Light-Induced Charge Separation in Densely Packed Donor-Acceptor Coordination Cages.
Photon-powered charge separation is achieved in a supramolecular architecture based on the dense packing of functional building blocks. Therefore, self-assembled dimers of interpenetrated coordination cages consisting of redoxactive chromophors were synthesized in a single assembly step starting from easily accessible ligands and Pd(II) cations. Two backbones consisting of electron rich phenothiazine (PTZ) and electron deficient anthraquinone (ANQ) were used to assemble either homo-octameric or mixed-ligand double cages. The electrochemical and spectroscopic properties of the pure cages, mixtures of donor and acceptor cages and the mixed-ligand cages were compared by steady-state UV-vis and transient absorption spectroscopy, supported by cyclic voltammetry and spectroelectrochemistry. Only the mixed-ligand cages, allowing close intra-assembly communication between the donors and acceptors, showed the evolution of characteristic PTZ radical cation and ANQ radical anion features upon excitation in the transient spectra. In contrast, excitation of the mixtures of the homo-octameric donor and acceptor cages in solution did not lead to any signs of electron transfer. Densely packed photo- and redox-functional self-assemblies promise molecular-level control over the morphology of the charge separation layer in future photovoltaic applications.
Institute for Inorganic Chemistry, Georg-August University Göttingen , Tammannstraße 4, 37077 Göttingen, Germany.
Marina
M
Frank
Max-Planck-Institute for Biophysical Chemistry , Am Fassberg 11, 37077 Göttingen, Germany.
Jennifer
J
Ahrens
Institute for Inorganic Chemistry, Georg-August University Göttingen , Tammannstraße 4, 37077 Göttingen, Germany.
Isabel
I
Bejenke
Institute for Inorganic Chemistry, Georg-August University Göttingen , Tammannstraße 4, 37077 Göttingen, Germany.
Marcel
M
Krick
Max-Planck-Institute for Biophysical Chemistry , Am Fassberg 11, 37077 Göttingen, Germany.
Dirk
D
Schwarzer
Institute for Inorganic Chemistry, Georg-August University Göttingen , Tammannstraße 4, 37077 Göttingen, Germany.|Faculty of Chemistry and Chemical Biology, TU Dortmund University , Otto-Hahn-Straße 6, 44227 Dortmund, Germany.
Guido H
GH
Clever