Search Results (57)

Phenylene-based bis-oxamate polydentate ligands offer a unique opportunity for creating a large variety of coordination compounds, in which paramagnetic metal ions are strongly magnetically coupled. The employment of imino nitroxyl (IN) radicals as supplementary ligands confers numerous benefits, including the strong ferromagnetic interaction between Ni and IN. Furthermore, the chelating IN can act as a capping ligand, thereby impeding the formation of coordination polymers. In this study, we present the molecular and crystal structure and experimental and theoretical magnetic behavior of an exceptional neutral trinuclear complex [Ni(L³⁻)₂(IN)₃]∙5CH₃OH (1) (L is N,N′-1,3-phenylenebis-oxamic acid; IN is [4,4,5,5-tetramethyl-2-(6-methylpyridin-2-yl)-4,5-dihydro-1H-imidazol-1-yl]oxidanyl radical) with a cyclic triangular arrangement. Moreover, in this compound three Ni²⁺ ions are linked by the two bis-oxamate ligands playing a rare tritopic function due to an unprecedented triple deprotonation of the related meta-phenylene-bis(oxamic acid). The main evidence of such a deprotonation of the ligand is the neutrality of the cluster, since there are no anions or cations compensating for its charge in the crystals of the compound. Despite the presence of six possible magnetic couplings in the trinuclear cluster 1, its behavior was reproduced with a high degree of accuracy using a three-J model and ZFS, under the assumption that the three different Ni-IN interactions are equal to each other, whereas only two equivalent-in-value Ni-Ni interactions were taken into account, with the third one being equated to zero. Our study indicates the presence of two opposite-in-nature types of magnetic interactions within the triangular core. DFT and CASSCF/NEVPT2 calculations were completed to support the experimental magnetic data simulation. Full article

Background/Objectives: Recently, there has been great interest in metallopharmaceuticals as potential anticancer agents. In this context, presented studies aim to synthesize and evaluate of two copper(II) complexes derived from phthalazine- and imidazoline-based ligands against on three human cancer cell lines: cervix epithelial cell line (HeLa), breast epithelial-like adenocarcinoma (MCF-7), and triple–negative breast epithelial cancer cell line (MDA-MB-231), as well as non-tumorigenic cell line (HDFa). Moreover their antimicrobial, and antioxidant properties were assessed. Methods: The synthetized compounds—both free ligands L1, L2, L3 and copper(II) complexes C1 and C2—were characterized by elemental analysis, infrared spectroscopy. Additionally, a single-crystal X-ray diffraction studies we performed for free ligand L3 and its copper(II) complex C2. The stability of Cu(II)-complexes C1 and C2 was evaluated by UV-Vis spectroscopy. The cytotoxic potency of free ligands and their copper(II) complexes was estimated on HeLa, MCF-7, MDA-MB-231, as well as non-cancerous HDFa by use of an MTT assay after 48 h of incubation. Moreover, the antimicrobial activity of ligands L1 and L3 and their copper(II) complexes C1 and C2 was evaluated using reference strains of the following bacteria and yeasts: Staphylococcus aureus, Escherichia coli, and Candida albicans. The free radical scavenging properties of free ligands L1, L3 and the corresponding copper(II) complexes C1, C2 was tested with two colorimetric methods—ABTS, DPPH, and reduction ability assay (FRAP). Additionally, the ADME webtool was used to assess the drug-likeness of the synthesized compounds, as well as their physicochemical and pharmacokinetic properties. Results: Copper(II) complex C2 exhibited antitumor properties towards MDA-MB-231 compared with Cisplatin (cancer cell viability rate of 23.6% vs. 22.5%). At a concentration of 200 μg/mL, complexes C1 and C2 were less cytotoxic than the reference Cisplatin against a normal, non-cancerous skin fibroblast cell line (HDFa). According to in vitro tests, C2 reduced the viability of HeLa, MCF-7, and MDA-MB-231 cells by about 57.5–81.2%. It was evident that all compounds were devoid of antibacterial or antifungal activity. In vitro assays revealed that a moderate antiradical effect was observed for free ligand L1 containing phthalazin-1(2H)-imine in the ABTS radical scavenging assay (IC₅₀ = 23.63 µg/mL). Conclusions: The anticancer studies revealed that the most potent compound was copper(II) complex C2 bearing a phthalazin-1(2H)-one scaffold. None of the tested compounds showed antimicrobial or antifungal activity. This feature seems to be beneficial in terms of their potential uses as anticancer agents in the future. In vitro antiradical assays revealed that a moderate antioxidant effect was observed only for free ligand L1 containing phthalazin-1(2H)-imine. Full article

