A photochemical route to a square planar, ruthenium(<scp>iv</scp>)-bis(imide)

Aldrich, Kelly E.; Odom, Aaron L.

doi:10.1039/c9cc01019j

Cited by 7 publications

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References 16 publications

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“…While some imido complexes of ruthenium and osmium exist, these are often in high oxidation states with many strongly donating metal–ligand multiple bonds in a single molecule. Examples of such complexes with osmium include the series Os(O) 4– n (N t Bu) n ( n = 1–4) or Schrock’s trans -Os(NAr) 2 (PMe 3 ) 2 . − Similar to these osmium compounds is the report of Ru(NAr) 2 (PMe 3 ) 2 by Wilkinson. , Ruthenium(VI) bis(imido) compounds containing porphyrin ligands are another class of ruthenium imides well represented in the literature, also in a high oxidation state. − One of the few classes of terminal Ru imido complexes in low oxidations states is Steedman's imido-capped Ru(II) arenes (Chart ). ,,, Ruthenium complexes with bridging imido ligands have also been reported…”

Section: Introductionmentioning

confidence: 99%

“…50−52 Similar to these osmium compounds is the report of Ru(NAr) 2 (PMe 3 ) 2 by Wilkinson. 53,54 Ruthenium(VI) bis(imido) compounds containing porphyrin ligands are another class of ruthenium imides well represented in the literature, also in a high oxidation state. 55−57 One of the few classes of terminal Ru imido complexes in low oxidations states is Steedman's imido-capped Ru(II) arenes (Chart 1).…”

Section: ■ Introductionmentioning

confidence: 99%

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Electronic and Structural Comparisons between Iron(II/III) and Ruthenium(II/III) Imide Analogs

et al. 2019

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To examine structural and electronic differences between iron and ruthenium imido complexes, a series of compounds was prepared with different phosphine basal sets. The starting material for the ruthenium complexes was Ru(NAr/Ar*)(PMe 3 ) 3 (Ru1/Ru1*), where Ar = 2,6-( i Pr) 2 C 6 H 3 and Ar* = 2,4,6-( i Pr) 3 C 6 H 2 , which were prepared from cis-RuCl 2 (PMe 3 ) 4 and 2 equiv of LiNHAr/Ar*. The starting materials for the iron complexes were the analogous Fe(NAr/Ar*)(PMe 3 ) 3 species (Fe1/Fe1*), which were not isolated but could be generated in situ from FeCl 2 , PMe 3 , and LiNHAr/Ar*. With both iron and ruthenium, the PMe 3 starting materials underwent phosphine replacement with chelating ligands to give new group 8 imido complexes in the +2 oxidation state. Addition of 1,2-bis(diphenylphosphino)ethane (dppe) to M1/M1* gave Ru(NAr/Ar*)(PMe 3 )(dppe) and Fe(NAr/ Ar*)(PMe 3 )(dppe). Addition of 1,2-bis(dimethylphosphino)ethane (dmpe) provided Ru(NAr/Ar*)(dmpe) 2 . A triphos ligand, {P(Me) 2 CH 2 } 3 Si t Bu ( t P 3 ), was also examined. Addition of t P 3 to Fe1 provided Fe(NAr)( t P 3 ) (Fe4), but a similar reaction with Ru1 only gave intractable materials. Oxidation of Fe4 with AgSbF 6 gave {Fe(NAr)( t P 3 )} + SbF 6 − (Fe4a). Oxidation of Ru2 with AgSbF 6 gave the unstable cation {Ru(NAr)(PMe 3 )(dppe)} + , which dimerized in the presence of acetonitrile via C−C bond formation at the aryl group C4 positions, affording {Ru(NAr)(PMe 3 )(NCMe)(dppe)} 2 + . This suggested that there was substantial radical character in the imide π system on oxidation and that an aromatic group substituted at the 4-position might provide greater stability. The cations {Fe(NAr*)(PMe 3 )(dppe)} + (Fe2a*), {Ru(NAr*)(PMe 3 )(dppe)} + (Ru2a*), and Fe4a were examined by EPR spectroscopy, which suggested differences in electronic structure depending on the metal and ligand set. CASPT2 calculations on model systems for Ru2a* and Fe2a* suggested that the large differences in electronic structure are related to the energy gap between the π-antibonding HOMO and the π-bonding HOMO-1. Both the geometry of the phosphines, which is slightly different between the iron and ruthenium analogs, and the metal center seem to contribute to this energetic difference.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Electronic and Structural Comparisons between Iron(II/III) and Ruthenium(II/III) Imide Analogs

et al. 2019

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“…The small free energy change calculated for the oxygen dissociation step can be compared to the evidence for moderate binding affinity of O 2 to (DMG) 2 ClRu(III). [46] In marked contrast, the oxo-porphyrin derivative 4, which has a similar N 4 -coordination sphere to DMG species 3, is calculated to have a very different energetic profile that features a relatively thermoneutral overall oxygen evolution reaction with fairly small energetic requirements for each individual step, including a moderate activation free energy for coupling (via OPBE). Although the origin of the differing energetic requirements of OER from 3 and 4 is not apparent to us, the (POR)ClRu(O) system appears to be one of the more promising candidates for accessible OER energetics and O 2 production.…”

