title: Fused perylene-phthalocyanine macrocycles: a new family of NIR-dyes with pronounced basicity.
abstract: The synthesis and characterization of a new type of chromophore, namely PePc consisting of a central phthalocyanine core and four fused perylene-bisimide (PBI) units is described for the first time. The entire architecture represents a highly extended conjugated heterocyclic π-system with C4h symmetry. In order to guarantee pronounced solubility in organic solvents the corresponding PBI units were bay-functionalized with tert-butylphenoxy substituents. Next to the metal-free macrocycle, PePcH2 , also metallated macrocycles PePcM (M=Zn, Ni, Pb, Ru, Fe) were synthesized. The extensive fusion of the corresponding aromatic building blocks to the very large extended π-system leads to a very narrow HOMO-LUMO gap and as a consequence to transparency in the visible but light absorption in the NIR region. Significantly, the azomethine N-atoms N1N4 of PePcM and PePcH2 are highly basic. The corresponding tetraprotonated systems can only be deprotonated with very strong non-nucleophilic bases such as phosphazene bases. In the protonated forms PePcMH4 (4+) and PePcMH6 (4+) the absorption maximum is shifted back to the visible region due to the loss of conjugation. The experimental findings were corroborated with quantum mechanical calculations.
authors.affiliation: Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Organische Chemie II, Henkestrasse 42, 91054 Erlangen (Germany).
authors.forename: Jörg
authors.initials: J
authors.lastname: Schönamsgruber
authors.forename: Harald
authors.initials: H
authors.lastname: Maid
authors.forename: Walter
authors.initials: W
authors.lastname: Bauer
authors.forename: Andreas
authors.initials: A
authors.lastname: Hirsch
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D007094:Imides / Q000737:chemistry*; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry*; D054833:Isoindoles; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D004396:Coloring Agents; D007094:Imides; D007211:Indoles; D054833:Isoindoles; D008670:Metals; C510697:perylene bisimide; D010569:Perylene; C013647:phthalocyanine
keywords: macrocycles; new near infrared dyes; perylene; phthalocyanines; rylene