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The efficient hydrogenation of biomass-derived levulinic acid (LA) to value-added γ-valerolactone (GVL) based on nonprecious metal catalysts under mild conditions is crucial challenge because of the intrinsic inactivity and instability of these catalysts. Herein, a series of highly active and stable carbon-encapsulated Co/ZnO@C-X (where X = 0.1, 0.3, 0.5, the molar ratios of Zn/(Co+Zn)) heterojunction catalysts were obtained by in situ pyrolysis of bimetal CoZn MOF-74. The optimal Co/ZnO@C-0.3 catalyst could achieve 100% conversion of LA and 98.35% selectivity to GVL under mild conditions (100 °C, 5 bar, 3 h), which outperformed most of the state-of-the-art catalysts reported so far. Detailed characterizations, experimental investigations, and theoretical calculations revealed that the interfacial interaction between Co and ZnO nanoparticles (NPs) could promote the dispersibility and air stability of the active Co

A new concave shaped high refractive index plasmonic sensor with a micro-channel is proposed in this work, which comprises an analyte channel in the core hole. The sensor is elaborately designed to reduce the interference effect from the metal coating. Furthermore, the impact of the proposed structure on the sensitivity is also investigated by engineering the geometric parameters using the finite element method. We select gold as the plasmonic material in this theoretical study because it is widely used to fabricate plasmonic and metamaterial devices due to its chemical stability and compatibility. According to wavelength interrogation technique, simulations results show that this sensor can obtain maximal wavelength sensitivity of 10,050 nm/refractive index unit. In view of the excellent indicators of this device, it has important development potential in chemical and biological research fields.

Highly selective separation and purification of acetylene (C2H2) from ethylene (C2H4) and carbon dioxide (CO2) are daunting challenges in light of their similar molecule sizes and physical properties. Herein, we report a two-dimensional (2D) stable metal–organic framework (MOF), NUM-11 ([Cu(Hmpba)2]·1.5DMF) (H2mpba = 4-(3,5-dimethyl-1H-pyrazol-4-yl)benzoic acid), with sql topology, stacked together through π–π interactions for efficient separation of C2H2 from C2H4 and CO2. The 2D-MOF material offers high hydrolytic stability and good purification capacity; especially, it could survive in water for 7 months, even longer. This stable MOF selectively captures C2H2 from mixtures containing C2H4 and CO2, as determined by adsorption isotherms. The ideal adsorbed solution theory selectivity calculations and transient breakthrough experiments were performed to verify the separation capacity. The low isosteric heat of NUM-11a (desolvated NUM-11) (18.24 kJ mol–1 for C2H2) validates the feasibility of adsorbent regeneration with low energy footprint consumption. Furthermore, Grand Canonical Monte Carlo simulations confirmed that the pore surface of the NUM-11 framework enabled preferential binding of C2H2 over C2H4 and CO2 via multiple C–H···O, C–H···π, and C–H···C interactions. This work provides some insights to prepare stable MOF materials toward the purification of C2H2, and the water-stable structure, low isosteric heat, and good cycling stability of NUM-11 make it very promising for practical industrial application.

Selective hydrogenation of CO2 to methanol is a "two birds, one stone" technology to mitigate the greenhouse effect and solve the energy demand-supply deficit. Cu-based catalysts can effectively catalyze this reaction but suffer from low catalytic stability caused by the sintering of Cu species. Here, we report a series of zeolite-fixed catalysts Cu/ZnOx(Y)@Na-ZSM-5 (Y is the mass ratios of Cu/Zn in the catalysts) with core-shell structures to overcome this issue and strengthen the transformation. Fascinatingly, in this work, we first employed bimetallic metal-organic framework, CuZn-HKUST-1, nanoparticles (NPs) as a sacrificial agent to introduce ultrasmall Cu/ZnOx NPs (∼2 nm) into the crystalline particles of the Na-ZSM-5 zeolite via a hydrothermal synthesis method. The catalytic results showed that the optimized zeolite-encapsulated Cu/ZnOx(1.38)@Na-ZSM-5 catalyst exhibited the space time yield of methanol (STYMeOH) of 44.88 gMeOH·gCu-1·h-1, much more efficient than the supported Cu/ZnOx/Na-ZSM-5 catalyst (13.32 gMeOH·gCu-1·h-1) and industrial Cu/ZnO/Al2O3 catalyst (8.46 gMeOH·gCu-1·h-1) under identical conditions. Multiple studies demonstrated that the confinement in the zeolite formwork affords an intimate surrounding for the active phase to create synergies and avoid the separation of Cu-ZnOx interfaces, which results in an improved performance. More importantly, in the long-term test, the Cu/ZnOx(1.38)@Na-ZSM-5 catalyst exhibited constant STYMeOH with superior durability benefitted from its fixed structure. The current findings demonstrate the importance of confinement effects in designing highly efficient and stable methanol synthesis catalysts.

