Journal of Organometallic Chemistry最新文献

The title compound was prepared through a three-step procedure starting with the hydride complex [Mo₂Cp₂(µ-H)(µ-P^tBu₂)(CO)₄], which was first dehydrogenated through reaction with HBF₄·OEt₂ to give the unsaturated complex [Mo₂Cp₂(µ-P^tBu₂)(CO)₄](BF₄) (Mo=Mo), which displays a transoid structure according to experimental (Mo-Mo = 2.8283(7) Å) and Density Functional Theory studies. The latter was then reacted with NO to give the dinitrosyl derivative [Mo₂Cp₂(µ-P^tBu₂)(CO)₂(NO)₂](BF₄), which in turn was further decarbonylated and nitrosylated upon reaction with [N(PPh₃)₂]NO₂ to give the title nitrosyl-bridged complex (Mo-Mo = 2.905(1) Å). This complex displayed a structure comparable to that of its PCy₂-bridged analogue, with similar pyramidalization of the bridging nitrosyl, but a more pronounced folding of the central MoPMoN skeleton and bending of terminal nitrosyls. It also displayed a similar NO bond activation chemistry, as shown by its reactions with HBF₄·OEt₂ to give the nitroxyl-bridged complex [Mo₂Cp₂(µ-P^tBu₂)(µ-k¹:η²-HNO)(NO)₂](BF₄) (HNO = 1.330(8) Å), with P(OEt)₃ to give the phosphoraniminate-bridged complex [Mo₂Cp₂(µ-P^tBu₂){µ-NP(OEt)₃}(NO)₂], and with Na(Hg) to give the amide-bridged derivative [Mo₂Cp₂(µ-P^tBu₂)(µ-NH₂)(NO)₂]. Under a nitrogen atmosphere, however, the latter reaction also gave a minor side product identified as the dinitrogen-bridged derivative [Mo₄Cp₄(µ-P^tBu₂)₂(µ₄-N₂)(NO)₄]. This tetranuclear complex displays a dinitrogen molecule bridging four metal atoms in the novel µ₄-k¹:k¹:k¹:k¹ coordination mode, with strong metal-nitrogen interactions taking the N₂ ligand to the diazendiide (N₂^2-) limit (NN = 1.241(3) Å).

Multicomponent reactions play a pivotal role in synthesizing 1H-pyrazole-4-carboxamides, underscoring its significance in sustainable organic synthesis. These compounds, valued for their diverse biological activities, have garnered substantial attention in pharmaceutical research. A facile, rapid one-pot strategy to access an extensive array of 1H-pyrazole-4-carboxamide derivatives, utilizing substituted aldehydes, cyanoacetamide, and hydrazine hydrate as substrates and a readily accessible Mn₂(CO)₁₀ as photocatalyst in EL: H₂O (1:1). Among the synthesized series, products 4b, 4 g, 4k showed remarkable antibacterial activity against E coli, P aeruginosa, S. aureus in agar medium and excellent cytotoxicity with Human colorectal carcinoma (HCT-116), Liver cancer cells (Hep-G2) and breast adenocarcinoma (MCF-7) cell lines. The current method is characterized by its affordability, non-toxicity, easy access to starting materials, and notably with minimal waste generation. Additionally, remarkable aspects include its mild operating conditions, environmentally friendly nature, and the ability to accommodate a wide range of both electron-donating and electron-withdrawing groups.

In this study, an organometallic nanocomposite consisting of polyaniline (PANI) and copper oxide (CuO) was synthesized using the in-situ polymerization method of aniline, with copper chloride serving as a polymerization catalyst and precursor, along with sodium hydroxide to synthesize CuO nanoparticles. Various techniques were employed to characterize the synthesized nanocomposite, including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-vis spectroscopy, scanning electron microscopy (SEM), and determination of pH of the point of zero charge (pH_pzc). The catalytic performance of the PANI/CuO nanocomposite was evaluated for the degradation of methylene blue (MB), both with and without ultrasonic irradiation. The nanocomposite catalyst exhibited significantly improved catalytic efficiency for MB degradation in ultrasonic irradiation, compared to degradation without ultrasonic irradiation. The experimental conditions were optimized using the Box-Behnken Design (BBD), resulting in finding that the highest MB degradation efficiency reached 95% under ultrasonic irradiation and 74% without it. These results were achieved with a dye concentration of 50 mg/L, a catalyst dose of 0.4 mg/L, and a contact time of 60 minutes. Theoretical calculations suggest that BM molecules promote an attacking mode owing to their electrophilic characteristics, which make them more likely to accept electrons. This propensity leads to the formation of an antibonding orbital in conjunction with PAN/CuO, indicating a synergistic effect between organic molecules (PANI) and inorganic nanoparticles (CuO). This synergistic effect enhances the catalytic activity. Furthermore, the catalyst has demonstrated excellent reusability and stability, suggesting its potential application as an efficient PANI/CuO nanocomposite catalyst for the removal of organic pollutants.

