Crystal and molecular structure of N-methyl-N-3(sulfonato)propyl-3-[tris(trimethylsiloxanyl)3-silyl]pyrrolinium sulfobetaine hydrate at room temperature and 163 K

2 (C17H41NO6SSi4) H2O. M-r = 1017.88, triclinic, space group P 1. The molec ules are arranged in bilayers. The molecules in each bilayer are held toget her by electrostatic forces, i.e., O-N+ contacts, and hydrogen bonds. The a symmetric unit consists of two partly disordered siloxane molecules and one water molecule. The structure of the bilayers is virtually the same at 163 K and room temperature, but the stacking of the bilayers is different. The Si-O-Si bond angles at low temperature are significiantly smaller than at room temperature.