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 - Müller, Holger A1 - Kelling, Alexandra A1 - Schilde, Uwe A1 - Holdt, Hans-Jürgen T1 - Ag(I)-, Hg(II)- und Pt(II)-Komplexe von Maleonitril-thiakronenethern BT - Silber(II)-, Quecksilber(II)- und Platin(II)-Komplexe von Maleonitril-thiakronenethern N2 - The synthesis and single crystal X-ray structures of eight AgI, HgII, and PtII complexes with the thiacrown ethers maleonitrile-tetrathia-12-crown-4 (mn12S4), maleonitrile-tetrathia-13-crown-4 (mn13S4), and maleonitrile- pentathia-15-crown-5 (mn15S5) (1) are reported. The ligand mn15S5 was synthesized for the first time and characterized by X-ray diffraction. With silver(I) perchlorate and silver(I) tetrafluoroborate it forms the chiral complexes [Ag(mn15S5)]ClO4·CH3NO2 (2) and [Ag(mn15S5)]BF4·CH3NO2·0.25H2O (3) with half-sandwich moieties. AgI is located in a distorted tetrahedral coordination environment, involving three sulfur atoms of the crown cycle and a fourth one of the adjacent half-sandwich moiety, forming a helical structure. The reaction of Hg(ClO4)2 with mn13S4 yielded the dinuclear complex [Hg2(mn13S4)3](ClO4)4 (4) containing two half-sandwich moieties with a third ligand molecule as a bridging unit. Mercury(II) chloride and mercury(II) iodide react with mn12S4 and mn13S4 to form complexes of the general composition [HgX2(L)] (X = Cl, I; L = mn12S4, mn13S4): [HgCl2(mn12S4)] (5), [HgI2(mn12S4)] (6), [HgCl2(mn13S4)] (7) or [HgX2(L)2] (X = I; L = mn13S4): [HgI2(mn13S4)2] (8). Only one or two sulfur atoms of the ligand are involved in the complexation, and chain or ribbon structures are formed. In these compounds the HgX2 units (X = Cl, I) are preserved, coordinated by sulfur atoms of bridging mn12S4 or mn13S4 ligands. In all complexes of this type, the metal atoms are not coordinated inside the cavity, but in an exocyclic mode, because the diameter of the macrocycle is too small. Additionally, the PtCl2 complex of mn12S4 was investigated, where PtII is coordinated in an exocyclic mode forming the complex [PtCl2(mn12S4)] (9). Two of the four sulfur atoms of the macrocycle are bonded to the metal giving together with both chlorine atoms a square-planar coordination geometry. Together with a long-range interaction with a further sulfur atom of the macrocycle a square-pyramidal coordination environment is formed. Y1 - 2009 UR - http://www.znaturforsch.com/rb/s64b1003.pdf SN - 0932-0776 ER - TY - JOUR A1 - Träger, Juliane A1 - Klamroth, Tillmann A1 - Kelling, Alexandra A1 - Lubahn, Susanne A1 - Cleve, Ernst A1 - Mickler, Wulfhard A1 - Heydenreich, Matthias A1 - Müller, Holger A1 - Holdt, Hans-Jürgen T1 - Complexation of Palladium(II) with unsaturated Dithioethers a systematic development of highly selective ligands for solvent extraction JF - European journal of inorganic chemistry : a journal of ChemPubSoc Europe N2 - There is a demand for new and robust PdII extractants due to growing recycling rates. Chelating dithioethers are promising substances for solvent extraction as they form stable square-planar complexes with PdII. We have modified unsaturated dithioethers, which are known to coordinate PdII, and adapted them to the requirements of industrial practice. The ligands are analogues of 1,2-dithioethene with varying electron-withdrawing backbones and polar end-groups. The crystal structures of several ligands and their palladium complexes were determined as well as their electro- and photochemical properties, complex stability and behaviour in solution. Solvent extraction experiments showed the superiority of some of our ligands over conventionally used extractants in terms of their very fast reaction rates. With highly selective 1,2-bis(2-methoxyethylthio)benzene (4) it is possible to extract PdII from a highly acidic medium in the presence of other base and palladium-group metals. KW - Renewable resources KW - Palladium KW - Chelates KW - Ligand design KW - S li-gands Y1 - 2012 U6 - https://doi.org/10.1002/ejic.201101406 SN - 1434-1948 IS - 14 SP - 2341 EP - 2352 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Starke, Ines A1 - Fürstenberg, Sylvia A1 - Müller, Holger A1 - Holdt, Hans-Jürgen A1 - Kleinpeter, Erich T1 - Electrospray mass spectrometric studies of the complexational behavior of maleonitrile thiacrown ethers with various metals N2 - Electrospray ionization was employed to