Anion complexation, transport and structural studies of a series of bis-methylurea compounds

Abstract

A new family of bis-methylureas () have been synthesised and their ability to bind anions both in solution and in the solid state and to transport them through lipid membrane have been studied. From the solid state studies it has emerged that various conformations can be adopted by the receptors allowing the isolation of complexes of different stoichiometries (from 1 : 1 to 1 : 3). The transport studies highlighted the possibility to use bis-methylureas to mediate Cl(-) transport across membranes.

Anion Recognition by a Bioactive Diureidodecalin Anionophore: Solid‐State, Solution, and Computational Studies

“…The affinity is higher than those previously observed for similar systems . H 2 PO 4 − is also bound more strongly by 1 than by other compounds with the same binding motif …”

“…The measureda ffinitiesa re one to two orders of magnitude higher than those for comparable systems under the same conditions. [3e19, 21,22,24] Considering tetrahedral anions, SO 4 2À is very strongly bound by 1,a so ften found for this substrate. [3d] Indeed the 1 HNMR experimentsi ndicatet he binding of as econd anion to form 1·(SO 4 2À À ) 2 ,d espite the Coulomb repulsion between the two anions.…”

“…Note that whereas K a for 1⋅Br − in DMSO is only 70 m −1 , other binding studies on Br − with urea‐ or thiourea‐based receptors in DMSO generally gave lower affinities, unless Br − was fully encapsulated in a cage . This is not to say that 1 is a poor receptor for Cl − ; its affinity is still 3–35 times higher than those found for other urea‐based anion receptors with multiple (nitrophenyl)urea groups in DMSO . However, it seems that the larger Br − is a better fit than Cl − .…”

Anion Receptor Chemistry

“…Olivari et al 84 reported a series of bismethylurea compounds 168-169 with aromatic substituents (Figure 57). Although both trifluoromethyl (CF 3 ) and nitro (NO 2 ) are electron-withdrawing groups, the fluorination from CF 3 substituents improves the lipophilicity of the compounds.…”

A new class of silica-supported chromo-fluorogenic chemosensors for anion recognition based on a selenourea scaffold

“…However, in this scenario, and, to the best of our knowledge, examples of selenourea-based anion sensors have never been reported in the literature to date despite selenoureas are interesting organoseleno compounds that show anticancer activity, antioxidant properties, enzyme inhibition, and DNA binding properties. [16][17][18][19][20] Taking these concepts into account and following our interest in anion recognition and sensing [21][22][23][24][25] we decided to explore the potential use of selenoureas as a new scaffold for the design of anion chemosensors.In particular, here, we describe the ability of the asymmetric 1-(4-methyl-2-oxo-2H-chromen-7-yl)-3-phenylselenourea (L) to act as a colorimetric and/or fluorescent sensor for S 2-and CNrecognition. L was obtained according to the reaction shown in Scheme 1.…”