Tris-Functionalized Polyoxotungstovanadate-Mediated Antitumor Efficacy Involves Multiple Cell Death Pathways

Polyoxometalates (POMs) are promising inorganic drug candidates for cancer chemotherapy. They are becoming attractive because of their easy accessibility and low cost. Herein, we report the synthesis and antitumor activity studies of four Lindqvist-type POMs with mixed-addenda atoms Na2[V4W2O16{(OCH2)3CR}] (R=-CH2OH, -CH3, -CH2CH3) and (Bu4N)2[V3W3{(OCH2)3CH2OOCCH2CH3}]. Compared with the current clinical applied antitumor drug 5-fluorouracil (5-FU) or Gemcitabine, analysis of MTT/CCK-8 assay, colony formation and wound healing assay revealed that the {V4W2} POMs had acceptable cytotoxicity in normal cells (293T) and significant inhibitory effects on cell proliferation and migration in three human tumor cell lines: human lung carcinoma cells (A549), human cervical carcinoma cells (HeLa), and human breast cancer cells (MCF-7). Interestingly, among the POMs analyzed, the therapeutic index (TI) of the {V4W2} POM with R= -CH2OH was relatively the most satisfactory. Thus, it was subsequently used for further studies. Flow cytometry analysis showed it prompted cellular apoptosis rate. qRT-PCR and Western blotting analysis indicated that multiple cell death pathways were activated including apoptosis, autophagy, necroptosis and pyroptosis during the POM-mediated antitumor process. In conclusion, our study shows that the polyoxotungstovanadate has great potential to be developed into a broad-spectrum antitumor chemotherapeutic drug.

A 3D supramolecular architecture based on 2,2′-oxybis(benzoic acid) and trans-1,2-bis(4-pyridyl)ethylene as ligands for Co(II)

The reaction of CoCl2·6H2O with mixed ligands of 2,2′-oxybis(benzoic acid) (2,2′-H2oba) and trans-1,2-bis(4-pyridyl)ethylene (bpe) under hydrothermal conditions produced a new 3D cobalt(II) supramolecular architecture {[Co(oba)(bpe)(H2O)]·1/2bpe} n (1), which was structurally characterized by elemental analysis, infrared spectroscopy, thermogravimetric analyses, and single-crystal X-ray diffraction. The results show that the Co(II) ions are connected to form an infinite polymeric chain by bpe ligands in complex 1. Due to strong intermolecular O–H···O hydrogen bonds, the adjacent chains are connected to generate a double-chain structure. These double chains are joined by O–H···N hydrogen bonding to produce a 2D supramolecular architecture. Furthermore, through intermolecular C–H···O hydrogen bonds, the layers are linked into a 3D supramolecular structure. Magnetic susceptibility measurements have indicated that complex 1 shows weak antiferromagnetic interactions between adjacent Co(II) ions.

Biphenyl-2,4,6,3',5'-pentacarboxylic acid as a tecton for six new Co(II) coordination polymers: pH and N-donor ligand-dependent assemblies, structure diversities and magnetic properties

Six new Co(ii)-based mixed-ligand coordination polymers, namely, [Co2(H3bppc)2(2,2'-bpy)4]·H2O (), [Co2(Hbppc)(2,2'-bpy)2(H2O)]·H2O (), [Co(H2bppc)(H-bpp)]·2H2O (), [Co3(μ3-OH)(bppc)(dps)(CH3CH2OH)]·4H2O (), [Co2(bppc)(bib)(H2O)4]·(H2-bib)0.5·(H2O)3 (), and [Co2(Hbppc)(bix)2]·2H2O (), (H5bppc = biphenyl-2,4,6,3',5'-pentacarboxylic acid, 2,2'-bpy = 2,2'-bipyridine, bpp = 1,3-bis(4-pyridyl)propane, dps = 4,4'-sulfanediyldipyridine, bib = 1,4-bis(imidazol-1-yl)benzene, bix = 1,4-bis(imidazol-1-ylmethyl)benzene), have been obtained under solvothermal conditions. exhibits a 3D supramolecular framework based on a [Co2(H3bppc)2(2,2'-bpy)4] unit. has a (3,4)-connected dmc net with a (4·8(2))(4·8(5)) topology containing alternate binuclear metal clusters and single metal centres. shows a 3D supramolecular architecture constructed from ladder-like arrays decorated with H-bpp. exhibits a binodal (5,7)-connected 3D network based on trinuclear [Co3(μ3-OH)](5+) units with an unusual (3·4(6)·5(2)·6)(3(2)·4(6)·5(7)·6(5)·7) topology. features a (4,6)-connected 3D fsc open framework with binuclear [Co2(H2O)(COO)](3+) units as nodes, and H2-bib and water molecules located in the voids of its framework by hydrogen bonds. possesses a 3D net containing unusual 2D polyrotaxane sheets. Topological analysis reveals that has a (3,4,4)-connected 3D network with a (4·6·7(4))(4·6·7)(6·7(2)·10(2)·11) topology. The structural difference of and is due to the different pH values of the reaction system. Though complexes were synthesised under similar reaction conditions, the carboxylic groups of H5bppc were partially deprotonated in , and and fully deprotonated in and . Complexes display diverse structures depending on different N-donor ligands and the coordination modes of the multicarboxylate ligand. Variable-temperature magnetic susceptibility measurements reveal that complexes show antiferromagnetic interactions.

