The Preparation And Properties Of Small Organic Molecule Modified Graphene Materials

The small organic molecule modified graphene materials were systematically investigated for Knoevenagel condensation reactions and C–N coupling reactions in this paper.These multifunctional graphene materials were synthesized through a simple preparation route,and detailedly analyzed by different characterization methods.The main studies were as follows:Firstly,the vitamin B1 fuctionalized graphene oxide material?GO–VB₁?was prepared though a one–pot route.And,copper were immobilized on the GO–VB₁ materials by the situ chemical reduction method?Cu–VB₁–G?.These materials were characterized by a variety of techniques,including Fourier transform infrared spectroscopy?FT–IR?,X–ray diffraction?XRD?,scanning electron microscopy?SEM?,X–ray photoelectron spectroscopy?XPS?,and transmission electron microscopy?TEM?and so on.These results showed that VB₁ had been successfully modified on graphene oxide sheets.Then,the copper nanoparticles had also been sucssfully immobilized on the graphene composite materials,and the valent of copper was mainly zero.The experimental results revealed the GO–VB₁ material as a heterogeneous catalyst for Knoevenagel condensation reactions exhibited good catalytic activity and excellent stability,and the catalyst was used at low dosage,as well as could be easily separated from the reation mixture.However,we have a research on the Cu–VB₁–G materials for C–N coupling reaction of iodobenzene and imidazole,only a middle yield can be obtained.The result may be due to the S element of VB₁ hindering the activity of the Cu–VB₁–G catalyst.Nextly,amino acids modified graphene oxide?A–GO?was also synthesized by a one–pot route.All the samples were analyzed by different characterization in details.These results showed that the A–GO as a heterogeneous catalyst could further catalyze Knoevenagel condensation reaction.This reaction system has some advantages,such as shorter reaction time,milder conditions,as well as green and harmless solvent.Additionally,the versatility and recyclability of the L–arginine–grafted graphene oxide?Arg–GO?were systematically investigated in Knoevenagel condensation reactions.Finally,1,3–diamino–graphene?NH₂–G–NH₂?materials were synthesized using a simple chemical method.The as–prepared materials were characterized in details.The results revealed that a 1,3–diamino group was successfully grafted on graphene and could immobilize CuI by coordination interactions.The NH₂–G–NH₂ materials can be used as heterogeneous ligands for Cu I–catalyzed C–N coupling reactions,and the desired products were obtained with good yields.The reaction system is much smoother at lower temperature compared with others previously reported.Additionally,the new method can easily realize the purification of products and recycling of catalysts.