[Ni0L]-Catalyzed Cyclodimerization of 1,3-Butadiene:  A Comprehensive Density Functional Investigation Based on the Generic [(C4H6)2Ni0PH3] Catalyst

Tobisch, Sven; Ziegler, Tom

doi:10.1021/ja012372t

Cited by 21 publications

(17 citation statements)

References 51 publications

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“…More broadly, the observation of oxidative cyclization with pyridine(diimine) ruthenium complexes where the chelate is redox innocent supports that access to triplet structures in so-called “two-state” reactivity is not a requirement for this C–C bond forming step. These results are consistent with other previously reported oxidative cyclizations with zirconium, − , nickel, − and platinum, in where the redox events are confined to the metal and the reaction proceeds exclusively on the S = 0 surface. Taken together, these oxidative cyclization studies pinpoint that the differentiating step facilitated by [(PDI)Fe] complexes in the intermolecular [2 + 2] cyclization event is the facile C(sp 3 )–C(sp 3 ) reductive elimination.…”

Section: Results and Discussionsupporting

confidence: 93%

Catalyst Design Principles Enabling Intermolecular Alkene-Diene [2+2] Cycloaddition and Depolymerization Reactions

et al. 2021

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Aryl-substituted pyridine(diimine) iron complexes promote the catalytic [2 + 2] cycloadditions of alkenes and dienes to form vinylcyclobutanes as well as the oligomerization of butadiene to generate divinyl(oligocyclobutane), a microstructure of poly(butadiene) that is chemically recyclable. A systematic study on a series of iron butadiene complexes as well as their ruthenium congeners has provided insights into the essential features of the catalyst that promotes these cycloaddition reactions. Structural and computational studies on iron butadiene complexes identified that the structural rigidity of the tridentate pincer enables rare s-trans diene coordination. This geometry, in turn, promotes dissociation of one of the alkene arms of the diene, opening a coordination site for the incoming substrate to engage in oxidative cyclization. Studies on ruthenium congeners established that this step occurs without redox involvement of the pyridine(diimine) chelate. Cyclobutane formation occurs from a metallacyclic intermediate by reversible C(sp3)–C(sp3) reductive coupling. A series of labeling experiments with pyridine(diimine) iron and ruthenium complexes support the favorability of accessing the +3 oxidation state to trigger C(sp3)–C(sp3) reductive elimination, involving spin crossover from S = 0 to S = 1. The high density of states of iron and the redox-active pyridine(diimine) ligand facilitate this reactivity under thermal conditions. For the ruthenium congener, the pyridine(diimine) remains redox innocent and irradiation with blue light was required to promote the analogous reactivity. These structure–activity relationships highlight important design principles for the development of next generation catalysts for these cycloaddition reactions as well as the promotion of chemical recycling of cycloaddition polymers.

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Section: Results and Discussionsupporting

confidence: 93%

Catalyst Design Principles Enabling Intermolecular Alkene-Diene [2+2] Cycloaddition and Depolymerization Reactions

et al. 2021

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“…Thus, the insertion into the metal-allyl bond occurs on an h 3 -coordinated allyl for both electron-rich and -poor metals (d 1 and d 0 ). [10][11][12] The free-enthalpy barrier for ethylene insertion into [La]-A C H T U N G T R E N N U N G (h 3 -C 4 H 7 ) is slightly lower (by 2.7 kcal mol À1 ) than that for the trans-1,4-insertion of butadiene (Figure 4 B vs. 3 A). Once again, this difference in energy is not significant within the precision of the method, but it does indicate a slight kinetic preference for ethylene insertion.…”

Section: Insertions Into the Allyl Complex [Cp*a C H T U N G T R E N mentioning

confidence: 99%

“…In an early study of butadiene and isoprene copolymerization catalyzed by [CpTiR] + (used as a model for CpTiCl 3 /MAO) (MAO = methylaluminoxane), it has been suggested, on the basis of Hartree-Fock geometry optimization, that the h 3 -allyl ligand goes toward h 1 -coordination during the reaction; this structural change is suggested to be rate determining. [9] Tobisch and co-workers have carried out numerous computational studies of butadiene oligomerization mostly catalyzed by electron-rich metal (Ni II ) complexes, [10,11] but also by CpTi III . [12] In all cases, insertion of butadiene occurs into an h 3 -allyl complex and not into an h 1 -allyl complex.…”

Section: Introductionmentioning

confidence: 99%

A Joint Experimental/Theoretical Investigation of the Statistical Olefin/Conjugated Diene Copolymerization Catalyzed by a Hemi‐Lanthanidocene [(Cp*)(BH₄)LnR]