Carbon-encapsulated metal-organic framework (MOF) composite is one kind of emerging new catalyst with high efficiency and has gained much attention. However, for this kind of composite catalyst, the key to improving its catalytic activity and durability is to realize the effective dispersion of MOF nanoparticles (NPs) and enhance the interaction between MOF NPs and the carbon matrix, which remain a significant challenge. Herein, ultrafine MOF NPs within multichamber carbon spheres (MOF@MCCS), for the first time, have been rationally synthesized by a two-step double-solvent strategy for high-performance catalysts. The precise loading of guest MOFs can be achieved by adjusting the multichamber structure and calcination extent of the multichamber polymer (MCP), and the particle size of MOFs can be as low as 13.2 nm. Due to the formation of abundant carbon defects in the pyrolysis process of MCPs, the special structure and synergistic effect make the material exhibit higher catalytic activity and durability. More importantly, this method is universal and can be extended to different MOF systems. The two-step double-solvent strategy not only prepares a unique structure of MOF@MCCS-type host-guest-encapsulated catalysts but also provides a new idea for the design of high-efficiency catalysts with better performance and higher durability.

In this paper, we report a lamellar-structured low-alloy transformation-induced plasticity (TRIP) steel; the microstructure of the steel consists of alternate lamellae of intercritical ferrite and reverted austenite on microscale, with the latter consisting of bainitic ferrite laths and retained austenite films on nanoscale. Such a microstructure was produced by a heat treatment process similar to that for producing conventional TRIP-assisted steels, i.e. intercritical annealing followed by austempering. Nevertheless, quenched martensite rather than a mixture of ferrite and pearlite was used as the starting structure for intercritical annealing to form austenite, and the resulting austenite was then transformed to bainite by austempering treatment. This steel exhibits much enhanced strength-ductility combinations as compared with those conventional polygonal-structured low-alloy TRIP steels.

5-Hydroxymethylfurfural (HMF) containing C=O, C-O, and furan ring functional groups is an important platform chemical derived from C

The separation of ethylene (C2H4) from C2 hydrocarbons is considered as one of the most difficult and important processes in the petrochemical industry. Heat-driven cryogenic distillation is still widely used in the C2 hydrocarbons separation realms, which is an energy intensive process and takes up immense space. In response to a greener, more energy-efficient sustainable development, we successfully synthesized a multifunction microporous Mg-based MOF [Mg2(TCPE)(µ2-OH2)(DMA)2].solvents (NUM-9) with C2H6/C2H2 selectivity based on a physical adsorption mechanism, and with outstanding stability; especially, it is stable up to 500 °C under an air atmosphere. NUM-9a (activated NUM-9) shows good performances in the separation of C2H6/C2H2 from raw ethylene gases. In addition, its actual separation potential is also examined by LAST and dynamic column breakthrough experiments. GCMC calculation results indicate that the unique structure of NUM-9a is primarily conducive to the selective adsorption of C2H6 and C2H2. More importantly, compared with C2H4, NUM-9a prefers to selectively adsorb C2H6 and C2H2 simultaneously, which makes NUM-9a as a sorbent have the capacity to separate C2H4 from C2 hydrocarbon mixtures under mild conditions through a greener and energy-efficient separation strategy.

The propane (C3H8)-trapping adsorption behavior is considered as a potential performance to directly produce high-purity propylene (C3H6). Herein, we report an ultramicroporous Mn-based metal-organic framework (NUM-7) with a reverse C3H8-selective behavior in the low-pressure area. The pore structure of this material possesses more electronegative aromatic benzene rings for the stronger binding affinity to C3H8, and the material shows outstanding reverse ideal adsorbed solution theory (IAST) selectivity values. Single-component sorption isotherms preliminarily show the reverse adsorption behavior in the low-pressure part, and the moderate heat of adsorption further confirms this performance and exhibits less energy consumption for regeneration. In addition, the purification effect for the C3H8/C3H6 mixture is evaluated by the IAST selectivity and transient breakthrough curves, and the GCMC calculation results reveal that the fascinating C3H8-trapping behavior mainly depends on the multiple C-H···π interactions. Moreover, because C3H6 is the desired target product, the interesting C3H8-selective adsorption behavior of NUM-7 may provide its potential for one-step purification of C3H6, and this work can provide the method of developing C3H8-selective materials for the purification of C3H6.

The aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a promising renewable monomer to produce bio-based polymers such as polyethylene furanoate (PEF), has recently emerged as the subject of increasing interest. Here, holey 2 D Mn2 O3 nanoflakes were obtained by a facile thermal treatment of a Mn-based metal-organic framework (MOF) precursor. The structural and morphological properties of the nanoflakes were characterized by powder XRD, FTIR, SEM and TEM to explore the formation process. It was inferred that the linker loss in the MOF precursor and the oxidation of the Mn cation induced by the heat-treatment in air were responsible for the formation of holey 2 D Mn2 O3 nanoflakes. The specific morphology and redox cycle of the Mn cation on the surface endowed the synthesized nanoflakes with promising performance on the selective oxidation. The obtained nanoflakes calcined at 400 °C (M400) afforded over 99.5 % yield of FDCA at complete conversion of HMF, which is superior to the catalytic activity of commercial Mn2 O3 and activated MnO2 . To our knowledge, Mn2 O3 exhibiting such a high performance on the aerobic oxidation of HMF to FDCA has not yet been reported. Based on the investigation of the experimental parameters, a plausible reaction mechanism was proposed.

