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A stable luminescent Cd-MOF, formulated as [Cd(L)

Metal–organic frameworks have shown promising applications as electrode materials for supercapacitors because of the high porosity and tunable structures, but their poor water stability and conductivity limit their capacitance and efficiency. To demonstrate how to overcome these drawbacks, three isostructural Ni–organic frameworks with [NiII2NiIII(μ3-OH)(COO)6] trinuclear building blocks are selected. Taking advantage of high-connected architectures, absence of open metal sites, and effective inner-cluster redox process, three Ni–organic frameworks all are stable in KOH electrolyte and exhibit a pseudo-capacitor behavior with high specific capacitances up to 394, 426, and 465 F g–1. The increasing porosity facilitates the diffusion of metal ions and electrons and thus increases their electrochemical performance. Furthermore, we demonstrate that the in situ fabrication of metal–organic frameworks with graphene oxide can effectively promote their supercapacitor performance. With a given 3% graphene oxide do...

NiO has an unusually high theoretical specific capacitance and possess relatively high electrical conductivity compared to other metal oxides. However, the reported specific capacitance of the NiO-based electrodes is far below the theoretical value up to now. In this paper, three porous NiO materials with different specific surface area were synthesized simply by calcining iso-structural Ni-based MOFs templates. The formation mechanism of NiO was discussed by taking into account the thermal behavior and intrinsic structural features of the Ni-MOFs. Taking advantages of the Ni-MOFs precursors, all prepared NiO compounds are mesoporous and their porosity can be tuned by the structure of MOFs. Specially, due to the high porosity, three NiO exhibited an improved electrochemical performance and the specific discharge capacitances are of 102, 105, and 116 F g−1 at the current density of 1 A g−1, respectively. The specific capacitance of 1-NiO-450 is approximately 93.2% of its maximum value after 3000 cycles, which obviously superior to most of the previously reported NiO electrode materials and suggests their promising applications in supercapacitors.

Background: Sexual reproduction of plants is likely to be related to climate in their distribution range. Therefore, the investigation of spatial pattern of reproductive traits might provide valuab...

Pillared-layer metal–organic frameworks show great promise for gas storage and separation because their pore size as well as functionality usually can be controlled and adjusted synergistically. By combining the common pyridine and carboxylate groups, we design herein a new 3D pillared-layer framework, [Co2(DBPT)(BPY)2(CO3)]n (SNNU-95). Dinuclear [Co2] motifs are connected by DBPT ligands to form a 2D layer, which is further bridged by BPY to obtain the 3D pillar-layered framework of SNNU-95. Remarkably, two un-coordinated pyridine groups of DBPT not only help stabilize the 2D layer through π⋯π stacking but also point into the 1D channels to create an ultramicroporous environment. Taking advantage of the ultramicroporosity and pyridine Lewis basic sites, SNNU-95 shows not only extra high CO2 over CH4 and C2 hydrocarbons over CH4 selectivity, but also remarkable C2H2/CO2, C2H2/C2H4, and C2H4/CO2 separation under ambient conditions. This synergistic effect resulting from functional groups and pore size provides a promising route to design porous materials for the highest possible gas uptake and separation performance.

Four coordination polymers named [Co(L)0.5(bib)]n (1), Zn(H2L)(bib)]·2H2O}n (2), Cd(L)0.5(1,2-bimb)]n (3) and Zn(L)0.5(bib)]n (4) (H4L ​= ​5-(3,5-dicarboxybenzyloxy) isophthalic acid, bib ​= ​1,4-bis(1-imidazolyl)benzene, and 1,2-bimb ​= ​1,2-bis(1-imidazolylmethyl)benzene) were synthesized by solvothermal method and structurally characterized by means of single-crystal X-ray diffraction, infrared spectra and elemental analyses. Complex 1 crystallized in orthorhombic space group Pbcn had a 2-fold interpenetrated framework. Complex 2 showed a 4-fold interpenetrated framework. Complex 3 presented a 3-fold interpenetrated framework that crystallized in the triclinic system Pī space group. Complex 4 was a three-dimensional (3D) porous framework. Remarkably, the photocatalytic degradation experiments of complexes 1–4 on methylene blue (MB) indicated that these complexes 1–4 exhibited obvious degradation effect on MB. Moreover, the investigation of the luminescent properties of complexes 2–4 revealed that these complexes 2–4 could be served as a potential highly selective Fe3+ ion luminescent sensor. In addition, the magnetic analyses of complex 1 indicated that there was antiferromagnetic interaction between the Co (II) ions in complex 1.

