This study aims to investigate the electronic and structural properties of complexes formed between phenol (PhOH) and PH₂X derivatives using quantum chemical calculations at the MP2/6-311 + + G(2d,2p) level of theory. Molecular electrostatic potential (MEP) analysis revealed that phenol can act as both an electron donor and an electron acceptor through its hydroxyl functional group, whereas PH₂X derivatives function as electron acceptors via the σ-holes located on the halogen and phosphorus atoms. Geometry optimization led to the identification of three relaxed cyclic structures resulting from these interactions. Structure A is primarily stabilized by hydrogen–hydrogen (HB–HB) interactions, structure B by cooperative hydrogen–halogen (HB–XB) bonding, and structure C predominantly by pnictogen–hydrogen (PnB–HB) interactions. The relative stability of the complexes follows the order B < A< C. Further analyses using Natural Bond Orbital (NBO) and Atoms-in-Molecules (AIM) methods confirmed that although two interactions coexist simultaneously in all structures, the PnB and XB interactions exert the most significant influence on the stability of complexes C and A, respectively.
