Bimetallic cooperation across the periodic table

Campos, Jesús

doi:10.1038/s41570-020-00226-5

“…Molecules featuring metal-metal (M-M) bonds first received significant attention with regard to the nature of the intermetallic bonding, [1][2][3][4][5][6] but have now grown into a vigorous field including applications as catalysts for organic transformations. [7,8] There are also a number of cofactors of metalloenzymes that have two metals within range of forming M-M bonds (< 3 Å).…”

Section: Introductionmentioning

confidence: 99%

Spin States, Bonding and Magnetism in Mixed‐Valence Iron(0)‐Iron(II) Complexes**

Kim

¹

,

Wilson

²

,

Fataftah

³

et al. 2022

Chemistry A European J

6

1

0

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We report the synthesis of two complexes featuring unsupported Fe-Fe bonds, L x Fe-Fp (L a = 3-methyl-2,4-bis(2,6-dimethylphenylimido)pentyl, L b = 1,3-bis (2,4,6trimethylphenylimido)propyl; Fp = Fe(CO)2Cp). Mössbauer spectroscopy, SQUID magnetometry and computational analysis indicate that the most accurate electronic structure description is LFe II -Fe 0 (CO)2Cp, in which the Fe(CO)2Cp is low spin iron(0) and acts as a Lewis base toward the high spin iron(II) of the LFe fragment which is a Lewis acid. In both compounds, the three-coordinate high-spin iron(II) site has large zero-field splitting (zfs), up to D = -50 cm -1 .

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“… 31 , 32 In contrast, the remarkable acceleration observed for C–C coupling in compounds 4 compared to 1 seems to be the result of stabilization of key intermediates by the presence of aurophilic interactions combined with the Lewis acidic character of [Au(PR 2 Ar′)] + that enables phosphine migration, thus representing an example of rate acceleration by polymetallic entities compared to monometallic counterparts. 65 − 67 …”

Section: Resultsmentioning

confidence: 99%

Reductive C–C Coupling from Molecular Au(I) Hydrocarbyl Complexes: A Mechanistic Study

Miranda-Pizarro

¹

,

Luo

²

,

Moreno

³

et al. 2021

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Organometallic gold complexes are used in a range of catalytic reactions, and they often serve as catalyst precursors that mediate C–C bond formation. In this study, we investigate C–C coupling to form ethane from various phosphine-ligated gem-digold(I) methyl complexes including [Au 2 (μ-CH 3 )(PMe 2 Ar′) 2 ][NTf 2 ], [Au 2 (μ-CH 3 )(XPhos) 2 ][NTf 2 ], and [Au 2 (μ-CH 3 )( t BuXPhos) 2 ][NTf 2 ] {Ar′ = C 6 H 3 -2,6-(C 6 H 3 -2,6-Me) 2 , C 6 H 3 -2,6-(C 6 H 2 -2,4,6-Me) 2 , C 6 H 3 -2,6-(C 6 H 3 -2,6- i Pr) 2 , or C 6 H 3 -2,6-(C 6 H 2 -2,4,6- i Pr) 2 ; XPhos = 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl; t BuXPhos = 2-di- tert -butylphosphino-2′,4′,6′-triisopropylbiphenyl; NTf 2 = bis(trifluoromethyl sulfonylimide)}. The gem-digold methyl complexes are synthesized through reaction between Au(CH 3 )L and Au(L)(NTf 2 ) {L = phosphines listed above}. For [Au 2 (μ-CH 3 )(XPhos) 2 ][NTf 2 ] and [Au 2 (μ-CH 3 )( t BuXPhos) 2 ][NTf 2 ], solid-state X-ray structures have been elucidated. The rate of ethane formation from [Au 2 (μ-CH 3 )(PMe 2 Ar′) 2 ][NTf 2 ] increases as the steric bulk of the phosphine substituent Ar′ decreases. Monitoring the rate of ethane elimination reactions by multinuclear NMR spectroscopy provides evidence for a second-order dependence on the gem-digold methyl complexes. Using experimental and computational evidence, it is proposed that the mechanism of C–C coupling likely involves (1) cleavage of [Au 2 (μ-CH 3 )(PMe 2 Ar′) 2 ][NTf 2 ] to form Au(PR 2 Ar′)(NTf 2 ) and Au(CH 3 )(PMe 2 Ar′), (2) phosphine migratio...

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“…Controlling the electronic coupling of individual transition metal centers as a function of their interatomic separation, relative orientation, and charge over sub-nanometer length scales has been a long-standing aspiration and research objective in fields ranging from spintronics to catalysis and optoelectronics. [1] A fundamental understanding of the electronic structure of small multinuclear metal complexes, their structure-property relationship and dependence on metal centers separation (relative orientation and charge) enables cooperative effects to be precisely tuned which could ultimately translate into their catalytic, magnetic, and optical properties. [2] Inspired by precise control and efficiency of metalloenzymes evidenced in biological systems that possess more than one metal center (e. g., the homobimetallic catechol oxidase (CuÀ Cu); [3] methane monooxygenase (FeÀ OÀ Fe); [4] (MnÀ Mn) containing arginase; [5] or heterobimetallic metalloenzymes phosphatase (Fe-Zn); [6] and CO dehydrogenase (NiÀ Fe), [7] synthetic chemists by mimicking biological principles as a model have prepared a diverse library of multinuclear complexes that leverage metal-metal cooperativity.…”

Section: Introductionmentioning

confidence: 99%

“…Controlling the electronic coupling of individual transition metal centers as a function of their interatomic separation, relative orientation, and charge over sub‐nanometer length scales has been a long‐standing aspiration and research objective in fields ranging from spintronics to catalysis and optoelectronics. [1] A fundamental understanding of the electronic structure of small multinuclear metal complexes, their structure‐property relationship and dependence on metal centers separation (relative orientation and charge) enables cooperative effects to be precisely tuned which could ultimately translate into their catalytic, magnetic, and optical properties. [2] …”

Section: Introductionmentioning

confidence: 99%

Metal‐to‐Metal Distance Modulation by Ligand Design: A Case Study of Structure‐Property Correlation in Planar Chiral Cyclophanyl Metal Complexes

Hassan

¹

,

Bräse

²

2021

Chemistry A European J

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Multinuclear metal complexes have seen tremendous progress in synthetic advances, their versatile structural features, and emerging applications. Here, we conceptualize Metal-to-Metal distance modulation in cyclophanyl metal complexes by bridging ligand design employing the cofacially stacked cyclophanyl-derived pseudo-geminal, -ortho, -meta, and -para constitutional isomers grafted with N-, O-, and P-containing chelates that allow the installation of diverse (hetero)metallic moieties in a distance-defined and spatially-oriented relation to one another. Metal-to-Metal distance modulation and innate transannular "through-space" π-π electronic interactions via the co-facially stacked benzene rings in cyclophanyl-derived complexes as well as their specific stereochemical structural features (element of planar chirality) are crucial factors that contribute to the tuning of structure-property relationships, which stand at the very center from the perspective of cooperative effects in catalysis as well as emerging material applications.

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Bimetallic cooperation across the periodic table

Cited by 174 publications

References 89 publications

Spin States, Bonding and Magnetism in Mixed‐Valence Iron(0)‐Iron(II) Complexes**

Spin States, Bonding and Magnetism in Mixed‐Valence Iron(0)‐Iron(II) Complexes**

Reductive C–C Coupling from Molecular Au(I) Hydrocarbyl Complexes: A Mechanistic Study

Metal‐to‐Metal Distance Modulation by Ligand Design: A Case Study of Structure‐Property Correlation in Planar Chiral Cyclophanyl Metal Complexes

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