title: Morphology controlled self-assembled nanostructures of sandwich mixed (phthalocyaninato)(porphyrinato) europium triple-deckers. Effect of hydrogen bonding on tuning the intermolecular interaction.
abstract: A series of five novel sandwich-type mixed (phthalocyaninato)(porphyrinato) europium triple-decker complexes with different numbers of hydroxyl groups at the meso-substituted phenyl groups of porphyrin ligand 1-5 have been designed, synthesized, and characterized. Their self-assembly properties, in particular the effects of the number and positions of hydroxyl groups on the morphology of self-assembled nanostructures of these triple-decker complexes, have been comparatively and systematically studied. Competition and cooperation between the intermolecular pi-pi interaction and hydrogen bonding in the direction perpendicular to the pi-pi interaction direction for different compounds were revealed to result in nanostructures with a different morphology from nanoleafs for 1, nanoribbons for 2, nanosheets for 3, and curved nanosheets for 4 and to spherical shapes for 5. The IR and X-ray diffraction (XRD) results reveal that, in the nanostructures of triple-decker 2 as well as 3-5, a dimeric supramolecular structure was formed through an intermolecular hydrogen bond between two triple-decker molecules, which as the building block self-assembles into the target nanostructures. Electronic absorption spectroscopic results on the self-assembled nanostructures reveal the H-aggregate nature in the nanoleafs and nanoribbons formed from triple-deckers 1 and 2 due to the dominant pi-pi intermolecular interaction between triple-decker molecules, but the J-aggregate nature in the curved nanosheets and spherical shapes of 4 and 5 depending on the dominant hydrogen bonding interaction in cooperation with pi-pi interaction among the triple-decker molecules. Electronic absorption and XRD investigation clearly reveal the decrease in the pi-pi interaction and increase in the hydrogen bonding interaction among triple-decker molecules in the nanostructures along with the increase of hydroxyl number in the order of 1-5. The present result appears to represent the first effort toward realization of controlling and tuning the morphology of self-assembled nanostructures of sandwich tetrapyrrole rare earth complexes through molecular design and synthesis.
authors.affiliation: Department of Chemistry, Shandong University, Jinan 250100, China.
authors.forename: Guifen
authors.initials: G
authors.lastname: Lu
authors.forename: Yanli
authors.initials: Y
authors.lastname: Chen
authors.forename: Yuexing
authors.initials: Y
authors.lastname: Zhang
authors.forename: Meng
authors.initials: M
authors.lastname: Bao
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Bian
authors.forename: Xiyou
authors.initials: X
authors.lastname: Li
authors.forename: Jianzhuang
authors.initials: J
authors.lastname: Jiang