ZINC(II) AND CADMIUM(II) METAL-ORGANIC FRAMEWORKS BASED ON THE AMIDE- FUNCTIONALIZED TETRACARBOXYLATE LIGAND: SYNTHESIS, CRYSTAL STRUCTURE, AND LUMINESCENT PROPERTIES

By heating cadmium(II) and zinc(II) nitrates with 5-(3,5-dicarboxybenzoylamino)-isophthalic acid in mixed solvents [Cd 2 (H 2 O) 3 (nmp)(L)]·NMP ( 1 ), (H 2 NMe 2 ) 2 [Cd 3 (L) 2 ] ( 2 ), and (H 2 NMe 2 ) 2 [Zn 2.5 (HL)(L)] ( 3 ) metal-organic frameworks are obtained. The compositions and structures of these compounds are determined by X-ray crystallography. Compound 1 has a layered structure, and isostructural 2 and 3 form 3D frameworks. Pores in compound 1 are filled with disordered solvent molecules, and in anionic 3D frameworks of 2 and 3 they contain dimethylammonium cations. The compositions of isostructural compounds 2 and 3 differ because the position of one of the zinc cations is half populated in 3 , while the ligand in 3 is partially protonated. In 1 , 5-(3,5-dicarboxybenzoylamino)-isophthalic ligands are in an eclipsed conformation; and in 2 and 3 , they are in a crossed conformation. The photoluminescent properties are studied in the cadmium(II) and zinc(II) frameworks.