ABSTRACT
A series of new alkaline-earth metal diphosphonate frameworks were successfully synthesized under solvothermal reaction condition (160 °C, 3 d) using 1-hydroxyethylidene-1,1-diphosphonic acid (CH3C(OH)(H2PO3)2, hedpH4) as a diphosphonate building block and Mg(II), Ca(II), Sr(II), or Ba(II) ions as alkaline-earth metal ion centers in water, dimethylformamide, and/or EtOH media. These diphosphonate frameworks, (H2NMe2)4[Mg(hedpH2)3]·3H2O (1), (H2NMe2)2[Ca(hedpH2)2] (2), (H2NMe2)2[Sr3(hedpH2)4(H2O)2] (3), and [Ba3(hedpH2)3]·H2O (4) exhibited interesting structural topologies (zero-, one-, two-, and three-dimensional (0D, 1D, 2D, and 3D, respectively)), which are mainly depending on the metal ions and the solvents used in the synthesis. The single-crystal analysis of these newly synthesized compounds revealed that 1 was a 0D molecule, 2 has 1D chains, 3 was a 3D molecule, and 4 has 2D layers. All compounds were further characterized using thermogravimetric analysis, solid-state (31)P NMR, powder X-ray diffraction analysis, UV-vis spectra, and infrared spectroscopy. In addition, Eu(III)- and Tb(III)-doped compounds of 1-4, namely, (H2NMe2)4[Ln(x)Mg(1-x)(hedpH2)2(hedpH(2-x))]·3H2O (1Ln), (H2NMe2)2[Ln(x)Ca(1-x)(hedpH2)(hedpH(2-x))] (2Ln), (H2NMe2)2[Ln(x)Sr(3-x)(hedpH2)3(hedpH(2-x))(H2O)2] (3Ln), and [Ln(x)Ba(3-x)(hedpH2)2(hedpH(2-x))]·H2O (4Ln) (where Ln = Eu, Tb), were synthesized, and their photoluminescence properties were studied. The quantum yield of 1Eu-4Eu was measured with reference to commercial red phosphor, Y2O2S:Eu(3+) (YE), and the quantum yield of terbium-doped compounds 1Tb-4Tb was measured with reference to commercial green-emitting phosphor CeMgAl10O17:Tb(3+). Interestingly, the compound 2Eu showed very high quantum yield of 92.2%, which is better than that of the reference commercial red phosphor, YE (90.8%).
ABSTRACT
The asymmetric unit of the title complex, [Sr(5)(C(8)H(4)O(4))(4)(HCO(2))(2)](n), contains three independent Sr(II) ions, one of which is located on an inversion center. In the crystal, the Sr(II) ions (coordination numbers 8, 9 and 12) are connected by two crystallographically distinct benzene-1,2-dicarboxyl-ate ligands and one formate ligand, forming a two-dimensional polymer parallel to (001).
ABSTRACT
In the title compound, [Sr(2)(C(8)H(6)O(8))(H(2)O)(4))](n), the Sr(II) ion is coordinated by six O atoms of four symmetry-related ligands and two water mol-ecules in a distorted bicapped trigonal-prismatic environment. The butane-1,2,3,4-tetra-carboxyl-ate ligands lie on inversion centers and bridge Sr(II) ions, forming a three-dimensional network. Within the three-dimensional structure, there are O-Hâ¯O hydrogen bonds involving the water mol-ecules and carboxyl-ate O atoms.
ABSTRACT
In the title compound, {[Sr(C(12)H(10)O(12))(H(2)O)]·H(2)O}(n), the Sr(II) ion is coordinated by six O atoms of five symmetry-related 3,4,5,6-tetra-carb-oxy-cyclo-hexane-1,2-dicarboxyl-ate ligands and one water mol-ecule in a slightly distorted monocapped trigonal-prismatic environment. The ligands bridge the Sr(II) ions, forming a two-dimensional structure. In the crystal, O-Hâ¯O hydrogen bonds further connect the structure into a three-dimensional network. The H atoms of two of the carboxyl groups were refined as half-occupancy.
