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Upstream product

• 18620-02-5 (4-bromophenyl)magnesium bromide 
• 75-78-5 dimethylsilicon dichloride 
• 22480-64-4 4-bromophenyllithium 
• 106-37-6 1.4-dibromobenzene 

Downstream Products

• 18106-46-2 1,3-bis(4′-bromophenyl)-1,1,3,3-tetramethyldisiloxane 
• 67347-09-5 N-(p-Bromphenyldimethylsilyl)-acetamid 
• 18246-02-1 (4-bromophenyl)dimethylsilanol 
• 83838-01-1 (4-bromophenyl)dimethyl(ethynyl)silane 
• 468732-12-9 (R,S)-2-(N,N-dimethylaminomethyl)ferrocenyl(4-bromophenyl)dimethylsilane 
• 1178886-55-9 Si(C₆H₄Si(CH₃)2(CH₂CHCH₂))4 
• 17983-33-4 1-allyldimethylsilyl-4-bromobenzene 
• 18537-19-4 4,4'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)dibenzonitrile 
• 18054-10-9 4,4'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)dibenzoic acid 
• 17994-95-5 Pentamethyl-<4-brom-phenyl>-disiloxan 

Relevant academic research and scientific papers

Enantioselective 1,2-Anionotropic Rearrangement of Acylsilane through a Bisguanidinium Silicate Ion Pair

Highly enantioselective bisguanidinium-catalyzed tandem rearrangements of acylsilanes are reported. The acylsilanes were activated via an addition of fluoride on the silicon to form a penta-coordinate anionic silicate intermediate. The silicate then underwent alkyl or aryl group migration from the silicon atom to the neighboring carbonyl carbon atom (1,2-anionotropic rearrangement), followed by [1,2]-Brook rearrangement to provide the secondary alcohols in high yields with excellent enantioselectivities (up to 95% ee). The isolation of an α-silylcarbinol intermediate as well as DFT calculations revealed that the 1,2-anionotropic rearrangement occurred via a bisguanidinium silicate ion pair, which is the stereodetermining step. The chiral center formed is then retained without inversion through the subsequent [1,2]-Brook rearrangement. Crotyl acylsilanes were smoothly transformed into homoallylic linear crotyl alcohols with retention of E/Z geometry, and no branched alcohols were detected. This clearly suggested that the 1,2-anionotropic rearrangement occurred through a three-membered instead of a five-membered transition state.

Allyl-end-grafted carbosilane dendrimers based on 1,4-phenylene units: Synthesis, reactivity, structure, and bonding motifs

The synthesis of a series of carbosilanes of type 1-Br-C6H 4-4-SiMe3-n(CH2CH=CH2)n (n = 1, 2, 3), Si[C6H4-4-SiMe3-n(CH 2CH=CH2)n

Preparation, characterization and properties of dipolar 1,2-N,N-dimethylaminomethylferrocenylsilanes

A series of substituted 1,2-N,N-dimethylaminomethlyferrocenyl compounds were synthesized and characterized by 1H-NMR, 13C-NMR, 29Si-NMR, ES-MS, IR, UV - vis and 57Fe-M?ssbauer spectroscopy. The new (R,S)-2-(N,N-dimethylaminomethyl)ferrocenyl-(arly)silanes (R,S)-FcNSiMen(C6H4X)m (n = 2-0, m = 1, X = p-F (5); m = 2, X = p-F (6); m = 3, X = p-F (7) and m = 1, X = p-Br (14) were formed by the reaction of 2-dimethylaminomethylferrocenyllithium FcNLi (1) with chloroarylsilanes ClSi(Me)n (C6H4X)m (n = 2-0, m = 1, X = p-F (2); m = 2, X = p-F (3); m = 3, X = p-F (4) and m = 1, X = p-Br (13)). The treatment of 5, 6 and 14 with gaseous hydrogen chloride or picric acid resulted in the formation of the hydrochloride complexes 9, 10, 15 and the picrates 11, 12 and 16. The treatment of 14 with LiR or Mg and DMF resulted in the formation of (R,S)-2-(N,N-dimethylaminomethyl)ferrocenyl(4-formylphenyl)dimethylsilane (18). The crystal structures of 7, 12 and 15 were determined by single crystal X-ray analyses. 57Fe-M?ssbauer spectroscopy gives evidence of a significant electronic coupling between the ferrocenyl unit and the organic acceptor moiety of the molecules in the ground state.

