Wen-Juan Shi

Trinuclear-based Copper(I) Pyrazolate Polymers: Effect of Trimer π-Acid···Halide/Pseudohalide Interactions on the Supramolecular Structure and Phosphorescence

Under different situations, solvothermal reactions of 3,5-diethyl-4-(4-pyridyl)-pyrazole (HL) with CuX or CuX(2) (X = Cl, Br, I, and SCN) afforded five copper(I) coordination polymers, {CuX[CuL](3)·solvent}(n) (X = Cl, 1; Br, 2; I, 3; X = SCN and solvent = MeCN, 4) and {Cu(2)I(2)[CuL](3)}(n) (5). X-ray diffraction analyses show that all the complexes have trinuclear [CuL](3) (referred as Cu(3)) secondary building units featuring planar nine-membered Cu(3)N(6) metallocycles with three peripheral pyridyl groups as connectors, which are further linked by CuX or Cu(2)X(2) motifs to generate single- or double-strand chains. Interestingly, the Cu(I) atoms within the Cu(3) units in 1-5 behave as coordinatively unsaturated π-acid centers to contact soft halide/pseudohalide X atoms of CuX and Cu(2)X(2) motifs, which lead to novel sandwich substructures of [(Cu(3))(Cu(2)X(2))(Cu(3))] (X = Br, I, and SCN) in 2-4. In addition, both the π-acid [Cu(3)]···X contacts and intertrimer Cu···Cu interactions contribute to the one-dimensional (1D) double-strand and 2D/3D supramolecular structures of 1-5. All of these complexes exhibit high thermostability and bright solid-state phosphorescence upon exposure to UV radiation at room temperature. The emissions arise from the mixtures of metal-centered charge transfer, metal to ligand charge transfer, and halide-to-ligand charge transfer excited states, and can be tuned by intermolecular π-acid [Cu(3)]···halide/pseudohalide contacts.

A Cationic MOF with High Uptake and Selectivity for CO2 due to Multiple CO2 -Philic Sites.

The reaction of N-rich pyrazinyl triazolyl carboxyl ligand 3-(4-carboxylbenzene)-5-(2-pyrazinyl)-1H-1,2,4-triazole (H2 cbptz) with MnCl2 afforded 3D cationic metal-organic framework (MOF) [Mn2 (Hcbptz)2 (Cl)(H2 O)]Cl⋅DMF⋅0.5 CH3 CN (1), which has an unusual (3,4)-connected 3,4T1 topology and 1D channels composed of cavities. MOF 1 has a very polar framework that contains exposed metal sites, uncoordinated N atoms, narrow channels, and Cl(-) basic sites, which lead to not only high CO2 uptake, but also remarkably selective adsorption of CO2 over N2 and CH4 at 298-333 K. The multiple CO2 -philic sites were identified by grand canonical Monte Carlo simulations. Moreover, 1 shows excellent stability in natural air environment. These advantages make 1 a very promising candidate in post-combustion CO2 capture, natural-gas upgrading, and landfill gas-purification processes.

Two new coordination polymers with multiform helical features based on flexible dithioether ligands and CuCN: from self-penetrating to 3-fold interpenetrating structures

The solvothermal reactions of CuCN with two structure-related flexible 4-pyridyl dithioether ligands, bis(4-pyridylthio)methane (L1) and 1,2-bis(4-pyridylthio)ethane (L2), generated two novel three-dimensional (3D) coordination polymers: [(CuCN)5(L1)2]n (1) and [(CuCN)3(L2)]n (2), respectively. Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. Complex 1 is constructed by the interconnection of CuCN layers with L1 pillars to form an interesting self-penetrating 123 topological network with characteristic of four distinct helical chains. In 2, each L2 acting as a quadridentate μ3-bridge connects Cu atoms from three uncommon meso-helical CuCN chains, to give 3D framework containing 1D tubes constructed by two types of helical chains with opposite chirality. 2 exhibits a 3-fold interpenetrating network with a rare (62·10)2(6·102) topology. In addition, the solid state samples of 1 and 2 exhibited different luminescent properties at room temperature.

Structural diversity of coordination polymers assembled from adamantane dicarboxylates and conformational bis-triazole ligand

A series of new coordination polymers have been hydrothermally synthesized by the combination of adamantane dicarboxylates and long conformational bis-triazole ligand with Zn(II)/Co(II)/Cd(II) ions, formulated as {[Zn(ADC)(btmb)]·3H2O}n (1), {[Co2(ADC)2(btmb)2]·H2O}n (2), {[Cd(ADA)(btmb)(H2O)]·H2O}n (3), {[Zn(ADA)(btmb)0.5]·H2O}n (4), {[Co2(ADA)2(btmb)2]·H2O}n (5), [Cd2(ADA)2(btmb)2]n (6) (H2ADC = 1,3-adamantanedicarboxylic acid, H2ADA = 1,3-adamantanediacetic acid and btmb = 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl). All crystalline polymers have been structurally characterized by single-crystal X-ray diffraction, elemental analysis, IR, TGA and XRD. Crystal structural analysis reveals that complex 1 has a 1D infinite tubular structure. Complexes 2 and 3 possess the similar 2D undulating layer structure with (44)-sql network. Interestingly, only the polymer 2 displays a 2-fold parallel interpenetrating 2D → 2D framework. Complex 4 presents a binodal (3,4)-connected V2O5-type net. While both 5 and 6 feature binodal (3,5)-connected networks. In particular, intermolecular forces have important effects on the formation and strengthening of the supramolecular architecture. Structural diversities indicate that distinct adamantane dicarboxylates, conformational bis-trizaole ligands and the nature of metal ions play crucial roles in modulating structures and topologies of the final polymers. Moreover, the thermal stability of crystalline sample 1 has been investigated through TGA and VT-XRD measurements. The luminescent properties of 1, 3, 4 and 6 have been studied.