930301-81-8Relevant academic research and scientific papers
Reductive Dehydrogenation of a Stannane via Multiple Sn?H Activation by Frustrated Lewis Pairs
Sindlinger, Christian P.,Aicher, Frederik S. W.,Schubert, Hartmut,Wesemann, Lars
supporting information, p. 2198 - 2202 (2017/02/15)
A bulky substituted stannane Ar*SnH3(Ar=2,6-(2′,4′,6′-triisopropylphenyl)phenyl) was treated with the well-known frustrated Lewis pair (FLP) PtBu3/B(C6F5)3in varying stoichiometries. To some degree, h
Novel B(Ar′)2(Ar″) hetero-tri(aryl)boranes: A systematic study of Lewis acidity
Blagg, Robin J.,Simmons, Trevor R.,Hatton, Georgina R.,Courtney, James M.,Bennett, Elliot L.,Lawrence, Elliot J.,Wildgoose, Gregory G.
supporting information, p. 6032 - 6043 (2016/04/26)
A series of homo- and hetero-tri(aryl)boranes incorporating pentafluorophenyl, 3,5-bis(trifluoromethyl)phenyl, and pentachlorophenyl groups, four of which are novel species, have been studied as the acidic component of frustrated Lewis pairs for the heterolytic cleavage of H2. Under mild conditions eight of these will cleave H2; the rate of cleavage depending on both the electrophilicity of the borane and the steric bulk around the boron atom. Electrochemical studies allow comparisons of the electrophilicity with spectroscopic measurements of Lewis acidity for different series of boranes. Discrepancies in the correlation between these two types of measurements, combined with structural characterisation of each borane, reveal that the twist of the aryl rings with respect to the boron-centred trigonal plane is significant from both a steric and electronic perspective, and is an important consideration in the design of tri(aryl)boranes as Lewis acids.
An electrochemical study of frustrated lewis pairs: A metal-free route to hydrogen oxidation
Lawrence, Elliot J.,Oganesyan, Vasily S.,Hughes, David L.,Ashley, Andrew E.,Wildgoose, Gregory G.
supporting information, p. 6031 - 6036 (2014/05/20)
Frustrated Lewis pairs have found many applications in the heterolytic activation of H2 and subsequent hydrogenation of small molecules through delivery of the resulting proton and hydride equivalents. Herein, we describe how H2 can be preactivated using classical frustrated Lewis pair chemistry and combined with in situ nonaqueous electrochemical oxidation of the resulting borohydride. Our approach allows hydrogen to be cleanly converted into two protons and two electrons in situ, and reduces the potential (the required energetic driving force) for nonaqueous H2 oxidation by 610 mV (117.7 kJ mol-1). This significant energy reduction opens routes to the development of nonaqueous hydrogen energy technology.
The hydride-ion affinity of borenium cations and their propensity to activate H2 in frustrated Lewis pairs
Clark, Ewan R.,Del Grosso, Alessandro,Ingleson, Michael J.
