Alkali and alkaline earth coordination polymers constructed from benzene‐1,2,4,5‐tetracarboxylic acid and flexible dicarboxylate acid ligands: syntheses, structures and spectroscopic and thermal properties

• Published in: Acta crystallographica. Section C, Crystal structure communications Crystal structure communications, 2021-02, Vol.77 (2), p.90-99
• Main Authors: Lifa, Said, Trifa, Chahrazed, Bouacida, Sofiane, Boudaren, Chaouki, Merazig, Hocine
• Format: Article
• Language: English
• Subjects: Acids; alkali; alkaline earth; Alkaline earth metals; Benzene; benzenetetracarboxylic acid; Calorimetry; Coordination compounds; Coordination polymers; Crystal structure; Decomposition; Differential scanning calorimetry; Displays; DSC analysis; flexible dicarboxylate ligand; Fumaric acid; Hirshfeld surface; Hydrocarbons; Infrared spectroscopy; metal coordination polymer; Metal oxides; MOF; Oxalic acid; Polymers; Potassium; Strontium; Thermal properties; Thermodynamic properties; thermogravimetric analysis; Topology; X-ray diffraction
• ISSN: 2053-2296; 0108-2701; 2053-2296; 1600-5759
• DOI: 10.1107/S2053229621000085

Two new metal coordination complexes, namely, poly[aqua(μ6‐benzene‐1,2,4,5‐tetracarboxylic acid‐κ8O1:O1,O2:O2′:O4:O4,O5:O5′)(μ‐but‐2‐enedioato‐κ2O1:O4)potassium(I)], [K2(C4H2O4)(C10H6O8)(H2O)2]n or [K2(fum)(H4btec)(H2O)2]n, (1), and poly[aqua(μ8‐2,5‐dicarboxybenzene‐1,4‐dicarboxylato‐κ12O1:O1′,O2:O2,O2′:O2′:O4:O4′,O5:O5,O5′:O5′)(μ‐ethanedioato‐κ4O1,O2:O1′,O2′)strontium(II)], [Sr2(C2O4)(C10H4O8)(H2O)2]n or [Sr2(ox)(H2btec)(H2O)2]n, (2) (H4btec = benzene‐1,2,4,5‐tetracarboxylic acid, H2btec = 2,5‐dicarboxybenzene‐1,4‐dicarboxylate, fum = fumarate and ox = oxalate), have been obtained under hydrothermal conditions by reacting the different alkali and alkaline earth metal salts with H4btec, fumaric acid (H2fum) and oxalic acid (H2ox). Complexes (1) and (2) were structurally characterized by single‐crystal X‐ray diffraction, IR and UV–Vis spectroscopy, powder X‐ray diffraction (PXRD) and thermogravimetic analysis–differential scanning calorimetry (TGA–DSC). Complex (1) displays a two‐dimensional (2D) layer with the K+ ion in a distorted pentagonal bipyramidal geometry and exhibits a uninodal 6‐connected hxl/Shubnikov plane net (3,6) with {36.46.53} topology. Complex (2) displays a three‐dimensional (3D) network structure, in which the Sr2+ ion is in a distorted monocapped square antiprism geometry. The framework possess a binodal (5,8)‐connected net with the Schläfli symbol {32.410.58.64.74}{32.46.52}2. The 3D Hirshfeld surfaces and 2D fingerprint plots show that the main interactions are the O…H/H…O intermolecular interactions. Moreover, the thermal decompositions of (1) and (2) in the temperature range 303–1273 K revealed that they both decompose in three steps and transform to the corresponding metal oxide. Two new alkali/alkaline earth coordination polymers were prepared from benzene‐1,2,4,5‐tetracarboxylic acid as a rigid polycarboxylate metal linker and two types of flexible dicarboxylate ligands as the second linker under similar hydrothermal reaction conditions. The polymers were structurally characterized by single‐crystal X‐ray diffraction. The flexible dicarboxylate ligands play an important role in tuning the detailed structures and characteristics of the complexes.