Low Energy Excitations and Emissions using Mechanically Interlocked Fluorophores

NU 2020-039

INVENTORS
J Fraser Stoddart*
Amine Garci
Yassine Beldjoudi

ABSTRACT
Collisional intermolecular interactions between excited states form short-lived dimers and complexes that lead to the emergence of excimer/exciplex emission of lower energy, a phenomenon which must be differentiated from the photoluminescence (PL) of the monomeric molecules.  Although the utilization of noncovalent bonding interactions leading to the generation of excimer/exciplex PL has been investigated extensively, precise control of the aggregates and their persistence at very low concentrations remains a rare phenomenon.   In the search for a fresh approach, Northwestern researchers sought to obtain excimer/exciplex PL from permanent superstructures by incorporating anthracene units into pyridinium-containing mechanically interlocked molecules (MIMs).  They developed a method to generate low energy excitations and emissions using mechanically interlocked fluorophores, overcoming standard procedures utilized for chemical modifications of fluorophores to tune their electronic properties.  Further, their ability to achieve persistence of the low energy (exciplex) fluorescence at low  concentrations, combined with the water solubility of the catenane, are crucial to decrease the cytotoxicity for bioimaging.

APPLICATION

  • Sensing
  • Bioimaging
  • Energy Storage
  • Electronic Devices

ADVANTAGES

  • Persistent exciplex photoluminescence at low concentrations
  • Precise control of the fluorophores
  • Low energy emissions for bioimaging
  • Water solubility arises from the cationic character of the catenane
  • Low cytotoxicity
  • Multi-electron redox process

PUBLICATION
Garci A, Beldjoudi Y, Kodaimati M, Hornick J, Nguyen M, Cetin M, Stern C, Roy I, Weiss E and Stoddart JF (2020) Mechanical-Bond-Induced Exciplex Fluorescence in an Anthracene-Based Homo[2]catenane. JACS. 142: 7956-7967.  

IP STATUS
A US patent application has been filed.

Patent Information: