Complexity with simplicity: a steric continuum of chelating diamines with copper(i) and dioxygen

Tuning of Copper(I)–Dioxygen Reactivity by Bis(guanidine) Ligands

“…As has been shown by Stack et al, bidentate N-donor ligands are also capable of forming complexes containing the heterocyclic Cu 2 O 2 core portion. [4,16,17] The associated square-planar CuO 2 N 2 coordination sites are expected to be more accessible for external substrates that may act as targets for catalytic oxygenation reactions. [18][19][20] Following this approach, peralkylated diamine ligands have been used to stabilise either the bis(µ-oxo)dicopper() (Ocore complexes) or the µ-η 2 :η 2 -peroxodicopper() core portion (P-core complexes) depending on the type of substituents.…”

“…Investigations directed towards an understanding of the mechanisms and a transformation of such processes to technical applications are among the most important research objectives not only in bioinorganic chemistry but also in numerous and diverse arrays of catalytic oxidation reactions. [1][2][3][4][5][6][7] From X-ray structure determinations of the blood dioxygen carrier hemocyanin (for example in arthropods and molluscs) [7,8] it is known that the protein active sites consist of µ-η 2 :η 2 -peroxodicopper() units where each copper ion binds three supporting exogenic N-donor functions originating from histidine imidazole groups. Spectroscopic comparisons suggest that this binding mode occurs also in tyrosinases (phenol Ǟ o-quinone) [9] and catechol oxidases (ocatechol Ǟ o-quinone).…”

Theoretical Characterization of End-On and Side-On Peroxide Coordination in Ligated Cu2O2 Models

“…2, [10][11][12][13][14][15][16][17][18] There are several motifs for the binding of molecular O 2 to two supported copper(I) atoms ( Figure 1). 12,19 Best characterized experimentally (because they have been observed for many different supporting ligand sets) are the side-on µ-η 2 :η 2 peroxo and the bis(µ-oxo). The trans end-on µ-η 1 :η 1 peroxo motif was first described by Jacobson et al 20 This binding mode is preferred when the copper atoms are supported by tripodal tetradentate ligands, [21][22][23][24][25] although when such ligands become too sterically demanding for trigonal bipyramidal coordination of copper a preference for the bis(µ-oxo) motif with concomitant loss of two ligand-copper interactions has been documented.…”

Dinuclear copper–dioxygen intermediates supported by polyamine ligands

“…Reactive intermediates derived from the reactions of copper(I) complexes with O 2 and copper(II) complexes with H 2 O 2 play central roles in many biological and catalytic oxidation processes [1][2][3][4][5]. Among a series of copper-active oxygen species, dinuclear copper-dioxygen complexes (Cu 2 /O 2 ) have been most extensively studied in model systems [1][2][3][4][5].…”

“…Among a series of copper-active oxygen species, dinuclear copper-dioxygen complexes (Cu 2 /O 2 ) have been most extensively studied in model systems [1][2][3][4][5]. The Cu 2 /O 2 complexes have been generally prepared by self-assembling reaction of mononuclear copper(I) complexes and O 2 [1][2][3][4][5].…”