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Monatshefte Für Chemie

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https://www.readbyqxmd.com/read/27881885/acyclic-nucleoside-phosphonates-containing-the-amide-bond
#1
Iwona E Głowacka, Dorota G Piotrowska, Graciela Andrei, Dominique Schols, Robert Snoeck, Andrzej E Wróblewski
ABSTRACT: To study the influence of a linker rigidity and donor-acceptor properties, the P-CH2-O-CHR- fragment in acyclic nucleoside phosphonates (e.g., acyclovir, tenofovir) was replaced by the P-CH2-HN-C(O)- residue. The respective phosphonates were synthesized in good yields by coupling the straight chain of ω-aminophosphonates and nucleobase-derived acetic acids with EDC. Based on the (1)H and (13)C NMR data, the unrestricted rotation within the methylene and 1,2-ethylidene linkers in phosphonates from series a and b was confirmed...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27795584/copper-ii-complexes-with-imino-phenoxide-ligands-synthesis-characterization-and-their-application-as-catalysts-for-the-ring-opening-polymerization-of-rac-lactide
#2
Mrinmay Mandal, Kerstin Oppelt, Manuela List, Ian Teasdale, Debashis Chakraborty, Uwe Monkowius
ABSTRACT: Four new copper complexes based on bidentate imino phenoxide ligands were synthesized and characterized by IR, UV-Vis spectroscopy, ESI mass spectrometry, single crystal X-ray diffraction, and electrochemistry. The crystal structures revealed that the copper(II) atoms are surrounded by phenolate oxygen and imine nitrogen atoms of two ligands in a distorted square-planar geometry. The existence of ligand-centered, as well as Cu(II)-centered quasi-reversible and reversible redox reactions are observed in the cyclic voltammetry experiments of all the complexes...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27795583/synthesis-characterization-and-antioxidant-activity-of-zn-2-and-cu-2-coordinated-polyhydroxychalcone-complexes
#3
Chiara Sulpizio, Simon T R Müller, Qi Zhang, Lothar Brecker, Annette Rompel
ABSTRACT: Four new metal complexes [Cu(ISO)2], [Cu(BUT)2] and [Zn(ISO)2], [Zn(BUT)2] of the polyhydroxychalcones (isoliquiritigenin and butein) are synthesized, structurally characterized and their antioxidant activity is investigated. The formation of the complexes [Cu(ISO)2] and [Zn(ISO)2] is followed by Job's plot using NMR titration. The resulting compounds are characterized by mass spectrometry, IR spectroscopy, and elemental analysis. Studies on the radical scavenging activity are performed using DPPH as substrate...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27729714/synthesis-of-polybrominated-benzimidazole-and-benzotriazole-derivatives-containing-a-tetrazole-ring-and-their-cytotoxic-activity
#4
Edyta Łukowska-Chojnacka, Patrycja Wińska, Monika Wielechowska, Maria Bretner
ABSTRACT: A series of new benzimidazole and benzotriazole derivatives containing a tetrazole moiety was synthesized by N-alkylation of 5-aryltetrazole with 4,5,6,7-tetrabromo-1-(3-chloropropyl)-1H-benzimidazole and 4,5,6,7-tetrabromo-2-(3-chloropropyl)-2H-benzotriazole. The reaction was regioselective and mostly 2,5-disubstituted tetrazole derivatives were obtained. The effect of all synthesized compounds on human recombinant casein kinase 2alpha subunit (rhCK2α) and cytotoxicity against human T-cell lymphoblast (CCRF-CEM) and breast adenocarcinoma (MCF-7) cell lines were evaluated...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27729713/synthesis-structure-and-antioxidant-activity-of-methoxy-and-hydroxyl-substituted-2-aminochalcones
#5
Chiara Sulpizio, Alexander Roller, Gerald Giester, Annette Rompel
ABSTRACT: Three 2'-aminochalcone derivatives (E)-1-(2-aminophenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one, (E)-1-(2-aminophenyl)-3-(3,4-dihydroxyphenyl)prop-2-en-1-one, and (E)-1-(2-amino-4,5-dimethoxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-one, have been synthesized, characterized, and tested in vitro in order to assess their antioxidant activity. All compounds were characterized on the basis of (1)H NMR, (13)C NMR, ESI-mass spectrometry, FT-IR, UV/Vis, and elemental analysis. The X-ray crystal structures of (E)-1-(2-aminophenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one and (E)-1-(2-amino-4,5-dimethoxyphenyl)-3-(4-methoxyphenyl)prop-2-en-1-one were successfully determined showing a planar molecule geometry...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27729712/synthesis-and-characterization-of-cationic-dicarbonyl-fe-ii-pnp-pincer-complexes
