Frustrated Lewis Pair Inspired Carbon Dioxide Reduction by a Ruthenium Tris(aminophosphine) Complex

Sgro, Michael J.; Stephan, Douglas W.

doi:10.1002/ange.201205741

Cited by 26 publications

(5 citation statements)

References 41 publications

(30 reference statements)

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“…Such a system would be one of the rare examples for FLP reactivity without boron-containing Lewis acids and the first to use an imidazolinium ion akin to methenyl-H 4 MPT + as the Lewis acid. Conceptually related to recently reported metal–borane complexes, − the envisioned system would also be the first with a transition-metal compound acting as a Lewis base in a “real” FLP, complementing recent examples of FLP systems that feature transition metals as Lewis acids. − It should finally be noted that recent quantum mechanics/molecular mechanics (QM/MM) calculations on snapshots of the H 2 activation in [Fe] hydrogenase by Reiher et al indeed suggested a metal-mediated mechanism reminiscent of H 2 activation by frustrated Lewis pairs, though using the deprotonated pyridinol as a base.…”

Section: Introductionmentioning

confidence: 75%

Functional Model for the [Fe] Hydrogenase Inspired by the Frustrated Lewis Pair Concept

et al. 2014

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[Fe] hydrogenase (Hmd) catalyzes the heterolytic splitting of H2 by using, in its active site, a unique organometallic iron-guanylylpyridinol (FeGP) cofactor and, as a hydride acceptor, the substrate methenyltetrahydromethanopterin (methenyl-H4MPT(+)). The combination FeGP/methenyl-H4MPT(+) and its reactivity bear resemblance to the concept of frustrated Lewis pairs (FLPs), some of which have been shown to heterolytically activate H2. The present work exploits this interpretation of Hmd reactivity by using the combination of Lewis basic ruthenium metalates, namely K[CpRu(CO)2] (KRp) and a related polymeric Cp/Ru/CO compound (Rs), with the new imidazolinium salt 1,3-bis(2,6-difluorophenyl)-2-(4-tolyl)imidazolinium bromide ([(Tol)Im(F4)](+)Br(-)) that was designed to emulate the hydride acceptor properties of methenyl-H4MPT(+). Solid-state structures of [(Tol)Im(F4)](+)Br(-) and the corresponding imidazolidine H(Tol)Im(F4) reveal that the heterocycle undergoes similar structural changes as in the biological substrate. DFT calculations indicate that heterolytic splitting of dihydrogen by the FLP Rp(-)/[(Tol)Im(F4)](+) is exothermic, but the formation of the initial Lewis pair should be unfavorable in polar solvents. Consequently the combination Rp(-)/[(Tol)Im(F4)](+) does not react with H2 but leads instead to side products from nucleophilic substitution (k = 4 × 10(-2) L mol (-1) s(-1) at room temperature). In contrast, the heterogeneous combination Rs/[(Tol)Im(F4)](+) does split H2 heterolytically to give H(Tol)Im(F4) and HRuCp(CO)2 (HRp) or D(Tol)Im(F4) and DRp when using D2. The reaction has been followed by (1)H/(2)H and (19)F NMR spectroscopy as well as by IR spectroscopy and reaches 96% conversion after 1 d. Formation of H(Tol)Im(F4) under these conditions demonstrates that superelectrophilic activation by protonation, which has been proposed for methenyl-H4MPT(+) to increase its carbocationic character, is not necessarily required for an imidazolinium ion to serve as a hydride acceptor. This unprecedented functional model for the [Fe] hydrogenase, using a Lewis acidic imidazolinium salt as a biomimetic hydride acceptor in combination with an organometallic Lewis base, may provide new inspiration for biomimetic H2 activation.

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Section: Introductionmentioning

confidence: 75%

Functional Model for the [Fe] Hydrogenase Inspired by the Frustrated Lewis Pair Concept

et al. 2014

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“…A metal‐based FLP 39 derived from a Ru complex is also active catalyst for the hydroboration of CO 2 in the presence of excess HBpin, HBcat and 9‐BBN, affording MeO B and B O B species (Scheme 8). [ 71 ] Other catalysts based on P/B 40 or C 3 H 2 (NPR 2 ) 2 BC 8 H 14 41 are active for the catalytic hydroboration of CO 2 to MeO B and B O B species. [ 72,73 ] Recently, Hou et al .…”

Section: Overviews In Catalysismentioning

confidence: 99%

Frustrated Lewis Pairs: Discovery and Overviews in Catalysis

Zhang

2020

Chin. J. Chem.

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Frustrated Lewis Pairs (FLPs) are derived from simple combinations of Lewis acids (electron acceptors) and Lewis bases (electron donors), in which steric demands prevent from forming classical Lewis acid-base adducts. Since 2006, FLP chemistry has emerged as a novel strategy for the design and application of main-group chemistry and development of new metal-free catalytic processes. This strategy has been applied to stoichiometric reactivity and then extended to catalysis. In this review, we briefly summarize the representative discoveries and developments of FLP chemistry in the field of catalysis, including hydrogenation, hydrosilylation, reduction of CO2, transformations of alkynes to organic derivatives, C-H bond borylation and polymerization. Nan Li (left) was born in Henan, China, in 1988. She received her BS degree from Xinyang University in 2012. She obtained her PhD degree in 2017, supervised by Professor Bing-Tao Guan at Nankai University. Following her graduate research, she moved to the college of chemistry at Peking University as a Postdoctoral Fellow in the laboratory of Professor Zhenfeng Xi and Professor Wen-Xiong Zhang (2017-2019). Wen-Xiong Zhang (right) received his B.Sc. from Hunan Normal University in 1996, his MSc from Guangxi Normal University in 1999, and his PhD from Nankai University with professor Li-Cheng Song in 2003. He carried out postdoctoral research at Peking University with Prof. Zhenfeng Xi and at Riken in Japan with Prof. Zhaomin Hou. In 2007, he joined College of Chemistry at Peking University as an Associate Professor, where he is now a Professor. His research interests include design, synthesis and small molecule activation of rare-earth-metal heterocycles, metal-catalyzed C-N bond activation, and carbodiimide-based organic synthesis to construct N-containing heterocycles.