The mimic of a (3,9)-connected xmz framework generates a novel highly connected Co-metal–organic framework (SNNU-80) constructed by trigonal prismatic [Co3(OH)(COO)6] building blocks and tripodal pyridyl-dicarboxylate ligands (BPYDB = 4,4′-(4,4′-bipyridine-2,6-diyl)-dibenzoic acid). Compared to the nonporous Co-pyridine-3,5-dicarboxylate xmz metal–organic framework (MOF), the extension of a triangular linker leads to a different geometrical distribution of ligands and thus a porous structure with the topology of 3,3,9T2 for SNNU-80. Four types of polyhedral cages coexist together, which produce permanent micro- and mesoporosity. Different from MCF-18 assembled by BPYDB with [Ni3(OH)(COO)6] showing drastic framework breathing, SNNU-80 is not flexible. As a result, SNNU-80 shows remarkable CO2 uptake capacity as well as high CO2 and C2 hydrocarbons over CH4 selectivity. Furthermore, the electrochemical measurements show that SNNU-80 is an idea electrode material for supercapacitors due to its highly connect...

A new column layered MOF with (3,6)-connected nets, namely [Co(pysa)(H2O)]n (YAU-7), was synthesized by using Co(NO3)2·6H2O and organic ligand 2-(pyrid-4′-yl)-benzimidazole-5-carboxylic acid (H2pysa) as flexible linkers. Single-crystal X-ray diffraction evidences the 3D YAU-7 MOF with (3,6)-connected nodes, a binuclear cluster [Co2(COO)2] structure and 1D tunnel feature. The weak interactions of π---π stacking enhances chemical stability of YAU-7 3D structure. Interestingly, the YAU-7 presents high chemical/thermodynamic stability, superior adsorption performance for CO2, CH4, C2H2 and C2H4, and high IAST selectivities for mixed gas systems of C2H2/CO2, C2H4/CO2, and CH4/CO2 (50/50). In contrast, YAU-7 exhibits higher uptake of CO2 (55.70 ​cm3 ​g−1) compared with CH4, C2H2, and C2H4 (27.39, 23.36, and 9.04 ​cm3 ​g−1) at 273 ​K. YAU-7 takes separation values for C2H2/CO2, C2H4/CO2, and CH4/CO2 mixture (37.6, 22.7, and 31.2) significantly higher than the C2H2/C2H4, C2H2/CH4, C2H2/CO2, C2H4/CH4 mixture gas (1.30, 1.83, 1.67). The YAU-7 MOF is a promising material for CO2 separation under ambient conditions.

Metal-organic frameworks with open active sites and appropriate pore size show great application promises in gas storage and separation due to their structural characteristics and functionality can be adjusted and controlled. Based on a benzimidazole and carboxylate decorated new MOF, [Cd(PCA)2]n, (YAU-1, HPCA=(2-(pyrid-4′-yl)-benzimidazole-5- carboxylic acid) has been gained under solvent-thermal conditions. Each dinuclear [Cd2] unit are linked through PCA− ligands to obtain a 2D layer structure, and the 2D structure is further connected by PCA− ligands to form the 3D framework of YAU-1. Remarkably, the un-coordinated benzimidazole and pyridine groups of PCA− ligand not only provide the 1D channels with exposed N atoms to create a mesoporous environment but also stabilizes 3D framework by π⋯π stacking. Taking advantage of these structural characteristics, YAU-1 shows different adsorption capacity for CO2, C2H2, C2H4 and CH4, and remarkable separation effect of C2H2/CH4, C2H4/CH4 and CO2/CH4. The research on the configuration-effect relationship of YAU-1 provides a promising methods to design and construction materials with high gas uptake and separation performance.

