Russian Journal of Organic Chemistry - New data since about 2010 concerning complex formation of phosphorus-containing cyclophanes and cryptands with transition metals, as well as guest-host... 相似文献
A graph is -choosable if the following holds: For any list assignment which assigns to each vertex a set of real numbers, and assigns to each edge a set of real numbers, there is a total weighting such that for , and for every edge . This paper proves that if is a connected graph of maximum degree , then is -choosable. 相似文献
Optics and Spectroscopy - Studies published in the period from 2014 to 2018 that are aimed at creating nondispersive and photoacoustic IR gas analyzers with LED radiation sources based on... 相似文献
The behavior of group-4 homologs Zr and Hf on extraction-chromatographic sorbents LN resin and TRU resin in mixtures of HF and HNO3 is considered. Distribution coefficients of the elements in the mixtures of 5·10−4 M–1 M HF and 0.01 M–5 M HNO3 are determined. Strong retention of both elements was found on LN resin in the range of concentrations c(HF) ≤ 0.01 M for all concentrations of HNO3. Retention tends to gradually disappear while increasing c(HF) to 0.5 M. On TRU resin retention is observed only in solutions with c(HNO3) ≥ 2 M and c(HF) ≤ 0.01 M. The possibility of separating Zr(IV) and Hf(IV) on LN resin is illustrated in two different acid mixtures, whereas their separation on TRU resin under the conditions studied in this work is difficult. The results obtained can be used to isolate analytes from multicomponent mixtures during analytical tasks, as well as to separate them from each other.
Optics and Spectroscopy - The bioavailability improvement of hydrophobic drugs is one of the major problems in pharmaceutical research as required for the enhancement of their therapeutic efficacy.... 相似文献
A new asymmetric Salamo‐based ligand H2L was synthesized using 3‐tert‐butyl‐salicylaldehyde and 6‐methoxy‐2‐[O‐(1‐ethyloxyamide)]‐oxime‐1‐phenol. By adjusting the ratio of the ligand H2L and Cu (II), Co (II), and Ni (II) ions, mononuclear, dinuclear, and trinuclear transition metal (II) complexes, [Cu(L)], [{Co(L)}2], and [{Ni(L)(CH3COO)(CH3CH2OH)}2Ni] with the ligand H2L possessing completely different coordination modes were obtained, respectively. The optical spectra of ligand H2L and its Cu (II), Co (II) and Ni (II) complexes were investigated. The Cu (II) complex is a mononuclear structure, and the Cu (II) atom is tetracoordinated to form a planar quadrilateral structure. The Co (II) complex is dinuclear, and the two Co (II) atoms are pentacoordinated and have coordination geometries of distorted triangular bipyramid. The Ni (II) complex is a trinuclear structure, and the terminal and central Ni (II) atoms are all hexacoordinated, forming distorted octahedral geometries. Furthermore, optical properties including UV–Vis, IR, and fluorescence of the Cu (II), Co (II), and Ni (II) complexes were investigated. Finally, the antibacterial activities of the Cu (II), Co (II), and Ni (II) complexes were explored. According to the experimental results, the inhibitory effect was found to be enhanced with increasing concentrations of the Cu (II), Co (II), and Ni (II) complexes. 相似文献