Palladium complexes of perylene diimides: strong fluorescence despite direct attachment of late transition metals to organic dyes.
We prepared the first sigma-bonded metal complexes of widely utilized organic dyes, perylene tetracarboxylic acid diimides (PDIs). These 1,7-dipalladium PDI complexes were synthesized by C-Br oxidative addition of 1,7-dibromo-N,N'-dicyclohexyl PDI (Br2PDI) to Pd(0) phosphine complexes bearing triphenylphosphine and bischelating 1,2-bis(diphenylphosphino)ethane (dppe). The structures of Pd-PDI complexes were elucidated by single-crystal X-ray analysis. Surprisingly, despite direct attachement of two late transition metal centers, Pd-PDI systems are highly fluorescent (Phi=0.65 and 0.22 for triphenylphosphine and dppe systems, respectively). This is rationalized in terms of weak electronic interactions between the metal centers and PDI pi-system, as revealed by TD-DFT calculations.
Weissman
Haim
H
Department of Organic Chemistry and Chemical Research Support Unit, Weizmann Institute of Science, Rehovot 76100, Israel.
Shirman
Elijah
E
Ben-Moshe
Tal
T
Cohen
Revital
R
Leitus
Gregory
G
Shimon
Linda J W
LJ
Rybtchinski
Boris
B