On the basis of a new topology, a novel yttrium metal−organic framework [Y 2 (TPBTM)(H 2 O) 2 ]•xG (TPBTM = N,N′,N″-tris(isophthalyl)-1,3,5-benzenetricarboxamide and G = guest molecule) (NJU-Bai11) has been synthesized and structurally characterized. NJU-Bai11 crystallizes in a chiral space group and in its topological net and exists left of the helical rods, which are constituted from edge-sharing pyramidal polyhedra with points of extension as carboxylic carbon atoms along the a axis. NJU-Bai11 exhibits excellent adsorption capacity for CO 2 (130.0 cm 3 /g at 273 K, 1 bar) and H 2 (160.0 cm 3 /g at 77 K, 1 bar). Remarkably, NJU-Bai11 possesses high H 2 adsorption enthalpy (7.05 kJ/mol), which is approaching the highest value (7.3 kJ/mol) reported among rare-earth metal−organic frameworks (RE-MOFs). In addition, a high selectivity ratio of 30.2 for CO 2 over N 2 makes NJU-Bai11 possess a potential practical application in gas purification.
A p o r o u s m e t a l − o r g a n i c f r a m e w o r k [Cu 6 (BDPP) 3 (H 2 O) 6 ] (BDPP = 3,5-bis(3,5-dicarboxylphenyl)pyridine) (NJU-Bai10) was synthesized. NJU-Bai10 exhibits a high BET surface area of 2883 m 2 g −1 , the highest excess H 2 volumetric adsorption of 48.0 g L −1 (60 bar, 77 K), and a high methane uptake of 198.6 cm 3 cm −3 that surpasses the DOE target.
To explore the effect of terminal groups of tripodal ligands on the photoluminescence behaviors of the complexes, lanthanide (Eu(III), Tb(III)) nitrate complexes with two flexible amide-type tripodal ligands, 2,2',2''-nitrilotris-(N-phenylmethyl)-acetamide (L(I)) and 2,2',2''-nitrilotris-(N-naphthalenemethyl)-acetamide (L(II)) were synthesized and characterized. The general formulas of the complexes are [EuL(I)(2)(C(3)H(6)O)]·(NO(3))(3)·(HCCl(3))·(H(2)O)(4) (1), TbL(I)(2)(NO(3))(3)·2H(2)O (2), EuL(II)(NO(3))(3) (3), and TbL(II)(NO(3))(3) (4). Among them, 1, 3, and 4 were characterized by single-crystal X-ray diffraction. Complex 1 demonstrates a 1 : 2 (ML(2)) capsule type stoichiometry, and the complexes 3 and 4 confirm 1 : 1 (ML) type coordination structures. What is more, the triplet energy levels of L(I) and L(II) are 24,331 and 19,802 cm(-1), which were determined from the phosphorescence spectra of the Gd(III) complexes. Ligand modification by changing the terminal groups alters their triplet energy, and results in a different sensitizing ability towards lanthanide ions. The density functional theory (DFT) calculations of energy levels including HOMO, LUMO, singlet, and triplet energies tuned by the different terminal groups are also discussed in detail, and the trends are almost consistent with the experimental conclusions.
The design of molecular rare-earth complexes with defined architecture is very important in order to investigate structure vs. properties relationships in rare-earth solid-state framework structures, liquid-crystalline materials, sensors or luminescent label design for specific biomolecule interactions. 1 We have been interested in employing self-assembly strategies for supramolecular rare-earth complexes, and have recently used the β-diketonate-type ligand as sensitizers for rare-earth luminescence. 2 In order to achieve supramolecular rare-earth complexes by self-assembly, and to explore the relationship between the structure and the luminescent properties, as one part of our systematic work, herein we report on the synthesis and crystal structure of the lanthanum nitrate complex with N-(2-amino-4-methylpyridinyl)benzoylacetamide.The ligand N-(2-amino-4-methylpyridinyl)benzoylacetamide (L) was prepared according to a procedures from the literature. 3 A solution of 0.3 mmol L in chloroform (2 cm 3 ) was added dropwise to a solution of 0.1 mmol La(NO3)3·6H2O in ethyl acetate (2 cm 3 ) at room temperature. The mixture was stirred at room temperature for 4 h. Also, the precipitated solid complex was filtered, washed, and dried in vacuo over P4O10 for 48 h. Single crystals of the title complex (Fig. 1) were grown from acetone solutions with slow evaporation at room temperature.Single-crystal X-ray diffraction studies of the title complex were performed on a BRUKER SMART 1000 CCD A solid complex of lanthanum nitrate with a β-diketonate-type ligand, N- (2-amino-4-methylpyridinyl)benzoylacetamide, was synthesized. The title complex was crystallized in the monoclinic system, space group C2/c with a = 25.005(5)Å, b = 11.636(2)Å, c = 17.706(3)Å, β = 124.837(1)˚, V = 4228.35(1)Å 3 , Z = 4. The complex has a symmetry of C2, and the geometry of La(III) is a distorted bicapped square antiprism. In the structure of the title complex, a 3D supramolecular network is formed by hydrogen-bond interactions.
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