The development of active and selective non-noble metal-based catalysts for the chemoselective reduction of nitro compounds in aquo media under mild conditions is an attractive research area. Herein, the synthesis of subnanometric and stable cobalt nanoclusters, covered by N-doped carbon layers as core–shell (Co@NC-800), for the chemoselective reduction of nitroarenes is reported. The Co@NC-800 catalyst was prepared by the pyrolysis of the Co(tpy)₂ complex impregnated on Vulcan carbon. In fact, the use of a molecular complex based on six N–Co bonds drives the formation of a well-defined and distributed cobalt core–shell nanocluster covered by N-doped carbon layers. In order to elucidate its nature, it has been fully characterized by using several advanced techniques. In addition, this as-prepared catalyst showed high activity, chemoselectivity and stability toward the reduction of nitro compounds with H₂ and under mild reaction conditions; water was used as a green solvent, improving the previous results based on cobalt catalysts. Moreover, the Co@NC-800 catalyst is also active and selective for the one-pot synthesis of secondary aryl amines and isoindolinones through the reductive amination of nitroarenes. Finally, based on diffraction and spectroscopic studies, metallic cobalt nanoclusters with surface CoN_x patches have been proposed as the active phase in the Co@NC-800 material.

The catalytic aerobic cyclohexane oxidation to cyclohexanol and cyclohexanone (KA oil) is an industrially relevant reaction. This work is focused on the synthesis of tailor-made catalysts based on the well-known Co₄O₄ core in order to successfully deal with cyclohexane oxidation reaction. The catalytic activity and selectivity of the synthesized catalysts can be correlated with the electronic density of the cluster, modulated by changing the organic ligands. This is not trivial in cyclohexane oxidation. Furthermore, the reaction mechanism is discussed on the basis of kinetics and spin trapping experiments, confirming that the electronic density of the catalyst has a clear influence on the distribution of the reaction products. In addition, in situ Raman spectroscopy was used to characterize the oxygen species formed on the cobalt cluster during the oxidation reaction. Altogether, it can be concluded that the catalyst with the highest oxidation potential promotes the formation of peroxide and superoxide species, which is the best way to oxidize inactivated CH bonds in alkanes. Finally, based on the results of the mechanistic studies, the contribution of these cobalt oxide clusters in each single reaction step of the whole process has been proposed.

A major challenge in hydrogen production from water electrolysis is the slow kinetics of oxygen evolution (OER). Applying an alternating magnetic field (AMF) to ferromagnetic metal nanoparticles on electrodes has gained attention due to the generation of a thermally activated electrocatalyst, which can boost OER performance. This work studies the influence of external parameters and intrinsic characteristics of carbon‐encapsulated cobalt MOF‐derived nanoparticles deposited onto graphite paper electrodes on the electrocatalytic AMF‐OER coupled process. Specifically, the impact of AMF strength, the electrolyte composition (concentration and cation nature) and cobalt content on the electrocatalytic AMF‐OER performance are thoroughly investigated. Results reveal that AMF significantly boosts OER activity of Co@C ‐based electrodes, their enhancement being strongly dependent on the electrolyte composition. Furthermore, both the heating capacity of the herein synthesized catalyst for magnetic hyperthermia and their structural features remain intact after an intense and prolonged electrocatalytic AMF‐OER experiment. No signs of sintering, leaching, or particle size increase, which are typical issues observed when metal nanoparticles are subjected to an intense external magnetic field, have been found. This underscores the high operational stability of this catalyst. These findings provide new insights into thermal AMF‐assisted alkaline water oxidation for developing high‐performance catalysts for enhanced electrocatalysis.

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.