The Characteristics of Disulfide-Centered Hydrogen Bonds.

The disulfide-centered hydrogen bonds in the three different model systems of diethyl disulfide⋅⋅⋅H O/H CO/HCONH clusters were characterized by high-resolution Fourier transform microwave spectroscopy and quantum chemical computations. The global minimum energy structures for each cluster are experimentally observed and are characterized by one of the three different S-S⋅⋅⋅H-C/N/O disulfide-centered hydrogen bonds and two O⋅⋅⋅H-C hydrogen bonds. Non-covalent interaction and natural bond orbital analyses further confirm the experimental observations. The symmetry-adapted perturbation theory (SAPT) analysis reveals that electrostatic is dominant in diethyl disulfide⋅⋅⋅H O/HCONH clusters being consistent with normal hydrogen bonds, whilst dispersion takes over in diethyl disulfide⋅⋅⋅H CO cluster. Our study gives accurate structural parameters for the disulfide bond involved non-covalent clusters providing important benchmarking data for the theoretical evaluation of more complex systems.