Two-dimensional metal-organic framework constructed from 4,4′-bipydine and 1,2,4-benzenetricarboxylate: Synthesis, structure and magnetic properties

Two new copper coordination polymers generated from mixed organic ligands 4,4′-bipydine and 1,2,4-benzenetricarboxylate [Cu₃(1,2,4-BTC)₂(4,4′-bipy)(H₂O)₄] 1 and [Cu(1,2,4-HBTC)(4,4′-bipy)] 2 (1,2,4-BTC=1,2,4-benzenetricarboxylate) have been prepared hydrothermally and characterized by single crystal X-ray diffraction. Compound 1 crystallizes in the noncentrosymmetric space group Fdd2, with , , , , and Z=8. Its structure contains two different one-dimensional (1-D) chains for the Cu ions, namely and ; the carboxylate of 1,2,4-BTC ligands links the two different 1-D chains into an interesting steplike neutral framework. Compound 2 crystallizes in the monoclinic space group P2₁/n, with a=9.9806(8), b=16.5512(16), , β=99.375(5)°, , Z=4. Its structure contains novel paddle-wheel clusters Cu₂(CO₂)₄(4,4′-bipy)₂ as SBUs which are further linked by monoprotonated 1,2,4-BTC ligands into a 2-D neutral framework. The magnetic behaviors of both compounds have been studied.     

Low-temperature flux syntheses and characterizations of two 1-D anhydrous borophosphates: Na3B6PO13 and Na3BP2O8

Two new anhydrous sodium borophosphates with one-dimensional structure, Na₃B₆PO₁₃(1) and Na₃BP₂O₈(2), were synthesized by low-temperature molten salts techniques using boric acid and sodium dihydrogen phosphate as flux, respectively. The crystal structures were solved by means of single-crystal X-ray diffraction (1, orthorhombic, Pnma (no. 62), , , , Z=4; 2 , monoclinic, C2/c (no. 15), , , , β=92.492(5)°, Z=8). Compound 1 is characterized by an infinite chain of containing eight-membered rings in which all vertexes of borate groups contribute to interconnection. Compound 2 reveals an infinite straight chain built of vertex-sharing four-membered rings, and chains in neighboring layers arranged along different orientations. The relations between structures and the synthetic conditions with only traced water are discussed.     

Synthesis, structure and optical limiting effect of a novel inorganic-organic hybrid polymer containing mixed chains of copper(I)/iodine

In this paper, treatment of N-ethyl-benzo[f]quinolium (ebq) iodide and CuI with excess KI afforded an unusual coordination polymer [(ebq)₂(Cu₃I₄)(CuI₂)]_n (1). 1 crystallizes in tetragonal system, space group P4(2)bc with cell parameters of , , , Z=8, , R₁=0.0447 and wR₂=0.0974. A highly interesting feature of 1 is its presence of mixed types of chains [ and chain] in one crystal lattice based on supramolecular self-assembly directed by cations. The infinite chains and in 1 could be described as the edge-sharing arrangement of CuI₄ tetrahedron. Furthermore, IR, EA, UV-Vis, thermal analysis and optical limiting measurements were adopted to characterize polymer 1. The optical limiting experiment shows that the present polymer exhibits a large optical limiting capacity.     

Synthesis and characterization of the rare-earth dicyanamides Ln[N(CN)2]3 with Ln=La, Ce, Pr, Nd, Sm, and Eu

The rare-earth dicyanamides Ln[N(CN)₂]₃ (Ln=La, Ce, Pr, Nd, Sm, Eu) were obtained via ion exchange in aqueous medium and subsequent drying: The crystal structures were solved and refined based on X-ray powder diffraction data and they were found to be isotypic: Ln[N(CN)₂]₃; Cmcm (no. 63), Z=4, Ln=La: , , ; Ce: , , ; Pr: , , ; Nd: , , ; Sm: , , ; Eu: , , ). The compounds represent the first dicyanamides with trivalent cations. The Ln³⁺ ions are coordinated by three bridging N atoms and six terminal N atoms of the dicyanamide ions forming a three capped trigonal prism. The structure type is related to that of PuBr₃. The novel compounds Ln[N(CN)₂]₃ have been characterized by IR and Raman spectroscopy (Ln=La) and the thermal behavior has been monitored by differential scanning calorimetry (Ln=Ce, Nd, Eu).     

