Effect of alkyl substituents on the hydrogen bonding and molecular structures of benzophenylhydroxamic acids

Abstract

The effect of alkyl substitutents on the C-phenyl and/or the N- phenyl ring of benzophenylhydroxamic acids on their molecular structure and hydrogen bonding has been investigated. The predominant configuration in CHCI₃ is determined by steric and electronic effects. Substituents on the C-phenyl ring favour the <em>cis</em> configuration, while substituents on the N-phenyl ring favour a <em>trans</em> configuration. These can be rationalised on the basis of electronic effects. Bulky substituents in the C- phenyl ring give rise to a mixture of <em>cis</em> and <em>transforms</em> due to steric factors. When substituents are present on the C-phenyl ring and N-phenyl ring the <em>trans</em> configuration is preferred.