On the Accuracy of Theoretically and Experimentally Determined Electron Densities of Polar Bonds

Abstract

In the present study, we employ a set of different sulfur−nitrogen compounds, which contains eight different SN bonds of varying polarity, to study descrepancies between experimentally and theoretically derived electron densities characterized by their topological properties at the bond critical point according to Bader's quantum theory of atoms in molecules approach. First, the convergency of the computationally obtained parameters with respect to the theoretical approach (flexibility of the basis sets, method of computation, influence of substituents) is presented. A comparison with the experiment is performed by a direct comparison of the theoretical and experimental counterparts and by an investigation into what extent the various data sets exhibit relationships to the nature of the bonds. This approach allows testing of the self-consistency of the theoretical and experimental data, respectively. Finally, the outcomes of the atoms-in-molecules approach is compared with results obtained from the natural bond orbital approach and natural resonance theory.

Electron density of a new EGFR Tyrokinase-inhibitor at 100 K, consideration of different models

“…. These results support the usual findings that for heteroaromatic bonds the difference between experiment and theory is larger than, for example, for C-C bonds [25]- [27] cussed to be around 0.1 eÅ -3 and 2.5 eÅ -5 , respectively, [28] the agreement between the experimental and theoretical bond topological properties in the present study is reasonable. …”

“…This means that the main effect is not an increase of the Bader-basins but an increase of V 001 inside these basins. This effect is not seen for H(11), which may be attributed to the close appearance of the oxygen atom O (27) dium range HB. The low value of V 001 (H (11)) is due to the connection to a nitrogen atom, which is more electronegative than carbon, and the participation in the N(11)-H(11)···O (27) ) the electronegativity of carbon atoms increases, too.…”

“…This was not found to be true. Instead (IIa) builds a dimer in the crystal, two molecules are connected via a center of symmetry through the intermolecular hydrogen bond N(11)-H(11)···O (27) …”

“…To overcome the shortcomings of the standard model [25]- [27] one can refine individual κ' for each spherical harmonic against the theoretical structure factors [39] of model compound (III), which leads to a better description of the bond. Additionally one can examine different n l sets (l = 1-4) for the radial functions of the spherical harmonics.…”

Elektronendichteverteilung in einem Metallaphosphan

“…Dieser Effekt ist wohlbekannt für kombinierte experimentelle und theoretische Untersuchungen. [22] Der Laplace-Operator am BCP der P-C-Bindung ist nach der Berechnung leicht positiv (5 2 1 = + 1.30/ + 1.28 e À5 ) und nach dem Experiment negativ (5 2 1 = À4.83/À6.25 e À5 ). Die Konturliniendarstellungen dagegen ähneln einander und sind auch den zwei PPh-Einfachbindungen in [(Et 2 O)Li{Ph 2 P(CHPy)(NSiMe 3 )}] ähnlich.…”