ChemPlusChem最新文献

The multifluoro-modified aniline, 2,6-bis[bis(4-fluorophenyl)methyl]-4-trifluoromethoxy-phenylamine, is meticulously synthesized and utilized to form a series of bis(imino)pyridine derivatives. These derivatives react with cobalt chloride to give six bis(imino)pyridylcobalt (II) complexes (alkyl: 2,6-dimethyl Co1; 2,6-diethyl Co2; 2,6-diisopropyl Co3; 2,4,6-trimethyl Co4; 2,6-diethyl-4-methyl Co5; 2,6-bis[bis(4-fluorophenyl)methyl]-4-trifluoromethoxy Co6). High activity and good thermal stability in ethylene polymerization are achieved by these cobalt complexes in the presence of MAO or MMAO. Notably, superior polymerization results are observed in n-hexane compared to toluene with peak activity reaching 1.55 × 107 g (PE) mol-1 (Co) h-1 at 70 oC in n-hexane. Moreover, the resulting polyethylenes are highly linear, featuring vinyl terminal group, and exhibit a wide range of molecular weights (Mw: 22.5‒285 kg mol-1) along with high melting points (Tm > 127.3 oC).

Copper-based pigments, such as verdigris, have caused severe damage to many important historical documents, and their preservation remains a significant concern for paper conservators and researchers. This study re-evaluates the efficacy of two promising antioxidants, tetrabutylammonium bromide (TBABr) and benzotriazole (BTA), as stabilization agents for paper documents containing verdigris pigment. To assess the stability of the mock-up papers, various parameters were measured during accelerated degradation, including colour, molecular weight (Mw), and pH value. Size exclusion chromatography measurements of Mw confirmed that TBABr provided superior stabilization compared to BTA. Additionally, the total colour change was slightly more pronounced in the samples treated with BTA compared to those treated with TBABr. However, during degradation, some paper samples containing thicker application of pigment exhibited significant black and brown spots, regardless of treatment (untreated, treated with BTA, or TBABr). X-ray photoelectron spectroscopy confirmed the presence of both Cu(I) and Cu(II) oxidation states in all samples, with a higher Cu(II) content on the surface of TBABr treated samples compared to those treated with BTA. This may indicate differences in the mechanisms of degradation. Raman spectroscopy identified the spots on both untreated and TBABr-treated samples as copper(II) oxide.

The first examples of Ru(II) h6-arene (benzene and p-cymene) complexes containing a bidentate triazolylidene-triazolide ligand have been prepared and fully characterized. Their antiproliferative effect has been investigated against tumour cells A2780 (ovarian carcinoma), HCT116 (colorectal carcinoma), and HCT116dox (colorectal carcinoma resistant to doxorubicin), and in human dermal fibroblasts. The Ru complex bearing the p-cymene arene group exhibited a stronger antiproliferative effect across all tested cell lines, while the benzene-containing complex displayed higher selectivity toward tumor cells. Both complexes induced apoptosis, likely through ROS production (in the benzene complex), and inhibited tumorigenic processes, including cell migration and angiogenesis. In zebrafish models, they showed strong selectivity for cancer cells with minimal toxicity to healthy cells, effectively reducing the proliferation of HCT116 colorectal cancer cells. This study provides the first in vivo evidence of the anticancer potential of Ru triazolylidenes in zebrafish models.

Wastewater treatment plants (WWTPs) currently represent one of the main sources for microplastics (MPs) and other emerging contaminants entering the environment. Coagulation is a longstanding and cost-effective process designed to enhance the removal of colloidal particles and proved to be efficient in the abatement of MPs. The present study investigates the feasibility of a progressive replacement of ferric chloride (FeCl3) with chitosan (CT) and sodium alginate (SA), starting from their use as coagulant aids. Coagulations tests were carried out to assess the performance of FeCl3-CT and FeCl3-SA systems in the removal of polystyrene (PS) microbeads, polyethylene (PE) and polyethylene terephthalate (PET) fragments with sizes lower than 500 μm. Results from experiments have shown that both CT and SA are useful to enhance the removal performance of conventional coagulation by improving the settling characteristics of flocs. The use of CT allows a reduction of coagulant dosage for removing PS and PE particles, while it turned out to be detrimental for the removal of PET fragments. Instead, SA at a concentration of 0.2 mg L-1 proved to be useful both to achieve higher removal rate at a medium dosage of coagulant and to improve the efficiency of the process at lower dosages.

A single-molecule with a large transistor (SiMoT) array is used to explore the impact of data preprocessing on electronic biosensor outcomes. Cyst fluid and plasma samples from 37 patients with pancreatic precursor cyst lesions are analyzed. New strategies to mitigate these effects are provided, ensuring that data interpretation remains accurate and reflective of the underlying biochemical information in the samples. More details can be found in the Research Article by Luisa Torsi, Eleonora Macchia, and co-workers (DOI: 10.1002/cplu.202400520).

