Abstract
One-dimensional (1D) polynuclear Cu(II) complex (1) derived from (5-bromo-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L) is synthesized and characterized by elemental analysis, IR spectroscopy, ESI-MS, and single crystal X-ray crystallography. Its catalytic performance towards the solvent-free microwave-assisted peroxidative oxidation of aliphatic and aromatic hydrocarbons under mild conditions is compared with that of dinuclear Cu(II) complexes (2 and 3) of the same ligand, previously reported as antiproliferative agents. Polymer 1 exhibits the highest activity, either for the oxidation of cyclohexane (leading to overall yields, based on the alkane, of up to 39% of cyclohexanol and cyclohexanone) or towards the oxidation of toluene (selectively affording benzaldehyde up to a 44% yield), after 2 or 2.5 h of irradiation at 80 or 50 °C, respectively.
Highlights
The search for efficient routes for the mild oxidative functionalization of hydrocarbons, in particular of inert alkanes, to valuable commodities using suitable catalysts is a demanding research area of high industrial significance [1,2,3]
It was previously observed that the reaction of the aroylhydrazone with a Cu(II) salt of a base of
It was previously observed that the reaction of the aroylhydrazone with a Cu(II) salt of a base of a strong acid yielded an aroylhydrazone-Cu(II) complex in the keto form, whereas a Cu(II) salt of a base of a weak acid produced a Cu(II) complex with the enol form [20,23]
Summary
The search for efficient routes for the mild oxidative functionalization of hydrocarbons, in particular of inert alkanes, to valuable commodities using suitable catalysts is a demanding research area of high industrial significance [1,2,3]. Alkanes are relatively cheap and highly abundant raw materials for the direct synthesis of added-value functionalized products, due to their chemical inertness, the design of active and selective catalysts for the atom-efficient and selective oxidation of the low reactive C–H bond continues to be a real challenge [4,5,6,7]. The rationale to design synthetic bio-inspired catalyst precursors for functionalizing the non-activated C–H bonds of hydrocarbons is based on metallic complexes, where the metal center can undergo reversible redox processes. The most tested transition metal complexes as catalysts for such oxidation reactions bear tridentate pincer [8,9,10,11] or scorpionate [4,5,12] ligands, or are coordination polymers [13], metal-based pocket structures (e.g., cyclodextrins or calixarenes) [14], or metal–organic frameworks [15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
