The mechanochemical conversion of potassium coordination polymer nanostructures to interpenetrated sodium coordination polymers with halogen bond, metal–carbon and metal–metal interactions

Abstract

Two new coordination polymers, namely, [Na₂(μ₄-TBT)(H₂O)₄]_n (1) and [K₂(μ₄-TBT)(H₂O)₄]_n (2) [H₂TBT = tetrabromoterephthalic acid] were synthesized and their crystal structures were characterized via the single-crystal X-ray diffraction technique. In both of them, halogen bond, metallophilic and hydrogen bonding interactions were observed. Compound 1 exhibited the perpendicular 2D → 3D interpenetration of the (4,4) square network to a 3D supramolecular structure. Compound 2 showed weak metal⋯carbon interactions. These two compounds were synthesized via the sonochemical reaction, and their solid-state mechanochemical conversions to each other were investigated with IR spectroscopy as well as PXRD, EDAX, TGA and SEM analyses. Also, the irreversible conversion of 2 to 1 was observed.