Small-Angle Neutron Scattering in Supramolecular Complexes

Abstract

A variety of analytic methods are utilized to elucidate the structure and dynamics of supramolecular nanoassemblies. Crystal engineering serves as an excellent tool to determine and manipulate the solid-state structures of large supramolecular nanoassemblies. Solution chemistry of supramolecular complexes, on the other hand, is more complex. Self-assembly reactions in solution are governed by noncovalent, reversible interactions which are difficult to map/discern. Traditional methods, such as NMR spectroscopy, have served instrumental in studying equilibrium conditions, diffusion of guest molecules, and self-sorting mechanisms of hydrogen-bonded and nonparamagnetic nanoassemblies in solution. However, a major limitation of NMR technique has been the investigation of paramagnetic species and the presumption about the spherical architectures of nanoassemblies in solution. The concept of intactness of solid-state geometries in solution is often questionable when we elucidate their solution properties. Small-angle neutron scattering (SANS) is a new tool that has proved beneficial in addressing some of the limitations of NMR spectroscopy. Not only does it provide architectural (shape and size) information, but also it is suitable for analyzing both diamagnetic and paramagnetic nanoassemblies in solution: superseding NMR limitations. This article focuses on discussing basics of SANS and data analyses, which include varying types of mathematical models utilized to elucidate supramolecular nanoassemblies in solution and soft matter (gel and polymers).