Evidence for H-bonding interactions to the mu-eta2:eta2-peroxide of oxy-tyrosinase that activate its coupled binuclear copper site.
Chemical communications (Cambridge, England)
The factors that control the diverse reactivity of the mu-eta2:eta2-peroxo dicopper(II) oxy-intermediates in the coupled binuclear copper proteins remain elusive. Here, spectroscopic and computational methods reveal H-bonding interactions between active-site waters and the mu-eta2:eta2-peroxide of oxy-tyrosinase, and define their effects on the Cu(II)2O2 electronic structure and O2 activation.
View details for DOI 10.1039/d2cc00750a
View details for PubMedID 35237779
Impact of Intramolecular Hydrogen Bonding on the Reactivity of Cupric Superoxide Complexes with O-H and C-H Substrates.
Angewandte Chemie (International ed. in English)
A series of TMPA-based copper(I) complexes (TMPA ≡ tris(2-pyridylmethyl)amine), with and without secondary coordination sphere hydrogen-bonding moieties, were prepared and reactivity with O2 at -135 °C in 2-methyltetrahydrofuran (MeTHF) was studied. H-bonding moieties are demonstrated to play a crucial role in the kinetic stabilization of [((X1)(X2)TMPA)CuII(O2•-)]+ cupric superoxide species, sustaining these primary copper-dioxygen compounds rather than subsequent secondary dicopper-dioxygen adducts. Support for the presence of H-bonding to the Cu-O-O•- superoxide O-atom(s) comes from resonance Raman (rR) spectroscopy, analogy to azido analogues [((X1)(X2)TMPA)CuII(N3-)]+, and the alternative O2 reactivity behavior of ligand-CuI complexes when an H-bonding modality is replaced by a methyl group. A dramatic enhancement in cupric superoxide reactivity towards phenolic substrates, as well as oxidation of substrates possessing moderate C-H BDEs is observed, correlating with the number and strength of the H-bonding groups.
View details for DOI 10.1002/anie.201908471
View details for PubMedID 31469942