Novel pi-Conjugated Systems

 

Extended pi-electron systems, such as polycyclic (hetero)aromatic molecules and conjugated polymers, often possess a spectrum of special electronic and optical properties. Non-linear optical effects, efficient light emission upon electrical or optical stimulation, electrical conductivity (including superconductivity) and magnetism have all been demonstrated in such organic materials. Tuning these properties, their tailoring to specific applications, and, most of all, finding new unexpected properties, is one of the main targets of our research.

Below are a few examples of conjugated molecular and polymeric systems synthesized in our lab.

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Through making such molecules and characterizing their optoelectronic properties we are trying to test the existing paradigms and challenge the misconceptions. Below are some questions that we have been addressing in the recent past:

  • How low HOMO-LUMO gaps can be realized in a stable organic molecule and what would be the properties of such molecule?
  • How does the topology of pi-conjugation (linear vs star-like or cross-like vs fully two-dimensional) affects the molecular properties?
  • What defines the fluorescence quantum yield in organic molecules?
  • How do heteroatoms affect the conductive and emissive properties of pi-conjugated materials?
  • How does the length and parity of alkyl chains affects the packing of pi-conjugated molecules and their conducting properties?

While the nature of this research primarily involves synthesis of new molecular structures, the students involved in such studies should expect a highly cross-disciplinary training, including DFT calculations, electronic spectroscopy, electrochemistry and spectroelectrochemistry, etc.

Recent papers:

Donor-Acceptor Intermediates and Low-Bandgap Polymers by Electropolymerization of Thienoazaborines,
O. Lukoyanova, M. Lepeltier, M. Laferriere, D. F. Perepichka*, Macromolecules 2011, in press.

New azaborine-thiophene heteroacenes,
M. Lepeltier, O. Lukoyanova, A. Jacobson, D.F. Perepichka*, Chem. Comm. 2010, 7007-7009.

New Highly Emissive Thienylene-Vinylene Oligomers and Co-Polymers for Organic Electronics,
S. Jeeva, O. Lukoyanova, A. Karapanayiotis, A. Dadvand, F. Rosei, D.F. Perepichka*, Adv. Funct. Mater. 2010, 20, 20, 1661-1669.

Synthesis, Polymerization and Unusual Properties of New Star-Shaped Thiophene Oligomers,
T. Taerum, O. Lukoyanova, R. Wylie, D. F. Perepichka*, Org. Lett. 2009, 11, 3230-3233.

Towards crystal engineering of solid state polymerization in dibromothiophenes,
M.Lepeltier, J.Hiltz, T.Lockwood, F.Belanger-Gariepy, D.F.Perepichka, J.Mater.Chem. 2009, 19, 5167-5174.

A New Structural Motif in Thienoacene Semiconductors: Synthesis, Structure and Properties of Tetrathienoanthracene Isomers,
J. L. Brusso, O. Hirst, A. Dadvand, S. Ganesan, F. Cicoira, C. M. Robertson, R. T. Oakley, F. Rosei, D. F. Perepichka, Chem. Mater. 2008, 20, 2484-2494.

Combining High Electron Affinity and Intramolecular Charge Transfer in Nitrofluorene - 1,3-Dithiole Push-Pull Diads,
D. F. Perepichka, I. F. Perepichka, O. Ivasenko, A J. Moore, M. R. Bryce, L. G. Kuzmina, A.S. Batsanov, N.I. Sokolov, Chem. Eur. J. 2008, 14, 2757-2770.

A new simple synthesis of poly(thiophene-methine)s,
Md.B.Zaman, D.F.Perepichka, Chem. Commun. 2005 , 4187-4189.

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