#6
Mathias Glatz, Christian Schröder-Holzhacker, Bernhard Bichler, Berthold Stöger, Kurt Mereiter, Luis F Veiros, Karl Kirchner
ABSTRACT: In the present work, we have prepared a series of octahedral Fe(II) complexes of the type trans-[Fe(PNP)(CO)2Cl](+)-PNP are tridentate pincer-type ligands based on 2,6-diaminopyridine. These complexes are formed irrespective of the size of the substituents at the phosphorus sites and whether cis-[Fe(PNP)(Cl2)(CO)] or trans-[Fe(PNP)(Cl2)(CO)] are reacted with CO in the presence of 1 equiv of silver salts. X-ray structures of representative complexes are presented. Based on simple bonding considerations the selective formation of trans-dicarbonyl Fe(II) complexes is unexpected...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27729711/bias-induced-conductance-switching-in-single-molecule-junctions-containing-a-redox-active-transition-metal-complex
#7
Georg Kastlunger, Robert Stadler
ABSTRACT: The paper provides a comprehensive theoretical description of electron transport through transition metal complexes in single molecule junctions, where the main focus is on an analysis of the structural parameters responsible for bias-induced conductance switching as found in recent experiments, where an interpretation was provided by our simulations. The switching could be theoretically explained by a two-channel model combining coherent electron transport and electron hopping, where the underlying mechanism could be identified as a charging of the molecule in the junction made possible by the presence of a localized electronic state on the transition metal center...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27546911/high-spin-iron-ii-complexes-with-mono-phosphorylated-2-6-diaminopyridine-ligands
#8
Christan Schröder-Holzhacker, Berthold Stöger, Ernst Pittenauer, Günther Allmaier, Luis F Veiros, Karl Kirchner
ABSTRACT: Several new monophosphorylated 2,6-diaminopyridine ligands bearing PiPr2 and PtBu2 units (PN(NH2)-iPr, PN(NH2)-tBu, PN(NHMe)-iPr, and PN(NHEt)-iPr) are prepared by treatment of the respective 2,6-diaminopyridines with the chlorophosphines PiPr2Cl and PtBu2Cl in the presence of a base. Treatment of anhydrous FeCl2 with 1 equiv of these afforded the tetracoordinated coordinatively unsaturated 14e(-) complexes [Fe(κ(2) P,N-PN(NH2)-iPr)Cl2] and [Fe(κ(2) P,N-PN(NH2)-tBu)Cl2], while with PN(NHMe)-iPr and PN(NHEt)-iPr a phosphine transfer reaction of a second PN ligand took place to yield the known PNP pincer complexes [Fe(κ(3) P,N,P-PNP(Me)-iPr)Cl2] and [Fe(κ(3) P,N,P-PNP(Et)-iPr)Cl2]...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27546910/in-vitro-digestion-method-for-estimation-of-copper-bioaccessibility-in-a%C3%A3-a%C3%A3-berry
#9
Lena Ruzik, Justyna Wojcieszek
ABSTRACT: Copper is an essential trace element for humans and its deficiency can lead to numerous diseases. A lot of mineral supplements are available to increase intake of copper. Unfortunately, only a part of the total concentration of elements is available for human body. Thus, the aim of the study was to determine bioaccessibility of copper in Açai berry, known as a "superfood" because of its antioxidant qualities. An analytical methodology was based on size exclusion chromatography (SEC) coupled to a mass spectrometer with inductively coupled plasma (ICP MS) and on capillary liquid chromatography coupled to tandem mass spectrometer with electrospray ionization (µ-HPLC-ESI MS/MS)...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27546909/determination-of-mdpbp-in-postmortem-blood-samples-by-gas-chromatography-coupled-with-mass-spectrometry
#10
Marek Wiergowski, Mateusz K Woźniak, Marzena Kata, Marek Biziuk
