The effect of electron correlation on the metal—ligand bond in ferrocene

Lüthi, Hans Peter; Siegbahn, Per E. M.; Almlöf, Jan; Fægri, Knut; Heiberg, Anders

doi:10.1016/0009-2614(84)80427-3

Cited by 45 publications

(14 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In terms of absolute accuracy of the geometries, the errors in the Fe-S bond lengths are significant, but predictable, as is frequently the case with UHF calculations. 60,61 In terms of spin contamination, for every conformation, regardless of basis set, the actual S 2 values are very close to the ideal values of 8.75 and 6.00 for high spin Fe(III) and Fe(II), respectively. This signifies very little spin contamination in the UHF wave functions.…”

Section: Discussionmentioning

confidence: 66%

“…The energy difference between the oxidized and the reduced state, Δ E redox , for the rubredoxin like conformation, −2.13 eV, is lower than the −1.79 eV value reported by Mouesca et al and −1.67 eV from Goddard III et al The accuracy of this value remains to be proven. In terms of absolute accuracy of the geometries, the errors in the Fe−S bond lengths are significant, but predictable, as is frequently the case with UHF calculations. , …”

Section: Discussionmentioning

confidence: 97%

See 1 more Smart Citation

Conformational Dependence of the Electronic Properties of [Fe(SCH₃)₄]^-,2-

Koerner

Ichiye

1997

J. Phys. Chem. B

View full text Add to dashboard Cite

The electronic properties of [Fe(SCH 3 ) 4 ] -,2-, a model for the iron-sulfur site in rubredoxin, and the conformational dependence of these properties were investigated with ab initio calculations. The calculations were done at the unrestricted Hartree-Fock level with various basis sets, and the effects of electron correlation were tested in some calculations using second-order perturbation theory. The conformational dependence was studied using five conformations of the model complex that differed by rotations about the Fe-S and C-S bonds. Geometry optimizations showed that these bond lengths changed little among the conformations examined, except where steric crowding existed. The atomic spin populations and spin contamination values (S 2 ) were also homogeneous among the conformations. The relative energies of all but one of the conformations were very small in both the oxidized and reduced states; thus, the total energy changes upon reduction, ∆E redox , of all but one of the conformations were within 30 mV of each other. The exception was about 100 mV less negative than the other four structures and represents a less likely dihedral rotation transition state. More important, the difference of only 30 mV between conformations similar to that of the iron-sulfur site in rubredoxin and in the Holm-Ibers analogue indicates that very little of the 800 mV difference in redox potential between rubredoxin and in the Holm-Ibers analogue can be attributed strictly to conformationally dependent differences in electronic structure. In addition, atom-centered partial charges were determined by Mulliken's method and two different electrostatic potential (ESP) fitting methods: the surface-based geodesic tessellation method and the grid-based CHELPG method. For all three methods, the partial charge distributions showed little conformational dependence. Moreover, the Mulliken charges, which are not subject to the problems of buried atoms associated with ESP methods, indicate very little conformational dependence. The CHELPG partial charges were selected as being the most reasonable for ESP calculations; thus, a geometryindependent set of CHELPG partial charges is proposed.

show abstract

Section: Discussionmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 97%

Conformational Dependence of the Electronic Properties of [Fe(SCH₃)₄]^-,2-

Koerner

Ichiye

1997

J. Phys. Chem. B

View full text Add to dashboard Cite

show abstract

“…These energies are also consistent with previous calculations (26,37), where it was found that the location of a bent equilibrium geometry was basis set and method dependent. The use of reasonably sized all-electron basis sets in the calculations given here may be an important factor in obtaining a bent geometry for CaCp,, and indeed the large number of calculations for the group 2 dihalides (52, 53) and previous calculations of metallocenes (34)(35)(36) suggests that these systems are very sensitive to the basis sets and calculational methods chosen. Neverthe- less, our results support the contention that CaCp, is bent but very floppy.…”

Section: Geometriesmentioning

confidence: 96%

Topological studies of the charge density of some group 2 metallocenes M(η⁵-C₅H₅)₂ (M = Mg or Ca)

Bytheway¹,

Popelier²,

Gillespie³

1996

Can. J. Chem.

