High-Pressure Selective Topotactic Synthesis of Ordered Trans-Polymeric CS2 in a Zeolite

• Published in: Inorganic chemistry Vol. 64; no. 25; pp. 12762 - 12767
• Main Authors: Santoro, Mario, Romi, Sebastiano, Alabarse, Frederico G., Hermet, Patrick, Haines, Julien
• Format: Journal Article
• Language: English
• Published: American Chemical Society 30.06.2025
• ISSN: 0020-1669; 1520-510X; 1520-510X
• DOI: 10.1021/acs.inorgchem.5c01685

High-pressure polymerization of CS2 leads to structurally and stoichiometrically disordered solids, making characterization of the products and of reaction mechanisms challenging. This is due to the multiplicity of chemical pathways that CS2 is subject to in the free space. We reduced this multiplicity by constraining polymerization in a confined space. We inserted liquid CS2 in the one-dimensional pores of the all-siliceous zeolite Theta-One, subjected the mixture to maximum temperatures and pressures of 250 °C and 14 GPa, and recovered a darkened sample at ambient conditions. Synchrotron X-ray diffraction was performed on the materials. Full structural refinements, using ab initio calculated structures as starting models, show that CS2 in the zeolite undergoes selective topotactic polymerization, resulting in the ordered trans-isomer of the long-sought-after Bridgman’s black polymer (-(CS)-S-) n . We provide physical insight into the reaction mechanism by proposing that it consists of a molecular bending followed by addition. The trans-polymer forms spontaneously from the unstable, confined monomer upon relaxation in ab initio calculations.