TY  - JOUR
A1  - Schwarze, Thomas
A1  - Dosche, Carsten
A1  - Flehr, Roman
A1  - Klamroth, Tillmann
A1  - Löhmannsröben, Hans-Gerd
A1  - Saalfrank, Peter
A1  - Cleve, Ernst
A1  - Buschmann, Hans-Jürgen
A1  - Holdt, Hans-Jürgen
T1  - Combination of a CT modulated PET and an intramolecular excimer formation to quantify PdCl2 by large fluorescence enhancement
N2  - The [6.6](9,10)anthracenophane 1 (Scheme 1) is a selective fluoroionophore for the detection of PdCl2 with a large fluorescence enhancement factor (I/I-0 > 250).
Y1  - 2010
UR  - http://pubs.rsc.org/en/content/articlehtml/2010/cc/b919973j
U6  - https://doi.org/10.1039/B919973j
SN  - 1359-7345
ER  - 
TY  - JOUR
A1  - Schwarze, Thomas
A1  - Dosche, Carsten
A1  - Flehr, Roman
A1  - Klamroth, Tillmann
A1  - Löhmannsröben, Hans-Gerd
A1  - Saalfrank, Peter
A1  - Cleve, Ernst
A1  - Buschmann, Hans-Jürgen
A1  - Holdt, Hans-Jürgen
T1  - Combination of a CT modulated PET and an intramolecular excimer formation to quantify PdCl2 by large fluorescence enhancement
Y1  - 2010
UR  - http://www.rsc.org/ej/CC/2010/b919973j.pdf
SN  - 1359-7345
ER  - 
TY  - GEN
A1  - Schwarze, Thomas
A1  - Riemer, Janine
A1  - Müller, Holger
A1  - John, Leonard
A1  - Holdt, Hans‐Jürgen
A1  - Wessig, Pablo
T1  - Na+ Selective Fluorescent Tools Based on Fluorescence Intensity Enhancements, Lifetime Changes, and on a Ratiometric Response
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Over the years, we developed highly selective fluorescent probes for K+ in water, which show K+-induced fluorescence intensity enhancements, lifetime changes, or a ratiometric behavior at two emission wavelengths (cf. Scheme 1, K1-K4). In this paper, we introduce selective fluorescent probes for Na+ in water, which also show Na+ induced signal changes, which are analyzed by diverse fluorescence techniques. Initially, we synthesized the fluorescent probes 2, 4, 5, 6 and 10 for a fluorescence analysis by intensity enhancements at one wavelength by varying the Na+ responsive ionophore unit and the fluorophore moiety to adjust different K-d values for an intra- or extracellular Na+ analysis. Thus, we found that 2, 4 and 5 are Na+ selective fluorescent tools, which are able to measure physiologically important Na+ levels at wavelengths higher than 500 nm. Secondly, we developed the fluorescent probes 7 and 8 to analyze precise Na+ levels by fluorescence lifetime changes. Herein, only 8 (K-d=106 mm) is a capable fluorescent tool to measure Na+ levels in blood samples by lifetime changes. Finally, the fluorescent probe 9 was designed to show a Na+ induced ratiometric fluorescence behavior at two emission wavelengths. As desired, 9 (K-d=78 mm) showed a ratiometric fluorescence response towards Na+ ions and is a suitable tool to measure physiologically relevant Na+ levels by the intensity change of two emission wavelengths at 404 nm and 492 nm.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1136 
KW  - crown compounds
KW  - fluorescence lifetime
KW  - fluorescent probes
KW  - ratiometric
KW  - sodium
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-437482
SN  - 1866-8372
IS  - 1136
ER  - 
TY  - JOUR
A1  - Schwarze, Thomas
A1  - Mueller, Holger
A1  - Schmidt, Darya
A1  - Riemer, Janine
A1  - Holdt, Hans-Jürgen
T1  - Design of Na+-Selective Fluorescent Probes: A Systematic Study of the Na+-Complex Stability and the Na+/K+ Selectivity in Acetonitrile and Water
JF  - Chemistry - a European journal
