Two zinc(II) supramolecular isomers of square grid networks formed by two flexible ligands: Syntheses, structures and nonlinear optical properties

Assemblies of 4,4′-dicarboxybiphenyl sulfone (H₂sdba), 1,2-bis(1-imidazolyl- methyl)benzene (bimb) and Zn(NO₃) ₂·6H₂O afford two supramolecular isomers [Zn(sdba)(bimb)]_n of square grid networks depending on the assembly conditions. Single-crystal X-ray diffraction showed that complex 1 entangled into 2-fold parallel interpenetrated sheets containing undulated (4,4) layers, which, furthermore, are polycatenated to generate an unique 3D array. While 2 also possesses [Zn(sdba)(bimb)]_n 2D layer motifs, parallel sets of layer motifs aggregate into 2D + 2D → 3D mutually inclined interpenetrated systems.