Structure of the adducts methylthiourea: 1,4-dioxane (2:1) and 1,1-dimethylthiourea: morpholine (1:1)

Abstract

Abstract The adducts methylthiourea:1,4-dioxane (2:1) (1) and 1,1-dimethylthiourea:morpholine (1:1) (2) were prepared and their crystal structures determined. In 1, hydrogen bonding involving the methylthiourea molecules leads to the formation of R 2 2 ( 8 ) ${\rm{R}}_2^2(8)$ rings and thence to molecular ribbons parallel to [110]. The dioxane molecules accept hydrogen bonds from the remaining NH groups, and their inversion symmetry means that they connect adjacent methylthiourea ribbons, forming a layer structure parallel to (11̅1). In the packing of 2, dimethylthiourea dimers cannot link to each other because of the blocking effect of their methyl groups, but instead are linked indirectly via morpholine molecules, the NH groups of which are simultaneously hydrogen bond acceptors from the remaining NH function of dimethylthiourea and donors towards the sulfur atom of a neighbouring dimer. The overall effect is to form broad ribbons parallel to the a axis, with the morpholine molecules occupying the peripheral positions. The morpholine oxygen atom of 2 is not involved in classical hydrogen bonds.