Carbon dioxide reduction by dinuclear Yb(<scp>ii</scp>) and Sm(<scp>ii</scp>) complexes supported by siloxide ligands

Willauer, Aurélien R.; Toniolo, Davide; Fadaei‐Tirani, Farzaneh; Yang, Yanming; Maron, Laurent; Mazzanti, Marinella

doi:10.1039/c9dt00554d

Cited by 34 publications

(18 citation statements)

References 79 publications

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“…The accessible molecular oxidation states of the lanthanides have rapidly expanded. − The synthesis and characterization of novel divalent complexes has enabled a detailed understanding of lanthanide electronic structure − and reactivity, − and, as a result, has demonstrated significant opportunities to improve our knowledge of the magnetic properties of the lanthanides. − Until 2019, molecular tetravalent lanthanide complexes were limited to cerium. − Recently developed weak-field ligand systems, such as imidophosphoranes [NP(NR 2 ) 3 ] − (R = alkyl), decrease the thermodynamic barrier for oxidation, thereby making the oxidation potential more accessible within the solvent window. , We have recently reported the synthesis and characterization of novel lanthanide complexes featuring weak-field dialkylamide imidophosphorane ligands. This class of compounds includes the most reducing Ce 3+ complex to date as well as one of the first isolable Tb 4+ complexes.…”

Section: Introductionmentioning

confidence: 99%

High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopic Analysis of Metal–Ligand Covalency in a 4f⁷ Valence Series (Eu²⁺, Gd³⁺, and Tb⁴⁺)

et al. 2021

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The recent isolation of molecular tetravalent lanthanide complexes has enabled renewed exploration of the effect of oxidation state on the single-ion properties of the lanthanide ions. Despite the isotropic nature of the 8S ground state in a tetravalent terbium complex, [Tb(NP(1,2-bis- t Bu-diamidoethane)(NEt2))4], preliminary X-band electron paramagnetic resonance (EPR) measurements on tetravalent terbium complexes show rich spectra with broad resonances. The complexity of these spectra highlights the limits of conventional X-band EPR for even qualitative determination of zero-field splitting (ZFS) in these complexes. Therefore, we report the synthesis and characterization of a novel valence series of 4f7 molecular complexes spanning three oxidation states (Eu2+, Gd3+, and Tb4+) featuring a weak-field imidophosphorane ligand system, and employ high-frequency and -field electron paramagnetic resonance (HFEPR) to obtain quantitative values for ZFS across this valence series. The series was designed to minimize deviation in the first coordination sphere from the pseudotetrahedral geometry in order to directly interrogate the role of metal identity and charge on the complexes’ electronic structures. These HFEPR studies are supported by crystallographic analysis and quantum-chemical calculations to assess the relative covalent interactions in each member of this valence series and the effect of the oxidation state on the splitting of the ground state and first excited state.

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Section: Introductionmentioning

confidence: 99%

High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopic Analysis of Metal–Ligand Covalency in a 4f⁷ Valence Series (Eu²⁺, Gd³⁺, and Tb⁴⁺)

et al. 2021

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“…Several systems have been discovered to date as affording stoichiometric formation of oxalates from CO 2 (one‐electron transfer followed by coupling), which may be regarded as a fundamental step of the naturally occurring photo‐synthesis . By using a Cu‐based system, this important reaction has even been carried out in a step‐by‐step catalytic mode .…”

Section: Methodsmentioning

confidence: 99%

Linear End‐On Coordination Modes of CO₂

2019

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The second case of linear end-on and evidence for an unprecedented bridging end-on coordination mode of CO 2 have been discovered for vanadium aryloxide complexes of the tetradentate ligand system (ONNO) 2À (ONNO = 2,4-Me 2-2-(OH) C 6 H 2 CH 2 ] 2 N(CH 2) 2 NMe 2). The reaction of divalent (ONNO)V II (TMEDA) with CO 2 and under the appropriate reaction conditions affords the trivalent (ONNO)V III (OH)(h 1-CO 2)r esulting from an intermediate CO 2 deoxygenation pathway followed by H-atom abstraction from the aromatic solvent, and CO 2 fixation. In contrast, the reduction of trivalent (ONNO)V III Cl(THF) with K, followed by exposure to CO 2 in ethereal solvent, afforded the dinuclear [(ONNO)V II ] 2 (m , h 1-CO 2).

