Applied Organometallic Chemistry最新文献

Three Co(II) complexes of terephthalate anion containing 1,10-phenanthroline (phen) or 2,2′-bipyridine (2,2′-bipy), are prepared. The structures of dimeric [Co₂(H₂O)₄(μ-H₂O)₂(phen)₂]⁴⁺·2(C₈H₄O₄²⁻), 1, and the polymeric [Co₂(H₂O)₂(phen)₂(μ-C₈H₄O₄)₂]_n, 2, complexes were confirmed by single crystal structure determination. Both complexes have CoN₂O₄ core in a distorted octahedral arrangement. Extensive hydrogen bonding and π–π stacking interactions consolidate 3-D structures in 1 and 2. Complex 3, [Co(μ-C₈H₄O₄)(2,2′-bipy)]_n, was previously reported. It has CoN₂O₄ core in a distorted trigonal prismatic environment. Complexes 1, 2 and 3 exhibited good inhibition efficiencies for corrosion of carbon steel in 0.25-M sulfuric acid solution. The order of corrosion inhibiting effect of the complexes was 2 (94.6%) > 1 (90.5%) > 3 (79.5%). The increase in R_p value and the decrease in C_dl were in parallel with the increase in the concentration of complexes. Tafel plot indicated that complex 1 behaved as a cathodic-type corrosion inhibitor, whereas complexes 2 and 3 as anodic inhibitors for C-steel in sulfuric acid medium. Weight loss measurement of steel samples in 1-M HCl showed more inhibition of corrosion by complexes 1 and 2 than by complex 3. The adsorption mechanism of inhibitors on C-steel followed Langmuir isotherm. The free energy changes indicated comprehensive physical and chemical adsorption for the three complexes on the surface of the C-steel. SEM analysis of steel samples in 1-M HCl proved the efficiency of complexes in retarding corrosion as the steel surface showed smoothness compared to the blank. Quantum chemical DFT study declared that the highest corrosion inhibition efficiency is observed for complex 2, which was strongly supported by the electrochemical anticorrosion studies. The results of the TGA analysis support the X-ray crystal structures of the complexes.

A new complex of type [Nd (HL) (NO₃)₂] has been synthesized with a Schiff base ligand H₂L derived from 2-hydroxy-3-methoxybenzaldehyde and L-histidine. The structure of the synthesized complex was established using elemental analysis, molar conductivities, FT-IR, ¹HNMR, SEM, and x-ray diffraction (XRD) spectroscopy. FT-IR data revealed that H₂L acts as a tetradentate ligand through the carboxylic acid, azomethine nitrogen, methoxy oxygen, and hydroxyl groups. Based on the electronic spectra, an octahedral configuration was hypothesized for the complex. The TGA method was employed to study the thermal behavior of ligand and its complex, and thermodynamic parameters were determined using Coats–Redfern equations. The XRD analysis revealed that the synthesized compounds possess nanoscale dimensions, with their crystallinity significantly enhanced by the coordination of the Nd(III) ion with H₂L. DFT calculations were performed to optimize the geometry of the proposed structures, indicating improved thermodynamic and electronic stabilities. The reduced HOMO–LUMO gap in the Nd(III) complex further highlights its remarkable conductive and electronic properties. The surface morphology of the Nd(III) complex was analyzed using SEM to investigate its structural characteristics. The SEM images reveal a variety of particle shapes, including elongated, prismatic, and irregular blocky particles with sharp edges, suggesting a crystalline nature. The ligand and its Nd(III) complex were evaluated for their anticancer activity against prostate carcinoma, breast carcinoma, and lung carcinoma cell lines. The inhibition rate of Nd(III) complex was 92.81%, 93.25%, and 94.58%, respectively. The results demonstrated that the Nd(III) complex exhibited significantly enhanced anticancer activity compared to the ligand alone, likely due to its improved structural and electronic properties. These findings suggest that the Nd(III) complex holds promise as a potent anticancer agent.

