Dioxo and oxo-peroxo molybdenum(VI) complexes bearing salicylidene 2-picoloyl hydrazone: Structures and catalytic performances

Bagherzadeh, Mojtaba; Zare, Maryam; Amani, Vahid; Ellern, Arkady; Woo, L. Keith

doi:10.1016/j.poly.2013.01.054

Cited by 63 publications

(36 citation statements)

References 32 publications

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“…By considering of mechanism in Scheme 2, it seems that the competition between methanol and acetonitrile as a coordinator solvent and (CH 3 ) 3 COO − in coordination to Mo(VI) causes a marked decrease in the catalyst activity. [37] Apparently, the lower reflux reaction temperature is the reason for the lowest epoxidation conversion in CH 2 Cl 2 (37%). For optimization of reaction temperature, catalytic epoxidation of cyclooctene was carried out in chloroform with TBHP at four temperatures (30, 40, 50, 60°C).…”

Section: Epoxidation Of Olefins Catalysed Bymentioning

confidence: 97%

Excellent alkene epoxidation catalytic activity of macrocyclic‐based complex of dioxo‐Mo(VI) on supermagnetic separable nanocatalyst

Payami

Bezaatpour

Eskandari

2017

Applied Organom Chemis

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A phenoxybutane-based Schiff base complex of cis-dioxo-Mo(VI) was supported on paramagnetic nanoparticles and characterized using powder Xray diffraction, infrared, diffuse reflectance and atomic absorption spectroscopies, scanning and transmission electron microscopies and vibrating sample magnetometry. The separable nanocatalyst was tested for the selective epoxidation of cyclohexene, cyclooctene, styrene, indene, α-pinene, 1-octene, 1-heptene, 1-dodecene and trans-stilbene using tert-butyl hydroperoxide (80% in di-tert-butyl peroxide-water, 3:2) as oxidant in chloroform. The catalyst was efficient for oxidation of cyclooctene with 100% selectivity for epoxidation with 98% conversion in 10 min. We were able to separate magnetically the nanocatalyst using an external magnetic field and used the catalyst at least six successive times without significant decrease in conversion.The turnover frequency of the catalyst was remarkable (2556 h −1 for cyclooctene). The proposed nanomagnetic catalyst has advantages in terms of catalytic activity, selectivity, catalytic reaction time and reusability by easy separation.

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Section: Epoxidation Of Olefins Catalysed Bymentioning

confidence: 97%

Excellent alkene epoxidation catalytic activity of macrocyclic‐based complex of dioxo‐Mo(VI) on supermagnetic separable nanocatalyst

Payami

Bezaatpour

Eskandari

2017

Applied Organom Chemis

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“…The performing results for the activity and stability of these easily prepared current complexes during the oxidation reactions [cf. Scheme 2], leading to low/good conversion at reasonably low reaction Scheme 2 The tentative mechanism for oxidation of benzyl alcohol catalyzed by the Cu(II)-Schiff base complexes times with H 2 O 2 , along with good chemoselectivity conversion are strong advantages of the present Cu 2+ complexes as oxidation catalysts [66].…”

Section: Effect Of Catalyst Amountmentioning

confidence: 99%

“…Scheme 1). The structural features of the characteristic Cu 2+ complex unit with various-dentate Schiff base ligands[66,67] are illustrated in the suggested mechanism. Cunbisnph and Cunpisnph complexes (as tetradentate Schiff base units) have an open coordination site for the oxidant activation occupied by a water molecule or an acetate ion (cf.…”

mentioning

confidence: 99%

Some New Nano-sized Mononuclear Cu(II) Schiff Base Complexes: Design, Characterization, Molecular Modeling and Catalytic Potentials in Benzyl Alcohol Oxidation

et al. 2016

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In the present contribution, some novel Cu(II) complexes were synthesized from tri-and tetradentate imine ligands. All the prepared compounds were elucidated by different physicochemical methods. Density Functional Theory calculations were carried out to explain the equilibrium geometry of the bsisnph and npisnph ligands and their Cu(II) complexes. Interaction of the synthesized ligands with Cu(II) affords nano-sized particles via TEM. The catalytic potentials of the prepared complexes has been tested within the oxidation of benzyl alcohol using an environmental friendly terminal oxidant, i.e. H 2 O 2 . The effect of various parameters, e.g. solvents, temperature and amount of catalyst was investigated. A mechanistic pathway of the catalytic oxidation was tentatively described and discussed. Graphical AbstractKeywords Cu(II) Schiff base complexes · TEM · Benzyl alcohol · Density Functional Theory · Catalytic activity · Hydrogen peroxide

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“…40 Some of these ligands might also undergone excited-state intramolecular proton transfer (ESIPT). [41][42][43][44][45][46][47][48] This process involves a keto (K * ) ↔enol (E * ) balance in the electronic excited state of molecules containing intramolecular H-bonds. 49,50 The electronic absorption of energy by N,N'-bis(salicylidenes) in the ground state leads to an excited electronic state in the enol form.…”

Section: Introductionmentioning

confidence: 99%

Structural Correlations between Luminescent Properties and Excited State Internal Proton Transfer in Some Zinc(II) N,N′-Bis(salicylidenes)

et al. 2015

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In this study two salicylidene ligands, N,N'-bis(salicylidene)-1,2-phenylenediamine and N,N'-bis(salicylidene)-4,5-diaminopyrimidine, and their respective aquo-zinc(II) coordination compounds were synthesized. Their characterization was performed by FTIR, proton and carbon NMR, elemental analysis,mass spectroscopy and cyclic voltammetry. Crystal structures of the ligands were determined by monocrystal X-ray diffraction. The photoluminescent properties under photostationary conditions indicate that the ligand emission predominates in both the pristine materials and their zinc(II)complexes. For both ligands, the coordination of a metal atom leads to a redshift of their emission bands in both solvent and solid state. Molecular structures and excitation energies of ligands and complexes were evaluated at DFT level using PBE0/aug-cc-pVDZ. Their ligand and complex electronic transitions can be assigned mainly to the intraligand π→π * type, mainly involving frontier molecular orbitals, with a small participation of the metal. According to our calculations, there is an increasing in the planarity of the ligand structure in the complex, which could explain the redshifting observed in the absorption and emission spectra. The dynamic photoluminescence suggests the occurrence of excited state intramolecular proton transfer from the oxygen to the nitrogen atoms in the coordination site of the sal-4,5-pym.Moreover, they are able to predict the occurrence of the excited state internal proton transfer for the sal-4,5-pym. The dynamic of this proton transfer is demonstrated by both, time resolved emission spectra (TRES) and studies in protic solvent (ethanol).

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Dioxo and oxo-peroxo molybdenum(VI) complexes bearing salicylidene 2-picoloyl hydrazone: Structures and catalytic performances

Cited by 63 publications

References 32 publications

Excellent alkene epoxidation catalytic activity of macrocyclic‐based complex of dioxo‐Mo(VI) on supermagnetic separable nanocatalyst

Excellent alkene epoxidation catalytic activity of macrocyclic‐based complex of dioxo‐Mo(VI) on supermagnetic separable nanocatalyst

Some New Nano-sized Mononuclear Cu(II) Schiff Base Complexes: Design, Characterization, Molecular Modeling and Catalytic Potentials in Benzyl Alcohol Oxidation

Structural Correlations between Luminescent Properties and Excited State Internal Proton Transfer in Some Zinc(II) N,N′-Bis(salicylidenes)

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