1,8-Dihydroxy Naphthalene-A New Building Block for the Self-Assembly with Boronic Acids and 4,4'-Bipyridine to Stable Host-Guest Complexes with Aromatic Hydrocarbons.

The new Lewis acid-base adducts of general formula X(nad)B←NCH-CHN→B(nad)X [nad = 1,8-OCH X = CH (), 3,4,5-F-CH ()] were synthesized in high yields via reactions of 1,8-dihydroxy naphthalene [nadH] and 4,4'-bipyridine with the aryl boronic acids CHB(OH) and 3,4,5-F-CHB(OH), respectively, and structurally characterized by multi-nuclear NMR spectroscopy and SCXRD. Self-assembled H-shaped Lewis acid-base adduct proved to be effective in forming thermally stable host-guest complexes, × solvent, with aromatic hydrocarbon solvents such as benzene, toluene, mesitylene, aniline, and -, -, and -xylene. Crystallographic analysis of these solvent adducts revealed host-guest interactions to primarily occur via π···π contacts between the 4,4'-bipyridyl linker and the aromatic solvents, resulting in the formation of 1:1 and 1:2 host-guest complexes. Thermogravimetric analysis of the isolated complexes × solvent revealed their high thermal stability with peak temperatures associated with the loss of solvent ranging from 122 to 147 °C. , when self-assembled in an equimolar mixture of -, -, and -xylene (1:1:1), preferentially binds to -xylene. Collectively, these results demonstrate the ability of 1,8-dihydroxy naphthalene to serve as an effective building block in the selective self-assembly to supramolecular aggregates through dative covalent N→B bonds.