Photoinitiated charge transport in supramolecular assemblies of a 1,7,N,N'-tetrakis(zinc porphyrin)-perylene-3,4:9,10-bis(dicarboximide).
We report the synthesis and photophysical characterization of a multichromophore array, (Z3PN)4PDI, consisting of four zinc 5-phenyl-10,15,20-tri(n-pentyl)porphyrins (Z3PN) attached to the 1,7,N,N'-positions of perylene-3,4:9,10-bis(dicarboximide) (PDI). The dynamics of energy and charge transport within this system were compared to those of two model compounds, N,N'-(Z3PN)2PDI and 1,7-(Z3PN)2PDI. The symmetry of the lowest unoccupied and highest occupied molecular orbitals of PDI results in significantly different electronic couplings between Z3PN and PDI when they are connected at the 1,7-positions vs the N,N'-positions of PDI. This results in two distinct pathways for electron transfer in (Z3PN)4PDI. Using a combination of metal-ligand binding with the bidentate ligand 1,4-diazabicyclo[2.2.2.]octane (DABCO) and pi-pi stacking, (Z3PN4)PDI forms a supramolecular assembly, [[(Z3PN)4PDI]2-DABCO4]2, in toluene solution. The structure of this hierarchical assembly is characterized with the use of solution-phase X-ray scattering techniques and demonstrates both efficient light harvesting and facile charge separation and transport using multiple pathways.
Kelley
Richard F
RF
Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208-3113, USA.
Shin
Won Suk
WS
Rybtchinski
Boris
B
Sinks
Louise E
LE
Wasielewski
Michael R
MR
D007094:Imides / Q000737:chemistry*; D008665:Metalloporphyrins / Q000737:chemistry*; D008958:Models, Molecular; D010569:Perylene / Q000737:chemistry; D010777:Photochemistry; D012542:Scattering, Radiation; D013057:Spectrum Analysis; D013816:Thermodynamics; D014965:X-Rays; D015032:Zinc / Q000737:chemistry*
D007094:Imides; D008665:Metalloporphyrins; D010569:Perylene; D015032:Zinc