Synthesis and NMR study of new derivatives of [2,2′-bipyridyl)-3,3′-diol and [2,2′-bipyridyl]-3-ol

Seven compounds, forming intramolecular hydrogen bonds, mostly non-symmetric derivatives of [2,2'-bipyridyl]-3,3'-diol (BP(OH)(2)) were synthesised. Six of them were chosen for the further analysis. It was proved that the electron-donating (CH3) or electron withdrawing (COOH. COOCH3) substituent introduced next to the reactive proton transfer site (N-atom) may change the parameters of hydrogen bridge in a predictable way. The ab initio (GIAO-CHF/DZP//6-31 G**) and semiempirical (PM3) calculations of the ground state were performed. The molecular geometries, Mulliken net charges, NMR shielding constants were compared with some experimental data. In particular. the N-15 nuclear magnetic resonance was used to compare the strength of two internal H-bonds of the molecule. (C) 2000 Elsevier Science B.V. All rights reserved.