Use of the 2,6-Bis[(dimethylamino)methyl]phenyl Ligand for the Study of Nucleophilic Substitution at Hexacoordinate Silicon Centers. Evidence Suggestive of a Heptacoordinate Silicon Transition State

Carré, Françis; Chuit, C.; Corriu, Robert J. P.; Fanta, Alan D.; Mehdi, Ahmad; Reyé, Catherine

doi:10.1021/om00001a030

Cited by 49 publications

(24 citation statements)

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“…On the other side, the solubility and the nature of the hybrid molecule were limiting factors. For example, at the same 40 mM molar concentration, bis‐silylated collagen‐like peptide could not reach gelation compared to bis‐silylated PEG 2000 …”

Section: Resultsmentioning

confidence: 99%

“…This was most likely due to working at physiological pH, and to the weak basic properties of glycine. Thus, we hypothesized that silicon was first activated by fluoride, yielding a pentacoordinated silicon intermediate . Then, glycine might further complex the silicon yielding an heptacoordinate species thanks to the silicon ability to make up seven bonds.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, glycine is an additive in our case, with lower concentrations, just helping the sodium fluoride in its regular mechanism, catalysing both hydrolysis and condensation by coordination into silicon atom with both sides of the zwitterionic form. Our proposition is based on the high ability of the silicon atom to extend his coordination number in presence of nucleophilic species …”

Section: Resultsmentioning

confidence: 99%

“…Thus, we hypothesized that silicon was first activated by fluoride, yielding a pentacoordinated silicon intermediate. [48] Then, glycine might further complex the silicon yielding an heptacoordinate species thanks to the silicon ability to make up seven bonds. The zwitterion form of glycine (pKa = 2.3 for the carboxylic acid and 9.6 for the amine) could then form a five-atoms pseudo cycle upon elimination of ethanol (Scheme 3).…”

Section: Proposed Mechanism For Naf + Glycine Catalysismentioning

confidence: 99%

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Biocompatible Glycine‐Assisted Catalysis of the Sol‐Gel Process: Development of Cell‐Embedded Hydrogels

et al. 2019

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The sol‐gel process can be used for hydrogel cross‐linking, thus opening an attractive route for the design of biocompatible hydrogels under soft conditions. The sol‐gel process can be catalysed at basic or acidic pH values, under neutral conditions with the addition of a nucleophile. Therefore, working around pH 7 unlocks the possibility of direct cell embedment and the preparation of bioinks. We aimed to propose a generic method for sol‐gel 3D bioprinting, and first screened different nucleophilic catalysts using bis‐silylated polyethylene glycol (PEG) as a model hydrogel. A synergistic effect of glycine and NaF, used in low concentrations to avoid any toxicity, was observed. Biocompatibility of the approach was demonstrated by embedding primary mouse mesenchymal stem cells. The measure of viscosity as a function of time showed the impact of reaction parameters, such as temperature, complexity of the medium, pH and cell addition, on the kinetics of the sol‐gel process, and allowed prediction of the gelation time.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Proposed Mechanism For Naf + Glycine Catalysismentioning

confidence: 99%

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Biocompatible Glycine‐Assisted Catalysis of the Sol‐Gel Process: Development of Cell‐Embedded Hydrogels

et al. 2019

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“…For bond lengths and angles, as well as data acquisition details see ESI † (Table S2, octacoordination with a tetrahedral SiN 4 core and four oxygen atoms in the "outer sphere", capping the tetrahedral planes. [43][44][45] The chemical shift of the 29 Si NMR signals of monomer 1 in solid state and solution state are similar which indicates the same bonding motif (Fig. S3 in ESI †).…”

Section: Synthesis Of Hybrid Materialsmentioning

confidence: 75%

Polyamide 6/silica hybrid materials by a coupled polymerization reaction

et al. 2015

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Polyamide 6/SiO2 hybrid materials were produced by a coupled polymerization reaction of three monomeric components namely 1,1',1'',1'''-silanetetrayltetrakis-(azepan-2-one) (Si(ε-CL)4), 6-aminocaproic acid (ε-ACA) and ε-caprolactam (ε-CL) within one process. Si(ε-CL)4 together with ε-ACA has been found suitable as precursor monomer for the silica and PA6 component. The accurate adjusting of the molar ratio of both components, as well as the combination of the overall process for producing the polyamide 6/SiO2 hybrid material with the hydrolytic ring opening polymerization of ε-caprolactam is of great importance to achieve homogeneous products with a low extractable content. Water in comparison to ε-ACA has been found unsuitable as oxygen source to produce uniformly distributed silica. The procedure was carried out in a commercial laboratory autoclave at 8 bar initial pressure. The molecular structure and morphology of the hybrid materials have been investigated by solid state 29 Si and 13 C NMR spectroscopy, DSC, FTIR spectroscopy and electron microscopic measurements.

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Some Silatetraazaspiroalkanes with [4 + 4] Octacoordinated Silicon

Rong

Keese²,

Stœckli-Evans

1998

Eur. J. Inorg. Chem.

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Spirocyclic compounds containing an Si(N)4 core have been prepared from 1,2‐ethane‐ and 1,3 propanediamines bearing the electron‐withdrawing p‐toluenesulfonyl groups at the four N atoms. According to the X‐ray structure analysis of the compounds 8a and 13, the spirocyclic rings are almost perpendicular to each other. In both cases a distorted dodecahedral arrangement of a [4 + 4] octacoordinate Si atom is found in which one O atom of each of the four sulfonyl groups caps one of the planes defined by the Si(N)4 tetrahedron. The O···Si distances are 2.85–3.02 Å and the two O···Si···O angles are 145–159°. According to the X‐ray structure analysis of the monocyclic compound 16, one O atom of the p‐toluenesulfonyl group caps the plane defined by O1–N2–C13 of the distorted S(N2)(O)C tetrahedron.

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Use of the 2,6-Bis[(dimethylamino)methyl]phenyl Ligand for the Study of Nucleophilic Substitution at Hexacoordinate Silicon Centers. Evidence Suggestive of a Heptacoordinate Silicon Transition State

Cited by 49 publications

References 0 publications

Biocompatible Glycine‐Assisted Catalysis of the Sol‐Gel Process: Development of Cell‐Embedded Hydrogels

Biocompatible Glycine‐Assisted Catalysis of the Sol‐Gel Process: Development of Cell‐Embedded Hydrogels

Polyamide 6/silica hybrid materials by a coupled polymerization reaction

Some Silatetraazaspiroalkanes with [4 + 4] Octacoordinated Silicon

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