Synthesis Of Two-dimensional Crystalline Materials Based On Polydiacetylene

Since the discovery of graphene in 2004,two dimensional?2D?materials have attracted tremendous attention in the scientific community and industry.The two-dimensional materials have a variety of special excellent properties,such as ordered pore structure,good mechanical strength,huge specific surface area,special light/electrical properties,so it has a wide range of application in selective separation,green catalysis and electronic devices.And it maybe a very critical material in the future.At the beginning,we gave a brief introduction about the basic properties and the applications of several popular 2D materials,including graphene,transition metal dichalcognides?TMDs?represented by monolayered MoS₂,and black phosphorene.In addition to the above inorganic 2D materials,the synthesis of organic 2D materials is a very important issue in recent research.There are three main types of 2D materials,including covalent bonds 2D polymers,coordination 2D polymers prepared from the coordination of organic ligand and metal ion,and the special self-assembly 2D polymers?2D supramolecule?which can be obtained by using hydrogen bonds,static electricity and van der Waals force.The concept,synthesis methods and characterization of the organic 2D materials are explained in details in chapter one,as well as the current research progress of these three 2D polymers,and the research ideas of this paper are briefly described.Secondly,we synthesized two linear monomers with two terminal photoreactive groups?anthracene or maleimide?embedded in a diacetylene skeleton for covalent 2D polymer's synthesis.Both of them were crystallized and their single crystal structures were solved.They all show layered structures.Unfortunately,they are not suitable for the synthesis of 2D polymers.It was found that size of terminal group can be critical for diacetylene'arrangement.It is interesting to note that the maleimide groups in the monomer crystals are strongly stacking in antiparallel with a distance of about 3.5?.Based on this structure,we first demonstrated that the photo-induced[2+2]-cycloaddition topological reactions of the maleimide can be attempted in the crystal.This provides a new idea for the clean and efficient synthesis of cyclobutane type polyimide.Additionally,we synthesized a diacetylene monomer with two terminal maleic acid.The monomer may form a hydrogen bond cross-linked layered structure in the crystal.In a layer,diacetylenes can carry out the[1,4]addition topopolymerization.After polymerization of diacetylenes,this layered material involves in-plane covalent bonding and H-bonding can exfoliated into a free-standing 2D crystalline materials.In so far reported 2D materials,forces confining atoms in 2D plane are often strong interactions such as covalent bonding.We firstly demonstrate that hydrogen?H?-bonding can be utilized to assemble polydiacetylene towards a2D material which is stable enough to be free-standing.The H-bonding allows further splitting the material into ribbons,which can re-assemble,as the same as a zipper,leading to the first example of a healable 2D material.Moreover,this material may have potential applications in stretchable electronics and nano-wire cross-bar arrays.Finally,we synthesized a series of other similar structure of the polydiacetylene monomers,we found that the color of some monomer crystals can turn red after light irradiation,it is likely to have the polymerization of diacetylenes.Due to limited time,we did not carry out the further research.