Synthesis of a Heterometallic [Zn2Ca] Pinwheel Array Stabilized by Amide-Amide Synthons

Abstract

The rational design of heterometallic compounds bearing s-block metal ions have been a difficult task for chemists owing to their lack of preferential geometries. However, some strategies, such as the design of coordinating pockets with different sizes and/or donor atoms, have offered great results. In this work, this strategy has been tested using Ca(II) as an s-block metal ion and a compound previously obtained by our group with the formula [Zn3(μ-ACA)6(4-phpy)2], which contains tetrahedral N,O- and octahedral O-coordinating pockets as a model structure. From this work, the corresponding heterometallic compound with the formula [Zn2Ca(μ-ACA)6(4-phpy)2]·EtOH (1) has been successfully synthesized, and fully characterized, and its crystal structure has been elucidated. Furthermore, we have compiled all the crystal structures containing [Zn2M] pinwheel secondary building units (SBUs), where M stands for an s-block metal ion, and the observed tendencies, as well as the promising applications as template SBUs for the preparation of 1D–3D coordination polymers, have been discussed. Finally, solid-state UV-Vis and photoluminescence have been recorded and compared with the homometallic [Zn3(μ-ACA)6(4-phpy)2] compound.

Structural Landscape of α-Acetamidocinnamic Acid Cocrystals with Bipyridine-Based Coformers: Influence of Crystal Packing on Their Thermal and Photophysical Properties

“…To date, only one dihydrate and one cocrystal have been reported. − The dihydrate structure connected the HACA molecules through masked synthons of water clusters supported by acid···amide interactions, , whereas the cocrystal contained 2-pyridone (Pdon), presenting Pdon···acid and amide···amide synthons . However, previous studies performed in the group with coordination compounds suggested a tendency of the HACA molecules toward being ordered by amide···amide patterns, leading to supramolecular chains or cycles depending on the synthetic conditions. − …”