INVESTIGATION OF DIHYDROGEN BONDED INTERACTION IN X3CH⋅⋅⋅HNA, X2CH2⋅⋅⋅HNA (X = F, CL, AND BR) BINARY AND TERNARY COMPLEXES: A DFT AND DFT-D3 APPROACH

Abstract

A theoretical study was conducted to investigate the dihydrogen and alkali-halogen bonding in binary X3CH⋅⋅⋅HNa, X2CH2⋅⋅⋅HNa and ternary complexes 2(X3CH)⋅⋅⋅HNa, 2(X2CH2)⋅⋅⋅HNa (where X = F, Cl, Br). The computations were performed using the B3LYP method with different basis sets, namely pople’s (6-311++G**) and dunning type (aug-cc-pVDZ and aug-cc-pVTZ). Additionally, dispersion-corrected density functional theory calculations were carried out for all the structures. The interpretation of structural parameters through interaction energy revealed that Br3CH⋅⋅⋅HNa complex has the shortest binding distance with more interaction energy. The results illustrate that the H⋅⋅⋅H interaction is strengthened in the ternary complexes compared to binary. The vibrational analysis divulged that C–H and H–Na stretching frequencies are blue and red shifted upon dihydrogen bond formation. Moreover, natural bond orbital (NBO), quantum theory of atoms in molecule (QTAIM), non-covalent interaction (NCI)–reduced density gradient (RDG) analysis were carried out to understand the nature of intermolecular interactions, followed by the molecular electrostatic potential (MEP) analysis which confirm the existence of non-covalent interaction between C‒H and H–Na bonds.