Two three-dimensional coordination polymers (CPs), namely [Cd(bpydb)- (H2bpydb)]n·0.5nH2O (1), and [Cu2(bpydb)2]n (2) (2,6-di-p-carboxyphenyl-4,4’- bipyridine1 = H2bpydb), containing a novel double-helical chains, which have been solvothermal synthesized, characterized, and structure determination. CPs 1-2 reveal the new (3,5)-net and (3,6)-net alb topology, respectively. The fluorescence properties of CPs 1-2 were investigated, and magnetic susceptibility measurements indicate that compound 1 has dominating antiferromagnetic couplings between metal ions.

Three novel coordination polymers, namely, [Cd(2-Hstp)(1,4-bbi)(H 2 O) 2 ]·3H 2 O ( 1 ), [Cd 1.5 (2-stp)(1,4-bbi)(H 2 O) 2 ]·H 2 O ( 2 ) and [Zn 2 (2-stp)( μ 2 -OH)(1,4-bbi) 1.5 (H 2 O)]·6H 2 O ( 3 ) (2-H 3 stp is equal to 2-sulfoterephthalate and 1,4-bisbenzimidazole is equal to 1,4-bbi), have been synthesized by hydrothermal reaction. The structural analyses show that 1 and 2 possess different structural features despite the same raw materials, which are 1D chain structure featuring 6-member-water H-bonds cluster and 3D bbi-pillared wavy-like layer framework, respectively. As changing the metal ion to zinc ion, 3 exhibits 3D stp-pillared layer architecture, which discovers the effect of the central metal ions on the formation of metal–organic frameworks. The fluorescence studies show that the emissions of the coordination polymers are attributed to the ligand π–π * transition, which means they could be potential fluorescence materials.

Hydrothermal reactions of manganese (II)/cadmium(II) salts with 1,2,4-trimellitic acid (H3tma) and 2,2′:6′,2-terpyridine (tpy) result in two novel complexes formulated with [M(Htma)(tpy)]·H2O (M = Mn(1) and Cd(2)). X-ray diffraction structural analyses of two complexes reveal they are isomorphic except for the different center metal ions and crystallize in the monoclinic crystal system of P(2)/n space group. The metal ion lies in a six-coordinated distorted octahedral environment coordinated with three Htma2− anions and one tpy ligand. There is an infinite two-dimensional rhombic network based on the metallic dimmers and Htma2− anions with the tpy ligands in void. Furthermore, the tpy ligands from the adjacent network weakly interact each other by π⋯π packing interactions into 3D supramolecular structure. The fluorescence properties could be assigned to the π – π* transition of organic ligands.

During the formation of magnesium-organic frameworks, the coordination sphere of magnesium tends to be partially occupied by O-containing solvent molecules such as amides, which will dramatically decrease the symmetry of Mg-organic frameworks and thus lead to low stability. It is noted that up to now, most reported Mg-metal–organic frameworks (MOFs) (>80%) crystallize in the space groups whose symmetry is lower than that of a tetragonal system. In this work, we demonstrate that acetate (Ac) may act as modulator to eliminate the influence of amide solvent and improve the symmetry of Mg-organic frameworks. Two novel Mg-MOFs, namely, {[(CH3)NH3]4[Mg3(BTB)8/3(Ac)2(H2O)]}n (SNNU-35, H3BTB = 4′,4′′,4′′′-benzene-1,3,5-tribenzoic acid) and {[(CH3)2NH2][Mg2(FDA)2(Ac)]}n (SNNU-36, H2FDA = 2,5-furandicarboxylic acid) were successfully designed, which crystallize in rhombohedral R-3 and tetragonal I4/mmm space groups, respectively. Four independent BTB ligands link three unique Mg cations and generate superlarge [Mg2...

A novel 3D Cd(ii) coordination polymer {[Cd(ddpa)(2,2'-bpy)]·H

Two copper coordination polymers (CPs) [Cu(1,2-BIYB)2(AQ-2,6-DA)]n·nH2O (1) and [Cu(1,4-BIYB)2(AQ-2,7-DA)]n·3nH2O (2) were obtained by reactions of pentahydrate copper sulfate with corresponding sulfonate and imidazole ligand under hydrothermal conditions, respectively [Na2AQ-2,7-DA = anthraquinone-2,7-disulfonic acid disodium salt, Na2AQ-2,6-DA = anthraquinone-2,6-disulfonic acid disodium salt, 1,4-BIYB = 1,4-bis(imidazol-1-ylmethyl)benzene, 1,2-BIYB = 1,2-bis(imidazol-1-ylmethyl)benzene]. CPs 1 and 2 show different structures: CP 1 has a 2D architecture, which is further extended into a 3D supramolecular structure through hydrogen bonding interactions, whereas CP 2 has a 1D architecture, which generates a 3D supramolecular structure via hydrogen bonding and strong π···π interaction. Notably, CPs 1 and 2 feature rare examples of CPs based visible-light-driven photocatalysts and reveal good stability toward photocatalysis.

