Self-assembly of sandwich-type (phthalocyaninato)(porphyrinato) europium double-decker complexes: Effects of hydrogen bonding on intermolecular stacking mode and morphology of self-assembled nanostructures

Two novel sandwich-type (phthalocyaninato)(porphyrinato) europium double-decker complexes, namely Eu(Pc)[(NHC8H17)PP] (1) and Eu(Pc)[(NHC8H17)(4)PP] (2), have been designed and synthesized. Their self-assembly properties, in particular the effect of the numbers of octylaminophenyl groups on the morphology of self-assembled nanostructures of these double-decker complexes, have been comparatively and systematically studied. Depending mainly on the hydrogen bond between one octylaminophenyl group at mesa-attached phenyl group of porphyrin ligand in 1 and one aza-nitrogen atom of the phthalocyanine ring in the neighboring molecule of 1, 1 self-assembled into nano-rods with J-type aggregation. In good contrast, introduction of four octylaminophenyl groups onto the mesa-attached phenyl groups of the porphyrin ligand in 2, induces more N-H center dot center dot center dot N hydrogen bonds between neighboring molecules of 2, induces the formation of nano-sheets with H-type aggregation. These results clearly imply the effective influence of hydrogen bond numbers on the molecular stacking mode and the morphology of the assembled nanostructures. (C) 2014 Elsevier Ltd. All rights reserved.