View full text Add to dashboard Cite

Ab initio quantum chemical calculations using both the Hartree-Fock and the B3LYP density functional theory methods have been performed for the group 2 metallocenes M(~~-c,H,), (M = Mg or Ca). The topology of the calculated charge density (p) and its Laplacian (vZp) have been analysed using a new critical point search algorithm in order to understand whyis linear while C~(~~-C , H , ) , is bent. The Laplacian of the core of the Ca atom in c~(~~-c , H , )~ is perturbed by the polarizing field of the cyclopentadienyl ligands and the bent geometry is a consequence of the interactions between the distorted core and the ligand atoms. In the case of M~ (~~-c , H , ) , , charge concentration maxima in the Mg core occur along the vectors connecting the metal to the centroids of the cyclopentadienyl ligands irrespective of whether or not the molecule is linear, and the preferred geometry is linear as expected. The results of these calculations demonstrate that the geometries of the group 2 metallocenes can be understood in terms of the repulsive interactions between the ligands and between the ligands and the distorted core of the metal atom.

show abstract

“…They improved the calculation by using the generalized-molecularorbital-configuration-interaction technique that reduced the error in the metal-ring distance to 0.070 A. Luthi et al [9] did an MCSCF-CI geometry optimization, with over a million configurations in the final CI, plus corrections for relativistic effects.…”

Section: Geometry Optimizations Of Other Complexesmentioning

confidence: 99%

Geometry optimization of organometallic complexes: A study of basis sets

Williamson

Hall

1987

Int. J. Quantum Chem.

View full text Add to dashboard Cite

Total geometry optimizations are reported for Cr(CO),, HMn(CO),, Fe(CO),, (C,H,)CT(CO)~. A variety of basis sets were examined, and, based on the results, a relatively compact and accurate basis set is proposed. The differences between the calculated and experimental metal-carbonyl, metal-benzene, and metal-nitrosyl bond distances average 0.03, 0.08, and 0.07 A, respectively. Calculated metal-cyclopentadienyl bond lengths were found to be an average of 0.15 8, longer than experimental bond lengths. Addition of electron correlation at the perfect pairing GVB level reduced the average difference in the metal-cyclopentadienyl bond length to 0.08 8,.Ni(CO)4, Cr(C6H6)29 Fe(C5H5),, Ni(C4H4)29 Cr(NO),, (CsHs)Mn(CO)3, and

show abstract

The effect of electron correlation on the metal—ligand bond in ferrocene

Cited by 45 publications

References 14 publications

Conformational Dependence of the Electronic Properties of [Fe(SCH₃)₄]^-,2-

Conformational Dependence of the Electronic Properties of [Fe(SCH₃)₄]^-,2-

Topological studies of the charge density of some group 2 metallocenes M(η⁵-C₅H₅)₂ (M = Mg or Ca)

Geometry optimization of organometallic complexes: A study of basis sets

Contact Info

Product

Resources

About

The effect of electron correlation on the metal—ligand bond in ferrocene

Cited by 45 publications

References 14 publications

Conformational Dependence of the Electronic Properties of [Fe(SCH3)4]-,2-

Conformational Dependence of the Electronic Properties of [Fe(SCH3)4]-,2-

Topological studies of the charge density of some group 2 metallocenes M(η5-C5H5)2 (M = Mg or Ca)

Geometry optimization of organometallic complexes: A study of basis sets

Contact Info

Product

Resources

About

Conformational Dependence of the Electronic Properties of [Fe(SCH₃)₄]^-,2-

Conformational Dependence of the Electronic Properties of [Fe(SCH₃)₄]^-,2-

Topological studies of the charge density of some group 2 metallocenes M(η⁵-C₅H₅)₂ (M = Mg or Ca)