Carbendazim (CBZ) is a fungicide widely used on different crops, including soybeans, cereals, cotton, tobacco, peanuts, and sugar beet. Excessive use of this xenobiotic causes environmental deterioration and affects human health. Microbial metabolism is one of the most efficient ways of carbendazim elimination. In this work, Rhodococcus qingshengii RC1 and Rhodococcus erythropolis RC9 were isolated from a bacterial community growing in a biofilm reactor acclimated with microbiota from carbendazim-contaminated soil. Sequencing analysis of genomes of both strains revealed the presence of cbmA, the gene coding for the enzyme that hydrolyses carbendazim to produce 2-aminobenzimidazole (2-AB). The alternative gene for the first catabolic step (mheI) was detected by PCR in strain RC9 but not in RC1. Metabolomic analysis by HPLC and LC-MS showed that both strains have the ability to metabolize carbendazim. R. qingshengii RC1 converts carbendazim to 2-AB, the first degradation intermediary, while R. erythropolis RC9 metabolizes the fungicide to its mineralization, probably because R. qingshengii RC1 lacks the hdx gene coding for 2-AB hydroxylase. HRESIMS-MS/MS results indicate that R. erythropolis RC9 metabolizes carbendazim by cleavage of the benzene ring and subsequent formation of 5-formyl-2-hydroxy-4,5-dihydro-1H-imidazole-4-carboxylic acid (X2 C₅H₆N₂O₄). The presence of carbendazim metabolites in culture supernatants of strains RC9 and RC1 suggests that both strains contribute to the efficient degradation of carbendazim in nature. Full article

Polystyrene (PS) is widely used because of its transparency, mechanical strength, and ease of production. With rising health concerns, antibacterial PS is increasingly sought after, but few polymer-based antibacterial agents have been prepared to date. In this study, polystyrene was synthesized using a cationic radical initiator, 2,2′-azobis-[2-(1,3-dimethyl-4,5-dihydro-1H-imidazol-3-ium-2-yl)] propane triflate (ADIP), and evaluated as an antibacterial additive. The PS polymerized with ADIP (ADIP-PS) was prepared with number-average molecular weights (M_n) from 15,000 to 40,000. Further, blending 5–10% ADIP-PS with an M_n of 23,000 into general-purpose polystyrene (GPPS) provided antibacterial activity against Staphylococcus aureus while maintaining the transparency and strength of GPPS. Surface analysis revealed hydrophilic properties and exposed cationic groups, as confirmed by contact angle measurement and anionic dye titration, respectively. In addition, the antibacterial activity increased with higher cationic group concentrations, particularly at lower molecular weights. This method presents a promising approach to introducing antibacterial properties to PS products. Full article

A novel hybrid compound—2-(4,5-dihydro-1H-imidazol-2-yl)phthalazin-1(2H)-imine (5) was synthesized and converted into di-substituted sulfonamide derivatives 6a–o and phthalazine ring opening products—hydrazonomethylbenzonitriles 7a–m. The newly prepared compounds were characterized using elemental analyses, IR and NMR spectroscopy, as well as mass spectrometry. Single crystal X-ray diffraction data were collected for the representative compounds 5, 6c, 6e, 7g, and 7k. The antiproliferative activity of compound 5, sulfonyl derivatives 6a–o and benzonitriles 7a–m was evaluated on approximately sixty cell lines within nine tumor-type subpanels, including leukemia, lung, colon, CNS, melanoma, ovarian, renal, prostate, and breast. None of the tested compounds showed any activity against the cancer cell lines used. The antioxidant properties of all compounds were assessed using the DPPH, ABTS, and FRAP radical scavenging methods, as well as the β-carotene bleaching test. Antiradical tests revealed that among the investigated compounds, a moderate ABTS antiradical effect was observed for sulfonamide 6j (IC₅₀ = 52.77 µg/mL). Benzonitrile 7i bearing two chlorine atoms on a phenyl ring system showed activity in a β-carotene bleaching test (IC₅₀ = 86.21 µg/mL). Finally, the interaction AGE/RAGE in the presence of the selected phthalazinimines 6a, 6b, 6g, 6m, and hydrazonomethylbenzonitriles 7a, 7c–g, and 7i–k was determined by ELISA assay. A moderate inhibitory potency toward RAGE was found for hydrazonomethylbenzonitriles—7d with an electron-donating methoxy group (R = 3-CH₃O-C₆H₄) and 7f, 7k with an electron-withdrawing substituent (7f, R = 2-Cl-C₆H₄; 7k, R = 4-NO₂-C₆H₄). Full article

