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Abstract: Two new 3D zinc carboxylates Zn2(suc)(ina)2 (1) (suc=succinate, ina=isonicotinate) and Zn2(fum)(ina)2 (2) (fum=fumarate) have been synthesized under the hydrothermal condition and characterized by the single crystal X-ray diffractions. Both complexes 1 and 2 featuring the [Zn2(CO2R)4] subunit (SBU) formed by mixed tetracarboxylate, interlinked by carboxylate-aromatic amine ligands (ina) to construct a 2D (4,4) sheet, which are further pillared by rigid or flexible dicarboxylates ligands (suc or fum) into 3D framework. The topology of 1 and 2 can be related to the cubic α-Po twofold interpenetrating lattice. Thermogravimetric analyses demonstrate the similar one-step thermal decomposition process with the tolerate temperature ca. 400°C of complexes 1 and 2 resulted from the parallel structure motifs and high stability of them. [Copyright &y& Elsevier]

Abstract: A new cobalt(II) phosphonate, [enH2]0.5[Co(pa)(H2O)]·H2O (1) (H3pa=hydroxy-phosphono-acetic acid, HO2CCH(OH)PO3H2; en=ethylenediamine), has been hydrothermally synthesized and structurally characterized. Compound 1 has a honeycomb-like layer structure which is composed of CoO6 octahedra and μ3-pa ligands with the protonated en and lattice water molecules stabilized between the layers. Magnetic studies indicate that 1 shows weak ferromagnetic behavior, spin-glass behavior, and metamagnetic behavior. [Copyright &y& Elsevier]

cobalt(A novel three dimensional (3D) polymer, [Co2(hypa)2(4,4′-bipy)] (1) (H2hypa = hydroxy-phenyl-acetic acid, 4,4′-bipy = 4,4′-bipyridine), featuring pentacoordinate, dimeric cobalt(II) as subunits have been prepared, which shows low-dimensional antiferromagnetic ordering blow 15.2 K (TN). [ABSTRACT FROM AUTHOR]

• Study an evacuation problem considering the dynamics and routing of buses and cars. • A bi-directional multilane conflict-eliminating cell transmission model (BCECTM). • A new evacuation optimization model is proposed by integrating the BCECTM and SDVRP. • The model describes trajectories and dynamics, and improves bus capacity utilization. This paper studies dynamic evacuation optimization in the context of a new cell transmission with the split delivery vehicle routing problem (SDVRP) of multiple modes of buses and cars. A bi-directional multilane conflict-eliminating cell transmission model (BCECTM) is proposed to simulate the mixed traffic dynamic evacuation process on links and at intersections. The method of SDVRP is applied to manage dynamic evacuation demands and optimize the routing of multiple modes. The mechanisms of vehicle transmission, traveling trajectory, and residual capacity updating are depicted based on the models of BCECTM and SDVRP; thus, a mathematical programming model aiming to minimize the total evacuation time is established by integrating the BCECTM and SDVRP. A genetic algorithm with a chromosome position-coding scheme is designed to solve the evacuation optimization model. Case studies show that the proposed model can reasonably assign evacuation demands that gather at some sites around the event to, and effectively evacuate people by, buses and cars so that the capacities of buses are fully utilized, and can generate optimal vehicle traveling trajectories to improve the evacuation performance. Furthermore, the evacuation and congestion degree under different demand levels and different arrival distributions are analyzed with meaningful conclusions. [ABSTRACT FROM AUTHOR]

• Highly diastereoselective synthesis of molecualr rotor from molecualr motor. • First example of TGA on molecular motor. • Non-equilibrium vs equilibrium operation of molecular machines. Developing stereoselective synthetic method is very important to access chiral molecular devices. We herein demonstrate how a proton initiated stereoselective enamine-imine tautomerization converts a molecular motor into a simple rotor with high diastereoselectivity (>20:1 dr). NMR and X-ray crystallography were used to elucidate the structures of both the motor and rotor unambiguously. The activated motion of the rotor about its central single bond was studied from variable temperature NMR (293–423 K) and DFT calculations provide evidence of the origin of diastereoselectivity of enamine-imine tautomerization as well as the rotor dynamics with barrier as high as 39.3 kcal/mol. Results from our work may benefit future design towards stereocontrolled and adaptive molecular machines. [ABSTRACT FROM AUTHOR]

Herein we report a comparative study for a series of cheap, robust, and efficient water oxidation electrocatalysts made up of the heptanuclear disk clusters ([M 7 (OH) 6 L 6 ](ClO 4 ) 2 ·solvent (M = Co, Ni or mixed Co-Ni) and L = 2-ethoxy-6-(N-methyl-iminomethyl)phenolate) for renewable energy production. Experiments performed on the three complexes immobilized on conductive substrates reveal the catalytic efficiency in the order Co-Ni > Ni > Co based on threshold and overpotentials as well as electro-impedance parameters. Remarkably, the Co-Ni mixed metal cluster shows low onset overpotential of only 270 mV and a small Tafel slop of 53.4 mV/dec. Moreover, the Faradaic efficiency exceeds 90% for the Co-Ni cluster. Their characteristics are major improvements on those reported for transition metal complexes. These complexes could be proposed as promising electrocatalysts for water oxidation reaction. [ABSTRACT FROM AUTHOR]

