Gas-phase Fe+-assisted cycloaddition reactions of cyclopentadiene with small alkenes and alkynes

Chen, Quan; Sioma, Cathy; Kan, Steven Z.; Freiser, Ben S.

doi:10.1016/s1387-3806(98)14076-9

Cited by 9 publications

(4 citation statements)

References 45 publications

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“…This indicates that the deuteron was not always involved in the transfer during fragmentation, depending on the ability of the product ion structures in the gas phase to facilitate such processes. Similar H/D behavior was observed by Freiser and co‐workers in the gas‐phase Fe + ‐assisted cycloaddition reactions of cyclopentadiene with alkenes and alkynes 20. As illustrated in Table 1, the product ion A is proposed to have two isomeric ion structures (A1 and A2) in the gas phase, where A1 loses and A2 retains the deuteron upon CID.…”

Section: Resultssupporting

confidence: 72%

Tandem mass spectrometry and hydrogen/deuterium exchange studies of protonated species of 1,1′‐bis(diphenylphosphino)‐ferrocene oxidative impurity generated during a Heck reaction

Hernández

Liu

et al. 2008

Rapid Comm Mass Spectrometry

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Oxidation of 1,1'-bis(diphenylphosphino)-ferrocene (DPPF) was found to occur when it served as the ligand for Pd(II)(CH3COO)2 in a Heck reaction. This oxidative impurity of DPPF, referred to as DPPF(O), was identified by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) and exact mass measurements. Protonated DPPF(O) exhibited unique fragmentation pathways in the gas phase. Hydrogen/deuterium (H/D) exchange experiments provided important insights into the dissociation mechanisms of protonated DPPF(O), suggesting the existence of isomeric structures of the product ions by retaining or losing a proton (or deuteron) upon collision-induced dissociation (CID). The specific fate of the proton (or deuteron) upon CID is postulated to be dependent on the distance between the exchangeable proton (or deuteron) and the sites of bond cleavage. Density functional theory (DFT) calculations at the B3LYP/LANL2DZ level of theory showed that oxygen in DPPF(O) plays a pivotal role in invoking pi-cation interactions between the p-type lone pair electrons (n pi) in oxygen and the anti-bonding orbital of Fe(II), accounting for the major fragmentation pathways of protonated DPPF(O). Facile formation of organometallic distonic ions in dissociation of protonated DPPF(O), and especially of protonated DPPF, could be useful for further exploration of their chemical properties by gas-phase ion/molecule reactions.

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Section: Resultssupporting

confidence: 72%

Tandem mass spectrometry and hydrogen/deuterium exchange studies of protonated species of 1,1′‐bis(diphenylphosphino)‐ferrocene oxidative impurity generated during a Heck reaction

Hernández

Liu

et al. 2008

Rapid Comm Mass Spectrometry

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“…Structure (d) was excluded by consideration of earlier work by Bakhtiar and Jacobson . Chen et al settled on (c) as the identity of FeC 7 H 8 + in eq 10. However, the present calculations suggest that (e) should be considered as a strong candidate.…”

Section: Resultsmentioning

confidence: 99%

“…It is also known that ligands can change the reactivity of a transition metal center. For example, the ligands C 5 H 5 and C 5 H 6 can bind tightly to a transition metal cation and alter the reactivity from the bare metal cation. − …”

Section: Introductionmentioning

confidence: 99%

Density Functional Study of the Retrocyclization of Norbornadiene and Norbornene Catalyzed by Fe⁺

McKee

2001

J. Am. Chem. Soc.

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In the presence of Fe(+) catalyst, the retro Diels-Alder reaction of norbornadiene (NBD) is predicted to be stepwise with an activation barrier of 18.8 kcal/mol, which is 3.1 kcal/mol lower than the concerted retro reaction. For norbornene (NBN), the Fe(+)-catalyzed retro reaction is also calculated to be stepwise with an activation barrier of 24.9 kcal/mol, which is 8.5 kcal/mol lower than the uncatalyzed stepwise reaction but 3.8 kcal/mol higher than the concerted reaction. The intermediates from the NBD and NBN retro Diels-Alder reactions, C(5)H(6)FeC(2)H(2)(+) and C(5)H(6)FeC(2)H(4)(+), are predicted to have low activation barriers for ligand-to-ligand hydrogen transfers (through an iron-hydrido intermediate) to form CpFeC(2)H(3)(+) and CpFeC(2)H(5)(+) and, ultimately, vinyl- and ethyl-substituted cyclopentadiene-iron complexes, respectively. In contrast to FeC(2)H(2)(+) and FeC(2)H(4)(+), the lowest-energy pathways on the C(5)H(6)FeC(2)H(2)(+) and C(5)H(6)FeC(2)H(4)(+) potential energy surfaces involve only one multiplicity (quartet). The C(2)H(2) and C(2)H(4) complexes of CpFe(+) and C(5)H(6)Fe(+) are compared.

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“…[16] FeC 5 There are many other reports of such activation of alcohols by metal ions, with elimination of water. [9] Classic ion-molecule reactions such as given by Equation (3), Equation (4), Equation (5), and Equation (6) correspond to "activation by ligand addition" (ALA), in which chemical modification of a ligand is induced by its association with a bare or ligated metal ion; in the case of Equation (6), the ligand (CH 3 ) 3 COH is activated by its addition to the Li + ion.…”

Section: Introductionmentioning

confidence: 99%

Activation of Gas‐Phase Uranyl Diacetone Alcohol Coordination Complexes by Spectator Ligand Addition

Ríos

Gibson

2012

Eur J Inorg Chem

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Gas-phase addition of a basic ligand to dipositive uranyl coordination complexes comprising diacetone alcohol (DAA) results in water-elimination, which indicates aldol dehydration of DAA to produce mesityl oxide. A novel attribute of the observed gas-phase chemistry is that a ligand exothermically associates to a coordination complex to provide the excitation required to induce chemistry in other ligands, with

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Gas-phase Fe+-assisted cycloaddition reactions of cyclopentadiene with small alkenes and alkynes

Cited by 9 publications

References 45 publications

Tandem mass spectrometry and hydrogen/deuterium exchange studies of protonated species of 1,1′‐bis(diphenylphosphino)‐ferrocene oxidative impurity generated during a Heck reaction

Tandem mass spectrometry and hydrogen/deuterium exchange studies of protonated species of 1,1′‐bis(diphenylphosphino)‐ferrocene oxidative impurity generated during a Heck reaction

Density Functional Study of the Retrocyclization of Norbornadiene and Norbornene Catalyzed by Fe⁺

Activation of Gas‐Phase Uranyl Diacetone Alcohol Coordination Complexes by Spectator Ligand Addition

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Gas-phase Fe+-assisted cycloaddition reactions of cyclopentadiene with small alkenes and alkynes

Cited by 9 publications

References 45 publications

Tandem mass spectrometry and hydrogen/deuterium exchange studies of protonated species of 1,1′‐bis(diphenylphosphino)‐ferrocene oxidative impurity generated during a Heck reaction

Tandem mass spectrometry and hydrogen/deuterium exchange studies of protonated species of 1,1′‐bis(diphenylphosphino)‐ferrocene oxidative impurity generated during a Heck reaction

Density Functional Study of the Retrocyclization of Norbornadiene and Norbornene Catalyzed by Fe+

Activation of Gas‐Phase Uranyl Diacetone Alcohol Coordination Complexes by Spectator Ligand Addition

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Density Functional Study of the Retrocyclization of Norbornadiene and Norbornene Catalyzed by Fe⁺