Melamine-Schiff base/manganese complex with denritic structure: An efficient catalyst for oxidation of alcohols and one-pot synthesis of nitriles

Milad Kazemnejadi; Mahsa Nikookar; Mohammad Mohammadi; Alireza Shakeri; Mohsen Esmaeilpour

doi:10.1016/j.jcis.2018.05.045

Melamine-Schiff base/manganese complex with denritic structure: An efficient catalyst for oxidation of alcohols and one-pot synthesis of nitriles

J Colloid Interface Sci. 2018 Oct 1:527:298-314. doi: 10.1016/j.jcis.2018.05.045. Epub 2018 May 18.

Authors

Milad Kazemnejadi¹, Mahsa Nikookar², Mohammad Mohammadi², Alireza Shakeri³, Mohsen Esmaeilpour⁴

Affiliations

¹ Department of Chemistry, College of Science, Shiraz University, Shiraz 7194684795 Iran; Department of Chemistry, College of Science, Golestan University, Gorgan 4917774979, Iran. Electronic address: miladkazemnejad@yahoo.com.
² Department of Chemistry, College of Science, Golestan University, Gorgan 4917774979, Iran.
³ Faculty of Chemistry, College of Science, University of Tehran, Tehran 1417466191, Iran.
⁴ Department of Chemistry, College of Science, Shiraz University, Shiraz 7194684795 Iran. Electronic address: mohsen.esmaeilpour1250@gmail.com.

PMID: 29800879
DOI: 10.1016/j.jcis.2018.05.045

Abstract

Efficient and selective oxidation of alcohol to the corresponding carbonyl and/or nitrile was carried out by a new water-soluble melamine-based dendritic Mn(III) complex (Melamine-Mn (III)-Schiff base complex) in the presence of 2,4,6-trichloro-1,3,5-triazine (TCT) and O₂ at room temperature. Also, the oxidation of amine to the corresponding nitrile with high selectivity and conversion was performed at room temperature using the current method and high amounts of turnover frequencies (TOFs) were obtained for reactions. This system was also applicable for direct preparation of oxime through oxidation of alcohol. The catalyst was characterized by Fourier-transform infrared (FTIR), ultraviolet-visible (UV-Vis), thermogravimetric analysis (TGA), energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), CHN and inductively coupled plasma (ICP) analyses. Also, oxidation/reduction behavior of the catalyst was studied by cyclic voltammetry (CV). Moreover, chemoselectivity of the catalyst was discussed with various combinations. The water-soluble catalyst could be recycled from the reaction mixture and reused for several times with a very low losing in efficiency. The recovered catalyst was also investigated with various analyses. Finally, gram scale preparation of nitrile was evaluated by present method.

Keywords: Alcohol oxidation; Amine oxidation; Mn(III) complex; Nitriles; Reusable; Water-soluble catalyst.