Photoelectron spectra of metallocenes

Cauletti, C.; Green, Jennifer C.; Kelly, Michaël G.; Powell, P.; Tilborg, Jane van; Robbins, John L.; Smart, James C.

doi:10.1016/0368-2048(80)80058-2

Cited by 178 publications

(145 citation statements)

References 29 publications

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“…The only other manganocene whose electronic structure has been studied extensively is (Me 5 C 5 ) 2 Mn. [15][16][17] The magnetic moment in the solid state (5-100 K) shows it to be lowspin and its EPR spectrum in frozen glasses and solid solutions of (Me 5 C 5 ) 2 Fe show that the ground state is 2 E 2g , consistent with the gas phase PES data. The room temperature solid-state X-ray crystal structure of (Me 5 C 5 ) 2 Mn with the Mn-C(ave) distances of 2.11 Å show it is low-spin but there are several distortions, which have been ascribed to a static Jahn-Teller distortion.…”

Section: Introductionsupporting

confidence: 77%

Supramolecular Catalysis of Orthoformate Hydrolysis in Basic Solution: An Enzyme-Like Mechanism

2008

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Abstract. Magnetic susceptibility measurements and X-ray data confirm that tert-butyl substituted manganocenes [(Me 3 C) n C 5 H 5-n ] 2 Mn (n= 1, 2) follow the trend previously observed with the methylated manganocenes, i.e., electron donating groups attached to the Cp ring stabilize the low-spin (LS) electronic ground state relative to Cp 2 Mn and exhibit higher spin-crossover (SCO) temperatures.However, introducing three CMe 3 groups on each ring gives a temperature invariant high-spin (HS) state manganocene. The origin of the high-spin state in [1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 Mn is due to the significant bulk of the [1,2,4-(Me 3 C) 3 C 5 H 2 ] -ligand, which is sufficient to generate severe inter-ring steric strain that prevents the realization of the low-spin state. Interestingly, the spin transition in [1,3-(Me 3 C) 2 C 5 H 3 ] 2 Mn is accompanied by a phase transition resulting in a significant irreversible hysteresis (∆T c = 16 K). This structural transition was also observed by extended X-ray absorption fine-structure (EXAFS) measurements. Magnetic susceptibility studies and X-ray diffraction data on SiMe 3 substituted 2 manganocenes [(Me 3 Si) n C 5 H 5-n ] 2 Mn (n= 1, 2, 3) show high-spin configuration in these cases. Although tetra-and hexasubstituted manganocenes are high-spin at all accessible temperatures, the disubstituted manganocenes exhibit a small low-spin admixture at low temperature. In this respect it behaves similarily to [(Me 3 C)(Me 3 Si)C 5 H 3 ] 2 Mn, which has a constant low-spin admixture up to 90 K and then gradually converts to high-spin. Thermal spin-trapping can be observed for [(Me 3 C)(Me 3 Si)C 5 H 3 ] 2 Mn on rapid cooling.

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Section: Introductionsupporting

confidence: 77%

Supramolecular Catalysis of Orthoformate Hydrolysis in Basic Solution: An Enzyme-Like Mechanism

2008

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“…1) at 9.0 ± 0.2 eV (peak B), 12.7 ± 0.2 eV (peak C), and 17.3 ± 0.2 eV (peak D) as well as the much weaker features at 0.9 ± 0.2 eV (peak A′) and 5.1 ± 0.2 eV (peak A″) are similar in relative intensities and binding energies to those assigned to cobaltocene adsorbed on cleaved graphite [32]. There is also a strong similarity between the gas phase photoemission spectra of cobaltocene [36][37], but with a shift of about 4 eV in the energy scale, as is typical of metallocenes [13][14][15], [17], [20][21][22][23], and [32], even though the moleculesubstrate as well as intermolecular interactions may shift, or broaden the molecular orbitals.…”

Section: Cobaltocene Adsorption On Cu(1 1 1)mentioning

confidence: 54%

“…Based on theoretical calculations of the ground-state molecular orbitals of cobaltocene [38], fi nal excited states [38] and gas-phase photoemission studies [36][37], we can assign these photoemission features of the adsorbed species and the induced photoemission features to the molecular orbitals of cobaltocene. With very large cobaltocene exposures (Fig.…”

Section: Cobaltocene Adsorption On Cu(1 1 1)mentioning

confidence: 99%

“…This results in formation of a surface species that somewhat resembles [Co(Cp) 2 ] + on graphite [32] but apparently leads to fragmentation on Cu (1 1 1). Ferrocene, with greater stability as an adsorbate, is a paired electron system in a singlet state, while nickelocene, which exists as a triplet state as an isolated molecule, almost certainly adopts a singlet state on adsorption due to lowered molecular symmetry [26] and [27] and possibly localization of an electron pair on a double bond arising from ring slippage of the carbocyclic ligand [36]. With absorption other than end-on, nickelocene MUST adopt a singlet state as the off normal adsorption orientation has reduced the molecular symmetry to such an extent that a triplet state is simply not possibly.…”

Section: The Stability Of Adsorbed Cobaltocenementioning

confidence: 99%

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Cobaltocene adsorption and dissociation on Cu(111)

Choi¹,

Dowben²

2006

Surface Science

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“…The PE spectrum of ferrocene 3 has been measured by various groups [13,17,18,49]. The first band at 6.86 eV corresponds to an ionization event out of the 4e2g combination, the second maximum at 7.23 eV is very sharp indicating the nonbonding nature of the MO from which the electron has been ejected.…”

Section: The Vertical Ionization Energies In the Outer Yalence Regionmentioning

confidence: 99%

The Electronic Structure of Closed Shell Metallocenes in the Ground State and in the Cationic Hole-States

Böhm

1982

Zeitschrift Für Naturforschung A

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The electronic structure of tne closed shell metallocenes bis(7r-cyclopentadienyl)magnesium (1), bisbenzene chromium (2), ferrocene (3) and cyclopentadienyl benzene manganese (4) has been studied in the ground state as well as in the low-lying cationic states. The computational framework is a semiempirical INDO Hamiltonian, the theoretical framework for the investigation of the cationic hole-states is the Green's function method. The calculated ionization energies are compared with the photoelectron (PE) spectra of the four closed shell metallocenes. The interrelation between theoretically determined reorganization energies and the localization properties of the orbital wave functions or the nature of the transition metal center is analyzed. General rules concerning the validity of Koopman's theorem in transition metal complexes are formulated.

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Photoelectron spectra of metallocenes

Cited by 178 publications

References 29 publications

Supramolecular Catalysis of Orthoformate Hydrolysis in Basic Solution: An Enzyme-Like Mechanism

Supramolecular Catalysis of Orthoformate Hydrolysis in Basic Solution: An Enzyme-Like Mechanism

Cobaltocene adsorption and dissociation on Cu(111)

The Electronic Structure of Closed Shell Metallocenes in the Ground State and in the Cationic Hole-States

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