Poly(silyleneethynylenephenylene) and poly(silylenephenyleneethynylenephenylene)s: Synthesis and photophysical properties related to charge transfer

Novel poly(dimethylsilyleneethynylenephenylene) and poly(dimethyl (or diphenyl) silylenephenyleneethynylenephenylene)s without diyne defects were synthesized by using the Pd/Cu-catalyzed AB-type coupling reaction. 6's showed small but clear π-to-σ charge-transfer absorption bands at longer wavelengths (>340 nm) than those of π-π* absorption bands (max ca. 370 nm) with a large Stokes shift. On the other hand, when excited at the charge-transfer absorption wavelengths, 6's exhibited only the intramolecular charge-transfer emission with a maximum above 390 nm. This suggests that the indigo blue light emission of 6's is due to the charge-transfer phenomenon and not to the locally excited π* state. The charge-transfer character of 6's was clearly verified by the shift of emission in polar solvents.

Synthesis of new mixed ring zirconocenes and evidence of ring loss

The synthesis of the substituted silyl cyclopentadiene ligand [C5H5-Si(CH3)2(p-C6H 4Br)] (CpSiH) (1) is described. Deprotonation of (1) gives (CpSiLi) (2) which reacts with 1/2 ZrCl4 to produce the bent, sandwich complex Zr(CpSi)2Cl2 (3). Compound (3) can be alkylated to give Zr(CpSi)2(CH3)2 (4). Reaction of Cp*ZrCl3·(Et2O)1/2 with (2) in ether produces (3) and Zr(CpSi)(C5Me5)Cl2 (5) as the minor and major products, respectively, whereas reaction in toluene produces only 5. Et2O and THF are found to catalyze the observed ring loss during the synthesis of 5. Alkylation of 5 produces Zr(CpSi)(C5Me5)(CH3)2 (6).

Comparison between SiMe2 and CMe2 spacers as σ-bridges for photoinduced charge transfer

The potential of dimethylsilylene and isopropylidene σ-spacers as bridges for photoinduced charge transfer (CT) in 4-cyano-4'-(dimethylamino)- and 4-cyano-4'-methoxy-substituted diphenyldimethylsilanes and 2,2-diphenylpropanes was studied. Fluorescence solvatochromism and time-resolved microwave conductivity measurements show that upon photoexcitation a charge separated state (D.+σA.-)* is populated in all compounds. Excited state dipole moments for a given donor-acceptor combination are, irrespective of the bridge, equal. The CT states of the silanes are however lying at lower energies, implying that the presence of silicon thermodynamically facilitates the CT process. Cyclic voltammetry data of model compounds show that this is a consequence of the lowering of the acceptor reduction potential by the silicon bridge. It was however inferred from radiative decay rates that the electronic coupling between the CT and locally excited states as well as the coupling between the ground and CT state is larger for the carbon-bridged compounds. As shown by both solution and solid state electronic spectra and radiative decay rates, the photophysics of the DσA compounds are dominated by intensity borrowing of the CT transitions from transitions localized in the Dσ and σA chromophores.

Synthesis and polymerization of p-pentamethyldisiloxanyl-α,β,β-trifluorostyrene and the oxygen permeability of the polymer

A novel monomer, p-pentamethyldisiloxanyl-α,β,β-trifluorostyrene, has been synthesized and polymerized to give a white polymer.Membranes obtained from the polymer exhibited an oxygen permeability coefficient (PO2: cc(STP) cm/cm2scmHg) and an oxygen separation factor (α=PO2/PO2) of 1.8 * 10-9 amd 2.4, respectively.The PO2 value is considerably higher than values for other poly(mono-substituted tetrafluoroethylenes).The introduction of a pentamethyldisiloxanylphenyl group into poly(tetrafluoroethylene) has been found to be very effective the enhancement of PO2 values.