study the mass spectrometric behavior of the maleonitrile tetrathiacrown ethers mn12S(4) (1) and mn13S(4) (2) and maleonitrile pentathiacrown ether mn15S(5) (3) and of their complexes with various metal salts (MX2, M=Pd, Pt, Ni, Co, Fe; X=Cl, CrCl3, Ni(BF4)(2), TIPF6 or Cd(NO3)(2)) and Cu(SO3CF3)(2). Both singly charged, [MXL](+) and [MXL2]+, and doubly charged complexes, [MLn](2+) (n = 2-5), were observed. The formation of the different complexes consisting of the transition metal ion, the counterion and the various crown ethers and their subsequent dissociation was also studied by collision-induced dissociation measurements which were also used to evaluate the relative stabilities of the complexes. It was found that the collisional voltages for the dissociation of the complexes were generally greater in the [MXL](+) complexes than in the corresponding [MXL2]+ complexes. Copyright (c) 2006 John Wiley & Sons, Ltd Y1 - 2006 UR - http://onlinelibrary.wiley.com/doi/10.1002/rcm.2384/full U6 - https://doi.org/10.1002/Rcm.2384 ER - TY - JOUR A1 - Schwarze, Thomas A1 - Müller, Holger A1 - Ast, Sandra A1 - Steinbrück, Dörte A1 - Eidner, Sascha A1 - Geißler, Felix A1 - Kumke, Michael Uwe A1 - Holdt, Hans-Jürgen ED - Kumke, Michael Uwe T1 - Fluorescence lifetime-based sensing of sodium by an optode JF - Chemical Communications N2 - We report a 1,2,3-triazol fluoroionophore for detecting Na+ that shows in vitro enhancement in the Na+-induced fluorescence intensity and decay time. The Na+-selective molecule 1 was incorporated into a hydrogel as a part of a fiber optical sensor. This sensor allows the direct determination of Na+ in the range of 1–10 mM by measuring reversible fluorescence decay time changes. KW - ion optodes KW - sensors KW - indicators KW - chromoionophore KW - ionophore KW - membrane KW - switches KW - systems KW - samples KW - green Y1 - 2014 SN - 0022-4936 SN - 0009-241X SP - 14167 EP - 14170 PB - The Royal Society Chemistry CY - Cambridge ER - TY - GEN A1 - Schwarze, Thomas A1 - Müller, Holger A1 - Ast, Sandra A1 - Steinbrück, Dörte A1 - Eidner, Sascha A1 - Geißler, Felix A1 - Kumke, Michael Uwe A1 - Holdt, Hans-Jürgen T1 - Fluorescence lifetime-based sensing of sodium by an optode N2 - We report a 1,2,3-triazol fluoroionophore for detecting Na+ that shows in vitro enhancement in the Na+-induced fluorescence intensity and decay time. The Na+-selective molecule 1 was incorporated into a hydrogel as a part of a fiber optical sensor. This sensor allows the direct determination of Na+ in the range of 1–10 mM by measuring reversible fluorescence decay time changes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 182 KW - ion optodes KW - sensors KW - indicators KW - chromoionophore KW - ionophore KW - membrane KW - switches KW - systems KW - samples KW - green Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-76785 SP - 14167 EP - 14170 PB - The Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Ast, Sandra A1 - Müller, Holger A1 - Flehr, Roman A1 - Klamroth, Tillmann A1 - Walz, Bernd A1 - Holdt, Hans-Jürgen T1 - High Na+ and K+-induced fluorescence enhancement of a pi-conjugated phenylaza-18-crown-6-triazol-substituted coumarin fluoroionophore JF - Chemical communications N2 - The new pi-conjugated 1,2,3-triazol-1,4-diyl fluoroionophore 1 generated via Cu(I) catalyzed [3 + 2] cycloaddition shows high fluorescence enhancement factors (FEF) in the presence of Na+ (FEF = 58) and K+ (FEF = 27) in MeCN and high selectivity towards K+ under simulated physiological conditions (160 mM K+ or Na+, respectively) with a FEF of 2.5 for K+. Y1 - 2011 U6 - https://doi.org/10.1039/c0cc04370b SN - 1359-7345 VL - 47 IS - 16 SP - 4685 EP - 4687 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Alrefai, Anas A1 - Mondal, Suvendu Sekhar A1 - Wruck, Alexander A1 - Kelling, Alexandra A1 - Schilde, Uwe A1 - Brandt, Philipp A1 - Janiak, Christoph A1 - Schoenfeld, Sophie A1 - Weber, Birgit A1 - Rybakowski, Lawrence A1 - Herrman, Carmen A1 - Brennenstuhl, Katlen A1 - Eidner, Sascha A1 - Kumke, Michael Uwe A1 - Behrens, Karsten A1 - Günter, Christina A1 - Müller, Holger A1 - Holdt, Hans-Jürgen T1 - Hydrogen-bonded supramolecular metal-imidazolate frameworks: gas sorption, magnetic and UV/Vis spectroscopic properties JF - Journal of Inclusion Phenomena and Macrocyclic Chemistry N2 - By varying reaction parameters for