Reactivity of Organothorium Complexes with TEMPO

Langeslay, Ryan R.; Walensky, Justin R.; Evans, William J.

doi:10.1021/ic501034b

Cited by 24 publications

(27 citation statements)

References 46 publications

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“…The Th1-C1 bond length in 2 is 2.65(2) Å, which is longer than that reported for Th IV -Me bond average (2.53 Å) in metallocene-like complexes. 16,18,27,[30][31][32][33][34][35][36] The An-C1 bond lengths in 3·LiCl, average 2.532 (5)…”

Section: Synthesis Of [M(l -2h )An(r)]mentioning

confidence: 99%

Thorium(IV) and Uranium(IV) trans-Calix[2]benzene[2]pyrrolide Alkyl and Alkynyl Complexes: Synthesis, Reactivity, and Electronic Structure

et al. 2017

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2017) Thorium(IV) and uranium(IV) transcalix[2]benzene[2]pyrrolide alkyl and alkynyl complexes: synthesis, reactivity, and electronic structure. ABSTRACT: The first thorium(IV) and uranium(IV) hydrocarbyl complexes of a trans-calix[2]benzene[2]pyrrolide macrocycle can use ligand non-innocence to enable multiple C-H bond activation reactions at the metal. Both alkyl and alkynyl complexes supported by the (L) dianion and (L -2H ) tetraanion are reported. The Th IV and U IV mono-alkyl -ate complexes [M(L -2H )An(R)] (M = K for R = CH2Ph, M = Li for R = Me, CH2SiMe3), in which the ligand aryl groups are metallated, add the C-H bonds of terminal alkynes across the metal and ligand, forming the An IV -alkynyl complexes [(L)An(C≡CR')2] (R' = SiMe 3 , Si i Pr 3 ). This ligand reprotonation from (L -2H ) 4to (L) 2is accompanied by a change in coordination mode of the ligand from η 5 :η 5 to η 5 :η 1 :η 5 :η 1 . Alternatively, the original alkyl group can be retained if the ligand is reprotonated using [Et3NH][BPh4], affording the Th IV cations [(L)Th(R)][BPh4] (R = CH2Ph, N(SiMe3)2). Again, ligand rearrangement to the κ 1 :η 6 :κ 1 :η 6 coordination mode occurs. These complexes provide rare examples of bis(arene) actinide sandwich geometry. The two η 1 -alkynides in [(L)Th(C≡CSiMe 3 ) 2 ] rearrange upon coordination of [Ni 0 ], forming [(L)Th(C≡CSiMe 3 ) 2 ·Ni(PR'' 3 )] (R'' = phenyl, cyclohexyl) -featuring the shortest yet reported distance between Th and Ni, and giving unprecedented insight into the changes in macrocyclic ligand coordination between κ 1 :η 6 :κ 1 :η 6 and η 5 :η 5 coordination modes. A computational study of this conformational change demonstrates the η 5 :η 5 coordination mode to be the more stable in the Th/Ni bimetallics (and hypothetical Pt analogues), an observation rationalised by detailed analysis of the Kohn-Sham orbital structure of the κ 1 :η 6 :κ 1 :η 6 and η 5 :η 5 conformers. Although remarkably inert to even high-pressures of CO 2 at room temperature, the bis(alkynyl) complexes [(L)An(C≡CSiMe 3 ) 2 ] completely cleave one CO bond of CO 2 when heated under a 1 bar pressure, resulting in the formation, and elimination from the metal, of a new, CO-inserted, bicyclic, carbonylated macrocycle with complete control over the C-C and C-N bond forming reactions. Scheme 2. Syntheses of [M(L -2H )Th(R)] (R = Me (2), CH 2 SiMe 3 (3), CH 2 Ph (4) and [M(L -2H )U(R)] (R = Me (5), CH 2 SiMe 3 (6), CH 2 Ph (7)).

