Development of an efficient magnetically separable nanocatalyst: theoretical approach on the role of the ligand backbone on epoxidation capability

Adhikary, Jaydeep; Datta, Arnab; Dasgupta, Sanchari; Chakraborty, Aratrika; Menéndez, María Isabel Menéndez; Chattopadhyay, Taraprasad

doi:10.1039/c5ra17484h

Cited by 52 publications

(54 citation statements)

References 80 publications

(35 reference statements)

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“…As for Mn complexes, initial high‐spin Fe complexes (spin multiplicity =6) are more stable than the low‐spin ones (spin multiplicity =4), but now the difference between them amounts to 11 kcal mol −1 on average. However, final iron oxidized complexes present similar absolute energy, as previously reported for analogous systems . It is noteworthy that theoretical geometry of 5 in the stable high‐spin state is in agreement with experimental X‐ray measurements previously discussed.…”

Section: Resultssupporting

confidence: 88%

“…Here we examined the epoxidation of three alkenes, ( E )‐stilbene, ( Z )‐stilbene or styrene, catalysed by complexes 1 – 6 in CH 3 CN, with PhIO as terminal oxidant. Based on our previous studies, we only consider CH 3 CN as solvent. Table presents the conversion, turnover number (TON) and isolated yield for the epoxidation of the alkenes.…”

Section: Resultsmentioning

confidence: 99%

“…iodosylbenzene (PhIO), NaOCl and H 2 O 2 . The extensive use of metal salen complexes in homogeneous catalysis can be attributed to their high activity, selectivity and enantioselectivity (when chiral complexes are used) . The easy availability of active sites of homogeneous catalysts enhances their efficiency, but their liability lies in the difficulty in their separation from reaction mixtures.…”

Section: Introductionmentioning

confidence: 99%

“…Several research groups have recently investigated steric and electronic effects of manganese and non‐heme iron complexes on alkene epoxidations, and our own research team has given a deeper insight into the effect of halogen substituents at the ligand backbone of Schiff base Fe(III) complexes on epoxide yield . The relevance of the topic encourages us to delve further, by exploring the effect of alkyl groups at the non‐aromatic chain of the ligands.…”

Section: Introductionmentioning

confidence: 99%

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A route to magnetically separable nanocatalysts: Combined experimental and theoretical investigation of alkyl substituent role in ligand backbone towards epoxidation ability

Chattopadhyay

Chakraborty

Dasgupta

et al. 2016

Applied Organom Chemis

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We have prepared two chiral Schiff base ligands, H2L1 and H2L2, and one achiral Schiff base ligand, H2L3, by treating 2,6‐diformyl‐4‐methylphenol separately with (R)‐1,2‐diaminopropane, (R)‐1,2‐diaminocyclohexane and 1,1′‐dimethylethylenediamine, in ethanolic medium, respectively. The complexes MnL1ClO4 (1), MnL2ClO4 (2), MnL3ClO4 (3), FeL1ClO4 (4), FeL2ClO4 (5) and FeL3ClO4 (6) have been obtained by reacting the ligands H2L1, H2L2 and H2L3 with manganese(III) perchlorate or iron(III) perchlorate in methanol. Circular dichroism studies suggest that ligands H2L1 and H2L2 and their corresponding complexes have asymmetric character. Complexes 1–6 have been used as homogeneous catalysts for epoxidation of alkenes. Manganese systems have been found to be much better than iron counterparts for alkene epoxidation, with 3 as the best catalyst among manganese systems and 6 as the best among iron systems. The order of their experimental catalytic efficiency has also been rationalized by theoretical calculations. We have observed higher enantiomeric excess product with catalysts 1 and 4, so they were attached to surface‐modified magnetic nanoparticles to obtain two new magnetically separable nanocatalysts, Fe3O4@dopa@MnL1 and Fe3O4@dopa@FeL4. They have been characterized and their alkene epoxidation ability has been investigated. These catalysts can be easily recovered by magnetic separation and recycled several times without significant loss of catalytic activity. Hence our study focuses on the synthesis of a magnetically recoverable asymmetric nanocatalyst that finds applications in epoxidation of alkenes and at the same time can be recycled and reused.

