Unique Dispersion-Induced Tetrel Bond with Co-operative σ-hole-Induced Pnicogen Bond in the POCl₃-Acetone Heterodimer: Experimental Confirmation at Low Temperatures

Abstract

Both tetrel and pnicogen bonds are known to be induced through σ-/π-holes. This work reports computational and experimental evidence of the carbonyl carbon of acetone hosting a tetrel bond by dispersion rather electrostatic forces, for the first time, while phosphorus of POCl 3 sustains pnicogen bonding via the σ-hole. Heterodimers of POCl 3 with acetone (CH 3 COCH 3 ) have been isolated within inert gas matrixes of Ar and N 2 at 12 K. Characteristic vibrational bands at P�O stretching of POCl 3 and C�O stretching of CH 3 COCH 3 have been obtained in support of the computations. The potential energy surface has been traced computationally using ab initio and density functional methods. CH 3 COCH 3 harboring such a tetrel bond, in itself, is quite intriguing. The interplay of these interactions has been comprehended by the quantum theory of atoms in molecules, natural bond orbital, energy decomposition, electrostatic potential mapping, and noncovalent interaction analyses.

π‐hole driven N⋅⋅⋅O/N⋅⋅⋅π Pnicogen and C⋅⋅⋅O Tetrel Bonding inNitromethane‐Carbonyl Dimers: Comprehensive Study using Matrix Isolation Infrared Spectroscopy and Quantum Chemical Computations

“…On matrix isolation of acetone (ACN), absorptions at 1721.5 cm À 1 and 1723.8 cm À 1 are observed within Ar and N 2 matrixes, respectively, which are attributed to the ν 3 mode(C=O stretching) of acetone (Figure 7). [31,76] In Ar matrix, a new absorption at 1717.5 cm À 1 occurs upon addition of NM whose intensity increases with the corresponding increment in NM concentration. A new absorption was observed within N 2 matrix at 1721.3 and 1719.5 cm À 1 .…”