Abstract: Hydrothermal treatment of a mixture of H3imdc (4,5-imidazoledicarboxylic acid), Na2SO4, Dy(NO3)3·6H2O and NaOH generated a novel inorganic–organic hybrid framework, {[Dy2(SO4)(Himdc)2(H2O)5]·H2O}n (1). Its crystal structure contains alternately arranged 1D left- and right-handed helical {Dy(Himdc)}n chains, each helical chain is composed of alternately arranged Dy(1) and Dy(2) ions connected by Himdc2– with bis(bidentate) linking mode. Every three helical chains are bridged by inorganic SO4 2− anions, which link Dy3+ ions in a tris(monodentate) mode to form a 3D framework. Compound 1 displays intense yellow photoluminescence corresponding to the characteristic 4F9/2 → 6HJ transitions of the Dy3+ ion. [Copyright &y& Elsevier]

Abstract: Removal of a basic dye (Methylene Blue) from aqueous solution was investigated using a cross-linked succinyl-chitosan (SCCS) as sorbent. The chemical structures of chitosan and its derivatives were testified by FT-IR. X-ray diffraction, DTG analysis and swelling measurements were conducted to clarify the characteristics of the chemically modified chitosan. The effect of process parameters, such as pH of the initial solution, and concentrations of dyes on the extent of Methylene Blue (MB) adsorption was investigated. The Langmuir isotherm model was used to fit the equilibrium experimental data, giving a maximum sorption capacity of 289.02mg/g at 298K. Kinetic studies showed that the kinetic data were well described by the pseudo-second-order kinetic model. Thermodynamic parameters such as enthalpy change (ΔH°), free energy change (ΔG°) and entropy change (ΔS°) were determined to be −25.32kJmol−1, −6.76kJmol−1 and −62.36Jmol−1 K−1, respectively, which leads to a conclusion that the adsorption process is spontaneous and exothermic. [Copyright &y& Elsevier]

Abstract: To utilize the contribution of introduced amino groups to the adsorption of an anionic dye (eosin Y), a batch adsorption system was applied to study the adsorption of eosin Y from aqueous solution by tetraethylenepentamine (TEPA) modified chitosan (TEPA–CS). Experiments were carried out as a function of particle size, initial pH, agitation rate, adsorbent dosage, agitation period, temperature and initial concentration of eosin Y. The Langmuir and Freundlich models were used to fit the adsorption isotherms. From the values of correlation coefficients (R 2), it was observed that the experimental data fit very well to the Langmuir model, giving a maximum sorption capacity of 292.4mg/g at 298K. Kinetic studies showed that the kinetic data were well described by the pseudo-second-order kinetic model. The thermodynamic study revealed negative value of enthalpy change (ΔH°) and free energy change (ΔG°), indicating spontaneous and endothermic nature of the adsorption of eosin Y on to TEPA–CS. [Copyright &y& Elsevier]

Abstract: In this study, chitosan was cross-linked with ethylenediamine (EDA) to prepare an outstanding sorbent for the removal of anionic dye eosin Y from aqueous solution. FTIR, DTG, XPS and zeta potential analysis were used to characterize the sorbent. The effect of particle size, solution pH, agitation rate, temperature, adsorbent dosage (50–500mg/L), contact time (10min–24h) and initial concentration of dye (50–300mg/L) on the adsorption process was investigated. Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants, and the data fitted well with Langmuir model with a maximum adsorption capacity of 294.12mg/g at 25°C. Kinetic studies followed the pseudo second-order rate model, which indicated that the chemisorption is the rate-limiting step. Thermodynamic parameters such as enthalpy change (ΔH°=−5.004kJ/mol), free energy change (ΔG°<0) and entropy change (ΔS°=−11.656J/(molK)) indicate the exothermic and spontaneous nature of adsorption. [Copyright &y& Elsevier]

Abstract: A unique [Co13(mosao)8(Hmosao)6]·(ClO4)4·3DMF·MeOH·3H2O (1, H2mosao=3-methoxysalicylaldoxime) supercluster has been synthesized by a method of solvothermal reaction. The [Co13(μ 2-O)8(μ 3-O)6(μ 2-O–N)2(μ 3-O–N)8]4+ core is highly conjugated butterfly-like disc, which can be considered as fourteen distorted defective cubes sharing the neighboring faces one another. The electrospray ionization mass spectrometry (ESI-MS) analysis of 1 strongly suggests that Co13 cluster also exists in solution and maintains a conformation similar to that in the crystal structure, indicating that the significant stability of 1 in solution. Magnetic measurements of 1 reveal antiferromagnetic behaviors resulting from the cooperative magnetic coupling through multiplicate monoatomic oxygen and –N–O– exchange bridges and the odd number of spins result in relatively effective noncompensated moments at very low temperature. [Copyright &y& Elsevier]

