Selective oxidation of benzyl alcohols by silica‐supported heterogeneous catalyst containing dioxidotungsten(VI) core

Abstract

A dioxidotungsten(VI) complex, [WO 2 L(CH 3 OH)]Á0.5(CH 3 OH) (1), was prepared by the reaction of WCl 6 and tridentate ONO-donor Schiff base ligand (H 2 L) that was obtained from the reaction of 2-hydroxy-1-naphthaldehyde with 4-aminobenzoic hydrazide. Both H 2 L and 1 were characterized by various analyses including nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and UV-Vis spectroscopy, and elemental analysis. Single crystal X-ray analysis was used to determine the crystal structure of the complex, which revealed that there is a free -NH 2 group in its structure.

Investigation of the substituent effects on the oxidation of styrene derivatives by silica‐supported heterogeneous oxidovanadium(V) coordination compound

“…[18] Preparing appropriate coordination compounds containing suitable functional groups to prepare heterogeneous catalysts is one of the challenges in this field. [19] Structural characterization of coordination compounds in the heterogeneous systems is the next challenge in this area. [20] Professional designing of ligands with appropriate functional groups and determining the structure of coordination compounds by single crystal X-ray diffraction studies before heterogenization process are two acceptable methods to overcome to these challenges and provide heterogeneous catalysts with greater structural accuracy.…”

Preparative and Catalytic Properties of MoVI Mononuclear and Metallosupramolecular Coordination Assemblies Bearing Hydrazonato Ligands

“…Singlets at 8.75-8.63 ppm and 3.77-3.73 ppm were assigned to the CH=N and OCH 3 groups, respectively. The aromatic moieties gave signals in the range of 9.19-6.65 ppm [45]. In the 13 Due to the donor properties of the solvent DMSO-d 6 , the metallosupramolecular nature of complexes 1-4 and the presence of ancillary ligand in the mononuclear complexes 1a-4a were disrupted, and complexes [(MoO 2 ) 2 (L 1-4 )(DMSO)] appeared instead.…”

Titania supported dioxidotungsten(vi) complex as bio-mimic for the type II copper-containing oxidase enzyme phenoxazinone synthase

“…29 This enzyme, with the ability to cure germ cell cancers, Wilm's tumour, Ewing's sarcoma, Kaposi's sarcoma, gestational choriocarcinoma, and rhabdomyosarcoma, 30 catalyses the coupling of substituted o -aminophenol to phenoxazinone chromophore in the synthesis of actinomycin D. 31 Our present study describes the synthesis of homogeneous dioxidotungsten( vi ) complex of deferasirox {4-[3,5-bis(2-hydroxyphenyl)-1 H -1,2,4-triazol-1-yl]benzoic acid, H 3 hptb, I }, its heterogeneous analogue immobilized on amine-functionalized titania and their application in functional mimicking the phenoxazinone synthase (PHS) enzyme. Though SiO 2 , Fe 3 O 4 and other inorganic materials are available for the immobilization of metal complexes, 32–35 we recently observed that TiO 2 has worked as an excellent support in immobilizing molybdenum complexes. 26,36 Further, such TiO 2 -supported metal complexes based catalysts are recyclable and re-usable.…”