High-Nuclear Vanadoniobate {Nb48V8} Multiple-Strand Wheel.

An unprecedented octavanadium-substituted polyoxoniobate Na18[Nb48V8(OH)30O130] · 33H2O (1), with a multiple-strand wheel structure, was successfully synthesized via a conventional aqueous method, which represents the largest vanadoniobate cluster reported to date. Single-crystal X-ray diffraction, ESI-MS spectrum, IR spectra, and UV-vis spectra were investigated. In addition, photocatalytic H2 evolution activity for 1 under UV light was observed with TEA as a sacrificial electron donor.

A novel stealth liposomal topotecan with amlodipine: apoptotic effect is associated with deletion of intracellular Ca2+ by amlodipine thus leading to an enhanced antitumor activity in leukemia.

The objectives of the present study were to define whether amlodipine induces apoptosis and what mechanism is involved in the process in human resistant and non-resistant leukemia cells following co-administration of stealth liposomal topotecan with amlodipine, a novel antiresistant liposomes developed by our institution. In three leukemias, K562, HL-60, and multidrug resistant (MDR) HL-60, cytotoxicity of topotecan was potentiated by amlodipine, while topotecan alone was resistant to MDR HL-60 cells. In two selected K562 or MDR HL-60 cells, the apoptotic effects were increased by addition of amlodipine, showing a dose-dependent manner. The activities of caspase 3 and 7 (marked as caspase 3/7), and caspase 8 were significantly activated by topotecan with amlodipine co-treated as the stealth liposomes. The deletions of intracellular Ca2+ stores induced by amlodipine correlated with the activated activities of caspase 3/7, or 8, respectively. In xenograft model with MDR HL-60 in nude mice, antitumor activity of stealth liposomal topotecan with amlodipine was significantly enhanced as compared to that of stealth liposomal topotecan or topotecan alone. In conclusion, apoptotic effect is associated with deletion of intracellular Ca2+ by amlodipine through activation of caspase 8 and then 3/7 activities. The enhanced antitumor activities by stealth liposomal topotecan with amlodipine are mainly due to the potentiating apoptotic effect and reversing the resistance by amlodipine. Stealth liposomal encapsulation of anticancer agent with a modulator may provide a novel strategy for improving the chemotherapeutic effects.

Anderson-like alkoxo-polyoxovanadate clusters serving as unprecedented second building units to construct metal-organic polyhedra.

Unprecedented Anderson-like alkoxo-polyoxovanadate [V6O6(OCH3)9(µ6-SO4)(COO)3](2-) polyanions can serve as 3-connected second building units (SBUs) that assemble with dicarboxylate or tricarboxylate ligands to form a new family of metal organic tetrahedrons of V4E6 and V4F4 type (V = vertex, E = edge, and F = face). To our knowledge, this alkoxo-polyoxovanadate-based SBU is the first ever reported.

Polyoxovanadate-based organic-inorganic hybrids: from {V5O9Cl} clusters to nanosized octahedral cages.

Three polyoxovanadate-based metal-organic polyhedra (denoted as VMOP-1, -2, and -3), adopting isostructural discrete octahedral cage geometries, were successfully synthesized under solvothermal conditions. These structures are all built up from the same pentavanadate {V5O9Cl} cluster connected by linear bidentate ligands (H2L1 = H2BDC, H2L2 = H2BDC-NH2, H2L3 = H2BDC-Br), respectively.

Synthesis, structures, and magnetic properties of metal-organic polyhedra based on unprecedented {V7} isopolyoxometalate clusters.

Two isostructural vanadium-based metal-organic polyhedra (denoted as VMOP-16 and VMOP-17) were synthesized by a solvothermal method, which are built from unprecedented {V7} isopolyoxometalate clusters and dicarboxylate ligands. To our knowledge, the {V7} second building unit is reported for the first time and features the highest nuclearity of vanadium-oxygen clusters compared with reported vanadium-based MOPs.

Spontaneous chiral resolution of a rare 3D self-penetration coordination polymer for sensitive aqueous-phase detection of picric acid.

Two unprecedented homochiral enantiomers based on two different kinds of rigid ligands, namely [Cd(NDC)L]2·H2O (1R and 1L), have been synthesized under hydrothermal conditions through spontaneous resolution. Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR, and thermogravimetric (TG) analysis. The resulting framework 1, constructed by four kinds of homo-handed helical chains represents the first 3D self-penetrating framework formed by decoration of single (10,3)-a net with helical chains. The single (10,3)-a net in 1 formed by three kinds of different homo-handed helical chains is different from the standard one, which should be ascribed to the usage of V-shaped ligand L. A unique self-penetration motif can be discovered in 1 where one helical chain alternately passes through 10-membered shortest circuits linked to each other and in contrary, the corresponding circuits are bound to the helical chain. Interestingly, 1 exhibits fluorescent emission in both the solid and solution phase. The uncoordinated nitrogen atom and amino group from the triazole core on the crystal surface make it suitable to detect picric acid in water. The luminescence intensity of 1 in water can be efficiently quenched by the addition of picric acid (PA). The sensitive detection of PA can be continuously performed for at least five cycles without diminishing the fluorescence intensity and destroying the framework structure of 1. The possible quenching mechanisms for PA are also investigated.

