TY  - JOUR
A1  - Strauch, Peter
A1  - Neumann, Mike
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
T1  - Bis(1,2-dithiosquarato)nickelates(II): Synthesis, Structure, EPR and Thermal Behavior
JF  - Acta chimica Slovenica
N2  - 1,2-Dithiosquaratonickelates are available by direct synthesis from metal salts with dipotassium-1,2-dithiosquarate and the appropriate counter cations. The synthesis and characterization, including mass spectrometry, of a series 1,2-dithiosquaratonickelates(II), [Ni(dtsq)(2)](2-), with several "onium" cations is reported and the X-ray structures of two diamagnetic complexes, (HexPh(3)P)(2)[Ni(dtsq)(2)] and (BuPh3P)(2)[Ni(dtsq)(2)] with sterically demanding counter ions are presented. The diamagnetic nickel complexes have been doped as host lattices with traces of Cu(II) to measure EPR for additional structural information. The thermal behavior of this series is studied by thermogravimetry and differential thermal analysis (TG/DTA). The thermolysis in air as well as under nitrogen atmosphere of these complexes results in nickel oxide nano-particles in all cases, which are characterized by X-ray powder diffraction.
KW  - 1,2-Dithiosquarate,1,2-Dithiosquaratonickelate
KW  - X-ray structure
KW  - TG/DTA
KW  - Nickel oxide
KW  - EPR spectroscopy
Y1  - 2015
SN  - 1318-0207
SN  - 1580-3155
VL  - 62
IS  - 2
SP  - 288
EP  - 296
PB  - Drustvo
CY  - Ljubljana
ER  - 
TY  - JOUR
A1  - Strauch, Peter
A1  - Kossmann, Alexander
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
T1  - EPR on bis(1,2-dithiosquarato)cuprate(II) in the bis(1,2-dithiosquarato)nickelate(II) host lattice - structure and spectroscopy
JF  - Chemical papers
N2  - EPR spectroscopy is a well suited analytical tool to monitor the electronic situation around paramagnetic metal centres as copper(II) and therefore the structural influences on the paramagnetic ion. 1,2-Dithiosquaratometalates are available by direct synthesis from metal salts with dipotassium-1,2-dithiosquarate and the appropriate counter cations. Synthesis and characterisation of bis(benzyltributylammonium)1,2-dithiosquaratonickelate(II), (BzlBu(3)N)(2)[Ni(dtsq)(2)], and bis(benzyltributylammonium)1,2-dithiosquaratocuprate(II), (BzlBu(3)N)(2)[Cu(dtsq)(2)], with benzyltributylammonium as the counter ion is reported and the X-ray structures of two complexes, (BzlBu(3)N)(2)[Ni(dtsq)(2)] and (BzlBu(3)N)(2)[Cu(dtsq)(2)], are presented. Both complexes, crystallising in the monoclinic space group P2(1)/c, are isostructural with only small differences in the coordination sphere due to the different metal ions. The diamagnetic nickel complex is therefore well suited as a host lattice for the paramagnetic Cu(II) complex to measure EPR for additional structural information. (c) 2015 Institute of Chemistry, Slovak Academy of Sciences
KW  - 1,2-dithiosquarate
KW  - 1,2-dithiosquaratometalate
KW  - X-ray structure
KW  - EPR spectroscopy
Y1  - 2016
U6  - https://doi.org/10.1515/chempap-2015-0154
SN  - 0366-6352
SN  - 1336-9075
VL  - 70
SP  - 61
EP  - 68
PB  - De Gruyter
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Geroldinger, Gerald
A1  - Tonner, Matthias
A1  - Fudickar, Werner
A1  - De Sarkar, Sritama
A1  - Dighal, Aishwarya
A1  - Monzote, Lianet
A1  - Staniek, Katrin
A1  - Linker, Torsten
A1  - Chatterjee, Mitali
A1  - Gille, Lars
T1  - Activation of anthracene endoperoxides in leishmania and impairment of mitochondrial functions
JF  - Molecules
N2  - Leishmaniasis is a vector-borne disease caused by protozoal Leishmania. Because of resistance development against current drugs, new antileishmanial compounds are urgently needed. Endoperoxides (EPs) are successfully used in malaria therapy, and experimental evidence of their potential against leishmaniasis exists. Anthracene endoperoxides (AcEPs) have so far been only technically used and not explored for their leishmanicidal potential. This study verified the in vitro efficiency and mechanism of AcEPs against both Leishmania promastigotes and axenic amastigotes (L. tarentolae and L. donovani) as well as their toxicity in J774 macrophages. Additionally, the kinetics and radical products of AcEPs’ reaction with iron, the formation of radicals by AcEPs in Leishmania, as well as the resulting impairment of parasite mitochondrial functions were studied. Using electron paramagnetic resonance combined with spin trapping, photometry, and fluorescence-based oximetry, AcEPs were demonstrated to (i) show antileishmanial activity in vitro at IC50 values in a low micromolar range, (ii) exhibit host cell toxicity in J774 macrophages, (iii) react rapidly with iron (II) resulting in the formation of oxygen- and carbon-centered radicals, (iv) produce carbon-centered radicals which could secondarily trigger superoxide radical formation in Leishmania, and (v) impair mitochondrial functions in Leishmania during parasite killing. Overall, the data of different AcEPs demonstrate that their structures besides the peroxo bridge strongly influence their activity and mechanism of their antileishmanial action.
KW  - Leishmania
KW  - endoperoxides
KW  - EPR spectroscopy
KW  - mitochondria
KW  - radicals
Y1  - 2018
U6  - https://doi.org/10.3390/molecules23071680
SN  - 1420-3049
VL  - 23
IS  - 7
PB  - MDPI
CY  - Basel
ER  -