Association of phenyldiboronic acids with hydrogen bond acceptors to form hydrogen bonded DD·AA-type complexes: a DFT study

Abstract

Boronic acid is known to form DD·AA, DA·AD, and AA·DD type complexes. In this article, the ability of phenyldiboronic acid to associate with hydrogen bond acceptors (1,8-naphthyridine, 5,6,11,12-tetraazanaphthacene, 2,8a-dihydropyrano[2,3-b]pyran and 4aH-[1,4]dioxino[2,3-b][1,4]dioxine) has been analyzed in light of density functional theory. Stabilization energy and thermochemical analysis predict the feasibility of formation of DD·AA type complexes between phenyldiboronic acid and N–/O–hydrogen bond acceptors. The gas and solvent phase calculations showed that the stabilization energy varies with the size of the association geometry. IR and NMR studies revealed the weakening of the O–H bond during complexation. Complexes with as many as three boronic acids and four hydrogen bond acceptors are studied and are predicted to be stable.