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排序方式: 共有163条查询结果,搜索用时 15 毫秒
41.
Peter Baran Raphael G. Raptis Abimael D. Rodríguez Ileana I. Rodríguez Yan-Ping Shi 《Journal of chemical crystallography》2003,33(9):711-718
X-ray structures of Elisabatin B (1) and Elisabatin C (2) have been determined. Crystal data for 1: Triclinic, P
(No. 2), a = 7.528(2) Å, b = 9.404(2) Å, c = 11.414(2) Å, = 75.363(3)°, = 86.668(4)°, = 89.683(4)°, and Z = 2. Crystal data for 2: Monoclinic, P21/c (No. 14), a = 8.242(2) Å, b = 14.870(2) Å, c = 13.060(2) Å, = 101.458(3)°, and Z = 4. Both compounds are highly unsaturated leading to extended aromatic conjugation. They show different intermolecular O–HO hydrogen bonds, via which 1 forms dimers, and 2 zig-zag polymeric chains. 相似文献
42.
Lavinia L. Ruta Ileana C. Farcasanu Mihaela Bacalum Mina Rileanu Arpad Mihai Rostas Constantin Daniliuc Mariana Carmen Chifiriuc Luminia Mruescu Marcela Popa Mihaela Badea Emilia Elena Iorgulescu Rodica Olar 《Molecules (Basel, Switzerland)》2021,26(22)
Novel complexes of type [Cu(N-N)(dmtp)2(OH2)](ClO4)2·dmtp ((1) N-N: 2,2′-bipyridine; (2) L: 1,10-phenantroline and dmtp: 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine) were designed in order to obtain biologically active compounds. Complexes were characterized as mononuclear species that crystallized in the space group P-1 of the triclinic system with a square pyramidal geometry around the copper (II). In addition to the antiproliferative effect on murine melanoma B16 cells, complex (1) exhibited low toxicity on normal BJ cells and did not affect membrane integrity. Complex (2) proved to be a more potent antimicrobial in comparison with (1), but both compounds were more active in comparison with dmtp—both against planktonic cells and biofilms. A stronger antimicrobial and antibiofilm effect was noticed against the Gram-positive strains, including methicillin-resistant Staphylococcus aureus (MRSA). Both electron paramagnetic resonance (EPR) and Saccharomyces cerevisiae studies indicated that the complexes were scavengers rather than reactive oxygen species promoters. Their DNA intercalating capacity was evidenced by modifications in both absorption and fluorescence spectra. Furthermore, both complexes exhibited nuclease-like activity, which increased in the presence of hydrogen peroxide. 相似文献
43.
M. Elisa Cristiana Grigorescu Ileana Vasiliu M. Bulinski V. Kuncser Dana Predoi G. Filoti Aurelia Meghea Nicoleta Iftimie Maria Giurginca C. Onose 《Optical and Quantum Electronics》2007,39(4-6):523-531
The paper deals with optical and electronic properties of the aluminophosphate glasses containing Fe–Mn and Fe–Cr ion pairs in different concentration. The influence of the mixed alkali ions over the electronic properties has been investigated. The optical behavior (optical transmission) of the glass samples has been studied by UV-VIS spectroscopy and the refractive index dependency on wavelength has been discussed. The transmission spectra show features specific for the doping transition ions (TM), revealing different oxidation states of iron (Fe2+/Fe3+), manganese (Mn2+/Mn3+) and chromium (Cr3+/Cr6+) in the vitreous network. Mössbauer spectroscopy offers information regarding the TM oxidation states, redox processes and the iron coordination symmetry in the vitreous network. In the case of Fe–Mn doped glasses, the percentage of Fe2+ is about 40% and a doubled iron content leads to an increasing of Fe2+ percentage up to 53%. The replacing of lithium ions by natrium ions (mixed alkali effect) provides an increasing of the Fe2+ percentage up to 56%. The occurrence of the tetrahedral or octahedral symmetry of Fe2+ ions bonded by O2? ions depends on the transition ion nature and Li+/Na+ ratio. Infrared absorption spectra of the pair transition ions-doped aluminophosphate glasses reveal optical phonons specific for the phosphate glass matrix. 相似文献
44.
45.