Three new CdII coordination polymers, namely, {[Cd2 (L) (1, 2-bix)2(H2O)2]⋅2H2O}n(1), [Cd2 (L) (1, 3-bix)2]n (2), and {[Cd (H2L) (1, 4-bix) (H2O)2]⋅2H2O}n (3) [H4L = terphenyl-2, 2′, 4, 4′-tetracarboxylic acid, 1, n-bix = 1, n-bis(imidazol-l-ylmethyl) benzene (n = 2, 3, 4)], have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR, thermogravimetric analysis, and fluorescent analysis. Complex 1 is a 2D wavelike network structure incorporating the dinuclear Cd2 (1, 2-bix)2 units, whereas complex 2 possesses a 2D stair-like network structure consisting of the dinuclear Cd2O2 units. Complex 3 features a 2D puckered network constructed by 1D [Cd (H2L)]n and 1D [Cd (1, 4-bix)]n chains. The results show that the structural diversity of the polymers is mainly attributed to the usage of diverse ancillary bis (imidazol-1-ylmethyl)-benzene isomers ligands. The thermal stabilities and photoluminescence behaviors were also investigated.

The combination of 1,4-bis(imidazol-1-ylmethyl)benzene (BIYB) and anthraquinone-2,7-disulfonic acid (H2AQDA) ligands leads to a copper coordination polymer, namely, {[Cu(BIYB)2(AQDA)]·H2O}n (1). The cis-BIYB ligands link one unique Cu(II) atoms to give 1D double chains, but trans-BIYB connects the other Cu(II) centers to generate 2D (4,4)-layers. Each H2AQDA ligand acts as a μ2-bridging linking the double chains and (4,4)-layers to generate the 3D framework of 1. Cu(1) and Cu(2) can be viewed as 6- and 4-connected nodes, which lead to a (4,6)-connected self-penetrated network. Notably, complex 1 represents the rare example of coordination polymer-based visible-light-driven photocatalyst, and shows good degradation efficiency of organic dye.

Two three-dimensional (3D) lanthanide coordination polymers (CPs) of the general formula [Ln2(PDOA)3(H2O)]n·2nH2O [Ln = Gd (1), Tb (2)] were synthesized by solvothermal reactions of the corresponding rare-earth chloride and pyrazine-2,3-dicarboxylic acid (H2PDOA). The CPs were structurally characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetry, and elemental analysis. CPs 1 and 2 are isostructural and crystallize in the monoclinic space group P21/c. The frameworks are constructed from dinuclear lanthanide building blocks in which the PDOA2– ions adopt three coordination modes, μ3-kO;kO;kN,O, μ4-kN,O;kO;kO;kO,O, and μ5-kN,O;kO;kO;kO,O;kO, respectively. The Tb3+ polymer of 2 exhibits characteristic photoluminescence in the visible region. The magnetic properties of CP 1 were investigated by measuring the magnetic susceptibilities in the temperature range 1.8–300 K.

Spatial and structural characteristics of plant communities in the steppe ecosystems of the Baikal region, Russian Federation have been researched in connection with climate change and grazing. The present study, based on a total of 15 typical steppe sampling plots, investigated above-ground biomass (AGB), below-ground biomass (BGB), total biomass (TB) and root:shoot ratios (R:S) and their relationships with climatic factors and grazing. All biomass components varied widely depending on the climatic parameters and the degree of grazing affected transformation. A strong negative correlation between mean annual temperature (MAT) and total plant biomass was revealed for all study area. Mean annual precipitation (MAP) significantly affected communities productivity increasing only in the south of the region. Due to the large and mountainous territory, the influence of latitude and elevation (mountain) factors on the components of the biomass were studied. Although all studied plant steppe communities were transformed by uncontrolled grazing, their productivity is significantly reduced only at plots with maximum digression. Vegetation shift is an indicator of climate change, as well as providing a diagnostic tool to build predictive models. Based on the complex index of effective precipitation, it was revealed that at the end of last century in the steppes of the Baikal region the structural and production processes will be affected by an arid climate trend.