N2  - There is a tremendous demand for highly Na+-selective fluoroionophores to monitor the top analyte Na+ in life science. Here, we report a systematic route to develop highly Na+/K+ selective fluorescent probes. Thus, we synthesized a set of fluoroionophores 1, 3, 4, 5, 8 and 9 (see Scheme 1) to investigate the Na+/K+ selectivity and Na(+-)complex stability in CH3CN and H2O. These Na+-probes bear different 15-crown-5 moieties to bind Na+ stronger than K+. In the set of the diethylaminocoumarin-substituted fluoroionophores 1-5, the following trend of fluorescence quenching 1 > 3 > 2 > 4 > 5 in CH3CN was observed. Therefore, the flexibility of the aza-15-crown-5 moieties in 1-4 determines the conjugation of the nitrogen lone pair with the aromatic ring. As a consequence, 1 showed in CH3CN the highest Na+-induced fluorescence enhancement (FE) by a factor of 46.5 and a weaker K+ induced FE of 3.7. The Na+-complex stability of 1-4 in CH3CN is enhanced in the following order of 2 > 4 > 3 > 1, assuming that the O-atom of the methoxy group in the ortho-position, as shown in 2, strengthened the Na+-complex formation. Furthermore, we found for the N( o-methoxyphenyl) aza-15-crown-5 substituted fluoroionophores 2, 8 and 9 in H2O, an enhanced Na+-complex stability in the following order 8 > 2 > 9 and an increased Na+/K+ selectivity in the reverse order 9 > 2 > 8. Notably, the Na+-induced FE of 8 (FEF = 10.9), 2 (FEF = 5.0) and 9 (FEF = 2.0) showed a similar trend associated with a decreased K+-induced FE [8 (FEF = 2.7) > 2 (FEF = 1.5) > 9 (FEF = 1.1)]. Here, the Na+-complex stability and Na+/K+ selectivity is also influenced by the fluorophore moiety. Thus, fluorescent probe 8 (K-d = 48 mm) allows high-contrast, sensitive, and selective Na+ measurements over extracellular K+ levels. A higher Na+/K+ selectivity showed fluorescent probe 9, but also a higher Kd value of 223 mm. Therefore, 9 is a suitable tool to measure Na+ concentrations up to 300 mm at a fluorescence emission of 614 nm.
KW  - crown compounds
KW  - fluorescence
KW  - fluorescent probes
KW  - potassium
KW  - sodium
Y1  - 2017
U6  - https://doi.org/10.1002/chem.201605986
SN  - 0947-6539
SN  - 1521-3765
VL  - 23
SP  - 7255
EP  - 7263
PB  - Wiley-VCH
CY  - Weinheim
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  - JOUR
A1  - Brietzke, Thomas Martin
A1  - Mickler, Wulfhard
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Krüger, Hans-Joerg
A1  - Holdt, Hans-Jürgen
T1  - Mono- and dinuclear Ruthenium(II)-1,6,7,12-Tetraazaperylene complexes of N,N '-Dimethyl-2,11-diaza[3.3](2,6)-pyridinophane
JF  - European journal of inorganic chemistry : a journal of ChemPubSoc Europe
N2  - Ruthenium(II) complexes [Ru(L-N4Me2)(dape)](PF6)2 {[1](PF6)2}, [Ru(L-N4Me2)(tape)](PF6)2 {[2](PF6)2}, and [{Ru(L-N4Me2)}2(mu-tape)](PF6)4 {[3](PF6)4} were synthesized in two reaction steps by first reacting [Ru(DMSO)4Cl2] with tetraazamacrocyclic ligand N,N'-dimethyl-2,11-diaza[3.3](2,6)-pyridinophane (L-N4Me2) in ethanol under microwave irradiation to the intermediate [Ru(L-N4Me2)Cl2], which was subsequently, without further isolation, reacted with 1,12-diazaperylene (dape) or 1,6,7,12-tetraazaperylene (tape). X-ray structures of [Ru(L-N4Me2)(dape)](PF6)2, [Ru(L-N4Me2)(tape)](PF6)2.acetone, and [{Ru(L-N4Me2)}2(mu-tape)](ClO4)4.MeCN were determined. The UV/Vis absorption spectra of [1](PF6)2, [2](PF6)2, and [3](PF6)4 in acetonitrile display intense low-energy dp(Ru)?p* (dape or tape) MLCT absorption bands centered at 579, 637, and 794 nm, respectively. Reversible metal oxidations for the bimetallic complex [{Ru(L-N4Me2)}2(mu-tape)]4+ ([3]4+) are detected at 1.69 and 1.28 V vs. SCE. The potential difference ?E = 410 mV and the intervalence-charge-transfer (IVCT) transition at 2472 nm indicate a high degree of electronic interaction between the two ruthenium ions mediated through the tape bridging ligand. All three complexes, [1]2+, [2]2+, and [3]4+, were characterized by UV/Vis spectroelectrochemistry. The monooxidized and monoreduced states, [1]3+, [2]3+, [3]5+, and [1]+, [2]+, [3]3+, are accessible by reversible one-electron oxidation and one-electron reduction processes, respectively, as documented by the observation of several stable isosbestic points in the spectral progressions. The second reduction in each complex and the second oxidation in [3]4+ prove to be irreversible in these spectroelectrochemical experiments. Monoreduced species [1]+, [2]+, and [3]3+ yield EPR signals indicating that the unpaired electron is mainly centered on the large surface ligands dape or tape.
