Effect of methyl substituent in the fjord region on the conformational stability of aza[5]helicenes

Abstract

Few derivatives of aza[5]helicenes were synthesized and characterized. Introduction of methyl group in the fjord region of aza[5]helicene gives sufficient conformational rigidity resulting in the formation of stable, resolvable enantiomers. The analysis of dimethyl aza[5]helicene on chiral HPLC columns indicate the presence of resolvable isomers. The compounds 1 and 15were further characterized by single crystal X-ray diffraction and computational analysis while their photophycial properties were studied.