Molecular and crystal structure of an amphiphile: 4'-propoxybiphenyl-4-methyl-N,N-dimethylamineoxide dihydrate

A novel amphiphile, 4'-propoxybiphenyl-4-methyl-N,N-dimethylamineoxide, has been synthesized, crystallized (P2(1)/a, a = 9.084 A, b = 8.911 A, c = 22.460 A, beta = 96.224 degrees) and its crystal structure was determined. The amphiphile forms a bilayer in which the amineoxide oxygen of each molecule binds two water molecules. In the hydrophobic part of the bilayer the biphenyls form edge-to-face contacts, in the polar layer there is a hydrogen bonding network. The potential use of the compound as a detergent for membrane proteins has been demonstrated and the relevance of the amineoxide hydrate for other detergents discussed.