Synthesis and Properties of Low-Bandgap Zwitterionic and Planar Conjugated Pyrrole-Derived Polymeric Sensors. Reversible Optical Absorption Maxima from the UV to the Near-IR.
Abstract
Described are the polymerizations of three new dibrominated carbonyl-stabilized yield monomers using copper-bronze in DME to afford polymers that are soluble in common solvents and have unique optical and electronic properties. The first monomer is a zwitterionic N- (butyl)pyrrolinium oxide derivative which, upon polymerization, gives a polymer that has a strong optical absorbance at 520 nm in CCl4. An inter-unit ionic interaction is proposed to explain this large red-shifted band. Bronsted bases and Lewis bases induce a reversible structural change in the polymer to give bathochromic shifts from the visible to the near-IR spectral region. Upon mild reduction of the zwitterionic polymer with Pd/C and H2 (1 atm), some of the extended conjugation is lost, but a polymer forms that has an enormous optical absorption maximum range from the near-UV (290 nm) to the near-IR (886 nm) depending on the solvent or hydroxide concentration. A sample of the reduced polymer can be dispersed in plasticized poly(vinyl chloride). The flexible polymer composite reversibly changes from dark blue-brown in aqueous sodium hydroxide to bright yellow-orange in aqueous HCl. The second monomer, a zwitterionic N-(dodecyl)pyrrolinium oxide derivative, was also synthesized in three steps from pyrrole, and upon polymerization, gives rise to a polymer which also responds reversibly towards Bronsted and Lewis bases. This polymer can be solution cast into flexible-free standing films. jg p.2
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 07, 1995
- Accession Number
- ADA296388
Entities
People
- James Tour
- Thorsen W. Brockmann
Organizations
- University of South Carolina