The Role of Non‐Covalent Interactions on Cluster Formation: Pentamer, Hexamers and Heptamer of Difluoromethane

Camilla Calabrese,Imanol Usabiaga,Berhane Temelso,Brooks H Pate,Emilio J Cocinero,Francisco J Basterretxea,Giacomo Prampolini,George C Shields,Luca Evangelisti,Nathan A Seifert

doi:10.1002/ange.202103900

Abstract

AbstractThe role of non‐covalent interactions (NCIs) has broadened with the inclusion of new types of interactions and aplethoraof weak donor/acceptor partners. This work illustrates the potential of chirped‐pulse Fourier transform microwave technique, which has revolutionized the field of rotational spectroscopy. In particular, it has been exploited to reveal the role of NCIs’ in the molecular self‐aggregation of difluoromethane where a pentamer, two hexamers and a heptamer were detected. The development of a new automated assignment program and a sophisticated computational screening protocol was essential for identifying the homoclusters in conditions of spectral congestion. The major role of dispersion forces leads to less directional interactions and more distorted structures than those found in polar clusters, although a detailed analysis demonstrates that the dominant interaction energy is the pairwise interaction. The tetramer cluster is identified as a structural unit in larger clusters, representing the maximum expression of bond between dimers.

Highlights

The role of non-covalent interactions (NCIs) has broadened with the inclusion of new types of interactions and a plethora of weak donor/acceptor partners
We have focused on the self-aggregation of a halocarbon which may be stabilized by a subtle balance of CÀH···F weak hydrogen bonds (WHBs), CÀF···F XBs or FÀC···F tetrel bonds, which were previously observed in (CH2F2)n···(H2O)m.[35]
Our interpretation of the geometric analysis discussed earlier agrees with these many-body decomposition (MBD) calculations since the tetramer scaffold is the ideal arrangement for optimizing interactions between pairs of dimers, which represent the most relevant energy component as shown by the MBD

Summary

Introduction

The role of non-covalent interactions (NCIs) has broadened with the inclusion of new types of interactions and a plethora of weak donor/acceptor partners. We present the generation and detection of several higher clusters of DFM (one pentamer, two hexamers and one heptamer).

Results

Conclusion