Electrochemical synthesis of bis(2-thienyl) silanes, 2-thienylchlorosilanes, bis[5-(2-bromothienyl)]silanes, and 5-(2-bromothienyl) dimethylchlorosilane, precursors of poly[(silanylene)thiophene]s

Moreau, C.; Serein-Spirau, Françoise; Bordeau, M.; Biran, C.; Dunoguès, J.

doi:10.1016/0022-328x(96)06333-4

Cited by 15 publications

(26 citation statements)

References 23 publications

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“…In the literature, usually up to 2.2 F had to be applied to achieve complete conversion of the starting materials, 4-14 although Bordeau et al observed abnormally high anodic faradaic yields (amount of consumed metal compared with charge passed) in the electrolyses of 2-bromothiophene in the presence of Me 2 SiCl 2 when using Mg anodes. They assumed the occurrence of a chemical reduction at the anodically scoured Mg. 12 This is consistent with our results. When using organic bromides we observed that far less than the stoichiometric number of electrons was needed for a complete reaction (compare Tables I and II).…”

Section: Methodssupporting

confidence: 95%

Electrochemical Synthesis of Functional Organosilanes II: Direct Electrochemical Formation of Si-C Bonds

Grogger

Loidl

Stueger

et al. 2013

J. Electrochem. Soc.

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Electroreductive Si-C bond formation was used for the formation of organofunctional silanes of the general formula HMe 2 Si-R-Y and MeOMe 2 Si-R-Y (R = alkylene, arylene; Y = H, MeO, Me 2 N, t-BuMe 2 SiO). Employing constant current conditions, different organic halides R-X (R = alkylene, arylene, X = Cl, Br) were electrolyzed in the presence of Me 2 Si(OMe) 2 and HMe 2 SiCl, respectively. All electrolyses were carried out in an undivided cell and with a THF/LiCl (MgCl 2 ) electrolyte. Although both salts are suitable supporting electrolytes, the highest conductivity was obtained with a mixture of LiCl/MgCl 2 = 2/1. It was shown that the reaction proceeds smoothly at current densities between 0.25 and 35 mA cm −2 . Cooling of the electrolysis cell can be omitted.There exist a variety of methods for silicon-carbon bond formation. Examples include the fundamental industrial Direct Process, Grignard-type processes, Wurtz-Fittig coupling reactions and transition metal-catalyzed reactions. 1 One practical method that can be utilized on the laboratory scale is the electrochemical formation of Si-C bonds, which basically involves the reduction of the organic substrate followed by an attack of the electrogenerated C-nucleophile on the Si-Cl bond of a chlorosilane (Scheme 1).In the early 1980s, Shono et al. 2,3 and Yoshida et al. 4 showed that this kind of electroreductive cross-coupling is possible in a divided cell with Pt anodes, but no defined anodic oxidation products were reported. In the great majority of the following papers reporting electrochemical Si-C bond formation, Me 3 SiCl was used as the silyl source. A variety of organic substrates was used with different experimental setups. [5][6][7][8] When di-, tri-or tetrachlorosilanes were used as the electrophiles in stoichiometric quantities, all chlorine substituents on silicon reacted with the electrochemically generated carbanions, thus yielding the corresponding linear, branched or cyclic Si-C compounds. 9-13 There are only a few examples demonstrating that functionality on the silicon atom can be retained: Yoshida et al. 4 reduced cinnamyl chloride in a divided cell with Pt electrodes in the presence of an excess of HMe 2 SiCl. They obtained a mixture of 1,1 and 1,3 silylation products, thus proving the stability of the Si-H bond under electrochemical conditions (Scheme 2).Bordeau et al. electrolyzed several aryl and heteroaryl bromides in the presence of dichlorosilanes R 2 SiCl 2 in an undivided cell with sacrificial anodes. 14-16 They found that a large excess of chlorosilane, a strongly coordinating co-solvent (mostly hexamethyl phosphoric triamide HMPA) and/or a Ni catalyst, had to be used in order to preserve one of the chloro substituents on silicon (cf. Scheme 3).We have been studying the synthesis of organofunctional silanes (OFS) of the general formula X-(Me 2 )Si-R-Y, where X and Y are reactive functional groups and R = alkylene or arylene. With potentially reactive substituents at both silicon and at carbon, these products are useful reactants i...

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Section: Methodssupporting

confidence: 95%

Electrochemical Synthesis of Functional Organosilanes II: Direct Electrochemical Formation of Si-C Bonds

Grogger

Loidl

Stueger

et al. 2013

J. Electrochem. Soc.

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“…The 1 H NMR spectrum of 3a (Figure ) shows that, in addition to the set of peaks corresponding to the thiophene protons (δ 7.3−7.5), three large separate peaks are apparent at δ 0.33, 0.64, and 0.95. These peaks correspond quite well to the methyl proton chemical shifts in small-molecule model compounds − (Figure ), which in turn correspond to the different types of branch points in the hyperbranched polymer. The branched nature of these polymers was also confirmed by 29 Si NMR spectroscopy, which indicated the presence of the four different types of silicon atoms.…”

Section: Resultssupporting

confidence: 52%

Hyperbranched Poly(2,5-silylthiophenes). The Possibility of σ−π Conjugation in Three Dimensions

Yao

Son

1999

Organometallics

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New hyperbranched organosilicon polymers have been prepared from 2-bromo-5-(trimethoxysilyl)thiophene. The intermediate alkoxy-substituted hyperbranched polymer is functionalized with Grignard reagents in situ, leading to the isolation of a series of air- and moisture-stable polymers. The polymers contain alternating silylene and thiophene groups along the branches and thus afford the possibility of σ−π conjugation in three dimensions. Investigations into the effects of this dimensionality utilize UV−visible spectroscopy.

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“…In a previous work, we found that (Th−) 2 SiR 1 R 2 (Th− = 2-thienyl) and (Br−Th−) 2 SiR 1 R 2 (−Th− = 2,5-thienylene) could be prepared selectively by cathodic reduction of 2,5-dihalothiophenes in the presence of a dichlorosilane. In the present work, the cathodic coupling has been extended successfully to the preparation of longer oligomers of poly[2,5-(silanylene)thiophene]s and of 2,5-bis(chlorosilyl)thiophenes in up to a 5−15 g scale.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Stepwise Synthesis of Poly[2,5-(silanylene)thiophene] Precursors

et al. 1998

Self Cite

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The easy control of the electrochemical parameters involved in the intensiostatic sacrificial anode technique was applied to the stepwise synthesis of silanylene-2,5-thiophenylene backbones with high selectivity and versatility not accessible by purely chemical routes. 2,5-Bis(chlorodiorganosilyl)thiophenes and related linear poly[2,5-(silanylene)thiophene] oligomers with one to three silicon atoms were synthesized by electrochemical reduction of 2,5-dibromo- or 2,5-dichlorothiophene in the presence of a diorganodichlorosilane.

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Electrochemical synthesis of bis(2-thienyl) silanes, 2-thienylchlorosilanes, bis[5-(2-bromothienyl)]silanes, and 5-(2-bromothienyl) dimethylchlorosilane, precursors of poly[(silanylene)thiophene]s

Cited by 15 publications

References 23 publications

Electrochemical Synthesis of Functional Organosilanes II: Direct Electrochemical Formation of Si-C Bonds

Electrochemical Synthesis of Functional Organosilanes II: Direct Electrochemical Formation of Si-C Bonds

Hyperbranched Poly(2,5-silylthiophenes). The Possibility of σ−π Conjugation in Three Dimensions

Electrochemical Stepwise Synthesis of Poly[2,5-(silanylene)thiophene] Precursors

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