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Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A route to magnetically separable nanocatalysts: Combined experimental and theoretical investigation of alkyl substituent role in ligand backbone towards epoxidation ability

Chattopadhyay

Chakraborty

Dasgupta

et al. 2016

Applied Organom Chemis

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“…In their turn, Cavallo and Jacobsen showed that oxo-Mn(acacen)Cl may be formed by a simple oxygen-transfer step between hypochlorite and Mn(acacen)Cl in aqueous solution [48]. More recently, Adhikary and co-workers [49] proposed the formation of an oxo-Fe(salen) species from iodosylbenzene (PhIO) and Fe(salen), which would be the active species in the iron-catalyzed epoxidation of stilbene. Similar intermediate species were also proposed by other authors [13,33,[50][51][52][53][54], indicating a strong consensus around the nature of the active catalyst of the epoxidation process.…”

Section: Insights On the Reaction Mechanismmentioning

confidence: 99%

Strengths, Weaknesses, Opportunities and Threats: Computational Studies of Mn- and Fe-Catalyzed Epoxidations

Teixeira

Cordeiro

2016

Catalysts

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Abstract:The importance of epoxides as synthetic intermediates in a number of highly added-value chemicals, as well as the search for novel and more sustainable chemical processes have brought considerable attention to the catalytic activity of manganese and iron complexes towards the epoxidation of alkenes using non-toxic terminal oxidants. Particular attention has been given to Mn(salen) and Fe(porphyrin) catalysts. While the former attain remarkable enantioselectivity towards the epoxidation of cis-alkenes, the latter also serve as an important model for the behavior of cytochrome P450, thus allowing the exploration of complex biological processes. In this review, a systematic survey of the bibliographical data for the theoretical studies on Mn-and Fe-catalyzed epoxidations is presented. The most interesting patterns and trends are reported and finally analyzed using an evaluation framework similar to the SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis performed in enterprise media, with the ultimate aim to provide an overview of current trends and areas for future exploration.

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Bis‐dioxomolybdenum (VI) oxalyldihydrazone complexes: Synthesis, characterization, DFT studies, catalytic epoxidation potential, molecular modeling and biological evaluations

Adam

Ahmed

Elhady

et al. 2020

Applied Organom Chemis

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Two cis‐bis‐dioxomolybdenum oxalylsalicylidenedihydrazone complexes (MoO2L1 and MoO2L2) were synthesized via the complexation of dioxomolybdenum (VI) acetylacetonate with oxalylsalicylidenedihydrazone (H2L1) and p‐sodium sulfonate oxalylsalicylidenedihydrazone (H2L2) bis‐Schiff base chelating ligands, respectively. The structures of the newly synthesized complexes were confirmed by 1H‐ and 13C‐NMR, IR, ultraviolet–visible and mass spectra, as well as elemental analyses (EA) and conductivity measurements. The spectrophotometric continuous variation method revealed the formation of 2: 1 (metal: ligand molar ratios). DFT studies were applied for the ligands and their Mo‐chelates. Interestingly, the bis‐MoO2(VI) oxalyldihydrazone complexes showed remarkable catalytic sufficiency towards the selective (ep)oxidation of 1,2‐cyclooctene, benzyl alcohol and thiophene using H2O2 or tert‐butyl hydroperoxide (tBuOOH) at 85 °C. Under aqueous conditions, the MoO2L2 (with p‐sodium sulfonate substituent) exhibited superior that of the MoO2L1 (without p‐NaSO3―group), highlighting the role of sodium sulfonate substituent in the catalytic progress of the Mo‐chelate. The ligands (H2L1 and H2L2) and their corresponding Mo‐complexes (MoO2L1 and MoO2L2) were assessed for their antitumor and antimicrobial activities. Furthermore, the antioxidant activity was also evaluated using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and superoxide dismutase (SOD) assays. The binding nature between the Mo‐complexes and calf thymus DNA (ctDNA) was also studied within spectroscopic and hydrodynamic techniques.

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Development of an efficient magnetically separable nanocatalyst: theoretical approach on the role of the ligand backbone on epoxidation capability

Abstract: The epoxidation property of an asymmetric iron complex has been experimentally and theoretically verified. This catalyst further conjugated with dopamine modified Fe3O4 to obtain magnetically separable nano-catalyst.

Cited by 52 publications

References 80 publications

A route to magnetically separable nanocatalysts: Combined experimental and theoretical investigation of alkyl substituent role in ligand backbone towards epoxidation ability

A route to magnetically separable nanocatalysts: Combined experimental and theoretical investigation of alkyl substituent role in ligand backbone towards epoxidation ability

Strengths, Weaknesses, Opportunities and Threats: Computational Studies of Mn- and Fe-Catalyzed Epoxidations

Bis‐dioxomolybdenum (VI) oxalyldihydrazone complexes: Synthesis, characterization, DFT studies, catalytic epoxidation potential, molecular modeling and biological evaluations

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