Слабкий водневий зв’язок у комплексах CD3Hal···HCl: ІЧ спектроскопія та розрахунки методом MP2

• Date: 2026
• Main Authors: Murodov, G., Doroshenko, I., Hushvaktov, H., Khujamov, U., Nurmurodova, G.
• Format: Article
• Language: English; Ukrainian
• Published: Publishing house "Academperiodika" 2026
• Subjects: дейтерованi метилгалогенiди; водневий зв’язок; iнфрачервона спектроскопiя; рiдкий аргон; розрахунки методом MP2; спектральнi зсуви; слабкi мiжмолекулярнi взаємодiї
• Online Access: https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2023829
• Journal Title: Ukrainian Journal of Physics

The formation and vibrational properties of CD3Hal ··· HCl complexes (Hal = F, Cl, Br) were investigated in liquid argon at 120 K using infrared (IR) spectroscopy and anharmonic frequency calculations at the MP2/6-311++G(3df,3pd) level. Upon complex formation, the ν (HCl) stretching band exhibited systematic red shifts, increasing from CD3F to CD3Br, accompanied by band narrowing due to reduced rotational freedom of the bound HCl. For the CD3F ··· HCl complex, additional red shifts of 16 and 12 cm−1 were observed in the ν (CF) and νβ (CD3) modes, respectively, in agreement with the computed results. Charge distribution analysis revealed geometry changes consistent with non-linear complex structures. Force constants and reduced masses were calculated to rationalize spectral intensity variations. Atoms in Molecules (AIM) topological analysis confirmed weak hydrogen bonds with energies ranging from 2.6 to 5.5 kcal · mol−1, correlating with the halogen electronegativity (F > Cl > Br). The agreement between experimental and theoretical data highlights the relationship between vibrational shifts, bond strength, and electronic structure in weakly hydrogen-bonded systems.