We report octupolar trisporphyrin conjugates, derived from the symmetrical functionalization of a triphenylamine core with three ethynylporphyrin wings, exhibiting largely enhanced two-photon absorption (TPA) compared to the porphyrin monomers. Octupolar trisporphyrin conjugate tris-H2P was synthesized by the Pd(0)-catalyzed Sonogashira cross-coupling reaction of tris(4-iodophenyl)amine with 5,10,15-tri-(p-tolyl)-20-ethynylporphyrin, and fully characterized by various spectroscopic methods and elemental analysis. The optimized geometry of tris-H2P obtained by semi-empirical AM1 calculations reveals that tris-H2P adopts a propeller-shaped structure. Our photophysical studies strongly manifest that the trisporphyrin conjugates are promising octupolar fluorophores with effective π-conjugation over the porphyrin wings through the octupolar core. The trisporphyrin conjugates exhibit much larger TPA cross-section values in comparison with the monomers; the TPA cross-section σ(2) value of tris-ZnP (11,800 GM) exceeds that of mono-ZnP (630 GM) by about 20 times.
Bibliographical noteFunding Information:
This work was supported by the Korea Research Foundation (KRF-2005-202-C00184). The work at Yonsei University was supported by the Star Faculty Program of the Ministry of Education, Korea for Human Resources. We thank Professor Jin Yong Lee for calculating optimized geometry of tris-H 2 P .
All Science Journal Classification (ASJC) codes
- Drug Discovery
- Organic Chemistry