A comparative study of S···π chalcogen bonds between SF2 or SFH and C C multiple bonds

Abstract We theoretically study chalcogen bonds involving SF 2 and SFH, each paired with various unsaturated hydrocarbons ethyne, ethene, 1,3-butadiene, and benzene. The binding energies are calculated at theory level MP2, M06-2X-D3 and CCSD(T)/CBS, respectively. Geometry structure, binding energies, interaction type and strength are studied comparatively. SFH engages in a stronger chalcogen bond than does SF 2 for all systems, which indicates that SFH is a stronger electron acceptor than SF 2 . Two kinds of energetic effects are observed, SF 2 ···cis-butadiene complex contain the strongest chalcogen bond among all the SF 2 ···π complexes, which is attributed to the energetic effect of two S···π interactions. For SFH···π complexes, the strongest interaction is formed between SFH and C 6 H 6 , which can be explained by the synergistic effects of the S···π and S H···π interaction. The largest charge transfer arises from the occupied C C bonding orbital to the σ*(S F) antibonding orbital. The quantity is considerably larger for SFH than for SF 2 .