Matrix Isolation IR Spectroscopic Investigation of S-H···S-S H-Bond in H₂S-Diethyl Disulfide Complex

S-H···S-S H-bonded 1:1 diethyl disulfide (DEDS)-H₂S complexes have been investigated by using FTIR spectroscopy in cold, solid argon (Ar) and nitrogen (N₂) matrices. H₂S was found to form one or two S-H···S-S H-bonds with the DEDS molecule, while H₂O is known to form only a single O-H···S-S H-bond. A total of five distinct H-bonded complexes have been identified for the two lowest energy rotamers of DEDS: three with the most stable GGG conformer and two with GGG'. Their binding energies varied from 2.43 to 3.05 kcal mol^-1. All five binary complexes were observed in the N₂ matrix, while only three complexes of GGG conformer could be identified in the Ar matrix as relative energy of GGG' is known to increase significantly in the presence of Ar. Activation barriers for interconversion of the five binary complexes were calculated and were found to vary from 0.08 to 2.65 kcal mol^-1. S-S linkage in DEDS has been found to be a more efficient acceptor for S-H H-bond donor than the S atom in H₂S. Dispersion interaction plays a major role toward overall stabilization of the H-bonded complexes and was found to be on the higher side among all sulfur-centered H-bonds studied until now.