The complexes of [Zn (DAP)(SA)] (1) and [Zn (bpy)(DAP)]Cl₂ (2) (where DAP is 3,4-diaminobenzophenone, SA is a dianion of salicylate, and bpy is 2,2′-bipyridine) were synthesized and characterized using various techniques such as ¹H NMR, ESI-Mass, ¹³C NMR, FT-IR, thermal gravimetric analysis (TGA), and UV–Vis. The formation of these complexes was supported by theoretical DFT approach. It reveals that these complexes have tetrahedral geometry. The interaction of these complexes with CT-DNA was studied by different methods. The UV–Vis titration revealed a bathochromic shift and significant hypochromicity at 260 nm for the absorption band of CT-DNA in the presence of these complexes. The studies in this work showed that the intercalative interaction between these complexes and CT-DNA is not the main or strongest mode, but other modes such as groove binding play role in their interactions. The achieved results from viscosity and electrochemical measurement confirmed this finding. The fluorescence studies showed that the proposed mechanism of fluorescence quenching for both complexes is static quenching. The thermodynamic parameters (ΔH° and ΔS°) revealed that the interaction of complex (1) with DNA occurs through hydrophobic forces and for complex (2) via hydrogen bonding and van der Waals interaction. The antioxidant activity of these complexes was investigated by DPPH (2,2-Diphenyl-1-picrylhydrazyl) assay. According to this test, the antioxidant activity compared to the standard sample (vitamin C) is as follows: vitamin C > 2 > 1. Furthermore, the docking result proposed the binding of these complexes to the groove of DNA.

In this research, we designed phthalocyanine compounds that are thought to be used as potential acetyl/butyrylcholinesterase inhibitors in the treatment of Alzheimer's disease. First, phthalonitrile compound (PNM-CN), which is the precursor compound for phthalocyanines, was synthesized. Then, by cyclotetramerizing this compound, pyridine-substituted peripheral cobalt (PNM-CoPc), copper (PNM-CuPc), and manganese (PNM-MnClPc) phthalocyanine compounds were synthesized, and their structures were described using mass, NMR (except phthalocyanines), FT-IR, and UV–Vis (except phthalonitrile) spectroscopic techniques. Investigations were carried out into the new pyridine-substituted peripheral (PNM-Cu/Co/MnClPcs) phthalocyanines' in vitro inhibitory properties against butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE). With an IC₅₀ of 5.95 ± 2.12 μM (AChE) and 0.74 ± 0.01 μM (BuChE), PNM-CuPc showed the most potent inhibitory effect against AChE and BuChE among all compounds.

Reconnoitre the use of earth-abundant metals for an essential organic reaction was extremely provocative from an industrial vantage point. In this study, the fundamental and energy-efficient co-precipitation approach was employed to aid the Cu₂O cubed nanostructured catalyst in the generation of benzimidazole and quinoxaline derivatives. The developed Cu₂O cubed nanostructured catalyst was thoroughly evaluated by world-class analytical and spectroscopic techniques. The Cu₂O cube catalyst exhibited exceptional crystallinity, a cubic shape, a large specific surface area and uniformly distributed active sites on its surface. The obtained astounding structural and physico-chemical characteristics successfully enabled the catalytic activity for the synthesis of benzimidazole and quinoxaline. The recognised vital structural and physical attributes substantially improved the catalytic activity for the production of benzimidazole and quinoxaline derivatives over mild reaction conditions. Employing a cubic Cu₂O catalyst, diverse reaction parameters have been examined, encompassing the effects of catalyst dosage, temperature, time, solvent, yield and substrate scope. As a result, the designed catalyst was used to synthesise heterocyclic 2-substituted benzimidazole and quinoxaline derivatives via the condensation of o-phenylenediamine, aldehydes and 1,2-diketone. The reported results showed 100% conversion in both aimed products, with 90% selectivity for 2-substituted benzimidazole and 95% selectivity for quinoxaline derivatives, respectively. The obtained yield for 2-substituted benzimidazole and quinoxaline derivatives was 85 and 98 at 60°C for 3 and 4 h, individually. The catalytic activity was fully based on the inherent properties of cubic Cu₂O. On top of that, all synthesised compounds were structurally validated by ¹H NMR, ¹³C NMR and mass spectrum data. Remarkably, the efficient cubic Cu₂O catalyst demonstrated impressive recyclability for up to six consecutive cycles with minimal loss of its initial catalytic activity. The spent cubic Cu₂O catalyst's characteristic results revealed evidence for its stable structural and physico-chemical features. In addition, we endeavoured to propose and describe a plausible reaction mechanism utilizing the developed nanostructured Cu₂O cubes for the synthesis of benzimidazole and quinoxaline derivatives.

