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Choudary, B. M.; Chowdari, Naidu S.; Kantam, M. Lakshmi; Santhi, P. Lakshmi

doi:10.1023/a:1012317827817

Cited by 40 publications

(18 citation statements)

References 8 publications

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“…The experimental procedure for the synthesis of L 4 was carried out as described previously [22,23] with minor modification. Yield 58%.…”

Section: Synthesis Of Salen Ligand Lmentioning

confidence: 99%

“…[22,24] The pyrrolidine salen ligand (1 mmol) was dissolved in hot toluene-ethanol (45 ml, 1 : 2, v/v) and solid Mn(OAc) 2 · 4H 2 O (0.735 g, 3 mmol) was added in one portion. The solution was heated to reflux for 2 h, then LiCl (0.126 g, 3 mmol) was added and the mixture was further refluxed for 3 h while air was bubbled through the refluxing mixture.…”

Section: Synthesis Of Pyrrolidine Salenmn(iii) Complexesmentioning

confidence: 99%

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Asymmetric epoxidation of chromenes catalyzed by chiral pyrrolidine SalenMn(III) complexes with an anchored functional group

Zhang

Wang

Jia

et al. 2008

Applied Organom Chemis

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Chiral pyrrolidine SalenMn(III) complexes with an anchored functional group at the N aza -substituent in the pyrrolidine backbone were synthesized, and used as catalysts for asymmetric epoxidation of substituted chromenes. The complex 1 with an anchored imidazole as acceptor could effectively catalyze epoxidation of substituted chromenes in the absence of expensive additive 4-phenyl pyridine N-oxide (PPNO) by the coordination of the anchored organic base to the central manganese ion. Complexes 2 and 3 with a quaternary ammonium salt unit at the N aza -substituent in the pyrrolidine backbone displayed higher activities than Jacobsen catalyst and the analogous complex 4 without anchored functional group in the aforementioned reaction. Copyright

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“…The experimental procedure for the synthesis of L 4 was carried out as described previously [22,23] with minor modification. Yield 58%.…”

Section: Synthesis Of Salen Ligand Lmentioning

confidence: 99%

Section: Synthesis Of Pyrrolidine Salenmn(iii) Complexesmentioning

confidence: 99%

Asymmetric epoxidation of chromenes catalyzed by chiral pyrrolidine SalenMn(III) complexes with an anchored functional group

Zhang

Wang

Jia

et al. 2008

Applied Organom Chemis

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“…counterparts [40,41]. Unfortunately, although wellbehaved catalysts are known [38,[42][43][44], no general immobilization methodology exists that is applicable for all (or even most) metal complexes.…”

Section: Long Term Challenges For Oxide-tethered Metal Complex Catalymentioning

confidence: 99%

Design of silica-tethered metal complexes for polymerization catalysis

et al. 2005

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Metal complex catalysts that are covalently tethered to oxide supports have been utilized for many years as hybrid molecular/ heterogeneous catalysts. In this work, recent results from our laboratory in the area of silica-tethered metal complex polymerization catalysts are reviewed. The critical parameters for catalyst design when catalyst recovery and recycle are important are discussed in the context of silica-immobilized CuBr complexes for atom transfer radical polymerization (ATRP) as well as silica-tethered Zn-bdiiminate (BDI) complexes for lactide or epoxide/CO 2 polymerization. Additionally, a new strategy for the preparation of siteisolated metal complex catalysts on a silica surface is illustrated through the design of tethered constrained geometry catalysts (CGCs) for ethylene polymerization. The novel synthetic protocol is demonstrated to result in catalysts that appear to be more welldefined and that have improved catalytic properties. Major challenges and future directions in the field of oxide-tethered metal complex catalysis are discussed.

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“…[6,7] Ease of separation of the catalyst when it is in a different phase from the reactants/products is also a driver for the heterogenisation of such a system. Various degrees of success have been achieved by attaching the active chiral salen system to zeolites, [8] to polystyrene and polymethacrylate resin (polymer supported), [9] to silica via chloropropyl spacers, metallated with manganese [10] and using organo-functionalised mesoporous materials [11] as well as in the subsequent testing of the anchored systems in the epoxidation of alkenes. Kureshy et al [12] reported on dicationic chiral Mn (III) complexes immobilised between the layers of montmorillonite clay.…”

Section: Introductionmentioning

confidence: 99%

Novel Chiral Sulphonato‐Salen‐Manganese(III)‐Pillared Hydrotalcite Catalysts for the Asymmetric Epoxidation of Styrenes and Cyclic Alkenes

Bhattacharjee¹,

Anderson²

2006

Adv Synth Catal

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A novel chiral sulphonato-salen-manganese (III) complex has been prepared and intercalated into a Zn-Al layered-double hydroxide (LDH) structure. The resulting catalyst was found to be highly active and enantioselective in the epoxidation of various styrenes and cyclic alkenes when using a combination of pivalaldehyde and molecular oxygen at atmospheric pressure and room temperature. At 94% conversion, 1-methyl-1-cyclohexene could be converted to epoxide with 68% ee and 90% selectivity with a turnover frequency (TOF) of 234 h À 1 , whereas 4-methylstyrene was converted with 62% ee and 70% selectivity with a TOF of 327 h À 1 . In the case of styrenes and cyclic alkenes, TOF decreased as follows: a-methylstyrene > 4-methylstyrene > styrene and 1-methyl-1-cyclohexene > 1-phenyl-1-cyclohexene > cyclohexene. The catalyst could be recycled without detectable loss of efficiency.

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Cited by 40 publications

References 8 publications

Asymmetric epoxidation of chromenes catalyzed by chiral pyrrolidine SalenMn(III) complexes with an anchored functional group

Asymmetric epoxidation of chromenes catalyzed by chiral pyrrolidine SalenMn(III) complexes with an anchored functional group

Design of silica-tethered metal complexes for polymerization catalysis

Novel Chiral Sulphonato‐Salen‐Manganese(III)‐Pillared Hydrotalcite Catalysts for the Asymmetric Epoxidation of Styrenes and Cyclic Alkenes

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