The preparation of metal nanocomposite catalysts with MOFs as precursors has attracted extensive attention, as the design and preparation of catalysts by this method could maximize the advantages of the precursors and ensure the stability of the catalysts as much as possible. Here, a benzimidazole-modified Cu/Co bimetal-MOF as a precursor was used to synthesize a Cu-nanowire@Quasi-MOF material via a simple and low-cost thermal decomposition strategy for the first time. Experimental evaluation suggested that the Co-MOF part in Cu/Co bimetal-MOF was a morphology retainer, and the special channel composition of the Quasi-MOF played a space-confined role in the formation of the unique Cu-nanowires. Based on the detailed investigation, a possible formation mechanism was proposed. Furthermore, Cu-nanowire@Quasi-MOF exhibited excellent catalytic performance and good stability in the selective oxidation of benzyl alcohol in air. This study demonstrated that using MOFs as a precursor, by adjusting the calcination temperature and adding heteroatoms, can control the morphology of metal nanoparticles (MNPs) in MOF derivatives, reduce agglomeration and enhance catalytic activity, which will be a promising approach to in situ preparation of complex metal nanocomposites.

Low temperature derived carbon electrodes are employed to fabricate low cost hole transport layer free perovskite solar cells, in which perovskite films annealed in glovebox and ambient air are used as the absorbers, respectively. Results suggest that the air annealed sample has bigger crystal grains and higher crystallinity, and the existence of a small amount of lead iodide which passivates grain boundaries contributes to a lower trap density. As a result, a maximum power conversion efficiency (PCE) of 13.07% was obtained on the air annealed device, which is higher than those of devices annealed in glovebox (11.25%). Furthermore, the stability of unencapsulated devices stored in wet (with humidity around 90% ± 5%) air atmosphere are investigated and the results prove that our devices exhibit good stability. In addition to rigid devices, flexible perovskite solar cells are also fabricated using the same procedure. The highest PCE of 11.53% is demonstrated on the champion flexible device, and 69% of its initial PCE can be maintained even after 2000 bending cycles with a bending radius of 2 mm. Our work provides a promising and simple rout for low-cost, air-stable, high-efficiency carbon perovskite solar cells for both large area production and flexible electronic devices industry.

Two new metal-drug complexes constructed from non-toxic zinc and theophylline (TPL), an anti-asthmatic active drug, have been introduced into a release system based on matrices of hydroxypropylmethylcellulose (HPMC) and microcrystalline cellulose (MC). The release rate of TPL from the metal-drug complexes could be controlled by the amount of MC added, and the release mechanism changed from anomalous transport to Fickian diffusion.

The vehicle semi-active suspension system plays an important role in improving the driving safety and ride comfort by adjusting the coefficients of the damping and spring. The main contribution of this paper is the proposal of a PPO-based vibration control strategy for a vehicle semi-active suspension system, in which the designed reward function realizes the dynamic adjustment according to the road condition changes. More specifically, for the different suspension performances caused by different road conditions, the three performances of the suspension system, body acceleration, suspension deflection, and dynamic tire load, were taken as the state space of the PPO algorithm, and the reward value was set according to the numerical results of the passive suspension, so that the corresponding damping force was selected as the action space, and the weight matrix of the reward function was dynamically adjusted according to different road conditions, so that the agent could have a better improvement effect at different speeds and road conditions. In this paper, a quarter–car semi-active suspension model was analyzed and simulated, and numerical simulations were performed using stochastic road excitation for different classes of roads, vehicle models, and continuously changing road conditions. The simulation results showed that the body acceleration was reduced by 46.93% under the continuously changing road, which proved that the control strategy could effectively improve the performance of semi-active suspension by combining the dynamic changes of the road with the reward function.

As a kind of MOFs, cage-based MOFs usually carry large voids and small windows, which are advantageous to the storage of small molecules that remain kinetically trapped inside the cages (confinement effect). By adjusting the size of windows via reticular synthesis, the cage-based MOFs can selectively capture and separate the suitable size molecules. Here, considering angle-directed and face-directed strategies, a novel multicage-based MOF NUM-3 with a new (3,4,5)-connected topology was successfully constructed in the mixed-ligands assembly. In the framework of NUM-3, there exist four different kinds of cages, which exhibit diverse polyhedral configurations. The four kinds of cages in the order ABCDDCBA as the minimum repeat unit form a 1D tortuous channel along the c axis. Based on the structure characteristics that the 1D channel exhibits different inner diameter (from 4.0 to13.0 A), NUM-3a (actived NUM-3) can capture CO2 over C2H4 and C2H6 by the size selectivity (the empirical kinetic diameters: CO2 < ...

