Neodymium(III) Complexes Capable of Multi‐Electron Redox Chemistry

Coughlin, Ezra J.; Zeller, Mat­thias; Bart, Suzanne C.

doi:10.1002/anie.201705423

Cited by 39 publications

(42 citation statements)

References 25 publications

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“…To obtain more information about the chemistry of Ln‐in‐crypt complexes in general, we have investigated reactions of lanthanide triflates with crypt. We report here that lanthanide triflates, Ln III (OTf) 3 (Ln=Nd, Sm), form isolable Ln III ‐in‐crypt complexes that are soluble in THF, the solvent commonly used for KC 8 reductions . Reduction of these Ln III complexes with KC 8 demonstrates that chemical transformations of Ln III ‐in‐crypt to Ln II ‐in‐crypt are possible with crystallographically‐characterized precursors and products.…”

Section: Introductionmentioning

confidence: 89%

Synthesis of Ln^II‐in‐Cryptand Complexes by Chemical Reduction of Ln^III‐in‐Cryptand Precursors: Isolation of a Nd^II‐in‐Cryptand Complex

et al. 2020

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Lanthanide triflates have been used to incorporate NdIII and SmIII ions into the 2.2.2‐cryptand ligand (crypt) to explore their reductive chemistry. The Ln(OTf)3 complexes (Ln=Nd, Sm; OTf=SO3CF3) react with crypt in THF to form the THF‐soluble complexes [LnIII(crypt)(OTf)2][OTf] with two triflates bound to the metal encapsulated in the crypt. Reduction of these LnIII‐in‐crypt complexes using KC8 in THF forms the neutral LnII‐in‐crypt triflate complexes [LnII(crypt)(OTf)2]. DFT calculations on [NdII(crypt)]2+], the first NdII cryptand complex, assign a 4f4 electron configuration to this ion.

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Section: Introductionmentioning

confidence: 89%

Synthesis of Ln^II‐in‐Cryptand Complexes by Chemical Reduction of Ln^III‐in‐Cryptand Precursors: Isolation of a Nd^II‐in‐Cryptand Complex

et al. 2020

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“…For example Bart and co‐workers exploited the multi‐electron redox chemistry of 4,6‐di‐ tert ‐butyl‐2‐[(2,6‐diisopropylphenyl)imino]quinone ( dipp iq 0 ), with access to the iminosemiquinone ( dipp isq .− ) and amidophenolate ( dipp ap 2− ) states, to isolate a family of Nd III complexes, all exhibiting distinctly different colors: [NdI 3 ( dipp iq 0 ) 2 ] ( 54 ), [Nd( dipp isq .− ) 2 I(THF)] ( 55 ), and [K(18‐crown‐6)][Nd( dipp ap) 2 (THF) 2 ] ( 56 ) (Figure 13). [105] The reverse multi‐electron oxidation of 56 , containing the amidophenolate ( dipp ap) ligand, was tested for its capacity to act as an electron store for future reductants using elemental chalcogens (S 8 and Se), with formation of the isoquinone state (via two one‐electron oxidations) accompanied by isolation of the S 5 and Se 5 complexes [105a] . As well as for the implications for catalysis and reaction chemistry, understanding how ligand‐centered redox events can modulate the photophysical and magnetic properties of lanthanoid complexes is of interest for extending the capabilities of optically or magnetically functional lanthanoid materials.…”

Section: Lanthanoid(iii) Complexes With Redox‐active Ligandsmentioning

confidence: 99%

“…with ligands in iq ( 54 ), isq ( 55 ) and ap ( 56 ) forms. Images of colored solutions (THF) reprinted with permission [105a] . Copyright (2017) Wiley‐VCH GmbH.…”

