric spectra of 1 are almost identical in the last two thermal cycles, whereas significantly different from that observed in the first thermal cycle. The novel dielectric anomaly associated with a stacked structure transformation of the disordered guests.Download high-res image (247KB)Download full-size image

A Zn-based metal-organic framework (MOF)/porous coordination polymer (PCP), (EMIM)[Zn(SIP)] (1) (SIP3– = 5-sulfoisophthalate, EMIM+ = 1-ethyl-3-methylimidazolium), was synthesized using the ionothermal reaction. The Zn2+ ion adopts distorted square pyramid coordination geometry with five oxygen atoms from three carboxylates and one sulfo group. One of two carboxylates in SIP3– serves as a μ2-bridge ligand to link two Zn2+ ions and form the dinuclear SBU, and such SBUs are connected by SIP3– ligands to build the three-dimensional framework with rutile (rtl) topology. The cations from the ion-liquid fill the channels. This MOF/PCP shows two-step dielectric anomalies together with two-step dielectric relaxations; the variable-temperature single-crystal structure analyses disclosed the dielectric anomaly occurring at ca. 280 K is caused by an isostructural phase transition. Another dielectric anomaly is related to the dynamic disorder of the cations in the channels. Electric modulus, conductance, and variable-temperature solid-state 13C CP/MAS NMR spectra analyses revealed that two-step dielectric relaxations result from the dynamic motion of the cations as well as the direct-current conduction and electrode effect, respectively.

The organic–inorganic hybrid crystal Ni(en)3Ag2I4 (where en represents 1,2-ethylenediamine) crystallizes in hexagonal space group P63, in which the AgI43– tetrahedra connect into a diamondlike inorganic framework via sharing of the vertex and the Ni(en)32+ octahedra fill in the pores of the framework. UV–vis–near-IR (NIR) spectroscopy disclosed that this hybrid shows intense NIR absorbance centered at ca. 870 nm, and the variable-temperature conductivity measurement revealed that the hybrid is a semiconductor with Ea = 0.46 eV. The electronic band structure of Ni(en)3Ag2I4 was calculated using the density functional theory method, indicating that the NIR absorbance arises from d-d transition within the Ni2+ cation of Ni(en)32+. The homogeneous, compact, and transparent crystalline film of Ni(en)3Ag2I4 was fabricated via a secondary seed growth strategy, which has promising application in NIR devices.

The inorganic–organic hybrid metal hydrogenophosphate with a formula of (C2H10N2)[Mn2(HPO4)3](H2O) (1) shows layered crystal structure. The inorganic anion layer is built from Mn3O13 cluster units, and the interlayer spaces are filled by the charge-compensated ethylenediammonium dications together with the lattice water molecules. The thermogravimetry, variable-temperature powder X-ray diffraction, and the proton conductance under anhydrous and moisture environments were investigated for 1, disclosing that 1 shows high thermal stability and high proton transport nature, and the proton conductivity reaches to 1.64 × 10–3 S·cm–1 under 99%RH even at 293 K. The high proton conductivity is related to the formation of denser H-bond networks in the lattice.

A clathrate NH4Br@HKUST-1 has been prepared by means of soaking the metal–organic-framework, HKUST-1, in ammonium bromide saturated ethanol solution at ambient temperature. Both NH4Br@HKUST-1 and HKUST-1 show the same framework structure. The formula of the clathrate is approximately expressed as Cu3(BTC)2(NH4Br)1.15. The thermal stability of the metal–organic framework is not affected by incorporating ammonium bromide into its pores. The impedance spectra measurements were performed for both NH4Br@HKUST-1 and HKUST-1 in anhydrous and selected relative humidity environments, disclosing that the conductivity of NH4Br@HKUST-1 is enhanced by three/four orders of magnitude under the same conditions with respect to HKUST-1. This study provided an efficient strategy to achieve new high conductivity proton transport materials.

Films of Prussian blue analogue (PBA) Co3[Co(CN)6]2 were fabricated on porous α-alumina, ITO glass, silicon wafer and non-woven fabric substrates via a facile self-assembly method, and were characterized using infrared spectroscopy, X-ray powder diffraction and scanning electron microscope techniques. The films composed of truncated cube-shaped PBA particles are highly oriented with a preferred (100) plane on the glossy and smooth surfaces of ITO glass and silicon wafer, but crystallographically isotropic on the rough surface of porous α-alumina and non-woven fabric substrates. Compact films were achieved on porous α-alumina and surface-functionalized ITO glass. Reversible solvatochromism/vapochromism was discovered and investigated for the powdered and thin-film PBA samples. Such peculiar solvatochromism/vapochromism is related to the process of the adsorbed solvent molecules replacing the coordinated water molecules in octahedral Co2+–(N)4(H2O)2. The change of the Co2+ ion’s coordination atmosphere leads to the variation of crystal field strength, as a result, the d–d transitions within the Co2+ ions are altered to give rise to a color change.

A highly thermally stable CP/MOF, comprised of Mg2+ and H2EBTC2− with the formula of [Mg(H2EBTC)(DMF)2], emits dual band luminescence centered at 376 and 555 nm. The former is assigned to the fluorescence of H2EBTC2− and the latter with 1.63 μs decay lifetime and large Stokes shifts corresponds to the phosphorescence of H2EBTC2−. To the best of our knowledge, this is the first time the ligand-based phosphorescence in a CP/MOF without any heavy atom at room temperature has been observed.