The front cover shows the artificial compartments constructed using liposomes, polymersomes, proteins, DNA nanostructures, and hybrid materials. Enzymes have been incorporated, assembled, or spatially organized into the membrane or membraneless compartments to efficiently carry out the enzymatic reactions or metabolic pathways and to understand the chemistry behind the compartment function. These compartments can be the building blocks to construct the artificial organelles with the target functions. More details can be found in the Review by Takashi Morii and co-workers (DOI: 10.1002/cplu.202400483).

The self-assembly reaction of 2-benzylaminoethanol (Hbae) with CuCl2 or Cu(NO3)2 leads to the formation of binuclear [Cu2(bae)2(Cl)2] (1) and [Cu2(Hbae)2(bae)2](NO3)2 (2) complexes, while the trinuclear [Cu3(Hbae)2(bae)2(dmba)2](NO3)2 (3) compound was obtained using the auxiliar bulky substituted 2,2-dimethylbutyric acid (Hdmba). All three compounds act as catalysts for the aerobic oxidation of 2-aminophenol to the phenoxazinone chromophore (phenoxazinone synthase-like activity) with the maximum reaction rates up to 2.3 × 10-8 M s-1. The substrate scope involves methyl-, nitro- and chloro-substituted 2-aminophenols, disclosing the negligible activity of nitro-derivatives, while the 6-amino-m-cresol substrate shows the highest activity with the initial reaction rate of 5.8 × 10-8 M s-1. The mechanism of the rate-limiting reaction step (copper-catalysed formation of 2-aminophenoxyl radicals) was investigated at the DFT level. The combined DFT and CASSCF studies of the copper superoxo CuII-OO· radical species as possible unconventional reaction intermediates resulted in a rational mechanism of H-atom abstraction, where the activation energies follow the experimental reactivity of substituted 2-aminophenols. The TDDFT and STEOM-DLPNO-CCSD theoretical calculations of the absorption spectra of substrates, phenoxazinone chromophores and putative polynuclear species containing 2-aminophenoxo ligand are reported.

In this study, a computational design of a new type of donor-acceptor mixed stacking cocrystals is introduced. Our approach involves functionalizing trisilasumanene frameworks with electron-donating groups (-CH3, -OH, -NH2) and electron-withdrawing groups (-F, -CN), and then stacking donors and acceptors alternatively while connecting them either by sp3- and sp-carbon chains. Using the B3LYP-D3/6-31+G(d) level of theory, we demonstrate that these covalently bonded cocrystals can overcome the issue of thermal and mechanical instabilities observed in the non-covalently mixed stacking. Furthermore, modifying donor and acceptor groups can vary the bandgaps, approximated by the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) gaps, from 1.50 to 3.50 eV. The results also predict the covalently bonded mixed stacking cocrystals having much larger conductance via Yoshizawa model. In addition, variations in bridge lengths were found to have a small effect on the HOMO-LUMO gaps but allow for a new control parameter regarding the porosity of the materials. These results encourage experimental explorations.

Enzyme immobilization is regarded as a key factor for their effective utilization in various fields such as biofuel production, wastewater treatment, and biosensors. Designing new electrodes with biocompatible support matrices is essential to improve the stability in bioelectrocatalysis. Modified carbon felt electrodes were prepared and tested as bioelectrocatalyst under mild conditions - aqueous media at room temperature and basically neutral pH. Co-immobilization of dehydrogenase enzymes and neutral red (NR) dye at carbon felt electrodes was successfully achieved during electropolymerization of pyrrole in a facile one-step approach. Neutral red was incorporated to operate as a redox mediator supporting efficient electron transfer to the enzymes' active sites. Electrodes modified with alcohol dehydrogenase (ADH) have been employed to reduce acetaldehyde to ethanol in a chronoamperometic setting with Faradaic efficiency (FE) of up to 33%. By incorporating the cascade reaction with three enzymes - ADH, formate dehydrogenase, and formaldehyde dehydrogenase - an electroreduction sequence could be established to produce methanol from CO2 reaching a FE of 10%. The proposed approach shows good stability. Together with the simple implementation and application, this process is promising for employment in enzymatic electrocatalysis.

The development of inorganic metal and metal oxide nanoparticles (MNPs) has attracted significant attention in  biomedical and biotechnological fields. An emerging field in this context is the use of MNPs  in reproduction biology. Here, we review the development of MNPs in the field of reproduction  by focusing on their interactions with highly delicate and specialized germ cells like spermatozoa and oocytes as well as developing embryos. By their unique physicochemical properties, MNPs are good candidates for targeted imaging and delivery of biofunctional molecules  to the specific sites of the gametes and reproductive cells. Furthermore, functionalized MNPs can serve as transfection vectors for the generation of transgenic animals by sperm-mediated gene transfer (SMGT) in artificial insemination or in vitro fertilization. In addition, MNPs have shown great promise in application fields such as semen collection, nano-purification, cryopreservation, and sex sorting of sperm in the livestock industry. The article includes an in-depth discussion on the uptake, translocation mechanism, and bioresponse of the MNPs to reproduction-relevant sites on the clinical, cellular, and molecular levels. Based on these promising achievements, the current challenges and prospects of the development of these functionalized MNPs for clinical research in conjunction with the reproductive system will be discussed.