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A layered dysprosium–dianthracene framework shows photo-switchable structures and emission colors, which enables the manipulation of MOF-based heterostructured crystals for applications in rewritable photonic barcodes and fatigue-resistant photoactuators.

The proton conductivity of a single crystal of Co–Co phosphonate along the c axis is 1.5 times higher than that of isostructural Ni–Co phosphonate, originating from the slight pKa difference of water molecules coordinated to Co2+ or Ni2+ centers.

Complexes α-Dy(depma)3Cl3 (α-DyCl), β-Dy(depma)3Cl3 (β-DyCl), and β-Dy(depma)3Br3 (β-DyBr) are reported. α-DyCl and β-DyCl are polymorphs showing distinct magnetic dynamics and luminescence properties.

Photosensitive lanthanide-based single-molecule magnets (Ln-SMM) are very attractive for their potential applications in information storage, switching, and sensors. However, the light-driven structural transformation in Ln-SMMs hardly changes the coordination number of the lanthanide ion. Herein we report for the first time that X-ray (λ = 0.71073 Å) irradiation can break the coordination bond of Dy-OH2 in the three-dimensional (3D) metal-organic framework Dy2(amp2H2)3(H2O)6∙4H2O (MDAF-5), where the {Dy2(OPO)2} dimers are crosslinked by dianthracene-phosphonate ligands. The structural transformation proceeds in a single-crystal-to-single-crystal (SC-SC) fashion, forming the new phase Dy2(amp2H2)3(H2O)4∙4H2O (MDAF-5X). The phase transition is accompanied by a significant change in magnetic properties due to the alteration in coordination geometry of the DyIII ion from a distorted pentagonal bipyramid in MDAF-5 to a distorted octahedron in MDAF-5-X.

Inspired by the exciting physical/chemical properties in metal-organic frameworks (MOFs) of the redox-active tetrathiafulvalene (TTF) ligands, nickel bis(dithiolene-dibenzoic acid), [Ni(C2S2(C6H4COOH)2)2], has been designed and developed as an inorganic analogue of the corresponding TTF-type donors (such as tetrathiafulvalene-tetrabenzoate, TTFTB), where a metal site (Ni) replaces the central C═C bond. In this work, [Ni(C2S2(C6H4COOH)2)2] and In3+ have been successfully assembled into a three-dimensional MOF, (Me2NH2+){InIII-[Ni(C2S2(C6H4COO)2)2]}·3DMF·1.5H2O (1, DMF = N,N-dimethylformamide), with satisfying chemical and thermal stabilities. With the combination of reversible redox activity and unsaturated metal sites originated from [Ni(C2S2(C6H4COOH)2)2], 1 showed a significantly enhanced performance in electrocatalytic CO2 reduction compared with the isomorphic MOF, (Me2NH2+)[InIII-(TTFTB)]·0.7C2H5OH·DMF (2, with TTFTB ligand). More importantly, by mimicking the active [NiS4] sites of formate dehydrogenase and CO-dehydrogenase, a prominently higher conversion rate and Faradaic efficiency (FE), with FEHCOO- increasing from 54.7% to 89.6% (at -1.3 V vs RHE, jHCOO- = 36.0 mA cm-2), were achieved in 1. Mechanistic investigations further confirm that [NiS4] can serve as a CO2 binding site and efficient catalytic center. This unprecedented effect of redox-active nickel dithiolene-based MOF catalysts on the performance of electroreduction of CO2 provides an important strategy for designing stable and efficient crystalline enzyme-mimicking catalysts for the conversion of CO2 into high-value chemical stocks.

Controllable synthesis of uniformly distributed nanowires of coordination polymers with inherent physical functions is highly desirable but challenging. In particular, the combination of chirality and magnetism into nanowires has potential applications in multifunctional materials and spintronic devices. Herein, we report four pairs of enantiopure coordination polymers with formulae S-, R-Dy(cyampH)3 ⋅ CH3 COOH ⋅ 2H2 O (S-1, R-1), S-, R-Dy(cyampH)3 ⋅ 3H2 O (S-2, R-2), S-, R-Dy(cyampH)2 (C2 H5 COO) ⋅ 3H2 O (S-3, R-3) and S-, R-Dy(cyampH)3 ⋅ 0.5C2 H5 COOH ⋅ 2H2 O (S-4, R-4) [cyampH2 =S-, R-(1-cyclohexylethyl)aminomethylphosphonic acids], which were obtained depending on the pH of the reaction mixtures and the specific carboxylic acid used as pH regulator. Interestingly, compounds 3 were obtained as superlong nanowires, showing 1D neutral chain structure which contains both phosphonate and propionate anion ligands. While compounds 1, 2 and 4 appeared as block-like crystals, superhelices and nanorods, respectively, and exhibited similar neutral chain structures containing only phosphonate ligand. Slow magnetization relaxation characteristic of single-molecule magnet (SMM) behavior was observed for compounds S-1 and S-3. Theoretical calculations were performed to rationalize the magneto-structural relationships.

