•Two novel triazole-Cu(II) coordination polymers have been isolated under solvo-thermal conditions.•Variable-temperature magnetic susceptibility of 1–2 indicate weak anti-ferromagnetic interactions.•2 can effectively capture Cr2O72− in the water solutions and selectively capturing Congo Red in the methanol solutions.In this work a flexible multi-dentate 1-(4-aminobenzyl)-1,2,4-triazole (abtz) ligand has been employed, two novel triazole-Cu(II) coordination polymers {[Cu(abtz)2(Br)2]·(H2O)2}n (1) and {[Cu(abtz)2]·(SiF6)·(H2O)2}n (2) have been isolated under solvo-thermal conditions. 1 is a 2D neutral CuII coordination polymer while 2 is 2D cation micro-porous CuII coordination polymer with the channel dimensionalities of 11.852(1) Å × 11.852(1) Å (metal-metal distances). Variable-temperature magnetic susceptibility data of 1 and 2 have been recorded in the 2–300 K temperature range indicating weak anti-ferromagnetic interactions. Further absorption properties of anion pollutants for 2 also have been investigated. 2 presents the novel example of cationic triazole-copper(II) coordination framework for effectively capturing anion pollutants Cr2O72− in the water solutions and selectively capturing Congo Red in the methanol solutions.

In this work two positional-isomeric oxadiazol-pyridine ligands 3-(5-methyl-1,3,4-oxadiazol-2-yl)pyridine (L1) and 4-(5-methyl-1,3,4-oxadiazol-2-yl)pyridine (L2) have been designed and synthesized. A series of novel coordination polymers, namely [Cd2(μ2-L1)2(μ2-NCS)4]n (1), {[Cd(L1)(μ2-dca)2(H2O)]·H2O}n (2), {[Cu(μ2-L1)2(NCS)2]·0.5H2O}n (3), {[Ag2(μ2-L1)(μ3-L1)2]·2PF6}n (4), {[Ag3(μ2-L1)4(μ2-CF3SO3)(CF3SO3)]·CF3SO3} (5), {[Cd(L2)2(μ2-NCS)2]}n (6), [Ag(μ2-L2)(μ2-CF3SO3)]n (7) and {[Ag(μ2-L2)]·BF4}n (8) have been isolated. Both 1 and 2 are 2D CdII coordination polymers containing infinite {Cd–NCS–Cd} chains (for 1) or infinite {Cd–dca–Cd} layers (for 2), respectively. 3 is a 2D CuII coordination polymer, in which central metal ions are bridged via a bidentate bridging L1 ligand. While when different AgI salts were introduced into the reaction system, 1D AgI coordination polymers 4 and 5 with diverse coordination modes can be isolated. Furthermore, when the isomeric oxadiazol-pyridine L2 is used to replace L1 in the reaction system, 6–8 can be isolated. 6 is a 2D CdII coordination polymer containing {Cd–NCS–Cd} layers. 7 is a 2D neutral AgI coordination polymer while 8 is a 2D cationic AgI coordination polymer. Variable temperature magnetic susceptibility measurements (2–300 K) reveal anti-ferromagnetic interactions between central copper(II) ions for 3. Solid-state luminescent properties of 1, 2 and 4–8 have been investigated indicating strong fluorescent emissions. Additionally, luminescent measurements illustrate that complex 8 exhibits highly sensitive luminescence sensing for Cr2O72− ions in aqueous solutions with high quenching efficiency Ksv = 2.08 × 104 L mol−1 and low detection limit (0.19 μM (S/N = 3)). 8 also represents the first report of a coordination polymer based on oxadiazol-pyridine derivatives with a luminescence response to Cr2O72− anion pollutants in aqueous solutions.