Vegetation characteristics of pastoralist households' pastures at different economic levels were quantified to compare the grassland conditions in Sunite Right Banner, Inner Mongolia, China in 2011 and 2012. The results showed that the heights of Stipa klemenzis and Cleistogenes songorica were similar among economic treatments. And the height of Allium polyrhizm had no significant differences between high-economic-level (HEL) and low-economic-level (LEL) treatments. There were no significant difference among treatments in the canopy cover of C. songorica. The densities of dominant species (S. klemenzis, C. songorica and A. polyrhizm) were significantly similar among treatments. Aboveground community biomass in reference area (CK) was higher than that in other three treatments in 2011, but their biomass showed no significant difference among three economic treatments; for 2012, biomass in HEL was higher than low-economic-level treatment (LEL), while the biomass in middle-economic-level treatment (MEL) and CK was similar to that in HEL and LEL, respectively. Aboveground biomass of S. klemenzis and C. songorica was similar among treatments in both 2011 and 2012. Biomass of A. polyrhizum had no significant difference between HEL and MEL. Households of LEL had rented out excess lands and those of HEL had leased their available lands thus resulting uniform utilization and convergence of pastoralist households' pastures across all economic levels.

To investigate the responses of alfalfa root-/ soil-associated arbuscular mycorrhizal (AM) fungal communities to phosphorus (P) addition, we examined the intraradical and extraradical mycorrhizal communities in an alfalfa (Medicago sativa) field being fertilized with four levels of P for 9 years. We found that AM fungal colonization declined significantly at the highest P level and was negatively related to soil available phosphorus, suggesting a decreased reliance on AM fungi at this high P level. A total of 22 operational taxonomic units (OTUs) from three families were detected in roots and 25 in soil. Both AM fungal OTU richness and diversity in soil were higher than that in roots. The AM fungal diversity in roots declined significantly when P was the highest. The indicator species in roots increased in relative abundance in the P1 treatment (75 kg P2O5 ha−1 a−1). Although P addition had no significant effect on OTU richness or AM fungal community composition in soil, we found that pH and soil organic matter structured roots and soil mycorrhizal communities, respectively. In conclusion, P addition affected root and soil AM fungal communities differently. Further research is needed to determine how individual AM fungal species may respond to P fertilization, and how this may impact plant productivity.

Two new Cd(II) coordination polymers, [Cd2(btc)(dpe)1.5(H2O)]n (1) and [Cd2(btc)(bpp)(H2O)]n (2), were prepared by the hydrothermal reaction of cadmium nitrate with H4btc (H4btc = biphenyl-2,2′,4,4′-tetracarboxylic acid) in the presence of 1,2-di(4-pyridyl)ethylene (dpe) and = 1,2-bis(4-pyridyl)propane (bpp), respectively, structurally characterized by single-crystal X-ray diffraction, and further characterized by elemental analysis, IR spectroscopy, and thermogravimetric analysis. In 1, btc4− connect six Cd2+ ions, forming a 3-D (3,3,6)-connected [Cd2(btc)] net, and further connected by 1-D [Cd(dpe)]n chains to construct the final (4,5,6)-connected (42.52.65.7)(43.62.7)(45.53.64.72.8) net. In 2, a 3-D [Cd2(btc)] net is also constructed from btc4− connecting six Cd2+ ions, giving a 3-D (3,4,7)-connected network. The overall structure of 2 can be regarded as a (4,4,6)-connected (45.64) (42.5.62.8) (43.54.67.7) framework with bpp linking adjacent Cd ions. Structural comparisons show that the secondary auxil...

