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A Au nanoparticle-reduced graphene oxide nanocomposite (Au NPs-RGO) was used as an effective and reusable heterogeneous catalyst for the Ullmann homocoupling of aryl iodides with short reaction times and good yields. For the first time, aryl bromides bearing electron-withdrawing groups were coupled in the presence of a catalyst giving moderate yields.Supported Au nanoparticles (Au NPs) and their catalytic applications in heterogeneous organic reactions have attracted considerable attention in recent years. Aldehyde-alkyne-amine coupling (A3-coupling), 1 oxidation of alcohols, 2 secondary amines 3 and carbon monoxide, 4 hydrogenation of olens, 5 Suzuki 6 and Sonogashira 7 reactions, formation of nitrogen containing compounds, 8 etc. are some of the most important applications of supported Au NP catalysts. The catalytic performance of Au NPs-support strongly depends on the size and shape of the Au NPs, the nature of the support, and the Au NPs-support interface interaction. 9 Supporting carriers may function by dispersing and xing the Au NPs. Supports such as oxides (CeO 2 , 10 SiO 2 , 11 Al 2 O 3 , 12 MgO 13 and TiO 2 (ref. 14)), mixed oxides (Mg-Al-O 15 and Ga-Al-O 16 ), polymers (PVP 17 and PS derivatives 18 ) and ordered mesoporous carbon 19 have been used as supports for Au NPs. Among these, it has been reported that the p-interaction of aromatic rings with gold nanoparticles leads to nanoparticle stabilization and improves the catalyst performance in a variety of gold-catalyzed reactions. 9,18,20 Graphene is a two-dimensional sheet of sp 2 bonded carbon atoms, which can be viewed as an extra-large polycyclic aromatic molecule. 21 Recently, graphene has been used as the support for metal and metal oxide that is mainly due to its large surface area, excellent electrical and thermal conductivity, low price, high chemical inertness, ease of modication and strong

An N-heterocyclic carbene Pd complex immobilized on GO with an ionic liquid framework synthesized by the modification of GO through a silylation reaction displayed a high catalytic activity in the Suzuki reaction.

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A new fiber based on the electrochemical reduction of graphene oxide was prepared on a copper wire for solid-phase microextraction (SPME) applications. The prepared fiber was used for the SPME and gas chromatographic analysis of tricyclic antidepressants (TCADs), including amitriptyline, trimipramine, and clomipramine. The feasibility of direct-immersion and headspace modes of SPME for the determination of TCADs was studied. The effects of four parameters including pH, salt content, extraction temperature with and without cooling the fiber, and extraction time were investigated. The comparison showed that headspace cold fiber SPME results in the best outcome for the extraction of TCADs. Under the optimized conditions of this mode, the calibration curves were linear between 2.0 and 500 ng/mL and the detection limits were between 0.30 and 0.53 ng/mL. The intraday and interday RSDs obtained at 20 ng/mL (n = 5), using a single fiber, were 5.5-9.0 and 7.5-9.8, respectively. The fiber to fiber repeatability (n = 4), expressed as the RSD, was between 12.8 and 13.2% at a 20 ng/mL concentration level. The method was successfully applied to the analysis of TCADs in plasma samples showing recoveries from 73 to 96%.

The water-dispersible and magnetic separable Au/Fe3O4/s-G nanocomposite was used as an effective and reusable heterogeneous catalyst for the Ullmann homocoupling.

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