KW  - Ruthenium
KW  - Macrocyclic li-gands
KW  - N ligands
KW  - Redox chemistry
KW  - Mixed-valent compounds
Y1  - 2012
U6  - https://doi.org/10.1002/ejic.201200667
SN  - 1434-1948
IS  - 29
SP  - 4632
EP  - 4643
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Träger, Juliane
A1  - König, Jana
A1  - Städtke, Anja
A1  - Holdt, Hans-Jürgen
T1  - Development of a solvent extraction system with 1,2-bis(2-methoxyethylthio) benzene for the selective separation of palladium(II) from secondary raw materials
JF  - Hydrometallurgy : an international journal devoted to all aspects of the aqueous processing of metals
N2  - The chelating dithioether 1,2-bis(2-methoxyethylthio)benzene. a novel solvent extractant for Pd(II), is aimed to be utilised in the selective recovery of palladium from spent automotive catalysts. For that, the extraction system has been further customised, including the choice of an appropriate diluent (1,2-dichlorobenzene) as well as an effective stripping agent (0.5 M thiourea in 0.1 M HCl), which both have been selected from a number of potential agents. It is shown in batch experiments that the selectivity for Pd(II) is maintained when the organic phase (10(-2) M 1,2-bis(2-methoxyethylthio)benzene in 1,2-dichlorobenzene) is used several times to extract an oxidising leach solution. According to the McCabe-Thiele plot two theoretical stages are needed to extract more than 98% of the Pd(II) contained in that solution. The calculation of the thermodynamic quantities Delta H degrees. Delta S degrees and Delta G degrees reveals that the reaction is entropy driven - the temperature has only a slight influence on the extraction yield. It is demonstrated that the mono-oxidised extractant has a catalytic effect on the extraction kinetics when the aqueous phase contains highly concentrated hydrochloric acid. HPLC measurements prove the presence of small quantities of 1-(2-methoxyethylsulfinyl)-2-(2-methoxyethylthio) benzene in the organic phase.
KW  - Solvent extraction
KW  - Palladium
KW  - S ligands
KW  - Extraction system development
KW  - Stripping
Y1  - 2012
U6  - https://doi.org/10.1016/j.hydromet.2012.07.002
SN  - 0304-386X
SN  - 1879-1158
VL  - 127
IS  - 5
SP  - 30
EP  - 38
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Brietzke, Thomas Martin
A1  - Mickler, Wulfhard
A1  - Kelling, Alexandra
A1  - Holdt, Hans-Jürgen
T1  - Mono- and dinuclear ruthenium(II) 1,6,7,12-tetraazaperylene complexes
JF  - Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry
N2  - We report the synthesis of free 1,6,7,12-tetraazaperylene (tape). Tape was obtained from 1,1'-bis-2,7-naphthyridine by potassium promoted cyclization followed by oxidation with air. Mono-and dinuclear ruthenium(II) 1,6,7,12-tetraazaperylene complexes of the general formulas [Ru(L-L)(2)(tape)](PF6)(2), [1] (PF6)(2)-[5](PF6)(2), and [{Ru(L-L)(2)}(2)(mu-tape)](PF6)(4), [6](PF6)(4)-[10](PF6)(4), with{L-L = phen, bpy, dmbpy (4,4'-dimethyl-2,2'-bipyridine), dtbbpy (4,4'-ditertbutyl-2,2'-bipyridine) and tmbpy (4,4' 5,5'-tetramethyl-2,2'- bipyridine)}, respectively, were synthesized. The X-ray structures of tape center dot 2CHCl(3) and the mononuclear complexes [Ru(bpy)(2)(tape)](PF6)(2)center dot 0.5CH(3)CN center dot 0.5toluene, [Ru(dmbpy)(2)(tape)] (PF6)(2)center dot 2toluene and [Ru(dtbbpy)(2)(tape)](PF6)(2) center dot 3acetone center dot 0.5H(2)O were solved. The UV-vis absorption spectra and the electrochemical behavior of the ruthenium(II) tape complexes were explored and compared with the data of the analogous dibenzoeilatin (dbneil), 2,2'-bipyrimidine (bpym) and tetrapyrido [3,2-a:2',3'-c:3 '',2''-h:2''',3'''-j] phenazin (tpphz) species.
