Structures of N,N′-bis(1,2-dicarba-closo-dodecaboran-1-yl)phenylureas: building blocks for carborane-containing macromolecules

We report the preparation and structural analysis of carborane-containing diphenylureas (1a–c and 2a–c). The secondary ureas (1) exist in trans-conformation. In spite of the bulkiness of the carborane cage, the N-methylated ureas (2) exist in cis-conformation, both in solution and in the solid-state. The results should make it possible to utilize the construction of more complex molecules.