Developing proton–conducting electrolytes that are usable over a wide temperature range (25–150 °C) is highly desirable to enhance the efficiency of fuel cells for on-board automotive applications....

Layered heterometallic 5f-3d uranyl phosphonates can exhibit unique luminescent and/or magnetic properties, but the fabrication and properties of their 2D counterparts have not been investigated. Herein we report three heterobimetallic uranyl phosphonates, namely, [(UO

Ultrathin nanosheets of luminescent metal-organic frameworks or coordination polymers have been widely used for sensing ions, solvents and biomolecules but, as far as we are aware, not yet used for temperature sensing. Herein we report two luminescent uranyl phosphonates based on 2-(phosphonomethyl)benzoic acid (2-pmbH3), namely (UO2)(2-pmbH2)2 (1) and (H3O)[(UO2)2(2-pmb)(2-pmbH)] (2). The former has a supramolecular layer structure, composed of chains of corner-sharing {UO6} octahedra and {PO3C} tetrahedra which are connected by hydrogen bonds between phosphonate and carboxylic groups. Compound 2 possesses a unique 2D anionic framework structure, where the inorganic uranyl phosphonate chains made up of {UO7} and {PO3C} polyhedra are cross-linked by 2-pmb3- ligands. The carboxylic groups of 2-pmbH2- ligands are pendant on the two sides of the layers and form hydrogen bonds between the layers. Both compounds can be exfoliated in acetone via a top-down freeze-thaw method, resulting in nanosheets of two-layer thickness. Interestingly, the photoluminescence (PL) of 1 and 2 is highly temperature sensitive. Variable temperature PL studies revealed that compounds 1 and 2 can be used as thermometers in the temperature ranges 120-300 K and 100-280 K, respectively. By doping the nanosheets into polymer matrix, 1-ns@PMMA and 2-ns@PMMA were prepared. The PL intensity of 1-ns@PMMA is insensitive to temperature, unlike that of the bulk sample. While 2-ns@PMMA exhibits similar temperature-dependent luminescence behaviour to its bulk counterpart, thereby enabling its potential application as a thermometer in the temperature range 100-280 K.

Chiral transcription from the molecular level to the macroscopic level by self-organization has been a topic of considerable interest for mimicking biological systems. Homochiral coordination polymers (CPs) are intriguing systems that can be applied in the construction of artificial helical architectures, but they have scarcely been explored to date. Herein, we propose a new strategy for the generation of superhelices of 1D CPs by introducing flexible cyclohexyl groups on the side chains to simultaneously induce interchain van der Waals interactions and chain misalignment due to conformer interconversion. Superhelices of S- or R-Tb(cyampH)3·3H2O (S-1H, R-1H) [cyampH2 = S- or R-(1-cyclohexylethyl)aminomethylphosphonic acid] were obtained successfully, the formation of which was found to follow a new type of “chain-twist-growth” mechanism that had not been described previously. The design strategy used in this work may open a new and general route to the hierarchical assembly and synthesis of helical CP materials., Superhelices of terbium phosphonates formed following a new type of “chain-twist-growth” mechanism involving flexible cyclohexyl groups.

Previous proton conducting research mainly focused on the proton conducting behavior in the bulk phase. This work studied the proton conduction in the MOF grain surface. We prepared UiO-66-NH2 part...

Inspired by the exciting physical/chemical properties in metal-organic frameworks (MOFs) of the redox-active tetrathiafulvalene (TTF) ligands, nickel bis(dithiolene-dibenzoic acid), [Ni(C

Artificial smart materials with switchable multifunctionality are of immense interest owing to their wide application in sensors, displays and memory devices. Lanthanide complexes are promising multifunctional materials integrating optical and magnetic characteristics. However, synergistic manipulation of different physical properties in lanthanide systems is still challenging. Herein we designed and synthesized a mononuclear complex [DyIII(SCN)3(depma)2(4-hpy)2] (1), which incorporates 9-diethylphosphonomethylanthracene (depma) as a photo-active component and 4-hydroxypyridine (4-hpy) as a polar component. This compound shows several unusual features: (a) reversible thermo-responsive phase transition associated with the order–disorder transition of 4-hpy and SCN−, which leads to thermochromic behavior and dielectric anomaly; (b) reversible photo-induced dimerization of anthracene groups, which leads to synergistic switching of luminescence, magnetic and dielectric properties. To our knowledge, compound 1 is the first example of lanthanide complexes that show stimuli-triggered synergistic and reversible switching of luminescence, magnetic and dielectric properties., [DyIII(SCN)3(depma)2(4-hpy)2] (1) shows reversible thermo-induced phase transition associated with thermochromism and dielectric anomaly and photo-induced dimerization with synergistic switching of luminescence, magnetic and dielectric properties.

