Two new isomeric zinc(II) metal-organic frameworks based on 1,5-bis(2-methyl-1H-imidazol-1-yl)pentane and 5-methylisophthalate ligands.

Many factors, such as temperature, solvent, the central metal atom and the type of coligands, may affect the nature of metal-organic frameworks (MOFs) and the framework formation in the self-assembly process, which results in the complexity of these compounds and the uncertainty of their structures. Two new isomeric Zn metal-organic frameworks (MOFs) based on mixed ligands, namely, poly[[μ-1,5-bis(2-methyl-1H-imidazol-1-yl)pentane-κN:N](μ-5-methylisophthalato-κO:O)zinc(II)], [Zn(CHO)(CHN)], (I), and poly[[μ-1,5-bis(2-methyl-1H-imidazol-1-yl)pentane-κN:N](μ-5-methylisophthalato-κO:O:O)(μ-5-methylisophthalato-κO:O:O,O)dizinc(II)], [Zn(CHO)(CHN)], (II), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and thermogravimetric analysis. Complex (I) displays a two-dimensional layer net, while complex (II) exhibits a twofold interpenetrating three-dimensional framework. Both complexes show high stability and good fluorescence in the solid state at room temperature.