- [2+2+1]cycloadditions of bis(dialkylamino)acetylenes with SiI 2(Idip): Syntheses and reactivity studies of unprecedented 2,3,4,5-tetraamino-1 H-siloles
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A novel method for the synthesis of 1H-siloles is presented. It involves a [2+2+1] cycloaddition of the ynediamines R2N-C≡C-NR2 (R=Me, Et) with SiI2(Idip) (Idip=1,3-bis(2,6-diisopropylphenyl) imidazolin-2-ylidene) to affor
- Lebedev, Yury N.,Das, Ujjal,Chernov, Oleg,Schnakenburg, Gregor,Filippou, Alexander C.
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- Chemical vapour transport of intermetallic phases, II: The system Fe-Si
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Five phases exist in the system Fe-Si: Fe3Si, Fe2Si, Fe5Si3, FeSi, α- and β-FeSi2. All phases could be prepared by chemical transport with iodine as transport agent in the temperature range between T1 (700 °C) and T2 (1030 °C). In a attempted systematic clarification of the chemical transport reactions of all phases in the system, the effective transport equilibria were determined. Thermodynamic calculations show satisfactory agreement between calculation and experiment.
- Bosholm,Oppermann,D?britz
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- Silicon Tetrakis(trifluoromethanesulfonate): A Simple Neutral Silane Acting as a Soft and Hard Lewis Superacid
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A facile synthesis and isolation of pristine silicon tetrakis(trifluoromethanesulfonate), Si(OTf)4, is reported, acting as the first neutral silicon-based Lewis superacid suitable towards soft and hard Lewis bases. Its OTf groups have a dual function: they are excellent leaving groups and modulate the degree of reactivity towards soft and hard Lewis bases. Exposed to soft Lewis donors, Si(OTf)4 leads to [L2Si(OTf)4] complexes (L=isocyanide, thioether and carbonyl compounds) with retention of all Si?OTf bonds. In contrast, it can cleave C?X bonds (X=F, Cl) of hard organic Lewis bases with a high tendency to form SiX4 (X=F, Cl) after halide/triflate exchange. Most notable, Si(OTf)4 allows a gentle oxydefluorination of mono- and bis(trifluoromethyl)benzenes, resulting in the formation of the corresponding benzoylium species, which are stabilized by the weakly coordinating [Si(OTf)6] dianion.
- Driess, Matthias,Hermannsdorfer, André
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supporting information
p. 13656 - 13660
(2021/05/03)
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- Reaction of Silicon Difluoride with Halogens: a Reinvestigation
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Reactions of SiF2 with halogens have been reinvestigated by both co-condensation and gas-phase methods.The co-condensation method yields a number of fluorohalogenosilanes including mono-, di-, and higher silane derivatives.These compounds contain SiF, SiF2, and SiF3 units.The reactivity towards SiF2 decreases from chlorine through bromine to iodine.While chlorine and bromine give rise to a number of fluorohalogenosilanes, iodine yields only the monosilane derivatives.In contrast, the gas-phase reaction do not progress to any appreciable extent.The products have been characterized by mass spectrometry and 19F and 29Si n.m.r. spectroscopy.Many have been identified for the first time.
- Suresh, Bettadapura S.,Thompson, James Charlton
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p. 1123 - 1126
(2007/10/02)
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