Strontium‐Carboxylate‐Based Coordination Polymers: Synthesis, Structure and Dielectric Properties. Issue 16 (26th April 2019) - Balendra,
Abstract: Solvothermal reaction of strontium ions with selected N‐containing and/or V‐shaped carboxylates led to the crystallization of six new coordination polymers: [Sr( 2‐PZC )2 ] (1 ), [Sr( 2, 5‐PDC )(DMF)] (2 ), [Sr( 2, 5‐PDC )(DMA)] (3 ), [Sr( IDA )2 ] (4 ), [Sr( SBA )(H2 O)2 ].DMF (5 ) and [Sr2 ( FBA )2 (H2 O)2 (DMA)2 ].DMA (6 ) where, 2 ‐ PZC =2‐pyrazinecarboxylate, 2, 5 ‐ PDC =2, 5‐pyridinedicarboxylate, IDA =iminodiacetate, SBA =4, 4′‐sulfonyldibenzoate and FBA= 4, 4′ (hexafluoroisopropylidene)bis(benzoate). Crystal structures were determined by single‐crystal X‐ray diffraction analysis and further characterized by powder X‐ray diffraction, elemental analysis, IR spectra, and TG analyses. Single crystal of 1 shows the occurrence of distorted rings made of twelve strontium carboxylate polyhedra connected in 3D. The structures of 2, 3, 5 and 6 are characterized by the presence of strontium carboxylate columns made of edge‐sharing SrOn polyhedra but connected differently to each other through organic linkers. The solids 2 and 3 are isostructural and contain rhombic channels which are occupied by the coordinated solvents. In solid 4, strontium occurred in a rare octahedral geometry bridged by IDA 2− extending into 2D sheets. The structural features of 5 and 6 synthesized using V‐shaped ligands show 2D square‐shaped channel network. All the solids showed dielectric constants in the range 8–20. The solvent‐less 1 showed a relatively low dielectric constant (∼8) in comparison to 2, 3 and 4 . The solids 5 and 6 with flexible ligands showed higher dielectric constants (∼17 and ∼20 respectively). Abstract : Six new coordination polymers (CPs) have been assembled through strontium(II)⋅⋅⋅carboxylate coordination interaction. Structure property correlation of dielectric behaviour of the solids suggests that coordination mode of metal, the structure of the ligands and inclusion/absence of polar solvents in the structure significantly influence the intrinsic dielectric behaviour.