In this investigation, the VPO/Ce-OMS-2 composite was synthesized via the mechanochemical method and it was employed for the synthesis of imine in the liquid phase through a two-step process of oxidation of benzyl alcohol and subsequent condensation with aniline using air as an oxidant. The composite was synthesized with different mass ratios of (1:1), (1.5:1), (2:1) and (2.5:1). The effect of the VPO/Ce-OMS-2 mass ratio on catalyst activity has been investigated. As the mass ratio increases from (1:1) to (2:1), the benzyl alcohol conversion gradually increases, reaching 93% at a (2:1) mass ratio. Among the synthesized samples, the VPO/Ce-OMS-2(2:1) composite exhibited the highest selectivity towards imine formation and conversion of benzyl alcohol. Various techniques, such as XRD, FT-IR, BET, FESEM, EDX, DRS, NH₃-TPD, and HRTEM, were utilized to characterize the catalysts. Results indicated that the composite synthesized with a (2:1) mass ratio has a favorable surface area, a mixture of micro-meso structures, and a high number of acidic sites, as confirmed by BET-BJH and NH₃-TPD techniques. The DRS analysis demonstrated that the interaction between the two catalysts, VPO and Ce-OMS-2, enhances the selectivity for the desired product. The results clearly show the synergism effect in the combination of components VPO and Ce-OMS-2 and improving the activity and selectivity of the synthesized nanocomposite. The effects of reaction temperature, reaction time, solvents, VPO/Ce-OMS-2 mass ratio, catalyst amount, and reusability were studied. Recycling results for the VPO/Ce-OMS-2(2:1) composite show that the benzyl alcohol conversion decreases slightly after five cycles of use, and its stability is almost maintained. Optimizing the reaction conditions (0.2 g catalyst, VPO/Ce-OMS-2 mass ratio (2:1), solvent toluene, reaction temperature 90°C, and t = 8 h) resulted in a 93% conversion of benzyl alcohol with complete selectivity for the imine.

Siloxane star-shaped polymers have been obtained by sequential hydrothiolation and hydrosilylation of vinyl- and hydride-containing tetracyclosilsesquioxane. The mild conditions of these reactions avoid ring isomerization, opening the way to star-shaped polymers based on a stereoregular silsesquioxane ring. Monofunctional telechelic PDMS and a mixture of polymer star-shaped stereoisomers were synthesized as reference materials. All resulting compounds bore the same functional groups and were analyzed by GPC, TGA, DSC and NMR. The study of monolayers of these compounds on the Langmuir trough allowed to evaluate the influence of stereoregularity and pre-organization of the star PDMS on the parameters of the formed monolayers.

1,3-Diiminoisoindolines and substituted variants react with hydrazine to produce 1,4-diaminophthalazines. In this paper, we present the chemistry of 1,4-diaminophthalazine and two modified versions with the Re(CO)₃ unit. The 1,4-diaminophthalazine ligand forms a bimetallic complex similar to that seen with unmodified phthalazine. In contrast, the semihemiporphyrazine-derived chelating ligands bind Re(CO)₃ as neutral bidentate compounds; the freebase pyrazole and indazole modified 1,4-diaminophthalazines exhibit multiple tautomerization states with ionizable protons. Notably, protonation of the meso bridging nitrogen atom reduces the degree of conjugation between the two halves of the chelate, resulting in a diimine-like complex that lacks significant absorption in the visible spectrum due to the abrogation of the low energy metal to ligand charge transfer (MLCT) transition.