Electron transfer in self-assembled orthogonal structures.
Two new molecular dyads, comprising pyrromethene (bodipy) and 2,2':6',2"-terpyridine (terpy) subunits, have been synthesized and fully characterized. Absorption and fluorescence spectral profiles are dominated by contributions from the bodipy unit. Zinc(II) cations bind to the vacant terpy ligand to form both 1:1 and 1:2 (cation:ligand) complexes, as evidenced by X-ray structural data, NMR and spectrophotometric titrations. Attachment of the cations is accompanied by a substantial decrease in fluorescence from the bodipy chromophore due to intramolecular electron transfer across the orthogonal structure. At low temperature, nuclear tunneling occurs and the rate of electron transfer is essentially activationless. However, activated electron transfer is seen at higher temperatures and allows calculation of the corresponding reorganization energy and electronic coupling matrix element. In both cases, charge recombination is faster than charge separation.
Harriman
Anthony
A
Molecular Photonics Laboratory, School of Natural Sciences, Bedson Building, University of Newcastle, Newcastle upon Tyne NE1 7RU, United Kingdom. anthony.harriman@ncl.ac.uk
Rostron
James P
JP
Cesario
Michèle
M
Ulrich
Gilles
G
Ziessel
Raymond
R
D001896:Boron Compounds / Q000138:chemical synthesis / Q000737:chemistry; D002614:Chelating Agents / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D004579:Electron Transport; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D011725:Pyridines / Q000138:chemical synthesis / Q000737:chemistry; D013053:Spectrophotometry; D015032:Zinc / Q000737:chemistry*
C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D002614:Chelating Agents; D005456:Fluorescent Dyes; D011725:Pyridines; D015032:Zinc