Abstract: A new 2D coordination polymer with the formula [Co4(μ3-OH)2(H2nip-2H)2(H2nip-H)2(bpe)2] n (1) (H2nip=5-nitro-isophthalic acid, bpe= trans-1,2-bis(4-pyridyl)ethylene), has been hydrothermally synthesized and structurally characterized. The structure of 1 is built around uncommon, rhombic {Co4} clusters with double T d and double O h Co(II) geometries, which are extended into 2D network by the rigid deprotonated H2nip and bpe bridges. Magnetic property study indicates there is weak antiferromagnetic coupling interaction between Co(II) ions, which mainly arises from the antiferromagnetic coupling interaction in the tetramer, based on the nature of the μ3-hydroxyl group and syn–syn carboxylate-bridged modes. [Copyright &y& Elsevier]

[Display omitted] A pillared-layer MOF constructed from two matched and quite long linkers of thiadiazole functionalized dicarboxylate and dipyridine, exhibits selective adsorption of CO 2 over CH 4 and N 2. This work provides new insight into the pore surface modification and broadens the horizons to rational design mixed-ligands MOF with demanding pore environment for specific application. • Well-matched long mixed linkers facilitate highly porous and rigid pillared-layer MOF. • The Co(II)-MOF is structural stable in water, pH = 1 HCl and pH = 12 NaOH aqueous solution. • The 1D narrowed channels with rich thiadiazole groups contribute to selective CO 2 adsorption. The high-efficiency CO 2 separation using metal–organic frameworks (MOFs) is crucial in CO 2 capture and subsequent conversion for green carbon cycling, yet challenged by rational optimizing the size, shape, sorption site and microenvironment of the pores. The new MOFs with formula [Co 2 (btd) 2 (dpbt) 2 ]·3DMF (1) is constructed from two matched long linkers of 4,4′-(benzoic[i1,2,5]thiadiazole-4,7-diyl)dibenzoic (H 2 btd) and 4,7-di(4-pyridyl)-2,1,3- benzothiadiazole) (dpbt) under solvothermal condition. The compound processes 3-fold interpenetrated pillared-layer frameworks, generating 1D channels sized at 10.8 × 8.2 Å2 and with exposed thiadiazole groups for improved CO 2 sorption. The framework is quite rigid confirmed by quite limited changes in crystallographic parameters during solvent exchange and guest removal in single-crystal-to-single-crystal (SC-SC) fashion. The Co(II)-MOF exhibits unprecedented good chemical stability in aqueous solution with pH ranging from 1 to 12, retaining unchanged PXRD patterns for more than 24 h. The activated MOFs show better adsorption for CO 2 over N 2 with selectivity of 18.8 at 273 K, benefitted from the merits of narrow 1D channels and appending Lewis basic sites on the pore surface. [ABSTRACT FROM AUTHOR]

A pillar-layered MOF is constructed from 1,2,4-triazole extended (4,4)-grid layer, which is pillared by inclined dicarboxylate. Benefited from the good structure stability in various organic solvents, water, and either acidic or alkaline condition, the highly fluorescent 1 is used to selectively sensing Fe3+ with a low detection limit in methanol and aqueous solution, through quenching effect stemming from weak binding between uncoordinated N atoms in the thiadiazole and Fe3+. [Display omitted] • A pillared-layer MOFs is constructed from (4,4)-grid layer pillared by inclined dicarboxylate. • The MOFs is structural stable in water, pH = 3 HCl and pH = 12 NaOH aqueous solution. • Selective sensing of Fe3+ with low detection limit is realized by fluorescence quenching. The pillared-layer Metal–Organic Framework (MOF) enjoys good tunability and rich functionality, yet highly relies on rational combination of mixed ligands. A new MOF formulated as [Zn 2 (trz) 2 (btdb)]·4DMF (1 , trz = 1,2,4-triazole, H 2 btdb = 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl) dibenzoic acid) is constructed from a [Zn 2 ] node based (4,4)-grid layer that pillared by inclined a highly fluorescent dicarboxylate linkers. The rigid [Zn 2 (trz) 2 ] layer coupled with hydrogen bonding encompassed Zn-carboxyl linkage endow the MOF desired high stability. The crystalline structure of 1 maintains well in harsh conditions including pH = 3 HCl and pH = 12 NaOH aqueous solution for more than 24 h. With high void fraction of 42.7%, the interconnected 3D channels sized at 4.0–8.8 Å guarantee sufficient exposure of thiadiazole in the pillar ligand as potential sensing site. With bright fluorescence of 1 , Fe3+ ions can be selectively and specifically detected in both aqueous and non-aqueous solution through quenching mechanism, given a detection limit of 3.1 and 17.0 μM in methanol and H 2 O solution, respectively. [ABSTRACT FROM AUTHOR]