Dinitrogen (N2) activation is particularly challenging under ambient conditions because of its large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap (10.8 eV) and high bond dissociation energy (945 kJ mol–1) of the NΞN triple bond, attracting considerable attention from both experimental and theoretical chemists. However, most effort has focused on metallic systems. In contrast, nitrogen activation by frustrated Lewis pairs (FLPs) has been initiated recently via theoretical calculations.

Isotopic oxygen exchange (IOE) is a crucial reaction required in the purification of 238PuO2 which has been used as an important fuel in space exploration. Experimental studies on the IOE between 238PuO2 and O2 are costly and hazardous due to the radioactivity. With extremely similar crystal structures, CeO2 could be a fair surrogate for 238PuO2 in the investigation of physicochemical properties. Here, we perform density functional theory calculations to simulate the IOE between CeO2 and O2, wherein a heteroexchange mechanism is proposed.

In textbooks, the low reactivity of amides is attributed to the strong resonance stability. However, Garg and co-workers recently reported the Ni-catalyzed activation of robust amide C–N bonds, leading to conversions of amides into esters, ketones, and other amides with high selectivity. Among them, the Ni-catalyzed Suzuki-Miyaura coupling (SMC) of N-benzyl-N-tert-butoxycarbonyl (N-Bn-N-Boc) amides with pinacolatoboronate (PhBpin) was performed in the presence of K3PO4 and water. Water significantly enhanced the reaction.

Recent progress in frustrated Lewis pairs (FLPs) has attracted increasing attention. However, most of the FLPs are composed of Lewis basic phosphines and Lewis acidic boranes. In 2015, Kinjo and co-workers reported the first intramolecular boron–boron FLP, namely, 1,3,2,5-diazadiborinine (1), which showed high regioselectivity in the reactions with methyl trifluoromethansulfonate, phenylacetylene, and CO2. More interestingly, the activation of CO2 was found to be reversible when the temperature was elevated to 90 °C.

The synthesis of small cyclic metal carbynes is challenging due to the large angle strain associated with the highly distorted nonlinear triple bonds. Herein, we report a general route for the synthesis of five-membered cyclic metal carbyne complexes, osmapentalynes, by the reactions of an osmapentalene derivative with allene, alkyne, and alkene. Experimental observations and theoretical calculations document the aromaticity in the fused five-membered rings of osmapentalynes.

In general, aromaticity can be clarified as π- and σ-aromaticity according to the type of electrons with major contributions. The traditional π-aromaticity generally describes the π-conjugation in fully unsaturated rings whereas σ-aromaticity may stabilize fully saturated rings with delocalization caused by σ-electron conjugation. Reported herein is an example of σ-aromaticity in an unsaturated three-membered ring (3 MR), which is supported by experimental observations and theoretical calculations.

Treatment of ruthenabenzene [(C9H6NO)Ru{CC(PPh3)CHC(PPh3)CH}(C9H6NO)(PPh3)]Cl2 (1) with NaBH4 produces the first ruthenacyclohexa-1,4-diene [(C9H6NO)Ru{CC(PPh3)CH2C(PPh3)CH}(C9H6NO)(PPh3)]Cl (2), which was fully characterized. Under an oxygen atmosphere, complex 2 can easily convert to complex 1. DFT calculations were carried out to rationalize the high regioselectivity in the reaction of the ruthenabenene 1 with NaBH4 and the interconversion between 1 and 2.

Density functional theory (DFT) calculations were carried out to investigate the [2+2], [3+2] and [4+2] cycloadditions of the phosphaethynolate anion (PCO−). The results reveal that the electronic properties of different unsaturated compounds play a crucial role in reactivity and regioselectivity.

http://pubs.rsc.org/en/Content/ArticleLanding/2014/CC/C4CC04610B#!divAbstract

The reaction mechanism of copper-catalyzed phosphorylation of terminal alkynes under different conditions has been investigated experimentally and theoretically. The important role of dioxygen has been elucidated, including the formation of η1-superoxocopper(II), η2-superoxocopper(III), μ-η2:η2-peroxodicopper(II), and bis(μ-oxo)dicopper(III) complexes.