Applied Organometallic Chemistry最新文献

Seven Ni(II) complexes (1–7) designed from a new nitrogen-rich ligand 1,3-bis(phenyl(pyridin-2-yl)methylideneamino)guanidine hydrochloride (H₃L‧ HCl) are reported. The complexes were synthesized using in situ one-pot method and characterized by elemental analyses, FT-IR, Far-IR, electronic solution-phase spectra, solid-state electronic diffuse reflectance spectra (UV-DRS), conductivity measurements, and room temperature magnetic moment calculations. The structures of H₃L‧ HCl and complex 7 were confirmed via SCXRD analysis. Additionally, complex 4 on crystallization yielded a new mononuclear complex, [Ni(H₂L)]Cl‧ 2H₂O (4a), which was confirmed by SCXRD analysis. The molecular packing of the compounds is affected by the counter anions and stabilized by various noncovalent interactions within the crystal lattice, which were analyzed quantitatively by Hirshfeld surface analysis. The band gaps of the compounds indicate semiconductor characteristics, which were evaluated experimentally and subsequently analyzed by DFT calculations. The catalytic investigation reveals that the Ni(II) complex 7 facilitates a cinnamyl alcohol conversion of 90% with a selectivity of 92% for cinnamaldehyde under the optimal reaction conditions of 80°C for 24 h, employing TBHP in decane as the oxidizing agent. Similarly, all other complexes are also found to exhibit comparable conversions in the range of 81%–91% under optimal conditions. Furthermore, in silico molecular docking studies demonstrated the binding affinity of the ligand and complex 4 with SARS-CoV-2 main protease active site (M^pro), which makes them suitable candidates for further biological exploration.

Fischer–Tropsch synthesis (FTS) is an essential strategy for mitigating the energy crisis, combating climate change, and promoting sustainable development. Supported cobalt-based catalysts exhibit significant activity in FTS, but their product selectivity requires further optimization. In this paper, Co@SiO₂ catalysts with core-shell structure were prepared by hydrothermal synthesis. The effect of the SiO₂ shell thickness on the catalytic performance of FTS was explored by varying the amount of ethyl orthosilicate (TEOS) added with stabilizer polyvinylpyrrolidone (PVP). Among them, the catalyst CS3 achieved the greatest number of cobalt active sites, the highest CO conversion (77.2%), and C₅₊ selectivity (84.3%) with a high C₅-C₁₁ proportion in the C₅₊ product. Characterizations of the catalysts were performed to examine their morphology and physicochemical properties. It was observed that the dispersion of cobalt species improved with increasing shell thickness within a certain range, promoting the reduction of cobalt species. However, the formation of Si-OH groups because of the hydrolysis of excess TEOS clogged catalyst pores, consequently diminishing the catalytic activity in FTS. Compared with the CS3-PVP0 catalyst without stabilizer PVP added, the catalyst CS3 with PVP added exhibited obvious ordered morphology, making CO conversion significantly enhanced. This is attributed to the role of inert carbon in PVP, which not only boosts the reducibility of cobalt species but also enhances the surface hydrophobicity of the mesoporous SiO₂ material.

Recently, a series of inexpensive nickel-based phosphine phenol catalysts have been synthesized for catalyzing the copolymerization of ethylene and polar monomers to prepare functionalized polyolefins. However, it is still challenging to achieve homogeneous nickel catalysts that catalyze ethylene polymerization or copolymerization at high temperatures (up to 150°C) with high activity. This work synthesized a series of phosphine phenol nickel catalysts with bulky steric hindrance and electron donating groups, which were used for catalyzing ethylene polymerization and coordination copolymerization of ethylene and a series of polar monomers at high temperatures. These nickel catalysts exhibited high ethylene polymerization activity and excellent thermal stability at 150°C, producing polyethylene with a molecular weight of up to 102.7 × 10⁴ g mol⁻¹. More importantly, these catalysts can catalyze the copolymerization of ethylene and a range of polar monomers at 120°C, improving the surface properties of polyolefins.

There are still challenges to eliminate and reduce the harmful persistent organic pollutants (POPs) in the water, especially the dye-based POPs. Two big obstacles the Ag₃PO₄ photocatalyst faces are serious carrier recombination and photocorrosion, which presents a limitation for its application in water purification. Therefore, in this work, a novel Ag₃PO₄/SrTiO₃ heterojunction was synthesized by a simple in situ deposition method. Ag₃PO₄/SrTiO₃ 10:1 exhibits the highest photocatalytic activity with rhodamine B (RhB) degradation of 98.8% in only 20 min and methyl orange (MO) degradation of 97.5% in 80 min under simulated sunlight irradiation, which is much higher than that of pure Ag₃PO₄ and the mixed photocatalysts. During the photocatalytic reaction, h⁺ and •O₂⁻ are the main active species, and the charge transfer path is satisfied with the Z-scheme mechanism. Additionally, the possible degradation pathways of RhB and MO were proposed by analyzing the intermediate products via HPLC-MS.

Quinolines obtained from native trees of South and Central America, of the genus Cinchona, have been used since the 17th century for the treatment of malaria. However, it was only in 1820 that quinine had its structure elucidated, and subsequently, during the 20th century, several synthetic derivatives were produced with quinine superior activities. In parallel, the search for the synthesis of metal complex compounds for the treatment of malaria dates from 1994, with the development of ferroquine, an iron complex derived from chloroquine, developed by Biot and collaborators at Lille University. After, there are several metal complexes synthesized from quinine with various metals, such as ruthenium, gold, iridium, and platinum, over the last 30 years, which are the aims of this review. This review identified 84 quinoline–metal complexes reported across 25 studies, with the gold complex (Complex 63) showing significant potency against the FcBI strain (IC₅₀ 10 nM), outperforming chloroquine (CQ, 50 nM), indicating that metal coordination enhances the drug's action. The ruthenium complex (Complex 03) exhibited activity against PFB but was less effective than CQ (IC₅₀ 22.5 vs. 8.2 nM). Other complexes, such as Au(III) (Complex 61), Ir(I) (Complex 52), and Ir(II) (Complex 50), also demonstrated promising results with varying effectiveness across different strains. Structural features, including linear geometry in Au(I) complexes and square planar or piano stool geometries in Ru(II) and Ir complexes, play crucial roles in influencing their biological activity. These findings highlight the potential of metal coordination in improving antimalarial efficacy.

