DFT studies of the effectiveness of p-substituted diphenyl amine antioxidants in styrene-butadiene rubber through their Cu(II) coordination ability

Quantum-chemical study of the active sites of camptothecin through their Cu(II) coordination ability

“…The aim of this study was to quantify and subsequently compare the toxicity of active sites in the camptothecin lactone form through the method of copper(II) ion probe [Alagona and Ghio, 2009a;Alagona and Ghio, 2009b;Mammino, 2013;Puškárová and Breza, 2016;Puškárová and Breza, 2017]. We have shown that both nitrogen atoms in the CPT structure are inactive and we have concluded that the heteroatom with the highest affinity to Cu(II) (as the model of radicals) in camptothecin is oxygen on carbon C 21 .…”

“…Consequently, the charge and the spin density of copper can be used to measure affinity of the CPT active sites. The extent of electron density transfer between Cu(II) ion and CPT molecule can be evaluated calculating the Laplacian of electron density at Cu-N/Cu-O bond critical points [Puškárová and Breza, 2016;Puškárová and Breza, 2017].…”

Quantum‐chemical studies of the antioxidant effectiveness of para‐phenylene diamines

“…[99] NMR chemical shifts [72,73] are indirect descriptors only, but are much less dependent on molecular conformations. The indirect descriptors based on the formation of the Cu(II) complex formation and related electron density transfer [77][78][79][80][81][82][83][84][85][86] do not depend on molecular conformations, but are not suitable for carbon active sites and require exclusive Cu-N bonding. Nevertheless, we can conclude similar trends obtained by all of these treatments.…”

“…The method of quantum-chemical prediction of antioxidant activity based on the Cu 2+ coordination ability of antioxidant active sites with subsequent electron density transfer [77][78][79][80][81][82][83][84][85][86][87][88] has been known for years. It is based on the idea that the formation of the Cu complex causes that the Cu 2+ spin population decreases simultaneously with the increasing ligand spin population (up to one).…”

Highly dispersed Pt catalyst supported on nanoporous carbon derived from waste PET bottles for reductive alkylation

“…An important class of these alkylated amines is N,N 0 -disubstituted p-phenylenediamine (DPPD), which plays an signicant role in rubber additives. [1][2][3][4][5][6][7][8] The reductive alkylation for DPPDs is carried out by condensation reaction between p-phenylenediamine compounds and ketones to form imines, 9 also known as Schiff bases, which are converted to N-alkylated products via catalytic hydrogenation. [10][11][12] CuO-ZnO-Al 2 O 3 composite catalysts were widely used in industrial production of DPPDs because of their low cost.…”