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Two polymorphic forms of a mixed zinc/copper biquinoline dihydrogenphosphate
Yanko Moreno1, Patricio Hermosilla, María Teresa Garland
1Departamento de Química Analítica e Inorgánica, Facultad de Ciencias Químicas, Universidad de Concepción, Casilla 233, Concepción, Chile. ymoreno@udec.cl
Summary
This study presents two polymorphic forms of mixed zinc/copper biquinoline dihydrogenphosphate. The structures feature similar monomeric units but differ in intermolecular hydrogen bonding and crystal packing, with no detected stress from solid solution formation.
Area of Science:
- Inorganic Chemistry
- Crystallography
- Materials Science
Background:
- Mixed metal phosphates are of interest for their diverse structural and functional properties.
- Biquinoline ligands offer unique coordination environments for metal ions.
- Polymorphism in coordination compounds can influence material characteristics.
Purpose of the Study:
- To synthesize and characterize two polymorphic forms of a mixed zinc/copper biquinoline dihydrogenphosphate.
- To investigate the structural differences and intermolecular interactions in these polymorphic forms.
- To assess the impact of Zn/Cu solid solution formation on the crystal structure.
Main Methods:
- Single-crystal X-ray diffraction to determine the crystal structures.
- Elemental analysis to confirm the composition and Zn/Cu ratio.
- Powder X-ray diffraction for phase identification and structural comparison.
Main Results:
- Two distinct polymorphic forms of [Zn(x)Cu(1-x)(H(2)PO(4))(2)(C(18)H(12)N(2))] were identified with x = 0.88 and 0.90.
- Both structures exhibit nearly identical monomeric units with tetrahedral coordination around the metal centers.
- Differences were observed in intermolecular hydrogen bonding and crystal packing arrangements.
- No significant structural stress was detected due to the formation of the Zn/Cu solid solution.
Conclusions:
- The polymorphic forms are primarily differentiated by their supramolecular assembly through hydrogen bonding.
- The biquinoline ligand effectively chelates the mixed metal centers in a tetrahedral geometry.
- Zn/Cu solid solution formation in this system does not induce significant lattice strain.
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