A novel thiocarbamide functionalized graphene oxide supported bimetallic monodisperse Rh-Pt nanoparticles (RhPt/TC@GO NPs) for Knoevenagel condensation of aryl aldehydes together with malononitrile

Functionalization of the graphene provides various possibilities to improve the use of the graphene and to provide more chemical conversion to the graphene. In order to enhance its chemical and physical properties, the graphite which is mainly functionalized with heteroatom-based functional groups is followed intensively, but often results in the inoculation of heteroatoms as various functional groups. Here we show that the graphene oxide can be mainly functionalized with a single species of sulfur and can be reduced to form a graphene which is ftmctionalized with monothiol at the same time. By the help of thiocarbamide-functionalized graphene oxide (TC@GO) the monodisperse rhodium/platinum nanoparticles (RhPt/TC@GO NPs) have been synthesized as promising catalysts for the Knoevenagel condensation to benzylidenemalononitrile derivatives of aryl aldehydes. The monodisperse RhPt/TC@GO NPs have been prepared via a facile method. The novel thiocarbamide-functionalized graphene oxide (TC@GO) supported rhodium/platinum nanoparticles (RhPt/TC@GO NPs) are identified by characterization techniques such as the Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The spectroscopic and morphological studies of the monodisperse RhPt/TNM@GO NPs indicate the highly crystalline form, well dispersity, ultrafine structure and colloidally stable NPs. After fully characterization of prepared nanoparticles, the novel nanocatalysts have been tried for the Knoevenagel condensation to benzylidenemalononitrile derivatives of aryl aldehydes and show excellent catalytic activity and a yield over 99% by the reaction at room temperature within 8-35 min in the presence of malononitrile and derivatives of aldehyde. As a result, the prepared nanocomposites exhibit very good heterogeneous catalyst properties for Knoevenagel condensation reactions.