Fundamental and Applied Properties of Borocations

Lewis Acidic Ionic Liquids

“…17, left) [190]. This indicates stronger cation-anion interaction for mononuclear [MCl 4 ] -, compared to dinuclear [M 2 Cl 7 ] -, and is in agreement with observations for halometallate ILs [14,58], and with studies on borenium cations in solutions [28].…”

“…The dimeric [Al 2 Cl 7 ]anion is Lewis acidic [26,27], however, it is worth noting that also here the chloride species pose enough steric hindrance to prevent the formation of higher coordination. However, it is a 'latent' Lewis acid [28] due to an easily broken chloride bridge, which reacts with a base following Scheme 1.…”

“…examples in Schemes 3 and 4)-which lends itself to be translated to IL realm. However, despite increasing interest in these strong Lewis acids in main-group and organic community [28,188,189], their uses in ILs are both very recent and very rare [115,190]. Scheme 3 Synthesis of a borenium ionic liquid via chloride abstraction [191]…”

Enantioselective Main Group Catalysis: Modern Catalysts for Organic Transformations

“…Whilst the ability of lighter group 13 metalloids such as boron is limited in terms of coordination sites, as the reactivity is predominated by the vacant p z orbital, the newly established field of frustrated Lewis pairs (FLPs) has utilized the electron deficiency of group 13 elements to great effect. The concept of frustrated Lewis pairs arises through the formation of bulky strongly Lewis acidic boranes [21][22][23]37,38] and borocations [39], and to a lesser extent phosphonium [40] and silylium cations [41][42][43], in conjunction with sterically crowded Lewis bases such as phosphines, amines or imine reactants, amongst others. This steric obstruction precludes adduct formation allowing interesting and unique transformations to take place as a result of the unquenched reactivity of these donor/acceptor moieties.…”

Borenium Ionic Liquids as Alternative to BF3 in Polyalphaolefins (PAOs) Synthesis

“…It can be reasonably assumed that the methyl group in the alpha position with respect to the nitrogen atom induces steric hindrance and weakens the B-N bond, which is known to encourage disproportionation of the adduct (Equation 2) in chemistry of boron complexes. 32 As such, this equilibrium observed via NMR spectroscopy is an inherent property of the compound, rather than impurity. Adding complexity is the fact that carbocationic oligomerisation of higher olefins with Group 13…”