Density Functional Study of Protonated, Acetylated, and Mercurated Derivatives of Ferrocene:  Mechanism of the Electrophilic Substitution Reaction

Mayor-López, María J.; Weber, Jacques; Mannfors, B.; Cunningham, Allan F.

doi:10.1021/om980218i

Cited by 41 publications

(33 citation statements)

References 37 publications

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“…The results in 1 and 2 are in contrast to the previous reports that two Cp rings of a ferrocene nearly adopt an eclipsed conformation (D5h) in the gas phase, 30,31 meanwhile, staggered Cp rings of a ferrocene (D5d) are in single crystals. 31,32 The structure for 3 contains two independent centrosymmetric dimers. One of these along with the anions is shown in Figure 5.…”

Section: Resultscontrasting

confidence: 99%

Investigation of Molecular Interactions in the Carboxylato Zn(II) and Cd(II) Macrocyclic Complexes

Kwag¹,

Jeong²,

Lough³

et al. 2010

Bulletin of the Korean Chemical Society

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Coordination polymers on the basis of the assembly of metal ion "connectors" and multidentate ligand "linkers" have been of great interest due to their intriguing architectures and versatile applications.1-9 Metallotetraazamacrocycles bearing equatorial amines coordinated to the central metal ions and axial sites opened for incoming "linkers" are good "connectors" as building blocks for the construction of coordination polymers. 10-15Among multidentate ligands, polycarboxylates have been widely used as "linkers" due to their versatile coordination modes toward metal ions. [16][17][18][19] An fdc (fdc = 1,1'-ferrocenedicarboxylate ion) ligand as a kind of polycarboxylates has attracted attention not only in the field of coordination chemistry but also in the field of organometallic chemistry. [20][21][22][23] During our efforts to explore the molecular interactions between metallomacrocycles and polycarboxylate ligands in zinc(II) and cadmium(II) tetraazamacrocycles containing bridging polycarboxylate ligands, we successfully synthesized and structurally characterized two 1D zinc(II) coordination polymers 1 and 2, where each ferrocenyl of bridging fdc ligands adopts different conformation, and a macrocyclic cadmium(II) dimer 3. Thus, two Cp (Cp = cyclopentadienyl) rings of fdc ligands in 1 are mutually staggered, whereas they are eclipsed in 2. The cadmium(II) cyclams with folded macrocycles are bridged by an oxalate ligand in 3. In this report we describe the details of the synthesis and structures of 1-3.

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Section: Resultscontrasting

confidence: 99%

Investigation of Molecular Interactions in the Carboxylato Zn(II) and Cd(II) Macrocyclic Complexes

Kwag¹,

Jeong²,

Lough³

et al. 2010

Bulletin of the Korean Chemical Society

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“…33 The reproduction for the Fe±Cp distance and the rotational barrier in ferrocene was used as a test for the adequate level of theory and the results were in accordance with previous studies of the mode of attack in substitution reactions for different types of electrophiles (Fig 7) ± soft electrophiles preferred an endo attack where the electrophile was ®rst coordinated to the metal, before attacking the ring, whereas hard electrophiles directly attacked the ring (exo-attack). The potential energy surface for protonation was found to be very shallow, indicative of an equilibrium between ring and metal protonation.…”

Section: ±30supporting

confidence: 80%

“…For metallocenes, the metal±cyclopentadienyl ligand distance has been identi®ed as an appropriate test to determine the suitability of a calculation for the problem studied 32 and the large number of structural investgations available for ferrocenes often makes this the model compound of choice. 33 A summary of the calculated geometries for ferrocene is presented in Table 2.…”

Section: ±30mentioning

confidence: 99%

Organometallic molecular modelling - the computational chemistry of metallocenes: a review

Fey

1999

J. Chem. Technol. Biotechnol.

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The application of ab initio, density functional theory and molecular mechanical methods to the modelling of metallocenes, particularly ferrocene, is reviewed. Approaches to the representation of the metal-ring p-bonding in molecular mechanics and the quality of computed results from ab initio and density functional theory serve to illustrate the utility of modelling studies in organometallic chemistry.

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“…This contrasts with the Friedel-Crafts acetylation of ferrocene in which exo-attack of the acylium ion has been experimentally demonstrated (Scheme 12.3, path b) [11]. A theoretical study supports these contrasting pathways for Hg 2 þ as a representative soft electrophile, and the acylium ion as a representative hard electrophile [12]. Although the palladation of ferrocene does not appear to have been the subject of a mechanistic investigation, the corresponding reaction of benzene derivatives has been the subject of several studies.…”

Section: Asymmetric Synthesis Of Planar Chiral Metallocyclic Complexesmentioning

confidence: 93%

Metallocyclic Ferrocenyl Ligands

Richards

2009

Chiral Ferrocenes in Asymmetric Catalysis

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This chapter is a comprehensive account of the synthesis and application of planar chiral ferrocene-based metallocycles. The first examples of the asymmetric synthesis of this class of compound date from the late 1970s, with the pioneering work of Viatcheslav Sokolov. However, it is only since the millennium that they have found widespread application, principally as catalysts for the allylic imidate rearrangement initially developed by Larry Overman.In the vast majority of cases the metal of the metallocyclic ring is palladium. Thus this class of compound is a sub-category of palladacycles [1] and/or metallacycles [2] in which the metal is bonded to an sp 2 , or less frequently, an sp 3 carbon atom. A significant feature of anionic bidentate ferrocenyl ligands is that the complexed metal M becomes a direct component of the element of planar chirality displayed by the resultant complex (Scheme 12.1). This contrasts to the majority of neutral bidentate ferrocene ligands [3] (e.g., P-P, P-N etc.), where the complexed metal is more remote from the basis of chirality [4]. Where M ¼ Pd(II) or Pt(II), the ancillary ligands L 1 and L 2 of the resultant square-planar complex are distinguished by the larger trans-influence/effect of the anionic carbon ligand compared to the neutral heteroatom (X) ligand component. This is revealed by the longer L 1 -M bond length compared to the corresponding L 2 -M bond length where L 1 ¼ L 2 1) , and also by analysis of the kinetic and thermodymanic products arising from ligand substitution [5]. The coordination axis perpendicular to the square plane, as represented by diastereotopic ligands L 3 and L 4 , is significantly influenced by the bulk of the metallocene. Thus associative ligand substitution reactions of square-planar complexes will most likely involve approach of the incoming ligand from the top face (L 3 ).

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Density Functional Study of Protonated, Acetylated, and Mercurated Derivatives of Ferrocene: Mechanism of the Electrophilic Substitution Reaction

Cited by 41 publications

References 37 publications

Investigation of Molecular Interactions in the Carboxylato Zn(II) and Cd(II) Macrocyclic Complexes

Investigation of Molecular Interactions in the Carboxylato Zn(II) and Cd(II) Macrocyclic Complexes

Organometallic molecular modelling - the computational chemistry of metallocenes: a review

Metallocyclic Ferrocenyl Ligands

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