KCS

Four copper(I) coordination polymers, {[Cu₄I₄L₂]^.H₂O}_n (1), {[Cu₄I₄L₂]^.2CH₃CN}_n (2), and {[Cu₄I₄L₂]}_n (polymorphs 3 and 4) with 2-(2-benzylthio)ethyl)pyrazine (L), have been prepared by self-assembly reaction between CuI and L. Four coordination polymers 1-4 show supramolecular isomerism by solvent molecules. Compounds 1-3 interconnected by stair-step Cu₄I₄ units are 1D looped chain structures. Remarkably, the crystal structure of CP 4 is 1D triple stranded ladder composed of 1D zigzag chain (CuI)_n and stair-step (Cu₂I₂)_n polymer units. The color of CP 1 changes from red at 298K to yellow at 77K and the color of CP 2 changes from orange at 298K to yellow at 77K. In addition, crystal transformation between 1-4 occurred reversibly by removal of solvent molecular or addition of solvents. The results of our investigation including synthesis, structural characterization, thermal and luminescent properties of four new Cu(I) coordination polymers are presented.