Controlled Reversible Crystal Transformation of Cu(I) Supramolecular Isomers

Four copper­(I) coordination polymers (CPs), {[CuI<b>L</b>]·CH₃CN]}_<i>n</i> (<b>1</b>), {[CuI<b>L</b>]·CHCl₃}_<i>n</i> (<b>2</b>), {[CuI<b>L</b>]·CH₂Cl₂}_<i>n</i> (<b>3</b>), and [CuI<b>L</b>]_<i>n</i> (<b>4</b>), were prepared by self-assembly reactions between CuI and (2-pyrazinylcarbonyl)­thiomorpholine (<b>L</b>). CPs <b>1</b>–<b>4</b> are interconnected by rhomboid Cu–I₂–Cu units. CPs <b>1</b> and <b>4</b> have one-dimensional loop-chain structures, and <b>2</b> and <b>3</b> adopt two-dimensional network structures. CPs <b>1</b>–<b>4</b> are pseudopolymorphic supramolecular isomers. CPs <b>2</b>′ and <b>3</b>′ are prepared by removal of solvate molecules from CPs <b>2</b> and <b>3</b>, which are polymorphic supramolecular isomers with CP <b>4</b>. Reversible crystal-to-crystal transformations were observed under appropriate conditions such as solvent or heat