Design,Synthesis And Characterization Of ?-conjugated System Grafted Graphene Via Suzuki Coupling Reaction

The primary coverage of this study is the bromination of graphene,and the suzuki coupling reaction between brominated graphene and aryl boric acid ester catalyzed by tetrakis(triphenylphosphine)palladium(0).?-conjugated system grafted graphene materials was obtained through this method.The bromination of graphene extend the modification application of graphene,and the combination by C-C bond exhibit the excellent properties of graphene.The main contents of this paper are list in the following:(1)The recent progress and prospect applications of graphene oxide/graphene materials is reviewed.The synthesis procedure,property,chemical modification,composites and application of graphene oxide/graphene materials was introduced and discussed.Otherwise,the mechanism,laden palladium catalysts and the applications of cross coupling reaction was illustrated.(2)To obtain graphene dispersity without any surfactant,modified Hummers method was used to prepare graphite oxide,followed by the reduction of hydrazine hydrate under the condition of hot bath.With the assistance of ultrasonic,brominated graphene was obtained when the dimensional nanosheets of graphene react with liquid bromine.The result of X-ray photoelectron spectrom indicates the formation of C-Br bond.This could open new synthetic possibilities for designing novel functionalized graphene,further expanding the versatility and applications fields of this fascinating allotropic family of carbon.(3)Two different aryl boric acid ester was obtained when brominated aryl compound react with trimethyl borate,which catalyzed by n-butyllithium under-78 ??One is 4-hexylphenyl boronic acid,which can only react with brominated graphene as a single molecule.The other is 7-bromo-9,9-dihexyl-fluorene-2-ylboronic acid,which can react with each other and graft to the surface of graphene as a macromolecule.The result of 1H-nuclear magnetic resonance revealed the succeed synthesis of two different kinds of aryl boric acid ester.(4)Single molecule and macromolecule graft graphene material was obtained with the formation of C-C bond,which catalyzed by tetrakis(triphenylphosphine)palladium(0).Various techniques such as infrared spectrometry,thermogravimetric analysis and X-ray powder diffraction was conducted to characterize these two new composites.In additional,the dispersity test,ultraviolet spectrometry indicates the composites has a good dispersity and a obvious change of their optical property.Similar to microwave-assisted bromination of carbon nanotubes,brominated graphene-based materials can represent a useful class of intermediates as they could act as precursors to a number of organometallic species,and suitable substrates for metal-catalyzed cross coupling reactions as the suzuki coupling reaction studied in this paper.What's more,the C-Br bond can be easy convert to-OH,-NH2,alkyl-NH2 and other functional groups by hydrolysis,ammonia treatment,and grafting of functional molecules,thereby enabling the exploitation of graphene materials in a wide range of applications.