An iodoplumbate-based hybrid, [C7-Apy][PbI3] (1), where C7-Apy+ = 1-heptyl-4-aminopyridinium, was prepared using a simple solution process. Three sequential phase transitions occur in the range of 402–443 K. In both the lowest and highest temperature phases, hybrid crystal 1 is composed of discrete [Pb2I6]∞ twin chains surrounded by C7-Apy+ cations. The connectivity between PbI6 octahedra within a [Pb2I6]∞ twin chain and the arrangement of cations are quite difference between the lowest and highest temperature phases. Hybrid crystal 1 shows switchable ion conductivity due to the structural phase transition and white light emission attributed to the broad band semiconductor emission of the twin chain. The former functionality has potential application in ion conductor devices; the single-phase white light emitter is a useful material in low-cost, easily-made, high-efficiency white light-emitting diodes.

A coordination polymer (CP) of Mg2+ with 1,3,5-benzenetricarboxylate (BTC3−) was synthesized using a solvothermal method. The Mg-CP, with a formula of Mg3(BTC)(HCOO)3(DMF)3, crystallizes in the trigonal space group P, with cell parameters of a = b = 13.972(5) Å, c = 8.090(5) Å and V = 1367.6(11) Å3, and shows a lamella structure built from planar rosette-type hexanuclear architectures. The Mg-CP emits intense blue fluorescence arising from π* → π transition of intra-ligand of BTC3− with 21.69% quantum yield, yet it exhibits poor stability to water. The composites of Mg-CP with hydrophobic polyvinylidene fluoride (PVDF) were sequentially prepared by mechanically mixed, tableted and annealed processes, which showed good compatibility between Mg-CP and PVDF, high hydrostability, and intense blue emission. This study suggests a simple but efficient method to solve the drawbacks of some functional CPs unstable to water and to promote them as practical applications in the field of functional materials.

A new salt [H2DABCO][Pt(mnt)2]2 (1) (mnt2-=maleonitriledithiolate and H2DABCO2+ is diprotonated 1,4-diazabicyclo[2.2.2]octane) has been synthesized; its crystal structure, magnetic and near-IR absorption properties have been investigated. Two different [Pt(mnt)2]- anions form the strong π-dimers, labeled as Pt(1)-dimer and Pt(2)-dimer, with quite shorter Pt…Pt and S…S distances and molecular plane-to-plane distance (<3.5 Å) within a dimer. The [Pt(mnt)2]22- π-dimers are connected through the cations in the strong H-bond manner to form three-dimensional H-bond supramolecular crystal. The salt shows weak paramagnetism in 1.99–300 K and this is due to the existence of strong antiferromagnetic coupling within a π-dimer. In addition, a small thermal hysteresis loop is observed at ca. 120 K, indicating that a phase transition probably occurs that is further confirmed by variable-temperature IR spectra. Another fascinating functionality of 1 is the intense near-IR absorption in the region of 750–2500 nm, and this near-IR absorption feature makes it to be a promising optical material.A H-bond supramolecular crystal of [H2DABCO][Pt(mnt)2]2 shows a magnetic phase transition at ca. 120 K with sizable thermal hysteresis loop and intense near-IR absorption in the region of 750–2500 nm.

•A quasi-amorphous inorganic-organic hybrid solid (PDDA/PMA) has been synthesized.•Water molecules were trapped in the PDDA/PMA network.•The PDDA/PMA exhibits multistep dielectric anomalies and dielectric relaxations.•The mechanism of the dielectric anomalies are explored.A quasi-amorphous inorganic-organic hybrid solid, which is comprised of poly(diallyldimethylammonium) polyelectrolyte cations with phosphomolybdates and denoted as PDDA/PMA, was prepared and characterized using elemental analysis, powder x-ray diffraction, IR spectrum, thermal and energy dispersive X-ray analyses. The PDDA/PMA exhibits multistep dielectric anomalies and dielectric relaxations. The dielectric anomaly around 353 K arises partially from the water trapped in the PDDA/PMA network releasing. The PDDA/PMA was further dried under vacuum at 373 K to give water-free sample PDDA/PMA-1. With water being removed, the broad anomaly peak around 353 K in the ε′-T plot of PDDA/PMA changes into a platform in that of PDDA/PMA-1, indicating that the dielectric anomalies result from not only losing water but also the network disorder in PDDA/PMA-1. In addition, the platform strongly depends on the AC frequency in PDDA/PMA-1; the electric modulus and ion conductance analyses demonstrated that the dielectric relaxations at elevated temperature are related to the PMA ions displacing motion.A amorphous inorganic-organic hybrid solid, comprised of poly(diallyldimethylammonium) polyelectrolyte cations with phosphomolybdates, shows novel dielectric anomaly and relaxation, which are related to the losing water trapped in the polyelectrolyte network and phosphomolybdates displacement.