Section: Lanthanoid(iii) Complexes With Redox‐active Ligandsmentioning

confidence: 99%

Lanthanoid Complexes as Molecular Materials: The Redox Approach

Hay

Boskovic

2021

Chemistry A European J

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The development of molecular materials with novel functionality offers promise for technological innovation. Switchable molecules that incorporate redox‐active components are enticing candidate compounds due to their potential for electronic manipulation. Lanthanoid metals are most prevalent in their trivalent state and usually redox‐activity in lanthanoid complexes is restricted to the ligand. The unique electronic and physical properties of lanthanoid ions have been exploited for various applications, including in magnetic and luminescent materials as well as in catalysis. Lanthanoid complexes are also promising for applications reliant on switchability, where the physical properties can be modulated by varying the oxidation state of a coordinated ligand. Lanthanoid‐based redox activity is also possible, encompassing both divalent and tetravalent metal oxidation states. Thus, utilization of redox‐active lanthanoid metals offers an attractive opportunity to further expand the capabilities of molecular materials. This review surveys both ligand and lanthanoid centered redox‐activity in pre‐existing molecular systems, including tuning of lanthanoid magnetic and photophysical properties by modulating the redox states of coordinated ligands. Ultimately the combination of redox‐activity at both ligands and metal centers in the same molecule can afford novel electronic structures and physical properties, including multiconfigurational electronic states and valence tautomerism. Further targeted exploration of these features is clearly warranted, both to enhance understanding of the underlying fundamental chemistry, and for the generation of a potentially important new class of molecular material.

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“…However, the use of redox-active ligands to promote electron transfer in f element compounds and in uranium chemistry ,, in particular remains significantly rarer than in d block chemistry. − …”

Section: Introductionmentioning

confidence: 99%

Carbon Dioxide Reduction by Multimetallic Uranium(IV) Complexes Supported by Redox-Active Schiff Base Ligands

et al. 2020

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The synthesis, structure, and reactivity with CO 2 and CS 2 of new U(IV) complexes with a redox-active Schiff base are reported. The reaction of UI 3 with the heptadentate Schiff base ligand 2,2′,2″-tris(salicylideneimino)triethylamine (trensal) did not lead to the formation of a U(III) complex but to the reductive coupling and C−C bond formation between two imino groups of the Schiff base, yielding the U(IV) complex [U 2 (bis-trensal)], 1. Further reduction of 1 led to the dinuclear macrocyclic complex [{K(THF) 3 } 2 U 2 (cyclotrensal)], 3-THF, through a second C−C bond formation reaction between two additional imino groups. Complexes 1 and 3 are oxidized by AgOTf resulting in the cleavage of the C−C bonds and leading to the formation of the U(IV) complex [U(trensal)]OTf, 2. Complex 1 does not reduce CO 2 or CS 2 but undergoes insertion of CO 2 into one of the U−N bonds. In contrast, the reaction of 3 with 2 equiv of CO 2 leads to the reductive disproportionation of CO 2 to afford carbonate in 80% yield. In the presence of a large excess of CO 2 multiple reactions take place, as supported by the isolation of the crystals of [{K(THF) 3 }U 2 (μ-O)(CO 2 −CO-cyclo-trensal)(U(trensal))], 4. The higher reductive activity toward CO 2 of complex 3 compared to previously reported U(IV) complexes of reduced Schiff bases is interpreted in terms of its redox properties.

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Neodymium(III) Complexes Capable of Multi‐Electron Redox Chemistry

Cited by 39 publications

References 25 publications

Synthesis of Ln^II‐in‐Cryptand Complexes by Chemical Reduction of Ln^III‐in‐Cryptand Precursors: Isolation of a Nd^II‐in‐Cryptand Complex

Synthesis of Ln^II‐in‐Cryptand Complexes by Chemical Reduction of Ln^III‐in‐Cryptand Precursors: Isolation of a Nd^II‐in‐Cryptand Complex

Lanthanoid Complexes as Molecular Materials: The Redox Approach

Carbon Dioxide Reduction by Multimetallic Uranium(IV) Complexes Supported by Redox-Active Schiff Base Ligands

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Neodymium(III) Complexes Capable of Multi‐Electron Redox Chemistry

Cited by 39 publications

References 25 publications

Synthesis of LnII‐in‐Cryptand Complexes by Chemical Reduction of LnIII‐in‐Cryptand Precursors: Isolation of a NdII‐in‐Cryptand Complex

Synthesis of LnII‐in‐Cryptand Complexes by Chemical Reduction of LnIII‐in‐Cryptand Precursors: Isolation of a NdII‐in‐Cryptand Complex

Lanthanoid Complexes as Molecular Materials: The Redox Approach

Carbon Dioxide Reduction by Multimetallic Uranium(IV) Complexes Supported by Redox-Active Schiff Base Ligands

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Synthesis of Ln^II‐in‐Cryptand Complexes by Chemical Reduction of Ln^III‐in‐Cryptand Precursors: Isolation of a Nd^II‐in‐Cryptand Complex

Synthesis of Ln^II‐in‐Cryptand Complexes by Chemical Reduction of Ln^III‐in‐Cryptand Precursors: Isolation of a Nd^II‐in‐Cryptand Complex