930301-82-9Relevant academic research and scientific papers
A Radical Mechanism for Frustrated Lewis Pair Reactivity
Liu, Liu (Leo),Cao, Levy L.,Shao, Yue,Ménard, Gabriel,Stephan, Douglas W.
supporting information, p. 259 - 267 (2017/09/05)
The frustrated Lewis pairs (FLPs) derived from tBu3P and E(C6F5)3 (E = B, Al) react with pO2C6Cl4 and Ph3SnH to give [tBu3POC6Cl4OE(C6F5)3] (E = B 1, Al 2), [tBu3PSnPh3][HB(C6F5)3] 3, and [tBu3PSnPh3][(μ-H)(Al(C6F5)3)2] 4. These products form via the accepted two-electron process involving a transient “encounter complex.” In contrast, the corresponding reactions of Mes3P and E(C6F5)3 (E = B, Al) with pO2C6Cl4 give [(Mes3POC6Cl4OE(C6F5)3] (E = B 8, Al 9); however, the identification of the intermediates [Mes3P·]2[(C6F5)3EOC6Cl4OE(C6F5)3] (E = B 5, Al 6) supports a mechanism that proceeds via a single-electron transfer process. This is further supported by the reactions of Mes3P and E(C6F5)3 (E = B, Al) with Ph3SnH, which yielded [Mes3PH][HB(C6F5)3] 10 and [Mes3PH][(μ-H)(Al(C6F5)3)2] 11, respectively, with the concurrent formation of Ph3SnSnPh3.
Metal-free hydrogen activation by the frustrated lewis pairs of ClB(C 6F5)2 and HB(C6F5) 2 and bulky lewis bases
Jiang, Chunfang,Blacque, Olivier,Berke, Heinz
, p. 5233 - 5239 (2010/01/06)
The frustrated Lewis pair (FLP) derived from CIB(C6F 5)2 and the bulky Lewis bases 2,2,6,6tetramethylpiperidine (TMP), tri-tert-butylphosphine, and tris(2,4,6-trimethylphenyl)phosphine cleaved H2 heterolytically to form the intermediate anion [HClB(C6F5)2]-, which quickly underwent hydride/chloride exchange with the remaining CIB(C6F 5)2 to give the known compound [HB(C6F 5)2]., (n = 1 or 2) and the anion [Cl2B(C 6F5)2]- present in the products [TMPH][Cl2B(C6F5)2] (1a), [t-Bu 3PH][Cl2B(C6F5)2] (2a), and [Mes3PH][Cl2B(C6F5)2] (3a). [HB(C6F5)2]., forms Lewis adducts with TMP and t-Bu3P: TMP-BH(C6F5)2 (1b) and t-Bu3P-BH(C6F5)2 (2b). The Lewis adduct t-Bu3P-BH(C6F5)2 was found capable of generating a FLP at elevated temperature and was reacted with H 2, producing the splitting product [t-Bu3PH][H 2B(C6F5)2] (2c). Mes3P forms no Lewis adduct with [HB(C6F5)2] n, but a FLP, which was also capable of splitting H2 to yield initially [Mes3PH][H2B(C6F 5)2]. The [H2B(C6F5) 2]- anion underwent disproportionation to form [MeS 3PH][HB(C6F5)3] (3b), Mes 3P, [H2B(C6F5)]2, and H2. Similarly, 2,4,6-tri-tert-butylpyridine (TTBP) and [HB(C 6F5)2]., gave in the presence of H2 the final products [TTBPH][HB(C6F5)3] salt and [H2B(C6F5)]2. The contrasting reactivities of the t-Bu3P/[BH(C6F5) 2]n, Mes3P/[HB(C6F5)2]., and TTBP/[HB(C6F5)2]., pairs were explained on the basis of the different pKa'& of the [LBH]+ cations. After disproportionation of the [H2B(C6F 5)2]- anion to give [Mes3PH] [HB(C6F5)3] (3b) or [TTBPH][HB(C 6F5)3] (4a), the also formed [H 3B(C6F5)]- anion reacted with the more acidic cations ([MeS3PH]+, [TTBPH]+) to give H2 and syn- and anti-[H2B(C6F 5)]2 (3c). 1a, 2a, 3a, and 4a were studied by single-crystal X-ray diffraction analysis.
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