•Inorganic–organic hybrids contain {Ag2I42 −} open-framework.•Hybrids exhibit dielectric anomaly and relaxation.•Hybrid is a low-κ material.In this paper, the dielectric spectroscopy was studied for two isomorphic hybrids, Zn(en)3Ag2I4 and Ni(en)3Ag2I4. Two hybrids show temperature-independent dielectric permittivity and loss with εʹ ≈ 6.7 and εʺ ≈ 0.03 at temperatures below 200 K for Zn(en)3Ag2I4 versus εʹ ≈ 1.24 and εʺ ≈ 0.01 at temperatures below 250 K for Ni(en)3Ag2I4, as well as a dielectric anomaly and thermally assisted dielectric relaxation at elevated temperature. The anomaly peak temperature is ca. 300 K for Zn(en)3Ag2I4 versus ca. 380 K for Ni(en)3Ag2I4 in εʹ-T plots. Additionally, the εʹ value is < 2.6 at temperature below 360 K for Ni(en)3Ag2I4, which is a low-κ material. The dielectric property distinction between two hybrids results from their different structural rigidity.Inorganic–organic hybrids, Zn(en)3Ag2I4 and Ni(en)3Ag2I4, with three-dimensional {Ag2I42 −} open-framework show low-κ in low temperature regime, while dielectric anomaly and relaxation at elevated temperature.

Multifunctional materials that display different physical properties in a single phase can be utilized in multifunctional devices that are capable of performing more than one task simultaneously. In this study, we synthesized a novel multiple phase transition charge transfer salt [4′-tBu-BzPy][Ni(mnt)2] (4′-tBu-BzPy+ = 4′-tert-butylbenzyl-pyridinium, mnt2− = maleonitriledithiolate) by incorporating a tert-butyl group to control the rotational dynamics in the crystal and to pre-program the amphidynamic [Ni(mnt)2]− magnetic lattice. This salt experienced a two-step structural transformation to give three separate high, immediate and low temperature phases. Interestingly, two structural transformations were coupled to both hysteretic magnetic phase transitions at 187/192 K and 94/96 K, and to dielectric anomalies. These results will assist the design and preparation of novel multiple phase-transition materials harboring technologically important magnetic and dielectric properties.

The integrated, highly crystalline and water stable Prussian blue analogue films were successfully fabricated on the porous α-Al2O3, the conducting ITO and the flexible non-woven fabric substrates, respectively, using the self-assembly approach. The proton conduction was investigated for both powdered pellets and the film on the porous α-Al2O3 substrate. This study promotes the practical applications of MOF-based proton conductors in various devices.

The intercalated kaolinite with potassium acetate (K-KAc), with ca. 91.9% intercalation ratio, was prepared. Thermogravimetric and variable-temperature X-ray powder diffraction analyses disclosed that a small amount of water is easily absorbed into the interlayer space of the K-KAc. The previously reported phase with the 14.2 Å interlayer distance is actually the hydrous K-KAc, which has an approximate formula of Al2Si2O5(OH)4·0.5KAc·0.25H2O. The crystal structures of hydrous and anhydrous phases of K-KAc were simulated in the density functional theory framework, demonstrating that the interactions between the K+ and acetate ions and the inner surface of kaolinite are significantly strengthened in the anhydrous phase with regard to the hydrous phase. The ionic conductivity of K-KAc indicated that the mobility of the interlayer ions is strongly improved by thermal activation and the conductivity increased by four orders of magnitude from 363 to 423 K.

A family of novel lanthanide metal–organic frameworks (MOFs) with formula [Ln2(EBTC)1.5(CH3OH)4]·6H2O [EBTC4− = 1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate, Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8) and Dy (9)], have been synthesized via solvothermal reaction. All compounds are isostructural, crystallized in the monoclinic space group P21/n, and show a three-dimensional (4,6)-connected network with Schläfli symbol of {310}. Photoluminescent measurements indicated that 1 and 7 emit the luminescence originating from the intraligand π←π* transition, 2 shows the broadband emission due to allowed 4f–5d transitions, and 4–9 show the emission of typical lanthanide f–f transition via the ligand “antenna effect” in the solid state at ambient temperature. Interestingly, compounds 6 and 8 showed microsecond time-scale fluorescence lifetimes with 0.84 ms for 6 and 0.39 ms for 8, respectively. Such unique spectroscopy features may have applications in biomacromolecule research.

Organic–inorganic hybrid crystals, [1,5-bis(1-methylimidazolium)pentane][PbBr3]2 (1), were achieved through the mutual diffusion of a bi-imidazolium based ionic liquid and PbBr2 solution of DMF in a glass tube. The hybrid solid crystallizes in the orthorhombic space group Fdd2 at room temperature; and is composed of one-dimensional [PbBr3]∞ chains where the neighbouring PbBr6 coordination octahedra are linked together via the face-sharing mode and the inorganic chains are surrounded by organic cations. The hybrid solid exhibits a dielectric anomaly around 443 K and dielectric relaxation above 400 K, the dielectric response mechanism was investigated using variable-temperature X-ray single crystal and powder diffraction as well as DSC techniques. Fascinatingly, this hybrid solid shows dual band emissions, moreover, the fluorescence nature of the two emission bands exhibits a distinct response to temperature, leading to a temperature-dependent fluorescence color, this feature has promising application in the emission temperature-sensing field.

