Two Three-Dimensional Lanthanide Frameworks Exhibiting Luminescence Increases upon Dehydration and Novel Water Layer Involving in Situ Decarboxylation

Abstract

Two three-dimensional polymeric Tb(III) and Yb(III) frameworks, namely, {[Tb3(Hptc)(ptc)(pdc)(H2O)6]·2H2O}n (1) and {[Yb2(ptc)(ox)(H2O)5]·7H2O}n (2) (H4ptc = pyridine-2,3,5,6-tetracarboxylic acid, H2pdc = pyridine-3,5-dicarboxylic acid, ox = oxalate), have been synthesized by a hydrothermal method and characterized by infrared spectra, elemental analysis, powder X-ray diffraction, thermogravimetric analysis, and single-crystal X-ray diffraction. Framework 1 shows an interesting three-dimensional (8,8)-connected net with a Schläfli symbol of (3(3)·4(18)·5(5)·6(2))2(3(6)·4(14)·5(7)·6), while 2 exhibits an unusual (4,8)-connected sqc21 net with a Schläfli symbol of (3(2)·4(2)·5(2))(3(4)·4(8)·5(12)·6(4)). Luminescence studies of 1 reveal that the luminescence intensity increases when the framework is dehydrated.

Unique Chiral Interpenetrating d–f Heterometallic MOFs as Luminescent Sensors

“…The nine-coordinated Tb 3+ is surrounded by six oxygen atoms (O3, O4, O7, O8, O4A, and O7A) from CO 3 2– , two oxygen atoms (O1A and O2A) from the carboxylate group of L – ligand, and one oxygen atom (O6) from water molecules, forming a distorted tricapped trigonal prismic coordination geometry (Figure a). The Tb–O bond lengths range from 2.301 to 2.503 Å, and the O–Tb–O angles fall in the range from 52.68(17) to 149.2(2)°, all of which are comparable to the reported previously . The five-coordinated environments of the Zn 2+ ion are completed by three nitrogen atoms (N1, N2, and N3) from L – ligand and two oxygen atoms from CO 3 2– , displaying a square pyramid geometry (Figure b).…”

Two Novel Lanthanide Metal–Organic Frameworks: Selective Luminescent Sensing for Nitrobenzene, Cu2+, and MnO4–

“…The asymmetry unit contains two crystallographically independent Nd 3+ ions, two fully deprotonated L2 3– ligands, eight water molecules in which five water molecules are coordinated to Nd 3+ ions and three other are lattice water molecules. H 3 L2 ligand was derived from the in situ decarboxylation reaction of H 4 L1 ligand (Scheme ), which may be attributed to the high temperature in the presence of Nd­(III) or Eu­(III) ions because the reactions were carried out under the conditions of high temperature (170 °C). − As shown in Figure a, Nd1 and Nd2 are involved in nine coordinate sites. The Nd1 center is coordinated by one nitrogen atom and six carboxylate oxygen atoms from five L2 3– ligands and two water molecules.…”

Multi-Responsive Luminescent Sensors Based on Two-Dimensional Lanthanide–Metal Organic Frameworks for Highly Selective and Sensitive Detection of Cr(III) and Cr(VI) Ions and Benzaldehyde

“…The asymmetric unit of 4 contains one terbium­(III) ion, one L 2– ligand, one coordinated H 2 O molecule, and one formate anion, which may be obtained in situ during the solvothermal reaction due to the decomposition of DMF. ,, The Tb­(III) center is eight-coordinated with a distorted triangular dodecahedron geometry defined by four O atoms from four different L 2– carboxylate ligands, three O atoms from two formate anions, and one O atom from an individual water molecule (Figure a). Tb–O carboxylate bond lengths vary from 2.3393(12) to 2.5448(12) Å, and the Tb–O water bond length is 2.4834(12) Å, which are comparable to the reported Tb 3+ complexes with carboxylic acids ligands and water molecules. − L 2– and formate ligand adopt μ 4 -η 1 :η 1 :η 1 :η 1 (Figure b) and μ 2 -η 1 :η 2 (Figure c) coordination fashion, respectively. The dihedral angle between benzene ring containing cyano group and the central phenyl ring is 40.421°, and the carboxylate–containing phenyl ring is twisted by 8.511° from the central benzene ring.…”