Cooperative association of pyrazoles and phenols: A versatile binary system

Abstract

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⋯π pyrazole hydrogen bonding was essential for the structure of the resorcinol complex.