In this study, we prepared sub-micron crystals of one-dimensional (1D) spin-Peierls-type compounds, 1-(4′-R-benzyl)pyridinium-d5 bis(maleonitriledithiolato)nickelate (R = Br or Cl), using a facile method, namely, an acetonitrile solution of each compound was quickly mixed with excess water (an insoluble solvent). This facile method of preparation gave a uniform dispersion of sub-micron crystals with a typical dimension of <1.0 μm. We observed that the reduction in grain size affected the magnetic and phase transition features. With respect to the bulk crystal samples, the powder X-ray diffraction peaks are broadened, the transition temperature (TC) is up-shifted with ΔTC ≈ 1.2 K for R = Br vs. 1.0 K for R = Cl, and the changes of enthalpy and entropy of the phase transition are significantly decreased for the sub-micron crystal samples; in addition, reducing the crystal grain size leads to the onset of a strongly Curie–Weiss-type paramagnetic background and significant temperature-independent paramagnetism.

Structural, magnetic and IR spectroscopic investigations were performed for two charge transfer salts of [Pt(mnt)2]− with 1-N-(4′-R-benzyl)pyridinium-d5 (R = Cl or Br), which experience a magnetic phase transition around 274 K and 270 K, respectively. The crystals of the two salts are isostructural in both high-temperature (HT) phase, crystallized in monoclinic space group P2(1)/c, and low-temperature (LT) phases, crystallized in triclinic space group P. The anions and cations in the two salts form regular stacks in the HT phase, but dimerized ones in the LT phase. The two salts show one-dimensional S = 1/2 Heisenberg antiferromagnetic uniform chain magnetic nature in the HT phase, but spin gap behavior in the LT phase. By comparison of the analogues of [Pt(mnt)2]− with 1-N-(4′-R-benzyl)pyridinium (R = Cl or Br), the different isotopic effects are discussed for the two salts.

Three coordination polymers, {[Zn(L)2]·H2O}n (1), {[Cd(L)2]·H2O}n (2) and {[Mn(L)2]·H2O}n (3) (HL = 2-hydroxy-N-1H-tetrazol-5-ylbenzamide), have been prepared under hydrothermal conditions. X-ray diffraction analysis reveals that compounds 1–3 are isomorphous, showing an interdigitated 3-D framework with 1-D channels. Fluorescence studies show that the emissions of complexes 1–2 are attributed to the ligand π–π* transition. Magnetic studies indicate that compound 3 exhibits antiferromagnetic properties.

•Two isostructural nickel-bis(2-thioxo-1,3-dithiole-4,5-dithiolato) salts show alternating anions and cations layered structure.•There are novel H-bonds of charge-assisted S⋯H between anions and cations layers.•The strong antiferromagnetic coupling occurs between the face-to-face stacked anions within an anion layer.•Two salts show thermal-activated dipolar motion and dielectric relaxation above 175 K.Two new salts of bis(2-thioxo-1, 3-dithiole-4, 5-dithiolato) nickelate monoanion with 4-amino-1-heptylpyridinium (1) and 4-amino-1-nonylpyridinium (2) were prepared and characterized. Two isostructural salts with anion/cation = 1:1 crystallize in space group P-1 with similar cell parameters and packing structures. The anions and cations form alternating layered arrangements, which are connected via charge-assisted S⋯H H-bonds. Within an anion layered alignment, the magnetic exchange is transmitted between the neighboring anions via three types of pathways (face-to-face π–π stack, lateral-to-lateral and head-to-tail S⋯S contacts), where the stronger antiferromagnetic coupling occurs between the face-to-face stacked anions, owing to π-type magnetic orbitals efficiently overlapped, than others and dominates the magnetic nature of 1 and 2. The dielectric and conducting properties were also investigated for two salts in the temperature range of 175–375 K.Two isostructural [Ni(dmit)2]− salts show strong antiferromagnetic interaction within the [Ni(dmit)2]22− π-dimer and thermal-activated dipolar motion and dielectric relaxation above 175 K.

•Two new one-dimensional molecular solid were achieved.•The molecular solids show a magnetostructural transition with TC = ∼335 K.•The magnetostructural transition is not coupled with the dielectric anomaly.•There exists thermal-assisted dielectric relaxation behavior above 280 K in molecular solids.Two new one-dimensional (1-D) molecular solids, [CH2 = CH-BzPy][Pt(mnt)2] (1) and [CH2 = CH-BzPy-d5][Pt(mnt)2] (2) where CH2 = CH-BzPy-d5+ = 1-N-(4-vinylbenzyl) pyridinium-d5 and mnt2− = maleonitriledithiolate, were synthesized and characterized. A structural phase transition undergoes with TC ≈ 335 K in the crystals of 1 and 2, which were confirmed by variable-temperature magnetic susceptibility and DSC measurements. Crystals of 1 and 2 are isostructural in both high- and low-temperature phases. Besides the strong similarity in crystal structures, they show quite analogous magnetic and dielectric features. Above TC, the magnetic behavior is failed to follow the S = ½ Heisenberg linear chain model; below TC, a spin gap is opened for 1 and 2. The thermally-assisted dielectric relaxation occurs above ca. 280 K for 1 and 2, and this relaxation process is related to the dipole motion of the disordered CH2CH groups in the cation under an ac electrical field.Two isostructural one-dimensional S = ½ molecular solids, [CH2 = CH-BzPy][Pt(mnt)2] (1) and [CH2 = CH-BzPy-d5][Pt(mnt)2] (2), show strong similarity in the structural, magnetic and dielectric natures.