A porous metal–organic framework [Cu2L(H2O)2]·7DMF·4H2O (UTSA-90, H4L = 2′,5′-dimethoxy-[1,1′:4′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid) functionalized with methoxy groups has been successfully constructed and structurally characterized, which is isoreticular to NOTT-101. A single crystal structure determination reveals that the incorporation of bulky methoxy groups can efficiently split the large pores and channels of NOTT-101a into smaller ones within UTSA-90. Compared with NOTT-101a, the activated UTSA-90a exhibits the significantly enhanced C2H2 (214 vs 184 cm3 g–1) and CO2 (125 vs 83 cm3 g–1) adsorption capacities at 295 K and 1 bar. It is worth noting that the CO2 uptake of UTSA-90a represents the highest reported for all the NbO-type metal-organic frameworks (MOFs). In addition, UTSA-90a also shows a significant enhancement in adsorptive selectivities for the separation of C2H2/CH4, CO2/CH4, and CO2/N2 mixtures at ambient conditions. This work indicates that introducing bulky functional group...

In this paper, cationic polycarboxylate superplasticizer has been synthesized by using room temperature process with HPEG, AA, DAC and 3-S as the main raw materials. We investigated the effect of the dosage of different raw materials on the dispersing property of polycarboxylate superplasticizer, and we knew that AA: DAC: HPEG: 3-S = 4.5: 0.05: 1: 0.12 was the best molar ratio, the synthesized cationic polycarboxylate superplasticizer had excellent dispersity and mud resistance, and it was superior to commercially available ordinary polycarboxylate superplasticizer.

Isostructural CoII and MnII organic frameworks with anionic frameworks and counterions (Me2NH2)+, namely {[M2Cl2(BTC)4/3]·(Me2NH2)+2·4/3H2O}n (M = Co (1) and Mn (2)), have been constructed by one-pot synthesis. Complexes 1 and 2 take paddle-wheel-like dinuclear metal cluster-based three-dimensional structures. Thermogravimetric analysis and variable-temperature powder X-ray diffraction spectra suggested that 1 displays better thermal stability than 2. Both exhibit relatively high proton conductivities at 65% relative humidity (RH) and room temperature (σ > 2.5 × 10–4 S cm–1); however, complex 1 possesses the better cycling capability and stability with Ea = 0.21 eV under 65% RH.

A diaminotriazine-decorated porphyrin-based microporous hydrogen-bonded organic framework has been successfully prepared and characterized using single crystal X-ray diffraction analysis. Its activated phase exhibits permanent porosity, gas separation, and proton conductivity under humid conditions.

Steel-fiber reinforced polymer (FRP) composite bar (SFCB) is a new composite material with good corrosion resistance and designable post-yield stiffness. Substitution of steel bar with SFCB can greatly increase the durability and ultimate capacity associated with seismic performance. First, the method and main results of the experiment are briefly introduced, then a simplified constitutive model of composite bar material was applied to simulate the seismic behaviors of the concrete beams reinforced with SFCBs by fiber element modeling. The simulation results were found to be in good agreement with test results, indicating that the finite element model is reasonable and accurate in simulating the seismic behaviors of beams reinforced with SFCB. Based on the numerical simulation method, a parametric study was then conducted. The main variable parameters were the FRP type in composite bars (i.e., basalt, carbon FRP and E-glass FRP), the concrete strength, basalt FRP (BFRP) content in SFCBs and shear span ratio. Seismic behaviors such as load-displacement pushover curves, seismic ultimate capacity and its corresponding drift ratio of the SFCBs reinforced concrete beams were also evaluated. The results showed that (1) the fiber type of the composite bar had a great impact on the mechanical properties of the beam, among which the beam reinforced with BFRP composite bar has higher seismic ultimate capacity and better ductility. With the increase of the fiber bundle in the composite bar, the post-yield stiffness and ultimate capacity of the component increase and the ductility is better; (2) at the pre-yield stage, concrete strength has little influence on the seismic performance of concrete beams while after yielding, the seismic ultimate capacity and post-yielding stiffness of specimens increased slowly with the increase in concrete strength, however, the ductility was reduced accordingly; (3) as the shear span ratio of beams increased from 3.5 to 5.5, the seismic ultimate capacity decreased gradually while the ultimate drift ratio increased by more than 50%. Through judicious setting of the fiber content and shear span ratio of the composite bar reinforced concrete beam, concrete beams reinforced with composite bars can have good ductility while maintaining high seismic ultimate capacity.

