Anion Binding with Biphenyl-bis-Urea Derivatives: Solution and Solid-State Studies

In this work, we have synthesized and characterized bis-urea derivatives 1-3, featuring a biphenyl spacer, and studied their anion binding properties in DMSO solution and in the solid state. In solution, 1:1 complexes were observed with association constants K values in the 103 – 104 M-1 range with a general preference for acetate over dihydrogenphosphate for all three receptors. We were also able to obtain and characterize by X-ray diffraction on single crystals ten receptor-anion complexes including acetate, dihydrogenphosphate, but also monohydrogenphosphate, halides and the nitrate ion. Linear (anion-receptor)n arrays, porous frameworks and non-centrosymmetric structures were observed and described in details.