Nine molecular substitutional alloys with formula [Cl–BzPy][NixPt1−x(mnt)2] (x = 0.09–0.91) were prepared by mixing the isostructural [Cl–BzPy][Ni(mnt)2] and [Cl–BzPy][Pt(mnt)2] in acetonitrile according to the molar ratio of x/(1 − x), where mnt2− = maleonitriledithiolate, Cl–BzPy+ = 1-(4′-chloro-benzyl)pyridinium. Each alloy compound is isostructural with the parent compounds and shows a magnetic transition; the TC decreases linearly with the molar fraction x, indicating that TC is precisely tunable in this alloy system.

We have successfully achieved crystals of two pseudo-polymorphs, Cd(NMIZ)2(glutarate) (1) and [Cd(NMIZ)2(H2O)(glutarate)]·4H2O (2) where NMIZ represents N-methylimidazole, through controlling the crystallization temperature. The Cd2+ ions form a distorted trigonal prism coordination geometry with two nitrogen atoms from two NMIZ ligands and four oxygen atoms from two carboxylates in 1, while in 2 they form a pentagonal bipyramid coordination geometry with two nitrogen atoms from two NMIZ ligands, four oxygen atoms from two carboxylates and one oxygen atom from coordinated water. The glutarates acted as μ2-bridging ligands, connecting the coordination polyhedra to form coordination polymeric chains in both 1 and 2. The coordination polymeric chains are arranged in parallel arrays and held together via intermolecular van der Waals force in a three-dimensional structure in 1, whereas two-dimensional bi-layers are observed in 2, where the lattice water molecules locate between bi-layers and are archored to the coordination polymeric chain via intermolecular H-bonds. The crystalline phase transformation between 1 and 2 is reversible, as well as the transformation between 2 and 3. The three different crystalline phases show distinct dielectric features. The dielectric permittivity is related to the amount of water in the lattice with the order 2 > 3 > 1. This is because the orientation of polar water molecules in the crystal is able to adjust to the change in the external electric field and transfer the polarization.

Nickel-bis-dithiolene salts, (Bz-Et3N)[Ni(dmit)x(mnt)2−x] (x = 0–2 for 1–3 and mnt2− = maleonitriledithiolate, dmit2− = 2-thioxo-1,3-dithiole-4,5-dithiolate), have been prepared and characterized. These three salts exhibit distinct anion packing structures and magnetic properties. [Ni(mnt)2]− anions, in which the mnt2− ligand has a reduced number of sulfur atoms, form one-dimensional anion stacks in 1. Conversely, [Ni(dmit)2]− anions, in which the dmit2− ligand contains extended SR groups, give rise to a layered structure in 2; the anion layer is composed of co-facial [Ni(dmit)2]− dimers, which are interconnected through short lateral-to-lateral S⋯S and head-to-tail S⋯S contacts. The heteroleptic [Ni(dmit)(mnt)]− anions show one-dimensional anion stacking in 3. Charge-assisted H-bonds are formed between the CN groups of the mnt2− ligands and the H atoms of the cations in 1 and 3 and between the terminal S atoms of the dmit2− ligands and the H atoms of the cations in 2. Both 1 and 3 show antiferromagnetic chain behavior. Within the respective magnetic chains, there are much stronger antiferromagnetic interactions in 3 than in 1, and salt 2 shows antiferromagnetic dimer behavior.

The co-crystal of 4,4′-biphenol with 1,4-diazabicyclo[2.2.2]octane (1) was obtained using a mutual diffusion approach of a two component methanol solution at ambient temperature. DSC measurement detected that 1 undergoes two reversible phase transitions at 182 K/167 K and 236 K/229 K in a heating/cooling cycle. The phases are named: high-temperature (HT), intermediate (IT) and low-temperature (LT) ones in descending order of temperature. Each reversible phase transition corresponds to a dielectric anomaly. The single crystal structure analysis revealed that an isostructural phase transition occurs between the HT and IT phases while a symmetry-breaking structural phase transition undergoes between the IT and LT phases.

Spin-crossover (SCO) occurring in a transition metal complex is the switchable process between two spin states in response to external perturbations such as changes in temperature, pressure or photoexcitation. Such a material has potential applications in switching devices. In this study, we designed a one-dimensional spin-crossover polymer, with a formula of [Fe(NH2-Trz)3](doe)2 where NH2-Trz = 4-amino-1,2,4-triazole and doe = sodium dodecyl sulfonate, and fabricated its monodisperse nanoparticles using a facile precipitation route. The nanoparticles aggregate from plate-shaped nanocrystals and their size dimensions fall in the range of 200–300 nm. The SCO polymer undergoes a thermal reversible spin transition near room temperature which is important for practical applications. The spin transition shows ca. 13 K hysteretic loops and is associated with a color change. The SCO polymer nanoparticles were pressed under ca. 8 MPa static pressure to give a good transparent disc with a thickness of ca. 1 mm; such a disc displays a pink-violet color at ambient temperature and a yellowish color above 45 °C. This SCO material has potential applications in the field of thermochromic devices.

