Sustainable synthesis of magnetically separable SiO2/Co@Fe2O4 nanocomposite and its catalytic applications for the benzimidazole synthesis

• Published in: Journal of magnetism and magnetic materials 2018-04, Vol.451, p.808-821
• Main Authors: Jithendra Kumara, K.S., Krishnamurthy, G., Sunil Kumar, N., Naik, Nagaraja, Praveen, T.M.
• Format: Article
• Language: English
• Subjects: Benzimidazole; Ferromagnetism; Magnetic nanoparticles; Nanocatalyst; Raman spectroscopy; X-ray photoelectron spectroscopy (XPS)
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2017.10.125

This manuscript demonstrate opportune synthesis of magnetically separable SiO2Co@Fe2O4 and Co@Fe2O4 Nanocomposite this nanoparticles are well characterized by more accurate spectroscopic techniques and finding the stabilizing power of the SiO2 over the nanoparticles. These nanoparticles are used as a catalyst for C–N cross-coupling reactions for benzimidazole synthesis. [Display omitted] •The SiO2 coated Co@Fe2O4 were synthesized by using chemical synthesis method.•Effect of diamagnetic SiO2 coating were studied with respect to size reduction.•Highly active catalyst were synthesized via chemical synthesis method.•Develop a new protocol for synthesis of Benzimidazole via C–N coupling reaction.•The result helpful in the field of nanoparticle synthesis and biomedical application. The Co(II) and Fe(III) centres magnetically separable two new mesoporous nanocatalyst were synthesised via chemical synthesis method. The transmission electron microscopic studies (TEM) show that, the particles are spherical shape with mean size of 20 nm. The Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) reveals that SiO2 is coating on the surface of the cobalt ferrate nanoparticle (CoFe2O4). The SiO2 coating is efficiently preventing the aggregated collision of nanoparticles. Magnetic measurements show that diamagnetic character of the SiO2 is unaffected to the coercivity of SiO2 coated CoFe2O4 particles. In addition, these nanoparticles are used as nanocatalyst for high yielding, facile and expeditious synthesis of various functionalized 2-arylbenzimidazoles via one-pot condensation. The cascade including imine formation, cyclization, condensation, and aromatization occurs, without addition of any reducing or oxidizing agents. In all situations, the desired product was synthesised with excellent yield. The shorter reaction time, mild reaction condition, simplicity, non-toxicity, safe reaction and easy workup are the impotent merits of this protocol. In SiO2 coated CoFe2O4 particles SiO2 serves as an efficient capping agent and prevent the aggregation of nanoparticles hence reducing the particle size, this cascade open up with stoichiometric quantity of using SiO2 with unaffected ferromagnetism of CoFe2O4 particles along with reducing the particle size. In addition SiO2 coated CoFe2O4 particles act as a highly efficient nanocatalytic, this method can be extended to the development of other catalytic system used in the synthesis of important pharmacological drungs. Mo