Organic donor-acceptor systems have attracted much attention due to their various potential applications. However, the rational construction and modulation of highly ordered donor-acceptor systems could be a challenge due to the complicated self-assembly process of donor and acceptor species. Considering the well-defined arrangement of species at the molecule level, a crystalline host-guest system could be an ideal platform for the rational construction of donor-acceptor systems. Herein, it is shown how the rational construction of highly tunable donor-acceptor materials can be achieved based on a crystalline host-guest platform. Within the well-established metal-organic framework NKU-111 as the crystalline host enabled by the relatively stable coordination-directed assembly, the introduction and arrangement of guest molecules in the crystals allow the rational construction of the NKU-111⊃guest donor-acceptor system. The donor-acceptor interaction in the systems can be readily modulated with different guest molecules, which can be justified by the well-demonstrated guest-dependent characteristics. Accordingly, the NKU-111⊃guest reveals highly tunable donor-acceptor properties such as charge-transfer-based emissions and electrical conductivity. This work indicates the potential of crystalline host-guest systems as an ideal platform for systematic investigations of donor-acceptor materials.

Flexible metal-organic frameworks (MOFs) receive much attention owing to their attractive properties that originate from their flexibility and dynamic behavior, and show great potential applications in many fields. Here, recent progress in the discovery, understanding, and property investigations of flexible MOFs are reviewed, and the examples of their potential applications in storage and separation, sensing, and guest capture and release are presented to highlight the developing trends in flexible MOFs.

The reaction of polydentate ligand Bis-tris propane {(CH2OH)3CNH(CH2)3NHC(CH2OH)3} with Ln(NO3)3·6H2O and Fe3O precursor resulted in the formation of a series of Fe6Ln2 nanoclusters. Magnetic measurements indicate that the Fe6 core exhibits ferrimagnetic behavior, and slow magnetic relaxation was observed in Fe6Dy2 and Fe6Tb2.

Two highly porous metal–organic frameworks are successfully constructed through the assembling of Co/Ni ions and mixed ligands. From the contribution of the uncoordinated tetrazolate N atoms of the ligand the two complexes show high CO2adsorption capacities, serving as potential CO2adsorption materials.

Solvent induced structural diversities from a cup-shaped Co8 cluster (1) in methanol to a Co8 cluster-based co-crystal chain (2) in ethanol/n-propanol and a Co8 cluster-based chain (3) in n-butanol under the same stoichiometric ratio of reactants have been reported. In situ ligand conversion has taken place and the new ligand is captured within the metallic core. Magnetic analyses indicate that theses complexes exhibit distinct magnetic behaviours at low temperature.

The separation and purification of light hydrocarbons (LHs) mixtures is one of the most significantly important but energy demanding processes in the petrochemical industry. As an alternative technology to energy intensive traditional separation methods, such as distillation, absorption, extraction, etc., adsorptive separation using selective solid adsorbents could potentially not only lower energy cost but also offer higher efficiency. The need to develop solid materials for the efficiently selective adsorption of LHs molecules, under mild conditions, is therefore of paramount importance and urgency. Metal-organic frameworks (MOFs), emerging as a relatively new class of porous organic-inorganic hybrid materials, have shown promise for addressing this challenging task due to their unparalleled features. Herein, recent advances of using MOFs as separating agents for the separation and purification of LHs, including the purification of CH4 , and the separations of alkynes/alkenes, alkanes/alkenes, C5 -C6 -C7 normal/isoalkanes, and C8 alkylaromatics, are summarized. The relationships among the structural and compositional features of the newly synthesized MOF materials and their separation properties and mechanisms are highlighted. Finally, the existing challenges and possible research directions related to the further exploration of porous MOFs in this very active field are also discussed.

A polynuclear manganese complex composed of alternating cyclic tetramer and monomer has been solvothermally prepared and magnetically characterized. Magnetic analyses indicate that the title compound shows spin-canting behavior.

Hydrothermal synthesis of Gd2O3 and iminodiacetic acid (H2IDA) yields a three-dimensional (3D) complex {[Gd2(IDA)3]·2H2O}n (1) including Gd16 macrocycles. Magnetic investigation indicates the presence of weak antiferromagnetic interaction between GdIII ions and a large magnetocaloric effect with −ΔSmmax = 40.6 J kg–1 K–1.

By combining carbon woven fabric with thermoplastics grains, a thermo-stamping process is proposed for forming parts with complex double curvatures in one step, to implement the affordable application of fiber reinforced composites in high volume merchandises such as automotive industry. In the proposed thermo-stamping process, laminated carbon woven fabrics with thermoplastic grains are heated, and then transferred rapidly to a preheated mould for thermo-stamping, and cooled down to form the carbon fiber reinforced composite part. Various thermoplastics such as PP, PA6 and ABS are used as matrix material in the composite part. Experimental results including shear angle distribution in the fabric, deformed boundary profile of fabric with different original fiber orientation and forming defects are presented. It is demonstrated that high quality parts can be obtained with the proposed forming process, and defects are controllable. By using the proposed process and laminated structures, it is feasible to implement the high-volume and low-cost manufacturing of fiber reinforced composite parts.

