New Carboxylate Anionic Sm-MOF: Synthesis, Structure and Effect of the Isomorphic Substitution of Sm[sup.3+] with Gd[sup.3+] and Tb[sup.3+] Ions on the Luminescent Properties

Two new compounds, namely {(NMe[sub.2] H[sub.2] )}[Ln(TDA)(HCOO)] 0.5H[sub.2] O, Ln = Sm[sup.3+] (Sm-TDA) and Gd[sup.3+] (Gd-TDA), where TDA[sup.3−] is the anion of 1H-1,2,3-triazole-4,5-dicarboxylic acid (H[sub.3] TDA), were synthesized by the solvothermal method in a DMF:H[sub.2] O mixture. According to single-crystal X-ray diffraction data, the compounds are 3d-MOFs with an anionic lattice and dimethylammonium cations occupying part of the cavities. Based on these compounds, two series of mixed-metal complexes, [NMe[sub.2] H[sub.2] ][Sm[sub.x] Ln[sub.1-x] (TDA)(HCOO)], (x = 0.9 (Sm0.9Ln0.1-TDA), x = 0.8 (Sm0.8-Ln0.2-TDA)…Sm0.02Ln0.98-TDA, Ln = Tb, Gd), were also obtained and characterized by powder XRD. The luminescent properties of the compounds were studied and it was shown that the resulting compounds are two- or three-component emitters with the possibility of fine color tuning by changing the intensities of fluorescence and phosphorescence of the ligand, as well as the luminescence of Sm[sup.3+] and Tb[sup.3+] f-ions.