Construction of (3,8)-connected three-dimensional cobalt(II) and copper(II) coordination polymers with 1,3-bis[(1,2,4-triazol-4-yl)methyl]benzene and benzene-1,3,5-tricarboxylate ligands.

Coordination polymers (CPs) have been widely studied because of their diverse and adjustable topologies and wide-ranging applications in luminescence, chemical sensors, magnetism, photocatalysis, gas adsorption and separation. In the present work, two coordination polymers, namely poly[(µ5-benzene-1,3,5-tricarboxylato-κ6O1:O1':O3:O3:O5,O5'){µ3-1,3-bis[(1,2,4-triazol-4-yl)methyl]benzene-κ3N:N':N''}di-µ3-hydroxido-dicobalt(II)], [Co2(C9H3O6)(OH)(C12H12N6)]n or [Co2(btc)(OH)(mtrb)]n, (1), and poly[[diaquabis(µ3-benzene-1,3,5-tricarboxylato-κ3O1:O3:O5)bis{µ3-1,3-bis[(1,2,4-triazol-4-yl)methyl]benzene-κ3N:N':N''}tetra-µ3-hydroxido-tetracopper(II)] monohydrate], {[Cu4(C9H3O6)2(OH)2(C12H12N6)2(H2O)2]·H2O}n or {[Cu4(btc)2(OH)2(mtrb)2(H2O)2]·H2O}n, (2), were synthesized by the hydrothermal method using 1,3-bis[(1,2,4-triazol-4-yl)methyl]benzene (mtrb) and benzene-1,3,5-tricarboxylate (btc3-). CP (1) exhibits a (3,8)-coordinated three-dimensional (3D) network of the 3,8T38 topological type, with a point symbol of {4,5,6}2{42·56·616·72·82}, based on the tetranuclear hydroxide cobalt(II) cluster [Co4(µ3-OH)2]. CP (2) shows a (3,8)-coordinated tfz-d topology, with a point symbol of {43}2{46·618·84}, based on the tetranuclear hydroxide copper(II) cluster [Cu4(µ3-OH)2]. The different (3,8)-coordinated 3D networks based on tetranuclear hydroxide-metal clusters of (1) and (2) are controlled by the different central metal ions [CoII for (1) and CuII for (2)]. The thermal stabilities and solid-state optical diffuse-reflection spectra were measured. The energy band gaps (Eg) obtained for (1) and (2) were 2.72 and 2.29 eV, respectively. CPs (1) and (2) exhibit good photocatalytic degradation of the organic dyes methylene blue (MB) and rhodamine B (RhB) under visible-light irradiation.

An unusual porous cationic metal-organic framework based on a tetranuclear hydroxyl-copper(ii) cluster for fast and highly efficient dichromate trapping through a single-crystal to single-crystal process.

An unusual porous cationic metal-organic framework based on a tetranuclear hydroxy-copper(ii) cluster displays fast and highly efficient dichromate trapping through a single-crystal to single-crystal process.

A new strategy to obtain tetranuclear cobalt(ii) metal-organic frameworks based on the [Co4(µ3-OH)2] cluster: synthesis, structures and properties.

Three metal-organic frameworks (MOFs) {[Co4(OH)2(adc)6(H2O)5][Co2(OH)(btrb)]2·8H2O}n (1), {[Co4(OH)2(btrb)(nip)3(H2O)3]·4H2O}n (2·4H2O) and {[Co4(OH)2(btrb)(btc)2(H2O)2]·9H2O}n (3·9H2O) (btrb = 1,4-bis(1,2,4-triazol-4-ylmethyl)benzene, H2adc = 1,3-adamantanedicarboxylic acid, H2nip = 5-nitroisophthalic acid and H3btc = 1,3,5-benzenetricarboxylic acid) were synthesized by a hydrothermal method. 1 shows an unusual (3,4)-connected 2D network with a point symbol of (4·62)2(42·62·82) based on [Co4(µ3-OH)2] and [Co2(µ3-OH)] units. 2 is a 6-connected pcu topology based on the [Co4(µ3-OH)2] unit. 3 is a rare (3,8)-connected 3D framework with a rare point symbol of (4·5·6)2(42·56·616·72·82) based on the [Co4(µ3-OH)2] unit. The magnetic measurements reveal that 1-3 exhibit antiferromagnetic interactions between the adjacent cobalt(ii) centers. 1-3 are good photocatalysts for the degradation of methylene blue (MB). The 1,2-position nitrogen atoms of the 4-substituted 1,2,4-triazole ligand act as strong σ-donators to form a quite stable coordination quadrangle with two metal ions. The btrb ligand containing two 4-substituted 1,2,4-triazole rings is favorable to form tetranuclear metal units. By the regulation of the multicarboxylate ligands, the connection number of [Co4(µ3-OH)2] clusters increases from 4 in 1 to 6 in 2 and then 8 in 3. This work presents a novel but effective method to design and regulate the connection number (4, 6 and 8 connected in this work) of MOFs with 4-substituted 1,2,4-triazole and rigid multicarboxylate ligands.

Berberine inhibits norepinephrine-induced apoptosis in neonatal rat cardiomyocytes via inhibiting ROS-TNF-α-caspase signaling pathway.

OBJECTIVE: To determine the effect of berberine (Ber) on norepinephrine (NE)-induced apoptosis in neonatal rat cardiomyocytes. METHODS: The cultured neonatal rat cardiomyocytes were treated with NE in the presence or absence of Ber. The activity of lactate dehydrogenase (LDH) in the culture medium was examined, and apoptosis of cardiomyocytes was assessed by Hoechst 33258, isothiocyanate (FITC)-conjugated annexin-V, and propidine iodide (PI) staining. In addition, the activities of caspases-2 and-3 were measured by a fluorescent assay kit. The level of secreted tumor necrosis factor α (TNF-α) and production of intracellular reactive oxygen species (ROS) were also determined. RESULTS: NE at a concentration of 50 µ mol/L induced an obvious increase in the activity of LDH in the culture medium (P<0.05), which was inhibited by coincubation with 0.5, 1.0, or 2.0 µ mol/L Ber (P<0.05). Ber also significantly attenuated NE-induced apoptosis in a dose-dependent manner (P<0.01). Moreover, Ber at a dose of 2 µ mol/L markedly decreased the ROS and TNF-α productions (P <0.05) and inhibited the activation of caspases-2 and -3 in cardiomyocytes exposed to NE (P<0.05)h. CONCLUSION: The present study suggested that Ber could reduce NE-induced apoptosis in neonatal rat cardiomyocytes through inhibiting the ROS-TNF-α-caspase signaling pathway.