Y1  - 2012
U6  - https://doi.org/10.1039/c2dt11805j
SN  - 1477-9226
VL  - 41
IS  - 9
SP  - 2788
EP  - 2797
PB  - Royal Society of Chemistry
CY  - Cambridge
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  - Hahn, Simone
A1  - Holdt, Hans-Jürgen
T1  - Extraction of hexachloroplatinate from hydrochloric acid solutions with phosphorylated hexane-1,6-diyl polymers
JF  - Reactive & functional polymers
N2  - A series of diols (diethylene glycol, triethylene glycol, butane-1,4-diol and hexane-1,6-diol) were immobilized onto Merrifield resin and subsequently phosphorylated with dialkyl chlorophosphate (alkyl = Me, Et, Bu). The resins bearing hexane-1,6-diyl groups exhibited very good extraction abilities in regard to precious metal chloro complexes like platinum(IV), palladium(II) and rhodium(III). In batch experiments, more than 98% of Pt(IV) is extracted even when the metal and the hydrochloric acid concentration is enhanced significantly. Elution can be achieved with a solution of 0.5 mol L-1 thiourea in 0.1 mol L-1 hydrochloric acid. In the presence of other noble metals, platinum(IV) is preferentially bound. The extraction yield decreases in slightly acidic solution in the following order: Pt(IV)approximate to Pd(II)>Rh(III) and changes with increasing hydrochloric acid concentration to Pt(IV)>Pd(II)>> Rh(III). At different ratios of metal and acid, the temperature has nearly no influence on the platinum extraction. On slightly acidic media, the extraction of rhodium decreases by 30% when the temperature is increased from 10 degrees C to 40 degrees C. When the acid and metal concentration is enhanced, the palladium extraction decreases by 7-9%, depending on the resin.
KW  - Solid-phase extraction
KW  - Platinum group metals
KW  - Modified polymer resin
KW  - Phosphate
KW  - Adsorption isotherm
Y1  - 2012
U6  - https://doi.org/10.1016/j.reactfunctpolym.2012.08.004
SN  - 1381-5148
VL  - 72
IS  - 11
SP  - 878
EP  - 888
PB  - Elsevier
CY  - Amsterdam
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  - Schwarze, Thomas
A1  - Kelling, Alexandra
A1  - Müller, Holger
A1  - Trautmann, Michael
A1  - Klamroth, Tillmann
A1  - Baumann, Otto
A1  - Strauch, Peter
A1  - Holdt, Hans-Jürgen
T1  - N-2-Pyridinylmethyl-N '-arylmethyl-diaminomaleonitriles: New Highly Selective Chromogenic Chemodosimeters for Copper(II)
JF  - Chemistry - a European journal
KW  - amides
KW  - chemodosimeter
KW  - colorimetric detection
KW  - copper
KW  - sensors
KW  - UV
KW  - Vis spectroscopy
Y1  - 2012
U6  - https://doi.org/10.1002/chem.201201731
SN  - 0947-6539
VL  - 18
IS  - 34
SP  - 10506
EP  - 10510
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Kirste, Matthias
A1  - Brietzke, Thomas Martin
A1  - Holdt, Hans-Jürgen
A1  - Schilde, Uwe
T1  - The crystal structure of 1,12-diazaperylene, C₁₈H₁₀N₂
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - C₁₈H₁₀N₂, monoclinic, P2₁/c (no. 14), a=7.9297(9) Å,
b=11.4021(14) Å, c=13.3572(15) Å, β=105.363(8)°,
V =1164.5(2) ų, Z =4, Rgt(F)=0.0325, wRref(F²)=0.0774,
T =210(2) K.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 752 
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436501
SN  - 1866-8372
IS  - 752
ER  - 
TY  - GEN
A1  - Grunwald, Nicolas
A1  - Kelling, Alexandra
A1  - Holdt, Hans-Jürgen
A1  - Schilde, Uwe
T1  - The crystal structure of 1,1′-bisisoquinoline, C18H12N2
N2  - C18H12N2, tetragonal, I41/a (no. 88), a=13.8885(6) Å, c=13.6718(6) Å, V =2637.2(3) Å3, Z =8, Rgt(F)=0.0295, wRref(F2)=0.0854, T =210 K. CCDC no.: 631823
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 380 
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-401952
ER  - 
TY  - JOUR
A1  - Hahn, Simone
A1  - Träger, Juliane
A1  - Holdt, Hans-Jürgen
T1  - Solid-Phase extraction of Pt(IV) with Dialkyl-(hexane-1,6-diyl) phosphate modified merrifield resins from aqueous chloride media in column operations
JF  - Separation and purification technology
N2  - A series of three dialkyl phosphate resins with a Merrifield resin support was used to extract platinum from acidic media. In column operations total capacities of 85-130 mg/g were gained. The presence of palladium and rhodium results in the order: Pt(IV) > Pd(II) >> Rh(III). From a leach liquor gained from spent automotive catalysts metals forming anionic chloro complexes are co-extracted only to a small extent. However, in order to separate and enrich platinum a selective back-extraction can be done with a sodium thiocyanate solution. A second elution step with acidic thiourea leads to a mixed solution of palladium and rhodium.
