16265-11-5Relevant articles and documents
Some contribution to W(VI)-peroxo-chemistry: Synthesis, spectroscopic characterization, reactivity and DFT studies
Bhattacharjee, M.,Boruah, S. R.,Chowdhury, S.,Das, N.,Dutta Purkayastha, R. N.
, (2022/01/14)
Synthesis of white microcrystalline oxodiperoxotungstate(VI) complexes, K[WO(O2)2(L)(H2O)]·H2O, (L ?= ?salicylate, 5-chlorosalicylate, 4-hydroxybenzoate) have been achieved from reaction of Na2WO4·2H2O with 30% H2O2 and the respective hetero-ligands at pH Ca. 7–7.5 in aqueous medium. The newly synthesized compounds were comprehensively characterized by elemental analyses, spectral studies, room temperature magnetic moment measurements and mass spectrometric studies. Infrared spectra suggest that, peroxo groups are bonded to the WO+4 center in a triangular bidentate (C2v) fashion and the hetero-ligands benzene-core hydroxycarboxylic acids viz. salicylic acid, 5-chlorosalicylic acid, 4-hydroxybenzoic acid in anoinic form are coordinated in monodentate manner. Compounds are fairly stable in aqueous solution for sufficient period of time. The results of mass spectrometric analysis lend support to the molecular composition of the complexes ascertained on the basis of elemental analyses and spectroscopic studies. Compound potassium(aquo)(5-chlorosalicylato)oxodiperoxotungstate(VI)monohydrate, K[WO(O2)2(5-chlorosalicylate)(H2O)]·H2O, act as an oxidant of bromide ion in aqueous phase bromination of chosen organic substrates to their corresponding bromo organics. Density Functional Theory (TD-DFT) calculations were performed on the synthesized complexes substantiated the experimentally obtained results. The TD-DFT optimized structures are in excellent agreement with the results of elemental analyses, spectral as well as mass spectrometric data.
Peroxo–tungstate(VI) complexes: syntheses, characterization, reactivity, and DFT studies
Das, Nandita,Chowdhury, Shubhamoy,Purkayastha, Ranendra N. Dutta
, p. 1255 - 1266 (2019/07/04)
Abstract: Three new oxodiperoxo–tungsten(VI) complexes containing benzene core carboxylic acids, viz., benzoic acid, 2-chlorobenzoic acid, and 3-aminobenzoic acid as co-ligands have been synthesized from reaction of Na2WO6H4, 30% H2O2 and the corresponding co-ligands in aqueous medium. The compounds have been comprehensively characterized by elemental analyses, FT-IR, 1H NMR, UV–Vis spectral studies as well as by mass spectrometric and TGA analyses. The infrared spectra suggest occurrence of terminally bonded W=O as well as triangular bidentate peroxo groups (C2v) and monodentate carboxylate group bound to the WO4+ center. The mass spectra of the compounds are in good agreement with proposed molecular formulations. Thermogravimetric analyses indicate the existence of both lattice and coordinated water molecules in the complexes. Density functional theory (DFT) calculations were used to compute the frequencies of relevant vibrational modes, electronic properties and also to investigate structure of the compounds. Compound potassium(aquo)(2-chlorobenzoato)oxodiperoxo–tungstate(VI)dihydrate acts as an oxidant for bromide ion in aqueous phase bromination of chosen organic substrates to their corresponding bromo-organics. Graphical abstract: [Figure not available: see fulltext.]
Highly regioselective C-5 alkynylation of imidazoles by one-pot sequential bromination and Sonogashira cross coupling
Bellina, Fabio,Lessi, Marco,Marianetti, Giulia,Panattoni, Alessandro
supporting information, p. 3855 - 3857 (2015/06/08)
A variety of 2-substituted 5-alkynyl-1H-imidazoles were easily prepared by a one-pot sequential procedure involving a highly regioselective electrophilic C-5 bromination of 1,2-dimethyl-1H-imidazole, 2-chloro-1-methyl-1H-imidazole, and 2-aryl-1-methyl-1H-imidazoles, followed by an efficient palladium/copper co-catalyzed Sonogashira-type alkynylation.