Metal-organic frameworks containing responsive organic linkers are attractive for potential applications in sensors and molecular devices. Herein we report three cobalt(II) phosphonates incorporating responsive dianthracene linkers, namely, Co2 (amp2 H2 )2 (H2 O)4 ⋅ 6H2 O (MDAF-1), Co2 (amp2 )(H2 O)4 ⋅ 2H2 O (MDAF-2) and Co(amp2 H2 ) ⋅ 2H2 O ⋅ 0.5DMF (MDAF-3), where amp2 H4 is pre-photodimerized 9-anthrylmethylphosphonic acid. MDAF-1 shows a layer structure in which dinuclear Co2 (PO3 H)2 units are inter-connected by dianthracene ligands. In MDAF-2 and MDAF-3, inorganic chains of corner-sharing {CoO4 } (or {CoO6 }) and {PO3 C} are cross-linked by dianthracene ligands into 3D frameworks. All compounds underwent thermo-induced phase transitions, first the de-solvation and then the de-dimerization of dianthracene (as well as the release of the remaining solvent molecules for MDAF-2 and -3), associated with magnetic changes. MDAF-1 can be exfoliated into single-layer nanosheets in water which show light-triggered luminescent changes.

Four new p-aminobenzenesulfonate organotin complexes, [(n-Bu3Sn)(O3SC6H3-NH2-4)]n (1), [(n-Bu2Sn)4(O)2(OH)2(O3SC6H4-NH2-4)2] (2), [(Me2Sn)4(O)2(OH)2(O3SC6H4-NH2-4)2] (3) and [{(n-BuSn)12O14(OH)6}(O3SC6H4-NH2-4)2·3C4H8O2] (4·diox), were synthesized by reaction of p-aminobenzenesulfonic acid with tributyltin oxide, dibutyltin oxide, dimethyltin oxide and monobutyltin oxide, respectively. These complexes were characterized by elemental analysis, FT-IR, NMR (1H, 13C, 119Sn) spectroscopy as well as single-crystal X-ray diffraction. The crystal structure of complex 1 reveals that it is a 1D zig-zag chain structure and further interlinked into a 2D network by intermolecular interaction (N-H⋯O). The structure analysis indicates that complexes 2 and 3 are the ladder-like structure including three alternate Sn2O2 rings, and further result in the formation of a 3D supramolecular architecture for 2 and a 2D supramolecular network for 3 by extensive hydrogen-bonding interactions (O-H⋯O, N-H⋯O). Complex 4 exhibits a dodecanuclear organooxotin cages, which are connected into a hydrogen-bonded 2D structure. Furthermore, complexes 1-4 were evaluated for their in vitro cytostatic activity against the human lung cancer cells (A549) and the human hepatocellular carcinoma cells (HepG-2). The preliminary screen shows that organotin derivatives with increasing number n-butyl group exhibitsignificantly higher cytostatic activity, and much higher than methyl group.

Incorporating transition metal ions into uranyl phosphonate frameworks can bring not only new structure types but also interesting physical or chemical properties. Herein we report two heterometallic uranyl carboxyphenylphosphonates, namely, [Cu2(UO2)3(2-pmbH)2(2-pmb)2(H2O)4]·2H2O (1) and [Mn3(UO2)6(2-pmb)6(H2O)8]·10H2O (2) [2-pmbH3 = 2-(phosphonomethyl)benzoic acid]. Compound 1 shows a two-dimensional layered structure in which uranyl-PO3 chains are linked by {Cu2O2} dimers. Within the uranyl-PO3 chain, {UO6} tetragonal bipyramids and edge-sharing dimers of {UO7} pentagonal bipyramids are connected by edge-sharing {PO3C} tetrahedra. Compound 2 possesses a unique 3D open framework structure, where the Mn-layers are pillared by uranyl-PO3 chains. The uranyl-PO3 chain in 2 is very different from that in 1, which contains trimers of edge-sharing {UO7} and {UO8} polyhedra and {PO3C} linkages. While the Mn-layer consists of chains of {MnO6} octahedra bridged alternatively by carboxylate and phosphonate groups, which are inter-connected by organic moieties of 2-pmb3-. The thermally activated sample of 2 displays strong adsorption capability toward NH3. Magnetic studies revealed dominant antiferromagnetic interactions between the metal centers in both compounds.