title: Palladium complexes of perylene diimides: strong fluorescence despite direct attachment of late transition metals to organic dyes.
abstract: 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.
authors.affiliation: Department of Organic Chemistry and Chemical Research Support Unit, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Haim
authors.initials: H
authors.lastname: Weissman
authors.forename: Elijah
authors.initials: E
authors.lastname: Shirman
authors.forename: Tal
authors.initials: T
authors.lastname: Ben-Moshe
authors.forename: Revital
authors.initials: R
authors.lastname: Cohen
authors.forename: Gregory
authors.initials: G
authors.lastname: Leitus
authors.forename: Linda J W
authors.initials: LJ
authors.lastname: Shimon
authors.forename: Boris
authors.initials: B
authors.lastname: Rybtchinski