supporting information, p. 2462 - 2466 (2013/03/28)
A range of frustrated Lewis pairs (FLPs) containing borenium cations have been synthesised. The catechol (Cat)-ligated borenium cation [CatB(PtBu 3)]+ has a lower hydride-ion affinity (HIA) than B(C 6F5)3. This resulted in H2 activation being energetically unfavourable in a FLP with the strong base PtBu3. However, ligand disproportionation of CatBH(PtBu3) at 100 °C enabled trapping of H2 activation products. DFT calculations at the M06-2X/6-311G(d,p)/PCM (CH2Cl2) level revealed that replacing catechol with chlorides significantly increases the chloride-ion affinity (CIA) and HIA. Dichloro-borenium cations, [Cl 2B(amine)]+, were calculated to have considerably greater HIA than B(C6F5)3. Control reactions confirmed that the HIA calculations can be used to successfully predict hydride-transfer reactivity between borenium cations and neutral boranes. The borenium cations [Y(Cl)B(2,6-lutidine)]+ (Y=Cl or Ph) form FLPs with P(mesityl) 3 that undergo slow deprotonation of an ortho-methyl of lutidine at 20 °C to form the four-membered boracycles [(CH2{NC 5H3Me})B(Cl)Y] and [HPMes3]+. When equimolar [Y(Cl)B(2,6-lutidine)]+/P(mesityl)3 was heated under H2 (4 atm), heterolytic cleavage of dihydrogen was competitive with boracycle formation. DFT and experimental studies indicated that [Cl 2B(2,6-lutidine)]+ has a greater hydride-ion affinity (HIA) than B(C6F5)3. Heating the frustrated Lewis pair formed from [Cl2B(2,6-lutidine)]+ and P(mesityl)3 under H2 resulted in activation of H 2 and deprotonation of lutidine to form the boracycle [(CH 2{NC5H3Me})BCl2] (see scheme). Copyright
Dihydrogen activation with tBu3P/B(C 6F5)3: A chemically competent indirect mechanism via in situ-generated p -TBu2P - C 6F4 - B(C6F5)2
Marwitz, Adam J. V.,Dutton, Jason L.,Mercier, Lauren G.,Piers, Warren E.
supporting information; experimental part, p. 10026 - 10029 (2011/08/22)
A chemically competent indirect pathway for the activation of dihydrogen by the nonmetal Lewis acid/Lewis base pair tBu3P/B(C 6F5)3 is described. The reaction between tBu3P and B(C6F5)3 produces [tBu3PH]+[FB(C6F 5)3]- and the known phosphinoborane p- tBu2P - C6F4 - B(C6F 5)2 (1-tBu) with elimination of isobutylene. At 1:1 stoichiometry, 1-tBu is produced rapidly in detectable quantities and can act as a catalyst for the formation of [tBu 3PH]+[HB(C6F5)3] - from tBu3P and B(C6F 5)3 in the presence of H2. The extent to which this indirect path competes with the direct path is explored.
Reaction of frustrated lewis pairs with conjugated ynones-selective hydrogenation of the carbon-carbon triple bond
Xu, Bao-Hua,Kehr, Gerald,Froehlich, Roland,Wibbeling, Birgit,Schirmer, Birgitta,Grimme, Stefan,Erker, Gerhard
supporting information; experimental part, p. 7183 - 7186 (2011/09/30)
Frustrated, but not frustrating: Frustrated Lewis pairs (FLPs) can undergo selective 1,4-addition reactions with conjugated ynones (see scheme). Upon FLP dihydrogen activation selective hydrogenation of the carbon-carbon triple bond can be achieved, in one case even catalytically. Copyright
Ni→ B interactions in nickel phosphino-alkynyl-borane complexes
Zhao, Xiaoxi,Otten, Edwin,Song, Datong,Stephan, Douglas W.
supporting information; experimental part, p. 2040 - 2044 (2010/07/05)
Boron bends over for nickel : The Ni complexes [{t Bu2PC≡ CB(QFs)2]Ni(cod)] (1) and [({tBu2PC≡ CB(C6F5)2}Ni(NCMc))] (2) derived from the reaction between the phosphinoalkynyl-borane tBu2PC≡CB(C 6F5)2 and [Ni(cod)2] exhibit an unprecedented metal-alkyne interaction in which the borane substituent bends towards the metal affording a Ni→B dative interaction. (Chemical Equation Representation). (Chemical Equation Representation).
Facile heterolytic cleavage of dihydrogen by phosphines and boranes
Welch, Gregory C.,Stephan, Douglas W.
, p. 1880 - 1881 (2007/10/03)
The facile heterolytic cleavage of H2 is readily achieved at room temperature by the cooperative action of the Lewis acidic borane and Lewis basic phosphine, where the steric congestion precludes quenching of the acid and base via adduct formation. Copyright