A facile template-free sonochemistry-assisted microwave method was successfully developed for the synthesis of mesoporous hydroxyapatite nanoparticles (MHN) in a short time. The prepared MHN were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and N2 adsorption–desorption isotherms. TEM images showed a clear rod-like morphology with length of 50–100 nm and width of about 20 nm. XRD and FTIR indicated a typical hydroxyapatite phase with high crystallinity. N2 adsorption–desorption isotherms revealed an irregular mesoporous structure. Judging from the values calculated from N2 isotherms, the specific surface area and pore volume obviously decreased after the sintering process. In a typical example, the specific surface area, pore volume, and pore size of MHN before and after calcination were 79.74 m2/g, 0.46 cm3/g, 2.7 nm and 45.41 m2/g, 0.22 cm3/g, 2.8 nm, respectively. In addition, MHN could be synthesized in a period of time as short as 10 min. Further investigation indicated that microwave radiation played a dominant role in the emergence of mesoporous structure, while ultrasound irradiation acted as a supporting role. Based on the above results, a possible mechanism of formation of mesoporous hydroxyapatite has been proposed.

A new manganese(II) coordination polymer, [Mn2(L1)4/3(L2)2]n (1) (L1 = 4′-(4-pyridyl)-4,2′:6′,4″-terpyridine, H2L2 = (4-phenyl)-2,6-bis(4-carboxyphenyl)pyridine), has been prepared and structurally characterized. Complex 1 is a 2-fold interpenetrated three-dimensional framework, which to our knowledge represents the first interpenetration example of coordination framework with unique (3,6)-connected loh1 topology. Furthermore, the magnetic properties and photocatalytic activity have been investigated. As a result, complex 1 displays a weak antiferromagnetic interaction among the Mn(II) centers and good photocatalytic activity for the degradation of methyl orange solution under ultraviolet light irradiation.

Aiming at exploring the effect of substituting groups of three structurally related ligands, 5,6-diethyl-pyrazine-2,3-dicarboxylic acid (H 2 L 1 ), 5,6-diphenyl-pyrazine-2,3-dicarboxylic acid (H 2 L 2 ), and dibenzo[ f,h ]quinoxaline-2,3-dicarboxylic acid (H 2 L 3 ), seven new coordination polymers constructed from these three substituted dicarboxylate ligands, {[Zn(L 1 )(H 2 O) 3 ]·2H 2 O} ∞ (1) , {[Cd 2 (L 2ʹ ) 4 (H 2 O)]·3H 2 O} ∞ (2) , [Zn(L 2 )(CH 3 OH)] ∞ (3) , {[Zn(L 2 )(H 2 O) 2 ]·H 2 O} ∞ (4) , {[Zn(L 2ʹ )]·H 2 O} ∞ (5) , [Zn 2 (L 3 )(DMF) 4 ] ∞ (6), [Zn(L 3 )(2,2ʹ-bipy)(H 2 O)] ∞ (7), have been prepared and structurally characterized. 1 is a 1D chain structure in which Zn II ion is six-coordinated with octahedron geometry. 2 is also a 1D chain structure in which there are two crystallographically independent Cd II ions in the asymmetric unit and exist transformative L 2ʹ ligands in the resulting complex. 3 and 4 both possess 2D layer network with the same (4, 8 2 ) topology, while the two complexes take different coordination modes during the forming of the compounds. 5 has a 1D chain structure based on the transformative L 2ʹ ligand in which Zn II ion is five-coordinated with bipyramidal geometry. 6 and 7 both have 1D chain structure constructed from L 3 ligand. Thereinto, Zn II ion in 6 is five-coordinated by three oxygen atoms from two individual L 3 ligands and two oxygen atoms from two DMF molecules. While in 7 there are also five coordination sites occupied by two carboxylate oxygen atoms from two L 3 ligands. In addition, the compounds are characterized by elemental analysis, IR spectra. The luminescent properties of the compounds are also discussed and exhibit strong fluorescent emissions in the solid state.

Two series of lanthanide metal–organic frameworks, [Ln(FDA)(OX)0.5(H2O)2]·(H2O) (1Ln) (Ln = Pr 1, Nd 2, Eu 3, Gd 4, Tb 5), [Ln(FDA)(OX)0.5(H2O)2]·(H2O) (2Ln) (Ln = Sm 6, Tb 7, Dy 8, Ho 9, Yb 10) (OX = oxalate), have been prepared by reacting Ln(NO3)3·6H2O with furan-2,5-dicarboxylic acid (H2FDA) at different temperatures under hydrothermal conditions. All the complexes are characterized by elemental analysis, IR, X-ray powder diffraction, and single-crystal X-ray diffraction. Structure analyses show that 1Ln and 2Ln are supramolecular isomerisms. 1Ln possesses a three-dimensional network with monoclinic space group P21/c, whereas 2Ln exhibits a three-dimensional framework with monoclinic space group C2/c. The distinct architectures of these two series of ten complexes indicated that the reaction temperature plays an important role in the formation of such coordination structures. Meanwhile, the photoluminescent properties of 4, 5, 7, and 8 are also investigated in the solid state at room temperature.