•The light-sensitivity of octacyanometalate is used to prepare new complex.•The light-induced reaction mechanism of octacyanometalate is speculated.•The obtained 3D complex shows a rare five-coordinated environment of Mn.Under light irradiation, (Bu3NH)3[MoV(CN)8]·2H2O reacting with MnClO4·6H2O and NH4SCN leads to the formation of a new three-dimensional cyano-bridged bimetallic complex {(NH4)2[MnII(CH3OH)4][MnII(DMF)]2[MoIV(CN)8]2}∞ (1). X-ray crystallographic analysis reveals that complex 1 crystallizes in a monoclinic space group and contains two different coordination configurations around MnII ions in an asymmetric unit. Specifically, one is six-coordinated while the other is five-coordinated. The magnetic investigation shows that the paramagnetic behavior is only ascribed to MnII ions because MoV has been reduced into diamagnetic MoIV.A three-dimensional octacyanomolybdate complex of {(NH4)2[MnII(CH3OH)4][MnII(DMF)]2[MoIV(CN)8]2}∞ was obtained by light-induced synthesis, which could not be prepared by traditional methods that always keep the reactants in dark. This complex shows a rare five-coordinated environment of Mn in it and its magnetic properties were investigated.

•Inorganic-organic hybrid contains iodoplumbate chain•Hybrid exhibits dielectric anomaly•Hybrid shows semiconductor emissionAn inorganic–organic hybrid [tetrabutylammonium][PbI3] crystallizes in tetragonal space group I-42d, which inorganic components form one-dimensional (1D) face-sharing iodoplumbate chain. This hybrid shows a novel dielectric anomaly around 125 °C. The variable-temperature single crystal and powder X-ray diffraction (PXRD) measurements revealed that the dielectric anomaly arises from the disorder–order transformation of tetrabutylammonium. The hybrid emits orange-red luminescence, ascribed to the semiconductor emission of 1D [PbI3]∞ chain.Inorganic–organic hybrid, [tetrabutylammonium][PbI3], with one-dimensional face-sharing iodoplumbate chain shows novel dielectric anomaly and semiconductor emission.

Proton-conducting materials show important technological applications as key components in energy conversion, electrochemical sensing and electrochromic devices; the exploration for new types of proton-conducting materials is crucial for the development of efficient electrochemical devices. In this study, we investigated the proton transport nature of an inorganic–organic hybrid crystal of open-framework cobalt phosphate, (C2N2H10)0.5CoPO4. The structure of the hybrid crystal consists of the [CoPO4]−∞ anionic framework, and the proton carriers, H2en2+ cations (en = ethylenediamine), are located in the pores to compensate the negative charges of the inorganic framework. The open-framework is thermally stable up to 653 K (380 °C) at least, and also shows superior water stability. The open-framework exhibits negligible conductance in an anhydrous environment even at 473 K; however, there is evident water-assisted proton conduction. The conductivity reaches 2.05 × 10−3 S cm−1 at 329 K and 98% RH. Such high proton conductivity can compete with numerous state-of-the-art MOFs/PCPs-based proton conductors, and this material has promising applications in diverse electrochemical devices.

Proton conducting materials have important technological applications as key components in electrochemical devices, including fuel cells, electrochemical sensors, electrochemical reactors and electrochromic displays. And the exploration of novel proton conducting materials is significant for the development of efficient electrochemical devices. In this study, we have investigated the proton conductance of an open-framework manganese(II) phosphite, (NH4)0.59(H3O)1.41Mn5(HPO3)6 (1). The open-framework manganese(II) phosphate shows superior water-stability and excellent thermal stability. There was intrinsic water-assisted proton conductivity with σ = 3.94 × 10−4 S cm−1 at 328 K and 98% RH. Furthermore, composite membranes have further been fabricated using polyvinylidene fluoride (PVDF) and 1, labeled as 1@PVDF-X, where the symbol X represents the mass percentage of 1 (as X%) in the composite membrane and X = 10–55%. The composite membranes display good mechanical performance and durability for practical applications, and the proton conductivity of 1@PVDF-55 reaches 3.32 × 10−5 S cm−1 in deionized water at 336 K.

An iodoplumbate-based hybrid, [C7-Apy][PbI3] (1), where C7-Apy+ = 1-heptyl-4-aminopyridinium, was prepared using a simple solution process. Three sequential phase transitions occur in the range of 402–443 K. In both the lowest and highest temperature phases, hybrid crystal 1 is composed of discrete [Pb2I6]∞ twin chains surrounded by C7-Apy+ cations. The connectivity between PbI6 octahedra within a [Pb2I6]∞ twin chain and the arrangement of cations are quite difference between the lowest and highest temperature phases. Hybrid crystal 1 shows switchable ion conductivity due to the structural phase transition and white light emission attributed to the broad band semiconductor emission of the twin chain. The former functionality has potential application in ion conductor devices; the single-phase white light emitter is a useful material in low-cost, easily-made, high-efficiency white light-emitting diodes.

