556-96-7Relevant articles and documents
Bipyridinium and Phenanthrolinium Dications for Metal-Free Hydrodefluorination: Distinctive Carbon-Based Reactivity
Burton, Katherine I.,Elser, Iris,Waked, Alexander E.,Wagener, Tobias,Andrews, Ryan J.,Glorius, Frank,Stephan, Douglas W.
supporting information, p. 11730 - 11737 (2021/07/16)
The development of novel Lewis acids derived from bipyridinium and phenanthrolinium dications is reported. Calculations of Hydride Ion Affinity (HIA) values indicate high carbon-based Lewis acidity at the ortho and para positions. This arises in part from extensive LUMO delocalization across the aromatic backbones. Species [C10H6R2N2CH2CH2]2+ (R=H [1 a]2+, Me [1 f]2+, tBu [1 g]2+), and [C12H4R4N2CH2CH2]2+ (R=H [2 a]2+, Me [2 b]2+) were prepared and evaluated for use in the initiation of hydrodefluorination (HDF) catalysis. Compound [2 a]2+ proved highly effective towards generating catalytically active silylium cations via Lewis acid-mediated hydride abstraction from silane. This enabled the HDF of a range of aryl- and alkyl- substituted sp3(C?F) bonds under mild conditions. The protocol was also adapted to effect the deuterodefluorination of cis-2,4,6-(CF3)3C6H9. The dications are shown to act as hydride acceptors with the isolation of neutral species C16H14N2 (3 a) and C16H10Me4N2 (3 b) and monocationic species [C14H13N2]+ ([4 a]+) and [C18H21N2]+ ([4 b]+). Experimental and computational data provide further support that the dications are initiators in the generation of silylium cations.
PROCESS FOR PREPARING PROPYLENE COPOLYMERS COMPRISING C4-C12-ALPHA OLEFIN COMONOMER UNITS
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Page/Page column 59-60, (2020/01/10)
The present invention relates to a process for producing a copolymer of propylene, optionally ethylene, and at least one comonomer selected from alpha olefins having from 4 to 12 carbon atoms using a specific class of metallocene complexes in combination with a cocatalyst system comprising a boron containing cocatalyst and an aluminoxane cocatalyst, preferably in a multistage polymerization process including a gas phase polymerization step.
Lewis acidity of organofluorophosphonium salts: Hydrodefluorination by a saturated acceptor
Caputo, Christopher B.,Hounjet, Lindsay J.,Dobrovetsky, Roman,Stephan, Douglas W.
, p. 1374 - 1377 (2013/10/08)
Prototypical Lewis acids, such as boranes, derive their reactivity from electronic unsaturation. Here, we report the Lewis acidity and catalytic application of electronically saturated phosphorus-centered electrophilic acceptors. Organofluorophosphonium salts of the formula [(C6F 5)3-xPhxPF][B(C6F5) 4] (x = 0 or 1; Ph, phenyl) are shown to form adducts with neutral Lewis bases and to react rapidly with fluoroalkanes to produce difluorophosphoranes. In the presence of hydrosilane, the cation [(C 6F5)3PF]+ is shown to catalyze the hydrodefluorination of fluoroalkanes, affording alkanes and fluorosilane. The mechanism demonstrates the impressive fluoride ion affinity of this highly electron-deficient phosphonium center.