title: Programmed metalloporphyrins for self-assembly within light-harvesting stacks: (5,15-dicyano-10,20-bis(3,5-di-tert-butylphenyl)porphyrinato)zinc(II) and its push-pull 15-N,N-dialkylamino-5-cyano congeners obtained by a facile direct amination.
abstract: The title dicyano compound was synthesized via cyanation and it self-assembles in nonpolar solvents giving red-shifted and broad absorption maxima just as the bacteriochlorophylls which are encountered in the light-harvesting organelles of early photosynthetic bacteria. In the crystal, stacks are formed through a hierarchic combination of pi-stacking and a CN-Zn electrostatic interaction. Push-pull 15-N,N-dialkylamino-5-cyano congeners could be obtained in high yields using a solvent- and catalyst-free direct amination of meso-bromoporphyrins. Importantly, the fluorescence of the self-assembled species due to the very orderly manner in which the chromophores are arranged is not entirely quenched and has a surprisingly long lifetime of over 1 ns. This lends hope of using the trapped energy in biomimetic hybrid solar cells.
authors.affiliation: Karlsruhe Institute of Technology, Forschungszentrum Karlsruhe, Institute for Nanotechnology, Postfach 3640, D-76021 Karlsruhe, Germany.
authors.forename: Mihaela Carmen
authors.initials: MC
authors.lastname: Balaban
authors.forename: Andreas
authors.initials: A
authors.lastname: Eichhöfer
authors.forename: Gernot
authors.initials: G
authors.lastname: Buth
authors.forename: Robert
authors.initials: R
authors.lastname: Hauschild
authors.forename: Jedrzej
authors.initials: J
authors.lastname: Szmytkowski
authors.forename: Heinz
authors.initials: H
authors.lastname: Kalt
authors.forename: Teodor Silviu
authors.initials: TS
authors.lastname: Balaban
mesh_terms: D000586:Amination; D003460:Crystallization; D018360:Crystallography, X-Ray; D008027:Light; D008665:Metalloporphyrins / Q000737:chemistry*; D008954:Models, Biological; D015394:Molecular Structure; D015388:Organelles / Q000737:chemistry; D010777:Photochemistry; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
chemical_list: C530027:(5,15-dicyano-10,20-bis(3,5-di-tert-butylphenyl)porphyrinato)zinc(II); D008665:Metalloporphyrins