Vanadyl β-tetrabromoporphyrin: synthesis, crystal structure and its use as an efficient and selective catalyst for olefin epoxidation in aqueous medium.
Vanadyl β-tetrabromoporphyrin: synthesis, crystal structure and its use as an efficient and selective catalyst for olefin epoxidation in aqueous medium.
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DOI：
10.1039/c8ra09825e
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发表时间：
2019-03-28
期刊：
影响因子：
3.9
通讯作者：
Maurya, Mannar Ram
中科院分区：
文献类型：
--
作者：
Dar, Tawseef Ahmad;Tomar, Reshu;Mian, Rasel Mohammad;Sankar, Muniappan;Maurya, Mannar Ram
本文报道了β-位上含溴取代基的钒基卟啉（1）的合成、表征及其在烯烃环氧化反应中的催化应用。采用紫外-可见光谱、红外光谱、EPR、MALDI-TOF质谱和单晶X射线衍射等光谱技术对合成的卟啉进行了表征。卟啉1具有非平面结构，如其X-射线结构，密度泛函理论和电化学研究所示。1在烯烃环氧化反应中的催化应用。催化反应在体积比为3：1的乙腈/水混合溶剂中进行。1的催化剂具有反应条件温和、反应温度低、催化剂用量少等优点。1在0.5 h的显著低反应时间内表现出优异的选择性、高转化效率和巨大的TOF（7600-9800 h-1）。催化剂1在各种催化循环结束时再生，使其可重复使用并具有工业重要性。合成了具有高热稳定性和非平面大环核的β-四溴-meso-四苯基卟啉氧化钒（IV）（VOTPPBr 4）。此外，它被用于烯烃的选择性环氧化，产率高，TOF数非常高。
We hereby report the synthesis, characterization and catalytic applications in the epoxidation of alkenes by a vanadyl porphyrin having bulky bromo substituents at the β-positions viz. vanandyltetrabromotetraphenylporphyrin (1). The synthesized porphyrin was characterized by various spectroscopic techniques like UV-visible, FT-IR, EPR, MALDI-TOF mass spectrometry and single crystal X-ray analysis. Porphyrin 1 has a nonplanar structure as indicated by its X-ray structure, DFT and electrochemical studies. 1 was analyzed for its catalytic application in the epoxidation of various alkenes. The catalytic reactions were carried out in CH3CN/H2O mixture in 3 : 1 (v/v) ratio. 1 displayed good efficiency in terms of mild reaction conditions, lower reaction temperature and minimal catalyst amount consumption. 1 exhibited excellent selectivity, high conversion efficiency and huge TOF (7600–9800 h−1) in a significantly low reaction time of 0.5 h. Catalyst 1 was regenerated at the end of various catalytic cycles making it reusable and industrially important. We have synthesized β-tetrabromo-meso-tetraphenylporphyrinatooxidovanadium(iv) (VOTPPBr4) which possesses high thermal stability and nonplanar macrocyclic core. Further, it was utilized for selective epoxidation of olefins in good yields with very high TOF numbers.
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影响因子：
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作者：
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通讯作者：
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影响因子：
2.1
作者：
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影响因子：
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