A new highly efficient method for the preparation of phenyl-containing siloxanes by condensation of phenylsilanols in liquid ammonia

Ershova, Tatyana O.; Анисимов, А. А.; Krylov, Fedor; Polshchikova, N. V.; Temnikov, Maxim N.; Shchegolikhina, Olga I.; Музафаров, А. М.

doi:10.1016/j.ces.2021.116916

Cited by 10 publications

(9 citation statements)

References 33 publications

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“…Cyclosiloxanes are generally prepared from the corresponding dichlorosilanes or silanediols in highly acidic or basic conditions, in which the Si–C bond of polycyclic aromatic hydrocarbon is labile in these conditions . Recently, highly effective condensation of phenylsilanol derivatives in liquid ammonia has been reported . During our study on anion recognition chemistry with silanols, we reported that 1,1,3,3-tetraphenyl-1,3-disiloxane-1,3-diols were smoothly condensed to form the corresponding hexaphenylcyclotrisiloxane and octaphenylcyclotetrasiloxane in the presence of acetate anion as a weak base in polar organic solvents such as acetonitrile within 1 h; however, the same reaction was dramatically slow (over 72 h) in apolar organic solvents such as chloroform .…”

Section: Introductionmentioning

confidence: 95%

“…13 Recently, highly effective condensation of phenylsilanol derivatives in liquid ammonia has been reported. 14 During our study on anion recognition chemistry with silanols, we reported that 1,1,3,3tetraphenyl-1,3-disiloxane-1,3-diols were smoothly condensed to form the corresponding hexaphenylcyclotrisiloxane and octaphenylcyclotetrasiloxane in the presence of acetate anion as a weak base in polar organic solvents such as acetonitrile within 1 h; however, the same reaction was dramatically slow (over 72 h) in apolar organic solvents such as chloroform. 15 Acetate anion may activate the nucleophilicity of the Si−OH group as a general base and the polar pentavalent intermediate and/or the transition state on the substitution were stabilized in such polar organic solvents.…”

Section: ■ Introductionmentioning

confidence: 99%

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Synthesis and Characterization of Cyclotri- and Tetrasiloxanes with Pyrenyl Groups

et al. 2022

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Cyclosiloxanes directly bearing polyaromatic groups on silicon atoms have scarcely been reported. Herein, hexa(1pyrenyl)cyclotrisiloxane (2) and octa(1-pyrenyl)cyclotetrasiloxane (3) were successfully prepared from di(1-pyrenyl)silanediol (1) in the presence of a weak base such as tetraethylammonium acetate and triethylamine in MeCN. The structure of the cyclosiloxanes bearing multiple pyrenyl groups in the solid and solution states was evaluated by NMR, X-ray crystallography, and density functional theory (DFT) calculations. All pyrenyl groups of 2 were oriented outward, and no π−π stacking of adjacent pyrenyl groups was observed. However, all pairs of adjacent pyrenyl groups at 1-and 3-positions in 3 are oriented in the same direction and were π−π stacked with respect to each other. The UV−vis spectra of 2 and 3 in organic solvents showed a slight broadening of the peaks, as observed for typical pyrene derivatives. Interestingly, the fluorescence spectra of 2 showed small monomer and strong excimer emissions; however, those of 3 showed only a strong excimer emission in all solvents. Partially pyrenylated cyclotri-and tetrasiloxanes (compounds 4 and 5) showed solvent-dependent monomer and excimer spectra as observed for di(1-pyrenyl)silane derivatives, implying that the excimer emissions of 2 and 3 arise from mainly geminal and vicinal pyrenyl groups, respectively.

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Section: Introductionmentioning

confidence: 95%

Section: ■ Introductionmentioning

confidence: 99%

Synthesis and Characterization of Cyclotri- and Tetrasiloxanes with Pyrenyl Groups

et al. 2022

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“…Previously, we demonstrated the effectiveness of a similar approach to the condensation of phenylsilanols. − Here, we report our research on water-initiated anionic polymerization of hexamethylcyclotrisiloxane (D 3 Me2 ).…”

Section: Introductionmentioning

confidence: 97%

Low Dispersity Telechelic Polydimethylsiloxanes Synthesized in Ammonia Medium

Minyaylo

Temnikov

Анисимов

et al. 2022

ACS Appl. Polym. Mater.

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The polymerization of hexamethylcyclotrisiloxane (D 3 Me2 ) in liquid ammonia using water as an initiator has been studied. These polymers are of practical importance for a wide range of applications in the silicone industry. The effect of factors such as temperature, reaction time, and concentration of reactants on the polymerization process was evaluated. As a result, an environmentally friendly procedure for the preparation of narrowly dispersed telechelic polydimethylsiloxanes (Mn = 8.0 kDa, PDI = 1.11) with a monomer conversion of up to 98% was developed. The possibility of scaling up the process and recycling of ammonia was shown.

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“…First, the pendant group chemistry may be altered from the dimethyl groups of polydimethylsiloxane (PDMS), the most widespread type of silicone. For instance, diphenyl silicones exhibit improved optical properties and thermal stability . Second, cross-linking density, afforded by terminal or pendant reactive groups, can also be used to tailor mechanical properties .…”

Section: Introductionmentioning

confidence: 99%

Biomedical Silicones: Leveraging Additive Strategies to Propel Modern Utility

Marmo

Grunlan

2023

ACS Macro Lett.

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Silicones have a long history of use in biomedical devices, with unique properties stemming from the siloxane (Si–O–Si) backbone that feature a high degree of flexibility and chemical stability. However, surface, rheological, mechanical, and electrical properties of silicones can limit their utility. Successful modification of silicones to address these limitations could lead to superior and new biomedical devices. Toward improving such properties, recent additive strategies have been leveraged to modify biomedical silicones and are highlighted herein.

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A new highly efficient method for the preparation of phenyl-containing siloxanes by condensation of phenylsilanols in liquid ammonia

Cited by 10 publications

References 33 publications

Synthesis and Characterization of Cyclotri- and Tetrasiloxanes with Pyrenyl Groups

Synthesis and Characterization of Cyclotri- and Tetrasiloxanes with Pyrenyl Groups

Low Dispersity Telechelic Polydimethylsiloxanes Synthesized in Ammonia Medium

Biomedical Silicones: Leveraging Additive Strategies to Propel Modern Utility

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