KW  - platinum
KW  - column operation mode
KW  - phosphate
KW  - solid-phase extraction
Y1  - 2015
U6  - https://doi.org/10.1080/01496395.2014.968264
SN  - 0149-6395
SN  - 1520-5754
VL  - 50
IS  - 2
SP  - 191
EP  - 206
PB  - Taylor & Francis Group
CY  - Philadelphia
ER  - 
TY  - JOUR
A1  - Kirste, Matthias
A1  - Brietzke, Thomas Martin
A1  - Holdt, Hans-Jürgen
A1  - Schilde, Uwe
T1  - The crystal structure of 1,12-diazaperylene, C₁₈H₁₀N₂
JF  - Zeitschrift für Kristallographie - New Crystal Structures
N2  - C₁₈H₁₀N₂, monoclinic, P2₁/c (no. 14), a=7.9297(9) Å,
b=11.4021(14) Å, c=13.3572(15) Å, β=105.363(8)°,
V =1164.5(2) ų, Z =4, Rgt(F)=0.0325, wRref(F²)=0.0774,
T =210(2) K.
Y1  - 2019
U6  - https://doi.org/10.1515/NCRS-2019-0385
SN  - 2196-7105
SN  - 2194-4946
VL  - 234
IS  - 6
SP  - 1255
EP  - 1257
PB  - De Gruyter
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Grunwald, Nicolas
A1  - Kelling, Alexandra
A1  - Holdt, Hans-Jürgen
A1  - Schilde, Uwe
T1  - The crystal structure of 1,1′-bisisoquinoline, C18H12N2
JF  - Zeitschrift für Kristallographie : international journal for structural, physical and chemical aspects of crystalline materials. New crystal structures
N2  - C18H12N2, tetragonal, I41/a (no. 88), a=13.8885(6) Å,
c=13.6718(6) Å, V =2637.2(3) Å3, Z =8, Rgt(F)=0.0295,
wRref(F2)=0.0854, T =210 K.
CCDC no.: 631823
Y1  - 2017
U6  - https://doi.org/10.1515/ncrs-2017-0088
VL  - 232
IS  - 5
SP  - 839
EP  - 841
PB  - de Gruyter
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Starke, Ines
A1  - Koch, Andreas
A1  - Kammer, Stefan
A1  - Holdt, Hans-Jürgen
A1  - Möller, Heiko Michael
T1  - Electrospray mass spectrometry and molecular modeling study of formation and stability of silver complexes with diazaperylene and bisisoquinoline
JF  - Journal of mass spectrometry
N2  - The complex formation of the following diazaperylene ligands (L) 1,12-diazaperylene 1, 1,1-bisisoquinoline 2, 2,11-disubstituted 1,12-diazaperylenes (alkyl=methyl, ethyl, isopropyl, 3, 5, 7), 3,3-disubstituted 1,1-bisisoquinoline (alkyl=methyl, ethyl, isopropyl, 4, 6, 8 and with R=phenyl, 11 and with pyridine 12), and the 5,8-dimethoxy-substituted diazaperylene 9, 6,6-dimethoxy-substituted bisisoquinoline 10 with AgBF4 was investigated. Collision-induced dissociation measurements were used to evaluate the relative stabilities of the ligands themselves and for the [1:1](+) complexes as well as for the homoleptic and heteroleptic silver [1:2](+) complexes in the gas phase. This method is very useful in rapid screening of the stabilities of new complexes in the gas phase. The influence of the spatial arrangement of the ligands and the type of substituents employed for the complexation were examined. The effect of the preorganization of the diazaperylene on the threshold activation voltages and thus of the relative binding energies of the different complexes are discussed. Density functional theory calculations were used to calculate the optimized structures of the silver complexes and compared with the stabilities of the complexes in the gas phase for the first time.
