Self-assembling nanotubes based on guanine-cytosine module: Synthesis, assembly and structure studies

Nanoscale tubular architectures have attracted significant attention in recent years because of their promise for construction of electronic devices, sensor, storage and transport systems, and stimuli responsive materials. Rosette Nanotubes (RNTs) are biologically-inspired organic nanotubes that can be assembled from a small molecule that combines Guanine and Cytosine's hydrogen bond arrays. The ability to control dimensions with atomic precision, versatile outer surface functionalization procedures developed, tunable chirooptical properties and stability, along with biocompatibility make the RNTs a very attractive platform for construction of functional nanoscale materials. To assemble functional materials from the RNTs several current challenges have to be resolved. Possible solutions for three major challenges---understanding RNTs supramolecular structure, control of the aggregation and shape of their hierarchical assemblies, and making them conductive---are addressed in the respective chapters 2, 3, and 4 of this work.;In Chapter 1 the field of the self-assembled nanotubes is reviewed. The nanotubes are classified based on the type of the modules they are assembled from. Assembly of the nanotubes from hydrogen-bonded rosettes is reviewed in details. Challenges for the class of assembled organic nanotubes and for RNTs specifically are outlined and their possible solutions are discussed.;In Chapter 2 the structure of the GC module was established in solutionand in the solid state based on a number of 1 D and 2D NMR spectroscopy at different field strengths. It was found that only protonated WC modules, but not the rosettes, are observed by solution NMR. In the solid state, deprotonated GAC module was shown to have hydrogen bonding patterns consistent with rosette nanotube structure.;In Chapter 3 a number of hydrophobic Guanine-Cytosine derivatives were synthesized. The possibility of controlling the aggregation of the nanotubes into discrete hierarchical structure is demonstrated by SEM, TEM, AFM, DLS, XRD, and SAED on various surfaces and in solution.;In Chapter 4 helical RNT bundles were assembled and coated with silver. It was shown that the resulting Ag-RNT composites were conductive and SERS-active.