ABSTRACT
An interaction of M(hfac)2 (M = Mn or Ni) with N-(bis(4,4,5,5-tetramethyl-3-oxido-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)methylene)-2-methyl-propan-2-amine oxide (a nitronyl nitroxide diradical with the >C[double bond, length as m-dash]N(O)-tert-Bu coupler) was investigated under various conditions. It was found that prolongation of reaction time caused transformation of the initial diradical into new diradicals with the unique >C[double bond, length as m-dash]N-OH coupling unit and formation of binuclear Mn(ii) and Ni(ii) complexes, which were characterized by X-ray diffraction analysis. The resulting binuclear heterospin complexes have a complicated magnetic structure with six paramagnetic centers and a number of exchange interaction channels between them, as well as between neighboring complexes. To adequately describe the magnetic properties of these complexes, high-level ab initio calculations of their electronic structure and parameters of the spin-Hamiltonian were carried out. The accuracy of the conventional broken-symmetry density functional theory approach in the calculation of the exchange interaction parameters was also verified.
ABSTRACT
The author name M. V. Edeeva should read M. V. Edeleva.
ABSTRACT
Effect of alkoxyamines on normal and tumor cells was studied in vitro and in vivo. In vitro experiments showed that alkoxyamines produce a dose-dependent toxic effect on cells of human breast tumor MCF7 line. Transplantation of Krebs-2 ascites carcinoma cells preincubated with alkoxyamines to mice did not induce tumor growth. An opposite effect was observed in normal mouse cells: functional activity of peritoneal macrophages increased. The possibility of using alkoxyamines as theranostic agents is discussed.
Subject(s)
Antineoplastic Agents/pharmacology , Hydroxylamines/pharmacology , Animals , Cell Survival/drug effects , Drug Screening Assays, Antitumor , Humans , Inhibitory Concentration 50 , MCF-7 Cells , Macrophages, Peritoneal/drug effects , Macrophages, Peritoneal/physiology , Male , Mice , Mice, Inbred CBA , Neoplasm Transplantation , Phagocytosis/drug effectsABSTRACT
Although light-induced magnetostructural switching in copper(II)-nitroxide molecular magnets Cu(hfac)2L(R) has been known for several years, structural characterization of metastable photoinduced states has not yet been accomplished due to significant technical demands. In this work we apply, for the first time, variable-temperature FTIR spectroscopy with photoexcitation to investigate the structural specifics of light-induced states in the Cu(hfac)2L(R) family represented by (i) Cu(hfac)2L(Me) comprising two-spin copper(II)-nitroxide clusters, and (ii) Cu(hfac)2L(Pr) comprising three-spin nitroxide-copper(II)-nitroxide clusters. The light-induced state of Cu(hfac)2L(Me) manifests the same set of vibrational bands as the corresponding thermally-induced state, implying their similar structures. For the second compound Cu(hfac)2L(Pr), the coordination environment of copper(II) is similar in light- and thermally-induced states, but distinct differences are found for packing of the peripheral n-propyl substituent of nitroxide. Thus, generally the structures of the corresponding thermally- and light-induced states in molecular magnets Cu(hfac)2L(R) might differ, and FTIR spectroscopy provides a useful approach for revealing and elucidating such differences.
