Jie Ding

Novel coordination polymers of Zn(II) and Cd(II) tuned by different aromatic polycarboxylates: synthesis, structures and photocatalytic properties

Tuned by different aromatic polycarboxylates, six fascinating coordination polymers (CPs), namely, [Cd(pbmb)(p-bdc)]n (1), {[Zn3(pbmb)2(1,3,5-btc)2]·6H2O}n (2), {[Cd3(pbmb)3(1,3,5-btc)2(H2O)]·3H2O}n (3), {[Zn2(pbmb)(1,2,3-btc)(μ2-OH)]·H2O}n (4), [Cd(pbmb)(1,2,4,5-btec)0.5]n (5), and {[Cd(pbmb)(sdba)]·2H2O}n (6) (pbmb = 1,1′-(1,3-propane)bis-(2-methylbenzimidazole), p-H2bdc = 1,4-benzenedicarboxylic acid, 1,3,5-H3btc = 1,3,5-benzenetricarboxylic acid, 1,2,3-H3btc = 1,2,3 benzenetricarboxylic acid, 1,2,4,5-H4btec = 1,2,4,5-benzenetetracarboxylic acid, H2sdba = 4,4′-sulfonyldibenzoic acid), have been ideated and synthesized by hydrothermal reaction methods. Structural analyses reveal that complexes 1–3 feature three-dimensional (3D) structures (1: 4-connected 66 topology, 2: (3,4,6)-connected (65·7)(4·62)2(42·66·85·102) topology and 3: (2,3,4)-connected (65·8)2(63)2 topology), and the remaining CPs 4–6 exhibit 2D networks. The thermal stability and powder X-ray diffraction for 1–6 have been investigated as further properties. The optical band gaps are analyzed by diffuse-reflectance UV-vis spectra. Moreover, all of the materials manifest good photocatalytic activities for the degradation of methylene blue (MB) (1: 74%, 2: 41%, 3: 37%, 4: 76%, 5: 46%, 6: 75%, respectively) in water under the irradiation of a high-pressure mercury lamp.

Spectroscopic and crystallographic investigations of novel BODIPY-derived metal-organic frameworks.

To explore new 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-derived metal-organic frameworks (MOFs), we employed 2,6-dicarboxyl-1,3,5,7-tetramethyl-8-phenyl-4,4-difluoroboradiazaindacene (H2L) as a ligand to successfully synthesize five coordination polymers, namely, {[Zn2(L)2(bpp)]·2H2O·2EtOH}n (1), {[Cd2(L)2(bpp)]·2H2O·EtOH}n (2), {[Cd2(L)(bpe)3(NO3)2]·2H2O·DMF·EtOH}n (3), {[Cd(L)(bpe)0.5(DMF)(H2O)]}n (4), and {[Cd(L)(bpe)0.5]·1.5H2O·DMF}n (5) (bpp = 1,3-bi(4-pyridyl)propane, bpe = 1,2-bi(4-pyridyl)ethane). Except for two 2D-layer coordination polymers 3 and 4, the rest samples exhibit 3D metal-organic frameworks with certain pore sizes, especially MOFs 1 and 5. Spectroscopic and crystallographic investigations demonstrate that the absorption and emission energies of the BODIPY chromophores are sensitive to the coordination modes. Moreover, in case 2, the transition metal centers coordinated with the dicarboxylate ligands L(2-) are capable of forming the two BODIPY units in coplanar arrangements (θ = 37.9°), simultaneously suppressing the uncommon J-dimer absorption band centered at 705 nm with a long tail into the near-infrared region at room temperature. On the other hand, in comparison with the ligand H2L, the emission of monomer-like BODIPY in case 3 is enhanced in the solid state by a considerably long distance between the parallel BODIPY planes (about 14.0 Å).

Two 3D Cd(II) Metal–Organic Frameworks Linked by Benzothiadiazole Dicarboxylates: Fantastic S@Cd6 Cage, Benzothiadiazole Antidimmer, and Dual Emission

On the basis of the same benzothiadiazole (BTD) ligand 2,1,3-benzothiadiazole-4,7-dicarboxylic acid (H2L), two new isomers of three-dimensional (3D) BTD-derived Cd(II) metal-organic frameworks 1-2 {[S@Cd6L6]·xH2O}n were obtained by the different solvothermal reactions, which were structurally similar. Surprisingly, structural analyses reveal that in 1 or 2, one free sulfur atom was fixed in a Cd(II) cluster cage by strong intermolecular interaction to form the secondary building unit (SBU) S@Cd6. Each SBU S@Cd6 is connected by six L2- ligands and further extended into the 3D porous framework. In this work, the BTD antidimmer was evidenced by structural analysis and photophysical study. Furthermore, either 1 or 2 showed the uncommon dual emission, while only one emission was observed in the solution of ligand H2L. The dual-emission mechanism was also realized by the structural analysis and photophysical study. Interestingly, although there is slight difference in structure (regular octahedral cage in 1 and slightly distorted octahedral cage in 2), the changes in N2 adsorption capability and photophysical performance between 1 and 2 are obvious, where 2 shows smaller Brunauer-Emmett-Teller surface area, broader absorption of antidimmer, and longer dual-emission lifetimes. Interestingly, either 1 or 2, the dual emission was clearly red-shifted by increasing the solvent polarity or the acidity of ambience, respectively.

From Surprising Solvothermal Reaction to Uncommon Zinc(II)-Catalyzed Aromatic C–H Activation Reaction for Direct Nitroquinoline Synthesis

In this work, we first found a surprising solvothermal reaction for direct dinitration of quinoline derivative. To explore the application in direct nitroquinoline synthesis, this reaction was subsequently modified as an equivalent reaction in a Schlenk tube. More significantly, after a constant attempt, nitrated derivative was obtained in optimized condition with a zinc(II) sulfate catalyst, where some substrates with strong electron-withdrawing group were first nitrated by a directly catalyzed condition. This new zinc(II)-catalyzed aromatic C-H activation reaction is the first example of direct dinitration by a single catalyst, which will be a new facile and environmentally friendly strategy to access synthetically useful nitroquinoline derivative.