Diverse Reactions of Nitroxide‐Radical Adducts of Silylene, Germylene, and Stannylene

Iwamoto, Takeaki; Masuda, Hidenori; Ishida, Shintaro; Kabuto, Chizuko; Kira, Mitsuo

doi:10.1002/chin.200426145

Cited by 2 publications

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“…Digoldgermanes 3 were synthesized by the reduction of 2 obtained by the insertion of stable dialkylgermylene 1 [42][43][44][45] into Cl-Au bond of R 3 PAuCl (Scheme 1). Compounds 3 are unique with the two gold atoms heterolytically coordinated by dialkylgermylene 1 and a trialkylphosphine.…”

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confidence: 99%

Unique Digoldgermanes: Structural Characteristics, Dynamic Behaviour and Distinctive Reactions

Wang

Zhen

et al. 2021

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Digoldgermanes with a gold coordinated by a dialkylgermylene ligand, R’2Ge(AuPR3)(AuGeR’2) (3a; R = Me, 3b; R = Et), were synthesized as green solids through the reactions of stable dialkylgermylene 1 with R3PAuCl followed by the reduction with KC8 at ambient temperatures. The structural characteristics of 3a and 3b were elucidated using NMR spectroscopy, X-ray crystallography, and DFT calculations. An intense absorption maximum was observed at 590 nm in the UV-vis spectrum of 3a in hexane. A pendular motion of AuPR3 group between Ge(IV) and Ge(II) of 3a and 3b occurring in the NMR time scale was found by the dynamic 1H NMR analysis, suggesting that the Ge(II) ligand has an enhanced electrophilicity to be attacked by the nucleophilic gold atom which closes to ‒1 oxidation state. DFT calculations of 3a revealed the existence of high-lying σ(Ge-Au) type HOMO and low-lying LUMO with germylene pπ nature. We show the bond formation and activation alternatively at Au or Ge atom, a methylation of digoldgermane 3a with MeOTf affords methylgermane 5. Moreover, the digoldgermane 3a reacts with Cl− ion of Ph4PCl and CH3C(O)Cl smoothly to form the corresponding chloride-addition product 7 and chlorogoldgermane 9, respectively. Cyclic trimerization reactions of aromatic isocyanates were high-efficiently catalyzed by 3a giving the corresponding 1,3,5-triaryl isocyanurates.

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confidence: 99%

Unique Digoldgermanes: Structural Characteristics, Dynamic Behaviour and Distinctive Reactions

Wang

Zhen

et al. 2021

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“…ToF-SIMS measurements further underpin the XPS results as depicted in Figure3(right-hand side). While both the blank and control sample (not displayed) do not show any poly(n-butyl acrylate) fragments, NMRC-functionalized substrate 5 shows both characteristic poly(n-butyl acrylate) signals C 4 H 7 O − and C 4 H 9 O − and nitroxide derivative C 2 H 4 NO − .Degrafting experiments (6) reduced the surface coverage with carbon in XPS from 36 to 20 atom % yet again left some tin compounds behind which are known to add to nitroxide radicals 68. Surprisingly, XPS showed again the removal of most of the OC−O species and hence of the poly(n-butyl acrylate).…”

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Reversible Surface Engineering via Nitrone-Mediated Radical Coupling

et al. 2018

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Efficient and simple polymer conjugation reactions are critical for introducing functionalities on surfaces. For polymer surface grafting, postpolymerization modifications are often required, which can impose a significant synthetic hurdle. Here, we report two strategies that allow for reversible surface engineering via nitrone-mediated radical coupling (NMRC). Macroradicals stemming from the activation of polymers generated by copper-mediated radical polymerization are grafted via radical trapping with a surface-immobilized nitrone or a solution-borne nitrone. Since the product of NMRC coupling features an alkoxyamine linker, the grafting reactions can be reversed or chain insertions can be performed via nitroxide-mediated polymerization (NMP). Poly( n-butyl acrylate) ( M = 1570 g·mol, D̵ = 1.12) with a bromine terminus was reversibly grafted to planar silicon substrates or silica nanoparticles as successfully evidenced via X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry, and grazing angle attenuated total reflection Fourier-transform infrared spectroscopy (GAATR-FTIR). NMP chain insertions of styrene are evidenced via GAATR-FTIR. On silica nanoparticles, an NMRC grafting density of close to 0.21 chains per nm was determined by dynamic light scattering and thermogravimetric analysis. Concomitantly, a simple way to decorate particles with nitroxide radicals with precise control over the radical concentration is introduced. Silica microparticles and zinc oxide, barium titanate, and silicon nanoparticles were successfully functionalized.

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Diverse Reactions of Nitroxide‐Radical Adducts of Silylene, Germylene, and Stannylene

Abstract: For Abstract see ChemInform Abstract in Full Text.

Cited by 2 publications

References 1 publication

Unique Digoldgermanes: Structural Characteristics, Dynamic Behaviour and Distinctive Reactions

Unique Digoldgermanes: Structural Characteristics, Dynamic Behaviour and Distinctive Reactions

Reversible Surface Engineering via Nitrone-Mediated Radical Coupling

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