Search Results (25)

Although spontaneous or complexation-induced reductions of Cu^II to Cu^I have occasionally been observed, controlling these processes remains a challenge. Herein, we report the synthesis of Cu^I complexes via the complexation-induced reduction of Cu^II complexes with pyridine-containing N₄ Schiff-base ligand L incorporating a biphenyl unit (L = N,N’-([1,1′-biphenyl]-2,2′-diyl)bis(1-(6-methylpyridin-2-yl)methanimine)). Such a reduction has not yet been observed in previously reported Cu^II complexes with pyridine-containing N₄ Schiff-base ligands, strongly suggesting that the torsional distortion of the ligand framework induced by the biphenyl moiety effectively promotes the complexation-induced reduction of Cu^II to Cu^I. The Cu^I complexes were thoroughly characterized by ¹H NMR spectroscopy, UV–vis–NIR spectroscopy, and single-crystal X-ray diffraction analyses. The [Cu^I(L)]⁺ complex undergoes a reversible redox process with its oxidized species, which was identified as a Cu^II complex based on spectroelectrochemical measurements and theoretical calculations. Full article

Here we presented the synthesis of two groups of heterocyclic benzimidazole derivatives—methanimines 4a–c and hydrazones 6a–c. In vitro biological activity screening of the compounds was performed on isolated encapsulated muscle larvae of Trichinella spiralis. All tested compounds showed higher efficacy than albendazole, with compound 4a demonstrating activity comparable to ivermectin. Structure–activity relationship (SAR) analysis revealed that methanimines 4a–c, containing a thiophene moiety, were more effective than their hydrazone counterparts, highlighting the beneficial synergy between benzimidazole and thiophene pharmacophores. However, replacing the -N=CH- linker in compound 4a with -NH-N=CH- (as in compound 6a) led to a 23% reduction in activity, suggesting that methaniamines possess superior larvicidal potency under equivalent structural conditions. The ability of the studied compounds to interfere with the tubulin polymerization was studied spectrophotometrically on purified porcine brain. Of note, the tested benzimidazoles 4a–b and 6a–b had no discernible effect on tubulin polymerization. An in silico study of the physicochemical and pharmacokinetic characteristics of the novel synthesized heterocyclic benzimidazoles showed that they were characterized by a significant degree of drug-likeness and optimal properties for antineurotrichinellosis agents. Full article

Due to the lack of UV-protective properties for cotton textiles and the potential of cotton textiles to cause microbes to their users, we synthesized benzimidazole Schiff base derivative (BZI) namely N-((1H-benzo[d]imidazol-2-yl)methyl)-1-(4-fluorophenyl)methanimine and their V(III), Fe(III), Co(II), Ni(II), and Cu(II) complexes as UV protection and antimicrobial agents for cotton textile. Several techniques investigated these compounds: ¹H, ¹³C NMR, IR, UV–Vis, elemental analysis, DTA, and TGA. The Schiff base ligand behaved as a bidentate ligand. The prepared ligand and its complexes are used to treat the cotton fabrics (CFs) by immersing the fabric in the solution of the samples under ultrasonic. The treated cotton fabrics were investigated using IR and SEM-EDX analysis. The UPF values of the treated cotton fabric were obtained. The results showed that the cotton fabric treated with Fe(III) and Cu(II) complexes had excellent UV protection with UPF values of 50+. The disc diffusion method evaluated the treated cotton fabric’s antimicrobial activity. The antifungal activities of the treated CFs demonstrated that the Co(II)-BZI-CF was active on C. albicans with an inhibition zone of 12 mm, while the other samples were inactive on C. albicans and A. flavus. The V(III)-BZI-CF and Fe(III)-BZI-CF had no activity against S. aureus and E. coli bacteria while the other samples gave an inhibition zone of between 10 to 17 mm. Unlike previous studies that primarily focused on either UV protection or antimicrobial properties of metal complexes separately, this research integrates both functionalities by synthesizing benzimidazole Schiff base metal complexes and applying them to cotton textiles, demonstrating enhanced UV protection and selective antimicrobial activity. Full article

