Cu(I)-iodide coordination polymers with aromatic thioamides

The reaction between 4-pyridin-thiobenzamide (PyTBA) with CuI and KI aqueous solution in acetone or THF as solvents under slow diffusion, gives rise to the formation of single crystals of two coordination polymers of formula [CuIPyTBA]n·nS (S= acetone (1); ⅓THF (2)). X-ray diffraction analysis of compounds 1 and 2 shows that they consist of a 2D layered network formed of Cu2I2 units linked both by pyridinic N and S atoms from two PyTBA ligands. The metal-organic network creates voids that are occupied by the solvent molecules. The similar direct reaction carried out at room temperature between a mixture of CuI and PyTBA in acetone leads to the isolation of a microcrystalline red solid which is a mixture of [CuIPyTBA]n·n acetone (1) and [CuIPyTBA]n (3). The thermal treatment of this mixture allows to isolate 3 in pure form. The structure from X-ray diffraction data of 3 reveals that it consists of a 3D interpenetrated non-porous network, of formula [CuIPyTBA]n (3). The exposition of 3 to acetone leads to a mixture of 1 and 3, while the heating of this mixture produces a complete transformation to 3. This desolvated-solvated transformation observed in 3 has been analysed and rationalized based on the X-ray structures of the coordination polymers.