Oxidation of Organic Functionalities by PhI(OAc)₂ Catalysed by Magnetically Separable Fe₃O₄@dopa‐Supported Mn(III) Complexes: Combined Experimental and Theoretical Approach

Abstract

Three newly designed ligands N, N′‐bis (3, 5‐diX)‐2, 2‐dimethylpropane‐1, 3 diamine, where X=Cl/Br/I (H2L1‐H2L3) having N2O2binding sites, have been chosen to synthesize mononuclear manganese(III) complexes 1–3 with an aim to study their catalytic activity towards oxidation of various substrates using PhI(OAc)2as a terminal oxidant. All these complexes have been characterized by routine physico‐chemical techniques. Complexes 1 (MnL1Cl ) and 2 (MnL2Cl ) have further been structurally characterized by X‐ray single crystal structure analysis. Detailed analysis of ESI‐MS, UV‐Vis and cyclic voltammetry studies along with theoretical calculations helped us to put forward probable mechanistic pathway for these efficient catalytic reactions. Complex 1exhibited the highest catalytic efficiency in every reaction and therefore it was selected for building a magnetically separable catalyst by attaching it to surface modified magnetic nanoparticles. The new Fe3O4@dopa@MnL1Cl(dopa=dopamine hydrochloride) [FDM‐1] catalyst was characterized by solid state UV‐VIS, FT‐IR, SEM, TEM, TGA, PXRD, EDX and SQUID analyses. The catalytic activity towards oxidation of various substrates by FDM‐1 was studied using PhI(OAc)2 and results indicated excellent efficiency along with reusability.

Surfactant-Mediated Solubilization of Magnetically Separable Nanocatalysts for the Oxidation of Alcohols

“…Prepared nano HCAT-1 shows absorption peaks at around 580 and 631 cm –1 , which are the characteristic absorptions of the Fe–O bond, confirming the presence of iron oxide, as previously reported. 20−23 Dopamine incorporation is confirmed by the presence of a peak around 1480 cm –1 , which can be attributed to the vibration of the benzene ring present at the dopamine moiety. In the case of CTAB-coated magnetically separable nanoparticle CHCAT-1, a bunch of peaks at 2846, 2914, and 2953 cm –1 can be attributed to the asymmetric and symmetric stretching of −CH 2 -moieties of the long alkyl chain of CTAB and the antisymmetric stretching mode of the trimethylammonium head group for CTAB are identified by a peak around 3015 cm –1 , which further proves the presence of CTAB at the surface of our synthesized magnetically separable nanoparticles CHCAT-1.…”

Triton X‐100 functionalized Cu(II) dihydrazone based complex immobilized on Fe3O4@dopa: A highly efficient catalyst for oxidation of alcohols, alkanes, and sulfides and epoxidation of alkenes

“…IR studies From the FT-IR spectrum ( Figure 2) of FDC, absorption peaks at 631 and 572 cm −1 confirm the presence of Fe 3 O 4 because these two peaks are the characteristic absorption of the Fe-O bonds. [55,56] Incorporation of dopamine moiety was established by the presence of a peak around 1478 cm −1 , the appearance of which can be attributed to the vibration of the benzene ring in dopamine molecule. Further, surface functionalization using Triton X-100 was confirmed by the presence of a peak at 1125 cm −1 , indicating C-O stretching vibrations of Triton X-100.…”

“…), IR, and electrospray ionizationmass spectrometry (ESI-MS) techniques. Also, as followup research on magnetically separable Fe 3 O 4 @dopabased supports for various organic transformations, [55,56] we report the fabrication and characterization of a watersoluble Cu(II)-Schiff base complex immobilized on dopamine-stabilized Fe 3 O 4 magnetic nanoparticles with a nonionic-based surfactant Triton X-100 (TX100/ Fe 3 O 4 @dopa@CuL) (FDCTX). This water-soluble nanocatalytic system affords the efficient oxidation of a wide range of substrates (Scheme 1) with the aid of a green oxidant H 2 O 2 , thereby rendering the present approach economical, safer, and environmentally benign.…”

Experimental and theoretical investigation of the catalytic performance of reduced Schiff base and Schiff base iron complexes: Transformation to magnetically retrievable catalyst

“…Alternative friendly oxidants later used included H 2 O 2 , [ 9 ] O 2 [ 10 ] or PhI (OAc) 2 . [ 11 ] Earlier reports of homogeneous alcohol oxidation catalyzed by iron came from Martin and Suárez in 2002 [ 12 ] where a binary system made of Fe (NO 3 ) 3 and FeBr 3 probed to be efficient and selective for the aerobic oxidation of secondary and aromatic alcohols. Later, Liu et al used the FeCl 3 –TEMPO–NaNO 2 catalytic system to execute selective oxidation of a wide range of alcohols to the corresponding aldehydes and ketones.…”