Residual dipolar coupling

Residual dipolar coupling (RDC) is a phenomenon observed in nuclear magnetic resonance (NMR) spectroscopy, particularly in the study of macromolecules like proteins and nucleic acids. It arises when the molecular motions of a system are restricted, leading to a partial alignment of the molecule in a magnetic field. This partial alignment can be due to various factors, such as the presence of an anisotropic medium, interactions with alignment agents, or specific molecular interactions.