Cooperative Bond Activation and Catalytic CO2 Functionalization with a Geometrically Constrained Bis(silylene)-Stabilized Borylene

Metal-ligand cooperativity has emerged as an important strategy to tune the reactivity of transition-metal complexes for the catalysis and activation of small molecules. Studies of main-group compounds, however, are scarce. Here, we report the synthesis, structural characterization, and reactivity of a geometrically constrained bis(silylene)-stabilized borylene. The one-pot reaction of [(SiNSi)Li(OEt2)] (SiNSi = 4,5-bis(silylene)-2,7,9,9-tetramethyl-9H-acridin-10-ide) with 1 equiv of [BBr3(SMe2)] in toluene at room temperature followed by reduction with 2 equiv of potassium graphite (KC8) leads to borylene [(SiNSi)B] (1), isolated as blue crystals in 45% yield. X-ray crystallography shows that borylene (1) has a tricoordinate boron center with a distorted T-shaped geometry. Computational studies reveal that the HOMO of 1 represents the lone pair orbital on the boron center and is delocalized over the Si-B-Si unit, while the geometric perturbation significantly increases its energy. Borylene (1) shows single electron transfer reactivity toward tris(pentafluorophenyl)borane (B(C6F5)3), forming a frustrated radical pair [(SiNSi)B]•+[B(C6F5)3]•-, which can be trapped by its reaction with PhSSPh, affording an ion pair [(SiNSi)BSPh][PhSB(C6F5)3] (3). Remarkably, the cooperation between borylene and silylene allows the facile cleavage of the N-H bond of aniline, the P-P bond in white phosphorus, and the C═O bond in ketones and carbon dioxide, thus representing a new type of main-group element-ligand cooperativity for the activation of small molecules. In addition, 1 is a strikingly effective catalyst for carbon dioxide reduction. Computational studies reveal that the cooperation between borylene and silylene plays a key role in the catalytic chemical bond activation process.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:145

Enthalten in:

Journal of the American Chemical Society - 145(2023), 12 vom: 29. März, Seite 7011-7020

Sprache:

Englisch

Beteiligte Personen:

Chen, Xi [VerfasserIn]
Yang, Yin [VerfasserIn]
Wang, Hao [VerfasserIn]
Mo, Zhenbo [VerfasserIn]

Links:

Volltext

Themen:

Journal Article

Anmerkungen:

Date Completed 29.03.2023

Date Revised 29.03.2023

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1021/jacs.3c00949

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM35444686X