Functionalized graphene oxide anchored to Ni complex as an effective recyclable heterogeneous catalyst for Sonogashira coupling reactions

The Sonogashira cross coupling reaction between alkynes and aryl halides is blooming as a general methodology for the construction of C(sp)-C(sp2) bonds [1]. Diarylethynes are versatile compounds in organic chemistry, and therefore, several procedure for their synthesis have been investigated [2]. Carbon-carbon triple bonds are very useful in the chemical industry such as new drugs and polymers, because they can be simply functionalized through multiple addition reactions. In chemical science, polyalkyne derivatives are applied to preparation carbon-rich materials, new carbon allotropes and organic LEDs [3,4]. The Sonogashira cross coupling reaction is an applied method used to prepare diarylethynes from readily available aryl halide derivatives and phenyl acetylene. The coupling reaction using N, N -Bis(2-hydroxyethyl)ethylenediamine on to core shell graphene oxide (GO@SiO2-BHED-Ni) as catalyst was studied in this research. The catalyst showed good thermal stability and recyclability in the reaction. Moreover the catalyst is simply separated and can be reused several times without significant loss of catalytic activity. A wide range of aryl halides was coupled successfully under palladium and phosphine free conditions. The use of this catalyst led to the formation of substituted aromatic alkynes in excellent yields and short reaction times.