10536-53-5Relevant academic research and scientific papers
Ueber α,ω-uebergangsmetallsubstituierte Oligosilane
Hengge, E.,Eibl, M.,Stadelmann, B.
, p. 523 - 528 (1993)
Methyloligosilanes with n=3, 4, 5 and 6 with dicarbonyl-cyclopentadienyl-iron- and tricarbonyl-triphenylphosphane-cobalt-groups in terminal positions were synthesized for the first time and characterized by NMR, IR, and MS.The NMR spectra were discussed in detail. Key words: Cobalt, iron; NMR; oligosilanes; silanes.
Hydrogen-Bridged Oligosilanylsilyl Mono- and Oligosilanylsilyl Dications
Nimoth, Jelte P.,Müller, Thomas
supporting information, (2022/01/08)
Hydrogen-bridged oligosilanylsilyl borates 8 [B(C6F5)4], 9[B(C6F5)4] and diborates 10 [B(C6F5)4]2 have been prepared by hydride transfer between α-ω-dihydrido- (11) and branched tetrahydrido-oligosilanes (13) and trityl cation. The obtained cyclic intramolecularly stabilized silylium ions 8, 9 and bissilylium ion 10 were characterized by low temperature NMR spectroscopy supported by the results of density functional calculations. The branched Si?H?Si monocation 9 undergoes at low temperatures a fast degenerate rearrangement, which exchanges the Si?H groups with a barrier of 31 kJ mol?1 via an antarafacial transition state. Reaction of the branched monocation 9 with a second equivalent of trityl cation or of the branched oligosilane 13 with two equivalents of trityl cation, gives at ?80 °C the corresponding bissilylium ion 10, an example for a new class of highly reactive poly-Lewis acids.
Conductive molecular silicon
Klausen, Rebekka S.,Widawsky, Jonathan R.,Steigerwald, Michael L.,Venkataraman, Latha,Nuckolls, Colin
, p. 4541 - 4544 (2012/04/23)
Bulk silicon, the bedrock of information technology, consists of the deceptively simple electronic structure of just Si-Si σ bonds. Diamond has the same lattice structure as silicon, yet the two materials have dramatically different electronic properties. Here we report the specific synthesis and electrical characterization of a class of molecules, oligosilanes, that contain strongly interacting Si-Si σ bonds, the essential components of the bulk semiconductor. We used the scanning tunneling microscope-based break-junction technique to compare the single-molecule conductance of these oligosilanes to those of alkanes. We found that the molecular conductance decreases exponentially with increasing chain length with a decay constant β = 0.27 ± 0.01 A-1, comparable to that of a conjugated chain of C = C π bonds. This result demonstrates the profound implications of σ conjugation for the conductivity of silicon.
Dearylation of α,ω-diphenylpermethylated oligosilanes with triflic acid
Ruehl, Karen E.,Matyjaszewski, Krzysztof
, p. 1 - 12 (2007/10/02)
The relative rates of displacement of phenyl groups for a series of α,ω-diphenylpermethylated oligosilanes with the formula Ph(SiMe2)nPh (n = 2-5) were studied.Triflic acid was utilized in the displacement reactions which occur as a two-step process with protonation at the ipso-carbon atom as the rate limiting step.The results showed the displacement of the first phenyl group is more facile than the second group.The largest difference in reactivities is found for the disilane.Competitive displacement reactions between various oligomers were analyzed to establish the influence of the chain length of oligosilanes on the relative reactivities of the terminal phenyl groups.Both the first and second phenyl group displacement reactions are faster for the longer chain oligomers than the shorter analogs.The 13C NMR spectra of the oligosilanes indicate the highest electron density on the ipso-carbon atoms in the disilane, in contrast to its lowest reactivity.This is interpreted by the increased stabilization of the positive charge in the transition state with an increase in the chain length.Thus, the reactivities of oligosilanes are governed by the structures of the transition states rather than the ground states.
