- COMPLEX FORMATION OF CYCLOMALTO-OCTAOSE WITH TETRABROMOPHENOLPHTHALEIN AND SOME RELATED COMPOUNDS
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The interactions of cyclomalto-octaose (γ-cyclodextrin) with some phthalein-type acid-base indicators have been investigated photometrically.Bromine substituents enhance the formation of complexes and tetrabromophenolphthalein forms the most stable complex (K 6.0 x 1E3).This stability and other phenomena suggest that the host and guest are involved in a three-site interaction.
- Barcza, Lajos,Buvari-Barcza, Agnes
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- Crystal structure and catalytic properties of a vanadium complex cis-[VO2(Him-py)(im-py)]2·3H2O
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The coordination behavior of Him-py (2-(1H-imidazol-2-yl)pyridine) toward vanadium has been explored. The six-coordinate complex, cis-[VO2(Him-py)(im-py)]2·3H2O (1), was synthesized by the coordination reaction of NH4VO3 and Him-py in the aqueous methanol solution, which was characterized by single-crystal X-ray technology. It belongs to the monoclinic space group P21/n with a = 8.0756(6), b = 19.3531(15), c = 11.4433(8), β = 106.905(2), V = 1711.2(2), and Z = 2. The crystal structure shows that the six-coordinate vanadium is bonded to two cis-oxido ligands and two bidentate ligands, Him-py and im-py. Interestingly, when crystals of 1 were immersed in H2O2, a peroxovanadium compound, (H2im-py)[OV(O2)2(Him-py)] (2), was obtained, which crystallizes in the orthorhombic space group Fdd2 with a = 22.600(2), b = 22.7259(13), c = 18.0146(11), V = 9252.4(12), and Z = 16, and consists of a seven-coordinate peroxovanadate(V) ion, one Him-py and one H2im-py ligand. Moreover, we also studied the catalytic activity of 1 in the oxidative bromination of phenol/aniline-like compounds towards mimicking bromoperoxidase reactivity.
- Sun, Meng,Zhang, Shaowei,Zhang, Jie,Xia, Wen,Chen, Jialiang,Yu, Xianyong
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p. 1899 - 1909
(2019/06/04)
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- 1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octane tribromide as a regenerable and useful reagent for bromination of phenols under mild conditions
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1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octane tribromide has been examined over several phenolic compounds under mild conditions. The reaction gives brominated phenols in good to excellent yields. Straightforward work-up of the reaction yields pure products in several cases.
- Hajipour, Abdol R.,Pourmousavi, Seied A.,Ruoho, Arnold E.
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p. 796 - 800
(2007/10/03)
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- A controlled and selective bromination of phenols by benzyltriphenylphosphonium tribromide
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Reactions of phenols with benzyltriphenylphosphonium tribromide in dichloromethane-methanol mixture (2:1) gave mono, di and tri brominated phenols at room temperature with high selectivity and good yields.
- Hajipour, Abdol Reza,Mallakpour, Shadpour E.,Imanieh, Hossein,Pourmousavi, Seied A.
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p. 272 - 275
(2007/10/03)
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