H-1 AND C-13 NMR-STUDIES OF INTRAMOLECULAR HYDROGEN-BONDS IN SUBSTITUTED 2,6-BIS(DIETHYLAMINOMETHYL)PHENOL DI-N-OXIDES AND THEIR MONOTETRACHLOROAURATES

Ten substituted 2,6-bis(diethylaminomethyl)phenol di-N-oxides (2,6-DNO) and their monotetrachloroaurates were studied by H-1 and C-13 NMR spectroscopy. With the 2,6-DNO, the chemical shift of the hydrogen-bonded proton demonstrates that equilibria occur between the non-polar and polar structures of the intramolecular hydrogen bond (OH ... ON reversible O- ... H+ON) and between a homoconjugated intramolecular hydrogen bond (NO ... H+ ... ON). With the monotetrachloroaurates of the 2,6-DNO, an intramolecular hydrogen-bonded system is formed in which a collective proton motion proceeds and which shows large proton polarizability. The H-1 NMR chemical shifts of the hydrogen-bonded protons become first stronger and after a maximum again weaker. The C-13 NMR results prove that this method is a useful tool for studies of molecular hydrogen bonds in which collective proton motion occurs.