Epoxidation of alkenes by an oxidovanadium(IV) tetradentate Schiff base complex as an efficient catalyst with tert-butyl hydroperoxide

Three novel paramagnetic metal complexes (MH 2 ID) of Ni 2+ , Cu 2+ and VO 2+ ions with 3-hydroxy-3,3'-biindoline-2,2'-dione (dihydroindolone, H 4 ID) were synthesized and characterized by different spectroscopic methods. The ligand (H 4 ID) was synthesized via homocoupling reaction of isatin in presence of phenylalanine in methanol. Complexation of low valent Ni 2+ , Cu 2+ ions and high valent VO 2+ ions with H 4 ID carried out in 1: 2 molar ratios. A comparison in the catalytic potential of paramagnetic complexes of low and high valent metal ion was explored in the oxidation processes of cis-cyclooctene, benzyl alcohol and thiophene by an aqueous H 2 O 2 , as a green terminal oxidant, in the presence and absence of acetonitrile, as an organic solvent, at 85°C. NiH 2 ID, CuH 2 ID and VOH 2 ID show good catalytic activity, i.e. good chemoand regioselectivity. VOH 2 ID has the highest catalytic potential compared to both Ni 2+and Cu 2+ -species in the same homogenous aerobic atmosphere.Catalytic oxidation of other alkenes and alcohols was also studied using NiH 2 ID, CuH 2 ID or VOH 2 ID as a pre-catalyst by an aqueous H 2 O 2 . A mechanistic pathway for those oxidation processes was proposed.

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Catalytic activity of nickel(II), copper(II) and oxovanadium(II)‐dihydroindolone complexes towards homogeneous oxidation reactions

Adam

2018

“…A total (10 mmol) of 2-hydroxyacetophenone (HAP; 1.20 ml), [21] 2-hydroxypropiophenone (HPP; 1.37 ml), benzoylacetone (BA; 1.50 ml), acetylacetone (AA; 1.00 ml) or ethylacetoacetate (EAA; 1.30 ml) was added dropwise to HNP-OPD (10 mmol, 2.55 g) dissolved in 30 ml of RS with continuous stirring to synthesis unsymmetric bis Schiff base ligands ( Figure 2). The solution was refluxed for for 1 h. The mixture was cooled and filtered off, washed with RS then dried and stored in a desiccator over silica gel along with calcium chloride.…”

Section: Synthesis Of Unsymmetric Bis Schiff Basesmentioning

confidence: 99%

Oxotitanium(IV) complexes of some bis‐unsymmetric Schiff bases: Synthesis, structural elucidation and biomedical applications

Uddin

Siddique

Mase

et al. 2019

A number of oxotitanium(IV) complexes of the type TiOL with bisunsymmetric dibasic tetradentate Schiff base (LH 2 ) containing ONNO donor atoms have been synthesized. Mono-Schiff base (OPD-HNP) was prepared by the condensation of 1:3 molar ratio of 2-hydroxy-1-naphthaldehyde (HNP)with o-phenylenediamine (OPD). Dibasic unsymmetric tetradentate diamine Schiff bases were prepared by the reaction of OPD-HNP with 2-hydroxyacetophenone, 2-hydroxypropeophenone, benzoylacetone, acetylacetone and ethylacetoacetate. Further, titanylacetylacetonate was reacted with these ligands to obtain their metal complexes. On the basis of analytical and physiochemical data, the formation of complexes as TiOL was suggested having square pyramidal geometry. Quantum mechanical approach also confirmed this geometry. The assessment of the synthesized ligands and their complexes showed that some behave as good inhibitors of mycelial growth against selected phytopathogic fungi but weak inhibitors against some selected bacteria. A few of them also showed antioxidant properties.

“…In recent years, different types of vanadium coordination compounds with Schiff base ligands were synthesized and used as homogeneous and heterogeneous catalysts in the epoxidation reactions . Moreover, to modify the stabilization and recycling ability of the homogeneous catalysis systems, they have been immobilized onto the solid supports.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a new schiff base oxovanadium complex with melamine and 2‐hydroxynaphtaldehyde on modified magnetic nanoparticles as catalyst for allyl alcohols and olefins epoxidation

Farzaneh

Asgharpour

2019

A new magnetically recoverable nanocatalyst designated as Fe3O4@SiO2@PTMS@Mel‐Naph‐VOcomplex was synthesize by covalent binding of a Schiff base ligand derived from melamine and 2‐hydroxy1naphtaldehyde on the surface of silica coated iron oxide magnetic nanoparticles followed by complexation with VO (acac)2. Characterization of the prepared nanocatalyst was accomplished with FT‐IR, XRD, SEM, HRTEM, VSM and atomic absorption techniques. It was found that the epoxidation of geraniol, trans‐2‐hexen‐1‐ol, 1‐octen‐3‐ol, norbornene, and cyclooctene is highly selective, affording quantitative yields of the corresponding epoxides with tert‐butyl hydroperoxide (TBHP) using Fe3O4@SiO2@Mel‐Naph‐VOcomplex as catalyst. High reaction yields, short reaction times, simple experimental and work up procedure, catalyst stability and excellent reusability even after five‐cycles of usage in the case of geraniol are some advantages of this research.