An organic-inorganic hybrid photocatalyst based on sandwich-type tetra-Co-substituted phosphotungstates with high visible light photocatalytic activity.

A novel 3D organic-inorganic hybrid framework constructed from tetra-Co(II)-substituted sandwich-type phosphotungstates with a rare 8-connected bcu topology is reported, which exhibited highly efficient photocatalysis activity under visible light and could be used for 5 cycles without any obvious decrease in activity.

Periodic tiling of triangular and square nanotubes in a cationic metal-organic framework for selective anion exchange.

A unique cationic metal-organic framework was synthesized by connecting the neutral rod-shaped secondary building unit with a cationic dicarboxylate ligand. This framework showed a rare snub square tessellation pattern by the periodic tiling of triangular and square nanotubes. The charge- and size-dependent ion-exchange of anion dyes was investigated.

A novel [4 + 3] interpenetrated net containing 7-fold interlocking pseudo-helical chains and exceptional catenane-like motifs.

A novel interpenetrating metal-organic framework, namely [Zn(3)L(2)(oba)(3)(H(2)O)(2)]·(4)H(2)O (1), has been synthesized under hydrothermal conditions. Its structure was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR, and thermogravimetric (TG) analysis. In the structure of 1, the rigid and flexible V-shaped ligands link Zn(ii) to form a 3D structure where two types of helices and four types of pseudo-helical chains containing three pairs of enantiomers and two pairs of conformational isomers have been characterized. One such 3D framework incorporates six identical networks to form a 7-fold interpenetrated 3D framework. From the topological analysis, the Zn(ii) ions act as three- and four-connected nodes, and oba as well as L are linkers. The framework of compound can be classified as a new (6(3))2(6(5)·8) topology, which is a novel (3,3,4)-connected [4 + 3] 7-fold interpenetrating net showing 7-fold interlocking pseudo-helical chains and a unique catenane-like motif with Hopf links. In addition, the luminescence properties of the compound are discussed.

The copper(I) metal azolate framework showing unusual coordination mode for the 1,2,4-triazole derivative and photocatalytic activity.

A unique three-dimensional metal azolate framework containing a tetranuclear copper cluster constructed by six 1,2,4-triazole units was synthesized in which the 1,2,4-triazole units show unusual bridging "crevice" coordination mode with their 1- and 2-positioned sp(2) N-atoms as symmetrically bridging centers. The photocatalytic activities of as-prepared compound were tested by degradation of rhodamine-B (RB) under different light irradiation.

A novel organic-inorganic hybrid constructed from the Nyman-type dititanoniobate [Ti2Nb8O28](8-) and copper-organic cations.

A new organic-inorganic hybrid titaniobate compound, [Cu(en)2][Cu(en)2(H2O)2]3[Ti2Nb8O28]·8H2O (1) (en = ethylenediamine), was successfully synthesized, characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA) and UV-Vis diffuse reflectance spectroscopy and its photoluminescence studied.

Enhanced therapeutic effects on the multi-drug resistant human leukemia cells in vitro and xenograft in mice using the stealthy liposomal vincristine plus quinacrine.

The multi-drug resistance (MDR) could be caused by the over-expression of adenosine triphosphate binding cassette transporters such as p-glycoprotein, thereby resulting in the efflux of anti-cancer drugs from the cells. An anti-resistant stealthy liposomal vincristine plus quinacrine was defined in this study. Human chronic myelogenous leukemia K562 and MDR K562 cells were included for comparisons. Anti-tumor activity studies were performed on female BALB/c nude mice with MDR K562 cell xenografts. Results showed that quinacrine was effective in reversing the resistance in the MDR K562 cells, and enhanced the anti-tumor effect of vincristine in K562 cells. The caspase-9 and -3 activities in the MDR K562 and K562 cells were increased with the dose rise of quinacrine. In the MDR K562 cell xenografts in mice, the anti-resistant tumor effect of the stealthy liposomal vincristine plus quinacrine was evidently observed. The enhanced anti-tumor effects of vincristine by quinacrine in the resistant/non-resistant K562 cells could be because of the direct injury and the potentiating apoptotic effect of vincristine via activating the initiator caspase-9 and subsequently the effector caspase-3, and the long circulatory effect of stealthy liposomes. The stealthy liposomal encapsulation of vincristine plus quinacrine could be a potential therapeutic approach for resistant human leukemia.