The title compound (1) was obtained within a project aimed at synthesizing inhibitors of the human enzyme lactate dehydrogenase A (hLDHA). Compound 1 was synthesized by Suzuki cross-coupling of (E)-1-(4-bromophenyl)-N-(4-methoxyphenyl)methanimine (2a) or (E)-1-(4-iodophenyl)-N-(4-methoxyphenyl)methanimine (2b) with 4-(trifluoromethyl)phenylboronic acid (3) using Pd(PPh₃)₄ as a catalyst in 86% and 87% yields, respectively. Halo-imines 2a and 2b were previously obtained by condensation reaction between p-anisidine (4) and 4-bromo-benzaldehyde (5a) or 4-iodo-benzaldehyde (5b), respectively. The structure of compound 1 was established by 1D and 2D NMR spectroscopy, infrared and ultraviolet spectroscopies, and high-resolution mass spectrometry. Full article

Background: Breast cancer influences more than 2 million women worldwide annually. Since apoptotic dysregulation is a cancer hallmark, targeting apoptotic regulators encompasses strategic drug development for cancer therapy. One such class of apoptotic regulators is inhibitors of apoptosis proteins (IAP) which are a class of E3 ubiquitin ligases that actively function to support cancer growth and survival. Methods: The current study reports design, synthesis, docking analysis (based on binding to IAP-BIR3 domains), anti-proliferative and anti-tumor potential of the azomethine derivative, 1-(4-chlorophenyl)-N-(4-ethoxyphenyl)methanimine (BCS3) on breast cancer (in vitro and in vivo) and its possible mechanisms of action. Results: Strong selective cytotoxic activity was observed in MDA-MB-231, MCF-7, and MDA-MB-468 breast cancer cell lines that exhibited IC50 values, 1.554 µM, 5.979 µM, and 6.462 µM, respectively, without affecting normal breast cells, MCF-10A. For the evaluation of the cytotoxic potential of BCS3, immunofluorescence, immunoblotting, and FACS (apoptosis and cell cycle) analyses were conducted. BCS3 antagonized IAPs, thereby causing MDM2-p53 and Bcl-2-Caspase-mediated intrinsic and extrinsic apoptosis. It also modulated p53 expression causing p21-CDK1/cyclin B1-mediated cell cycle arrest at S and G2/M phases. The in vitro findings were consistent with in vivo findings as observed by reduced tumor volume and apoptosis initiation (TUNEL assay) by IAP downregulation. BCS3 also produced potent synergistic effects with doxorubicin on tumor inhibition. Conclusions: Having witnessed the profound anti-proliferative potential of BCS3, the possible adverse effects related to anti-cancer therapy were examined following OECD 407 guidelines which confirmed its systemic safety profile and well tolerability. The results indicate the promising effect of BCS3 as an IAP antagonist for breast cancer therapy with fewer adverse effects. Full article

A new tridentate Cu²⁺ complex based on (E)-1-(pyridin-2-yl)-N-(quinolin-8-yl)methanimine (PQM) was generated and characterized to support the activation of diazo compounds for the formation of new C–N bonds. This neutral Schiff base ligand was structurally characterized to coordinate with copper(II) in an equatorial fashion, yielding a distorted octahedral complex. Upon characterization, this copper(II) complex was used to catalyze an efficient and cost-effective protocol for C–N bond formation between N-nucleophiles and copper carbene complexes arising from the activation of diazo carbonyl compounds. A substrate scope of approximately 15 different amine-based substrates was screened, yielding 2° or 3° amine products with acceptable to good yields under mild reaction conditions. Reactivity towards phenol and thiophenol were also screened, showing relatively weak C–O or C–S bond formation under optimized conditions. Full article

The ligand named 1-(3-chlorophenyl)-N-(pyridine-2-yl)methanimine Schiff base was obtained with the method of mixing 2-amino pyridine with 3-chloro benzaldehyde in methanol as an initial material. Transition metals, like Cu(II), were added to the prepared ligand as a dopant. The molecular structure was characterized by elemental analysis, electronic methods (UV-Visible), Vibrational methods (FT-IR), and ¹H NMR spectroscopy. The catalytic activities of the complex were studied using Claisen–Schmidt condensation for the synthesis of chalcone derivatives employed using three different catalysts by an ultrasonication method. The results reveal that the Cu(II) complex showed remarkable catalytic activity and good yield compared to the other catalysts. Full article