•A cluster-based nano-porous Terbium luminescent metal-organic framework {[Tb(L)(H2O)(DMF)]·DMF}n (1) has been isolated.•Luminescence explorations suggested that 1 exhibits highly selective and real-time sensitive sensing for benzaldehyde.•1 also exhibits shows excellent selectivity, fast detection time, high sensitivity and visual detection for Nitrite.•1 represents a unique multi-functional 3D cluster-based Nano-porous Terbium metal organic material.In this work one rigid asymmetrical tricarboxylate ligand p-terphenyl-3,4″,5-tricarboxylic acid (H3L) ligand has been synthesized, one unique nano-porous Terbium luminescent metal-organic framework {[Tb(L)(H2O) (DMF)]·DMF}n (1) has been prepared using solvo-thermal techniques. Structural analysis demonstrated that these di-nuclear Tb2O2 clusters are bridged via rigid ter-phenyl backbones of L3− generating one unique three-dimensional(3D) cluster-based nano-porous framework of 1. In 1 nano-porous channels with dimensionality of 9.788(1) Å × 19.209(3) Å can be found along the crystallographic a direction. According to a PLATON calculation, there exists approximately 33.7% of the crystal volume (6286.8 Å3 potential solvent areas) accessible to guest molecules. Powder X-ray diffraction (PXRD) determination also confirms pure phases of 1. Photo-Luminescent experiments suggested that 1 shows real-time sensitive sensing for benzaldehyde. Addition of only 1 μl benzaldehyde to ethanol emulsion of 1, the resulting emission intensity was attenuated by approximately 52.07%. It is also noted that the fluorescent intensity of 1 can be efficiently resumed through the fast and simple technique of washing the benzaldehyde-1 sample by water. Meanwhile 1 also showed high selectivity, fast detection time (<1 min), excellent sensitivity (detection limit, 0.54 μM) and visual detection for nitrite over other anions in aqueous solutions. The quenching efficiency of 1 by nitrite is not only linearly correlated with nitrite concentration in the wide range of 3–1000 μM, but also linearly correlated with reaction time, which is scarcely reported in the previous photo-luminescent sensors for nitrite. Moreover, 1 can selectively adsorb organic dye Congo Red (CR) possessing a high absorption amount of 636.94 mg/g in water solutions. Time dependence for CR adsorption on 1 can be well depicted by using the pseudo-second-order kinetic model, which is consistent with chemisorption mechanism. Therefore 1 also represents a unique multi-functional 3D cluster-based nano-porous Terbium metal organic material as real-time detection of benzaldehyde, visual chemosensor for nitrite and high amount absorption of CR.Download high-res image (357KB)Download full-size image

In this work a rigid asymmetrical tricarboxylate ligand p-terphenyl-3,4″,5-tricarboxylic acid (H3L) has been employed, and a unique heterometallic alkaline earth–lanthanide microporous luminescent metal–organic framework (MOF) {[Ba3La0.5(μ3-L)2.5(H2O)3(DMF)]·(3DMF)}n (1·3DMF) (DMF = dimethylformamide) has been isolated under solvothermal conditions. Single-crystal X-ray structural analysis demonstrates that 2D inorganic Ba–O–La connectivity can be observed in 1, which are further bridged via rigid terphenyl backbones of L3–, forming a unique I2O1-type microporous luminescent framework. A 1D microporous channel with dimensionality of 9.151(3) Å × 10.098(1) Å can be observed along the crystallographic a axis. PXRD patterns have been investigated indicating pure phases of 1. The luminescence explorations demonstrated that 1 exhibits highly selective and sensitive sensing for Al3+ over other cations with high quenching efficiency Ksv value of 1.445 × 104 L·mol–1 and low detection limit (1.11 μM (S/N = 3)). Meanwhile 1 also exhibits highly selective and sensitive sensing for MnO4– over other anions with quenching efficiency Ksv = 7.73 × 103 L·mol–1 and low detection limit (0.28 μM (S/N = 3)). It is noted that, when different concentrations of MnO4– solutions (0.5 to 100 μM) were dropped into the suspension of 1, the bright blue luminescence of the suspension observed under UV light can gradually change into pink color, indicating visually luminescent sensing, which makes the detection process of MnO4– more convenient in practical. The result also reveals that 1 represents the first example of bifunctional heterometallic alkaline earth-lanthanide MOF-based luminescent probes for selectively detecting Al3+ and MnO4– in the water solutions.

In this work a flexible multi-dentate 1-(4-aminobenzyl)-1,2,4-triazole (abtz) ligand has been employed, a unique cationic triazole–Ag(I) metal–organic nanotube {[Ag(μ3-abtz)]·(NO3)·(0.125H2O)}n (MONT-1) has been isolated under solvo-thermal conditions. The abtz ligands adopt tri-dentate coordination modes via triazole nitrogen atoms and aromatic amino nitrogen atoms, which bridge neighboring AgI centers in a syn conformation, leading to MONT formation. PXRD patterns have been investigated indicating pure phases of MONT-1. Solid-state luminescence properties indicate strong fluorescent emissions of MONT-1 at room temperature. Further, interestingly MONT-1 exhibits visually highly selective and sensitive luminescence sensing for Cr2O72− ions in aqueous solutions with high quenching efficiency Ksv = 1.97 × 104 L mol−1 and low detection limit (0.19 μM (S/N = 3)), which make it a promising candidate for visually sensing Cr2O72− anion pollutants in practice. On the other hand, the absorption of environmental pollutants by MONT-1 has also been investigated. MONT-1 has a high absorption capacity for Cr2O72− (211.8 mg g−1), and these absorbed Cr2O72− anion pollutants can be gradually released in the presence of nitrate. Additionally MONT-1 also can selectively adsorb Congo Red (CR) dye molecules in aqueous solutions with a high absorption capacity of 823.3 mg g−1. Therefore MONT-1 can be used a unique multi-functional 1D nano-tubular metal–organic material in sensitive detection and effective adsorption/removal of these environment pollutants in industrial waste water solutions.

