Planar Tetracoordinate Silicon in Organic Molecules As Carbenoid‐Type Amphoteric Centers: A Computational Study

Abstract

Designing and synthesizing as table compound with ap lanar tetracoordinate silicon (ptSi)c enteri sachallenginggoal for chemists. Here, as eries of potentiala romatic ptSi compounds composed of four conjugated rings shared by acentrally embedded Si atom are theoretically designed and computationally verified.B oth Born-Oppenheimer molecular dynamics (BOMD) simulations and potential energy surface scannings verify the high stability and likely existence of these compounds, particularly Si-16-5555 (SiN 4 C 8 H 8)w ith 16 p electrons, under standard ambient temperature and pressure.N otably,t he Hückel aromaticity rule, which works well for single rings, is inconsistent with the high stabilityo fS i-16-5555 where the 16 pe lectrons are spreado verf our five-membered rings fused together.B onding analyses show that the strong electron donation from the peripheral1 2-membered conjugated ring with 16 p electrons to the vacant central atomic orbital Si 3p z leads to the stabilization for both the ptSi coordination and planar aromaticity. The partial occupation of Si 3p z resultsi nt he peculiar carbenoid-type behaviors for the amphoteric center. By modulating the electron density on the ring with substituent groups,w ec an regulate the nucleophilic and electrophilic properties of the central Si.

The inversion of tetrahedral p-block element compounds: general trends and the relation to the second-order Jahn–Teller effect

“…1C). 16,17 Strategies to stabilize square planar congurations for some other elements were probed computationally, [18][19][20][21][22][23][24] and substantial progress was made for compounds featuring planar silicon. [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] However, a systematic fundament of the inversion process in ER 4 compounds or more general statements on their tetrahedral preference are elusive.…”

An isolable, crystalline complex of square-planar silicon(IV)

“… 41 , 44 , 45 , 46 More recent computational studies on molecular complexes of ptSi IV even proposed carbenoid character to the square-planar silicon(IV). 47 Ultimately, it is the small HOMO-LUMO gap that renders d-block metals or p-block elements in the low-valence states as suitable for bond activation. 48 Hence, planarization might project those beneficial features to silicon—while staying in the normal oxidation state.…”

Theoretical studies of MXene-supported single-atom catalysts: Os1/Ti2CS2 for low-temperature CO oxidation

“…Over the past decade, SAC has expanded rapidly and the concept of SAC has been further developed into dynamic SACs [24] and single-cluster catalysts (SCCs) [25,26]. Many studies [27][28][29][30][31][32][33][34][35][36] have been devoted to obtaining SACs with high stability, high selectivity and high reactivity [37][38][39] for thermocatalysis, photocatalysis, electrocatalysis, and photoelectrocatalysis reactions [15,[40][41][42][43], such as CO oxidation, water gas shift reaction, activation of C-H bonds, photo-and electro-catalytic water splitting, and CO 2 reduction reaction, oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, hydrogenation reactions, and nitrogen reduction reaction [5,15,[43][44][45][46][47][48][49][50][51][52][53][54].…”