ABSTRACT: MDPBP (1-(3,4-methylenedioxyphenyl)-2-(1-pyrrolidinyl)-1-butanone) is a new psychoactive substance sold on the black market. It has been a controlled drug of abuse in Poland and China since 2015 as some toxic and fatal cases connected with use of synthetic cathinone derivatives were observed. The fatal case outlined here concerns a 19-year-old man, who was found dead with an envelope containing white powder lying nearby the cadaver. The analyses of the powder revealed a presence of MDPBP...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27546908/the-use-of-hplc-q-tof-ms-for-comprehensive-screening-of-drugs-and-psychoactive-substances-in-hair-samples-and-several-legal-highs-products
#11
Justyna Aszyk, Agata Kot-Wasik
ABSTRACT: Non-targeted screening of drugs present in herbal products, known as "legal high" drugs and in hair as a biological matrix commonly used in toxicological investigations was accomplished with the use of high pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). In total, 25 and 14 therapeutical drugs and psychoactive substances/metabolites were detected in investigated hair samples and herbal products, respectively. We demonstrate that the HPLC-Q-TOF methodology seems to be a powerful tool in the qualitative analysis applied in identification of these designer drugs, thus enabling a laboratory to stay-up-to-date with the drugs that are being sold as legal high products on black market...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27546907/determination-of-selected-chemical-parameters-in-surface-water-samples-collected-from-the-revelva-catchment-hornsund-fjord-svalbard
#12
Klaudia Kosek, Żaneta Polkowska
ABSTRACT: Surface water samples (river and lake) were collected from the Revelva catchment every summer from 2010 to 2013. This study concerns importance of the use of some analytical techniques for pollutants and parameters determination in Arctic environmental samples based on the example of total organic carbon, phenols, and formaldehyde determination and measurement of pH and electrical conductivity parameters. Significant average concentration levels of formaldehyde were observed in 2012 and reached 0...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27358502/first-example-of-stepwise-zwitterionic-mechanism-for-bicyclo-2-2-1-hept-5-ene-norbornene-formation-process-catalyzed-by-the-1-butyl-3-methylimidazolium-cations
#13
Radomir Jasiński
ABSTRACT: B3LYP/6-31++G(d) calculations indicated that the reaction of (2E)-3-phenyl-2-nitroprop-2-enenitrile with cyclopentadiene catalyzed by cations of 1,3-dialkylimidazolium ionic liquid shall not take place according to the classical scheme of one-step [2+4] Diels-Alder cycloaddition. Along the path finally leading to bicyclo[2.2.1]hept-5-ene (norbornene) with a nitro group in endo orientation, the process of bicarbocyclic skeleton formation shall take place according to the domino mechanism, via [2+4] heterocycloadduct...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27358501/a-chromium-tricarbonyl-complex-featuring-the-4-6-bis-diphenylphosphinomethyl-dibenzothiophene-psp-ph-ligand
#14
Matthias Mastalir, Clara Schweinzer, Matthias Weil, Ernst Pittenauer, Günter Allmaier, Karl Kirchner
ABSTRACT: The new PSP pincer ligand 4,6-bis(diphenylphosphinomethyl)dibenzothiophene (PSP(Ph)) was prepared in 89 % yield. With this ligand, a solvothermal synthesis of a Cr complex of the type [Cr(κ(3) P,S,P-PSP)(CO)3] is described. The X-ray structure of this compound is presented. We demonstrate that the solvothermal synthesis technique provides a powerful, simple, and practical synthetic method resulting in a high isolated yield in a short reaction time. GRAPHICAL ABSTRACT: HASH(0x3d1dcd0) ...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27340298/new-indenylidene-type-metathesis-catalysts-bearing-unsymmetrical-n-heterocyclic-ligands-with-mesityl-and-nitrobenzyl-substituents
#15
Marta Malinowska, Mariana Kozlowska, Agnieszka Hryniewicka, Stanisław Witkowski, Jacek W Morzycki
ABSTRACT: New indenylidene-type second generation catalysts bearing modified unsymmetrically substituted N-heterocyclic carbene ligands were synthesized. The complexes contain an N-mesityl and N'-nitrobenzyl substituted NHC ligand. The precursors of free carbenes-imidazolinium salts-were obtained in an easy and environment-friendly way (under aqueous or neat conditions). The new catalysts were prepared by reaction of in situ generated carbenes with a 1st generation indenylidene catalyst, containing pyridine ligands instead of tricyclohexylphosphine...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27340297/synthesis-and-reactivity-of-binepine-based-chiral-fe-ii-pnp-pincer-complexes
