Four new diarylethene derivatives based on thiophene or thiazole moieties were designed and synthesized, and the structures of compounds 4a and 5a were determined by single-X-ray diffraction analysis. All of these compounds showed reversible photochromic reactions and notable fluorescence photo-switches in solution. Furthermore, diarylethenes 4a and 5a also showed good photochromism in single crystal phase. The electron-donating and electron-withdrawing substituents play the same role in the photochromic process: red-shifted absorption and fluorescence (1a and 2a compared with 3a). The fluorescent modulation efficiencies of asymmetrical diarylethenes 4 and 5 were significantly enhanced compared with the similar dithienylethenes, and the fatigue resistance of 5 was much better than 4, which showed that the diarylethene bearing electron-withdrawing group could improve its fatigue resistance.

We report two new 3D structures, [Zn₃(bpdc)₃(2,2′-dmbpy)] (DMF)_x(H₂O)_y (1) and [Zn₃(bpdc)₃(3,3′-dmbpy)]⋅(DMF)₄(H₂O)_0.5 (2), by methyl functionalization of the pillar ligand in [Zn₃(bpdc)₃(bpy)] (DMF)₄⋅(H₂O) (3) (bpdc=biphenyl-4,4′-dicarboxylic acid; z,z′-dmbpy=z,z′-dimethyl-4,4′-bipyridine; bpy=4,4′-bipyridine). Single-crystal X-ray diffraction analysis indicates that 2 is isostructural to 3, and the power X-ray diffraction (PXRD) study shows a very similar framework of 1 to 2 and 3. Both 1 and 2 are 3D porous structures made of Zn₃(COO)₆ secondary building units (SBUs) and 2,2′- or 3,3′-dmbpy as pillar ligand. Thermogravimetric analysis (TGA) and PXRD studies reveal high thermal and water stability for both compounds. Gas-adsorption studies show that the reduction of surface area and pore volume by introducing a methyl group to the bpy ligand leads to a decrease in H₂ uptake for both compounds. However, CO₂ adsorption experiments with 1′ (guest-free 1) indicate significant enhancement in CO₂ uptake, whereas for 2′ (guest-free 2) the adsorbed amount is decreased. These results suggest that there are two opposing and competitive effects brought on by methyl functionalization: the enhancement due to increased isosteric heats of CO₂ adsorption (Q_st), and the detraction due to the reduction of surface area and pore volume. For 1′, the enhancement effect dominates, which leads to a significantly higher uptake of CO₂ than its parent compound 3′ (guest-free 3). For 2′, the detraction effect predominates, thereby resulting in reduced CO₂ uptake relative to its parent structure 3′. IR and Raman spectroscopic studies also present evidence for strong interaction between CO₂ and methyl-functionalized π moieties. Furthermore, all compounds exhibit high separation capability for CO₂ over other small gases including CH₄, CO, N₂, and O₂.

Plastrum Testudinis (PT) is often used as an important traditional Chinese medicine to treat bone diseases in China for centuries. To identify active components of PT involved in promoting proliferation of MSCs, PT was extracted with ethyl acetate and separated by silica gel column chromatography with gradient elution. Sixteen (Ts-1 ∼ 16) components were obtained, which were biologically evaluated by MTT assay and flow cytometry on the proliferation of rat marrow-derived mesenchymal stem cells (rMSCs). Results indicated that Ts-12 could induce the proliferation compared with control group (p < 0.05), while Ts-4 exhibited inhibitive effect. The chemical components of PT which regulated the proliferation of rMSCs were investigated by Gas Chromatography-Mass Spectrometry (GC-MS), HPLC, and nine standard compounds. The experimental results suggested that palmitic acid methyl ester and cholesterol myristate, which identified from Ts-12, possessed proliferative activity while stearic acid found in Ts-4 showed inhibition.

Several transition metal complexes based on 2,3-bis(2,4,5-trimethyl-3-thienyl)maleic anhydride (DTE) bearing terpyridine (TPY) have been designed and synthesized. Furthermore, the photochromism of the free ligand and the influence of transition metal moieties on the photochemical properties have been thoroughly characterized by monitoring the changes in their UVvis spectra. Compounds 3–6 all display excellent response to UV irradiation, especially Co complex 5 with optimum sensitivity that took only 5 s to reach photostationary state. The photochromic properties of DTE unit have been found to be strongly influenced by the bridging transition metals, as complexes 4 (L–Zn–L) and 6 (L–Ru–L) exhibit much better photochromic properties in tetrahydrofuran solution than complex 5 (L–Co–L) and the free ligand 3 (L). It is worth noting that the optical/chemical thermal stabilities of photochromic compounds 3–6 are all greatly improved after the precursor functionalized with TPY and further coordinated with metal ions. Copyright © 2012 John Wiley & Sons, Ltd.

The design, synthesis, and structural characterization of two new microporous metal-organic framework (MMOF) structures is reported; Zn(BDC)(DMBPY)_0.5·(DMF)_0.5(H₂O)_0.5 (1; H₂ BDC = 1,4-benzenedicarboxylic acid; DMBPY=2,2′-dimethyl-4,4′-bipyridine) and Zn(NDC)(DMBPY)_0.5·(DMF)₂ (2; H₂NDC = 2,6-naphthalenedicarboxylic acid, DMF=N,N,-dimethylformamide), which are obtained by functionalizing a pillar ligand with methyl groups. Both compounds are 3D porous structures of the Zn₂(L)₂(P) type and are made of a paddle-wheel Zn₂(COO)₄ secondary building unit (SBU), with the dicarboxylate and DMBPY as linker (L) and pillar (P) ligands, respectively. Comparisons are made to the parent structures Zn(BDC)(BPY)_0.5·(DMF)_0.5(H₂O)_0.5 (3; BPY = 4,4′-bipyridine) and Zn(NDC)(BPY)_0.5·(DMF)_1.575 (4) to analyze and understand the effect of methyl functionalization. CO₂-adsorption studies indicate substantially enhanced isosteric heats of CO₂ adsorption (Q_st) for both compounds, as a result of adding methyl groups to the BPY ligand. The CO₂ uptake capacity, however, is affected by two opposing and competing factors: the enhancement due to increased MMOF–CO₂ interactions (higher Q_st values) and detraction due to the surface area and pore-volume reduction. For 1′ (the guest-free form of 1), the positive effect dominates, which leads to a significantly higher uptake of CO₂ than that of its parent structure 3′ (the guest-free form of 3). In 2′ (the guest-free form of 2), however, the negative effect rules, which results in a slightly lower CO₂ uptake with respect to 4′ (the guest-free form of 4). All four compounds exhibit a relatively high separation capability for carbon dioxide over other small gases, including CH₄, N₂, and O₂. The separation ratios of CO₂ to O₂ and N₂ (at 298 K and 1 atm) are 39.8 and 23.5 for compound 1′, 57.7 and 40.2 for 2′, 25.7 and 29.5 for 3′, 89.7, and 20.3 for 4′, respectively. IR and Raman spectroscopic characterization of CO₂ interactions with 1′ and 2′ provides indirect support of the importance of the methyl groups in the interaction of CO₂ within these systems.