Structural Evidence for the Expected Jahn-Teller Distortion in Monoanionic C60: Synthesis and X-ray Crystal Structure of Decamethylnickelocenium Buckminsterfulleride

1995 ◽  
Vol 117 (37) ◽  
pp. 9580-9581 ◽  
Author(s):  
Wai Chou Wan ◽  
Xioahua Liu ◽  
Gregory M. Sweeney ◽  
William E. Broderick
2015 ◽  
Vol 71 (11) ◽  
pp. 936-943 ◽  
Author(s):  
Arumugam Thangavel ◽  
Marika Wieliczko ◽  
Christopher Scarborough ◽  
Birger Dittrich ◽  
John Bacsa

In the crystal structure of the title homoleptic CrIIcomplex, [Cr(CH3CN)6](C24H20B)2·CH3CN, the [Cr(CH3CN)6]2+cation is a high-spind4complex with strong static, rather than dynamic, Jahn–Teller distortion. The electron density of the cation was determined by single-crystal X-ray refinements using aspherical structure factors from wavefunction calculations. The detailed picture of the electronic density allowed us to assess the extent and directionality of the Jahn–Teller distortion of the CrIIcation away from idealized octahedral symmetry. The topological analysis of the asphericald-electron density about the CrIIcation showed that there are significant valence charge concentrations along the axial Cr—N axes. Likewise, there were significant valence charge depletions about the CrIIcation along the equatorial Cr—N bonds. These charge concentrations are in accordance with a Jahn–Teller-distorted six-coordinate complex.


1991 ◽  
Vol 44 (10) ◽  
pp. 1495 ◽  
Author(s):  
RC Bott ◽  
DS Sagatys ◽  
DE Lynch ◽  
G Smith ◽  
CHL Kennard ◽  
...  

The copper(II) complex with citric acid (NH4)4 [Cu(C6H5O7)2] has been prepared, and its structure determined by X-ray diffraction, giving a residual R 0.035 for 1208 observed reflections. Crystals are monoclinic, space group P21/c with Z 2 in a cell of dimensions a 8.755(3), b 13.185(4), c 9.364(2)Ǻ, β 113.73(2)°. The complex is a centrosymmetric six-coordinate monomer which is isomorphous with ammonium zinc(II) citrate. However, the Cu-O(hydroxyl) bonds [2.341(3)Ǻ] show Jahn-Teller distortion relative to the Cu-O(carboxyl) bonds [1.969(3) and 1.977(3)Ǻ].


2020 ◽  
Author(s):  
Marta L. Vidal ◽  
Michael Epshtein ◽  
Valeriu Scutelnic ◽  
Zheyue Yang ◽  
Tian Xue ◽  
...  

We report a theoretical investigation and elucidation of the x-ray absorption spectra of neutral benzene and of the benzene cation. The generation of the cation by multiphoton ultraviolet (UV) ionization as well as the measurement of<br>the carbon K-edge spectra of both species using a table-top high-harmonic generation (HHG) source are described in the companion experimental paper [M. Epshtein et al., J. Phys.<br>Chem. A., submitted. Available on ChemRxiv]. We show that the 1sC -> pi transition serves as a sensitive signature of the transient cation formation, as it occurs outside of the spectral window of the parent neutral species. Moreover, the presence<br>of the unpaired (spectator) electron in the pi-subshell of the cation and the high symmetry of the system result in significant differences relative to neutral benzene in the spectral features associated with the 1sC ->pi* transitions. High-level calculations using equation-of-motion coupled-cluster theory provide the interpretation of the experimental spectra and insight into the electronic structure of benzene and its cation.<br>The prominent split structure of the 1sC -> pi* band of the cation is attributed to the interplay between the coupling of the core -> pi* excitation with the unpaired electron<br>in the pi-subshell and the Jahn-Teller distortion. The calculations attribute most of<br>the splitting (~1-1.2 eV) to the spin coupling, which is visible already at the Franck-Condon structure, and estimate the additional splitting due to structural relaxation to<br>be around ~0.1-0.2 eV. These results suggest that x-ray absorption with increased resolution might be able to disentangle electronic and structural aspects of the Jahn-Teller<br>effect in benzene cation.<br>


2020 ◽  
Vol 76 (11) ◽  
pp. 1720-1724
Author(s):  
Abigail J. Hall ◽  
Matthias Zeller ◽  
Curtis M. Zaleski

The synthesis and crystal structure of the title compound [systematic name: di-μ-acetato-tetrakis(μ4-N,2-dioxidobenzene-1-carboximidato)hexamethanoltetramanganese(III)nickel(II) methanol disolvate monohydrate], [Mn4Ni(C7H4NO3)4(C2H3O2)2(CH4O)6]·2CH4O·H2O or Ni(OAc)2[12-MCMn(III)N(shi)-4](CH3OH)6·2CH3OH·H2O, where MC is metallacrown, −OAc is acetate, and shi3− is salicylhydroximate, are reported. The macrocyclic metallacrown is positioned on an inversion center located on the NiII ion that resides in the central MC cavity. The macrocycle consists of an MnIII–N–O repeat unit that recurs four times to generate an overall square-shaped molecule. Both the NiII and MnIII ions are six-coordinate with an octahedral geometry. In addition, the MnIII ions possess an elongated Jahn–Teller distortion along the z-axis of the coordination environment. The interstitial water molecule is slightly offset from and disordered about an inversion center.


1989 ◽  
Vol 44 (7) ◽  
pp. 715-720 ◽  
Author(s):  
Dietrich Babel ◽  
Michael Otto

The crystal structures of the isotypic monoclinic fluorides Na2CuF4 (a = 326.7(1), b = 937.0(2), c = 561.2(1) pm, β = 92.49(1)°; V = 171.63 x10-30 m3) and Na2CrF4 (a = 334.8(1), b = 954.9(2), c = 566.5(3) pm, β = 92.85(3)°; V = 180.89 × 10-30 m3) have been redetermined by single crystal X-ray methods. The compounds are Jahn-Teller distorted variants of the orthorhombic Sr2PbO4type (space group Pbam) and crystallize with Z = 2 in space group P21/c, a subgroup of Pbam. They form a chain structure of edge-sharing octahedra which are strongly elongated. The following distances were obtained: Cu-F = 190.4/193.8/235,7(2) pm and Cr-F = 199.1/199.7/241.7(4) pm. The geometry is compared to that of the corresponding distorted rutile type difluorides; relations to further compounds are discussed.


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