Copper(II) Acetate/Bis(4-pyridylthio)methane System: Synthesis, Structural Diversity, and Single-Crystal to Single-Crystal Transformation

Four new coordination compounds have been obtained by the reaction of copper­(II) acetate with SCS [bis­(4-pyridylthio)­methane], namely, [Cu₂(AcO)₄(SCS)] (1), [Cu₂(AcO)₄(SCS)]·solv (2), [Cu₄(AcO)₈(SCS)₅(H₂O)₆]·4H₂O (3), and [Cu₄(OH)₂(AcO)₆(SCS)₂]·10H₂O (4). Structural diversity is achieved by the copper acetate moiety in combination with the flexibility of the SCS ligand. X-ray structural analysis revealed that the compounds have different structural motifs: linear chains in 1, zigzag chains in 2, undulated tetramers in 3, and ladder-like chains in 4. The structures are further connected through hydrogen-bonding interactions with trapped solvent molecules in the crystal lattices (2–4). Guest molecules have a decisive influence on the final crystal system for 2–4. Compound 2 exhibits a temperature-induced single-crystal to single-crystal (SC–SC) transformation, and phase transitions from 2 and 3 to 1 have been found in an irreversible desolvation or recrystallization process.