Distinct 3D CdII Coordination Polymers with 1,2-Naphthalenedicarboxylate Regulated by Dipyridyl Co-Ligands with Different Spacers

Two distinct three-dimensional (3D) CdII coordination polymers with 1,2-naphthalenedicarboxylate (ndc2–) and dipyridyl co-ligands have been synthesized under hydrothermal conditions. Interestingly, the slight difference in the two 4,4′-dipyridyl building blocks, namely, 1,2-bi(4-pyridyl)ethane (bpp) and 1,2-bi(4-pyridyl)ethene (bpe) with C–C or C=C spacers, results in the significant structural divergence of the resultant coordination polymers. Structural analysis reveals that complexes [Cd(ndc)(bpp)(H2O)]n (1) and {[Cd5(ndc)4(bpe)2(OH)2](H2O)1.5}n (2) are constructed by discrete metal–carboxylate dimeric units and metal–carboxylate chains, respectively, which are further extended by bpp or bpe linkers to form the inclined interpenetrated two-dimensional (2D)→3D network for 1 and the 3D porous framework for 2. This result reveals that the flexibility of auxiliary ligands plays an important role in the structural assemblies of coordination networks. The thermal and luminescence properties of both complexes were also investigated in solid state.

The first case of actinide triple helices: pH-dependent structural evolution and kinetically-controlled transformation of two supramolecular conformational isomers

A kinetically-controlled transformation occurs between two supramolecular isomers of the first actinide triple helices based on conformational changes of phenanthroline coordinated to the asymmetric uranyl equatorial plane.

Three novel lanthanide metal-organic frameworks (Ln-MOFs) constructed by unsymmetrical aromatic dicarboxylatic tectonics: synthesis, crystal structures and luminescent properties

Three novel Ln(III)-based coordination polymers, {[Ln₂ (2,4-bpda)₃ (H₂O)_x]·yH₂O}_n (Ln = La (III) (1), x = 2, y = 0, Ce (III) (2), Pr (III) (3), x = 4, y = 1) (2,4-H₂bpda = benzophenone-2,4-dicarboxylic acid) have been prepared via a solvothermal method and characterized by elemental analysis, IR, and single-crystal X-ray diffraction techniques. Complex 1 exhibits a 3D complicated framework with a new 2-nodal (3,7)-connected (4²·5) (4⁴·5¹·6⁶·8) topology. Complexes 2 and 3 are isomorphous, and feature a 3D 4-connected (6⁵·8)-CdSO₄ network. Moreover, solid-state properties such as thermal stabilities and luminescent properties of 1 and 2 were also investigated. Complex 1 crystallized in a monoclinic space group P2₁/c with a = 14.800 (3), b = 14.500 (3), c = 18.800 (4) Å, β = 91.00 (3), V = 4033.9 (14) ų and Z = 4. Complex 2 crystallized in a monoclinic space group Cc with a = 13.5432 (4), b = 12.9981 (4), c = 25.7567 (11) Å, β = 104.028 (4), V = 1374.16 (7) ų and Z = 4.

A one-dimensional cobalt(II) coordination polymer based on 2,4'-oxydibenzoic acid: poly[[[diaquabis[2-(4-carboxyphenoxy)benzoato-κO(1)]cobalt(II)]-μ-4,4'-bipyridine-κ(2)N:N'] dihydrate]

The reaction of CoSO4 with 2,4-oxydibenzoic acid (H2oba) and 4,4'-bipyridine (bipy) under hydrothermal condition yielded a new one-dimensional cobalt(II) coordination polymer, {[Co(C14H9O5)2(C10H8N2)(H2O)2]·2H2O}n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, magnetic properties and single-crystal X-ray diffraction. The Co(II) ions are connected by bipy ligands into infinite one-dimensional chains. The Hoba(-) ligands extend out from the two sides of the one-dimensional chain. O-H···O hydrogen bonding extends these chains into a two-dimensional supramolecular architecture.