Homogeneous Molecular Systems Research Articles

Electrocatalytic reduction of CO2 to CO by Fe(iii) carbazole–porphyrins in homogeneous molecular systems

Iron porphyrin can electrocatalytically reduce CO2 to CO by applying a voltage in a homogeneous solution.

Electroreduction of CO2 Catalyzed by Nickel Imidazolin-2-ylidenamino-Porphyrins in Both Heterogeneous and Homogeneous Molecular Systems

Electrocatalytic carbon dioxide reduction to value-added chemicals is an important strategy to store renewable energy. Despite recent advances, the current level of performance of these systems doe...

Mixed Molecular Electronics: Tunneling Behaviors and Applications of Mixed Self‐Assembled Monolayers

AbstractMolecular electronics promise electronic devices that are miniaturized to molecular and atomic levels. Despite significant efforts made towards understanding and improving the electronic functions of devices based on homogeneous molecular systems, the roles, effects, and importance of molecular‐level dilution and mixing in active components for device performance have only recently begun to be understood. Recent advances in molecular electronics based on heterogeneous active components, defined as mixed molecular electronics, are reviewed, with a particular focus on molecular tunnel junctions containing mixed self‐assembled monolayers (SAMs). Through a stepwise approach, the following is provided: a) a summary of the unique (supra)molecular and electronic structural features of mixed SAMs compared to homogeneous SAMs, b) a discussion on fundamental understanding of charge transport across mixed molecular systems, c) a comprehensive summary of functional mixed‐molecular tunneling devices, and d) perspectives on the future direction of mixed molecular electronics.

In‐Situ Nanostructuring and Stabilization of Polycrystalline Copper by an Organic Salt Additive Promotes Electrocatalytic CO2 Reduction to Ethylene

AbstractBridging homogeneous molecular systems with heterogeneous catalysts is a promising approach for the development of new electrodes, combining the advantages of both approaches. In the context of CO2 electroreduction, molecular enhancement of planar copper electrodes has enabled promising advancement towards high Faradaic efficiencies for multicarbon products. Besides, nanostructured copper electrodes have also demonstrated enhanced performance at comparatively low overpotentials. Herein, we report a novel and convenient method for nanostructuring copper electrodes using N,N′‐ethylene‐phenanthrolinium dibromide as molecular additive. Selectivities up to 70 % for C≥2 products are observed for more than 40 h without significant change in the surface morphology. Mechanistic studies reveal several roles for the organic additive, including: the formation of cube‐like nanostructures by corrosion of the copper surface, the stabilization of these nanostructures during electrocatalysis by formation of a protective organic layer, and the promotion of C≥2 products.

In‐Situ Nanostructuring and Stabilization of Polycrystalline Copper by an Organic Salt Additive Promotes Electrocatalytic CO2 Reduction to Ethylene

Bridging homogeneous molecular systems with heterogeneous catalysts is a promising approach for the development of new electrodes, combining the advantages of both approaches. In the context of CO2 electroreduction, molecular enhancement of planar copper electrodes has enabled promising advancement towards high Faradaic efficiencies for multicarbon products. Besides, nanostructured copper electrodes have also demonstrated enhanced performance at comparatively low overpotentials. Herein, we report a novel and convenient method for nanostructuring copper electrodes using N,N'-ethylene-phenanthrolinium dibromide as molecular additive. Selectivities up to 70 % for C≥2 products are observed for more than 40 h without significant change in the surface morphology. Mechanistic studies reveal several roles for the organic additive, including: the formation of cube-like nanostructures by corrosion of the copper surface, the stabilization of these nanostructures during electrocatalysis by formation of a protective organic layer, and the promotion of C≥2 products.

Homogeneous Molecular Systems are Positively Cooperative, but Charged Molecular Systems are Negatively Cooperative.

Molecular systems bound together through noncovalent interactions are ubiquitous in nature, many of which are involved in essential life processes, yet little is known about the principles governing their structure, stability, and function. Cooperativity as one of the intrinsic properties in these systems plays a key role. In this work, on the basis of our recent quantification scheme of the cooperativity effect, we present a general pattern to identify which systems are positively cooperative and which are negatively cooperative. We show that cooperativity in homogeneous molecular systems is positive, but cooperativity in charged molecular systems is negative. We also employ analytical tools from energetics and information perspectives to appreciate the origin of the cooperativity effect. We find that positive cooperativity is dominated by the exchange-correlation interaction and steric effect, whereas negative cooperativity is governed by the electrostatic interaction. Our results should have strong implications for better understanding molecular recognition, protein folding, signal transduction, allosteric regulation, and other processes.