MPI Campus Seminar: From Sea Lilies to Self-Alignment: Tools for NMR Structure Determination of Natural Products

Nuclear magnetic resonance (NMR) spectroscopy provides structure, dynamics and kinetics of molecules. In this work we apply it to determine the 3D structure of natural products which is one of the fundamental steps in characterizing new compounds. When these compounds cannot be crystallized, NMR spectroscopy is a powerful tool to obtain structural data in solution. While traditional NMR methods typically give local structural information, such as short-ranged distance or dihedral constraints, anisotropic NMR is able to provide orientational constraints with respect to a global molecular frame. For anisotropic NMR it is necessary to align the molecules, i.e. give them a preferential orientation with respect to the main magnetic field. While this is typically achieved by using anisotropic media such as liquid crystals, we show that the interaction of aromatic molecules with the main magnetic field is strong enough to induce alignment that is measurable and can provide the needed structural data.