Isolation and Reactivity of Stannylenoids Stabilized by Amido/Imino Ligands

Abstract

The reaction of the lithium aryl(silyl)amide Dipp(iPr3Si)NLi (Dipp=2,6‐iPr2C6H3) with one equivalent of SnCl2 in THF gave a novel stannylenoid Dipp(iPr3Si)NSnCl⋅LiCl(THF)2. Heating the solution of amidostannylenoid in toluene to 80 °C resulted in dimeric amido(chloro)stannylene [Dipp(iPr3Si)NSnCl]2, which can be converted to bis(amido)stannylene Sn[N(Dipp)(iPr3Si)]2 and amido(imino)stannylene Sn[N(Dipp)(iPr3Si)][IPrN] (IPrN=bis(2,6‐diisopropylphenyl)imidazolin‐2‐imino). Treatment of bis(imino)stannylenoid [IPrN]2Sn(Cl)Li with N2O resulted in the dimeric complex [IPrNSn(Cl)OLi]2. All compounds were characterized by NMR, elementary analysis, and X‐ray structural determination.

Synthesis and isolation of a cyclic bis-vinyl germylene via a diazoolefin adduct of germylene dichloride

“…Recently, structurally related ligands, namely N-heterocyclic imines (NHI), N-heterocyclic olefins (NHO) and N-heterocyclic carbenes (NHC), have been utilised for the isolation of various main group compounds. [10][11][12][13][14][15] For example, several Group 14 [11][12][13][14][15] complexes including the NHC adducts of GeCl 2 16 and SnCl 2 , 17 were successfully isolated thanks to their electron donation capabilities combined with the kinetic stabilization due to the substituents at the nitrogen atom. 18 In addition to this, NHOs also have been proven to be excellent donors in main group chemistry due to their nucleophilic and ylidic character on the exocyclic carbon centre, therefore standing in very close relationship to the recently discovered diazoolefins.…”

“…The 1 H-NMR signals of 3 are highfield shifted up to 0.66 ppm (269 Hz) compared to compound 1. Through HMBC analysis, a severely downfield shifted 13 The SC-XRD structure of 3 (Fig. 2) reveals two Ge-C bonds with lengths of 1.9439(2) Å and 1.9455(2) Å.…”

An Air-Stable “Masked” Bis(imino)carbene: A Carbon-Based Dual Ambiphile

“…N-Heterocyclic imines (NHIs) derived from conventional N-heterocyclic carbenes (NHCs) , are powerful 2σ, 4π electron donor ligands with a large steric profile. NHIs have recently received significant attention due to their ability to stabilize a wide range of highly electron-deficient main group systems. − However, the moderate electrophilic properties of these NHIs limit them to being purely Lewis basic ligands. On the other hand, CAACs have higher nucleophilicity than NHCs, but are immensely more electrophilic, − leading us to believe that an NHI based on a CAAC might be a suitable donor to tame an (imino)­carbene, but at the same time possess sufficient electrophilicity to act as a secondary Lewis acidic site .…”