In this work two new multi-dentate 1,2,4-triazole derivate ligands 4-(4-methyl-2-pyridine)-1,2,4-triazole (L1), 4-(5-methyl-3-pyridine)-1,2,4-triazole (L2) have been designed and synthesized. Three novel cluster-based cationic silver(I) coordination compounds with L1 and L2, namely [Ag2(H2O)4(L1)2](CF3CO2)2 (1), [Ag4(L1)6](BF4)4 (2) and {[Ag2(H2O)(L2)2]·(BF4)2}n (3) have been isolated. When L1 and different Ag(I) salts are used, the bi-nuclear Ag(I) cluster 1 and the tetra-nuclear Ag(I) cluster 2 can be isolated indicating anion induced structural diversity. Further when L2 is used, 3 can be isolated. 3 is a 2D clustered-based coordination compound based on bi-nuclear Ag(I) clusters. PXRD patterns and solid state luminescent properties of 1–3 have been investigated. Further anion exchange properties 2 and 3 also have been investigated. 2 and 3 present novel examples of triazole–silver(I) coordination compounds for effectively capturing the anion pollutants Cr2O72−, MnO4− in water solutions and Congo Red in methanol solutions through the anion exchange process.

In this work a new flexible multi-dentate 1-(4-aminobenzyl)-1,2,4-triazole (abtz) ligand has been designed and synthesized, and a series of two-dimensional (2D) triazole-functionalized metal–organic frameworks, namely {[Cd(abtz)2(H2O)2]·(ClO4)2·H2O}n (1), {[Cd(abtz)2(H2O)2]·(SiF6)}n (2), {[Cd(abtz)2(H2O)2]·(ClO4)1.64·(HSO4)0.36·1.36H2O}n (3), {[Cd(abtz)2(NCS)]·(ClO4)}n (4) and {[Ag2(μ2-abtz) (μ3-abtz)(ClO4)]·(ClO4)}n (5) have been isolated. Firstly, when abtz and corresponding cadmium(II) salts are employed, new rectangular-grid 2D coordination frameworks containing free ClO4− or SiF62− anions, {[Cd(abtz)2(H2O)2]·(ClO4)2·H2O}n (1) and{[Cd(abtz)2(H2O)2]·(SiF6)}n (2), can be isolated. Furthermore, in 1 weakly H-bonded ClO4− anions present within the voids can be partly exchanged by HSO4− anions to generate the anion exchanged crystalline product {[Cd(abtz)2(H2O)2]·(ClO4)1.64·(HSO4)0.36·1.36H2O}n (3) in single-crystal-to-single-crystal (SC–SC) manner. On the other hand, 1 can be used as a precursor to react with NH4NCS to obtain the 2D bilayer framework {[Cd(abtz)2(NCS)]·(ClO4)}n (4) under hydrothermal conditions. This also presents a novel example of structural transformation with bond rupture/formation from a mono-layer framework 1 to a 2D bi-layer framework 4. Furthermore, when AgClO4 is used to replace Cd(ClO4)2 in the reaction system, another 2D layer framework {[Ag2(μ2-abtz)(μ3-abtz) (ClO4)]·(ClO4)}n (5) with unique (2,4,5) connected topology can be isolated. The solid state luminescence properties and PXRD patterns of 1–5 have been investigated. Additionally, luminescence measurements illustrate that complexes 4 and 5 represent novel examples as luminescent probes of new sensing materials. 4 shows highly sensitive response to acetone and Fe3+. Besides, 5 is the first report of multidimensional polymers based on triazole derivatives with luminescent response to small biological molecules such as vitamin C in water solutions.

•Two novel 3D porous Copper(II) and Zinc(II) frameworks have been isolated.•1 presents a 3D Copper(II) framework with 4-connected 6383 dmp topology.•2 presents a 3D cluster-based framework with 6-connected α-Po-related (41263) topology.Used versatile multidentate benzene-based bis-triazole ligand 1,3-di-(1,2,4-triazole-4-yl)benzene (L), two novel 3D porous Copper(II) and Zinc(II) frameworks, namely {[Cu(μ2-L)2(SiF6)(H2O)]·0.5H2O}n (1) and {[Zn3(μ3-L)6](NO3)6}n (2), have been isolated under the hydrothermal conditions. The structural analysis reveals that 1 presents a 3D microporous Copper(II) framework with the novel 4-connected 6383 dmp topology containing infinite right- and left-handed Cu(μ2-L)2 helical chains. While 2 presents a 3D cluster-based nano-porous cationic host framework with 6-connected α-Po-related (41263) topology, in which trinuclear Zinc(II) clusters can be defined as basic nodes. The varied temperature magnetic susceptibility of 1 (from 300 to 2 K) and solid state luminescent property of 2 also have been investigated.Two novel 3D porous frameworks with 1,3-di-(1,2,4-triazole-4-yl)benzene have been isolated. 1 presents a 3D microporous Cu(II) framework with 4-connected 6383 dmp topology, while 2 presents a 3D cluster-based nano-porous framework with 6-connected α-Po-related topology.