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Dr. Sandra Ast Tobias Fischer Holger Müller Dr. Wulfhard Mickler Mathias Schwichtenberg Dr. Knut Rurack Prof. Dr. Hans‐Jürgen Holdt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(9):2990-3005
In a systematic approach we synthesized a new series of fluorescent probes incorporating donor–acceptor (D‐A) substituted 1,2,3‐triazoles as conjugative π‐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 3 – 5 , 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. 相似文献
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Thomas Schwarze Wulfhard Mickler Dr. Carsten Dosche Dr. Roman Flehr Tillmann Klamroth Dr. Hans‐Gerd Löhmannsröben Prof. Dr. Peter Saalfrank Prof. Dr. Hans‐Jürgen Holdt Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(6):1819-1825
Fluoroionophores of fluorophore–spacer–receptor format were prepared for detection of PdCl2 by fluorescence enhancement. The fluorescent probes 1 – 13 consist of a fluorophore group, an alkyl spacer and a dithiomaleonitrile PdCl2 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 CH2‐bridged dithiomaleonitrile fluoroionophores. Second, fluorescent probes 4 – 9 containing two anthracene or pyrene fragments connected through CH2 bridges to the dithiomaleonitrile unit were synthesized. Modulation of the oxidation potential (EOx) through electron‐withdrawing or ‐donating groups on the anthracene moiety regulates the thermodynamic driving force for oxidative PET (ΔGPET) in bis(anthrylmethylthio)maleonitriles and therefore the fluorescence quantum yields (Φf), too. The new concept was confirmed and transferred to pyrenyl ligands, and fluorescence enhancements (FE) greater than 3.2 in the presence of PdCl2 were achieved by 7 and 8 (FE=5.4 and 5.2). Finally, for comparison, monofluorophore ligands 10 – 13 were synthesized. 相似文献
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Duha Jawad Awad Andreas Koch Wulfhard Mickler Uwe Schilde Prof. Dr. Peter Strauch 《无机化学与普通化学杂志》2012,638(6):965-975
A series of new heteroleptic MN2S2 transition metal complexes with M = Cu2+ for EPR measurements and as diamagnetic hosts Ni2+, Zn2+, and Pd2+ were synthesized and characterized. The ligands are N2 = 4, 4′‐bis(tert‐butyl)‐2, 2′‐bipyridine (tBu2bpy) and S2 =1, 2‐dithiooxalate, (dto), 1, 2‐dithiosquarate, (dtsq), maleonitrile‐1, 2‐dithiolate, or 1, 2‐dicyanoethene‐1, 2‐dithiolate, (mnt). The CuII complexes were studied by EPR in solution and as powders, diamagnetically diluted in the isostructural planar [NiII(tBu2bpy)(S2)] or[PdII(tBu2bpy)(S2)] as well as in tetrahedrally coordinated[ZnII(tBu2bpy)(S2)] host structures to put steric stress on the coordination geometry of the central CuN2S2 unit. The spin density contributions for different geometries calculated from experimental parameters are compared with the electronic situation in the frontier orbital, namely in the semi‐occupied molecular orbital (SOMO) of the copper complex, derived from quantum chemical calculations on different levels (EHT and DFT). One of the hosts, [NiII(tBu2bpy)(mnt)], is characterized by X‐ray structure analysis to prove the coordination geometry. The complex crystallizes in a square‐planar coordination mode in the monoclinic space group P21/a with Z = 4 and the unit cell parameters a = 10.4508(10) Å, b = 18.266(2) Å, c = 12.6566(12) Å, β = 112.095(7)°. Oxidation and reductions potentials of one of the host complexes, [Ni(tBu2bpy)(mnt)], were obtained by cyclovoltammetric measurements. 相似文献
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R. Cierpiszewski D. Rusińska-Roszak J. Szymanowski W. Mickler E. Uhlemann 《Journal of Radioanalytical and Nuclear Chemistry》1998,228(1-2):71-76
The rate of copper extraction with individual 4-acyl-5-pyrazolones and the stability of various enolic and keto forms and their monohydrates were studied. The rate of extraction depends mainly upon the structure of substituent at position 4 and falls when the substituent becomes spacy. The effect of the substituent at position 1 is rather low. The enolic form with intramolecular hydrogen bonding is the most stable. It can form hydrates with water molecules without intramolecular hydrogen bond breaking. 相似文献
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Heterodinuclear Ruthenium(II) Complexes of the Bridging Ligand 1,6,7,12‐Tetraazaperylene with Iron(II), Cobalt(II), Nickel(II), as well as Palladium(II) and Platinum(II) 下载免费PDF全文
Thomas Brietzke Alexandra Kelling Uwe Schilde Wulfhard Mickler Hans‐Jürgen Holdt 《无机化学与普通化学杂志》2016,642(1):8-13
The first heterodinuclear ruthenium(II) complexes of the 1,6,7,12‐tetraazaperylene (tape) bridging ligand with iron(II), cobalt(II), and nickel(II) were synthesized and characterized. The metal coordination sphere in this complexes is filled by the tetradentate N,N′‐dimethyl‐2,11‐diaza[3.3](2,6)‐pyridinophane (L‐N4Me2) ligand, yielding complexes of the general formula [(L‐N4Me2)Ru(µ‐tape)M(L‐N4Me2)](ClO4)2(PF6)2 with M = Fe {[ 2 ](ClO4)2(PF6)2}, Co {[ 3 ](ClO4)2(PF6)2}, and Ni {[ 4 ](ClO4)2(PF6)2}. Furthermore, the heterodinuclear tape ruthenium(II) complexes with palladium(II)‐ and platinum(II)‐dichloride [(bpy)2Ru(μ‐tape)PdCl2](PF6)2 {[ 5 ](PF6)2} and [(dmbpy)2Ru(μ‐tape)PtCl2](PF6)2 {[ 6 ](PF6)2}, respectively were also prepared. The molecular structures of the complex cations [ 2 ]4+ and [ 4 ]4+ were discussed on the basis of the X‐ray structures of [ 2 ](ClO4)4 · MeCN and [ 4 ](ClO4)4 · MeCN. The electrochemical behavior and the UV/Vis absorption spectra of the heterodinuclear tape ruthenium(II) complexes were explored and compared with the data of the analogous mono‐ and homodinuclear ruthenium(II) complexes of the tape bridging ligand. 相似文献
