757238-67-8Relevant academic research and scientific papers
Synthesis, Characterization, and Catalytic Application of Mononuclear and Dendritic Cationic CuIIminopyridine-Ligated Complexes in Aryl Iodide Hydroxylation
Mketo, Nomvano,Jordaan, Johan H. L.,Jordaan, Anine,Swarts, Andrew J.,Mapolie, Selwyn F.
, p. 3781 - 3790 (2016)
A series of mononuclear (C1–C4) and dendritic G1 (DC1–DC4) and G2 (DC5–DC8) cationic CuIiminopyridine complexes of the general formula [Cu{(R-C5H3N)CH=N(nPr)-κ2-N,N}2][BF4] (C1: R = 6-Me; C2: R = H; C3: R = 6-Br; C4: R = C4H3) and [DAB-Gx-PPI-(Cu{(R-C5H3N)-κ2-N,N}y)z][BF4]n[DAB: 1,4-diaminobutane; PPI: poly(propyleneimine); for G1: x = 1, y = 4, z = 2, n = 2; for G2: x = 2, y = 8, z = 4, n = 4; DC1/DC5: R = 6-Me; DC2/DC6: R = H; DC3/DC7: R = 6-Br; DC4/DC8: R = C4H3] have been prepared and characterized by a range of spectroscopic and analytical techniques. The mononuclear and dendritic complexes were found to be active catalysts for the hydroxylation of 4-iodotoluene to p-cresol in DMSO/H2O mixtures. A positive dendritic effect on catalytic activity was observed. Furthermore, our catalyst system was found to be active for the hydroxylation of 4-iodotoluene in neat water. The active catalyst could be recycled twice before catalyst deactivation was observed. HRTEM analysis revealed that catalyst deactivation arose as a result of metal agglomeration. A series of poisoning experiments provided evidence for the mediation of hydroxylation by a homogeneous active species for both classes of pre-catalysts, and a radical-trapping experiment in combination with our experimental observations provided evidence that the reaction proceeds through a similar mechanism to that reported for Cu-catalyzed halide exchange.
Nickel metallodendrimers as catalyst precursors in the tandem oligomerization of ethylene and Friedel-Crafts alkylation of its olefinic products Metallodendrimers Special Issue
Malgas-Enus, Rehana,Mapolie, Selwyn F.
, p. 96 - 105 (2014/04/03)
The synthesis and catalytic activity of nickel metallodendrimers (C1-C6) are reported. The metallodendrimers were synthesized by the coordination of the metal precursors, Ni(OAc)2 and Ni(DME)Br2, to the periphery of salicylaldimine and iminopyridyl modified dendritic ligands, DL1-DL6, based on the generation 1 to generation 3 diaminobutane polypropylene imine (DAB-PPI) dendrimers. The metallodendrimers were tested in the oligomerization of ethylene and were found to be active catalysts. When using this catalyst system, it was found that a tandem process occurred in which ethylene oligomerization was followed by Friedel-Crafts alkylation of the reaction solvent, toluene. The latter process is mediated by the aluminium co-catalyst, EtAlCl2.
