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Oxidative bromination and oxidation of organic substrates catalyzed by bis[2,2'‐hydroxyphenylbenzimidazole]Fe( III ) complex entrapped in zeolite‐Y cavity
Author(s) -
Eshwar Rao Shilpa,
Virupaiah Gayathri
Publication year - 2017
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5201
Subject(s) - catalysis , chemistry , zeolite , halogenation , cyclohexane , selectivity , bromine , ethylbenzene , organic synthesis , transition metal , organic chemistry , inorganic chemistry , photochemistry
BACKGROUND Zeolite encapsulated transition metal complexes have proven to be better catalysts for most organic transformations as they share advantages of both homogeneous and heterogeneous catalysts because the complex inside the zeolite cage can move within the cavity but at the same time cannot come out of it owing to its size. Hence, some reports claim application of these encapsulated complexes in various organic transformations. Introduction of bromine into aromatic compounds is an important fundamental reaction in organic chemistry. On the other hand, oxidations of saturated and unsaturated compounds also find application in the synthesis of fine chemicals. RESULTS The positions of peaks in the cyclic voltammogram of the encapsulated complex were unaltered, accompanied by an increase in current with scan rate, substantiating encapsulation of the complex within the cavity. This complex was catalytically active in the presence of H 2 O 2 towards the oxidation of cyclohexane and ethylbenzene. Its catalytic efficiency was examined in the oxidative bromination of organic substrates using KBr at room temperature, wherein high para‐selectivity was obtained. It displayed better conversion/selectivity than Fe(opbmzl) 2 NO 3 retaining its catalytic activity up to five consecutive runs. Plausible mechanisms involving hydro‐peroxo intermediate have been proposed. CONCLUSION Zeolite encapsulated bis[2,2'‐hydroxyphenylbenzimidazole]Fe( III ) complex behaved as a versatile catalyst for various organic transformations. © 2017 Society of Chemical Industry