Search Results (7)

In this paper, the clean high yielding, synthesis, and structure of the tetraphosphine ligand, 1,1′,2,2′-tetrakis-(di-isopropyl-phosphino)ferrocene, (tdipf), is described. In addition, improved synthesis methods for 1,1′,2,2′-tetrakis(diphenylphosphino)ferrocene, (tppf), and 2,2′-bis-(diphenylphosphino)-1,1′-dibromoferrocene are also reported, and the synthetic method is generalised to include the synthesis of 3,3′-bis-(diphenylphosphino)-1,1′,2,2′-tetrabromoferrocene. The related ligands 2,2′-bis-(iso-propylphosphino)-1,1′-bis-diphenylphosphinoferrocene (diprdppf) and 2,2′-bis-(di-isopropylphosphino)-dibromoferrocene have also been prepared and characterised. The crystal structure of the square planar bimetallic nickel (II) dichloride of tdipf is also described, together with a brief NMR study investigating the synthesis of this and related metal complexes. The crystal structures of the palladium and platinum dichloride complexes of 2,2′-bis-(di-isopropylphosphino)-1,1′-dibromoferrocene, bpdbf, are also discussed in the context of comparison with previously known crystal structures in the same general family. A general discussion on the synthetic methodology is given, along with indications for future research that other researchers might explore. Full article

Here, we show that direct femtosecond laser nanostructuring of monocrystalline Si wafers in aqueous solutions containing noble-metal precursors (such as palladium dichloride, potassium hexachloroplatinate, and silver nitrate) allows for the creation of nanogratings decorated with mono- (Pd, Pt, and Ag) and bimetallic (Pd-Pt) nanoparticles (NPs). Multi-pulse femtosecond-laser exposure was found to drive periodically modulated ablation of the Si surface, while simultaneous thermal-induced reduction of the metal-containing acids and salts causes local surface morphology decoration with functional noble metal NPs. The orientation of the formed Si nanogratings with their nano-trenches decorated with noble-metal NPs can be controlled by the polarization direction of the incident laser beam, which was justified, for both linearly polarized Gaussian and radially (azimuthally) polarized vector beams. The produced hybrid NP-decorated Si nanogratings with a radially varying nano-trench orientation demonstrated anisotropic antireflection performance, as well as photocatalytic activity, probed by SERS tracing of the paraaminothiophenol-to-dimercaptoazobenzene transformation. The developed single-step maskless procedure of liquid-phase Si surface nanostructuring that proceeds simultaneously with the localized reduction of noble-metal precursors allows for the formation of hybrid Si nanogratings with controllable amounts of mono- and bimetallic NPs, paving the way toward applications in heterogeneous catalysis, optical detection, light harvesting, and sensing. Full article

The C-3 functionalization of 1H-indazole could produce a lot of highly valuable pharmaceutical precursors, which could be used for the treatment of cancer and many other inflammatory diseases. This work was focused on the C-3 functionalization of 1H-indazole through Suzuki–Miyaura cross-coupling of 3-iodo-1H-indazole with organoboronic acids, catalyzed by various palladium catalysts immobilized over imidazolium ionic liquids, as well as catalyst recycling. A series of reaction parameters, including the substrate, catalyst, and ionic liquid, were fully investigated. It is significant to note that the yields of the present Suzuki–Miyaura cross-coupling were mainly determined by the catalyst and the solvent used, more than the chemical structure of the substrate. Furthermore, ferrocene-based divalent palladium complexes showed better catalytic outputs compared to simple palladium salts. Moreover, using two imidazolium ionic liquids, BMImX (BMIm⁺ = 1-n-butyl-3-methylimidazolium, X⁻ = BF₄⁻, PF₆⁻) not only improved the yields of cross-coupled products, but also avoided the formation of Pd⁽⁰⁾ black, as compared to the non-ionic liquid facilitated reactions, and simultaneously making catalyst recycling more effective. On average, BMImBF₄ performed better than BMImPF₆. Additionally, scientific calculations revealed that 1,1′-bis(diphenylphosphino)ferrocene-palladium(II)dichloride dichloromethane complex (PdCl₂(dppf)) showed a lower energy barrier in the formation of intermediates than [1,1′-bis(di-tert-butylphosphino)ferrocene]dichloropalladium(II) (PdCl₂(dtbpf)), leading to higher catalytic outputs. This work may contribute to the development of 1H-indazole-derived new pharmaceuticals. Full article

