Theory of Ferrocenyl Compounds

Abstract

The aim of this chapter is to introduce the basic knowledge necessary to understand the electronic structure of ferrocenyl compounds. Molecular orbitals analysis is presented first, followed by a more contemporary description by density functional theory or elaborated ab initio calculations. In order to correlate computational results with experimental data, recent theoretical analysis of vibrational and Mössbauer spectroscopy, redox and excited states, are summarized. Due to numerous applications in non‐linear optics, calculated properties of ferrocenyl compounds in this field are presented. Catalytic and biological processes involving derivatives of ferrocenyl compounds have been studied from a theoretical point of view and are reviewed here. Ferrocenyl compounds are often used as a building block for constructing bigger chemical systems; simulation of large systems is a challenge, especially when involving metallic compounds. Nevertheless, some theoretical studies hav been done in that field (e.g. nanoparticles decorated with ferrocene or ferrocenyl compounds grafted onto gold surfaces) and are discussed in this chapter.

Twisted and Bent Out of Shape: Symmetry and Chirality Analysis of Substituted Ferrocenes

“…6 Theoretical chemists are also interested in ferrocene, and have described its electronic structure, geometrical parameters, physical properties, and reactivity. 7 From the beginning, the symmetry of ferrocene was a central issue in its structural exploration. Two main conformers were predicted: the D 5 h eclipsed conformer (I) and the D 5 d staggered conformer (II) (Figure 1).…”

“…The remarkable stability of ferrocene inspired the synthesis of many more “sandwich” complexes . Theoretical chemists are also interested in ferrocene, and have described its electronic structure, geometrical parameters, physical properties, and reactivity …”

Dissociation Dynamics and Electronic Structures of Highly Excited Ferrocenium Ions Studied by Femtosecond XUV Absorption Spectroscopy

“…From a molecular orbital point of view, it is perhaps not surprising that FeCp 2 + and Fe + possess similar spectra. The frontier orbitals of ferrocene are nonbonding d orbitals predominantly associated with the metal center (Figure c), , so the hole density of ions created by SFI may be expected to mimic these orbitals. An Fe + ion possesses an almost half empty d shell (4s 1 3d 6 ground state configuration), so from the point of view of the iron, excitation to a nonbonding molecular d hole is likely rather similar to excitation to an atomic half-occupied d orbital.…”

“…Valence UV–vis absorption spectroscopy, − coupled with ab initio calculations − and hard X-ray emission spectroscopy, has provided insight into the electronic structure of ferrocene. The frontier orbitals are nonbonding metal d orbitals, and the highest occupied bonding orbitals are formed from interactions of the remaining d orbitals with the π system of the aromatic rings.…”

Metastable Charged Dimers in Organometallic Species: A Look into Hydrogen Bonding between Metallocene Derivatives

“…Metallocenes , (MCp 2 , where M = metal atom and Cp = C 5 H 5 ), of which ferrocene (M = Fe) is the “parent” compound, have been intensely studied over the past 70 years, – not only experimentally but also from a computational perspective. , This work focuses on some metallocene derivatives with the potential to form hydrogen bonds, particularly via a carboxylic acid or amide group. These substituents are not only relevant from a crystal engineering perspective, as already mentioned, but they are important linking groups in other metallocene-containing macromolecules, particularly metallocene amino acid derivatives, for which understanding noncovalent interactions is key to understanding their structures and activity. – Specifically, we will study and characterize the structures, binding energies, and dissociation profiles of a series of closed-shell hydrogen-bonded dimers of the [(η 5 -C 5 H 5 )­M­(η 5 -C 5 H 4 –COX)] q (M = Fe, Ru, q = 0; M = Co, Rh, q = +1; M = Mn, q = −1; X = OH, NH 2 ) metallocene derivatives in the gas phase.…”