Unique Dispersion-Induced Tetrel Bond with Co-operative σ-hole-Induced Pnicogen Bond in the POCl 3 -Acetone Heterodimer: Experimental Confirmation at Low Temperatures.

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.