In our efforts to investigate the influence of the backbone of different triazole-based bridging ligands on the structure of their metal complexes, four new coordination polymers, {[Cu(L1)2(H2O)2]Cl2}n (1), [Cu(L2)2Cl2]n (2), [Co(L2)2(SCN)2]n (3), and [Cu(L3)2(NO3)2]n (4), (L1 = 1,2-bis(triazol-1-ylmethyl)benzene, L2 = 1,3-bis(triazol-1-ylmethyl)benzene, L3 = 1,4-bis(triazol-1-ylmethyl)benzene), have been synthesized. All the complexes have been structurally characterized by IR, elemental analysis and single-crystal X-ray diffraction. Structural analyses show that 1 and 4 possess 2D coordination networks with (4,4) topology, and 1 shows a diagonal–diagonal inclined interpenetration. 2 and 3 are isostructural and feature 1D double chain, which further connected by C–H···Cl or π···π weak interactions to form 2D supramolecular frameworks. The results show that the structures of ligands (with different non-coordination backbone spacers) play important roles in the formation of such coordination architectures. Furthermore, EPR (Electron Paramagnetic Resonance) spectra of CuII complexes (1, 2, and 4) have been investigated in the solid state at room temperature.

Two new metal-organic frameworks, {[CuLI]·CHCl3}∞(1) and {[HgL(Br)2]4·2CH2Cl2}∞ (2) have been prepared by reacting CuI and HgBr2 with the new flexible ligand L [L = 2,3-Bis(benzimidazol-1-ylmethyl)quinoxaline]. Both complexes have been characterized by elemental analysis, IR, TGA, XRPD, and single crystal X-ray diffraction determination. In 1, the Cu(I) ion takes tetrahedral coordination geometry, and the flexible ligands bridge dinuclear units (Cu2I2) to form a one dimensional (1D) double chain structure. While in 2, the Hg(II) coordinates to two bromine ions and two nitrogen donors of L to form a 1D coordination polymer. The structure differences of the two complexes mainly depend on the geometry of the metal ions and the influence of anions. The coordination features of the ligand have also been primarily investigated by density functional theory (DFT) calculations. In addition, the fluorescent properties of the complexes and free ligand L have been investigated in the solid state at room temperature.

A new supermolecular building blocks (SBBs) based microporous metal–organic framework (MOF) was prepared with both 1,3,5-benzenetricarboxylic acid (H3btc) and 2,4,6-tris(4-pyridyl)-1,3,5-triazine (tpt) as ligands. The obtained CoII MOF reveals an uncommon ftw-a-like structure from the assembly of cubohemioctahedra SBBs under the direction of tpt and exhibits selective gas adsorption properties depending on gas molecule diameter and temperature which might have application in gas separation purposes.

Orthogonal frequency-division multiplexing (OFDM) combines the advantages of high performance and relatively low implementation complexity. However, for reliable coherent detection of the input signal, the OFDM receiver needs accurate channel information. The Doppler shift of fast-fading channels will generate inter-carrier interference (ICI) and, hence, degrade the performance of orthogonal frequency-division multiplexing (OFDM) systems. In this paper, we present regularized total least-squares (RTLS) scheme to eliminate the ICI and noise. A closed-form mathematical expression has been derived to express the channel estimation. It has been shown that the proposed channel estimation and data detect can effectively eliminate the ICI effect.

Four Ag(I) coordination complexes formulated as {[Ag(L1)(ClO4)]}n (1), {[Ag(L1)(NO3)]}n (2), {[Ag(L1)(PF6)]}2 (3) and {[Ag(L2)](ClO4)·CH3OH}n (4), (L1 = 3,6-bis(1-pyrazolyl)pyridazine, L2 = 3,6-bis(3,5-dimethyl-1-pyrazolyl)pyridazine) have been synthesized in the presence of different anions [ClO4− (1) and (4), NO3− (2), PF6− (3)] and structurally characterized by FT-IR spectra, elemental analysis and X-ray diffraction. Studies of X-ray diffraction reveal that complexes 1, 2 and 4 show infinite helical chains, which are the alternate left- and right-handed helical chains. Furthermore, helical chains are arranged to 2D sheet via C–H⋯O (from anion O atoms) hydrogen bonds. As the anion changed to PF6−, a dinuclear molecule is formed in complex 3, further constructing a 2D sheets by C–H⋯F hydrogen bonds. The photoluminescence properties of all the complexes 1–4 have been investigated in the solid state at room temperature.

