Journal ArticleDOI
Molecular Structure of Dicyclopentadienylnickel (C5H5)2Ni
Lise Hedberg,Kenneth Hedberg +1 more
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The structure of the gaseous nickelocene has been determined at 110°C by electron diffraction using two independent sets of data as mentioned in this paper, which leads to the conclusion that the rings are rotating much more freely than in ferrocene.Abstract:
The structure of gaseous nickelocene has been determined at 110°C by electron diffraction using two independent sets of data. The molecule has the familiar ferrocenelike sandwich shape, but it differs from ferrocene in having weaker metal–carbon bonds and greater amplitudes of vibration for all distances affected by motion of the cyclopentadienyl rings as units. The simplest interpretation of the large inter‐ring amplitudes leads to the conclusion that the rings are rotating much more freely than in ferrocene. There is some slight evidence that the Ni–C bonds may not all be equivalent, corresponding to a structure that is not strictly symmetric (D2h or D2d), or alternatively that the molecular motions affecting the Ni–C bonds are unusual in a way which does not give rise to the expected essentially harmonic Ni–C amplitudes, either of which suggests the faint possibility of a Jahn–Teller effect. Based upon a symmetric sandwich conformation with freely rotating rings the principal distance (ra) and mean amplitude (la) values are (values in parentheses are 2σ): rNi–C = 2.196 A (0.008), rC–C = 1.430 A (0.003), rC–H = 1.083 A (0.019), ∠C5,H (angle between the plane of the C5 ring and the C–H bond) = 0.28° (2.90), lNi–C = 0.0842 A (0.0056), lC–C = 0.0440 A (0.0031), lC–H = 0.0786 A (0.0229), lNi···H = 0.1469 A (0.0346).read more
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Structural criteria for the mode of bonding of organoactinides and -lanthanides and related compounds
TL;DR: In this paper, the authors summarized much of the structural information accumulated during the last ten years, focusing on the unifying structural trends in these compounds and the question of the mode of bonding.
Journal ArticleDOI
Systematic Investigation of Electronic and Molecular Structures for the First Transition Metal Series Metallocenes M(C5H5)2 (M = V, Cr, Mn, Fe, Co, and Ni)
TL;DR: In this article, the electronic structures of the first-row transition metal metallocenes, MCp2 (M = V, Cr, Mn, Fe, Co, and Ni), have been studied using a broad range of density functional methods with flexible double-ζ plus polarization (DZP) basis sets.
Journal ArticleDOI
Atomic Motions in Molecular Crystals from Diffraction Measurements
TL;DR: The information provided by modern crystal structure analyses is not limited to the atomic arrangement, but also includes, for each atom, a set of quantities known as anisotropic Gaussian displacement parameters (ADP's), which provide information about averaged displacements of atoms from their mean positions as discussed by the authors.
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Density functional calculations of NMR shielding tensors for paramagnetic systems with arbitrary spin multiplicity: validation on 3d metallocenes.
Peter Hrobárik,Roman Reviakine,Alexei V. Arbuznikov,Olga L. Malkina,Vladimir G. Malkin,Frank H. Köhler,Martin Kaupp +6 more
TL;DR: The calculation of nuclear shieldings for paramagnetic molecules has been implemented in the ReSpect program, which allows the use of modern density functional methods with accurate treatments of spin-orbit effects for all relevant terms up to order Omicron(alpha4) in the fine structure constant.
References
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Journal ArticleDOI
A New Type of Organo-Iron Compound
T. J. Kealy,P. L. Pauson +1 more
TL;DR: In this article, the reaction of Grignard reagents with anhydrous ferric chloride was studied, but no definite evidence for organo-iron compounds was found in such reactions.
Journal ArticleDOI
The crystal structure of ferrocene
TL;DR: A detailed X-ray analysis of crystals of ferrocene by Dunitz, Orgel & Rich as mentioned in this paper confirmed that the molecule has a "sandwich" structure with approximate D5d symmetry, and Fe-C, 2.045±0.02 A.
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The vibrational spectra and structure of ferrocene and ruthenocene
TL;DR: In this article, the infrared and Raman spectra of ferrocene, ruthenocene and cyclopentadienyl rings have been reported and a detailed assignment of frequencies to the fundamental modes of vibration has been made for these compounds.