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“…Here, we report the reduction of CS 2 by the dinuclear Yb II complex [Yb 2 L 4 ], 1 [L=(O t Bu) 3 SiO − ], which allowed to trap for the first time a product of CS coupling from CS 2 reduction in the complex [Yb 2 L 4 (C 2 S 2 )], 2 , together with the CS 2 2− bridged key intermediate [Yb 2 L 4 (CS 2 )], 3 .…”

Section: Figurementioning

confidence: 99%

“…[11] All the reported examples of CS 2 reduction by lanthanides involvet wo one-electron transfers by two metal complexes, but experimental and computational studies suggest that cooperative binding of the substrate by bimetallic intermediate is crucial in the outcomeo ft he reduction. [8c, 12] As such, the reaction of polynuclear lanthanide complexes with CS 2 is of interest because it may allow to trap reactive intermediates or stabilize unusualreactionproducts.Here, we report the reduction of CS 2 by the dinuclear Yb II complex [Yb 2 L 4 ], 1 [L = (OtBu) 3 SiO À ], [13] whicha llowed to trap for the first time ap roduct of CS coupling from CS 2 reduction in the complex [Yb 2 L 4 (C 2 S 2 )], 2,together with the CS 2 2À bridged key intermediate [Yb 2 L 4 (CS 2 )], 3.Crystals of the homoleptic complex 1,w ere obtained by recrystallization from n-hexane at À40 8Co ft he [Yb 2 L 4 (DME)] complex prepared as previously described for [Sm 2 L 4 (DME)]. [14] The solid-state structure of 1 is presentedi nF igure 1a nd showst he presence of ad imer in whicht wo Yb II ions are bridged by three oxygen atoms from three different siloxide ligands in an on-symmetric fashion.…”

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confidence: 99%

CS₂ Reductive Coupling to Acetylenedithiolate by a Dinuclear Ytterbium(II) Complex

