41866-81-3Relevant articles and documents
Determination of the gas-phase acidities of halogen-substituted aromatic compounds using the silane-cleavage method
Wenthold,Squires
, p. 17 - 24 (1995)
The gas-phase acidities of halogen-substituted aromatic compounds have been determined in a flowing afterglow-triple quadrupole apparatus with use of the silane cleavage method developed by DePuy and co-workers [C. H. DePuy, S. Gronert, S. E. Barlow, V. M. Bierbaum and R. Damrauer, J. Am. Chem. Sec., 111, 1968 (1989)]. In this method the relative yields of siloxide ion products produced in reactions of OH- with trimethylsilyl- or phenyidimethylsilyl-substituted aromatic compounds are correlated with the difference in gas-phase acidity of the accompanying neutral products. Acidities are reported for different ring-positions in fluoro-, chloro- and bromobenzene, chloro- and bromonaphthalene and benzyl chloride. Excellent precision is achieved in most cases, with assigned uncertainties less than 23 kcal/mol. Goad agreement is obtained between the acidities determined with use of two different types of silane precursor. Halogen-substitution increases the gas-phase acidities of benzene and naphthalene by similar amounts (13-14 kcal/mol). The effects on different ring-positions in benzene and naphthalene are shown to be primarily inductive in nature, falling-off by a consistent 2.5-3.5 kcal/mol per bond separating the acidic site from the haloges-bearing carbon in the chlorine and bromine-substituted systems. Larger effects are evident in the positional acidities of fluorobenzene. The meta and pava position acidities of halobenzenes are shown to be linearly correlated with the acidities of the corresponding meta and pava halophenols, haloanilines and halotoluenes.
Gas- Phase Ion Chemistry of Siloxide and Silamide Ions by Using the Flowing Afterglow. Unusual Rearrangements Involving SiO and SiS Bond Formation
O'Hair, Richard A.J.,Sheldon, John C.,Bowie, John H.,Damrauer, Robert,DePuy, Charles H.
, p. 489 - 496 (2007/10/02)
Siloxide ions undergo O/S exchange reactions with suitable sulfur-containing neutrals, e.g.H3SiO- + CS2 -> H3SiS- + COS.Silamide ions similarly undergo NR/O and NR/S exchange reactions together with nucleophilic displacement reactions, e.g.: .No simple correlation between rate and mechanism is observed for all the studied reactions.
Gas-Phase Reactions of Anions with Substituted Silanes
DePuy, C. H.,Bierbaum, Veronica M.,Flippin, L. A.,Grabowski, Josef J.,King, Gary K.,et al.
, p. 5012 - 5015 (2007/10/02)
The gas-phase reactions of fluoride, amide, hydroxide, and methoxide ions with a variety of substituted silanes have been studied by the flowing afterglow technique.Fluoride reacts readily with trimethylsilyl derivatives to displace benzyl, alkenyl, and alkynyl anions.These reactions have also been used to generate specific structural isomers (CH3CC- and CH2C=C=CH-).Anions more basic than phenide ion cannot be produced in this manner, and their parent trimethylsilanes interact with fluoride by more complex mechanisms.Amide, hydroxide, and methoxide ions react with substituted trimethylsilanes by both displacement and proton abstraction whenever an acidic hydrogen is present; in the absence of displaceable groups and acidic hydrogen, the reactions of amide, hydroxide, and methoxide parallel those of fluoride ion.