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Gwendolyn Cramer Robert Lewis Ashley Gymarty Sarah Hagan Michela Mickler Sydney Evans Salman R. Punekar Lee Shuman Charles B. Simone II Stephen M. Hahn Theresa M. Busch Douglass Fraker Keith A. Cengel 《Photochemistry and photobiology》2020,96(3):684-691
Peritoneal carcinomatosis (PC) can occur as an advanced consequence of multiple primary malignancies. Surgical resection, radiation or systemic interventions alone have proven inadequate for this aggressive cancer presentation, since PC still has a poor survival profile. Photodynamic therapy (PDT), in which photosensitive drugs are exposed to light to generate cytotoxic reactive oxygen species, may be an ideal treatment for PC because of its ability to deliver treatment to a depth appropriate for peritoneal surface tumors. Additionally, epidermal growth factor receptor (EGFR) signaling plays a variety of roles in cancer progression and survival as well as PDT-mediated cytotoxicity, so EGFR inhibitors may be valuable in enhancing the therapeutic index of intraperitoneal PDT. This study examines escalating doses of benzoporphyrin derivative (BPD)-mediated intraperitoneal PDT combined with the EGFR-inhibitor cetuximab in a canine model. In the presence or absence of small bowel resection (SBR) and cetuximab, we observed a tolerable safety and toxicity profile related to the light dose received. Additionally, our findings that BPD levels are higher in the small bowel compared with other anatomical regions, and that the risk of anastomotic failure decreases at lower light doses will help to inform the design of similar PC treatments in humans. 相似文献
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(Separation of copper from ammoniacal solutions by liquid-liquid-extraction and liquid membrane technique with 1-phenyl-3-methyl-4-stearoylpyrazol-5-one.) The separation of copper with 1-phenyl-3-methyl-4-stearoyl-pyrazol-5-one by liquid-liquid extraction and liquid-membrane permeation is reported. The ligand is able to separate Cu(II) as CuL2 from alkaline and ammoniacal solutions, respectively. The influence of pH, concentration of ammonia, concentration of salts contained and of the carriers, respectively, composition of the membrane phase and the initial copper concentration are studied. The parameters of the extraction are given. Because of the comparatively small solubility of the copper complex, the industrial application of the ligand is useful only for diluted solutions. 相似文献
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S Kammer I Starke A Pietrucha A Kelling W Mickler U Schilde C Dosche E Kleinpeter HJ Holdt 《Dalton transactions (Cambridge, England : 2003)》2012,41(34):10219-10227
A series of new monocationic iridium(iii) complexes [Ir(C^N)(2)(N^N)]PF(6) with "large-surface"α,α'-diimin ligands N^N (dap = 1,12-diazaperylene, dmedap = 2,11-dimethyl-1,12-diazaperylene, dipdap = 2,11-diisopropyl-1,12-diazaperylene) and different cyclometalating ligands C^N (piq = 1-phenylisoquinoline, bzq = benzo[h]quinoline, ppz = 1-phenylpyrazole, thpy = 2-(2-thienyl)pyridine, ppy = 2-phenylpyridine, meppy = 2-(4-methylphenyl)pyridine, dfppy = 2-(2,4-difluorophenyl)pyridine) were synthesized. The solid structures of the complexes [Ir(piq)(2)(dap)]PF(6), [Ir(bzq)(2)(dap)]PF(6), [Ir(ppy)(2)(dipdap)]PF(6), [Ir(piq)(2)(dmedap)]PF(6), [Ir(ppy)(2)(dap)]PF(6) and [Ir(ppz)(2)(dap)]PF(6) are reported. In [Ir(piq)(2)(dap)]PF(6), the dap ligand and one of the piq ligands of each cationic complex are involved in π-π stacking interactions forming supramolecular channels running along the crystallographic c axis. In the crystalline [Ir(bzq)(2)(dap)]PF(6)π-π stacking interactions between the metal complexes lead to the formation of a 2D layer structure. In addition, CH-π interactions were found in all compounds, which are what stabilizes the solid structure. In particular, a significant number of them were found in [Ir(piq)(2)(dap)]PF(6) and [Ir(bzq)(2)(dap)]PF(6). The crystal structures of [Ir(ppy)(2)(dipdap)]PF(6) and [Ir(ppy)(2)(dmedap)]PF(6) are also presented, being the first examples of bis-cyclometalated iridium(iii) complexes with phenanthroline-type α,α'-diimin ligands bearing bulky alkyl groups in the neighbourhood of the N-donor atoms. These ligands implicate a distorted octahedral coordination geometry that in turn destabilized the Ir-N(N^N) bonds. The new iridium(iii) complexes are not luminescent. All compounds show an electrochemically irreversible anodic peak between 1.15 and 1.58 V, which is influenced by the different cyclometalated ligands. All of the new complexes show two reversible successive one-electron "large-surface" ligand-centred reductions around -0.70 V and -1.30 V. Electrospray ionisation mass spectrometry (ESI-MS) and collision induced decomposition (CID) measurements were used to investigate the stability of the new complexes. Thereby, the stability agreed well with the order of the Ir-N(N^N) bond lengths. 相似文献