Perrin

Bonnet

Chenal

et al. 2010

Chemistry A European J

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Statistical copolymerization of ethylene and isoprene was achieved by using a borohydrido half-lanthanidocene complex. Under copolymerization conditions, activation of [(Cp*)(BH(4))(2)Nd(thf)(2)] (Cp*=η(5)-C(5)Me(5)) by an appropriate alkylating agent affords trans-1,4-poly-isoprene-co-ethylene. Analysis of the microstructure of the copolymer revealed the presence of successive short sequences of ethylene/ethylene, trans-1,4-isoprene/ethylene, and trans-1,4-isoprene/trans-1,4-isoprene. A small amount of 1,2-insertion of isoprene was observed, and no cyclic structures within the chain were characterized. Test runs showed that these catalysts are unable to copolymerize α-olefins (such as hex-1-ene) with isoprene. The probable initial steps in the copolymerization have been computed at the DFT level of theory. Analysis of the energy profile provides insight into the catalyst's activity and selectivity. Our theoretical results highlight the key role played by the allyl intermediate, in which diene insertion, and to a lesser extent olefin insertion, is the rate-determining step of the process. These results also illustrate the coordination behavior of the allyl ligand during the insertion of an incoming monomer, which directly inserts, after pre-coordination to the metal center, into the η(3)-allyl ligand without inducing an η(3) to η(1) haptotropic shift. Finally, the inactivity of this family of catalysts towards the copolymerization of hex-1-ene was rationalized on the basis of the free-energy profile of the copolymerization.

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“…For example, nickellacycles similar to 6.41 are isolated and fully characterized [41g, 44f ]. Detailed computational mechanistic study have also been carried out [47].…”

Section: Cyclodimerization and Cyclotrimerization Of 13-butadienementioning

confidence: 99%

Cyclooligomerization and Cycloisomerization of Alkenes and Alkynes

Saito¹

2005

Modern Organonickel Chemistry

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Nickel-catalyzed cyclooligomerization and cycloisomerization reactions of alkenes and alkynes form the cornerstones of organic transition metal chemistry (Reppe, in the 1940s; see Section 6.3.1), and so far these have been among the main subjects studied extensively. In this chapter, nickel-catalyzed cyclooligomerization and cycloisomerization reactions will be described, as will certain nickel-mediated (stoichiometric) reactions, which are closely related to the catalytic reactions. Emphasis is placed on recent developments in nickel chemistry, as earlier studies have been repeatedly reviewed from several viewpoints [1-10]. Cyclization and cycloaddition reactions which involve the addition of other substrates (e.g., hydrosilanes, hydrostannanes and disilanes) will be described in other appropriate chapters in this monograph. 6.1 Cyclooligomerization of AlkenesIn nickel-catalyzed cyclooligomerization reactions of alkenes, strained compounds such as cyclopropenes, methylenecyclopropanes, and norbornadiene are normally used as the reactive substrates. The reactions may involve either the cleavage of the weakened carbon-carbon p bond -as is the case for many cyclooligomerization and cycloisomerization reactions -or the cleavage of the strained carbon-carbon s bond, which is followed by the formation of new carbon-carbon s bonds. Unstrained alkenes usually produce linear oligomers in the presence of nickel catalysts (see Chapter 3).Cyclopropenes are highly strained carbocyclic compounds. For example, the calculated strain energy of cyclopropene is 228 KJ mol À1 (54.5 Kcal mol À1 ) [10]. Accordingly, cyclopropenes are prone to undergo cyclooligomerization in the presence of a Ni catalyst. As an example, 3,3-dimethylcyclopropene provides cyclodimerization and cyclotrimerization products (Eq. (6.1)) [11a, b]. A generally accepted mechanism for this reaction is shown in Scheme 6.1, where the Ni(0) complex interacts with the p bond of the cyclopropene molecule and forms a Ni(0)-h 2 -olefin Modern Organonickel Chemistry. Edited by Y. Tamaru

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[Ni⁰L]-Catalyzed Cyclodimerization of 1,3-Butadiene: A Comprehensive Density Functional Investigation Based on the Generic [(C₄H₆)₂Ni⁰PH₃] Catalyst

Cited by 21 publications

References 51 publications

Catalyst Design Principles Enabling Intermolecular Alkene-Diene [2+2] Cycloaddition and Depolymerization Reactions

Catalyst Design Principles Enabling Intermolecular Alkene-Diene [2+2] Cycloaddition and Depolymerization Reactions

A Joint Experimental/Theoretical Investigation of the Statistical Olefin/Conjugated Diene Copolymerization Catalyzed by a Hemi‐Lanthanidocene [(Cp*)(BH₄)LnR]

Cyclooligomerization and Cycloisomerization of Alkenes and Alkynes

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[Ni0L]-Catalyzed Cyclodimerization of 1,3-Butadiene: A Comprehensive Density Functional Investigation Based on the Generic [(C4H6)2Ni0PH3] Catalyst

Cited by 21 publications

References 51 publications

Catalyst Design Principles Enabling Intermolecular Alkene-Diene [2+2] Cycloaddition and Depolymerization Reactions

Catalyst Design Principles Enabling Intermolecular Alkene-Diene [2+2] Cycloaddition and Depolymerization Reactions

A Joint Experimental/Theoretical Investigation of the Statistical Olefin/Conjugated Diene Copolymerization Catalyzed by a Hemi‐Lanthanidocene [(Cp*)(BH4)LnR]

Cyclooligomerization and Cycloisomerization of Alkenes and Alkynes

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[Ni⁰L]-Catalyzed Cyclodimerization of 1,3-Butadiene: A Comprehensive Density Functional Investigation Based on the Generic [(C₄H₆)₂Ni⁰PH₃] Catalyst

A Joint Experimental/Theoretical Investigation of the Statistical Olefin/Conjugated Diene Copolymerization Catalyzed by a Hemi‐Lanthanidocene [(Cp*)(BH₄)LnR]