Two new coordination polymers, [Cd(bct)(H2O)]·(H2O) (1) and [Zn(bct)(bip)]·2(H2O) (2) (H2bct = 3,5-bis(4′-carboxy-phenyl)-1,2,4-triazole, bip = 1,4-bis(imidazol-1-ylmethyl)benzene), have been synthesized. Their structures have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectroscopy, and thermogravimetric analysis. Compound 1 is a two-dimensional structure with double-layered network, where bct ligands adopt a μ 4 -k 1,k 1,k 1,k 1 bridging mode linking four five-coordinate Cd ions. Compound 2 exhibits a three-dimensional framework consisting of double-layered helical chains with the bct and bip adopting μ 3 -k 1,k 1,k 1 and μ 2 -k 1,k 1 bridging mode, respectively. Complexes 1 and 2 exhibit intense emissions at 399 and 441 nm, respectively.

Solvothermal reactions of 2-phenyl-4-quinolinecarboxylic acid (Hpqba) with CdII, CoII, ZnII and/or 4,4′-bipyridyl (4,4′-bipy), 1,4-bis(imidazol-1-ylmethyl)benzene (biyb), 2,2′-bipyridyl (2,2′-bipy) afford three new coordination compounds of stoichiometries [Cd(pqba)2(4,4′-bipy)] (1), [Zn(pqba)2biyb] (2), and [Co3(pqba)6-(2,2′-bipy)2] (3). Compounds 1–3 were characterized by elements analysis, IR spectroscopy, thermogravimetry, and single-crystal X-ray diffraction study. Compound 1 has a two-dimensional structure, whereas compound 2 consists of a one-dimensional (1D) network, which is further expanded by π···π stacking interactions to form a 3D supramolecular structure. Complex 3 also exhibits a 3D supramolecular structure completely based on π···π stacking interactions. The pqba ligands adopt μ1-k1,k1, μ1-k1, μ2-k1,k1, and μ2-k1,k2 coordination modes for compounds 1, 2, and 3. The fluorescence properties were examined on compounds 1 and 2 in the solid state at room temperature. Magnetic susceptibility measurements indicate that in complex 3 antiferromagnetic coupling between adjacent CoII ions exist.

This study conducted experiments using Stipa grandis, the dominant species of the typical steppe in Inner Mongolia. The research explored the different effects of mowing and grazing on organic carbon, total nitrogen, available nitrogen, total phosphorus and available phosphorus in rhizosphere and bulk soil. The results showed that: Both mowing and grazing inhibited assemble and storage capacity of rhizosphere, and decreased the organic carbon, total nitrogen, and available nitrogen contents in rhizosphere soil. The rhizosphere effect on total phosphorus in soil was found to be insignificant because of its high immobility. Available phosphorus in soil was distributed heterogeneously. Available soil phosphorus under mowing and grazing changed but the difference was not significant between rhizosphere and bulk soil. Grazing drastically reduced the number of soil microbes. The availability of soil nutrients was significantly correlated with soil microbial numbers. The status of soil nutrients could be more closely aligned with the change in bacteria and fungi. Grazing brought about greater soil nutrient loss and soil microbe loss than did mowing.

Two novel d10 metal coordination polymers [Cd2(Hmna)4]n (1), [Zn2(ddca)2 (dpe)]n·nH2O (2) (H2mna = 6-mercaptonicotinic acid, H2ddca = 6, 6'-dithiodinicotinic acid, dpe = 1, 2-bis(4-pyridyl)ethylene), were hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Compound 1 is a cyclic double chain structure containing 16-number and 32-number circles with (Hmna)– ligands as bridges, in which the starting H2ddca reagent was unprecedentedly converted into H2mna ligands via in situ cleavage of S–S bonds during the course of hydrothermal treatment. In compound 2, two five-coordinate zinc centers are connected with carboxylate groups of H2ddca ligands to give a binuclear [Zn2(CO2)4] unit, which are linked by dpe ligands to form a 2D network structure. It is worth noting that compound 2 displays a twofold 2D+2D parallel interpenetration framework containing a polyrotaxane-like motif. In addition, the thermal stablities and photoluminescence properties of compounds 1 and 2 were also studied.

In this article, [Ag8(btc)2(2,2′-bpy)2] n (1) and [Ag4(btc)(phen)2] n (2) (H4btc = biphenyl-2,2′,4,4′-tetracarboxylic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectra, thermogravimetric analyses, and single-crystal X-ray diffraction. Complex 1 shows a 3-D framework containing a 2-D bilayer network constructed from (btc)4− with Ag (I), whereas 2 features a 2-D supramolecular bilayer network. The differences of the two complexes demonstrate that nitrogen-containing chelating ligands have a significant effect on the formation and structure of the resulting complexes. Electrochemistry properties of 1 were also studied.

