Assessment of the isodesmic method in the calculation of standard reduction potential of copper complexes

Abstract

Molecular phenomena involving electron transfer and reduction/oxidation processes are of the utmost importance in chemistry. However, accurate computational calculations of standard reduction potentials (SRPs) for transition metal complexes are still challenging. For this reason, some computational strategies have been proposed in order to overcome the main limitations in SRP calculations for copper complexes. However, these strategies are limited to particular coordination spheres and do not represent a general methodology. In this work, we present standard reduction potential calculations for copper complexes in aqueous solution covering a wide range of coordination spheres. These calculations were performed using the M06-2X density functional, and by employing the direct and isodesmic approaches. Result analysis reveals that values obtained with the use of the isodesmic method are in better agreement with experimental values than those obtained from the direct method (mean unsigned error 0.39 V with the direct and 0.08 V with the isodesmic method). This approach provides values with errors comparable to the experimental uncertainty due to the proper cancellation of computational errors. These results strongly suggest the isodesmic approach as an adequate methodology for the calculation of SRPs for copper complexes with diverse coordination spheres. Graphical Abstract Comparison between direct and isodesmic methods in the calculation of standard reduction potentials for copper complexes using DFT methods.

A computational protocol for the calculation of the standard reduction potential of iron complexes: application to Fe2+/3+-Aβ model systems relevant to Alzheimer's disease

“…The isodesmic method have been used to calculate SRP and p K a of cobalt complexes. 38,39 Later on Chaparro and Alí-Torres 40 showed a good correlation between the experimental and calculated SRP values in a series of 64 copper complexes using the isodesmic method. The advantage of this methodology is the cancelation of errors in the calculation of solvation Gibbs energies.…”

Role of Metal Cations of Copper, Iron, and Aluminum and Multifunctional Ligands in Alzheimer’s Disease: Experimental and Computational Insights

“…In these terms, antioxidant molecules would be able to disrupt ROS generation thanks to their larger associated SRP value, whereas redistributor-like compounds would exhibit the characteristics needed to accomplish a mechanism for metal redistribution into neuronal cells. These SRP calculations were performed by using an adapted methodology for isodesmic reactions that allows for an accurate prediction, as it was evaluated with a wide variety of copper complexes with different types of coordination spheres . Finally, molecular scaffolds with the desired properties were obtained and used to build up a set of derivatives that fulfill the previous requirements.…”

“…These SRP calculations were performed by using an adapted methodology for isodesmic reactions that allows for an accurate prediction, as it was evaluated with a wide variety of copper complexes with different types of coordination spheres. 173 Finally, molecular scaffolds with the desired properties were obtained and used to build up a set of derivatives that fulfill the previous requirements.…”