4-Acylpyrazolones are important ligands in analytical chemistry and technologies used for the separation and concentration of various metals. We have proposed a novel method for obtaining a material that consists of covalently immobilized functionalized ionic liquid on the surface of a mineral carrier featuring a coordination-active fragment of 4-acylpyrazolone. For its synthesis, we have introduced a strategy based on the quaternization of surface azolyl groups from 3-(1H-imidazol-1-yl)propyl silica with an alkylating reagent containing a 4-acylpyrazolone motif-4-(6-bromohexanoyl)-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one. This method of covalent immobilization preserves the 1,3-dioxo fragment, which ensures the effective binding of metal ions. The success of this functionalization has been confirmed by IR and ¹³C NMR spectroscopy data, as well as by thermogravimetric analysis. The overall functional capacity was found to be 0.3 mmol/g. The potential of the synthesized organomineral material to concentrate five rare earth elements (REEs) representing the cerium (Eu(III), Sm(III)) and yttrium groups (Gd(III), Dy(III), Er(III)) has been demonstrated. It was shown that during extraction from multicomponent systems, both under static and dynamic preconcentration conditions, there is a competitive influence of analytes, and their separation can be evaluated under dynamic conditions based on dynamic output curves and calculated distribution coefficients. It was shown that for systems where Kd > 1.8, quantitative separation can be performed in a dynamic mode of sorption under selected conditions. Full article

Because of their topical application in patients and meaningful UV/VIS absorptive properties, the degradation and potential toxicity under irradiation of diflunisal (DIF) and naphazoline (NAF) were studied. In addition, the impact of pH on their photostability was examined, showing the highest degradation of acidic DIF at pH 1 and 13 and the highest degradation of basic NAF at pH below 7. An LC–UV analysis and chemical tests showed the first-order kinetics for their degradation and generation of reactive oxygen species (ROS). A UPLC-HRMS/MS analysis allowed us to identify four degradants of DIF (from DD-1 to DD-4) and six degradants of NAF (from ND-1 to ND-6). When Toxtree software was used, a high class III of toxicity was observed for DD-2, DD-3, and DD-4, and for all the NAF degradants. Furthermore, the ND-2 product, i.e., 2-[(1-methylnaphthalen-2-yl)methyl]-4,5-dihydro-1H-imidazole, was shown to present medium mutagenic and high tumorigenic effects according to OSIRIS Property Explorer. In addition, two in vitro tests on BALB/c 3T3 mouse fibroblasts showed a phototoxic effect of DIF and NAF at the lowest concentrations tested, i.e., 5 µg/mL. Thus, our present results could be useful to design further phototoxicity studies for DIF and NAF to minimize the risk of phototoxicity due to their photodegradation. Full article

The genome—the source of life and platform of evolution—is continuously exposed to harmful factors, both extra- and intra-cellular. Their activity causes different types of DNA damage, with approximately 80 different types of lesions having been identified so far. In this paper, the influence of a clustered DNA damage site containing imidazolone (Iz) or oxazolone (Oz) and 7,8-dihydro-8-oxo-2′-deoxyguanosine (^OXOdG) on the charge transfer through the double helix as well as their electronic properties were investigated. To this end, the structures of oligo-Iz, d[A₁Iz₂A₃^OXOG₄A₅]*d[T₅C₄T₃C₂T₁], and oligo-Oz, d[A₁Oz₂A₃^OXOG₄A₅]*d[T₅C₄T₃C₂T₁], were optimized at the M06-2X/6-D95**//M06-2X/sto-3G level of theory in the aqueous phase using the ONIOM methodology; all the discussed energies were obtained at the M06-2X/6-31++G** level of theory. The non-equilibrated and equilibrated solvent–solute interactions were taken into consideration. The following results were found: (A) In all the discussed cases, ^OXOdG showed a higher predisposition to radical cation formation, and B) the excess electron migration toward Iz and Oz was preferred. However, in the case of oligo-Oz, the electron transfer from Oz₂ to complementary C₄ was noted during vertical to adiabatic anion relaxation, while for oligo-Iz, it was settled exclusively on the Iz₂ moiety. The above was reflected in the charge transfer rate constant, vertical/adiabatic ionization potential, and electron affinity energy values, as well as the charge and spin distribution. It can be postulated that imidazolone moiety formation within the CDL ds-oligo structure and its conversion to oxazolone can significantly influence the charge migration process, depending on the C2 carbon hybridization sp² or sp³. The above can confuse the single DNA damage recognition and removal processes, cause an increase in mutagenesis, and harm the effectiveness of anticancer therapy. Full article

Iron porphyrins are known to provide CH₄ as an eight-electron reduction product of CO₂ in a photochemical reaction. However, there are still some aspects of the reaction mechanism that remain unclear. In this study, we synthesized iron porphyrin dimers and carried out the photochemical CO₂ reduction reactions in N,N-dimethylacetamide (DMA) containing a photosensitizer in the presence of 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) as an electron donor. We found that, despite a low catalytic turnover number, CH₄ was produced only when these porphyrins were facing each other. The close proximity of the cyclic dimers, distinguishing them from a linear Fe porphyrin dimer and monomers, induced multi-electron CO₂ reduction, emphasizing the unique role of their structural arrangement in CH₄ formation. Full article

Bipartite entanglement is comprehensively investigated in the mononuclear molecular complex (Et₃NH)[Ni(hfac)₂L], where HL denotes 2-(2-hydroxy-3-methoxy-5-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl and hfacH stands for hexafluoroacetylacetone. From the magnetic point of view, the molecular compound (Et₃NH)[Ni(hfac)₂L] consists of an exchange-coupled spin-1 Ni²⁺ magnetic ion and a spin-$\frac{1}{2}$ nitronyl-nitroxide radical substituted nitrophenol. The nickel-radical molecular complex affords an experimental realization of a mixed spin-($\frac{1}{2}$, 1) Heisenberg dimer with a strong antiferromagnetic exchange coupling, J/$k_B$ = 505 K, and two distinct g-factors, g_Rad = 2.005 and g_Ni = 2.275. By adopting this set of magnetic parameters, we demonstrate that the Zeeman splitting of a quantum ferrimagnetic ground-state doublet due to a weak magnetic field may substantially reinforce the strength of bipartite entanglement at low temperatures. The molecular compound (Et₃NH)[Ni(hfac)₂L] maintains sufficiently strong thermal entanglement, even at room temperature, vanishing only above 546 K. Specifically, the thermal entanglement in the nickel-radical molecular complex retains approximately 40% of the maximum value, corresponding to perfectly entangled Bell states at room temperature, which implies that this magnetic compound provides a suitable platform of a molecular qubit with potential implications for room-temperature quantum computation and quantum information processing. Full article

The innovative synthesis of 3,8-dibromo-2,9-dinitro-5,6-dihydrodiimidazo [1,2-a:2′,1′-c]pyrazine and 3,9-dibromo-2,10-dinitro-6,7-dihydro-5H-diimidazo [1,2-a:2′,1′-c][1,4]diazepine is described in this study. The tricyclic fused molecular structures are formed by the respective amalgamation of piperazine and homopiperazine with the imidazole ring containing nitro. Compound 1 and 2 possess excellent high-density physical properties (ρ₁ = 2.49 g/cm³, ρ₂ = 2.35 g/cm³) due to the presence of a fused ring structure and Br atom. In addition to their high density, they have high decomposition temperatures (T_d > 290 °C) which means that they have excellent thermal stability and can be used as potential heat-resistant explosives. Low mechanical sensitivities (IS > 40 J, FS > 360 N) are observed. The twinning structure of 2 was resolved by X-ray diffraction. Non-covalent interaction analysis, Hirshfeld surfaces, 2D fingerprint plot, and Electrostatic potential analysis were used to understand the intramolecular interactions in relation to physicochemical properties. The unique structures of this type of compound provide new potential for the evolution of energetic materials. Full article