Toniolo

Willauer

Andrez

et al. 2019

Chemistry A European J

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The activation of CS 2 is of interesti nabroad range of fields and, more particularly,i nt he context of creating new CÀCb onds. The reaction of the dinucleary tterbium(II)c omplex [Yb 2 L 4 ], 1,[ L = (OtBu) 3 SiO À ]w ith carbon disulfide led to the isolationo fu nprecedented reduction products. In particular, the crystallographic characterization of complex [Yb 2 L 4 (m-C 2 S 2 )], 2,p rovided the first example of an acetylenedithiolate ligand formed from metal reduction of CS 2 .C omputational studies indicated that this unprecedented reactivity can be ascribed to the unusual binding mode of CS 2 2À in the isolated "key intermediate" [Yb 2 L 4 (m-CS 2 )], 3,w hich resultsf rom the dinuclear nature of 1.The activation of CS 2 by transition metals is of interest fort he development of catalysts that can convert the CS 2 pollutant, largely used as feedstock in viscose industrial production, into less toxic or useful products. [1] Numerous studies have also been driven by its similarity to CO 2 ,apotential abundant and renewable source of carbona nd the possibility of creating new CÀCb onds. [2] Metal complexes of the d [2b, c, 3] and 5f block, [4, 2d, 5] have been shown to promote aw iderange of reactions, such as CS 2 reduction to CS 2 2À ,d isproportionation to CS 3 2À andC S, head-to-headr eductiveC ÀCc oupling to afford tetrathioxalate, head-to-tail reductive CÀSc oupling, or cleavage of one CÀSb ondl eadingt oC Sa nd sulfide complexes. Complete disassembly of the CS 2 molecule has also been reported in three cases. [1b, 6] Divalent lanthanide ions display ab road range of reactivity with small unreactivem olecules, [7] but only few examples of CS 2 activationhave been reported. CS 2 activation by lanthanide ions has so far resulted in CS 2 disproportionation or reductive CÀSo rC ÀCc oupling to afford thiocarbonate, thiooxalate and thioformyl carbonotrithioate [(SCSCS 2 ) 2À ]r espectively. [8] Very recently the first example of ar are CS 2 2À dianion trapped between two Yb III ions has also been reported. [9] CO reductivec oupling by samarium(II) and uranium(III) complexesh as been reported to afford ketene carboxylate and ynediolate OÀCCÀO 2À (which act as linear k 2 -O,O' bridging ligands), respectively. [10] In contrast, the formation of the acetylenedithiolate dianion analogue (SÀCCÀS) 2À from CS 2 or CS reductionh as never been reported. Acetylenedithiolate is of interest as ab ridging ligand because of its potentialt os upport electronic communication between metal centers,b ut, due to its low stability, only af ew acetylenedithiolatec omplexesh ave been so far reported. [11] All the reported examples of CS 2 reduction by lanthanides involvet wo one-electron transfers by two metal complexes, but experimental and computational studies suggest that cooperative binding of the substrate by bimetallic intermediate is crucial in the outcomeo ft he reduction. [8c, 12] As such, the reaction of polynuclear lanthanide complexes with CS 2 is of interest because it may allow to trap reactive intermedia...

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Carbon dioxide reduction by dinuclear Yb(ii) and Sm(ii) complexes supported by siloxide ligands

Abstract: Low-coordinate dinuclear lanthanide complexes supported by siloxides effect the reduction of carbon dioxide to both carbonate and oxalate, but the cooperative binding of CO2 to the two Ln(ii) cations in the dimer favours oxalate formation.

Cited by 34 publications

References 79 publications

High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopic Analysis of Metal–Ligand Covalency in a 4f⁷ Valence Series (Eu²⁺, Gd³⁺, and Tb⁴⁺)

High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopic Analysis of Metal–Ligand Covalency in a 4f⁷ Valence Series (Eu²⁺, Gd³⁺, and Tb⁴⁺)

Linear End‐On Coordination Modes of CO₂

CS₂ Reductive Coupling to Acetylenedithiolate by a Dinuclear Ytterbium(II) Complex

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Carbon dioxide reduction by dinuclear Yb(ii) and Sm(ii) complexes supported by siloxide ligands

Abstract: Low-coordinate dinuclear lanthanide complexes supported by siloxides effect the reduction of carbon dioxide to both carbonate and oxalate, but the cooperative binding of CO2 to the two Ln(ii) cations in the dimer favours oxalate formation.

Cited by 34 publications

References 79 publications

High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopic Analysis of Metal–Ligand Covalency in a 4f7 Valence Series (Eu2+, Gd3+, and Tb4+)

High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopic Analysis of Metal–Ligand Covalency in a 4f7 Valence Series (Eu2+, Gd3+, and Tb4+)

Linear End‐On Coordination Modes of CO2

CS2 Reductive Coupling to Acetylenedithiolate by a Dinuclear Ytterbium(II) Complex

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High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopic Analysis of Metal–Ligand Covalency in a 4f⁷ Valence Series (Eu²⁺, Gd³⁺, and Tb⁴⁺)

High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopic Analysis of Metal–Ligand Covalency in a 4f⁷ Valence Series (Eu²⁺, Gd³⁺, and Tb⁴⁺)

Linear End‐On Coordination Modes of CO₂

CS₂ Reductive Coupling to Acetylenedithiolate by a Dinuclear Ytterbium(II) Complex