Electronically tuned molecular torsion balances via remote substituents: a stabilizing factor for S ? O chalcogen bond

Noncovalent interactions have an impact on the properties of condensed phases, solutions, and crystals. These interactions can occur between groups within a molecule (intra-) or between molecules (inter-). The current report examines a series of molecular balances as a quantitative method for evaluating the electronic effects of electron-donating (ED) and electron-withdrawing (EW) substituents in the para-position. Additionally, the impact on the stabilization of the two isomers (open and closed) and the strength of the intramolecular interactions is discussed in the report. The relative stability of the geo-metrical isomers, as well as the enthalpy, Gibbs free energy, and entropy for all 24 structures are analyzed. It was noted that the stability of the structures was associated with the substituents and the nature of the conformer. A strong positive correlation was observed between the calculated relative enthalpies and total energies as with R-2 = 0.96. The calculated ?H ranges between - 13.77 and 5.74 kJ mol(-1) , substitution of ED resulted in ?H < 0, and the most negative value observed for strong ED namely N(CH3)(2). It is worth noting that substitution of EW resulted in positive values of ?H except for F. The calculated highest occupied molecular orbital and lowest unoccupied molecular orbital are found in the ranges - 5.19 to - 6.78 eV and - 5.58 to - 6.16 eV for open and closed conformers, respectively. The preference for the folded state can be attributed to weak S ? O chalcogen interactions. The observed relationship between electronic effects and torsional and chalcogen bonding properties offers insights into designing and manipulating molecular systems with specific conformational preferences and noncovalent interactions that may have potential implications in the development of molecular switches, sensors, and materials with tailored properties.