[Zn2(HPO3)2(H2PO3)][C3H5N2] and [Zn2(HPO3)3][C4H7N2]2·2H2O: Two new layered zinc phosphites with double 12-membered rings templated by imidazole and 2-methylimidazole

Two new zinc phosphites [Zn₂(HPO₃)₂(H₂PO₃)][C₃H₅N₂] 1 and [Zn₂(HPO₃)₃][C₄H₇N₂]₂·2H₂O 2 have been hydrothermally synthesized templated by imidazole and 2-methylimidazole. Single-crystal X-ray diffraction analysis reveals that the two compounds have the similar inorganic framework structures, which both exhibit 2D double layer structures with double 12-membered rings. Due to the different space-filling effect of the guest molecules, the stacking mode of adjacent layers and the arrangement mode of the organic amines are distinct. In 1, the adjacent layers are stacked in an -ABAB- sequence and monoprotonated imidazole molecules sit in the middle of 12MR windows, while in 2, the layers are stacked in an -AAAA- pattern. Monoprotonated 2-methylimidazole molecules occupy two different sites, one inserts into 12MR and the other resides in the interlayer region. Crystal data for 1: triclinic, P-1, , , , α=114.71(3)°, β=92.78(3)°, γ=113.04(3)°, , Z=2; for 2: triclinic, P-1, , , , α=68.244(7)°, β=76.143(7)°, γ=63.113(6)°, , Z=2.     

An anionic chromogenic sensor based on the competition between the anion and a merocyanine solvatochromic dye for calix[4]pyrrole as a receptor site

The interaction of Brooker’s merocyanine (BM), a merocyanine dye, with calix[4]pyrrole (CP) was studied in acetonitrile. BM is violet in solution, but its interaction with CP changes the color of the solution due to the formation of CP-BM species associated through hydrogen bonding. A displacement assay was then carried out in the presence of different anions (F⁻, Cl⁻, Br⁻, I⁻, , , and ). It was verified that F⁻, and to a lesser extent Cl⁻ and , displace BM through the formation of a complex with CP, coloring the solution. Addition of makes the solution almost colorless because it is sufficiently acidic to transfer a proton to BM, removing it from the receptor site in CP and protonating the dye, thereby allowing the visual detection of the anion in relation to the other anions.     

Crystal structures and spectroscopic properties of a new zinc phosphite cluster and an unexpected chainlike zinc phosphate obtained by hydrothermal reactions

A new zinc phosphite cluster, Zn₂(4,4′-dmbpy)₂(H₂PO₃)₄1, and a new chainlike zinc phosphate, Zn₂(5,5′-dmbpy)₂(HPO₄)(H₂PO₄)₂2, have been synthesized under hydrothermal conditions (4,4′-dmbpy=4,4′-dimethyl-2,2′-dipyridy, 5,5′-dmbpy=5,5′-dimethyl-2,2′-dipyridy). Compound 1 is a molecular zinc phosphite constructed from ZnO₃N₂ trigonal bipyramids, H₂PO₃ pseudo-pyramids and 4,4′-dmbpy ligands. Compound 2 possesses a 1D chainlike framework constructed from ZnO₃N₂ trigonal bipyramids, HPO₄ tetrahedra, H₂PO₄ tetrahedra and 5,5′-dmbpy ligands. Both compounds 1 and 2 exhibit intensive photoluminescence originated from the intraligand π-π* transitions. Crystal data: 1, monoclinic, P2₁/n, , , , β=110.857(3)°, , Z=2, R1=0.0297, wR₁=0.0801; 2, triclinic, P-1, , , , α=64.995(9)°, β=65.952(9)°, γ=65.296(8)°, , Z=2, R₁=0.0418, wR₁=0.1010.     

Syntheses and crystal structures of three new borates templated by transition-metal complexes in situ

Three new cobalt borate compounds, [Co(DIEN)₂][B₅O₆(OH)₄]₂ (DIEN=diethylenetriamine) (1), [B₅O₇(OH)₃Co(TREN)] (TREN=tris(2-aminoethyl)amine) (2), and [Co₂(TETA)₃][B₅O₆(OH)₄]₄ (TETA=triethylenetetramine) (3) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR, elemental analysis and thermogravimetry. The structures exhibit interesting 3D supramolecular hydrogen-bonded architectures, involving the similar borate polyanion [B₅O_6+n(OH)_4−n]⁽ⁿ⁺¹⁾⁻(n=0 for 1 and 3, and n=1 for 2) and the templating transition metal complexes which are generated in situ under mild solvothermal conditions. Crystal data: 1, monoclinic, space group C2/m (No. 12), , , , β=93.601(4)°, , Z=2; 2, monoclinic, P2₁/c (No. 14), , , , β=99.926(4)°, , Z=4; 3, triclinic, space group P-1 (No. 2), , , , α=77.009(5)°, β=80.095(2)°, γ=82.334(3)°, , Z=2.     

