- Synthesis and photophysical properties of ditrifluoroacetoxyboron complexes with curcumin analogues
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A new class of ditrifluoroacetoxyboron complexes were designed and synthesized by chelation reaction of curcumins with boron trifluoroacetate. Their photophysical behaviors were studied in different solvents, powder state and PMMA polymer films. The results indicated that these complexes revealed a green to yellow emission at 486–595 nm in solution or PMMA films and an orange to red emission at 598–710 nm in powder state. Especially, complex 2c displayed the strongest emission intensity, the highest quantum yield in solution and the longest fluorescence lifetime in powder state in these complexes. In addtion, the emission bathochromic shifts of these complexes as a function of the solvent polarity parameter ET(30) were investigated by Lippert–Mataga approximation. It was observed that these complexes exhibited the higher values of the dipole moment difference (Δμ) between the ground and excited states, which implied an intense intramolecular charge transfer characteristics and a noticeable emission solvatochromic effect.
- Cai, Lian,Du, Hengyi,Lyu, Heng,Wang, Dan,Wang, Dunjia
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- Synthesis and mutual transformations of nitronium tetrakis(nitrooxy)- And tetrakis(2,2,2-trifluoroacetoxy)borates
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Nitronium borates of NO2[B(OX)4] type with X = CF3CO and NO2 as ligands were synthesized, and their structures were determined by powder X-ray diffraction. Crystalline NO2[B(ONO2)4] is relatively stable at room temperature and undergoes transformation to B2O3 upon heating. The [B(CF3COO)4]- anion was obtained for the first time and characterized as a structural fragment of a solid compound. The possibility of reversible modification of the complex anion by replacement of the nitrate or trifluoroacetate ligand was demonstrated for the first time by the mutual transformations of NO2[B(ONO2)4] and NO2[B(CF3COO)4].
- Zelenov, Victor P.,Gorshkov, Evgeny Yu.,Zavaruev, Mikhail V.,Dmitrienko, Artem O.,Troyan, Ivan A.,Pivkina, Alla N.,Khakimov, Dmitry V.,Pavlikov, Alexander V.
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p. 13944 - 13951
(2020/09/03)
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- Boron carboxylate catalysis of homoallylboration
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Boron tris(trifluoroacetate) is identified as the first effective catalyst for the homoallyl- and homocrotylboration of aldehydes by cyclopropylcarbinylboronates. NMR spectroscopic studies and theoretical calculations of key intermediates and transition states both suggest that a ligand-exchange mechanism, akin to our previously reported PhBCl 2-promoted homoallylations, is operative. Our experimental and theoretical results also suggest that the catalytic activity of boron tris(trifluoroacetate) might originate from more facile catalytic turnover of the trifluoroacetate ligands (in agreement with DFT calculations) or from a lower propensity for formation of off-pathway reservoir intermediates (as observed by 1H NMR). This work shows that carboxylates are viable catalytic ligands for homoallyl- and homocrotylations of carbonyl compounds and opens the door to the development of catalytic asymmetric versions of this transformation.
- Dugas, Gabrielle J.,Lam, Yu-Hong,Houk,Krauss, Isaac J.
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p. 4277 - 4284
(2014/06/09)
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- Synthesis and spectroscopic properties of porphyrin derivatives of C60
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Chemical synthesis of two C60 fullerene derivatives: with porphyrin (C 60-H2P) and of the iodide salt of Zn porphyrin (C 60-H2P)+I- is described. Both compounds are soluble in several organic solvents, with a larger solubility observed for C60-H2P. Thin films obtained by solution drawing or by spinning techniques from C60-H2P solution in organic solvents or dissolved in a polymer matrix show a peculiar granular structure with regular submicron size particles. Their size of is a little smaller in polymer matrix. The solution UV-Vis absorption spectra exhibit typical bands which can be attributed to porphyrin and to the fullerene. A solvatochromic effect is observed in C 60-H2P which shows a nonzero first hyperpolarizability , most likely due to the charge transfer between fullerene and porphyrin. Copyright Taylor & Francis Group, LLC.
- Prato,Soombar,Vazquez,Niziol,Gondek,Rau,Kajzar
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experimental part
p. 253 - 264
(2011/08/21)
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- Preparation of phenylalkyl ethers and phenyl esters from benzenediazonium tetrafluoroborate with alkoxytrimethylsilanes and trimethylsilyl esters
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Sonication assisted reaction of benzenediazonium tetrafluoroborate with alkoxytrimethylsilanes and trimethylsilyl esters gives phenylalkyl ethers and phenyl esters, respectively, with trialkyl(aryl) borates as byproducts. The scope of the reaction, experimental conditions and proposed mechanism are discussed.
- Olah,Wu
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p. 204 - 206
(2007/10/02)
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