Molecular association in deuterated liquid N-methylacetamide–water complex: Neutron diffraction and density functional theory study

A structural investigation of fully deuterated liquid N-methylacetmide–water complexes (NMA-W) is performed at 308 K and atmospheric pressure by using neutron diffraction in combination with a density functional theory (DFT). The data are analyzed to yield the molecular form factor F1(Q) and the distinct pair correlation function gL(r). DFT calculations are performed to examine some possible clusters that may describe the local arrangement in the liquid state. Neutron measurements can be interpreted in term of trans-NMA-3D2O complex. In this model there are two water molecules hydrogen bonded to the CO oxygen and one to the N–H group. The intermolecular structure factor extracted from this cluster fairly agrees with the experimental one beyond Q = 3 Å−1.