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Aroylhydrazone Schiff Base Derived Cu(II) and V(V) Complexes: Efficient Catalysts towards Neat Microwave-Assisted Oxidation of Alcohols

A new hexa-nuclear Cu(II) complex [Cu(3)(μ(2)-1κNO(2),2κNO(2)-L)(μ-Cl)(2)(Cl)(MeOH)(DMF)(2)](2) (1), where H(4)L = N′(1),N′(2)-bis(2-hydroxybenzylidene)oxalohydrazide, was synthesized and fully characterized by IR spectroscopy, ESI-MS, elemental analysis, and single crystal X-ray diffraction. Comple...

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Detalles Bibliográficos
Autores principales: Sutradhar, Manas, Roy Barman, Tannistha, Pombeiro, Armando J. L., Martins, Luísa M. D. R. S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7215666/
https://www.ncbi.nlm.nih.gov/pubmed/32325701
http://dx.doi.org/10.3390/ijms21082832
Descripción
Sumario:A new hexa-nuclear Cu(II) complex [Cu(3)(μ(2)-1κNO(2),2κNO(2)-L)(μ-Cl)(2)(Cl)(MeOH)(DMF)(2)](2) (1), where H(4)L = N′(1),N′(2)-bis(2-hydroxybenzylidene)oxalohydrazide, was synthesized and fully characterized by IR spectroscopy, ESI-MS, elemental analysis, and single crystal X-ray diffraction. Complex 1 and the dinuclear oxidovanadium(V) one [{VO(OEt)(EtOH)}(2)(1κNO(2),2κNO(2)-L)]·2H(2)O (2) were used as catalyst precursors for the neat oxidation of primary (cinnamyl alcohol) and secondary (1-phenyl ethanol, benzhydrol) benzyl alcohols and of the secondary aliphatic alcohol cyclohexanol, under microwave irradiation using tert-butyl hydroperoxide (TBHP) as oxidant. Oxidations proceed via radical mechanisms. The copper(II) compound 1 exhibited higher catalytic activity than the vanadium(V) complex 2 for all the tested alcohol substrates. The highest conversion was found for 1-phenylethanol, yielding 95.3% of acetophenone in the presence of 1 and in solvent and promoter-free conditions. This new Cu(II) complex was found to exhibit higher activity under milder reaction conditions than the reported aroylhydrazone Cu(II) analogues.