Optics + Photonics Research Area Affiliations

• Optical Materials
• Biophotonics

Research Summary

Dr. Bunz's research is centered on the investigation of the electronic properties of conjugated polymer, oligomer, or molecular materials; carbon rich organometallics; polyaryleneethynylenes (PAEs); physical Characterization and materials science; and biogenic polyaryleneethynylenes.

Biographical Sketch

Research in the Bunz group is concentrated on conjugated molecules. All aspect of conjugated, i.e. unsaturated, carbon-rich compounds are covered.

• Investigation of the electronic properties of conjugated polymer, oligomer, or molecular materials, for applications in novel semiconducting devices, such as light-emitting diodes, photovoltaic components, or field-effect transistors.
  
  
• Carbon rich organometallics: Utilizing ferrocene and cyclobutadiene(cyclopentadienyl)cobalt nuclei as center a series of highly alkynylated, nanoscopic and fully unsaturated compounds were prepared. Some of these compounds give novel carbon materials upon pyrolysis.
  
  
• Polyaryleneethynylenes (PAEs) : In recent years we have made inroads into the effective synthesis of PAEs utilizing either acyclic diyne metathesis (ADIMET) or Pd-catalyzed couplings of aromatic diynes to aromatic diiodides. The PAEs have a range of different but very attractive chromic, conducting, optical and emissive properties. These properties that can be harnessed in modern device applications that include but are not restricted to thin film transistors, light emitting diodes, and sensory gadgets.
  
  
• Physical Characterization and materials science : An important aspect of our work is the understanding of the structure property relationship of the PAEs we make. Characterization by powder diffraction, transmission electron microscopy, differential scanning calorimetry, thermogravimetry and UV-vis and fluorescence spectroscopies are standard and performed by us. In collaborations with engineers and physicists device applications such as LEDs and TFTs are developed.
  
  
• Biogenic polyaryleneethynylenes : Bioterrorist threats necessitate new and simple analytical tool for the detection of pathogenic substances, bacteria and toxins. The dramatic chromicity of the PAEs makes them an excellent platform for the attachment of biomolecules such as sugars, small peptides and oligonucleotides. The resulting PAEs are highly sensitive in the detection of complementary biogenic molecules and the extension of this concept will result in applications beyond the detection of disease agents and will furnish nano-architectures that are otherwise not accessible.
  

Representative Publications

M. Laskoski, W. Steffen, J. G. M. Morton, M. D. Smith, U. H. F. Bunz, Synthesis and explosive decomposition of organometallic dehydro[18]annulenes: An access to carbon nanostructures, J. Am. Chem. Soc. 2002 ,124 , 13814-13818.

G. Brizius, U. H. F. Bunz, Increased activity of in situ catalysts for alkyne metathesis, Org. Lett. 2002 ,4, 2829-2831.

S. M. Waybright, K. McAlpine, M. D. Smith, U. H. F. Bunz, Organometallic dendrimers based on (tetraphenylcyclobutadiene)cyclopentadienylcobalt modules, J. Am. Chem. Soc. 2002 ,124 , 8661.

J. N. Wilson, W. Steffen, T. G. McKenzie, G. Lieser, M. Oda, D. Neher, U. H. F. Bunz, Chiroptical properties of poly(paraphenyleneethynylene) copolymers in thin films: Large g-values, J. Am. Chem. Soc. 2002 ,124 , 6830-6831.

M. Laskoski, W. Steffen, J. G. M. Morton, M. D. Smith, U. H. F. Bunz, Synthesis and structural characterization of organometallic cyclynes: novel nanoscale, carbon-rich topologies, Angew. Chem. 2002 ,41 , 2378-2381.

N. G. Pschirer, D. M. Ciurtin, M. D. Smith, U. H. F. Bunz, H.-C. zur Loye, Noninterpenetrating square-grid coordination polymers of the dimensions 25x25 Å2 prepared by using N'N-type ligands: The first chiral square-grid coordination polymer, Angew. Chem. 2002 ,41 , 583-586.

U. H. F. Bunz, Alkyne metathesis: access to high molecular weight dialkyl(polyparaphenyleneethynylene)s: A case study for the interplay of synthesis, spectroscopy, and materials science, Acc. Chem. Res. 2001 ,34 , 998.

M. I. Sluch, A. Godt, U. H. F. Bunz, M. A. Berg, Excited-state dynamics of oligo(p-phenylene-ethynylene): quadratic coupling and torsional motions, J. Am. Chem. Soc. 2001 ,123 , 6447.

M. Laskoski, G. Roidl, M. D. Smith, U. H. F. Bunz, Concave butterfly-shaped organometallic hydrocarbons? Angew. Chem. 2001 ,40 , 1460-1463.

S. Waybright, C. P. Singleton, K. Wachter, C. J. Murphy, U. H. F. Bunz, Oligonucleotide directed assembly of materials: defined oligomers, J. Am. Chem. Soc. 2001 ,123 , 1828.

G . Brizius, N. G. Pschirer, W. Steffen, K. Stitzer, H.-C. zur Loye, U. H. F. Bunz, Alkyne metathesis with simple catalyst systems: efficient synthesis of conjugated polymers containing vinyl groups in main or side chain, J. Am. Chem. Soc. 2000 ,122 , 12435.

U. H. F. Bunz , Polyaryleneethynylenes: syntheses, properties, structures, and applications, Chem. Rev. 2000 ,100 , 1605.

L. Kloppenburg, D. Song, U. H. F. Bunz, Alkyne Metathesis with Simple Catalyst Systems: Poly(p-phenylenethynylene)s, J. Am. Chem. Soc. ,1998 ,120 , 7973.

C. E. Halkyard, M. E. Rampey, L. Kloppenburg, S. L. Studer-Martinez, and U. H. F. Bunz, Evidence of Aggregate Formation for 2,5-Dialkylpoly(p-phenyleneethynylenes) in Solution and Thin Films, Macromolecules 1998 ,31 , 8656.