#16
Christian Schröder-Holzhacker, Nikolaus Gorgas, Berthold Stöger, Karl Kirchner
ABSTRACT: A new asymmetric chiral PNP ligand based on the 2,6-diaminopyridine scaffold featuring a R-BINEPINE moiety was prepared. Treatment of anhydrous FeX2 (X = Cl, Br) with 1 equiv of PNP-iPr,BIN at room temperature afforded the coordinatively unsaturated paramagnetic complexes [Fe(PNP-iPr,BIN)X2]. The structure of [Fe(PNP-iPr,BIN)Cl2] is described. Both complexes react readily with the strong π-acceptor ligand CO in solution to afford selectively the diamagnetic complexes trans-[Fe(PNP-iPr,BIN)(CO)X2] in quantitative yield...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27226652/synthesis-spectroscopic-and-crystallographic-analysis-of-the-zn-complex-of-a-di-%C3%AE-%C3%AE-sulfoleno-pyrrin-model-for-zn-complexes-of-bilirubin-and-of-phylloxanthobilins
#17
Chengjie Li, Klaus Wurst, Yaqing Feng, Bernhard Kräutler
ABSTRACT: A high yield preparation, spectroscopic and crystallographic investigation of the crystalline Zn-complex of a di(β,β'-sulfoleno)pyrrin are reported here. In the brightly green fluorescent Zn-complex of the hardly luminescent di(β,β'-sulfoleno)pyrrin, the metal ion is bound by two di(β,β'-sulfoleno)pyrrin ligands, as revealed first by its mass spectra. The crystal structure of this Zn-complex of the di(β,β'-sulfoleno)pyrrin confirmed a regular 2:1 composition of the bidentate di(β,β'-sulfoleno)pyrrin ligand and the metal ion...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27226651/a-thermodynamic-study-of-the-cadmium-neodymium-system
#18
Barbara Skołyszewska-Kühberger, Thomas L Reichmann, Herbert Ipser
ABSTRACT: Cd vapor pressures were determined over Cd-Nd samples by an isopiestic method. The measurements were carried out in the temperature range from about 690 to 1200 K and over a composition range between 48 and 92 at % Cd. From the vapor pressures, thermodynamic activities of Cd were derived for all samples at their respective sample temperatures, and partial molar enthalpies of Cd were obtained from the temperature dependence of the activities. With these partial molar enthalpies, the Cd activities were converted to a common temperature of 873 K...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27110041/electrochemical-dissolution-of-steel-as-a-typical-catalyst-for-electro-fenton-oxidation
#19
Veronika Kočanová, Libor Dušek
ABSTRACT: Although traditional Fenton reaction is known for a long time, it is still a perspective method for removal of pollution from wastewater. Applications of electro-Fenton oxidation are commonly used in wastewater treatment. These methods are classified into groups-electrochemical advanced oxidation processes. Typical catalysts for these technologies are Fe(2+) ions. Comparison between two material types of steel was investigated in this paper. Alloy steel Cr-Ni and non-alloy steel were used as a source of Fe(2+) ions as catalyst for electro-Fenton oxidation...
2016: Monatshefte Für Chemie
https://www.readbyqxmd.com/read/27110040/induced-expression-of-microsomal-cytochrome-b-5-determined-at-mrna-and-protein-levels-in-rats-exposed-to-ellipticine-benzo-a-pyrene-and-1-phenylazo-2-naphthol-sudan-i
#20
Marie Stiborová, Michaela Moserová, Iveta Mrízová, Helena Dračínská, Václav Martínek, Radek Indra, Eva Frei, Vojtěch Adam, René Kizek, Heinz H Schmeiser, Kateřina Kubáčková, Volker M Arlt
ABSTRACT: The microsomal protein cytochrome b 5 , which is located in the membrane of the endoplasmic reticulum, has been shown to modulate many reactions catalyzed by cytochrome P450 (CYP) enzymes. We investigated the influence of exposure to the anticancer drug ellipticine and to two environmental carcinogens, benzo[a]pyrene (BaP) and 1-phenylazo-2-naphthol (Sudan I), on the expression of cytochrome b 5 in livers of rats, both at the mRNA and protein levels. We also studied the effects of these compounds on their own metabolism and the formation of DNA adducts generated by their activation metabolite(s) in vitro...
2016: Monatshefte Für Chemie
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