Two Compounds Constructed from Bimolybdenum-Capped Sandwich-Type Tetra-Ni-molybdogermanate and N‑Donor Multidentate Ligand

Two organic–inorganic hybrid bimolybdenum-capped tetra-Ni^II sandwich-type molybdogermanates, namely, (H₂L)₄[Ni₄(H₂O)₂­{B-α-GeMo₉O₃₄ (MoO₂)}₂]·6H₂O (<b>1</b>), [Ni₂(HL)₄(H₂O)₂]­[Ni₄(H₂O)₂­{B-α-GeMo₉O₃₄(MoO₂)}₂]·12H₂O (<b>2</b>), L = 2,4,5-tri­(4-pyridyl)­imidazole, were prepared with hydrothermal synthesis method and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, thermogravimetric analysis, and single-crystal X-ray diffraction. Their magnetic properties and electrochemical properties were investigated. The results show that compounds <b>1</b> and <b>2</b> contain a new bimolybdenum-capped sandwich-type heteropolymolybdate anion, [Ni₄(H₂O)₂­{B-α-GeMo₉O₃₄(MoO₂)}₂]^8–. The compound <b>1</b> is a zero-dimensional supramolecular compound, and the supramolecular architecture of compound <b>2</b> is constructed from covalent layers through hydrogen bonds and π–π interaction. The two compounds both present electrocatalytic activities for the reduction of nitrite

Functionalized Pentamolybdodiphosphate-Based Inorganic–Organic Hybrids: Synthesis, Structure, and Properties

Three inorganic–organic hybrid compounds based on functionalized pentamolybdodiphosphonopropionate anion [(HO₂CC₂H₄PO₃)₂Mo₅O₁₅]^4–, [Co₃(bipy)₄(H₂O)₆{(HO₂CC₂H₄PO₃)₂Mo₅O₁₅}₂]·(H₂bipy)₂·18H₂O (<b>1</b>), [Fe₃(bipy)₄(H₂O)₆{(HO₂CC₂H₄PO₃)₂Mo₅O₁₅}₂]·(H₂bipy)₂·18H₂O (<b>2</b>), and [Cu­(bipy)­(H₂O)₂{(HO₂CC₂H₄PO₃)₂Mo₅O₁₅}]·(H₂bipy)·4H₂O (<b>3</b>), where bipy = 4,4′-bipyridine, have been successfully synthesized at different pH values in aqueous solutions. In compound <b>1</b>, [(HO₂CC₂H₄PO₃)₂Mo₅O₁₅]^4– acts as a tridentate ligand and coordinates to the Co²⁺ ions of trimeric complex cations [Co₃(bipy)₄(H₂O)₆]⁶⁺ forming a layer. In <b>3</b> [(HO₂CC₂H₄PO₃)₂Mo₅O₁₅]^4– acts as a bidentate ligand and coordinates to the Cu²⁺ ions of complex chains [Cu­(bipy)­(H₂O)₂]_<i>n</i>^2<i>n</i>+, forming a different layer from that in <b>1</b>. The three compounds were characterized by elemental analysis, IR spectra, and TGA. In addition, their fluorescent properties and magnetic properties have also been investigated

Semiconductor/Piezoelectrics Hybrid Heterostructures with Highly Effective Gate-Tunable Electrotransport and Magnetic Behaviors

We report the epitaxial growth of oxygen deficient titanium dioxide thin films on 0.7Pb­(Mg_1/3Nb_2/3)­O₃-0.3PbTiO₃ (PMN-PT) single crystals and realized highly effective in situ electrostatic manipulation of electrotransport and magnetism of TiO_2−δ films via gate voltages. Upon the polarization switching in the PMN-PT, the carrier density of the TiO_2−δ film could be reversibly modified, resulting in a large nonvolatile resistivity modulation by ∼51% at <i>T</i> = 300 K, approximately 4–12 times larger than that of other transition-metal oxide film/PMN-PT structures. By taking advantage of in situ manipulation of the carrier density via gate voltages, we found that competition between the trap of electrons by the Ti³⁺-<i>V</i>_O pairs and that by the positive polarization charges at the interface results in a significant resistivity relaxation upon the polarization switching, and revealed that magnetization is inversely correlated with the carrier density of the TiO_2−δ film. Such hybrid structures combining materials with dissimilar functionalities may have potential applications in multifunctional devices which can take advantage of the useful and unique properties of both materials

Two new anthraquinone derivatives and one new triarylbenzophenone analog from <i>Selaginella tamariscina</i>

<p>Two new anthraquinone derivatives, selaginones A (<b>1</b>) and B (<b>2</b>), and one new triarylbenzophenone analog, selagibenzophenone B (<b>3</b>), were isolated from <i>Selaginella tamariscina</i> (Beauv.) Spring. Their structures were established by 1D-, 2D-NMR and HR-ESI-MS data. Compounds <b>1</b> and <b>2</b> represent the uncommon examples of aryl substituted anthraquinone derivatives. Especially, compound <b>2</b> is a unique anthranone with exceptional structural feature, in which a <i>p</i>-hydroxyphenyl moiety is attached to the C-10 position. Compound <b>3</b> is the second naturally occurring triarylbenzophenone and showed moderate activity against SMCC-7721 and MHCC97-H cell lines with IC₅₀ values of 39.8, 51.5 μM respectively.</p

New adenine analogues and a pyrrole alkaloid from <i>Selaginella delicatula</i>

<p>Phytochemical study on the <i>n</i>-BuOH extract of <i>Selaginella delicatula</i> lead to the isolation, characterization and structure elucidation of two new adenine analogues, delicatulines A (<b>1</b>) and B (<b>2</b>), one new pyrrole alkaloid (<b>4</b>), and five known compounds (<b>3</b>, <b>5</b>–<b>8</b>). These new substances all contain an aliphatic chain in their parent nucleus, which were unusual to find in plants. In the present study, they were identified from Selaginellaceae for the first time. The structures and absolute configurations of these new compounds were determined by a combination of NMR and CD spectroscopic analyses. Compounds <b>1</b>, <b>3</b> and <b>4</b> were evaluated for their inhibitory activities on HBV surface antigen and HBV DNA in HepAD38 cells. The results showed that these compounds had only weak or no inhibitive effects on HBV.</p