Interplay of Tetrel, Hydrogen, and Halogen Bonds in FGeOCl and HCN Complexes: A Comprehensive Theoretical Study of Dimers, Trimers, and Tetramers.

This study investigates the nature and interplay of noncovalent interactions (NCIs)─tetrel bonds (TB), hydrogen bonds (HB), and halogen bonds (XB)─in molecular assemblies formed between trifluorogermyl hypochlorite (FGeOCl) and hydrogen cyanide (HCN). Using a combination of high-level computational methods, we explored the geometric, energetic, and electronic properties of dimers, trimers, and tetramers formed in different molar ratios of interacting reagents. Various analyses reveal a significant cooperativity between TB and HB, which mutually reinforce each other, while XB interactions are diminished in the presence of TB and HB. Energy decomposition analysis (EDA) through SAPT and sobEDAw methods identified electrostatic and orbital interactions as key contributors to the stabilization of TB and HB, while dispersion plays a prominent role in XB. A perfect linear correlation was found between interaction energy and charge density at bond critical points (BCPs), underscoring the predictive value of these metrics. These findings shed light on the cooperative nature of NCIs and provide a framework for designing molecular systems in supramolecular chemistry and crystal engineering.