Fundamental Relation between Molecular Geometry and Real-Space Topology. Combined AIM, ELI-D, and ASF Analysis of Hapticities and Intramolecular Hydrogen鈥揌ydrogen Bonds in Zincocene-Related Compounds
文摘
Despite numerous advanced and widely distributed bonding theories such as MO, VB, NBO, AIM, and ELF/ELI-D, complex modes of bonding such as M鈥揅p*(R) interactions (hapticities) in asymmetrical metallocenes or weak intramolecular interactions (e.g., hydrogen鈥揾ydrogen (H路路路H) bonds) still remain a challenge for these theories in terms of defining whether or not an atom鈥揳tom interaction line (a 鈥渃hemical bond鈥? should be drawn. In this work the intramolecular Zn鈥揅Cp*(R) (R = Me, 鈭?CH2)2NMe2, and 鈭?CH2)3NMe2) and H路路路H connectivity of a systematic set of 12 zincocene-related compounds is analyzed in terms of AIM and ELI-D topology combined with the recently introduced aspherical stockholder fragment (ASF) surfaces. This computational analysis unravels a distinct dependency of the AIM and ELI-D topology against the molecular geometry for both types of interactions, which confirms and extends earlier findings on smaller sets of compounds. According to these results the complete real-space topology including strong, medium, and weak interactions of very large compounds such as proteins may be reliably predicted by sole inspection of accurately determined molecular geometries, which would on the one hand afford new applications (e.g., accurate estimation of numbers, types, and strengths of intra- and intermolecular interactions) and on the other hand have deep implications on the significance of the method.