Theoretical Study on Dihydrogen Bond Interaction Dominated Dodecaborate-Solvent Molecular Clusters

Dihydrogen bonds (DHB, X—H *δ* + …H *δ* —Y) have attracted significant attention due to their remarkable applications in molecular recognition, catalytic dehydrogenation, and drug design, *etc* . Although conventional hydrogen bonds (HBs) have been extensively and deeply studied, systematic research on these uncommon DHBs remains limited. Using high-level quantum chemical calculations and a dodecaborate-solvent molecular cluster model, this work systematically investigates the DHB interactions between dodecaborate anion ( B₁₂ H₁₂²⁻ ) and ten different selected solvent molecules, including CH 3 COOH, CH 3 NO 2 , CH 3 CN, CH 3 CHO, H 2 O, CH 3 OH, CH 3 NH 2 , CH 3 F, CH 3 CH 3 , and CH 4 . The results indicate that all solvent molecules (except CH 3 F) form significant DHBs with B₁₂ H₁₂²⁻ anion. Among them, CH 3 COOH exhibits the strongest binding energy (28.09 kcal•mol⁻ 1 ), while CH 4 shows the weakest (3.58 kcal•mol⁻ 1 ). Energy decomposition analysis (EDA) reveals that the contribution of electrostatic interactions in polar solvents significantly exceeds that in non-polar solvents, resulting in substantially higher binding energies for polar solvents. However, the dispersion and induction interactions play a dominant role in non-polar solvents. Further quantum theory of atoms in molecules (QTAIM) topological analysis shows that the electron density ( *ρ* ), Laplacian (∇² *ρ* ), and kinetic energy density ( *G* ) at bond critical points (BCPs) agree well with the trend of binding energy, providing effective indicators for predicting the strength of DHB. Additionally, spectral simulation based on density of states (DOS) distribution reveals that different solvent molecules can effectively regulate the specific molecular orbitals of B₁₂ H₁₂²⁻ anion, thereby affecting its photoionization properties. This study comprehensively explores the interaction strength and quantum fundamental characteristics of boron-based DHBs, providing theoretical support for the expansion of applications dominated by DHB interactions in the future.