HYDROGEN-BONDS AND A HYDROGEN-BONDED CHAIN IN MANNICH-BASES OF 5,5'-DINITRO-2,2'-BIPHENOL-FT-IR AND H-1-NMR STUDIES

5,5'-Dinitro-3-diethylaminomethyl-2,2'-biphenol (1) and 5,5'-dinitro-3 ,3' bis(diethylaminomethyl)-2,2'-biphenol (2) as well as 5,5'-dinitro- 2,2'-biphenol (3) were synthesized and studied by FT-IR and H-1 NMR sp ectroscopy in acetonitrile or acetonitrile-d(3) solutions, respectivel y, With compound 1 a hydrogen-bonded system with large proton polariza bility is found. In the hydrogen bonds in compound 2 the protons are l ocalized at the N atoms. These hydrogen bonds show no proton polarizab ility. In the protonated compound 2 a very strong homoconjugated O- .. . H+... O- hydrogen bond with large proton polarizability is found, wh ereas two other protons are localized at the N atoms. The deviation of the results obtained with other derivatives of 2,2'-biphenols are cau sed by the larger acidity of the nitro groups. (C) 1997 Elsevier Scien ce B.V.