DANA BLAIR:  Synthesis of Chiral Radical Molecules

  
     
 

Objective:  Synthesize chiral one-dimensional organic magnets and identify their chemical and physical properties.

  
     
 

Lab:  Dr. Andrzej Rajca

  

 

 

RESEARCH RATIONALE Radical  molecules are typically intermediates in many organic reactions and due to their reactivity they are seldom found in nature as stable molecules.  Synthesizing chiral-specific stable radicals will give researchers the ability to utilize certain properties of radicals, like magnetism, to produce useful plastics and polymers.
RESEARCH BACKGROUND Radicals are defined as molecules that contain unpaired electrons.  Although Lewis theory (see tutorial) states that atoms/molecules strive for stability by gaining or losing electrons to fill the valence shell with 8 electrons, in certain situations this is not the case. There are some molecules that exist without filling the valence shell, like the diatomic molecule oxygen. Due to the lone electron(s) in bonding (or anti-bonding) orbitals the radical molecules typically have magnetic properties, called paramagnetism.
  The instability of most radicals is typically of that with intermediates in free radical chain reactions.  Most reactions that utilize radicals are required by synthesizing an initiator radical during the Initiation phase. The difficulty is being able to isolate these radicals for study for other synthetic processes.  Studies that incorporate the formation of radical ions are beginning to find their way into application and show promise in industrial synthetic processes.
   So why study radicals...... Dr. James Tanko put some perspective on his research by creating his Top Ten List.
 

 

RESEARCH PROCEDURES Dana's research will include the synthesis of an organic chiral diradical molecule where both racemate and pure enantiomer forms will be produced. The diradical molecules will be ligated by metal atoms to form organic complexes. It is the formation of the metal/organic radical that produces the magnetic properties.  The goal of the research is create these complexes where the metal contains unpaired electrons yielding high spin materials

Here is Dana working in the fume hood.  She is synthesizing the precursors for her diradical molecule.

The stable diradical molecule will then be bound to the metal atom.
 

 
The products of Dana's synthesis steps are analyzed by performing a Thin Layer Chromatography.  A thin film of silica gel is spread over a small piece of glass and blotted with a drop of her products.  The bottom edge of the glass is placed in a solvent and the products are allowed to separate by mass and affinity to the silica. 

 

 

Here is a sample of the crystals Dana was able to obtain from her reactions.  These crystals may have the properties the lab is looking for. 
 

 
 

 

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