Cationic Ti(iv) and neutral Ti(iii) titanocene–phosphinoaryloxide frustrated Lewis pairs: hydrogen activation and catalytic amine-borane dehydrogenation

Chapman, Andy M.; Wass, Duncan F.

doi:10.1039/c2dt30168g

Cited by 68 publications

(57 citation statements)

References 40 publications

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“…These species also react with alkyl halides leading to alkylation of the P atom and halide capture by Zr (X = Cl, F). In the case of t BuCl, the analogous reaction prompts loss of isobutylene and protonation of P. These metal-based FLPs were also shown to effect the ring-opening of THF affording [Cp' 2 [143] Erker et al [144] treated B(C 6 F 5 ) 3 with Shore's (diphenylphosphinomethyl)zirconocene chloride complex. This system affords two different FLP systems, namely the conventional P/B FLP 225 and/or the P/Zr + FLP 226 (Scheme 75).…”

Section: Group 4 Derived Flpsmentioning

confidence: 95%

Frustrated Lewis Pair Chemistry: Development and Perspectives

2015

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Frustrated Lewis pairs (FLPs) are combinations of Lewis acids and Lewis bases in solution that are deterred from strong adduct formation by steric and/or electronic factors. This opens pathways to novel cooperative reactions with added substrates. Small-molecule binding and activation by FLPs has led to the discovery of a variety of new reactions through unprecedented pathways. Hydrogen activation and subsequent manipulation in metal-free catalytic hydrogenations is a frequently observed feature of many FLPs. The current state of this young but rapidly expanding field is outlined in this Review and the future directions for its broadening sphere of impact are considered.

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Section: Group 4 Derived Flpsmentioning

confidence: 95%

Frustrated Lewis Pair Chemistry: Development and Perspectives

2015

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“…179 This situation is highly reminiscent of bifunctional transition metal catalysts. In this regard it is also important to draw attention to transition metal based FLPs in which metal centers with pendant donors activate a range of small molecule substrates, which has been explored by the groups of Wass [126][127][180][181][182][183] and Erker 128-129,184-188 among others. 130 The concept of FLPs has also been exploited to describe a variety of systems that activate small molecules.…”

Section: Flp Chemistry: In Contextmentioning

confidence: 99%

Frustrated Lewis Pairs

2015

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The articulation of the notion of "frustrated Lewis pairs" (FLPs), which emerged from the discovery that H2 can be reversibly activated by combinations of sterically encumbered Lewis acids and bases, has prompted a great deal of recent activity. Perhaps the most remarkable consequence has been the development of FLP catalysts for the hydrogenation of a range of organic substrates. In the past 9 years, the substrate scope has evolved from bulky polar species to include a wide range of unsaturated organic molecules. In addition, effective stereoselective metal-free hydrogenation catalysts have begun to emerge. The mechanism of this activation of H2 has been explored, and the nature and range of Lewis acid/base combinations capable of effecting such activation have also expanded to include a variety of non-metal species. The reactivity of FLPs with a variety of other small molecules, including olefins, alkynes, and a range of element oxides, has also been developed. Although much of this latter chemistry has uncovered unique stoichiometric transformations, metal-free catalytic hydroamination, CO2 reduction chemistry, and applications in polymerization have also been achieved. The concept is also beginning to find applications in bioinorganic and materials chemistry as well as heterogeneous catalysis. This Perspective highlights many of these developments and discusses the relationship between FLPs and established chemistry. Some of the directions and developments that are likely to emerge from FLP chemistry in the future are also presented.

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“…Furthermore, a cationic Lewis acid component has also been extended to silicon1516, carbon17, in ref. 9 and even the transition-metal (Zr1819 and Ti20) complexes, while the Lewis base component has been extended to O 9 , carbenes21, ethers22, ketones23, and sulfides24. The reduction of CO 2 via FLPs usually consists of two major steps: hydrogen activation and hydrogen transfer to CO 2 , where a hydrogen molecule is first split into a proton (H + ) and a hydride (H − ), and then CO 2 is reduced via a concerted or sequential transfer of H + and H − to CO 2 .…”

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confidence: 99%

Be12O12 Nano-cage as a Promising Catalyst for CO2 Hydrogenation

Zhu

et al. 2017

Sci Rep

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An efficient conversion of CO2 into valuable fuels and chemicals has been hotly pursued recently. Here, for the first time, we have explored a series of M12x12 nano-cages (M = B, Al, Be, Mg; X = N, P, O) for catalysis of CO2 to HCOOH. Two steps are identified in the hydrogenation process, namely, H2 activation to 2H*, and then 2H* transfer to CO2 forming HCOOH, where the barriers of two H* transfer are lower than that of the H2 activation reaction. Among the studied cages, Be12O12 is found to have the lowest barrier in the whole reaction process, showing two kinds of reaction mechanisms for 2H* (simultaneous transfer and a step-wise transfer with a quite low barrier). Moreover, the H2 activation energy barrier can be further reduced by introducing Al, Ga, Li, and Na to B12N12 cage. This study would provide some new ideas for the design of efficient cluster catalysts for CO2 reduction.

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Cationic Ti(iv) and neutral Ti(iii) titanocene–phosphinoaryloxide frustrated Lewis pairs: hydrogen activation and catalytic amine-borane dehydrogenation

Cited by 68 publications

References 40 publications

Frustrated Lewis Pair Chemistry: Development and Perspectives

Frustrated Lewis Pair Chemistry: Development and Perspectives

Frustrated Lewis Pairs

Be12O12 Nano-cage as a Promising Catalyst for CO2 Hydrogenation

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