High-dimensional frameworks dependent on coordination mode of ligand controlled by acidity of reaction solution. Syntheses, structures, magnetic and fluorescence properties of eight new compounds

Abstract

Eight new compounds [Ln 4 (HL) 2 (L) 2 (H 2 O) 14 (H 2 W 12 O 40 )]$nH 2 O (Ln ¼ La (1), Pr (3), n ¼ 14; Ce (2), 5), Ce (6), Pr (7), Nd (8)) were conventionally synthesized. Compounds 1-4 are isomorphic and show a 2D structure with (3 2 6 2 7 2 )(3 1 4 2 5 1 6 2 ) 2 topology, and compounds 5-8 are also isomorphic and have a 3D framework constructed from [H 2 W 12 O 40 ] 6À clusters and lanthanide-organic-frameworks. Compounds 1 and 5, 2 and 6, 3 and 7, and 4 and 8 were obtained in the same solution systems, respectively. The formation of these compounds with two types of multidimensional structures mainly depends on the solution acidity and the coordination modes of the ligands. Furthermore, thermal properties of 1-8, fluorescence properties of 4 and 8, and magnetic properties of 2-4 have been examined. Experimental Materials and general methodsAll reagents of analytical grade were obtained commercially. Ln(NO 3 ) 3 (Ln ¼ Pr and Nd) was prepared by adding

3D lanthanide–transition-metal–organic frameworks constructed from tetranuclear {Ln4} SBUs and Cu centres with fsc net

“…It is well known that anions play an important role in the structural control for self-assembly. 16 The most common anions, such as silicates, 17 phosphates, 18 polymolybdate 19 and polytungstate 20 have been employed in the inorganic-organic MOFs. However, these anions have rarely been used as auxiliary bridges to build Ln SBUs so far, it should be feasible to introduce these anions to construct Ln SBUs.…”

Solvent-controlled 3D lanthanide–polyoxometalate frameworks: reduction and stabilization of Ag nanocomposites and catalytic properties

“…The weight loss of 17.61% (calcd 17.29%) from 163 to 556 °C corresponds to the decomposition of organic ligands and the formation of oxycarbonate La 2 O 2 (CO 3 ). 38 General procedure for synthesis of K 4 Ce 3 (HIDC) 3 (IDC) 3 (H 2 O) 3 (SiW 12 O 40 )•6H 2 O (2). The synthetic procedure was prepared in the same way as 1, except using CeCl 3 •7H 2 O to replace LaCl 3 •7H 2 O. Yellow block crystals were obtained.…”

“…The weight loss of 17.66% (calcd 17.21%) from 161 to 550 °C corresponds to the decomposition of organic ligands and the formation of oxycarbonate La 2 O 2 (CO 3 ). 38 General procedure for synthesis of La 4 (HIDC) 4 (SiW…”

Effect of ring coordination of pyridine-3,5-dicarboxylate and metatungstate to Ln ions on metatungstate structure: Synthesis, structure and optical property of four new compounds

“…In this field, a branch is to construct multidimensional organic-inorganic hybrid materials via combination of POMs with MOFs [16][17][18]. Among the various types of polyanions, the a-metatungstate polyanion [H 2 W 12 O 40 ] 6 À (W 12 ) possess higher charge density and some structural features, and can provide a variety of possibilities of intermolecular linkages [19][20][21]. Hence, the construction of high-dimensional hybrid materials based on the W 12 clusters and Ln coordination complexes is a research topic.…”