One-Dimensional Mercury Halide Coordination Polymers Based on A Semi-Rigid -Donor Ligand: Reversible Structural Transformation.

Four one-dimensional (1D) mercury(II) halide coordination polymers have been synthesized by using a semi-rigid -donor ligand, 2,2'-(1,4-phenylene)-bis(-(pyridin-3-yl)acetamide) (1,4-pbpa). While [Hg(1,4-pbpa)Cl₂·CH₃OH], , forms a sinusoidal chain, the complexes [Hg(1,4-pbpa)X₂] (X = Cl, ; Br, ; I, ) are helical. The sinusoidal undergoes reversible structural transformation with helical upon removal and uptake of CH₃OH, which was accompanied with the conformation adjustment of the 1,4-pbpa ligand from anti-anti to syn-anti. Pyridyl ring rotation of the 1,4-pbpa ligand that results in the change of the ligand conformation is proposed for the initiation of the structural transformation.