[Todos] Seminario Quimica Organica - Prof Maxwell J. Crossley - Mie 27/4- 13hs

[Carola Gallo]

SEMINARIO DE QUIMICA ORGANICA 2011

Mi¨¦rcoles 27 de abril, 13 hs

Aula de Seminario, Departamento de Qu¨ªmica Org¨¢nica, FCEyN

 

Professor Maxwell J. Crossley

School of Chemistry, The University of Sydney, NSW 2006, Australia

 

Ring-annulated Porphyrins for Photochemical Upconversion

 

Ring annulation of the pyrrolic rings of porphyrins leads to very
interesting compounds that behave as ¦Ð-expanded systems. We previously
synthesised tetrakis(quinoxalino)porphyrins, porphyrins that are expanded in
four directions; for example, Pd(II) tetrakisquinoxalinoporphyrin 2 from the
porphyrin 1 by three different routes (Scheme 1).1  These syntheses and
extrapolation of this methodology which allows synthesis of
tetrakis(diaza-anthraceno)porphyrins and other ¦Ð-expanded porphyrin systems
will be described in detail.

Upconversion is the process whereby a stream of light of a given photon
energy is converted into one of a higher energy. Very efficient red to
yellow light upconversion is achieved by triplet-triplet annihilation using
the palladium ¦Ð-expanded porphyrins as sensitizer molecules and rubrene as
the emitter molecule We have demonstrated TTA efficiencies estimated at 60%,
far in excess of the statistical 11.1% limit of singlet formation.2 I will
also report red to green, red to blue, and green to blue upconversion using
other emitters.

 

1.  T. Khoury and M.J. Crossley, Chem. Commun., 2007, 4851. 

2. Y.Y. Cheng, B. F¨¹ckel, T. Khoury, R.G.C.R Clady, M.J.Y. Tayebjee, N.J.
Ekins-Daukes, M.J. Crossley, and T.W. Schmidt, J. Phys. Chem. Lett., 2010,
1,1795-1799.

 

 

 

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