¹H and ¹³C NMR assignments of the three dicyclopenta-fused pyrene congeners

Abstract

Complete ¹H and ¹³HC NMR assignments of the (di-)cyclopenta-fused pyrene congeners, cyclopenta[cd]- (2), dicyclopenta[cd,fg]- (3), dicyclopenta[cd,jk]- (4) and dicyclopenta[cd,mn]pyrene (5), respectively, are archieved using two-dimensional (2D) NMR spectroscopy. The experimental ¹³C chemical shift assignments are compared with computed ab initio CTOCD-PZ2/6-31G** ¹³C chemical shifts; a satisfactory agreement is found. Substituent-induced chemical shifts in the pyrene core induced by annelation of cyclopenta moieties are discussed. Effects of dicyclopenta topology on electric structure are illustrated for 3-5.