Computational Exploration of Mechanistic Avenues in Metal-Free CO2 Reduction to CO by Disilyne Bisphosphine Adduct and Phosphonium Silaylide

Activation of carbon disulfide by a hypersilyl germylene

In this work, the insertion of CS2 into the Ge-Si bond of PhC(NtBu)2Ge-Si(SiMe3)3 (1) has been investigated, resulting in the formation of PhC(NtBu)2Ge-C(S)-S-Si(SiMe3)3 (2). Interestingly, the addition of NHC to 2 allows the release of NHC·CS2 with concomitant regeneration of 1. Addition of another equivalent of 1 or an analogous hypersilyl silylene, [PhC(NtBu)2Si-Si(SiMe3)3], to 2 led to the formation of compounds with a GeS (3) or a SiS (4) bond.

Applications of low-valent compounds with heavy group-14 elements

Over the last two decades, the low-valent compounds of group-14 elements have received significant attention in several fields of chemistry owing to their unique electronic properties. The low-valent group-14 species include tetrylenes, tetryliumylidene, tetrylones, dimetallenes and dimetallynes. These low-valent group-14 species have shown applications in various areas such as organic transformations (hydroboration, cyanosilylation, N-functionalisation of amines, and hydroamination), small molecule activation (e.g. P4, As4, CO2, CO, H2, alkene, and alkyne) and materials. This review presents an in-depth discussion on low-valent group-14 species-catalyzed reactions, including polymerization of rac-lactide, L-lactide, DL-lactide, and caprolactone, followed by their photophysical properties (phosphorescence and fluorescence), thin film deposition (atomic layer deposition and vapor phase deposition), and medicinal applications. This review concisely summarizes current developments of low-valent heavier group-14 compounds, covering synthetic methodologies, structural aspects, and their applications in various fields of chemistry. Finally, their opportunities and challenges are examined and emphasized.

Organoaluminum hydrides catalyzed hydroboration of carbonates, esters, carboxylic acids, and carbon dioxide

The reductive functionalization of the CO unit of carbonates, carboxylic acids, esters, and CO₂, respectively has received great attention since its introduction. This method is often used industrially for the synthesis of high value-added energy products in chemistry. This opens up a new way forward to reduce greenhouse gases and the consumption of traditional energy sources. Herein, we report an earth-abundant, cheap, and readily available aluminum dihydride, which can catalyze the reduction of a range of carbonates, esters, carboxylic acids, and CO₂, respectively in the presence of pinacolborane as a reducing agent. Moreover, we demonstrate that the reaction can proceed to obtain good yield products under mild conditions, with low catalyst loading and solvent-free reactions. The mechanism of the catalytic reduction of carbonates has been investigated.