Synthesis and structure of three manganese oxalates: MnC2O4·2H2O, [C4H8(NH2)2][Mn2(C2O4)3] and Mn2(C2O4)(OH)2

Three manganese oxalates have been hydrothermally synthesized, and their structures determined by single-crystal X-ray diffraction. MnC₂O₄·2H₂O (I) is orthorhombic, P2₁2₁2₁, , , , , Z=4, final R, R_w=0.0832, 0.1017 for 561 observed data (I>3σ(I)). The one-dimensional structure consists of chains of oxalate-bridged manganese centers. [C₄H₈(NH₂)₂][Mn₂(C₂O₄)₃] (II) is triclinic, , , , , α=81.489(2)°, β=81.045(2)°, γ=86.076(2)°, , Z=1, final R, R_w=0.0467, 0.0596 for 1773 observed data (I > 3σ (I)). The three-dimensional framework is constructed from seven coordinate manganese and oxalate anions. The material contains extra-framework diprotonated piperazine cations. Mn₂(C₂O₄)(OH)₂ (III) is monoclinic, P2₁/c, , , , β=91.10(3)°, , Z=1, final R₁, wR2=0.0710, 0.1378 for 268 observed data (I>2σ (I)). The structure is also three dimensional, with layers of MnO₆ octahedra pillared by oxalate anions. The hydroxide group is found bonded to three manganese centers resulting in a four coordinate oxygen.     

Synthesis and crystal structures of the layered uranyl tellurites A2[(UO2)3(TeO3)2O2] (A=K, Rb, Cs)

The reactions of UO₃ and TeO₃ with KCl, RbCl, or CsCl at 800 °C for 5 d yield single crystals of A₂[(UO₂)₃(TeO₃)₂O₂] (A=K (1), Rb (2), and Cs (3)). These compounds are isostructural with one another, and their structures consist of two-dimensional sheets arranged in a stair-like topology separated by alkali metal cations. These sheets are comprised of zigzagging uranium(VI) oxide chains bridged by corner-sharing trigonal pyramidal TeO₃²⁻ anions. The chains are composed of dimeric, edge-sharing, pentagonal bipyramidal UO₇ moieties joined by edge-sharing tetragonal bipyramidal UO₆ units. The lone-pair of electrons from the TeO₃ groups are oriented in opposite directions with respect to one another on each side of the sheets rendering each individual sheet non-polar. The alkali metal cations form contacts with nearby tellurite oxygen atoms as well as with oxygen atoms from the uranyl moieties. Crystallographic data (193 K, MoKα, ): 1, triclinic, space group , , , , α=101.852(1)°, β=102.974(1)°, γ=100.081(1)°, , Z=2, R(F)=2.70% for 98 parameters and 1697 reflections with I>2σ(I); 2, triclinic, space group , , , , α=105.590(2)°, β=101.760(2)°, γ=99.456(2)°, , Z=2, R(F)=2.36% for 98 parameters and 1817 reflections with I>2σ(I); 3, triclinic, space group , , , , α=109.301(1)°, β=100.573(1)°, γ=99.504(1)°, , Z=2, R(F)=2.61% for 98 parameters and 1965 reflections with I>2σ(I).     

Monitoring structural transformations in crystals. Part 4. Monitoring structural changes in crystals of pyridine analogs of chalcone during [2+2]-photodimerization and possibilities of the reaction in hydroxy derivatives

We studied the [2+2]-photodimerization in crystals of pyridine analogs and hydroxy derivatives of chalcone using the X-ray structure analysis. The mutual orientation of adjacent molecules in the crystals was analyzed in a quantitative way and the results were compared with data for known photoactive crystals undergoing the [2+2]-photodimerization. In the case of one pyridine analog, we processed the single-crystal-to-single-crystal photodimerization and determined the structure for the mixed crystal containing both the substrate and the product. We also explained a role of hydrogen bonds in the [2+2]-photodimerization in the case of the hydroxy derivatives of chalcone. C₅H₄N-CO-CHCH-C₆H₅: , , , β=91.318(10)°, monoclinic, . The irradiated crystal of the above analog: , , , β=91.870(10)°, monoclinic, . C₆H₅-CO-CHCH-C₅H₄N: , , , β=110.01(3)°, monoclinic, C2/c,Z=8. C₆H₅-CO-CHCH-C₆H₄(o-OH): , , , β=109.73(5)°, monoclinic, . C₆H₅-CO-CHCH-C₆H₄(p-OH): , , , orthorhombic, .     

