In all cases, the results were consistent with those for the 1 Â 1 Â 1 case (see Supplementary material, Tables S1 – S6) with very similar values of UME a, b, c and UME α, β, γ for each model at all computation sizes. Nevertheless, we repeated the calculations with 2 Â 1 Â 1, 1 Â 2 Â 1, 1 Â 1 Â 2, 2 Â 2 Â 1 and 2 Â 2 Â 2 unit cells. The size of the unit cell, having a minimum dimension larger than 8 Å, guarantees enough accuracy of the calculations accord- ing to the criteria given by Stewart. Regarding the percent error for the volume, it was 25.5% for Sparkle/AM1, 3.60% for Sparkle/PM3, 6.82% for Sparkle/PM6 and 2.01% for Sparkle/PM7.
With this model, the unsigned mean error (UME) in the calculations for a single unit cell is UME a, b, c 1⁄4 0.89% for the a, b and c parameters and UME α, β, γ 1⁄4 0.39% for the α, β and γ parameters. The comparison between the results obtained with the four models studied reveal that a substantial improvement in accuracy is obtained with the most recent Sparkle/PM7 model. In the Er – N distances are 2.523(5) and 2.568(5) Å, with a N – Er – N bite angle of 64.3 ° and the Er – O distances range from 2.287(4) to 2.324(4) Å (Fig. The coordination geometry of is very similar to that found in the related complex. Consequently, the Er – O bond lengths in are larger than that in. The Er-bath bonding is not purely electrostatic and its formation is accompanied by a decrease in the Er-acac bond energy. The comparison of Er – O bond lengths in with the corresponding bonds lengths in is directly related to the interactions of this mono ligand complex with the additional ligand, bathophenathroline, whose introduction in the coordination sphere of erbium stimulates redistribution of electronic density in the ternary complex. The bathophenanthroline molecules are not planar, as the terminal phenyl rings are rotated 61.36(15) ° and 70.29(17) ° with respect to the central phenanthroline unit. The slight distortion of the β -diketonate rings occurs along the axis connecting the two oxygen atoms of the ligand. The chelating ring associated with bathophenanthroline also possesses nearly planar geometry. The six-membered chelate rings formed by Er 3 þ and the acetylacetonate ligands possess nearly planar geometries. Selected geometric parameters are given in Table 2. The angle between the least-squares planes of the square faces is just 2 °. The trivalent erbium ion lies approximately in the middle of the anti- prism with a distance of 1.39 Å to the face containing the N atoms and 1.19 Å to the opposite face containing exclusively oxygens. The lanthanide ion is eight-coordinated by six O atoms from the acetylacetonate anions and two N atoms from the bathophenanthroline molecule, forming a distorted square-antiprismatic structure in which the set N1, N2, O3, O4 and the set O1, O2, O5, O6 form two approximate squares, respectively (Fig. was not long enough to get sharp peaks from the Fourier transform of the dipole moment, we also used compressed sensing in the analysis of the propagation.
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