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Section: Synthesis Of [M(l -2h )An(r)]mentioning

confidence: 99%

Thorium(IV) and Uranium(IV) trans-Calix[2]benzene[2]pyrrolide Alkyl and Alkynyl Complexes: Synthesis, Reactivity, and Electronic Structure

et al. 2017

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“…of TEMPO to form 1-(2-propen-1-yloxy)-2,2,6,6-tetramethylpiperidine (allyl-TEMPO) and Cp * 2 Th(η 1 -C 3 H 5 )(η 1 -TEMPO) (Scheme 159). [155] M a n u s c r i p t M a n u s c r i p t 136 In contrast, Cp * 2 ThBr 2 reacted with 2 equiv. of TEMPO by loss of C 5 Me 5 to form dimeric (C 5 Me 5 ) 2 and (η 2 -TEMPO) 2 ThBr 2 , in which the TEMPO -anions bind through oxygen and nitrogen.…”

Section: Other Organolanthanide-catalyzed Reactionsmentioning

confidence: 98%

“…Towever, a bis(TEMPO) metallocene, Cp * 2 Th(η 1 -TEMPO) 2 , was accessible from the reaction of [Cp * 2 ThH 2 ] 2 with 4 equiv. of TEMPO (Scheme 160) [155]. …”

mentioning

confidence: 99%

“…of KC 8 , while ThBr 4 (THF) 4 reacted with TEMPO alone to form ThBr 4 (THF) 2 (η 1 -TEMPO), which contains an oxygen-bound TEMPO radical. Scheme 161 summarizes these reactions [155]. Scheme 161.…”

mentioning

confidence: 99%

“…Scheme 161. Formation of (η 2 -TEMPO) 2 ThBr 2 , Th(η 1 -TEMPO) 2 (η 2 -TEMPO) 2 , and ThBr 4 (THF) 2 (η 1 -TEMPO).Finally, the purple Th 3+ complex (C 5 Me 4 H)3 Th could be oxidized in the presence of TEMPO, without ligand loss, to afford the colorless Th 4+ species (C 5 Me 4 H)3 Th(η 1 -TEMPO) according to Scheme 162 [155]. Scheme 162.…”

mentioning

confidence: 99%

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Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2014

Edelmann

2016

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Uncovering Factors Controlling Reactivity of Metal‐TEMPO Reaction Systems in the Solid State and Solution

Budny‐Godlewski,

Piekarski,

Justyniak

et al. 2024

Chemistry A European J

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Nitroxides find application in various areas of chemistry, and a more in‐depth understanding of factors controlling their reactivity with metal complexes is warranted to promote further developments. Here, we report on the effect of the metal centre Lewis acidity on both the distribution of the O‐ and N‐centered spin density in 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) and turning TEMPO from the O‐ to N‐radical mode scavenger in metal‐TEMPO systems. We use Et(Cl)Zn/TEMPO model reaction system with tuneable reactivity in the solid state and solution. Among various products, a unique Lewis acid‐base adduct of Cl2Zn with the N‐ethylated TEMPO was isolated and structurally characterised, and the so‐called solid‐state 'slow chemistry' reaction led to a higher yield of the N‐alkylated product. The revealed structure‐activity/selectivity correlations are exceptional yet are entirely rationalised by the mechanistic underpinning supported by theoretical calculations of studied model systems. This work lays a foundation and mechanistic blueprint for future metal/nitroxide systems exploration.

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Reactivity of Organothorium Complexes with TEMPO

Cited by 24 publications

References 46 publications

Thorium(IV) and Uranium(IV) trans-Calix[2]benzene[2]pyrrolide Alkyl and Alkynyl Complexes: Synthesis, Reactivity, and Electronic Structure

Thorium(IV) and Uranium(IV) trans-Calix[2]benzene[2]pyrrolide Alkyl and Alkynyl Complexes: Synthesis, Reactivity, and Electronic Structure

Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2014

Uncovering Factors Controlling Reactivity of Metal‐TEMPO Reaction Systems in the Solid State and Solution

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