Cooperative association of pyrazoles and phenols: A versatile binary system

The ability of self-complementary H-bond donor/acceptor phenol (OH/O) and pyrazole (NH/N) molecules for cooperative association allowed the developing of a range of binary compounds, in which the molecular counterparts are integrated by hydrogen bonding. Complexes involving either monofunctional 3,5-dimethylpyrazole and phenol and polyfunctional 3,3',5,5'-tetramethyl-4,4'-bipyrazole, hydroquinone and phloroglucinol are based on mixed phenol-pyrazole chains. They reveal common features allowing high level of control over the entire connectivity and dimensionality. Unprecedented NH...pi pyrazole hydrogen bonding was essential for the structure of the resorcinol complex.