Reactivity of silagermenylidene toward nitrous oxide: a preliminary DFT study

Abstract

The possible reaction mechanism of silagermenylidene and its NHC (N-heterocyclic carbene) coordinated form with NO were investigated by DFT methods. Mainly, the potential energy surfaces of the five pathways I-IV were explored. Pathways I, II, III, and III' deal with the oxidation of silagermenylidene, whereas that of NHC coordinated form is associated with pathways I, III, III', and IV. Pathway I is initiated by the interaction between terminal N atom of NO and Si atom of silagermenylidene in a stepwise manner. Pathway II details concerted direct oxidation of silagermenylidene. Pathways III and III' are related to the concerted 1,3-dipolar cycloaddition steps. Pathway IV is about the interaction of terminal atoms of NO with carbenic Ge atom of silagermenylidene. All the proposed pathways I-IV portray the isomerization of silagermenylidenes to silagermoxiranylidenes. The subsequent NO addition to the silagermoxiranylidenes was also investigated in the present study. Somehow with a trend similar to silagermenylidenes, the proposed pathways I-IV exist for the second molecule NO activation by silagermoxiranylidenes. A comparison of the free energy profiles of the proposed pathways gave the important result that pathways III and III' remain the most facile mechanisms to activate NO in all cases. We strongly believe that the proposed mechanisms will be effective to better understand the chemistry of heavier vinylidenes and provide further impetus to this field. Graphical Abstract The possible oxidation reaction mechanism of silagermenylidene with nitrous oxide was investigatedthrough density functional calculations. The concerted 1,3-dipolar cycloadditions are determined to beenergetically most facile pathways.

CO2 trapping of selected N‐heterocyclic vinylidenes with an NBO mechanistic scrutiny by DFT

“…[5,6] There is still a growing interest in the characterization of their chemistry, structure, and reactivity. [7] In contrast to covalent interactions, the non-covalent ones are complex. Thus, there is a great interest in the theoretical investigation of systems containing the latter.…”

Synthesis of an NHC-Coordinated Dialkyldisilavinylidene and Its Oxidation Providing a Silicon Analog of an Acetolactone

“…As 1 possesses the SiSi double bond and the tetrylene moiety, 1 should be a precursor for an unprecedented disilicon analog of an acetolactone via the oxidation of the SiSi double bond and the tetrylene providing a disilaepoxide and a SiO bond, respectively. ,,,, Treatment of a powder of 1 with an excess amount of N 2 O gas for 5 h followed by B­(C 6 F 5 ) 3 in benzene afforded disilaacetolactone 4 coordinated by I t Bu and B­(C 6 F 5 ) 3 in 33% yield (Scheme ). , Product 4 was characterized by a combination of multinuclear NMR spectroscopy, HRMS, EA, and XRD analysis (Figure ). To the best of our knowledge, this reaction represents the first example of a reaction of a disilavinylidene.…”

A theoretical investigation on the activation of small molecules by a disilenide: aDFT prediction

“…57 In a very recent study, we proposed several pathways for the activation of N 2 O by silagermenylidene and the concerted 1,3-dipolar cycloaddition fashion is determined to be more operative than others. 58,59 Inspired by this, the concerted 1,3-dipolar cycloaddition mechanism via TS1 −N 2 O and its vice versa fashion (TS1 ′ −N 2 O) were considered in this part due to lower energy barriers ( Figure 8). The activation energy barriers are found to be almost identical for TS1 −N 2 O ( ∆G ̸ = = 9.8 kcal mol −1 ) and TS1 ′ −N 2 O ( ∆ G ̸ = = 9.9 kcal mol −1 ), and closely resemble the calculated initial energy barrier for the CO activation process ( ∆ G ̸ = = 9.4 kcal mol −1 ) .…”