Density Functional Theory (DFT) as a Nondestructive Probe in the Field of Art Conservation: Small-Molecule Adsorption on Aragonite Surfaces.

Humans have incorporated minerals in objects of cultural heritage importance for millennia. The surfaces of these objects, which often long outlast the humans that create them, are undeniably exposed to a diverse mixture of chemicals throughout their lifetimes. As of yet, the art conservation community lacks a nondestructive, accurate, and inexpensive flexible computational screening method to evaluate the potential impact of chemicals with art, as a complement to experimental studies.

Understanding the Individual and Combined Effects of Solvent and Lewis Acid on CO Insertion into a Metal Hydride.

The insertion of CO into a metal hydride bond to form a metal formate is a key elementary step in many catalytic cycles for CO conversion. Similarly, the microscopic reverse reaction, the decarboxylation of a metal formate to form a metal hydride and CO, is important in both organic synthesis and strategies for hydrogen storage using organic liquids. There are however few experimental studies probing the mechanism of these reactions and identifying the effects of specific variables such as Lewis acid (LA) additives or solvent, which have been shown to significantly impact catalytic performance.

Acceleration of CO insertion into metal hydrides: ligand, Lewis acid, and solvent effects on reaction kinetics.

The insertion of CO into metal hydrides and the microscopic reverse decarboxylation of metal formates are important elementary steps in catalytic cycles for both CO hydrogenation to formic acid and methanol as well as formic acid and methanol dehydrogenation. Here, we use rapid mixing stopped-flow techniques to study the kinetics and mechanism of CO insertion into transition metal hydrides. The investigation finds that the most effective method to accelerate the rate of CO insertion into a metal hydride can be dependent on the nature of the rate-determining transition state (TS).

Carbon Dioxide Insertion into Group 9 and 10 Metal-Element σ Bonds.

Carbon dioxide (CO) is an appealing feedstock for the sustainable preparation of a variety of carbon-based commodity chemicals because of its high abundance, low cost, and nontoxicity. The high kinetic and thermodynamic stability of CO, however, means that there are currently only a limited number of practical catalytic systems for the conversion of CO into more valuable chemicals, and continued research in this area is required. One promising approach for the eventual transformation of CO is to initially insert the molecule into transition-metal-element σ bonds such as M-H, M-OR, M-NR, and M-CR bonds to form products of the type M-OC(O)E (E = H, OR, NR, or CR).

Automated method for determining the flow of surface functionalized nanoparticles through a hydraulically fractured mineral formation using plasmonic silver nanoparticles.

Quantifying nanoparticle (NP) transport within porous geological media is imperative in the design of tracers and sensors to monitor the environmental impact of hydraulic fracturing that has seen increasing concern over recent years, in particular the potential pollution and contamination of aquifers. The surface chemistry of a NP defining many of its solubility and transport properties means that there is a wide range of functionality that it is desirable to screen for optimum transport. Most prior transport methods are limited in determining if significant adsorption occurs of a NP over a limited column distance, however, translating this to effects over large distances is difficult.