On the basis of an asymmetric, conjugated, partially or wholly deprotonated 5-(pyridin-3-yl)-1H-pyrazole-3-carboxylic acid (H2ppc), five new complexes [Co2(ppc)2(H2O)]n (1), {[Co2(Hppc)4]·[Co(4,4′-bipy)2(H2O)4]·(OH)2·10H2O}n (2), [Co2(Hppc)4(4,4′-bipy)]n (3), {[Co(ppc)(pbbbm)]·H2O}n (4) [pbbbm = 1,4-bis(benzimidazole-1-ylmethyl)benzene)], and [Co(Hppc)2(mbbbm)]2 (5) [mbbbm = 1,3-bis(benzimidazole-1-ylmethyl)benzene)] have been synthesized and characterized magnetically and structurally. Polymer 1, which has the Schläfli symbol (42·62·82)2(42·6·83)2, is a three-dimensional (3D) network. Polymer 2 includes a mononuclear subunit and an infinite two-dimensional (2D) framework subunit, while polymer 3 is a 2D sheet structure. Polymer 4 is characterized by a one-dimensional double ladder-like chain structure. Complex 5 possesses a binuclear structure. Magnetization data for 1 with the Co2 units show the antiferromagnetic coupling in the Co2 units. No long-range magnetic ordering is observed for 1. 2, 3, and 5 display weak antiferromagnetic exchange interactions. For 4 with the similar Co2 units, it also exhibits antiferromagnetic coupling in the Co2 units, and the M(H) curve is consistent with the antiferromagnetic nature in the Co2 units. Variable temperature magnetic studies reveal that 2, 3, and 5 display weak antiferromagnetic interactions. The observed magnetization values, which were ∼2.5 Nβ at high field for 2, 3, and 5, are in accordance with the value anticipated for single uncompensated S = 1/2 spin.

•A new (3,4,5)-connected 2D MOF based on the tetranuclear Cu4 units has been obtained.•Magnetic studies reveal magnetic interactions associated with the hydroxo bridges arising from different Cu-OH-Cu angles.•No magnetic ordering is observed for 1.Based on an asymmetric imidazole-1-acetic acid (Hima), a new polynuclear complex [Cu2(ima−)(SO42 −)(H2O)(OH−)]n 1 has been synthesized and characterized structurally and magnetically. Polymer a two-dimensional (2D) structure based on the tetranuclear Cu4 units, which displays a (3,4,5)-connected topology. The magnetic susceptibility data is dominated by magnetic interactions associated with the hydroxo bridges arising from different Cu-OH-Cu angles, which is in agreement with magneto-structural correlations found in the literature relative to such bridges in Cu(II) complexes.Complex 1 shows (3,4,5)-connected 2D structure based on the tetranuclear Cu4 units. Magnetic studies reveal magnetic interactions associated with the hydroxo bridges arising from different Cu-OH-Cu angles.Download high-res image (206KB)Download full-size image

In this work, RuO2 honeycomb networks (RHCs) and hollow spherical structures (RHSs) were rationally designed and synthesized with modified-SiO2 as a sacrificial template via two hydrothermal approaches. At a high current density of 20 A g–1, the two hierarchical porous RuO2·xH2O frameworks showed the specific capacitance as high as 628 and 597 F g–1; this is about 80% and 75% of the capacitance retention of 0.5 A g–1 for RHCs and RHSs, respectively. Even after 4000 cycles at 5 A g–1, the RHCs and RHSs can still remain at 86% and 91% of their initial specific capacitances, respectively. These two hierarchical frameworks have a well-defined pathway that benefits for the transmission/diffusion of electrolyte and surface redox reactions. As a result, they exhibit good supercapacitor performance in both acid (H2SO4) and alkaline (KOH) electrolytes. As compared to RuO2 bulk structure and similar RuO2 counterpart reported in pseudocapacitors, the two hierarchical porous RuO2·xH2O frameworks have better energy storage capabilities, high-rate performance, and excellent cycling stability.Keywords: hard-template method; hollow spheres; honeycomb network; hydrous RuO2; supercapacitors;