the syntheses of the hydrogen-bonded metal-imidazolate frameworks (HIF) HIF-1 and HIF-2 (featuring 14 Zn and 14 Co atoms, respectively) to increase their yields and crystallinity, we found that HIF-1 is generated in two different frameworks, named as HIF-1a and HIF-1b. HIF-1b is isostructural to HIF-2. We determined the gas sorption and magnetic properties of HIF-2. In comparison to HIF-1a (Brunauer-Emmett-Teller (BET) surface area of 471m(2) g(-1)), HIF-2 possesses overall very low gas sorption uptake capacities [BET(CO2) surface area=85m(2) g(-1)]. Variable temperature magnetic susceptibility measurement of HIF-2 showed antiferromagnetic exchange interactions between the cobalt(II) high-spin centres at lower temperature. Theoretical analysis by density functional theory confirmed this finding. The UV/Vis-reflection spectra of HIF-1 (mixture of HIF-1a and b), HIF-2 and HIF-3 (with 14 Cd atoms) were measured and showed a characteristic absorption band centered at 340nm, which was indicative for differences in the imidazolate framework. KW - Gas-sorption KW - Ligand design KW - Magnetic properties KW - Supramolecular chemistry KW - Solvothermal synthesis Y1 - 2019 U6 - https://doi.org/10.1007/s10847-019-00926-6 SN - 1388-3127 SN - 1573-1111 VL - 94 IS - 3-4 SP - 155 EP - 165 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Debatin, Franziska A1 - Thomas, Arne A1 - Kelling, Alexandra A1 - Hedin, Niklas A1 - Bacsik, Zoltan A1 - Senkovska, Irena A1 - Kaskel, Stefan A1 - Junginger, Matthias A1 - Müller, Holger A1 - Schilde, Uwe A1 - Jäger, Christian A1 - Friedrich, Alwin A1 - Holdt, Hans-Jürgen T1 - In situ synthesis of an imidazolate-4-amide-5-imidate ligand and formation of a microporous zinc-organic framework with H2-and CO2-storage ability N2 - Narrow channels with polar walls are the structural and functional features responsible for the high capacity of a zinc-organic framework based on an imidazolate-amide-imidate ligand for the uptake of H2 and CO2 (see structure: orange Zn, blue N, red O, dark gray C, light gray H). The rigid and stable chelating ligand was synthesized in situ by partial hydrolysis of a dicyanoimidazole compound. Y1 - 2010 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/26737/ U6 - https://doi.org/10.1002/anie.200906188 SN - 1433-7851 ER - TY - JOUR A1 - Ast, Sandra A1 - Fischer, Tobias A1 - Müller, Holger A1 - Mickler, Wulfhard A1 - Schwichtenberg, Mathias A1 - Rurack, Knut A1 - Holdt, Hans-Jürgen T1 - Integration of the 1,2,3-Triazole "Click" Motif as a potent signalling element in metal ion responsive fluorescent probes JF - Chemistry - a European journal N2 - In a systematic approach we synthesized a new series of fluorescent probes incorporating donoracceptor (D-A) substituted 1,2,3-triazoles as conjugative -linkers between the alkali metal ion receptor N-phenylaza-[18]crown-6 and different fluorophoric groups with different electron-acceptor properties (4-naphthalimide, meso-phenyl-BODIPY and 9-anthracene) and investigated their performance in organic and aqueous environments (physiological conditions). In the charge-transfer (CT) type probes 1, 2 and 7, the fluorescence is almost completely quenched by intramolecular CT (ICT) processes involving charge-separated states. In the presence of Na+ and K+ ICT is interrupted, which resulted in a lighting-up of the fluorescence in acetonitrile. Among the investigated fluoroionophores, compound 7, which contains a 9-anthracenyl moiety as the electron-accepting fluorophore, is the only probe which retains light-up features in water and works as a highly K+/Na+-selective probe under simulated physiological conditions. Virtually decoupled BODIPY-based 6 and photoinduced electron transfer (PET) type probes 35, where the 10-substituted anthracen-9-yl fluorophores are connected to the 1,2,3-triazole through a methylene spacer, show strong ion-induced fluorescence enhancement in acetonitrile, but not under physiological conditions. Electrochemical studies and theoretical calculations were used to assess and support the underlying mechanisms for the new ICT and PET 1,2,3-triazole fluoroionophores. KW - charge transfer KW - click chemistry KW - electron transfer KW - fluorescent probes KW - metal ions Y1 - 2013 U6 - https://doi.org/10.1002/chem.201201575 SN - 0947-6539 VL - 19 IS - 9 SP - 2990 EP - 3005 PB - Wiley-VCH CY - Weinheim ER -