An electric field-based approach for quantifying effective volumes and radii of chemically affected space

Chemical shape and size play a critical role in chemistry. The van der Waals (vdW) radius, a familiar manifold used to quantify size by assuming overlapping spheres, provides rapid estimates of size in atoms, molecules, and materials. However, the vdW method may be too rigid to describe highly polarized systems and chemical species that stray from spherical atomistic environments. To deal with these exotic chemistries, numerous alternate methods based on electron density have been presented. While each boasts inherent generality, all define the size of a chemical system, in one way or another, by its electron density. Herein, we revisit the longstanding problem of assessing sizes of atoms and molecules, instead through examination of the local electric field produced by them. While conceptually different than nuclei-centered methods like that of van der Waals, the field assesses chemically affected volumes. This approach implicitly accounts for long-range fields in highly polar systems and predicts that cations should affect more space than neutral counterparts.

Computing atomic and molecular volumes from DFT and ab initio-based electric fields.     

Metal-Organic Frameworks for Efficient Electrochemical Reduction of Carbon Dioxide

The large concentration of carbon dioxide (CO₂) in the atmosphere can be utilized in industrial production using effective electrocatalysts such as metal-organic frameworks (MOFs). Due to good properties such as high surface area, designable functionality, and uniform constitution, MOFs are regarded as promising electrocatalysts for the carbon dioxide electrochemical reduction reaction (eCO₂RR). This review covers the importance, challenges, and mechanism of eCO₂RR, and simply discusses the progress in the synthesis methods and characterization of MOFs. The review also thoroughly discusses the advances of single metal-based MOFs, mixed metal-based MOFs, and MOF derivatives as electrocatalysts for efficient eCO₂RR.     

Electrochemical Properties of Ru Polypyridyl Phosphonates

[Ru(bpyPO₃H₂)(bpy)Cl]Cl (bpyPO₃H₂=6,6’-bipyridin-2-yl)phosphonic acid) and [Ru(tpy)(MepyPO₃H₂)Cl]Cl (MepyPO₃H₂=(pyridin-2-ylmethyl)phosphonic acid) were synthesized and characterized spectroscopically and electrochemically. Each compound was found to exhibit proton-coupled electron transfer (PCET). In the case of [Ru(bpyPO₃H₂)(bpy)Cl]Cl, a Ru(V/IV) couple was detected at 1.4 V vs. NHE. Each complex was tested for its ability to catalyze C−H bond oxidation using a variety of sacrificial oxidants, and it was found that under aqueous conditions [Ru(bpyPO₃H₂)(bpy)Cl]Cl oxidizes secondary C−H bonds using sodium periodate (NaIO₄) as the primary oxidant.