Synthesis, characterization and catalytic epoxidation of cyclohexene using dimeric cis-dioxomolybdenum(VI) bis-bidentate Schiff base complexes supported on single wall carbon nanotubes

Abstract

Three dimeric cis-dioxomolybdenum(VI) complexes of bis-bidentate Schiff base derivatives containing aromatic nitrogen-nitrogen linkers (4,4 0 -diaminodiphenylmethane; 4,4 0 -diaminodiphenylether; 4,4 0 -diaminodiphenylsulfone) with 2-hydroxy-1-naphthaldehyde have been synthesised and characterized by physico-chemical and spectroscopic methods. The catalytic activities of the complexes with respect to alkene epoxidation using tertbutylhydroperoxide (TBHP) as oxidant have been studied. The addition of single wall nanotubes can enhance the catalytic activities of the Mo complexes and the selectivity of epoxide formation.

Green epoxidation of 1-hexene: O2 utilizing cis-MoO2 Schiff base complex

“…Mo(VI) complexes are well known as potent catalysts for the epoxidation of alkenes by hydroperoxides such as tert-butylhydroperoxide. Several authors [20][21][22][23] have reported on the oxotransfer activity of several dioxomolybdenum complexes in different Schiff base environments. We have been interested in five-coordinate octahedral cis-MoO 2 complexes with non-symmetrical Schiff bases having mixed sets of donor atoms in which the sixth coordination site is occupied by a solvent molecule.…”

Synthesis, characterization and catalytic oxidation of para-xylene by a manganese(iii) Schiff base complex on functionalized multi-wall carbon nanotubes (MWNTs)

“…During the last decade, studies on the isolation, characterization and catalytic activity of transition metal complexes covalently grafted on various carbon nanotubes (CNTs) received considerable attention because of their specific catalytic applications when compared to homogeneous complexes. [1][2][3][4][5][6][7][8][9][10] The heterogenization process provides a rigid framework to the metal complex outside the CNTs due to spatial restrictions, and covalent bonding. It also facilitates the reactions to occur under mild experimental conditions.…”

Grafting of copper(II) Schiff base complex on functionalized multi-wall carbon nanotubes: Synthesis, characterization and catalytic aziridination of olefins

“…During the last decade, studies on the isolation, characterization and catalytic activity of transition metal complexes covalently grafted on various CNTs received considerable attention because of their specific catalytic applications when compared to homogeneous complexes [24][25][26][27][28][29][30]. The heterogenization process provides a rigid framework to the metal complex outside the CNTs due to spatial restrictions, and covalent bonding.…”

“…Due to these features, the transition metal complexes grafted on various CNTs resemble, to a certain extent, to the enzymes where the catalytic active centers might be a transition metal ion and the protein sheath provides the stability and steric constraints. Inorganic complexes supported in such constrained environments can therefore be termed as zeozymes [24][25][26][27][28][29][30]. In the present work, we have reported the catalytic activity in the aziridination of alkenes using PhI = NTs as nitrogen source at room temperature, of [Cu((OH) 2 -salophen)] [(OH) 2 -salophen] = (N,N´-bis(4-hydroxysalicylidene)phenylene-1,2-diamine) anchored on a chemically oxidized multi-wall carbon nanotubes (MWNTs).…”

“…This band is shifted to a longer wave length (18 nm) along with increasing in its intensity. This shift may be attributed to the donation of the lone pairs of the nitrogen atoms of the Schiff base to the metal ion (N→M)[22][23][24][25][26][27][28][29][30][31][32]. The spectra of copper(II) complex show two bands in the visible region at about 565 and 426 nm and they are assigned to 2 B 1g → 2 A 1g and 2 B 1g → 2 E g transitions, respectively.…”