TY  - JOUR
A1  - Ast, Sandra
A1  - Schwarze, Thomas
A1  - Müller, Holger
A1  - Sukhanov, Aleksey
A1  - Michaelis, Stefanie
A1  - Wegener, Joachim
A1  - Wolfbeis, Otto S.
A1  - Körzdörfer, Thomas
A1  - Dürkop, Axel
A1  - Holdt, Hans-Jürgen
T1  - A highly K+-Selective Phenylaza-[18]crown-6-Lariat-Ether-Based Fluoroionophore and its application in the sensing of K+ Ions with an optical sensor film and in cells
JF  - Chemistry - a European journal
N2  - Herein, we report the synthesis of two phenylaza-[18]crown-6 lariat ethers with a coumarin fluorophore (1 and 2) and we reveal that compound 1 is an excellent probe for K+ ions under simulated physiological conditions. The presence of a 2-methoxyethoxy lariat group at the ortho position of the anilino moiety is crucial to the substantially increased stability of compounds 1 and 2 over their lariat-free phenylaza-[18] crown-6 ether analogues. Probe 1 shows a high K+/Na+ selectivity and a 2.5-fold fluorescence enhancement was observed in the presence of 100 mm K+ ions. A fluorescent membrane sensor, which was prepared by incorporating probe 1 into a hydrogel, showed a fully reversible response, a response time of 150 s, and a signal change of 7.8% per 1 mm K+ within the range 1-10 mm K+. The membrane was easily fabricated (only a single sensing layer on a solid polyester support), yet no leaching was observed. Moreover, compound 1 rapidly permeated into cells, was cytocompatible, and was suitable for the fluorescent imaging of K+ ions on both the extracellular and intracellular levels.
KW  - crown compounds
KW  - fluorescence
KW  - gels
KW  - potassium
KW  - sensors
Y1  - 2013
U6  - https://doi.org/10.1002/chem.201302350
SN  - 0947-6539
SN  - 1521-3765
VL  - 19
IS  - 44
SP  - 14911
EP  - 14917
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Schwarze, Thomas
A1  - Traeger, Juliane
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Holdt, Hans-Jürgen
T1  - Macrocyclic dithiomaleonitriles for an efficient PdCl2 coordination
JF  - Inorganica chimica acta : the international inorganic chemistry journal
N2  - We have synthesized a set of new unsaturated macrocyclic dithioethers with an increasing number of flexible methylene units 1-7 (Scheme 2) to investigate the correlation between the ring size of these ligands, the chelation effect and the consequences for an efficient PdCl2 coordination. The dithioethers 1-7 and the complex [PdCl2(4)]center dot CHCl3 were characterized by X-ray diffraction analysis. The crystal structures of 1-7 show that 2-7 are better preorganized chelating ligands for an exocyclic PdCl2 coordination than 1. The chelation effect of 1-7, the orientation of the sulfur atoms and the S center dot center dot center dot S donor distances, are influenced by the flexibility of the methylene units. In this series the unsaturated macrocyclic ligands 5 and 6 are the best chelating ligands for an efficient PdCl2 coordination. Comparative solvent extraction experiments with mn-12S(2)O(2) (mn = maleonitrile) reveal that the low interface activity of the new ligands reduces the extraction rate. However, a comparison with open-chain dithiomaleonitriles shows the impact of the macrocyclic effect of 4 and 5 on the extraction yield.
KW  - Thioether ligands
KW  - Palladium
KW  - Synthesis
KW  - X-ray diffraction
KW  - Chelation effect
KW  - Extraction
Y1  - 2013
U6  - https://doi.org/10.1016/j.ica.2013.08.020
SN  - 0020-1693
SN  - 1873-3255
VL  - 408
IS  - 2
SP  - 53
EP  - 58
PB  - Elsevier
CY  - Lausanne
ER  -