Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The ¹H, ¹³C and ¹⁵N NMR spectra have been measured of coupling products of benzenediazonium salts with nitromethane, nitroethane, 1-nitropropane, 2-nitroethanol and of their sodium salts, and the chemical shifts have been unambiguously assigned. The coupling products have been found to exist only in their hydrazone tautomeric forms. Stereospecific behaviour of the coupling constants ²J(¹⁵N,¹H) and ²J(¹⁵N,¹³C) in the ¹⁵N isotopomers and NOESY have been used to differentiate between the E and Z geometrical isomers. The above-mentioned compounds exist as Z isomers in deuteriochloroform and predominantly (>95%) as E isomers in dimethyl sulfoxide, while the sodium salts are present only as E isomers in dimethyl sulfoxide.

Keywords: 1-Nitroaldehyde phenylhydrazones; ¹H, ¹³C and ¹⁵N NMR; E/Z isomerism.