The metal–radical approach is a well-established synthetic way toward multi-spin systems that relies on the coordination of stable radical ligands with transition metal ions. The advantage offered by the use of paramagnetic ligands is that metal–radical magnetic exchange coupling is direct between the magnetic orbitals of the radical and metal ion. With the aim of further exploring this approach, crystals of four heterspin complexes, [M(hfac)₂L^F]₂ {M = Mn, Co, or Ni and hfac = hexafluoroacetylacetonate} and [Cu(hfac)₂L^F]_n, were obtained using a new fluorinated pyrazolyl-substituted nitronyl nitroxide radical, 4,4,5,5-tetramethyl-2-(5-fluoro-1-methyl-1H-pyrazol-4-yl)-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (L^F) as a ligand. The newly synthesized complexes were fully characterized, including X-ray crystallography and magnetometry. XRD analysis revealed that complexes [M(hfac)₂L^F]₂ have similar dimer structures in which a metal ion is in a six-coordinated environment with four O atoms from the two hfac ligands, one radical O atom, and one pyrazole N atom from ligand L^F. Nonetheless, the packing patterns of the complexes were found to be considerably different. In [Mn(hfac)₂L^F]₂, there are no magnetically important short contacts between manganese dimers. By contrast, in [Co(hfac)₂L^F]₂ and [Ni(hfac)₂L^F]₂, there are short contacts between non-coordinate O atoms of nitronyl nitroxide moieties. Magnetic behaviors of [M(hfac)₂L^F]₂ showed that the M ions and the directly coordinated radicals are strongly antiferromagnetically coupled (J_Mn-ON = −84.1 ± 1.5 cm⁻¹, J_Co-ON = −134.3 ± 2.6 cm⁻¹, and J_Ni-ON = −276.2 ± 2.1 cm⁻¹; $\widehat{H}=-2J{\widehat{\stackrel{⃑}{S}}}_{\mathrm{M}}{\widehat{\stackrel{⃑}{S}}}_{\mathrm{N}\mathrm{O}}$). Notably, the magnetization of [Mn(hfac)₂L^F]₂ having molecular structure proved to be accompanied by hysteresis. The [Cu(hfac)₂L^F]_n complex has a chain-polymer structure with alternating magnetic fragments: three spin exchange clusters {O_NO–Cu(II)–O_NO} and {Cu(II)} ions. Despite the direct coordination of radicals, its magnetic properties are weakly ferromagnetic (J_Cu-ON = 14.8 ± 0.3 cm⁻¹). Full article

In this study, we investigated the conformational abilities of n,n’-(Alkanediyl)-bis(2-phenyl-3,5-dihydro-4H-imidazol-4-one)s (1) to gain insight into their biological potential as a platform for the generation of various QACs. Among the conformers of 1, due to the flexibility of the polymethylene fragment, the phenyl rings can take on different mutual arrangements, while there is a clear tendency for the formation of π–π interactions. From the point of view of the reactivity to alkylating agents, a preliminary conclusion can be drawn about the favorable mutual arrangement of imidazolone rings located at a sufficient distance to carry out both mono- and bisalkylation to obtain bis-QAC. Full article

The reactions of alkenes with phenyl-N-triflylimino-λ³-iodane PhI=NTf (1) have been studied in different conditions. In methylene chloride, in the presence of N-halosuccinimides, the products of mono and bis-triflamidation were obtained. In MeCN, the product of bromotriflamidation (with NBS) with solvent interception or of bis-triflamidation (with NIS) is formed. The reaction with trans-stilbene in acetonitrile with NBS gave rise to cyclization to 2-methyl-4,5-diphenyl-1-triflyl-4,5-dihydro-1H-imidazole. In contrast, with NIS as an oxidant, both in CH₂Cl₂ and MeCN, the major product was 2,3-diphenyl-1-triflylaziridine formed in good yield. With NBS, aziridine is also formed but as a minor product, the major one being a mixture of diastereomers of the product of bromotriflamidation. The reaction of compound 1 with vinylcyclohexane in methylene chloride affords the mixtures of regioisomers of the products of halotriflamidation, whereas in acetonitrile, the products of solvent interception and cyclization to the imidazoline are formed. A mechanism explaining the formation of all isolated products is proposed. Full article

Enantiomerically pure (S)-1-phenylethan-1-amine has been applied in Mannich-type condensation between formaldehyde and naphthalenediols leading to the synthesis of chiral bis-dihydro[1,3]naphthoxazines in excellent yields. Salen-type structures have been synthesized, applying R,R- or S,S-cyclohexane-1,2-diamines in condensation with formaldehyde and naphthalene-2-ol. The obtained chiral imidazolidine derivatives of the type 1,1′-(((3a,7a)-hexahydro-1H-benzo[d]imidazole-1,3(2H)diyl)bis(methylene))bis(naphthalen-2-ol) were evaluated as pre-catalysts for the addition of diethyl zinc to aldehydes. The structures of the newly synthesized compounds were elucidated using ¹D and ²D NMR experiments (COSY, HMBC, HSQS), elemental analysis, mass spectrometry (HRMS spectra) and single-crystal X-ray diffraction (SCXRD). The products were further characterized with powder X-ray diffraction (PXRD) and thermal analysis (DSC). Full article