Can the BB multiple bonds be as the stronger hydrogen-bond proton acceptors than the CC multiple bonds: A comparative theoretical investigation on unusual intermolecular T-shaped XH…π interaction between HF and HBBH (3Σg-), HBBH (1Δg), OCBBCO, H2CCH2

The unusual T-shaped XH…π hydrogen bonds between HF and BB or CC multiple bonds are compared using the (U)MP2 and DFT ((U)B3LYP functional) methods with the 6-311++G(2df,2p) and aug-cc-pVTZ basis sets. The binding energies follow the order of HBBH (1Δg)…HF > H2CCH2…HF > HCCH…HF > OCBBCO…HF > HBBH (3Σg-)…HF. NBO analysis and the results of the AIM charge density and electron density shifts confirm that, although BB multiple bonds are more electron-deficient than CC multiple bonds, HBBH (1Δg) can be as the stronger T-shaped XH…π hydrogen-bond proton acceptor than the CC multiple-bond monomers.