Supramolecular ssDNA templated porphyrin and metalloporphyrin nanoassemblies with tunable helicity

Gevorg Sargsyan, Brian M. Leonard, Jan Kubelka, Milan Balaz

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Free-base and nickel porphyrin-diaminopurine conjugates were formed by hydrogen-bond directed assembly on single-stranded oligothymidine templates of different lengths into helical multiporphyrin nanoassemblies with highly modular structural and chiroptical properties. Large red-shifts of the Soret band in the UV/Vis spectroscopy confirmed strong electronic coupling among assembled porphyrin-diaminopurine units. Slow annealing rates yielded preferentially right-handed nanostructures, whereas fast annealing yielded left-handed nanostructures. Time-dependent DFT simulations of UV/Vis and CD spectra for model porphyrin clusters templated on the canonical B-DNA and its enantiomeric form, were employed to confirm the origin of observed chiroptical properties and to assign the helicity of porphyrin nanoassemblies. Molar CD and CD anisotropy g factors of dialyzed templated porphyrin nanoassemblies showed very high chiroptical anisotropy. The DNA-templated porphyrin nanoassemblies displayed high thermal and pH stability. The structure and handedness of all assemblies was preserved at temperatures up to +85 °C and pH between 3 and 12. High-resolution transition electron microscopy confirmed formation of DNA-templated nickel(II) porphyrin nanoassemblies and their self-assembly into helical fibrils with micrometer lengths.

Original languageEnglish
Pages (from-to)1878-1892
Number of pages15
JournalChemistry - A European Journal
Volume20
Issue number7
DOIs
Publication statusPublished - 2014 Feb 10

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

Cite this