Mononuclear Copper(II)−Superoxo Complexes that Mimic the Structure and Reactivity of the Active Centers of PHM and DβM

Abstract

Mononuclear copper(II)-superoxo complexes 2(X)-OO(*) having triplet (S = 1) ground states were obtained via reaction of O(2) with the copper(I) starting materials 1(X) supported by tridentate ligands L(X) [1-(2-p-X-phenethyl)-5-(2-pyridin-2-ylethyl)-1,5-diazacyclooctane; X = CH(3), H, NO(2)] in various solvents. The superoxo complexes 2(X)-OO(*) mimic the structure [tetrahedral geometry with an end-on (eta(1))-bound O(2)(*-)] and the aliphatic C-H bond activation chemistry of peptidylglycine alpha-hydroxylating monooxygenase and dopamine beta-monooxygenase.

Spectroscopic and computational insight into the activation of O 2 by the mononuclear Cu center in polysaccharide monooxygenases

“…Cu-superoxide species have been proposed as reactive intermediates in H-atom abstraction in the noncoupled binuclear Cu enzymes (1,29,30), although a Cu(II)-superoxide enzyme species has yet to be spectroscopically characterized. Alternatively, a variety of inorganic Cu(II)-superoxide model complexes have been trapped at low temperature (31)(32)(33)(34)(35). These include a diazacyclooctane supported complex (1) (32) (SI Appendix, Fig.…”

Transition Metal Complexes and the Activation of Dioxygen

“…In support of this capability, complex 82 (R ¼ phenethyl group) decays to yield 86 ( Figure 40) via a pathway shown by kinetic experiments and DFT calculations to proceed by ratelimiting intramolecular hydrogen atom abstraction by the coordinated superoxide from the benzylic C-H bond of the ligand phenethyl arm [286,287].…”

“…While not yet characterized by X-ray crystallography, adducts 81-85 have been studied by spectroscopy and theory, which also support end-on Cu(II)-superoxo formulations [285][286][287][288][289][290][291]. Like 80, all are best described as having triplet ground states, with an initial report of 81 being a singlet [285] having been subsequently refuted through VTVH-MCD and NMR spectroscopy [291].…”

Synthesis and crystal structure of new dicopper(II) complexes having asymmetric N,N′-bis(substituted)oxamides with DNA/protein binding ability: In vitro anticancer activity and molecular docking studies

“…Along this line, lots of copper(II) complexes with different ligands have been widely studied [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], because copper, as a biologically relevant element, shows great effects on the endogenous oxidative DNA damage associated with aging and cancer and relates to many enzymatic activities which have been identified. Comparing the number of studies dealing with monocopper complexes [14][15][16][17][18][19][20][21][22], relatively few studies on dicopper(II) complexes have been reported to date. However, the enhancement of DNA-binding activity for dinuclear complexes prompts us to design and synthesize new dicopper(II) complexes in order to gain some insight into their DNA/protein binding property and antitumor activity of these kinds of complexes [23][24][25][26][27].…”