The luminal A-subtype of breast cancer, where the oestrogen receptor α (ERα) is overexpressed, is the most frequent one. The prodrug tamoxifen (1) is the clinically used agent, inhibiting the ERα activity via the formation of several active metabolites, such as 4-hydroxytamoxifen (2) or 4,4′-dihydroxytamoxifen (3). In this study, we present the tamoxifen derivative 4-[1,1-bis(4-methoxyphenyl)but-1-en-2-yl]-2,2′-bipyridine (4), which was combined with platinum or palladium dichloride, the former a well-known scaffold in anticancer treatment, to give [PtCl₂(4-κ²N,N′)] (5) or [PdCl₂(4-κ²N,N′] (6). To prevent fast exchange of weakly coordinating chlorido ligands in aqueous solution, a bulky, highly stable and hydrophobic nido-carborate(−2) ([C₂B₉H₁₁]²⁻) was incorporated. The resulting complexes [3-(4-κ²N,N′)-3,1,2-PtC₂B₉H₁₁] (7) and [3-(4-κ²N,N′)-3,1,2-PdC₂B₉H₁₁] (8) exhibit a dramatic change in electronic and biological properties compared to 5 and 6. Thus, 8 is highly selective for triple-negative MDA-MB-231 cells (IC₅₀ = 3.7 μM, MTT test), while 7 is completely inactive against this cell line. The observed cytotoxicity of compounds 4–6 and 8 against this triple-negative cell line suggests off-target mechanisms rather than only ERα inhibition, for which these compounds were originally designed. Spectroscopic properties and electronic structures of the metal complexes were investigated for possible explanations of the biological activities. Full article

One of the key factors for producing highly dispersed controlled nanoparticles is the method used for metal deposition. The decomposition of metal-organic precursors is a good method for deposition of metal nanoparticles with very small sizes and narrow size distributions on the surface of various supports. The preparation process of Pd and bimetallic Pd-Sn nanoparticles supported onto γ-Al₂O₃ is considered. The samples were prepared by diffusional co-impregnation of the γ-Al₂O₃ support by using organometallic Pd(acac)₂ and Sn(acac)₂Cl₂ precursors. To achieve the formation of Pd and bimetallic Pd-Sn nanoparticles on the support surface, the synthesized samples were then subjected to thermal decomposition under Ar (to decompose the organometallic bound to the surface while keeping the formed nanoparticles small) followed by an oxidation in O₂ (to eliminate the organic compounds remaining on the surface) and a reduction in H₂ (to reduce the nanoparticles oxidized during the previous step). A combination of methods (ICP-OES, TPR-H₂, XPS, TEM/EDX) was used to compare the physical-chemical properties of the synthesized Pd and bimetallic Pd-Sn nanoparticles supported on the γ-Al₂O₃. The three samples exhibit narrow size distribution with a majority on nanoparticles between 3 and 5 nm. Local EDX measurements clearly showed that the nanoparticles are bimetallic with the expected chemical composition and the measured global composition by ICP-OES. The surface composition and electronic properties of Pd and Sn on the γ-Al₂O₃ support were investigated by XPS, in particular the chemical state of palladium and tin after each step of thermal decomposition treatments (oxidation, reduction) by the XPS method has been carried out. The reducibility of the prepared bimetallic nanoparticles was measured by hydrogen temperature programmed reduction (TPR-H₂). The temperature programmed reduction TPR-H₂ experiments have confirmed the existence of strong surface interactions between Pd and Sn, as evidenced by hydrogen spillover of Pd to Sn (Pd-assisted reduction of oxygen precovered Sn). These results lead us to propose a mechanism for the formation of the bimetallic nanoparticles. Full article

Suzuki coupling reaction of 5-fluoro-6-methylpyridin-2-ylboronic acid (1) with 4-chloro-2-iodo-1-(trifluoromethyl)benzene (2) in the presence of dikis and K₂CO₃ produce C-C coupled new title compound 6-(5-chloro-2-(trifluoromethyl)phenyl)-3-fluoro-2-methylpyridine (3). The structure of the newly synthesized compound has been confirmed by IR, ¹H-NMR, ¹³C-NMR, LC-MS and CHN analysis. Full article