Selective Trapping of Labile S-3 in a Porous Coordination Network and the Direct X-ray Observation

Abstract

S-3 is one of the basic allotropes of sulfur but is still a mysterious labile species. We selectively trapped S-3 in a pore of a thermally stable coordination network and determined S-3 structure by ab initio X-ray powder diffraction analysis. S-3 in a pore has a C-2, bent structure. The network containing trapped S-3 is remarkably stable under ambient conditions and is inert to photoirradiation. S-3 in the network could be transformed to S-6 by mechanical grinding or heating in the presence of NH4X (X = Cl or Br). S-6 could be reverse-transformed to S-3 by photoirradiation. We also determined the structure of the network containing S-6 by ab initio X-ray powder diffraction analysis.