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“…Such cationic species received an immense increase in interest during the last few years due to the development of transition-metal frustrated Lewis pairs (tm-FLPs). − FLPs have been shown to be a powerful tool for numerous bond activation reactions and small-molecule activations. Replacing the Lewis acid compound, which is usually a polyfluorinated arylborane, with an electrophilic transition-metal center offers the promising ability to combine the powerful small-molecule activation chemistry of FLPs with the extensively studied suite of catalytically relevant reactions and has already shown new reaction pathways. − It has to be mentioned that examples of tm-FLPs in which the Lewis acid is replaced by a transition metal have been mostly focused on zirconium, − whereas only a few examples with titanium, − hafnium, ,, and ruthenium , have been reported. Whether the frustrated character between the Lewis acid and the Lewis base is present is strongly dependent on the steric and electronic properties of each part.…”

Section: Introductionmentioning

confidence: 99%

Electrophilic d⁰ Cations of Group 4 Metals (M = Ti, Zr, Hf) Derived from Monopentafulvene Complexes: Direct Formation of Tridentate Cp,O,P-Ligands

et al. 2018

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The reactions of the monopentafulvene complexes Ti1a and Ti1b with the general formula [Cp*Ti(Cl)(π-η 5 :σ-η 1 -C 5 H 4 CR 2 )] (R = p-tolyl (Ti1a); CR 2 = adamantylidene (Ti1b)) with the bidentate P,O-ligand precursor L1, featuring a diphenylphosphine and a hydroxyl functional group, are reported, yielding the corresponding complexes Ti2a and Ti2b in good yields as the result of deprotonation. A chloride/methyl exchange reaction and subsequent reaction with B(C 6 F 5 ) 3 was envisaged to yield the corresponding cationic complexes. Instead, the methylation reactions of Ti2a and Ti2b with methyllithium or methylmagnesium bromide selectively yielded the doubly methylated titanium complexes Ti3a and Ti3b with abstraction of LiCl and the lithium salt of the bidentate P,O-ligand. To avoid this reaction, the P,O-ligand precursor L2 was prepared, featuring a carbonyl group instead of the hydroxyl functional group. This change in the general reaction sequence allowed the preparation of a new family of cationic titanium complexes Ti6a and Ti6b and was transferred to the heavier congeners zirconium (Zr4) and hafnium (Hf4). Every step of the reaction pathway was performed under mild reaction conditions and in good to very good yields. The insertion of the carbonyl group into the M−C exo bond of the monopentafulvene complexes Ti1a, Ti1b, Zr1, and Hf1, and consequently the formation of a C−C bond, proved to be mandatory for the methylation and subsequent abstraction of the methyl group by B(C 6 F 5 ) 3 . In effect, a tridentate Cp,O,P-ligand was directly introduced into the coordination spheres of the respective group 4 metals within the cationic complexes. In all cases the phosphorus shows a persistent interaction between the Lewis acidic metal center and the Lewis basic phosphine moiety, as shown by NMR analyses and in the solid state. Every complex was thoroughly characterized, including several X-ray diffraction analyses of each class of compounds reported here.

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Frustrated Lewis Pair Inspired Carbon Dioxide Reduction by a Ruthenium Tris(aminophosphine) Complex

Cited by 26 publications

References 41 publications

Functional Model for the [Fe] Hydrogenase Inspired by the Frustrated Lewis Pair Concept

Functional Model for the [Fe] Hydrogenase Inspired by the Frustrated Lewis Pair Concept

Frustrated Lewis Pairs: Discovery and Overviews in Catalysis

Electrophilic d⁰ Cations of Group 4 Metals (M = Ti, Zr, Hf) Derived from Monopentafulvene Complexes: Direct Formation of Tridentate Cp,O,P-Ligands

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Frustrated Lewis Pair Inspired Carbon Dioxide Reduction by a Ruthenium Tris(aminophosphine) Complex

Cited by 26 publications

References 41 publications

Functional Model for the [Fe] Hydrogenase Inspired by the Frustrated Lewis Pair Concept

Functional Model for the [Fe] Hydrogenase Inspired by the Frustrated Lewis Pair Concept

Frustrated Lewis Pairs: Discovery and Overviews in Catalysis

Electrophilic d0 Cations of Group 4 Metals (M = Ti, Zr, Hf) Derived from Monopentafulvene Complexes: Direct Formation of Tridentate Cp,O,P-Ligands

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Electrophilic d⁰ Cations of Group 4 Metals (M = Ti, Zr, Hf) Derived from Monopentafulvene Complexes: Direct Formation of Tridentate Cp,O,P-Ligands