A series of structurally related rigid imidazole ligands, 1,4-bis(imidazol-1-yl)benzene (L1), 1,4-bis(benzoimidazol-1-yl)benzene (L2), and 4,4′-bis(benzoimidazol-1-yl)biphenyl (L3), have been utilized to construct coordination polymers. The reactions of CdX2 (X = BF4− or ClO4−) with these ligands afford three new three-dimensional networks, {[Cd(L1)3](BF4)2(CHCl3)2}∞ (1), {[Cd(L2)3](ClO4)2(CHCl3)4(CH3OH)2}∞ (2), and {[Cd(L3)3](ClO4)2}∞ (3). Compounds 1−3 are all α-Po metal−organic frameworks (MOFs) based on six-connected CdII nodes which are octahedrally coordinated by six nitrogen atoms of ligand molecules. Complex 2 represents a distorted α-Po framework with noninterpenetration, whereas 1 and 3 both exhibit a double interpenetrating α-Po network. These results suggest that the degree of interpenetration is tunable by ligand modifications, that is, varying the ligand spacer or terminal group. The three complexes exhibit a different void volume in their network. Gas adsorption measurements indicate that 3...

In our efforts to investigate polydentate ligands bearing bulky backbones, we used a bulky ligand, 2,3,6,7-anthracenetetracarboxylic acid (H4ata), to react with ZnII ions under different conditions, yielding four new coordination polymers, {[Zn(ata)0.5(DMF)(H2O)]·DMF·H2O}n (1), {[Zn(ata)0.5(4,4′-bipy)0.5(DMF)]·DMF}n (2), {[Zn(ata)0.5(azpy)0.5(DMF)]·DMF}n (3), and {[Zn(ata)0.5(4,4′-bipy)(DMAC)]·(DMA)0.5}n (4) (DMF = N,N-dimethylformamide, 4,4′-bipy = 4,4′-bipyridine, azpy = 4,4′-azopyridine, DMAC = N,N-dimethylacetamide, DMA = dimethylamine), which were characterized by IR and single crystal X-ray diffraction. Complex 1 forms a two-dimensional (2D) network with (4,4) topology assembled by ata4− ligands and ZnII ions. Complexes 2 and 3 are three-dimensional (3D) frameworks with {83}2{85;10} topology containing infinite 2D networks pillared by 4,4′-bipy and azpy, respectively. Complex 4 takes a 2D structure with (4,4) net containing infinite one-dimensional chains constructed by ZnII ions with 4,4′-bipy and ...

To explore the influence of ligand backbones on the structures of coordination architectures, three structurally related rodlike ligands bearing different backbones, 1,4-bis(benzoimidazol-1-yl)-phenyl (L1), 1,4-bis(imidazol-1-yl)-benzene (L2), and 4,4′-bis(imidazol-1-yl)-biphenyl (L3), have been employed to react with Co(ClO4)2·6H2O, and three three-dimensional interpenetrating coordination polymers, {[Co(L1)2](ClO4)2}∞ (1), {[Co(L2)3](ClO4)2(CHCl3)2}∞ (2), and {[Co(L3)3](ClO4)2}∞ (3), have been obtained under similar conditions. Compound 1 forms a 3-fold interpenetrating network with diamondoid topology based on a tetrahedrally coordinated CoII node, whereas complex 2 takes a double interpenetrating network with α-polonium-type topology and compound 3 exhibits a 3-fold interpenetrating network with β-Sn topology. Compared with the tetrahedrally coordinated CoII node in compound 1, the CoII nodes in compounds 2 and 3 are both octahedrally coordinated. To the best of our knowledge, the 3-fold interpenetrat...

Five new Zn(II) metal–organic coordination polymers, [Zn2(L1)2(Dpq)2]·H2O (1), [Zn(L2)(Dpq)(H2O)] (2), [Zn(L3)(Dpq)(H2O)]2 (3), [Zn(Dpdq)(L3)] (4) and [Zn(Dpdq)(L4)]·H2O (5) (Dpq = dipyrido[3,2-d∶2′,3′-f]quinoxaline, Dpdq = 2,3-di-2-pyridylquinoxaline, H2L1 = benzene-1,2-dicarboxylic acid, H2L2 = benzene-1,3-dicarboxylic acid, H2L3 = benzene-1,4-dicarboxylic acid, H2L4 = biphenyl-4,4′-dicarboxylic acid), have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction analyses. Single-crystal X-ray analyses show that complexes 1–4 possess chain structures which are further assembled to form four three-dimensional (3-D) frameworks by π–π stacking and/or hydrogen-bonding interactions, while a similar chain of 5 has a two-dimensional (2-D) network packed by π–π stacking and hydrogen-bonding interactions. In 1–3, the Dpq ligand takes a chelating coordination mode while the other two nitrogen atoms did not coordinate to the Zn(II) ions. In 4 and 5, the Dpdq ligands have two coordination modes. The structural differences of the benzenedicarboxylate ligands and N-containing rigid/flexible chelating ligands have a great influence on the geometries of the corresponding complexes. This result also shows that intramolecular/intermolecular weak interactions play an important role in the formation of supramolecular networks, especially in linking low-dimensional entities into high-dimensional supramolecular frameworks. In addition, complexes 1 and 3–5 exhibit blue emission in the solid state at room temperature.