- Influence of substituents on the structure of Schiff bases Cu(II) complexes
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The relationship between molecular conformation and substituent effects of salicylaldehyde Schiff-base Cu(II) complexes was explored. For this study, eight samples of the complexes Cu(Sal-X)2 (X = OMe, Me, H, F, Cl, Br, CF3 and CN) w
- Xiao, Yan,Cao, Chenzhong
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- Effect of substituents on the UV spectra of supermolecular system: Silver nanoparticles with bi-aryl Schiff bases containing hydroxyl
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Effect of substituents on the ultraviolet (UV) spectra of supermolecular system involving silver nanoparticles (AgNPs) and Schiff bases was investigated. AgNPs and 49 samples of model compounds (MC), bi-aryl Schiff bases containing hydroxyl (XBAY, involving 4-OHArCH?NArY, 2-OHArCH?NArY, XArCH?NAr-4′-OH, and XArCH?NAr-2′-OH), were synthesized. The size of AgNPs was characterized by transmission electron microscopy (TEM), and the UV absorption spectra of AgNPs, XBAYs, and MC-AgNPs mixed solutions were measured, respectively. The results show that (1) the size of AgNPs is larger in MC-AgNPs solutions than that in AgNPs solution due to the distribution of MC molecules on the surface of AgNPs; (2) the UV absorption wavelength of XBAYs changes in the action of AgNPs and their wavelength shift exists limitation between XBAY and MC-AgNPs solutions; and (3) the wavelength shift limit of MC-AgNPs (λWSL) is influenced by the substituents X and Y and the position of hydroxyl OH. The wavenumber ΔνWSL of λWSL can be quantified by employing the excited-state substituent constant σexCC and Hammett constant σ of substituents X and Y. Comparing with the 4-OH, the 4′-OH makes the ΔνWSL a red shift, whereas the 2′-OH, comparing with the 2-OH, makes the ΔνWSL a blue shift.
- Cao, Chao-Tun,Cheng, Shimao,Zhang, Jingyuan,Cao, Chenzhong
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- AIPE-active platinum(ii) complexes with tunable photophysical properties and their application in constructing thermosensitive probes used for intracellular temperature imaging
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Aggregation-induced phosphorescent emission (AIPE) luminogens based on phosphorescent transition metal complexes have many application advantages in bioimaging compared with fluorescent organic dyes because of their long excitation lifetime and reduced ph
- Lin, Shengheng,Pan, Honghao,Li, Lin,Liao, Rui,Yu, Shengzhen,Zhao, Qiang,Sun, Huibin,Huang, Wei
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supporting information
p. 7893 - 7899
(2019/07/10)
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- Impact of various lipophilic substituents on ruthenium(II), rhodium(III) and iridium(III) salicylaldimine-based complexes: synthesis, in vitro cytotoxicity studies and DNA interactions
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Abstract: A series of bidentate salicylaldimine ligands was prepared and reacted with either [RuCl(μ-Cl)(p-cymene)]2, [RhCl(μ-Cl)(Cp*)]2 or [IrCl(μ-Cl)(Cp*)]2. All of the compounds were characterised using an array of spectroscopic and analytical techniques, namely, nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy and mass spectrometry. Single crystal X-ray diffraction (XRD) was used to confirm the bidentate coordination mode of the salicylaldimine ligand to the metal centre. The platinum group metal (PGM) complexes were screened against the MCF7 breast cancer cell line. The ruthenium and iridium salicylaldimine complexes showed comparable or greater cytotoxicity than cisplatin against the MCF7 cancer cells, as well as greater cytotoxicity than their rhodium counterparts. Three of the salicylaldimine complexes showed potent activity in the range 18–21?μM. Two of these complexes had a greater affinity for cancerous cells than for CHO non-cancerous cells (SI > 4). Preliminary mechanistic studies suggest that the ruthenium complexes undergo solvation prior to 5′-GMP binding, whereas the iridium complexes were inert to the solvation process. Graphical abstract: [Figure not available: see fulltext.].
- Cassells, Irwin,Stringer, Tameryn,Hutton, Alan T.,Prince, Sharon,Smith, Gregory S.
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p. 763 - 774
(2018/06/06)
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- Halide substituted Schiff-bases: Different activities in methyltrioxorhenium(VII) catalyzed epoxidation via different substitution patterns
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This report shows the influence of halide substituted Schiff-bases as ligands of methyltrioxorhenium (MTO) in epoxidation catalysis. Therefore, selected Schiff-bases were prepared by the reaction of hydroxy-benzaldehydes and aniline derivates. These differently substituted Schiff-bases were tested as MTO-ligands in cyclooctene-and 1-octene-epoxidation. Although no great disparities among the substitution patterns have been found, some conclusions can be drawn. Flourines are inferior to chlorines or bromines as substituents. Halides in ortho-position lead to higher activities than in para-or meta-position. The balance between electron donating and withdrawing influences at the Schiff-base plays a prominent role in their utility as ligand to MTO in epoxidation catalysis.
- Altmann, Philipp,Cokoja, Mirza,Kühn, Fritz E.
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experimental part
p. 51 - 55
(2012/03/11)
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- Methyltrioxorhenium-catalyzed oxidation of pseudocumene for vitamin e synthesis: A study of solvent and ligand effects
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Vitamin E is an essential food component of major economical relevance with important antioxidant properties and biological activity. The oxidation of pseudocumene to trimethyl-1,4-benzoquinone would be a key transformation in an alternative industrial production of α-tocopherol that is important for the antioxidant activity of vitamin E. The methyltrioxorhenium (MTO)-catalyzed oxidation of pseudocumene has been revisited to offer a more environmentally friendly, economically beneficial and milder approach to this important industrial product. It has been observed that by choosing the solvent and Lewis base additives (as ligands of MTO), both yield and chemoselectivity are considerably improved, allowing milder reaction conditions compared to previously reported protocols.
- Carril, Monica,Altmann, Philipp,Drees, Markus,Bonrath, Werner,Netscher, Thomas,Schuetz, Jan,Kuehn, Fritz E.
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experimental part
p. 55 - 67
(2011/11/30)
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