Construction of two-dimensional polymers by an interfacial metal-organic complexation approach

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In 1922, Hermann Staudinger introduced the definition of polymers as macromolecules consisting of a high number of repeat units that are covalently linked to one another forming topologically linear structures. Today, the molecular architectures of these synthetic polymers and biopolymers meet the demands of modern technology covering almost every aspect of our modern life. Polymer chemistry has made great progress in understanding structural issues related to one-dimensional polymers (1DPs) regarding the control of molecular weight and weight distribution as well as stereochemistry and nature of end groups. However, these concepts cannot yet be applied for the synthesis of macromolecules with higher dimensionality like graphene (2DP) or diamond (3DP). Thus, very little success has been made so far in the development of synthetic approaches for the construction of 2DPs.The target of the proposed research is to open up passable and robust trails into monomolecular metal-coordination sheets by interfacial polymerization reactions with suitable monomer units obtained by rational organic synthesis. The monomers will be based on shape-persistent units carrying for lateral bipyridine (bpy) ligands so as to connect them to one another by square planar metal complexation. While with weakly binding metal ions these sheets cannot be considered covalent, with more strongly binding metal ions such Ni2+ and Pt2+ they may reach mechanical stabilities comparable to fully covalently bonded sheets. In addition, it is of great interest to gain a basic insight into the internal order and mechanical properties of these two-dimensional polymers, which shall be investigated by a number of techniques including AFM, STM, SEM, TEM, GISAXS, Raman, etc. to pave the way for future applications of these innovative materials.