engleski

Complexation properties of aromatic diureas

The design of molecules which are capable to recognize and bind target anions is a vibrant area of modern research. Systematic research of anion coordination during the last few decades introduced a vast number of receptors for negatively charged species, mainly based on the binding functionalities equipped with hydrogen bond donors. The urea group is often used in such receptors due to its stability in acidic environment and the ability to form strong hydrogen bonds with certain anions. However, it has become evident that compounds containing a single urea moiety lack selectivity and rather rarely allow specific anion recognition. On the other hand, by linking two urea moieties via benzene, rigidity of the binding site is induced and significant increase in selectivity towards anions and stability of corresponding complexes can be achieved. In this work we have synthesized new phenyl diurea receptors (1a-d) and investigated both steric and resonance effects of the substituents on their complexation properties. In order to quantify binding affinities of anion receptors 1a-d towards several anions and to get a detailed insight into the processes occurring in the solutions, NMR and UV-VIS titrations were used.

urea ; complexation ; NMR ; UV

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