A series of Schiff base derivatives, namely N-(4-methoxyphenyl)-1-(1-methylbenzimidazol-2-yl)methanimine (L¹), 4-methoxy-N-[(1-methylbenzimidazol-2-yl)methyl]aniline (L²), and 2-[(E)-(1-propylbenzimidazol-2-yl)iminomethyl]phenol (L³), were synthesized. These compounds feature different linker groups, including –CH=N–, –CH₂–NH–, and –N=CH–, respectively. During the process of zinc(II) and cadmium(II) complexation in the presence of the closo-dodecaborate [B₁₂H₁₂]^2– anion, it was observed that ligand L³ underwent degradation. Consequently, two compounds were isolated, [Zn(Bz-NH₂)₂(CH₃COO)₂] and (HBz-NH₂)₂[B₁₂H₁₂]∙2CH₃CN, both containing 1-propyl-2-aminobenzimidazole (Bz-NH₂), which is a degraded fragment of the ligand. Several new zinc(II) and cadmium(II) coordination compounds were synthesized and characterized using various physicochemical analysis methods, including elemental analysis, IR, and UV spectroscopy. Additionally, X-ray diffraction and Hirshfeld surface analysis were performed for compounds [Cd(L²)₂(CH₃CN)(H₂O)][B₁₂H₁₂], [Zn(Bz-NH₂)₂(CH₃COO)₂], and (HBz-NH₂)₂[B₁₂H₁₂]∙2CH₃CN, as well as for ligand L². Full article

This study focuses on the synthesis, characterization, and properties of a yellowish, prism-shaped ligand, N,N′-(naphthalene-1,5-diyl) bis(1-(pyridin-2-yl) methanimine). The ligand was synthesized through refluxing 1,5-diaminonaphthalene and pyridine-2-carbaldehyde in extra-pure ethanol, employing X-ray diffraction on single crystal. The crystal is structured with two pyridylimine-binding units linked to a naphthalene. The crystal has a P2₁/c space group in a monoclinic system. The structure was confirmed through an infrared examination. Computational spectroscopy and theoretical methods were used to investigate the ligand HOMO, LUMO, and charge distribution. Additionally, a Hirshfeld analysis was performed to investigate noncovalent interactions in the crystalline form. The results showed that dispersion forces (H···H) were the primary factor contributing to the arrangement of the ligand molecule, accounting for 45.3% of the total interactions in the absence of hydrogen bonding. Overall, this study provides valuable insights into the synthesis, characterization, and properties of this unique ligand. Full article

The imino pyridine Schiff base cobalt(II) and nickel(II) complexes (C1 and C2) and their functionalised γ-Fe₃O₄ counterparts (Fe₃O₄@C1 and Fe₃O₄@C2) were synthesised and characterised using IR, elemental analysis, and ESI-MS for C1 and C2, and single crystal X-ray diffraction for C1, while the functionalised materials Fe₃O₄@C1 and Fe₃O₄@C2 were characterized using IR, XRD, SEM, TEM, EDS, ICP-OES, XPS and TGA. Complexes C1, C2 and the functionalised materials Fe₃O₄@C1 and Fe₃O₄@C2 were tested as catalysts for the selective transfer hydrogenation of cinnamaldehyde and all four pre-catalysts showed excellent catalytic activity. Complexes C1 and C2 acted as homogeneous catalysts with high selectivity towards the formation of hydrocinnamaldehyde (88.7% and 92.6%, respectively) while Fe₃O₄@C1 and Fe₃O₄@C2 acted as heterogeneous catalysts with high selectivity towards cinnamyl alcohol (89.7% and 87.7%, respectively). Through in silico studies of the adsorption energies, we were able to account for the different products formed using the homogeneous and the heterogeneous catalysts which we attribute to the preferred interaction of the C=C moiety in the substrate with the Ni centre in C2 (−0.79 eV) rather than the C=O (−0.58 eV). Full article

A novel approach was carried to prepare trans-CuCl₂L₂ complex with the ligand L, (E)-(4-chlorophenyl)-N-(3-phenyl-4H-1,2,4-triazol-4-yl)methanimine which was formed in situ during the reaction of CuCl₂ with 4-(4-chlorobenzylideneamino)-5-phenyl-2H-1,2,4-triazole-3(4H)-thione. The synthesized compounds were characterized by applying various spectroscopic techniques. The crystal structure of the complex was unambiguously determined using X-ray analysis indicating square planar geometry. Intermolecular H-bonds govern the supramolecular structure of the copper complex. Aromatic rings are stacked in an offset packing due to occurrence of π–π interactions. The structure is further corroborated with a detailed computational investigation. A thione–thiol tautomerism for the triazole compound was also studied. The Schiff base 1,2,4-triazole copper chloride complex is expected to have high anticancer activity. Full article

