A series of oligogermanes, (Me 3 Si) 3 GeGeCl 3 , (C 6 F 5 ) 3 GeGePh 3 , (C 6 F 5 ) 3 GeGe(p-Tol) 3 , and (C 6 F 5 ) 2 Ge[Ge(p-Tol) 3 ] 2 , containing substituents with different electronic properties at neighboring germanium atoms were synthesized. According to X-ray diffraction studies, UV/visible spectroscopy, and quantum chemical calculations, these "donor−acceptor" oligogermanes are characterized by energies of electronic transitions lower than those for other similar compounds.
Two series of germanium compounds, (pTol) 3 Ge-MMe 3 (M = Si (1), Ge (2), Sn (3)) and (Me 3 Si) 3 Ge-MPh 3 (M = Ge (4), Sn (5)), were prepared using lithium or potassium intermediates. The changing of the reaction conditions results in trigermane Ph 3 Ge-Ge(SiMe 3 ) 2 -GePh 3 (6). The molecular structures of 1, 2, and 6 were investigated by X-ray analysis. By UV/visible spectroscopy it is established that introduction of a tin atom results in a significant bathochromic absorption shift. Furthermore, according to cyclic voltammetry, oxidation potentials decrease in the order 1 > 2 > 3. The electronic structures of 1−4 and related (Me 3 Si) 3 GeSiPh 3 were investigated by DFT calculations. Fluorescence properties of 1−3 were studied in the solid state and in solution; for compound 3 phosphorescence (lifetime is 4.58 ms) is observed in the solid state.
A series of Zn, Mn, Fe, Co, and Ni complexes ([MX2L], X = Cl, OAc) of the novel di-(2-picolyl)amine ligand L with an antioxidant 2,6-di-tert-butylphenol pendant were synthesized and characterized by elemental analysis, IR, multinuclear NMR spectroscopy, MALDI-TOF mass spectrometry and the molecular structures of [ZnCl2L] and [MnCl2L] were established by X-ray crystallography. The chemical oxidation of complexes with a 2,6-di-tert-butylphenol fragment to the phenoxyl radicals was studied by means of ESR method. The antioxidant radical scavenging activity of the complexes was measured spectrophotometrically using a DPPH-test and linoleic acid peroxidation. The electron transfer reactions were examined in CUPRAC tests and as the inhibition of an enzymatic reaction involving the generation of a reactive oxygen species (superoxide radical-anion) by xanthine oxidase. The lipoxygenase (LOX) inhibition activity of the studied compounds was evaluated. The in vitro biological experiments were performed by using rat brain homogenates. The role of the phenol fragment and metal was found to be essential in antioxidant activity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.