Novel layer- and channel-type anionic host lattices built of thiourea, 2-thiouracil anion and water

Conformation and Visual Distinction between Urea and Thiourea Derivatives by an Acetate Ion and a Hexafluorosilicate Cocrystal of the Urea Derivative in the Detection of Water in Dimethylsulfoxide

Structures of different solvates and solute-solvent interactions of 4-(3-(4-nitrophenyl)urido)benzoate (L ₁ ) and methyl-4-(3-(4-nitrophenyl)thiourido)benzoate (L ₂ ) with different solvents are analyzed. The solution of L ₁ with tetrabutylammonium acetate (TBAA) in dimethylsulfoxide (DMSO) is colorless, but a similar solution of L ₂ with TBAA is orange. On the other hand, respective solutions of these urea and thiourea derivatives with tetrabutylammonium fluoride (TBAF) in DMSO are orange. Urea derivative L ₁ facilitates the reaction of TBAF with glass to form tetrabutylammonium hexafluorosilicate, which on further interaction with L ₁ forms cocrystal 2L ₁ ·(TBA)₂SiF₆. Reorganization of hydrogen-bonded self-assembly of 2L ₁ ·(TBA)₂SiF₆ in DMSO caused by water is established by a dynamic light scattering study. With an increase in the amount of water in the solution, visual color changes from orange to colorless, and the color changes are reversed upon the addition of a dehydrating agent such as molecular sieves. Solvates of L ₁ with DMSO, dimethylformamide (DMF), and dimethylacetamide are quasi-isostructural. The respective self-assembly of these solvates differs due to orientations of aromatic rings and the carbomethoxy group across the thioamide/amide bond. Significant differences in self-assemblies of the respective DMSO solvate of L ₁ and L ₂ are observed; self-assembly of the former has dimeric subassemblies as repeat units, whereas the latter has monomeric subassemblies. DMF solvates of L ₁ and dimethylacetamide of L ₁ are built by dimeric subassemblies to form self-assembled structures, but these subassemblies differ in the orientation of the carbomethoxy group across the urea units.

Enclathration of morpholinium cations by Dianin's compound: salt formation by partial host-to-guest proton transfer

In spite of partial deprotonation upon inclusion of morpholine, Dianin's compound maintains its well-known clathrate structure in the solid state.