1H and 13C NMR spectra of (Z)-N-(o-hydroxy-benzylidene)-p-x-phenylamine N-oxides and (Z)-N-(2-hydroxy-1-naphthylmethylene)-p-X-phenylamine N-oxides

✍ Scribed by N. Arumugam; P. Manisankar; S. Sivasubramanian; D. A. Wilson

• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 380 KB
• Volume: 23
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260230407

✦ Synopsis

Substituent effects on the 'H and =C chemical shifts of ( z ) -N -( ~h y d r o ~~~t i d e n e ) -p X -p h e n y l ~e N-oxides [(z)-a-(~hydroxyphenyl)-N-pX-phenyl nitrones] and (z)-N-(2-hy~oxy-l-naphthy~ethylene)-pX-phenylamine N-oxides [(z)-a-(2-hydro~-l-naphthyl)-N-pX-pX-phenyI nitrones] have been obtained. A combmation of SFDOR and NOE methods was necessary for complete assignment of signals in the naphthalene series. Correlations have been found between the chemical shifts of varions protons and carbons and Hammett u parameters and Swain and Lupton F and R parameters. With both series of compounds a 6xed conformation, due to intramolecular hydrogen bonding, is observed which &ecis the polarity of the drone group compared with that in a,N-diphenyl nitrone. Reduced through-resonance between aryl M g s via the nitrone function was found. This may be attributed to the a-aryl ring and the nitmne group being held out of coplanarity by the hydrogen bond.