7-Azaindolyl- and 2,2′-dipyridylamino-functionalized molecular stars with sixfold symmetry: Self-assembly, luminescence, and coordination compounds

Wen Li Jia, Rui Yao Wang, Datong Song, Steven J. Ball, Alastair B. McLean, Suning Wang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


Two novel star molecules functionalized with 7-azaindolyl and 2,2′-dipyridylamino groups have been synthesized. Both molecules possess a sixfold rotation symmetry. Molecule L1 is based on the hexaphenylbenzene core with the formula of hexa[p-(7-azaindolyl)phenyl]benzene, while molecule L2 is based on the hexakis(biphenyl)benzene core with the formula of hexa[p-(2,2′-dipyridylamino)biphenyl]benzene. Both compounds have been characterized by single-crystal X-ray diffraction analyses. Molecule L1 forms extended two-dimensional layered structure, while L2 forms interpenetrating columnar stacks in the solid state, as revealed by X-ray diffraction analyses. Nanowire structures based on columnar stacks through self-assembly of L2 on a graphite surface were revealed by an STM study. Molecules L1 and L2 are capable of binding to metal ions, resulting in unusual structural motifs. Two Ag 1 complexes with the formulae of [(AgNO3)2(L1) (1) and [(AgNO3)3(L1) (2) were isolated from the reactions of AgNO3 with L1. Compound 1 displays extended intermolecular π-π stacking interactions that are responsible for its extended two-dimensional structure in the crystal lattice, Complex 2 has a "bowl" shape and forms polar stacks in the crystal lattice. A Cu II complex with the formula of [{Cu(NO3)2} 6(L2) (3) was isolated from the reaction of Cu(NO3) 2 with compound L2. The six CuII ions in 3 are chelated by the 2,2′-dipyridylamino groups of the star ligand L2. Intermolecular Cu-O (nitrate) bonds lead to the formation of an extended two-dimensional coordination network of 3. Both L1 and L2 are blue luminescent. Their interactions with AgI or CuII cause drastic quenching of emission. In addition, the luminescence of L1 and L2 is sensitive to the presence of protons, which cause a reduction of emission intensity and a red shift of the emission energy.

Original languageEnglish
Pages (from-to)832-842
Number of pages11
JournalChemistry - A European Journal
Issue number3
Publication statusPublished - 21 Jan 2005
Externally publishedYes


  • Luminescene
  • Molecular stars
  • Self-assembly
  • Structure elucidation
  • Supramolecular chemistry

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