Two 3D Coordination Frameworks Based on Benzobisimidazole Linkers Generated under Similar Conditions: Synthesis, Structures and Thermal Properties

Herein, we present two benzobisimidazole‐based 3D open coordination framework structures. Single‐crystal X‐ray analyses reveal that the title compounds [Zn(H 2 ‐BBIM)(SO 4 )] · DMSO ( 1 ) (H 2 ‐BBIM = benzobisimidazole; DMSO = dimethyl sulfoxide) and [Co(H 2 ‐BBIM)(SO 4 )(DMSO) 0.5 ] ( 2 ) possess two different framework structures, although both of them have been synthesized under similar conditions. Compounds 1 and 2 exhibit cubic diamondoid and tetragonal CrB 4 topological nets, respectively, in which the four‐connected tetrahedral {MN 2 O 2 } (M II = Zn, Co) coordination units are located at the vertices and the edges are occupied by H 2 ‐BBIM ligands and sulfate anions. Only tetracoordination is observed in 1 , whereas both tetra‐ and pentacoordination is present in 2 . The phase purity of the compounds was ascertained by X‐ray powder diffraction (XRPD) analysis, infrared spectroscopy, and elemental analysis. Variable‐temperature XRPD analysis indicated that 1 and 2 are stable up to 90 and 140 °C, respectively.