2-D and 3-D organic–inorganic hybrid lanthanide molybdates linking by pyridine-2,5-dicarboxylate

Abstract

Seven organic–inorganic hybrid lanthanide dimolybdates [Ln(H₂O)₆Mo₂O₆(Hpydc)(pydc)]·nH₂O (n = 0: Ln = La^III (1), Ce^III (2), Pr^III (3), Nd^III (4), Sm^III (5); n = 0.5: Ln = Eu^III (6)), and Na_0.5H_0.5[Er(H₂O)₅Mo₂O₆(pydc)₂]·3H₂O (7) (H₂pydc = pyridine-2,5-dicarboxylic acid) have been hydrothermally prepared and further characterized by elemental analyses, X-ray powder diffraction (XRPD), IR spectra, thermogravimetric (TG) analyses, and single-crystal X-ray diffraction. The common feature of 1–7 is that they all consist of Ln^III cations and Mo^IV centers connected by oxygen atoms and H₂pydc ligands. 1–6 show unprecedented 3D 8-connected networks with the Schläfli symbol of (3⁴·4¹⁷·5⁴·6³), while 7 exhibits the 2D 4-connected (4⁵·6) structure. Furthermore, the luminescence properties of 5 and 6 are derived from the combination of Ln cations and H₂pydc ligands, whereas 1–4 and 7 are attributable to H₂pydc ligands.