Synthesis and properties of water-soluble fluorescent 2-borylazobenzenes bearing ionic functional groups
摘要:
Water-soluble fluorescent azobenzenes have been synthesized by quaternization of 2-[bis(pentafluorophenyl) boryl] azobenzenes bearing dimethylamino groups with iodomethane or propanesultone. The 2-borylazobenzenes both dissolve and fluoresce in water. The double introduction of ionic moieties provides the azobenzenes with higher water solubility. Dynamic light scattering and scanning electron microscopy measurements indicate that the 2-borylazobenzenes aggregate in water. They are expected to be applied in aqueous environments. (C) 2011 Elsevier B.V. All rights reserved.
lengths than those in the corresponding adducts (C6F5)3B·Do. Both the free Lewis acid [1][Al(O(tBuF))4] and its triflate adduct (1)OTf have successfully been employed as catalysts for the [4+2] cycloaddition reaction between 2,5-dimethyl-1,4-benzoquinone and cyclopentadiene. Moreover, we have shown that chiral phosphoniumboranes are accessible by replacement of one tBu group in [1]+ by a Me substituent
Synthesis of Cyclopentadienyl-, Indenyl-, and Fluorenylbis(pentafluorophenyl)boranes as Ligands in Titanium and Zirconium Half-Sandwich Complexes. The Crystal Structures of C<sub>13</sub>H<sub>9</sub>B(C<sub>6</sub>F<sub>5</sub>)<sub>2</sub>·<i>t</i>-BuNH<sub>2</sub>, C<sub>13</sub>H<sub>8</sub>SiMe<sub>3</sub>B(C<sub>6</sub>F<sub>5</sub>)<sub>2</sub>, and {η<sup>5</sup>-C<sub>5</sub>H<sub>4</sub>B(C<sub>6</sub>F<sub>5</sub>)<sub>2</sub>}TiCl<sub>3</sub>
作者:Robbert Duchateau、Simon J. Lancaster、Mark Thornton-Pett、Manfred Bochmann
DOI:10.1021/om970433j
日期:1997.11.1
Bis(pentafluorophenyl)boron fluoride (C6F5)2BF·OEt2 (1), readily accessible from BF3·OEt2 and 2 equiv of C6F5MgBr, reacts with fluorenyllithium to give (Flu)B(C6F5)2 (4), while the reaction with indenyllithium leads to the regioisomers 1- and 2-IndB(C6F5)2 5 and 6, which are separated by fractional crystallization. 4 and 5 form crystalline adducts with tert-butylamine. The trimethylsilyl derivatives
易于从BF 3 ·OEt 2和2当量的C 6 F 5 MgBr中获得的双(五氟苯基)氟化硼(C 6 F 5)2 BF·OEt 2(1)与芴基锂反应生成(Flu)B(C 6 F 5)2(4),而与茚基锂的反应导致区域异构体1-和2-IndB(C 6 F 5)2 5和6,通过分步结晶分离。4和5 与叔丁胺形成结晶加合物。类似地制备三甲基甲硅烷基衍生物Flu(SiMe 3)B(C 6 F 5)2(9)和Ind(SiMe 3)B(C 6 F 5)2(10)。加热(C 6 F 5)2 BF·OEt 2导致醚裂解并形成(C 6 F 5)2 BOEt。Zr(NMe 2)4处理5和6在室温下得到茚并锆酰胺基半三明治复合物;然而,该反应伴随有一个硼-C 6 F 5取代基被NMe 2意外交换,从而形成1-和2- C 9 H 6 B(C 6 F 5)(NMe 2)} Zr(NMe 2)3。与SiClMe 3反应得到三氯化物1-和2-
Intensely Fluorescent Azobenzenes: Synthesis, Crystal Structures, Effects of Substituents, and Application to Fluorescent Vital Stain
process and from DFT and TD‐DFT calculations. An electron‐donating group at the 4′‐position was found to be important for an intense emission. Application of fluorescentazobenzenes as a fluorescentvitalstain for the visualization of living tissues was also investigated by microinjection into Xenopus embryos, suggesting these compounds are nontoxic towards embryos.
2,2′-Bis[bis(pentafluorophenyl)boryl]azobenzenes were synthesized. X-ray crystallographic analysis exhibits a planar core structure of the azobenzene moiety, double intramolecular N–Bcoordination, and two tetracoordinate boron atoms. The 2,2′-diborylazobenzenes show fluorescence emission with orange and red colors upon irradiation. The doubleN–Bcoordination causes redshifts in both the absorption
reversible one-electron oxidation processes, suggesting stable redox triads involving anionic aminoxide, neutral nitroxide-radical, and cationic oxoammonium ligands. Cationic boron complexes of the nitroxide radical ligands were obtained via chemical oxidation of the aminoxide complexes and structurally characterised. The cationic nitroxide-radical complexes exhibited strong absorptions at approximately