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A graphene based composite with copper nanoparticles (Cu-G) has been synthesized and used as catalyst for N-arylation and O-arylation. The structure and composition of the nanocomposite have been characterized by TEM, AFM, Raman and XPS. The catalytic activity of the Cu-G has been tested for the N-arylation of N-H heterocycles using arylboronic acids and the O-arylation of phenols using aryl halides.The catalytic N-arylation produces N-aryl heterocyles and the catalytic O-arylation produces diaryl ethers, under mild reaction conditions with excellent yields and selectivities. The developed catalyst is air-stable, inexpensive, easy to prepare, easy to recover by simple filtration and can be reused without appreciable loss of activity.

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Abstract. This research investigates changes in the nanostructure and the nanoscale local mechanical properties of cement paste with micro-and nano-modifiers. Silica fume and multiwall carbon nanotubes (MWCNTs) were used as micro-and nano-modifiers. An effective method of dispersing CNTs in cement matrix was developed. A detailed study on the effects of CNTs concentration and aspect ratio on the fracture properties, nanoscale properties and microstructure of nanocomposite materials, was conducted. Significant improvements on the macro and nanomechanical properties of cement paste were observed with the incorporation of CNTs. Results suggest that CNTs can strongly modify and reinforce the cement paste matrix at the nanoscale.