Solvothermal synthesis, crystal structures and properties of two new magnesium coordination polymers of (l)-malic acid

Two new three dimensional magnesium coordination polymers of formula, [Mg4(HL-MA)2(HCO2)2(OH)2]∙(EtOH)∙2(H2O) (1), and [Mg(HL-MA)(H2O)] (2), (H3L-MA = l-malic acid) have been solvothermally synthesized in order to study the coordination properties of (L)-malic acid and the structural features of the resulting coordination polymers (CPs). The structures of the newly synthesized CPs have been determined by single-crystal X-ray diffraction analysis and further characterized by various analytical and spectroscopic techniques. The single crystal structure analysis showed that the complexes, 1 and 2 form three-dimensional frameworks. Topological analysis revealed that the 1 can be described as a new 4-nodal net with Schläfli symbol of {43.62.8}{43}{47.63}{47.65.82.10} and 2 can be described as a ‘sra’ net. The ligand acted as a bi-anionic hepta-dentate and bi-anionic penta-dentate in 1 and 2 respectively. Moreover, the solid-state luminescent spectra of the two Mg(II) complexes indicated that the two complexes emitted their own characteristic sensitized luminescence.