Affiliation:
1. Department of Chemistry and Pharmaceutical Sciences AIMMS Vrije Universiteit Amsterdam De Boelelaan 1108 1081 HZ Amsterdam The Netherlands
2. Institute for Molecules and Materials Radboud University Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands
3. Department of Chemical Sciences University of Johannesburg Auckland Park Johannesburg 2006 South Africa
Abstract
AbstractWe have quantum chemically investigated the origin of the atypical blueshift of the H−C bond stretching frequency in the hydrogen‐bonded complex X−•••H3C−Y (X, Y=F, Cl, Br, I), as compared to the corresponding redshift occurring in Cl−•••H3N and Cl−•••H3C−H, using relativistic density functional theory (DFT) at ZORA‐BLYP‐D3(BJ)/QZ4P. Previously, this blueshift was attributed, among others, to the contraction of the H−C bonds as the H3C moiety becomes less pyramidal. Herein, we provide quantitative evidence that, instead, the blueshift arises from a direct and strong X−•••C interaction of the HOMO of A− with the backside lobe on carbon of the low‐lying C−Y antibonding σ* LUMO of the H3C−Y fragment. This X−•••C bond, in essence a tetrel bond, pushes the H atoms towards a shorter H−C distance and makes the H3C moiety more planar. The blueshift may, therefore, serve as a diagnostic for tetrel bonding.
Subject
Physical and Theoretical Chemistry,Atomic and Molecular Physics, and Optics