Synthesis, Structure, Photochemical [2 + 2] Cycloaddition, Transformation, and Photocatalytic Studies in a Family of Inorganic–Organic Hybrid Cadmium Thiosulfate Compounds

Three new inorganic–organic hybrid cadmium thiosulfate compounds, [Cd(C₁₂H₁₁N₂)₂(H₂O)(S₂O₃)₂] (I), [Cd₂(C₁₂H₁₀N₂)₃(H₂O)₄(S₂O₃)₂] (II), and [Cd(C₁₂H₁₀N₂)S₂O₃] (III), have been prepared using bispyridylethene (bpe) as a coligand. The compounds have connectivity between the Cd centers, the bpe, and the thiosulfate units, giving rise to molecular (zero) (I), two (II), and three dimensionally (III) extended structures. The formation of Cd₄S₄ tetrameric cluster units in III is noteworthy. The two-dimensional compound, II, was found to be a reactive intermediate and transforms to the three-dimensional compound, III, as a function of reaction time. The [2 + 2] photochemical reactions carried out on all of the compounds suggest the facile formation of the cyclized products. The photodimerization studies resulted in a one-dimensional structure (Ia) from the molecular complexes of I and rigid cyclized products in II and III. The present study illustrates the usefulness of the photochemical method as a viable alternative for the postsynthetic structural modifications in inorganic–organic hybrid compounds. The synthesized compounds also exhibit reasonable activity as a photocatalyst. The present study provides the scope and optimism for employing the thiosulfate anion as an efficient network builder in the design of inorganic–organic hybrid compounds.