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Cancer remains a formidable challenge, requiring the constant pursuit of novel therapeutic agents and strategies. Scorpionates, known for their unique coordination properties, have recently gained attention for their anticancer potential. Traditionally applied in catalysis, these compounds have demonstrated notable cytotoxicity across various cancer cell lines, often surpassing the efficacy of conventional chemotherapeutics. This review addresses recent findings on scorpionate complexes, emphasizing the impact of metal choice and ligand design on biological activity. Copper and ruthenium scorpionates show promise, leveraging redox activity and mitochondrial disruption mechanisms to selectively induce cancer cell death. Ligand modifications, including sulfur-containing heterocycles and unsubstituted pyrazoles, have proven effective in enhancing cytotoxicity and selectivity. Furthermore, dipodal ligands show unique potential, with selective binding sites that improve stability and facilitate specific cellular interactions, such as targeting metastatic pathways. These findings highlight the largely unexplored potential of scorpionate complexes, positioning them as candidates for next-generation anticancer therapies. Continued research into structure–activity relationships and precise mechanisms of action could pave the way for developing highly potent and selective anticancer agents based on scorpionate chemistry.

Large-scale terephthalic acid production from the oxidation of p-xylene is an especially important process in the polyester industry, as it is mainly used in polyethylene terephthalate (PET) manufacturing, a polymer that is widely used in fibers, films, and plastic products. This review presents and discusses catalytic advances and new trends in terephthalic acid production (since 2014), innovations in terephthalic acid purification processes, and simulations of reactors and reaction mechanisms.

The development of sustainable processes and products through innovative catalytic materials and procedures that allow a better use of resources is undoubtedly one of the most significant issues facing researchers nowadays. Environmental and economically advanced catalytic processes for selective oxidation of alcohols are currently focused on designing new catalysts able to activate green oxidants (dioxygen or peroxides) and applying unconventional conditions of sustainable significance, like the use of microwave irradiation as an alternative energy source. This short review aims to provide an overview of the recently (2015–2020) discovered homogeneous aerobic and peroxidative oxidations of primary and secondary alcohols catalyzed by copper complexes, highlighting new catalysts with potential application in sustainable organic synthesis, with significance in academia and industry.

Despite great advances in the fight against cancer, traditional chemotherapy has been hindered by the dose dependent adverse side effects that reduce the usable doses for effective therapy. This has been associated to drug resistance in tumor cells that often cause relapse and therapy failure. These drawbacks have been tackled by combining different therapeutic regiments that prevent drug resistance while decreasing the chemotherapy dose required for efficacious ablation of cancer. In fact, new metallic compounds have been in a continuous development to extend the existing chemotherapy arsenal for these combined regimens. Here, we demonstrate that combination of a metallic compound (TS265), previously characterized by our group, with photothermy circumvents cells resistant to Doxorubicin (DOX). We first engendered a colorectal carcinoma cell line (HCT116) highly resistant to DOX, whose viability was diminished after administration of TS265. Cancer cell death was potentiated by challenging these cells with 14 nm spherical gold nanoparticles followed by laser irradiation at 532 nm. The combination of TS265 with photothermy lead to 65% cell death of the DOX resistant cells without impacting healthy cells. These results support the use of combined chemotherapy and photothermy in the visible spectrum as an efficient tool for drug resistant tumors.

The novel hydrosoluble silver coordination polymer [Ag(NO3)(μ-1κN;2κN′,N″-TPMOH)]n (1) (TPMOH = tris(1H-pyrazol-1-yl)ethanol) was obtained and characterized. While single crystal X-ray diffraction analysis of compound 1 disclosed an infinite 1D helical chain structure in the solid state, NMR analysis in polar solvents confirmed the mononuclear nature of compound 1 in solution. Compound 1 and the analogue [Ag(μ-1κN;2κN′,N″-TPMS)]n (2) (TPMS = tris(1H-pyrazol-1-yl)methane sulfonate) were evaluated with regard to their antimicrobial activities towards the Gram-negative Escherichia coli, Pseudomonas aeruginosa, and Burkholderia contaminans, the Gram-positive Staphylococcus aureus, and the fungal species Candida albicans and Candida glabrata. Compound 1 exhibited minimal inhibitory concentration (MIC) values ranging from 2 to 7.7 µg/mL towards the tested Gram-negative bacteria, 18 µg/mL towards the Gram-positive S. aureus, and 15 and 31 µg/mL towards C. albicans and C. glabrata, respectively. Compound 2 was less effective towards the tested bacteria, with MIC values ranging from 15 to 19.6 µg/mL towards the Gram-negative bacteria and 51 µg/mL towards S. aureus; however, it was more effective against C. albicans and C. glabrata, with MIC values of about 6 µg/mL towards these fungal species. The toxicity of compounds 1 and 2 was assessed by evaluating the survival of the Caenorhabditis elegans model organism to concentrations of up to 100 µg/mL. The value of 50% lethality (LD50) could only be estimated as 73.2 µg/mL for compound 1 at 72 h, otherwise LD50 was >100 µg/mL for both compounds 1 and 2. These results indicate compounds 1 and 2 as novel silver complexes with interesting antimicrobial properties towards bacterial and fungal pathogens.

