Unusual Changes of C−H Bond Lengths in Chiral Zinc Complexes Induced by Noncovalent Interactions

Abstract

In order to better understand the effect of non-covalent weak interactions on molecules, we have explored a variety of weak interactions, such as improper H-bonding (HB), tetrel bonds (TBs) and halogen bonds, in fluorinated chiral zinc complexes. High resolution neutron diffraction studies revealed a methylene carbon-hydrogen bond elongation and shortening due to TB and improper HB interactions, respectively. To show the accumulative effects of multiple weak interactions on the CÀ H bond, three types of tetrel bonds have been carefully examined. We have also shown how CÀ H bond elongation can be easily offset by forming an improper HB with the H atom from this CÀ H bond. Non-covalent interaction and electrostatic potential analysis investigations have been used to affirm the nature of the interactions based on density functional theory (DFT) and other related calculations.

Locating Interstitial Hydrides in MH2@Cu14 (M = Cu, Ag) Clusters by Single-Crystal X-ray Diffraction

“…As XRD has matured and developed, it has become possible to determine the positions of hydrogen atoms by analyzing the electron density map. However, accurately determining the position of hydrogen atoms and the length of C–H bonds in a molecule using XRD methods can be challenging, as these methods are known to underestimate the C–H bond lengths . To supplement XRD analysis, computational methods such as Hirshfeld atomic refinement (HAR) have been developed, enabling anisotropic refinements for hydrogen atoms, although the accuracy is somewhat lower compared to atomic displacement parameters (ADPs) obtained from neutron diffraction. , It is important to consider the quality of the diffraction data, as insufficient data may limit the refinement to isotropic parameters.…”