In-plane pyridinium cation reorientation in bis-thiourea chloride, bromide and iodide: quasielastic neutron scattering combined with molecular dynamics simulations

Unravelling Guest Dynamics in Crystalline Molecular Organics Using 2H Solid-State NMR and Molecular Dynamics Simulation

2H solid-state NMR and atomistic molecular dynamics (MD) simulations are used to understand the disorder of guest solvent molecules in two cocrystal solvates of the pharmaceutical furosemide. Traditional approaches to interpreting the NMR data fail to provide a coherent model of molecular behavior and indeed give misleading kinetic data. In contrast, the direct prediction of the NMR properties from MD simulation trajectories allows the NMR data to be correctly interpreted in terms of combined jump-type and libration-type motions. Time-independent component analysis of the MD trajectories provides additional insights, particularly for motions that are invisible to NMR. This allows a coherent picture of the dynamics of molecules restricted in molecular-sized cavities to be determined.

Orientational ordering of guest induced structural phase transition coupled with switchable dielectric properties in a host–guest crystal: bis(thiourea) thiazolium chloride

A host–guest crystal: (thiazolium)[(thiourea)₂Cl] undergoes order-disorder structural phase transition at 213.7 K, accompanied by distinct switchable dielectric responses.