Ileana Nuţă Mihaela Badea Mariana Carmen Chifiriuc Coralia Bleotu Marcela Popa Constantin-Gabriel Daniliuc Rodica Olar 《应用有机金属化学》2020,34(9):e5807
New complexes of type [M(tbg)2]Cl2 [tbg = 1-(o-tolyl)biguanide; M = Ni(II), Pd(II), and Pt(II)] were synthesized and characterized to develop new biologically active compounds. The features of the complexes were assigned from microanalytical and thermal data. The NMR, FT-IR, and UV-Vis spectra were established by comparison with HtbgCl. All complexes exhibit a square-planar geometry resulting from the chelating behavior of tbg. The HtbgCl and [Ni(tbg)2]Cl2 complexes were fully characterized by single-crystal X-ray diffraction. The HtbgCl species crystallize in the monoclinic C2/c spatial group, while the Ni(II) complex adopts an orthorhombic Pna21 spatial group. The structure is stabilized by a complex hydrogen bonds network. The in vitro antimicrobial assays revealed improved antimicrobial activity for complexes in comparison with the ligand against both planktonic and biofilm embedded microbial cells. The most efficient compound, showing the largest spectrum of antimicrobial activity, including Gram-positive and Gram-negative bacteria, as well as fungal strains, in both planktonic and biofilm growth states was the Pd(II) complex, followed by the Pt(II) complex. The Pt(II) compound exhibited the most significant antiproliferative activity on the human cervical cancer SiHa cell line, inducing a cell cycle arrest in the G2/M phase. 相似文献
46.
Aiming at improving catalyst activity, ten ruthenium promoters have been investigated in carbenoid transfer from ethyl diazoacetate to styrene as a model substrate. Optimal selectivity in cyclopropanation has been attained with the new NHC–Ru complex 10 , as well as with the Fischer carbene 7 . The surprising non‐metathetical behavior of the Grubbs’ first‐generation catalyst in this multifaceted process is highlighted. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
47.
Elisabetta Schievano Ileana Menegazzo Ester Marotta Stefano Mammi 《Magnetic resonance in chemistry : MRC》2011,49(8):523-528
The chemistry of dyes and pigments is relevant to the textile industry, because of the importance to establish the best conditions for the finishing process and to understand the interactions among various compounds to yield the correct hue and nuances. For this reason, the molecular structure of a monoazo acid dye, C.I. Acid Red 131, was elucidated and characterized by homo‐ and hetero‐nuclear NMR, MS, IR and UV spectroscopy techniques. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
48.
Miron Teodor Căproiu Florea Dumitrascu Sergiu Shova Ileana Cornelia Chirită Alexandru Vasile Missir Dana-Mihaela Cioroianu 《Tetrahedron letters》2014
New S-thiocarbamates possessing a 10,11-dihydro-5H-dibenzo[a,d]cycloheptene moiety were obtained unexpectedly in the process of preparing new O-thiocarbamates starting from 5-dibenzosuberol (10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ol) and aroyl-isothiocyanates. These compounds were obtained via a benzylic Newman–Kwart rearrangement mechanism. The structures of the new thiocarbamates were confirmed by elemental analysis, IR, and NMR spectroscopy and by X-ray crystallography. 相似文献
49.
Cristina Ileana Covaliu Daniela Berger Cristian Matei Lucian Diamandescu Eugeniu Vasile Camelia Cristea Valentin Ionita Horia Iovu 《Journal of nanoparticle research》2011,13(11):6169-6180
This study reports a two-steps route for obtaining magnetic nanoparticles–polysaccharide hybrid materials consisting of Fe3O4, NiFe2O4 and CuFe2O4 nanoparticles synthesis by coprecipitation method in the presence of a soft template followed by coating of ferrite nanoparticles of 8–10-nm size range with polysaccharide type polymers—sodium alginate or chitosan. Magnetic oxide nanoparticles and the corresponding hybrid materials were characterized by X-ray diffraction (XRD), Mössbauer spectroscopy, atomic absorption spectroscopy (AAS), FTIR spectroscopy, scanning and transmission electron microscopy (SEM and TEM) and specific surface area measurements. The vibrating sample magnetometry confirms the superparamagnetic properties of the synthesized ferrites and hybrids. Using this route, the percent of magnetic nanoparticles retained in chitosan-based hybrid materials is nearly double in comparison with that of sodium alginate–based materials. The biological activity tests on Escherichia coli ATCC 25922, Pseudomonas aeroginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Candida scotti microorganisms show the non-toxic properties of prepared hybrid materials. 相似文献
50.