The mononuclear zinc(II) complex cis-[ZnL2(H2O)2] (1; L = 4-(pyridin-3-ylcarbamoyl)benzoate) was synthesized and characterized. By soaking crystals of 1 in a mixture of DMF-H2O solution containing a slight excess of Cu(NO3)2 × 3H2O a transmetalation reaction occurred affording the related copper(II) complex trans-[CuL2(H2O)2] (2). The structures of the compounds were authenticated by single crystal X-ray diffraction revealing, apart from a change in the isomerism, an alteration in the relative orientation of the chelating carboxylate groups and of the pyridine moieties. H-bond interactions stabilize both geometries and expand them into two-dimensional (2D) networks. The transmetalation was confirmed by SEM–EDS analysis. Moreover, the thermodynamic feasibility of the transmetalation is demonstrated by density-functional theory (DFT) studies. The catalytic activities of 1 and 2 for the oxidation of styrene and for the nitroaldol (Henry) C-C coupling reaction were investigated. The copper(II) compound 2 acts as heterogeneous catalyst for the microwave-assisted oxidation of styrene with aqueous hydrogen peroxide, yielding selectively (>99%) benzaldehyde up to 66% of conversion and with a turnover frequency (TOF) of 132 h−1. The zinc(II) complex 1 is the most active catalyst (up to 87% yield) towards the nitroaldol (Henry) coupling reaction between benzaldehyde and nitro-methane or -ethane to afford the corresponding β-nitro alcohols. The reaction of benzaldehyde with nitroethane in the presence of 1 produced 2-nitro-1-phenylpropanol in the syn and the anti diastereoisomeric forms, with a considerable higher selectivity towards the former (66:34).

C-scorpionate metal complexes, specifically, [NiCl2(tpm)]·3H2O, [CoCl2(tpm)]·3H2O and [PdCl2(tpm)] [tpm = hydrotris(1H-pyrazol-1-yl)methane], were effective in the N-formylation and N-methylation of amines using carbon dioxide, as carbon source, in the presence of sodium borohydride. Various parameters were studied, including reaction time, temperature, solvent volume, presence of additives, and catalyst amount. These parameters were found to have a significant impact on the selectivity of the product. [NiCl2(tpm)]·3H2O exhibited good conversion at 80 °C, but its selectivity towards formamide decreased with prolonged reaction time. Increasing the amount of [NiCl2(tpm)]·3H2O, the selectivity changed. [PdCl2(tpm)] showed different selectivity compared to [NiCl2(tpm)]·3H2O, while [CoCl2(tpm)]·3H2O presented poor results. Monitoring the reaction course by 1H NMR revealed the presence of an intermediate species that influenced product formation. These results highlight the versatility and catalytic potential of C-scorpionate metal complexes in the N-formylation/N-methylation of amines in the catalytic system (NaBH4/MeCN/CO2).

The conversion of renewable feedstocks into new added-value products is a current hot topic that includes the biodiesel industry. When converting vegetable oils into biodiesel, approximately 10% of glycerol byproduct is produced. Glycerol can be envisaged as a chemical platform due to its chemical versatility, as a scaffold or building block, in producing a wide range of added-value chemicals. Thus, the development of sustainable routes to obtain glycerol-based products is crucial and urgent. This certainly encompasses the use of raw carbonaceous materials from biomass as heterogeneous acid catalysts. Moreover, the integration of surface functional groups, such as sulfonic acid, in carbon-based solid materials, makes them low cost, exhibiting high catalytic activity with concomitant stability. This review summarizes the work developed by the scientific community, during the last 10 years, on the use of biochar catalysts for glycerol transformation.

The growing worldwide cancer incidence, coupled to the increasing occurrence of multidrug cancer resistance, requires a continuous effort towards the identification of new leads for cancer management. In this work, two C-scorpionate complexes, [FeCl2(κ3-Tpm)] (1) and [Co(κ3-TpmOH)2](NO3)2 (2), (Tpm = hydrotris(pyrazol-1-yl)methane and TpmOH = 2,2,2-tris(pyrazol-1-yl)ethanol), were studied as potential scaffolds for future anticancer drug development. Their cytotoxicity and cell migration inhibitory activity were analyzed, and an untargeted metabolomics approach was employed to elucidate the biological processes significantly affected by these two complexes, using two tumoral cell lines (B16 and HCT116) and a non-tumoral cell line (HaCaT). While [FeCl2(κ3-Tpm)] did not display a significant cytotoxicity, [Co(κ3-TpmOH)2](NO3)2 was particularly cytotoxic against the HCT116 cell line. While [Co(κ3-TpmOH)2](NO3)2 significantly inhibited cell migration in all tested cell lines, [FeCl2(κ3-Tpm)] displayed a mixed activity. From a metabolomics perspective, exposure to [FeCl2(κ3-Tpm)] was associated with changes in various metabolic pathways involving tyrosine, where iron-dependent enzymes are particularly relevant. On the other hand, [Co(κ3-TpmOH)2](NO3)2 was associated with dysregulation of cell adhesion and membrane structural pathways, suggesting that its antiproliferative and anti-migration properties could be due to changes in the overall cellular adhesion mechanisms.

Oxidovanadium(V) and dioxidovanadium(V) compounds, [VO(OEt)L] (1) and [Et3NH][VO2L] (2), were synthesized using an aroylhydrazone Schiff base (5-bromo-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L). They were characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), (1H and 51V) nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS) and single crystal X-ray diffraction analyses. Both complexes were immobilized on functionalized carbon nanotubes and activated carbon. The catalytic performances of 1 and 2, homogenous and anchored on the supports, were evaluated for the first time towards the MW-assisted peroxidative oxidation (with tert-butylhydroperoxide, TBHP) of cyclohexane under heterogeneous conditions. The immobilization of 1 and 2 on functionalized carbon materials improved the efficiency of catalytic oxidation and allowed the catalyst recyclability with a well-preserved catalytic activity.