Organic–inorganic hybrid crystals, [1,5-bis(1-methylimidazolium)pentane][PbBr3]2 (1), were achieved through the mutual diffusion of a bi-imidazolium based ionic liquid and PbBr2 solution of DMF in a glass tube. The hybrid solid crystallizes in the orthorhombic space group Fdd2 at room temperature; and is composed of one-dimensional [PbBr3]∞ chains where the neighbouring PbBr6 coordination octahedra are linked together via the face-sharing mode and the inorganic chains are surrounded by organic cations. The hybrid solid exhibits a dielectric anomaly around 443 K and dielectric relaxation above 400 K, the dielectric response mechanism was investigated using variable-temperature X-ray single crystal and powder diffraction as well as DSC techniques. Fascinatingly, this hybrid solid shows dual band emissions, moreover, the fluorescence nature of the two emission bands exhibits a distinct response to temperature, leading to a temperature-dependent fluorescence color, this feature has promising application in the emission temperature-sensing field.

A coordination polymer (CP) of Mg2+ with 1,3,5-benzenetricarboxylate (BTC3−) was synthesized using a solvothermal method. The Mg-CP, with a formula of Mg3(BTC)(HCOO)3(DMF)3, crystallizes in the trigonal space group P, with cell parameters of a = b = 13.972(5) Å, c = 8.090(5) Å and V = 1367.6(11) Å3, and shows a lamella structure built from planar rosette-type hexanuclear architectures. The Mg-CP emits intense blue fluorescence arising from π* → π transition of intra-ligand of BTC3− with 21.69% quantum yield, yet it exhibits poor stability to water. The composites of Mg-CP with hydrophobic polyvinylidene fluoride (PVDF) were sequentially prepared by mechanically mixed, tableted and annealed processes, which showed good compatibility between Mg-CP and PVDF, high hydrostability, and intense blue emission. This study suggests a simple but efficient method to solve the drawbacks of some functional CPs unstable to water and to promote them as practical applications in the field of functional materials.

A clathrate NH4Br@HKUST-1 has been prepared by means of soaking the metal–organic-framework, HKUST-1, in ammonium bromide saturated ethanol solution at ambient temperature. Both NH4Br@HKUST-1 and HKUST-1 show the same framework structure. The formula of the clathrate is approximately expressed as Cu3(BTC)2(NH4Br)1.15. The thermal stability of the metal–organic framework is not affected by incorporating ammonium bromide into its pores. The impedance spectra measurements were performed for both NH4Br@HKUST-1 and HKUST-1 in anhydrous and selected relative humidity environments, disclosing that the conductivity of NH4Br@HKUST-1 is enhanced by three/four orders of magnitude under the same conditions with respect to HKUST-1. This study provided an efficient strategy to achieve new high conductivity proton transport materials.

A two-dimensional, mixed-valence [Ni(dmit)2] compound, [C8-Apy]2[Ni(dmit)2]3 (1) (where dmit2− = 2-thioxo-1,3-dithiole-4,5-dithiolate and Apy+ = 4-amino-1-alkylpyridinium), was prepared and its structure was fully characterized. The molecular solid displays a layered structure along the crystallographic c-axis with a [Ni(dmit)2] layer constructed from alternating straight chains of [Ni(dmit)2]0 and two-legged ladder chains of [Ni(dmit)2]1−. Compound 1 shows an antiferromagnetic, spin-dimer with pairwise interaction magnetic behavior and a semiconducting nature in addition to a rapid, clear and stable response of photoconductivity under UV irradiation. The magnetic coupling nature of 1 was analyzed using the ‘broken-symmetry’ density functional theory (DFT) approach. The electronic band structure was calculated using the CASTEP program and was used to investigate the theoretical transport and photoconductive behavior of 1. This work suggests that mixed-valence [Ni(dmit)2] compounds have great potential as the building blocks for new photoconductor based materials.

Multifunctional materials that display different physical properties in a single phase can be utilized in multifunctional devices that are capable of performing more than one task simultaneously. In this study, we synthesized a novel multiple phase transition charge transfer salt [4′-tBu-BzPy][Ni(mnt)2] (4′-tBu-BzPy+ = 4′-tert-butylbenzyl-pyridinium, mnt2− = maleonitriledithiolate) by incorporating a tert-butyl group to control the rotational dynamics in the crystal and to pre-program the amphidynamic [Ni(mnt)2]− magnetic lattice. This salt experienced a two-step structural transformation to give three separate high, immediate and low temperature phases. Interestingly, two structural transformations were coupled to both hysteretic magnetic phase transitions at 187/192 K and 94/96 K, and to dielectric anomalies. These results will assist the design and preparation of novel multiple phase-transition materials harboring technologically important magnetic and dielectric properties.