The complexes of Pd (II), VO (II), Cu (II), and Ni (II) with Schiff base (ABDS) derived from 2-aminobenzothiazole with 4-(diethylamino)salicylaldehyde have been prepared. Various spectroscopic methodologies for analysis, which might include ¹H, ¹³C NMR, infrared spectra (IR), ultraviolet–visible (UV–vis), and magnetic values, have been applied to elucidate the construction of these chemicals. For each complex, the most suitable form has been proposed as a result. The chemical compound behaves as a bi-dentate via NO donors into the material ions within octahedral shape about Cu²⁺, octahedral geometry for Ni²⁺, square pyramidal for VO (II), and square planner form around the Pd²⁺ ion. The substances were tested against different bacterial and fungal strains. They demonstrated effective inhibition against the harmful bacteria under study and cytotoxic activity (IC₅₀) against (HCT-116 cell line), (HepG-2), and (MCF-7). The metal chelates were shown to possess more antimicrobial activity than the free Schiff base chelate. The ABDS ligand had only moderate antioxidant activity, but the combined forms of V (IV), Ni (II), Cu (II), and Pd (II) exhibit more antioxidant activity than the ligand. These findings also corroborated the hypothesis that the combinations produced have antioxidant effects against DPPH free radicals comparable with those of regular vitamin C.

A simple and efficient approach was developed for ligand-free copper-promoted N-arylation of pyrazolo[1,5-a]pyrimidin-7-amines with aryliodides. A series of diarylamines and triarylamines could be obtained by controlling the reaction conditions. The reaction exhibited good functional-group tolerance, the feasibility of scale-up, and selectivity that make it particularly well suited for potential applications both in academic and industrial perspectives.

A series of heterometallic trinuclear aryloxides, [REZn₂(sal-Me)₄Cl₃(H₂O)] (Hsal-Me = methyl salicylate; RE^III = Y^III (3), Ho^III (4), Er^III (5)), or hexanuclear aryloxides, [RE₂Zn₄(μ₃-OH)₂(μ-OMe)₂(sal-Me)₆Cl₄] (RE^III = Y^III (6), Ho^III (7), Er^III (8)) were synthesized via the reaction of zinc precursors [Zn₄(sal-Me)₈] (1) or [Zn₄(μ₃-OMe)₂(sal-Me)₆] (2) with 2 equiv of rare earth chlorides (RECl₃). The catalytic activity of complexes 1–8 was evaluated in the ring-opening polymerization (ROP) of pentadecanolide (PDL) and hexadecanolide (HDL) to assess the effect of the initiator structure on the polymerization process and the physicochemical properties of the resulting polyesters. The obtained low molecular weight polypentadecanolides (PPDLs) and polyhexadecanolides (PHDLs) were investigated as modifying agents for commercial polylactide (PLLA) resin and used to prepare PLLA/PPDL or PLLA/PHDL blends.

Blending PLLA with PPDL or PHDL broadens its cold crystallization exotherm, shifts the T_cc to higher temperatures, and hinders the growth of PLLA crystals, ultimately leading to reduced thermostability and faster degradation.

An unprecedented C-SO oxidative-cleavage reaction was disclosed for fused thiazoline-1-oxide-azolium salts with Ag₂O to afford C_carbene^SO₂ palladacyclic complexes. The complex could undergo reversible redox reactions with Br₂ to afford an intermediary N-heterocyclic carbene (NHC) complex with a sulfonyl bromide dangling group. This complex allowed divergent hydrolysis, alcoholysis, and aminolysis to prepare a series of sulfonate and sulfonamide functionalized NHC complexes and a C_carbene^NSO₂ palladacycle via further deprotonation. Selected complexes were employed in catalysis to show excellent activities in the aqueous Suzuki-Miyaura coupling reactions and hydroamination reactions of aryl alkynes.

MOF-199 is modified by copper nanoclusters in three different solvents (H₂O, DMF and H₂O + DMF) to improve its performance in simultaneous removal of methyl mercaptan and hydrogen sulfide from natural gas. The composites are characterized by sorts of evaluation methods, and their capacities for removal of methyl mercaptan and hydrogen sulfide from natural gas are evaluated. The results show that copper nanoclusters are successfully loaded on MOF-199, and the morphology and crystal structure of the modified MOF-199 do not change significantly compared with pure MOF-199. However, the type of solvent and the content of copper nanoclusters affect the specific surface area and pore size of MOF-199. The highest specific surface area of 1177 m² g⁻¹ is reached when 0.24-wt% copper nanoclusters are loaded on MOF-199 in H₂O. This sample presents a total pore volume of 0.58 cm³ g⁻¹, an average pore size of 2.01 nm, and the highest breakthrough capacities for H₂S (41.25 mg g⁻¹) and CH₃SH (71.42 mg g⁻¹), which are 33.75% and 65.59% higher than that of pure MOF-199, respectively. This demonstrates that the modification of MOF-199 by copper nanoclusters can further boost the removal efficiency of H₂S and CH₃SH.