Premium
Systematic Investigation of Photoinduced Electron Transfer Controlled by Internal Charge Transfer and Its Consequences for Selective PdCl 2 Coordination
Author(s) -
Schwarze Thomas,
Mickler Wulfhard,
Dosche Carsten,
Flehr Roman,
Klamroth Tillmann,
Löhmannsröben HansGerd,
Saalfrank Peter,
Holdt HansJürgen
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200902281
Subject(s) - anthracene , fluorescence , moiety , chemistry , fluorophore , photoinduced electron transfer , pyrene , electron transfer , photochemistry , alkyl , stereochemistry , organic chemistry , physics , quantum mechanics
Fluoroionophores of fluorophore–spacer–receptor format were prepared for detection of PdCl 2 by fluorescence enhancement. The fluorescent probes 1 – 13 consist of a fluorophore group, an alkyl spacer and a dithiomaleonitrile PdCl 2 receptor. First, varying the length of the alkylene spacer (compounds 1 – 3 ) revealed a dominant through‐space pathway for oxidative photoinduced electron transfer (PET) in CH 2 ‐bridged dithiomaleonitrile fluoroionophores. Second, fluorescent probes 4 – 9 containing two anthracene or pyrene fragments connected through CH 2 bridges to the dithiomaleonitrile unit were synthesized. Modulation of the oxidation potential ( E Ox ) through electron‐withdrawing or ‐donating groups on the anthracene moiety regulates the thermodynamic driving force for oxidative PET (Δ G PET ) in bis(anthrylmethylthio)maleonitriles and therefore the fluorescence quantum yields ( Φ f ), too. The new concept was confirmed and transferred to pyrenyl ligands, and fluorescence enhancements (FE) greater than 3.2 in the presence of PdCl 2 were achieved by 7 and 8 (FE=5.4 and 5.2). Finally, for comparison, monofluorophore ligands 10 – 13 were synthesized.