An asymmetric Salamo-based Zn complex supported on Fe3O4 MNPs: a novel heterogeneous nanocatalyst for the silyl protection and deprotection of alcohols under mild conditions

Fe3O4 supported [Cu(ii)(met)(pro-H)2] complex as a novel nanomagnetic catalytic system for room temperature C-O coupling reactions

In this study, a newly-designed copper(ii) complex of metformin and l-proline which was immobilized on Fe₃O₄ MNPs was developed. The structure of the catalyst platform was fully characterized using spectroscopic analyses. Moreover, the catalytic activity of [Fe₃O₄@Cu(ii)(Met)(Pro-H)₂] was investigated in a one-pot synthesis of a variety of functionalized ethers in reasonable to excellent yields through Ullman reaction in an aqueous environment using various aryl halides, phenol, and Cs₂CO₃ and without using any external Cu-reducing agents. Notably, gentle catalytic conditions, quick reaction times, applicability, low cost, and preventing dangerous chemicals and solvents during synthesis and catalytic application are some of the superior properties of the [Fe₃O₄@Cu(ii)(Met)(Pro-H)₂] complex. Furthermore, the catalyst can be reused for several runs (at least eight times) without remarkable loss in efficiency.

Nanomagnetic macrocyclic Schiff-base-Mn(ii) complex: an efficient heterogeneous catalyst for click approach synthesis of novel β-substitued-1,2,3-triazoles

In the present work, a novel symmetrical 15-membered macrocyclic Schiff base complex of manganese was prepared using the reaction of the synthetic 2,6-diacetylpyridine functionalized Fe₃O₄ MNPs with 2,2-(piperazine-1,4-diyl)dianiline and Mn(ii) bromide salt via a template approach. The resulting [Fe₃O₄@PAM-Schiff-base-Mn][ClO₄] heterogenized complex was characterized using FT-IR, XRD, BET, TGA, EDX, Xray-mapping, SEM, TEM and VSM analysis. To demonstrate proof of concept, Huisgen 1,3-dipolar cycloaddition synthesis of 1,2,3-triazoles was selected to evaluate the activity and reusability of the catalyst. The ethanol as a green solvent proved to be an excellent reaction medium for this synthesis. Yields of up to 100% were obtained in some cases. Significantly, as demonstrated, [Fe₃O₄@PAM-Schiff-base-Mn][ClO₄] catalyst was recycled for 8 cycles without losing catalytic activity under the optimized reaction conditions. The hot filtration and ICP-OES tests ratified that there was no leaching of metal during the catalytic reaction, indicating the heterogeneous manner of the catalyst.