Nowadays, most stroke patients are treated exclusively with recombinant tissue plasminogen activator, a drug with serious side effects and limited therapeutic window. For this reason, and because of the known effects of oxidative stress on stroke, a more tolerable and efficient therapy for stroke is being sought that focuses on the control and scavenging of highly toxic reactive oxygen species by appropriate small molecules, such as nitrones with antioxidant properties. In this context, herein we report here the synthesis, antioxidant, and neuroprotective properties of twelve novel polyfunctionalized α-phenyl-tert-butyl(benzyl)nitrones. The antioxidant capacity of these nitrones was investigated by various assays, including the inhibition of lipid peroxidation induced by AAPH, hydroxyl radical scavenging assay, ABTS⁺-decoloration assay, DPPH scavenging assay, and inhibition of soybean lipoxygenase. The inhibitory effect on monoamine oxidases and cholinesterases and inhibition of β-amyloid aggregation were also investigated. As a result, (Z)-N-benzyl-1-(2-(3-(piperidin-1-yl)propoxy)phenyl)methanimine oxide (5) was found to be one of the most potent antioxidants, with high ABTS⁺ scavenging activity (19%), and potent lipoxygenase inhibitory capacity (IC₅₀ = 10 µM), selectively inhibiting butyrylcholinesterase (IC₅₀ = 3.46 ± 0.27 µM), and exhibited neuroprotective profile against the neurotoxicant okadaic acid in a neuronal damage model. Overall, these results pave the way for the further in-depth analysis of the neuroprotection of nitrone 5 in in vitro and in vivo models of stroke and possibly other neurodegenerative diseases in which oxidative stress is identified as a critical player. Full article

Aiming at constructing photoresponsive spin crossover (SCO) behavior, herein we designed a new ligand Abtz (Abtz = (E)-N-(4-((E)-phenyldiazenyl)phenyl)-1-(thiazol-4-yl)methanimine) which was decorated by a photochromic azobenzene group. Based on this photochromic ligand, a mononuclear Fe(II) SCO molecule [Fe(Abtz)₃](BF₄)₂·(EAC)₂ (1, EAC = ethyl acetate) was successfully synthesized and showed a complete one-step SCO behavior. Under continuous UV light and blue-light exposure, the cis–trans photoisomerization of both ligand Abtz and compound 1 in the liquid phase was confirmed through UV–Vis spectra. Moreover, the ¹H-NMR spectra of Abtz reveal a trans–cis conversion ratio of 37%. Although the UV–Vis spectra reveal the photochromic behavior for 1 in the solution phase, the SCO behavior in the liquid state is absent according to the variable-temperature Evans method, suggesting the possible decomposition. Moreover, in the solid state, the cis–trans photoisomerization of both Abtz and 1 was not observed, due to the steric hindrance. Full article

A novel series of 1-aryl-N-[4-phenyl-5-(arylazo)thiazol-2-yl)methanimines has been synthesized via the condensation of 2-amino-4-phenyl-5-arylazothiazole with various aromatic aldehydes. The synthesized imines were characterized by spectroscopic techniques, namely ¹H and ¹³C-NMR, FTIR, MS, and Elemental Analysis. A molecular comparative docking study for 3a–f was calculated, with reference to two approved drugs, Molnupiravir and Remdesivir, using 7BQY (M^pro; PDB code 7BQY; resolution: 1.7 A°) under identical conditions. The binding scores against 7BQY were in the range of −7.7 to −8.7 kcal/mol for 3a–f. The high scores of the compounds indicated an enhanced binding affinity of the molecules to the receptor. This is due to the hydrophobic interactions and multi-hydrogen bonds between 3a–f ligands and the receptor’s active amino acid residues. The main aim of using in silco molecular docking was to rank 3a–f with respect to the approved drugs, Molnupiravir and Remdesivir, using free energy methods as greener pastures. A further interesting comparison presented the laydown of the ligands before and after molecular docking. These results and other supporting statistical analyses suggested that ligands 3a–f deserve further investigation in the context of potential therapeutic agents for COVID-19. Free-cost, PASS, SwissADME, and Way2drug were used in this research paper to determine the possible biological activities and cytotoxicity of 3a–f. Full article