A new cobalt metal-organic framework (2D-Co-MOF) based on well-defined layered double cores that are strongly connected by intermolecular bonds has been developed. Its 3D structure is held together by π-π stacking interactions between the labile pyridine ligands of the nanosheets. In aqueous solution, the axial pyridine ligands are exchanged by water molecules, producing a delamination of the material, where the individual double nanosheets preserve their structure. The original 3D layered structure can be restored by a solvothermal process with pyridine, so that the material shows a "memory effect" during the delaminationpillarization process. Electrochemical activation of a 2D-Co-MOF@Nafion-modified graphite electrode in aqueous solution improves the ionic migration and electron transfer across the film and promotes the formation of the electrocatalytically active cobalt species for the oxygen evolution reaction (OER). The so-activated 2D-Co-MOF@Nafion composite exhibits an outstanding electrocatalytic performance for the OER at neutral pH, with a TOF value (0.034 s-1 at an overpotential of 400 mV) and robustness superior to those reported for similar electrocatalysts under similar conditions. The particular topology of the delaminated nanosheets, with quite distant cobalt centers, precludes the direct coupling between the electrocatalytically active centers of the same sheet. On the other hand, the increase in ionic migration across the film during the electrochemical activation stage rules out the intersheet coupling between active cobalt centers, as this scenario would impair electrolyte permeation. Altogether, the most plausible mechanism for the O-O bond formation is the water nucleophilic attack to single Co(IV)-oxo or Co(III)-oxyl centers. Its high electrochemical efficiency suggests that the presence of nitrogen-containing aromatic equatorial ligands facilitates the water nucleophilic attack, as in the case of the highly efficient cobalt porphyrins.

It has been developed the synthesis of a new microporous Metal-Organic Framework (MOF) based on two Secondary Building Units (SBU), with dinuclear cobalt centers. The employing of a well-2 defined cobalt cluster results in an unusual topology of the Co 2 -MOF, where one of the cobalt centers has three open coordination positions, which has not precedent in MOF materials based on cobalt. Adsorption isotherms have revealed that Co 2 -MOF is in the range of best CO2 adsorbents among the carbon materials, with a very high CO2/CH4 selectivity. On the other hand, dispersion of Co 2 -MOF in an alcoholic solution of Nafion gives rise to a composite (Co 2 -MOF@Nafion) with a great resistance to hydrolysis in aqueous media and good adherence to graphite electrodes.In fact, it exhibits a high electrocatalytic activity and robustness for the oxygen evolution reaction (OER), with a TOF value superior to those reported for similar electrocatalysts. Overall, this work has provided the basis for the rational design of new cobalt OER catalysts and related materials employing well defined metal clusters as directing agents of MOF structure.

Alkene hydrosilylation is typically performed with Pt catalysts, but inexpensive base‐metal catalysts would be preferred. Here, we report a simple method for the use of air‐stable cobalt catalysts for anti‐Markovnikov alkene hydrosilylation that can be used under aerobic conditions without dry solvents or additives. These catalysts can be generated from low‐cost commercially available materials. In addition, these catalysts possess good catalytic ability for both hydrosilanes and hydroalkoxysilanes. Finally, a mechanistic study demonstrates that the silane and the catalyst generate a Co–H species in the course of the reaction, which has been observed by in situ Raman spectroscopy.

The development of active and selective non-noble metal-based catalysts for the chemoselective reduction of nitrocompounds able to work in aquo media under mild conditions is an attractive research area. Herein,...

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Chemical, pharmacological, and clinical research on anticancer coordination complexes has led to noteworthy anticancer drugs such as cisplatin, carboplatin and oxaliplatin. Although these compounds are effective chemotherapeutic agents in the treatment of different tumors, they are associated with high toxicity and numerous side effects. Several studies have shown that the range of platinum complexes with antitumor activity is not limited to structural analogs of cisplatin. Therefore, the development of convenient anticancer drugs that can be effectively used for the treatment of human tumors has become the main goal of most research groups in this field. In this sense, active platinum complexes without NH groups, transplatinum complexes, multinuclear complexes, cationic complexes, and several classes of palladium(II) complexes have emerged. Herein, the synthesis and characterization of two Pt(II) or Pd(II) complexes with PyTz (2-(2-pyridyl)iminotetrahydro-1,3-thiazine), a thiazine derivative ligand, with the formula [MCl2(PyTz)]·C2H6O (M = Pt(II) or Pd(II)) were reported. The potential anticancer ability of both complexes was evaluated in epithelial cervix carcinoma HeLa, human ovary adenocarcinoma SK-OV-3, human histiocytic lymphoma U-937, and human promyelocytic leukemia HL-60 cell lines. Interestingly, the Pt(II) complex showed great cytotoxic potential against all tumor cell lines tested, whereas the Pd(II) complex displayed slight antitumor actions.

Development of well-defined tetranuclear cobalt coordination compounds with modulable electron density as active and selective catalysts for aerobic cyclohexane oxidation.

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