A family of novel lanthanide metal–organic frameworks (MOFs) with formula [Ln2(EBTC)1.5(CH3OH)4]·6H2O [EBTC4− = 1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate, Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8) and Dy (9)], have been synthesized via solvothermal reaction. All compounds are isostructural, crystallized in the monoclinic space group P21/n, and show a three-dimensional (4,6)-connected network with Schläfli symbol of {310}. Photoluminescent measurements indicated that 1 and 7 emit the luminescence originating from the intraligand π←π* transition, 2 shows the broadband emission due to allowed 4f–5d transitions, and 4–9 show the emission of typical lanthanide f–f transition via the ligand “antenna effect” in the solid state at ambient temperature. Interestingly, compounds 6 and 8 showed microsecond time-scale fluorescence lifetimes with 0.84 ms for 6 and 0.39 ms for 8, respectively. Such unique spectroscopy features may have applications in biomacromolecule research.

The intercalated kaolinite with potassium acetate (K-KAc), with ca. 91.9% intercalation ratio, was prepared. Thermogravimetric and variable-temperature X-ray powder diffraction analyses disclosed that a small amount of water is easily absorbed into the interlayer space of the K-KAc. The previously reported phase with the 14.2 Å interlayer distance is actually the hydrous K-KAc, which has an approximate formula of Al2Si2O5(OH)4·0.5KAc·0.25H2O. The crystal structures of hydrous and anhydrous phases of K-KAc were simulated in the density functional theory framework, demonstrating that the interactions between the K+ and acetate ions and the inner surface of kaolinite are significantly strengthened in the anhydrous phase with regard to the hydrous phase. The ionic conductivity of K-KAc indicated that the mobility of the interlayer ions is strongly improved by thermal activation and the conductivity increased by four orders of magnitude from 363 to 423 K.

In this study, a new two-dimensional Pb2+-based coordination polymer (CP), [Pb2(EBTC)(DMSO)3] (1), where H4EBTC is 1,1′-ethynebenzene 3,3′,5,5′-tetracarboxylic acid, was synthesized under solvothermal conditions. Structural analysis reveals that 1 crystallizes in the monoclinic space group C2/m, where two crystallographically different Pb2+ ions show a coordination geometry of bicapped trigonal prisms that are connected to a double-chain by the EBTC4− ligands through carboxylate groups along the b-axis direction, and where successive double chains are held together to form a 2D layer via the Pb1 and Pb2 bicapped trigonal prisms sharing one edge or a triangle face along the c-axis direction. Interestingly, CP 1 emitted intense and long-lived greenish phosphorescence in the solid state at ambient conditions, with a quantum yield of 1.5% and a phosphorescence lifetime of 4.17 ms, and the emission mainly arose from the electron transition within the π-type orbitals of the EBTC4− ligand. The emission bands assignment and photophysical process were further discussed according to the calculation of both the electronic band structures and density of states. This study gives a fresh impetus to achieve coordination polymer-based long-lived phosphorescence materials under ambient conditions.

The integrated, highly crystalline and water stable Prussian blue analogue films were successfully fabricated on the porous α-Al2O3, the conducting ITO and the flexible non-woven fabric substrates, respectively, using the self-assembly approach. The proton conduction was investigated for both powdered pellets and the film on the porous α-Al2O3 substrate. This study promotes the practical applications of MOF-based proton conductors in various devices.

Nine molecular substitutional alloys with formula [Cl–BzPy][NixPt1−x(mnt)2] (x = 0.09–0.91) were prepared by mixing the isostructural [Cl–BzPy][Ni(mnt)2] and [Cl–BzPy][Pt(mnt)2] in acetonitrile according to the molar ratio of x/(1 − x), where mnt2− = maleonitriledithiolate, Cl–BzPy+ = 1-(4′-chloro-benzyl)pyridinium. Each alloy compound is isostructural with the parent compounds and shows a magnetic transition; the TC decreases linearly with the molar fraction x, indicating that TC is precisely tunable in this alloy system.

A highly thermally stable CP/MOF, comprised of Mg2+ and H2EBTC2− with the formula of [Mg(H2EBTC)(DMF)2], emits dual band luminescence centered at 376 and 555 nm. The former is assigned to the fluorescence of H2EBTC2− and the latter with 1.63 μs decay lifetime and large Stokes shifts corresponds to the phosphorescence of H2EBTC2−. To the best of our knowledge, this is the first time the ligand-based phosphorescence in a CP/MOF without any heavy atom at room temperature has been observed.

Films of Prussian blue analogue (PBA) Co3[Co(CN)6]2 were fabricated on porous α-alumina, ITO glass, silicon wafer and non-woven fabric substrates via a facile self-assembly method, and were characterized using infrared spectroscopy, X-ray powder diffraction and scanning electron microscope techniques. The films composed of truncated cube-shaped PBA particles are highly oriented with a preferred (100) plane on the glossy and smooth surfaces of ITO glass and silicon wafer, but crystallographically isotropic on the rough surface of porous α-alumina and non-woven fabric substrates. Compact films were achieved on porous α-alumina and surface-functionalized ITO glass. Reversible solvatochromism/vapochromism was discovered and investigated for the powdered and thin-film PBA samples. Such peculiar solvatochromism/vapochromism is related to the process of the adsorbed solvent molecules replacing the coordinated water molecules in octahedral Co2+–(N)4(H2O)2. The change of the Co2+ ion’s coordination atmosphere leads to the variation of crystal field strength, as a result, the d–d transitions within the Co2+ ions are altered to give rise to a color change.