Characterization of competing halogen-bonding and hydrogen-bonding motifs in the acetonitrile/hydrogen iodide dimer

Systematic analysis of electronic barrier heights and widths for concerted proton transfer in cyclic hydrogen bonded clusters: (HF)n, (HCl)n and (H2O)n where n = 3, 4, 5

“…Although correlation consistent basis sets with an additional set of tight d-functions (aug-cc-pV( X +d)Z) are available for Cl, 139 we found that replacing the ha X Z and a X Z basis sets with their ha( X +d)Z and a( X +d)Z counterparts changed the CBS values reported for (HCl) 3 and (HCl) 4 in Table 5 by no more than 0.01 kcal mol −1 , while the corresponding ranges changed by no more than ±0.01 kcal mol −1 for the trimer and ±0.03 kcal mol −1 for the tetramer. These observations are consistent with our previous findings regarding the negligible impact of tight d-functions on non-covalent dimers containing HCl or H 2 S. 113,140–143 The Δ E values obtained from each level of theory and from the extrapolations can be found in Tables S37–S45 of the ESI †…”

SMALL NON-COVALENT DIMERS WITH COMPETING HYDROGEN BONDED & HALOGEN BONDED MOTIFS

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The MP2 and CCSD(T) methods have been used in conjunction with large correlation consistent basis sets to characterize simple dimers in which halogen-bonded configurations can be energetically competitive with the hydrogen-bonded structures [1,2]. In the case of dimers formed between HCN and a diatomic hydrogen halide molecule (HX where X = Cl, Br or I), the linear halogen-bonded arrangement (HCN• • • XH) is a local minimum with an electronic energy that gets closer to that of the corresponding linear hydrogen-bonded global minimum (HCN•••HX) as the size of the halogen atom increases.

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