NMR diffusion and relaxation correlation methods: New insights in heterogeneous materials

Heterogeneous materials, such as biological tissues, foodstuffs, and rocks, contain a range of microscopic environments where the molecular constituents often have different NMR relaxation time constants and self-diffusion coefficients. Multidimensional correlation methods have greatly improved the possibility for separating and assigning the NMR responses from distinct environments, thereby allowing for a more complete characterization of structure, dynamics, and molecular exchange in heterogeneous materials. Here, we review recent developments in experimental methodology and data analysis approaches.