Reversible cooperative dihydrogen binding and transfer with a bis-phosphenium complex of chromium

Birchall, Nicholas; Feil, Christoph M.; Gediga, Michael; Nieger, Martin; Gudat, Dietrich

doi:10.1039/d0sc03773g

Cited by 12 publications

(10 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Numerous examples of pincer ligands engaging in novel catalytic and stoichiometric MLC-related reactions have been and continue to be reported. − Yet, despite the large number of pincer ligands for which MLC is based on a coordinating N atom, − there are very few examples involving the next congener, phosphorus. In particular, in spite of the great value that has been proven for addition of H 2 across M–N bonds, there are relatively few examples of H 2 addition across a phosphorus metal bond − and even fewer examples of the reverse elimination of H 2 . , …”

Section: Introductionmentioning

confidence: 99%

“…In particular, in spite of the great value that has been proven for addition of H 2 across M−N bonds, there are relatively few examples of H 2 addition across a phosphorus metal bond 21−26 and even fewer examples of the reverse elimination of H 2 . 26,27 Phosphorus has been referred to as "the carbon copy" 28 because of numerous similarities between the chemistry, including the coordination chemistry, of these elements. PCP-type pincer ligands, in which the coordinating atom of the central group is typically a formally anionic carbon, have played an important role in organometallic chemistry in recent decades.…”

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reactivity of Iridium Complexes of a Triphosphorus-Pincer Ligand Based on a Secondary Phosphine. Catalytic Alkane Dehydrogenation and the Origin of Extremely High Activity

et al. 2022

View full text Add to dashboard Cite

The selective functionalization of alkanes and alkyl groups is a major goal of chemical catalysis. Toward this end, a bulky triphosphine with a central secondary phosphino group, bis(2-di-t-butyl-phosphinophenyl)phosphine (tBuPHPP), has been synthesized. When complexed to iridium, it adopts a meridional (“pincer”) configuration. The secondary phosphino H atom can undergo migration to iridium to give an anionic phosphido-based–pincer (tBuPPP) complex. Stoichiometric reactions of the (tBuPPP)Ir complexes reflect a distribution of steric bulk around the iridium center in which the coordination site trans to the phosphido group is quite crowded; one coordination site cis to the phosphido is even more crowded; and the remaining site is particularly open. The (tBuPPP)Ir precursors are the most active catalysts reported to date for dehydrogenation of n-alkanes, by about 2 orders of magnitude. The electronic properties of the iridium center are similar to that of well-known analogous (RPCP)Ir catalysts. Accordingly, DFT calculations predict that (tBuPPP)Ir and (tBuPCP)Ir are, intrinsically, comparably active for alkane dehydrogenation. While dehydrogenation by (RPCP)Ir proceeds through an intermediate trans-(PCP)IrH2(alkene), (tBuPPP)Ir follows a pathway proceeding via cis-(PPP)IrH2(alkene), thereby circumventing unfavorable placement of the alkene at the bulky site trans to phosphorus. (tBuPPP)Ir and (tBuPCP)Ir, however, have analogous resting states: square planar (pincer)Ir(alkene). Alkene coordination at the crowded trans site is therefore unavoidable in the resting states. Thus, the resting state of the (tBuPPP)Ir catalyst is destabilized by the architecture of the ligand, and this is largely responsible for its unusually high catalytic activity.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Reactivity of Iridium Complexes of a Triphosphorus-Pincer Ligand Based on a Secondary Phosphine. Catalytic Alkane Dehydrogenation and the Origin of Extremely High Activity

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The vast majority of these rely on second- and third-row transition metals (M = Zr, Hf, Ru, , Ir) or alkali metals . Examples with first-row metals are even more rare, − and so far, these have all relied on N-heterocyclic phosphido (NHP) donor groups. The NHP ligands temper the basicity of phosphido ligands (Figure , middle), but this strategy precludes readily available diaryl- and dialkylphosphido groups in MLC with first-row metals.…”