KW  - electrospray ionization mass spectrometry and modeling
KW  - silver(1) complexes
KW  - stability
Y1  - 2018
U6  - https://doi.org/10.1002/jms.4071
SN  - 1076-5174
SN  - 1096-9888
VL  - 53
IS  - 5
SP  - 408
EP  - 418
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Schwarze, Thomas
A1  - Riemer, Janine
A1  - Holdt, Hans-Jürgen
T1  - A Ratiometric Fluorescent Probe for K+ in Water Based on a Phenylaza-18-Crown-6 Lariat Ether
JF  - Chemistry - a European journal
N2  - This work presents two molecular fluorescent probes 1 and 2 for the selective determination of physiologically relevant K+ levels in water based on a highly K+/Na+ selective building block, the o-(2-methoxyethoxy)phenylaza-18-crown-6 lariat ether unit. Fluorescent probe 1 showed a high K+-induced fluorescence enhancement (FE) by a factor of 7.7 of the anthracenic emission and a dissociation constant (K-d) value of 38mm in water. Further, for 2+K+, we observed a dual emission behavior at 405 and 505nm. K+ increases the fluorescence intensity of 2 at 405nm by a factor of approximately 4.6 and K+ decreases the fluorescence intensity at 505nm by a factor of about 4.8. Fluorescent probe 2+K+ exhibited a K-d value of approximately 8mm in Na+-free solutions and in combined K+/Na+ solution a similar K-d value of about 9mm was found, reflecting the high K+/Na+ selectivity of 2 in water. Therefore, 2 is a promising fluorescent tool to measure ratiometrically and selectively physiologically relevant K+ levels.
KW  - charge transfer
KW  - crown compounds
KW  - fluorescence
KW  - potassium
KW  - ratiometric sensors
Y1  - 2018
U6  - https://doi.org/10.1002/chem.201802306
SN  - 0947-6539
SN  - 1521-3765
VL  - 24
IS  - 40
SP  - 10116
EP  - 10121
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Mickler, Wulfhard
A1  - Bukowsky, Heinz
A1  - Holdt, Hans-Jürgen
T1  - Separation of Palladium(II) with immobilized Maleonitrile-Dithiocrown ethers
N2  - Especially sulphur containing compounds are suitable for the separation of noble metals. 1,2-Dithioethenes are weak chelate-forming ligands and in the case of bis(methylthio)maleo-nitrile the donor power of both of the sulphur atoms is further decreased by the electron withdrawing effect of the cyanogroups. Crowned dithiomaleonitrile are macrocyclic chelate ligands which extract Pd(II) at sufficient rate in a very good yields. The synthesis of the immobilised ligands proceeds from the 2-allyloxy-1,2-propanediol forming the dicar-bon acid which is reduced to the diole. With the help of thionylchloride the dichloro compound is synthe-sized forming the macrocycle together with a dithiolate (1,2-disodium-1,2-dicyanethene-1,2-dithiolate, 1,2-disodium-4-methylbenzene-1,2-dithiolate) at high dilution conditions. The allylsubstituted crown ether is sillylated and the resulting alkoxysilane is immobilised onto activated silica gel. The extraction results with crown ethers are compared with that achieved with the help of substituted ß- diketones and 4-acyl-5-pyrazolones. By modification of the cavity of the macrocyclus the extraction rate increases from the acyclic compound through maleonitrile-dithio-21-crown-7, maleonitrile-dithio-15-crown-5 and maleonitrile-18-crown-6. The best results can be observed at the maleonitrile-dithio-12-crown-4. The rise of the function log D= f(log L) gives the composition of the extracted compounds as 1:1. The separa-tion is unsatisfactory in the case of Ag(I), Hg(II), Pt(II), Tl (I) and the most 3d-elements. Summarizing, a very good separation of palladium from the examined elements can be specified. Additional to the extraction experiments, as well as the crystal structures and by UV spectroscopy the for- mation constants of selected chelates were determined.
Y1  - 2002
ER  -