Section: Dioxygen Dissociation From Dioxygen Complexes Lruà Omentioning

confidence: 97%

“…The intermediate dihedrals of the remaining species may be the result of balancing the steric (van der Waals) interactions between the ligands against repulsive interactions between lone electrons pairs of the peroxo oxygens, as in organic peroxides. [46] Generally, the coupling reactions of most of the RuÀ oxo complexes are calculated to be weakly to moderately exoergic (0 to À 20 kcal) or endoergic (0 to + 20 kcal), with the exception of the anionic complexes 2 (to 7) and 5 e (to 10 e) (Figure 11). These anionic species have very large positive free energy changes for coupling, ΔG coup = + 60-85 kcal/mol and are thus strongly disfavoured thermodynamically.…”

Section: Oà O Coupling and The Peroxo-bridged Complexesmentioning

confidence: 99%

“…Among the four-coordinate products the NTA derivative 20 a is constrained by its ligand to be trigonal pyramidal. The unconstrained AHA complex 17, however, optimizes in a square planar geometry, which is unusual for d 5 metals, but has been observed in Ru(II) [45] and Ru(IV) [46] compounds. In a liquid phase dissociation reaction a donor molecule like water could coordinate prior to or concerted with dioxygen dissociation, avoiding the typically unstable 4-coordinate LRu(III).…”

Section: Dioxygen Dissociation From Dioxygen Complexes Lruà Omentioning

confidence: 99%

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Structural Effects on Dioxygen Evolution from Ru(V)−Oxo Complexes

Swann

Nicholas

2021

Eur J Inorg Chem

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A series of ruthenium(V)À oxo compounds, LRu(V)O (n) [L = bipyridinedicarboxylate (BDA), alpha-hydroxycarboxylate (AHA), porphyrin (POR), dimethylglyoximate (DMG), and nitrilotriacetate (NTA); n = + 1,0, À 1] are evaluated by Density Functional Theory for their ability to produce dioxygen through coupling of Ru(V)À oxo species, bimetallic peroxides (LRu(IV)-OÀ OÀ Ru(IV) L), and dioxygen (LRu(IV)-O 2 ) complexes. Anionic RuÀ oxo complexes (AHA) 2 RuO À (2) and ( NTA)Ru(O)Cl À (5 e) have prohibitively large free energies of coupling, while neutral and monocationic species (1 b, 3-5 a-d) show small to moderate free energies of coupling. Transition states for OÀ O coupling were found for (NTA)RuO (5 a), (NTA)RuO(NH 3 ) (5 c), (NTA)RuO (Pyr) (5 d), (DMG) 2 ClRu(O) ( 8) and (POR)RuO(Cl) ( 9), yielding moderate activation energies in the range of 18-22 kcal/mol. The overall oxygen evolution reaction (OER) free energies decrease in favourability as the coordination number of LRuO decreases, i. e. 7 > 6 > 5. The modest activation energies and free energies along the reaction coordinate for (NTA)(L)RuO and (POR)ClRu(O) suggest that these species would undergo kinetically and thermodynamically favorable oxygen evolution.

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Heterometallic Iridium, Rhodium and Ruthenium Nitrido Complexes Supported by Oxygen and Sulfur Donor Ligands

Chong

Cheung

et al. 2022

Eur J Inorg Chem

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Heterometallic μ‐nitrido complexes have been synthesized from organometallic complexes containing O/S‐donor ligands and a ruthenium(VI) nitride. The treatment of [Ir(tpip)(L)2] (tpip−=[N(Ph2PO)2]−; L=cyclooctene (coe) or 2,6‐dimethylphenylisocyanide (xylNC)) and [Ir{N(iPr2PS)2}(coe)] with [Ru(LOEt)(N)Cl2] (LOEt−=[Co(η5‐C5H5){P(O)(OEt)2}3]−) (1) afforded [(L)(tpip)Ir(μ‐N)Ru(LOEt)Cl2] (L=coe (2) or xylNC (3)) and [(coe){N(iPr2PS)2}Ir(μ‐N)Ru(LOEt)Cl2] (4), respectively, in which the Ir−N(nitride) bonds show double bond character. The bonding in 2–4 can be described by two resonance forms: Ir(I)−N≡Ru(VI) and Ir(III)=N=Ru(IV). The treatment of [Ph4P][Ir(CO)2Cl2] with 1 afforded (PPh4)[(CO)Cl2Ir(μ‐N)Ru(LOEt)Cl2] (5) that reacted with [Tl(SR)] to give (PPh4)[(CO)(RS)2Ir(μ‐N)Ru(LOEt)Cl2] (R=xyl (6), C6F4H (7)). The reaction of [M(acac)(CO)2)] or [Ru(acac)2(coe)2] (acac−=acetylacetonate) with 1 gave [(CO)(acac)M(μ‐N)Ru(LOEt)Cl2] [M=Ir (8), Rh (9)] or [(H2O)(acac)2Ru(μ‐N)Ru(LOEt)Cl2] (10), whereas the treatment of [Ru(acac)2(MeCN)2] with 1‐azidoadamantane (AdN3) yielded a Ru(II) tetrazene complex, [Ru(acac)2(N4Ad2)] (11).

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A photochemical route to a square planar, ruthenium(iv)-bis(imide)

Abstract: A square planar Ru(iv) bis(imide) can be synthesized by photolysis of a tetrazene starting material.

Cited by 7 publications

References 16 publications

Electronic and Structural Comparisons between Iron(II/III) and Ruthenium(II/III) Imide Analogs

Electronic and Structural Comparisons between Iron(II/III) and Ruthenium(II/III) Imide Analogs

Structural Effects on Dioxygen Evolution from Ru(V)−Oxo Complexes

Heterometallic Iridium, Rhodium and Ruthenium Nitrido Complexes Supported by Oxygen and Sulfur Donor Ligands

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