Dataset Information

Direct Determination of Electron-Transfer Properties of Dicopper-Bound Reduced Dioxygen Species by a Cryo-Spectroelectrochemical Approach.

ABSTRACT: Direct experimental determination of redox properties of superoxo (O2.- ) and peroxo (O22- ) embedded in dicopper complexes bearing an unsymmetrical binucleating ligand was achieved using cryo-electrochemistry and cryo-spectroelectrochemistry in dichloromethane. Cyclic voltammetry for dicopper(I) (1+ ) oxidation to a CuI CuII mixed-valent species (12+ ) under inert atmosphere at 193?K reveals slow heterogeneous electron-transfer kinetics, indicative of a large reorganization energy. Oxygenation of the dicuprous complex?1+ gives the bridged peroxo dicopper(II) species?3+ , which is reversibly oxidized to the superoxo complex?22+ at E0 =0.11?V (vs. SCE) with a small inner sphere electron-transfer reorganization energy, ?i =0.54?eV, determined from variable temperature electrochemical impedance spectroscopy. The data suggest that the O2.- /O22- redox process occurs directly on the O2 -derived core.

SUBMITTER: Lopez I

PROVIDER: S-EPMC5783699 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Direct Determination of Electron-Transfer Properties of Dicopper-Bound Reduced Dioxygen Species by a Cryo-Spectroelectrochemical Approach.

López Isidoro I Cao Rui R Quist David A DA Karlin Kenneth D KD Le Poul Nicolas N

Chemistry (Weinheim an der Bergstrasse, Germany) 20171130 72

Direct experimental determination of redox properties of superoxo (O2.- ) and peroxo (O22- ) embedded in dicopper complexes bearing an unsymmetrical binucleating ligand was achieved using cryo-electrochemistry and cryo-spectroelectrochemistry in dichloromethane. Cyclic voltammetry for dicopper(I) (1+ ) oxidation to a CuI CuII mixed-valent species (12+ ) under inert atmosphere at 193 K reveals slow heterogeneo ...[more]

PMID: 29073346

Similar Datasets

Project description:X-ray crystallography and cryo-electron microscopy (cryo-EM) are complementary techniques for structure determination. Crystallography usually reveals more detailed information, while cryo-EM is an extremely useful technique for studying large-sized macromolecules. As the gap between the resolution of crystallography and cryo-EM data narrows, the cryo-EM map of a macromolecule could serve as an initial model to solve the phase problem of crystal diffraction for high-resolution structure determination. FSEARCH is a procedure to utilize the low-resolution molecular shape for crystallographic phasing. The IPCAS (Iterative Protein Crystal structure Automatic Solution) pipeline is an automatic direct-methods-aided dual-space iterative phasing and model-building procedure. When only an electron-density map is available as the starting point, IPCAS is capable of generating a completed model from the phases of the input map automatically, without the requirement of an initial model. In this study, a hybrid method integrating X-ray crystallography with cryo-EM to help with structure determination is presented. With a cryo-EM map as the starting point, the workflow of the method involves three steps. (1) Cryo-EM map replacement: FSEARCH is utilized to find the correct translation and orientation of the cryo-EM map in the crystallographic unit cell and generates the initial low-resolution map. (2) Phase extension: the phases calculated from the correctly placed cryo-EM map are extended to high-resolution X-ray data by non-crystallographic symmetry averaging with phenix.resolve. (3) Model building: IPCAS is used to generate an initial model using the phase-extended map and perform model completion by iteration. Four cases (the lowest cryo-EM map resolution being 6.9 Å) have been tested for the general applicability of the hybrid method, and almost complete models have been generated for all test cases with reasonable Rwork/Rfree. The hybrid method therefore provides an automated tool for X-ray structure determination using a cryo-EM map as the starting point.

Dataset Information

Direct Determination of Electron-Transfer Properties of Dicopper-Bound Reduced Dioxygen Species by a Cryo-Spectroelectrochemical Approach.

Publications

Direct Determination of Electron-Transfer Properties of Dicopper-Bound Reduced Dioxygen Species by a Cryo-Spectroelectrochemical Approach.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets