Role of B(C6F5)3 in catalyst activation, anion formation, and as C6F5 transfer agent

Abstract

The versatile reactivity of B(C6F5)3 in alkene polymerization reactions is summarized. Adduct formation with basic anions such as CN– and NH2– gives extremely weakly co- ordinating diborates, which are the basis of some of the most active polymerization catalysts known to date. By contrast, the reaction of B(C6F5)3 with zirconium half-sandwich complexes leads to extensive C6F5 transfer, including the surprising formation of borole-bridged triple decker complexes. Main group alkyls undergo such C6F5 exchange reactions very readily unless donor ligands are present. Borate salts of new three-coordinate zinc alkyl cations proved to be highly effective catalysts for the ring-opening polymerization of epoxides and lactones.

Combinations of Ethers and B(C6F5)3 Function as Hydrogenation Catalysts

“…[36] At the same time, Nikonov et al [37] provided experimental and theoretical evidence that B(C 6 F 5 ) 3 alone does not activate H 2 . Interestingly, however, these authors and others [38] showed that C 4 H 8 OÀBD 3 undergoes H/ D exchange under pressures of H 2 to produce C 4 H 8 OÀBH 3 . In very recent work, we described the reaction of H 2 with the epoxyborate salt, [tBu 3 PH] [(C 6 F 5 ) 2 BCH(C 6 F 5 )OB(C 6 F 5 ) 3 ], affording the borane-borate salt, [tBu 3 PH][(C 6 F 5 )BCH 2 -(C 6 F 5 )OB(C 6 F 5 ) 3 ].…”

“…Since its discovery in the 1960s, the electrophilic borane B(C 6 F 5 ) 3 [1,2] has been used extensively in catalysis. Perhaps best-known as a co-catalyst or activator for ethylene polymerization, [3][4][5][6][7] this highly electrophilic species has also found applications within a variety of Lewis acid-catalyzed transformations. For example, in the early 2000s, Piers, Gevorgyan, and co-workers pioneered its use in hydrosilylation chemistry.…”

Influence of multidentate N-donor ligands on highly electrophilic zinc initiator for the ring-opening polymerization of epoxides

“…2) [52]. The shorter distances between N(1)eC(1) 1.3131 (15) and C(1)eN (2) With the aim to synthesize a (NHC)ZnEt 2 complex, repeated efforts to generate the free carbene prior to complexation using various bases such as KN(SiMe 3 ) 2 , KOtBu, nBuLi at low temperature and short reaction time led to a complicated mixture. Such reactivity is not surprising for this imidazolinium salt with its electrophilic pyridinylmethyl moieties in the presence of the nucleophilic carbene which tends to initiate the 1,2 migration rearrangement or enetetramines formation [53e58].…”

“…Selected bond lengths (Å) and angles ( ) for d: N(1)eC(1) 1.3131(15), N(2)eC(1) 1.3114(16), N(1)eC(2) 1.4733(15), N(1)eC(4) 1.4563(15), N(2)eC(3) 1.4815(16), N(…”

The supramolecular architecture of the second coordination sphere complex between the ammonia adduct of tris(pentafluorophenyl)borane and pyrimidine: Two interpenetrating chiral (10,3)-a (srs) nets assembled through hydrogen bonding

“…The ammonia adduct of tris(pentafluorophenyl)borane [1][2][3] was one of the first reported complexes of this now ubiquitous Lewis acid [4][5][6][7][8][9]. The enhanced Brønsted acidity renders the (C 6 F 5 ) 3 BÁNH 3 adduct (1) an excellent hydrogen bond donor [10,11].…”