•Five polymers have been synthesized and characterized.•Polymer 1 possesses a 2-fold interpenetrating three-dimensional framework.•The fluorescence properties of 1–5 are studied.•Magnetic properties of 5 are also investigated.Five new polymers based on 5-(pyridine-3-yl)pyrazole-3-carboxylic acid (H2ppca), namely, [Cd2(ppca)(bix)(SO4)]n (1), {[Cd(Hppca)2]·H2O}n (2), {[Mn(Hppca)2]·H2O}n (3), [Zn2(ppca)2]n (4) and [Cu(ppca)]n (5) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses and IR spectroscopy. Structural analyses reveal that polymer 1 possesses a 2-fold interpenetrating three-dimensional (3D) framework. Polymers 2 and 3 display 4-connected 2D frameworks, while polymer 4 features a (3,3)-connected topology with the Schläfli symbol (4·8·10). 5 exhibits a 2D structure with the Schläfli symbol (4·82). Furthermore, the fluorescence properties of the five polymers are also investigated in the solid state, showing the fluorescence signal changes in comparing with that of free ligand mbbz. Polymer 5 with square pyramid geometry (τCu1, 0.069) implies that there is strong antiferromagnetic interactions between two adjacent Cu1C and Cu1, and the magnetic interactions are mainly transferred by the bridging N,N-triazole ligands.Five polymers have been synthesized and characterized. Polymer 1 possesses a 2-fold interpenetrating three-dimensional framework. Polymers 2–5 exhibit the 2D structures. The fluorescence properties of 1–5 are studied. Magnetic properties of 5 are also investigated.

The monometallic Ru catalysts with the CeO2 without calcination and ZnSO4 as co-modifiers gave a cyclohexene yield of 58.5% at the optimum nominal CeO2/Ru molar ratio of 0.15. Moreover, this catalyst had a good stability. The chemisorbed (Zn(OH)2)3(ZnSO4)(H2O)3 salt on Ru surface, which was formed by the CeO2 reacting with ZnSO4, created the new Ru active sites suitable for the formation of cyclohexene and improved the selectivity to cyclohexene. In addition, the Zn2+ in the aqueous phase could form a stable complex with cyclohexene, stabilizing the cyclohexene in the liquid phase and improving the selectivity to cyclohexene. The calcination treatment of CeO2 was not beneficial for the enhancement of the selectivity to cyclohexene since it is difficult for the CeO2 calcinated to react with ZnSO4 to form the (Zn(OH)2)3(ZnSO4)(H2O)3 salt.Sketches of the roles of the chemisorbed (Zn(OH)2)3 (ZnSO4)(H2O)3 salt (a) the Zn2+ covering some of Ru active sites; (b) the chemisorbed (Zn(OH)2)3 (ZnSO4)(H2O)3 salt making the M Ru catalyst be surrounded by a firm stagnant water layer

Ru–La catalysts with different La/Ru molar ratios were prepared by co-precipitation. Characterizations revealed that the promoter La existed as La(OH)3 on the Ru surface. The La(OH)3 itself could not enhance the selectivity to cyclohexene of Ru catalyst. However, the La(OH)3 could react with ZnSO4 in slurry to form an insoluble (Zn(OH)2)3(ZnSO4)(H2O)3 salt. The chemisorbed (Zn(OH)2)3(ZnSO4)(H2O)3 salt on Ru surface played a key role in improving the selectivity to cyclohexene of Ru catalyst. Ru–La catalyst with the optimum La/Ru molar ratio of 0.14 gave a maximum cyclohexene yield of 59.5%. Besides, Ru–La(0.14) catalyst had a good reusability and an excellent stability.Graphical abstractHighlight► The La in the catalyst existed as La(OH)3 on the surface of Ru particles. ► The La(OH)3 could react with ZnSO4 to form an insoluble (Zn(OH)2)3(ZnSO4)(H2O)3 salt. ► The (Zn(OH)2)3(ZnSO4)(H2O)3 salt improved the selectivity to cyclohexene of Ru catalyst. ► Ru–La(0.14) catalyst gave a maximum cyclohexene yield of 59.5%.

AbstractRu-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promoted with Zn or Mn alone. The optimum Mn/Zn molar ratio was determined to be 0.3. With the addition of 0.5 g NaOH, the Ru-Mn-Zn-0.3 catalyst, which was reduced at 150 °C, afforded a cyclohexene selectivity of 81.1% at a benzene conversion of 60.2% at 5 min and a maximum cyclohexene yield of 59.9% at 20 min. Based on characterizations, the excellent performance of Ru-Mn-Zn catalyst was ascribed to the suitable pore structure, the appropriate reducibility and the homogenous chemical environment of the catalyst.