A new 3D metal-organic framework {[Ag4(btc)(bix)2]·H2O}n (1) [H4btc = biphenyl-2, 2′,4, 4′-tetracarboxylic acid, bix = 1, 4-bis(imidazol-1-ylmethyl)benzene] was synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, infrared (IR) spectroscopy, thermal gravimetric analysis (TGA), and luminescence studies. The most remarkable structural feature of 1 is that the 1D chain and 2D network interpenetrated structures are further linked by parallel aligned 1D AgI chains to generate 3D metal-organic framework.

Self-assembly of anthraquinone-2,6-disulfonic acid disodium salt (Na2a-2,6-dad) and AgNO3 under hydrothermal conditions resulted in an unprecedented coordination complex, which was characterized by single-crystal X-ray analyses, elemental analyses, IR spectra, TG analyses, and fluorescence investigations. Complex 1 is a 3-D coordination polymer, where a-2,6-dad and Ag–Ag bonds play vital roles. Two sulfonate groups of a-2,6-dad are μ 4- and μ 5-bridges. The unique packing environments of the Ag ions and Ag–Ag bonds lead to 1-D chains consisting of eight- and four-membered rings for Ag1 and Ag1, Ag2 and Ag2 connection, respectively.

Coordination polymers of CuII and NiII with 3-pyridin-3-yl-benzoic acid (3,3-Hpybz), {[Cu(3,3-pybz)2(CH3OH)]·(DMF)} n (1) and {[Ni(3,3-pybz)2(H2O)] · (H2O)} n (2), were synthesized and characterized by single-crystal X-ray diffraction, thermogravimetric analyses, elemental analysis, and IR spectroscopy. In 1, CuII ions are linked by paired 3,3-pybz ligands to generate an infinite 1-D double-strand chain. However, NiII ions in 2 are linked by the 3,3-pybz to form a 2-D corrugated network with a simple (4,4) topology; these 2-D layers are further enlarged to form the final 3-D supramolecular edifice via strong aromatic π–π stacking interactions and O–H ··· O hydrogen bonds. Magnetic properties of 1 and 2 have also been investigated.

Two new coordination polymers, {[Cd2(btc)(2,2′-bpy)2]·H2O}n (1) and [Zn2(btc)(2,2′-bpy)(H2O)]n (2) (H4btc = biphenyl-2,2′,4,4′-tetracarboxylic acid, 2,2′-bpy = 2,2′-bipyridine), were synthesized hydrothermally under similar conditions and characterized by elemental analysis, IR spectra, TGA, and single-crystal X-ray diffraction analysis. In complexes 1 and 2, the (btc)4– ligand acts as connectors to link metal ions to give a 2D bilayer network of 1 and a 3D metal-organic framework of 2, respectively. The differences in the structures are induced by diverging coordination modes of the (btc)4– ligand, which can be attributed to the difference metal ions in sizes. The results indicate that metal ions have significant effects on the formation and structures of the final complexes. Additionally, the fluorescent properties of the two complexes were also studied in the solid state at room temperature.

The reactions of anthraquinone-2,6-disulfonic acid disodium salt (Na2a-2,6-dad) with CuII, MnII, and ZnII with 1,10-phenanthroline (phen) or 2,2′-dipyridyl (bipy) under hydrothermal conditions formed two or three-dimensional supramolecules of stoichiometries [Cu(a-2,6-dad)(phen)(H2O)3](H2O)4 (1), [Mn(a-2,6-dad)(bipy)2(H2O)](H2O)2 (2), and [Zn(a-2,6-dad)(bipy)2(H2O)](H2O)2 (3), which were synthesized and characterized. The arrangement around each metal atom is distorted octahedral. The ligands in all the compounds are engaged in intermolecular hydrogen bonding leading to the formation of hydrogen-bonded networks, the compounds show novel π–π stacking interactions. Photoluminescence measurements indicate that the compound [Zn(a-2,6-dad)(bipy)2(H2O)](H2O)2 (3) shows strong blue luminescence in the solid state at room temperature.