A novel quinolinyl hydrazone ligand (NaphHQino) has been synthesized by condensation of 2-hydrazinyl-4,7-dimethylquinoline with 2-hydroxy-1-naphthaldehyde. Reactions of NaphHQino with copper(II), nickel(II), and cobalt(II)-chlorides yielded a series of novel complexes. Structures of the NaphHQino ligand, Cu-NaphHQino, Ni-NaphHQino, and Co-NaphHQino complexes have been inspected with the help of elemental and thermal analyses, magnetic susceptibility and molar conductivity measurements, infrared, electron spin resonance (ESR), proton nuclear magnetic resonance (¹H NMR), mass, and electronic spectra. The studied NaphHQino ligand acts either as a neutral NN-donor or as a dibasic tridentate NNO-donor, forming square-planar complexes. Molar conductivity measurements demonstrate a neutral character of the NaphHQino complexes. The ESR spectrum of the Cu-NaphHQino complex confirmed the proposed square-planar geometry with values of α² and β², demonstrating that the in-plane π-bonding character is less prominent than the covalent in-plane σ-bonding character. Implementing density functional theory at the B3LYP/6-311G(d,p) and LanL2dz levels, the molecular fundamental properties of NaphHQino and NaphHQino-complexes were assessed. NaphHQino ligand exhibited antineoplastic activity towards Ehrlich ascites carcinoma, and metal-NaphHQino complexes showed higher activity than NaphHQino. Molecular docking simulations were carried out, which supported the obtained results for antineoplastic activity.

The reactions of two equivalents of monoanionic bidentate [PN]-type ligand characterized by a dibenzophosphole-backbone with M (NR₂)₄ (M = Ti, R = Me; M = Zr, R = Et) afforded titanium and zirconium complexes. Two signals appeared in the solution, as evidenced by the presence of a minimum of two diastereomers in the corresponding ³¹P NMR spectrum. The X-ray crystallographic studies of the molecular structures of one of the two diastereomers complexes revealed distorted octahedral structures with phosphorus atoms coordinated to titanium and zirconium centers and the pyrrolido group coordinated to the metal center in the η¹-coordination, and the two dibenzophosphole rings exhibited π-π stacking interactions. Ethylene polymerization at 0.4 MPa using these complexes with dried modified methylaluminoxane (dMMAO) as a cocatalyst produced linear polyethylene (PE) with a melting point of 128°C–136°C. The polymerization activity for ethylene attained values of up to 276 kg/mol (Ti)·h and 223 kg/mol (Zr)·h at 50°C.

Phosphate and pyrophosphate can advance green chemistry as nontoxic and sustainable catalysts. This study presents the development of a novel series of solid composite catalysts, comprising AlCl₃ and alkaline-earth metal (pyro)phosphates. The efficacy of these catalysts in facilitating the hydrosilylation of olefins with hydrosilanes has been thoroughly examined. Adding aluminum chloride enhances the catalytic activity of calcium phosphate for the catalysis hydrosilylation reaction, enabling efficient conversion of various linear alkenes into corresponding adducts with excellent yields. Furthermore, this catalytic system exhibits remarkable stability, maintaining its activity over 15 cycles without significant decrease.

Under ultrasonication, the nanoscale supramolecular complex [Pb (QCA)₂]_n (NSC1) was formed by the self-assembly of lead nitrate and quinoline-2-carboxylic acid (QCA) as linking ligand. Pb^II exhibits a (O₂N₂) distorted square planner geometry, where the Pb^II atom coordinates to two QCA ligands, according to single crystal X-ray diffraction of 1. With a packing structure of 1, facing molecules are arranged in parallel planes and joined by multiple H-bonds and π-π stacking to form a three-dimensional network. NSC1 was examined using a variety of structural characterization techniques as well as spectrum studies. Despite the well-documented toxicity of lead, which is utilized in various products, the nanoscale supramolecular complex [Pb (QCA)2]n (NSC1) demonstrates considerable safety owing to its stability, remaining unaffected by degradation mediums, as corroborated by different techniques. So, under UV or ultrasonic wave conditions, it has been demonstrated that the heterogeneous catalyst NSC1 exhibits significant catalytic activity in presence of H₂O₂ against the breakdown of the indicated pollutants, indigo carmine (IC) and phenol (Ph), in very short times. Using the disodium salt of terephthalic acid, the photoluminescence probing method was applied to ascertain the reactive oxygen species and the reaction process mechanism.