Solid-State Syntheses of Coordination Polymers by Thermal Conversion of Molecular Building Blocks and Polymeric Precursors

The syntheses and crystal structures of a mononuclear cadmium complex and five novel coordination polymers based on 1,2,4-triazolyl benzoates are presented. The compounds ∞3[Cd­(H-Me-trz-pba)2] (2), ∞3[Cd­(Me-3py-trz-pba)2] (4), and ∞3[Zn­(H-Me-trz-pba)2] (6) can be obtained by solvothermal synthesis or simple heating of the starting materials in appropriate solvents, and are also accessible by thermal conversion of the complex [Cd­(H-Me-trz-pba)2(H2O)4] (1), the one-dimensional (1D) coordination polymer ∞1[Cd­(Me-3py-trz-pba)2(H2O)2]·H2O (3), and the porous three-dimensional (3D) framework ∞3[Zn­(H-Me-trz-pba)2]·4H2O (5), respectively. The driving force for these conversions is the formation of thermally stable, nonporous, crystalline 3D coordination polymers. The structural transformations are accompanied by the loss of water and reveal significant changes of the coordination spheres of the metal ions caused by a rearrangement of the triazolyl benzoate ligands. Compounds 2, 4, 5, and 6 exhibit 4- and 5-fold interpenetration of diamondoid networks (dia) and are thermally stable up to 380 °C.