Synthesis of microporous hydrogen-bonded supramolecular organic frameworks through guanosine self-assembly

Abstract

Summary: Extending the structural hierarchy and complexity through small-molecular self-assembly is a powerful way to obtain large discrete, functional molecular architecture. A hydrogen-bonded supramolecular organic framework (HSOF) with nanometer-size pores is constructed in a solid state with simple guanosine-monomer self-assembly. To extend the hierarchy of the G-quartet self-assembly to a higher order than that of the traditional G-quadruplex, H-bond acceptors on the C-8 position of guanosine are introduced to establish inter-quadruplex linkage via H bonding to N(2)-HB from the neighboring G-quartet. After screening different C-8 substitution groups and various synthesis conditions, HSOF-G1a’ is obtained by solvent evaporation under diluted condition. Single-crystal X-ray structure reveals that cubic repeating units formed by G8 are the supermolecule secondary building block (SBU) with large pores (d = 34 Å). To our knowledge, this is the first G-quartet self-assembly with an organized structure beyond cylindrical G-quadruplexes.

Keywords

• guanosine
• G-octamer
• inter-quartet interaction
• hydrogen-bonded supramolecular framework
• hierarchical self-assembly
• fluorescence