Palladium(II) octaalkoxy- and octaphenoxyphthalocyanines: Synthesis and evaluation as catalysts in the Sonogashira reaction

Preparation of magnetic biochar functionalized by polyvinyl imidazole and palladium nanoparticles for the catalysis of nitroarenes hydrogenation and Sonogashira reaction

Catalysts are essential materials in biotechnology, medicine, industry, and chemistry. On the other hand, recycling and using waste materials is important in economic efficiency and green chemistry. Thus, biochar was prepared from the stem and roots of the Spear Thistle to recover waste. After magnetizing the biochar, its surface was modified with polyvinyl imidazole. Finally, this modified biochar was decorated with Pd nanoparticles and used as a selective and recyclable nanocatalyst in the hydrogenation of nitroarenes and the Sonogashira reaction. The structure of this organic-inorganic nanocatalyst has been characterized by FESEM-EDS, XRD, FT-IR, TEM, and VSM techniques. In the hydrogenation reaction with the amount of 30 mg of nanocatalyst, the temperature of 50 °C in the water solvent, the reaction efficiency reached 99% for 30 min. In addition, under optimal conditions for the Sonogashira reaction: 1.0 mmol iodobenzene, 1.2 mmol phenylacetylene, 20 mg MBC-PVIm/Pd, 2 mmol K2CO3 in H2O at 50 C for 15 min, the reaction efficiency reached 95%. The recyclability of magnetic nanocatalysts was investigated and recognized this nanocatalyst can be used several times without notable loss of its activity.

Design, synthesis and biological evaluation of novel indole-3-carboxylic acid derivatives with antihypertensive activity

Molecular design, synthesis, in vitro and in vivo studies of novel derivatives of indole-3-carboxylic acid - new series of angiotensin II receptor 1 antagonists is presented. Radioligand binding studies using [¹²⁵I]-angiotensin II displayed that new derivatives of indole-3-carboxylic acid have a high nanomolar affinity for the angiotensin II receptor (AT₁ subtype) on a par with the known pharmaceuticals such as losartan. Biological studies of synthesized compounds in spontaneously hypertensive rats have demonstrated that compounds can lower blood pressure when administered orally. Maximum the decrease in blood pressure was 48 mm Hg with oral administration of 10 mg/kg and antihypertensive effect was observed for 24 hours, which is superior to losartan.

Ambipolar Nickel Dithiolene Complex Semiconductors: From One- to Two-Dimensional Electronic Structures Based upon Alkoxy Chain Lengths

Air-stable single-component ambipolar organic semiconductors that conduct both holes and electrons are highly desired but have been rarely realized. Neutral nickel bis(dithiolene) complexes are promising candidates that fulfill the stringent electronic requirements of shallow HOMO levels and deep LUMO levels, which can reduce the carrier injection barrier to overcome the work function of gold electrodes and ensure air stability. However, most nickel bis(dithiolene) analogs that have been characterized as ambipolar semiconductors have twisted molecular structures that hinder the effective intermolecular interactions required for carrier conduction. To address this issue, we synthesized planar alkoxy-substituted nickel bis(dithiolene) analogs that facilitate dense packing with effective intermolecular interactions. Remarkably, changing the methoxy substituents to ethoxy or propoxy groups led to a dramatic change in the packing mode, from one-dimensional to herringbone-like, while maintaining effective intermolecular interactions. These materials overcome the usual trade-off between crystallinity and solubility; they are highly crystalline, even in their film forms, and are highly soluble in organic solvents. They are therefore readily solution-processable to form semiconducting layers with well-defined and well-ordered structures in field-effect transistors. Devices based on these compounds exhibited efficient ambipolar characteristics, even after several months of exposure to air, achieving high carrier mobilities of up to 10^-2 cm² V^-1 s^-1 and large on/off ratios of up to 10⁵, which are the top-class performances achieved for a single-component ambipolar semiconductor material driven in air.

Copper and palladium bimetallic sub-nanoparticles were stabilized on modified polyaniline materials as an efficient catalyst to promote C-C coupling reactions in aqueous solution

Modified polyaniline self-stabilizing Cu/Pd bimetallic sub-nanocluster composite materials (Cu/Pd@Mod-PANI-3OH) are obtained through the three steps of oxidative polymerization, structural modification, and metal self-trapping. Palladium and copper are confined and coordinated in the composite material by participating in the reaction and are highly uniformly dispersed in the carrier in the form of sub-nano clusters. The Cu/Pd@Mod-PANI-3OH micro-nano reactor catalyst formed by the self-assembly of copper, palladium and polyaniline has excellent electronic effects, including a tunable microenvironment, metal-carrier and metal-metal synergy, and the stabilizing effect of metal by polyaniline materials. It can efficiently catalyse C-C coupling (Sonogashira and Suzuki) reactions in aqueous solution with high catalytic activity and a wide range of applications (40 substrates). The characterization test results show that the Cu/Pd@Mod-PANI-3OH composite material obtained by self-trapping metal is a kind of prefabricated catalyst. During the reaction process, the high-valent metals in the pre-catalyst are in situ converted into active zero-valent metals. The catalyst's pre-fabrication strategy well protects the catalytic active centre, largely prevents agglomeration of the metal particles (can be recycled 8 times) and exhibits excellent interfacial domain-limited catalysis. The research strategy of modulation of catalytic active sites to improve the properties of materials at the molecular and atomic level reported in this article will open a new door in the research of polyaniline materials.

Simple synthesis of poly (1,4-bis(dodecyloxy)-2,5-diethynylbenzene)/Pd composites with catalytic activity in Sonogashira coupling reaction

Palladium on the polymeric materials (Pd@polymer) as a catalyst is now very promising due to its great prospect for catalytic application. Such material in the form of composites is found to be stable and can be applied as catalyst in organic synthesis like Sonogashira coupling reaction. In the present work, Pd containing conjugated poly-ynes composites (Poly (1,4-bis(dodecyloxy)-2,5-diethynylbenzene) (Poly-DEB)/Pd) were synthesized by varying the addition of Pd in the range of equivalent weight of 8:4, 8:2 and 8:1, maintaining the fixed amount of 1,4-bis(dodecyloxy)-2,5-diethynylbenzene (DEB) through chemical oxidative polymerization technique. Both FTIR and UV-visible spectroscopy confirmed the interactions between DEB and Pd in the composites. The DSC data revealed the improved melting temperature as well as the crystallinity of the composites than the DEB. The PL spectra showed its florescence property. The catalytic capability of the Poly-DEB/Pd composites were examined using the Sonogashira coupling reactions, which demonstrated good yields. The suggested synthetic protocol is very facile, reproducible and beneficial for the fabrication of diverse mono and bimetallic composites with conjugated polymers. The present study also demonstrates the new example of Poly-DEB/Pd composites catalyzed Sonogashira coupling reaction. These composites have a possibility to develop as a commercial reagent in various organic synthesis subjects to its application prospects.

Green synthesis of graphene oxide (GO)-anchored Pd/Cu bimetallic nanoparticles using Ocimum sanctum as bio-reductant: an efficient heterogeneous catalyst for the Sonogashira cross-coupling reaction

Here we report the synthesis and characterization of graphene oxide anchored Pd–Cu bimetallic nanoparticles by bio reduction method and its application in Sonogashira cross-coupling reaction.