Section: Introductionmentioning

confidence: 99%

Activation of H₂ with Dinuclear Manganese(I)-Phosphido Complexes

2021

View full text Add to dashboard Cite

There are few reports of activation of H2 across metal–phosphido linkages, and all of the first-row metal examples use N-heterocyclic phosphido donors. In this report, we highlight the discovery of H2 activation using first-row transition-metal phosphido complexes with alkyl and aryl substituents. The complex [Mn(CO)4(μ-PPh2)]2 (1) was treated with H2 (125 °C, 33 h), affording [{Mn(CO)4}(μ-H)(μ-PPh2){Mn(CO)3(Ph2PH)}] (2). Treating 2 with Mn2(CO)10 leads to PH bond activation and formation of [{Mn(CO)4}(μ-H)(μ-PPh2){Mn(CO)4}] (3). The interconversion of 1 to 3 is reversible, as indicated by the treatment of 3 with free Ph2PH, giving 2 at 80 °C or 1 and H2 at 120 °C. The isopropyl analogue of 1, [Mn(CO)4(μ-P(iPr)2)]2 (5), was synthesized by the oxidative addition of [(iPr)2PP(iPr)2] (4) with Mn2(CO)10. The reactivity of 5 is analogous to that of 1, forming [{Mn(CO)4}(μ-H)(μ-P(iPr)2){Mn(CO)3((iPr)2PH}] (6) on treatment with H2, which in turn reacts with Mn2(CO)10, quantitatively affording [{Mn(CO)4}(μ-H)(μ-P(iPr)2){Mn(CO)4}] (7). The chemistry diverges upon use of the tBu substituent. Treating Na[Mn(CO)5] with Cl(tBu)2P results in formation of the bis-(tBu2P) hexacarbonyl complex [Mn(CO)3(μ-PtBu2)]2 (8), a dark green compound with a formal M–M double bond (2.5983(5) Å). 8 reacts sluggishly with H2 to form free tBu2PH and [MnH(CO)4(HPtBu2)] (10). The activation of H2 with 1 is incomplete even at high temperatures. In contrast, facile activation of H2 occurs with [{Mn(CO)3(μ-PPh2)}2(μ-CO)] (1-CO) to yield 2 (84%, 70 °C, 10 h), implicating thermally demanding CO dissociation from 1 as the first step in the H2 activation. PCl bond activation under hydrogenative conditions was also examined. The reactions between Mn2(CO)10 and ClPh2P or Cl(iPr)2P under 1 atm of H2 gave 3 (R = Ph) or 7 (R = iPr) in 50–60% yield, indicating the intermediacy of bisphosphido compounds. When Cl(tBu)2P was used instead, the compounds cis-[Mn(CO)4(H)((tBu2)P)2H)] (10), [Mn(CO)3(H)((tBu2)P)2H] (11), and diaxial-[Mn(CO)4((tBu2)PH)]2 (12) were isolated, indicating PCl bond hydrogenation to phosphines using H2 and Mn2(CO)10.

show abstract

“…Gudat and co-workers have shown that a metal phosphenium complex, ( u NHP Dipp )Mn(CO) 4 ( A ), is active for the catalytic dehydrogenation of ammonia borane and ( u NHP Dipp ) 2 Cr(CO) 3 ( B ) cooperatively activates hydrogen across a Cr–P bond and is active for the photocatalytic hydrogenation of styrene (Scheme ). , Herein, we explore the catalytic activity of (PPP)Co complexes toward alkene hydroboration, hypothesizing that metal–phosphorus cooperativity may be a viable reaction pathway.…”

Section: Introductionmentioning

confidence: 99%

Highly Selective Hydroboration of Terminal Alkenes Catalyzed by a Cobalt Pincer Complex Featuring a Central Reactive N-Heterocyclic Phosphido Fragment

et al. 2021

View full text Add to dashboard Cite

The application of a cobalt pincer complex, (PP Cl P)CoCl 2 , as a precatalyst for the hydroboration of terminal alkenes with pinacolborane (HBPin) is described. The reactions proceed rapidly under mild conditions (room temperature, 30 min) with low catalyst loadings (1 mol %) using KBEt 3 H (2.1 mol %) as an activator to afford terminal hydroboration products with very high selectivity for the anti-Markovnikov product. The precatalyst is effective toward vinyl arenes and aliphatic alkenes and proceeds to an 83−98% yield with these substrates. However, the functional group tolerance of the catalytic system is somewhat limited, as minimal conversion is observed with internal olefins or when pyridine, ketone, or allyl ether functional groups are present. Deuterium labeling studies and spectroscopic identification of the catalyst deactivation product suggest a (PPP)CoH active species.

show abstract

Reversible cooperative dihydrogen binding and transfer with a bis-phosphenium complex of chromium

Abstract: The reversible reaction of H2 with a bis-phosphenium complex of chromium provides a rare example of 3d transition metal/phosphenium cooperativity. Photolysis induces the activation of H2 and yields a spectroscopically...

Cited by 12 publications

References 35 publications

Reactivity of Iridium Complexes of a Triphosphorus-Pincer Ligand Based on a Secondary Phosphine. Catalytic Alkane Dehydrogenation and the Origin of Extremely High Activity

Reactivity of Iridium Complexes of a Triphosphorus-Pincer Ligand Based on a Secondary Phosphine. Catalytic Alkane Dehydrogenation and the Origin of Extremely High Activity

Activation of H₂ with Dinuclear Manganese(I)-Phosphido Complexes

Highly Selective Hydroboration of Terminal Alkenes Catalyzed by a Cobalt Pincer Complex Featuring a Central Reactive N-Heterocyclic Phosphido Fragment

Contact Info

Product

Resources

About

Reversible cooperative dihydrogen binding and transfer with a bis-phosphenium complex of chromium

Abstract: The reversible reaction of H2 with a bis-phosphenium complex of chromium provides a rare example of 3d transition metal/phosphenium cooperativity. Photolysis induces the activation of H2 and yields a spectroscopically...

Cited by 12 publications

References 35 publications

Reactivity of Iridium Complexes of a Triphosphorus-Pincer Ligand Based on a Secondary Phosphine. Catalytic Alkane Dehydrogenation and the Origin of Extremely High Activity

Reactivity of Iridium Complexes of a Triphosphorus-Pincer Ligand Based on a Secondary Phosphine. Catalytic Alkane Dehydrogenation and the Origin of Extremely High Activity

Activation of H2 with Dinuclear Manganese(I)-Phosphido Complexes

Highly Selective Hydroboration of Terminal Alkenes Catalyzed by a Cobalt Pincer Complex Featuring a Central Reactive N-Heterocyclic Phosphido Fragment

Contact Info

Product

Resources

About

Activation of H₂ with Dinuclear Manganese(I)-Phosphido Complexes