Synthesis and characterization of two new open-framework zinc phosphites [M(C6N4H18)][Zn3(HPO3)4] (M=Ni, Co) with multi-directional intersecting 12-membered ring channels

Two new open-framework zinc phosphites, [M(C₆N₄H₁₈)][Zn₃(HPO₃)₄] (M=Ni, Co), have been prepared under hydrothermal conditions. Single-crystal X-ray diffraction analysis shows that [Ni(C₆N₄H₁₈)][Zn₃(HPO₃)₄] (1) and [Co(C₆N₄H₁₈)][Zn₃(HPO₃)₄] (2) are isostructural and both crystallize in the monoclinic space group C2/c with , , , β=109.83(3)°, Z=4, R₁=0.0408 (I>2σ(I)), and wR₂=0.1104 (all data) for 1, and , , , β=109.328(2)°, Z=4, R₁=0.0380 (I>2σ(I)), and wR₂=0.1093 (all data) for 2. The structures of 1 and 2 are built up from strictly alternating ZnO₄ tetrahedra and HPO₃ pseudo-pyramids linked through oxygen vertices to form the three-dimensional (3-D) open-frameworks with multi-directional intersecting 12-membered ring (12-MR) channels. The M(TETA) (M=Ni, Co) complexes self-assembled under hydrothermal system connect with the inorganic host via M-O-P linkages and interact with inorganic framework through weak H-bonds. The two compounds show intense photoluminescence upon photoexcitation at 235 nm.     

Self-assembly of silver polymers based on flexible isonicotinate ligand at different pH values: syntheses, structures and photoluminescent properties

Two interesting coordination polymers, [Ag₈(IN)₆(NO₃)₂] 1 and [Ag(IN)(HIN)]_1/2 [Ag(IN)] 2 (HIN=isonicotinic acid) have been synthesized hydrothermally at different pH values. 1 crystallizes in the triclinic space group P-1, with , , , α=75.87(3)°, β=80.87(3)°, γ=76.50(3)°, and Z=2. Compound 1 is the first example of a bilayer framework, in which both single layers are connected by the bond interactions (Ag-O) between Ag from two two-dimensional (2D) single layers generated by the A building block and O atoms from one-dimensional (1D) chain constructed by the B building block, in which coordination modes of IN were reported for the first time. 2 crystallizes in the monoclinic space group P2(1)/c, with , , , β=92.90(3)°, V=1185.0(4) and Z=4. Compound 2 exhibits a 2D plywood-like structure assembled by hydrogen bonds and weak Ag-O interactions.     

Syntheses and crystal structures of two new organically templated borates

Two new organically templated borates, [H₃N(C₆H₁₀)NH₃][B₄O₅(OH)₄] (1) and [H₃N(C₆H₁₀)NH₃][B₅O₈(OH)] (2) have been synthesized in the presence of trans-1,4-diaminocyclohexane acting as a structure-directing agent under mild solvothermal conditions. The structures were determined by single crystal X-ray diffraction and further characterized by FTIR, elemental analysis and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic system, space group C2/c (No. 15), , , , β=105.258(6)°, , Z=4. The structure contains supramolecular hydrogen-bonded network formed by isolated [B₄O₅(OH)₄]²⁻ polyanions. 2 is monoclinic, space group P2(1)/n (No. 14), , , , β=91.897(6)°, , Z=4. The structure consists of layers of 3,9-membered boron rings constructed from pentaborate anion groups [B₅O₈(OH)]²⁻. The adjacent borate layers are further linked with each other by hydrogen bond to form a 3D supramolecular network. It is the first example of layered borates templated by an organic amine.     

The disordered structures and low temperature dielectric relaxation properties of two misplaced-displacive cubic pyrochlores found in the Bi2O3-MO-Nb2O5 (M=Mg, Ni) systems

The disordered structures and low temperature dielectric relaxation properties of Bi_1.667Mg_0.70Nb_1.52O₇ (BMN) and Bi_1.67Ni_0.75Nb_1.50O₇ (BNN) misplaced-displacive cubic pyrochlores found in the Bi₂O₃-M^IIO-Nb₂O₅ (M=Mg, Ni) systems are reported. As for other recently reported Bi-pyrochlores, the metal ion vacancies are found to be confined to the pyrochlore A site. The B₂O₆ octahedral sub-structure is found to be fully occupied and well-ordered. Considerable displacive disorder, however, is found associated with the O′A₂ tetrahedral sub-structure in both cases. The A-site ions were displaced from Wyckoff position 16d (, , ) to 96 h (, , ) while the O′ oxygen was shifted from position 8b (, , ) to Wyckoff position 32e (, , ). The refined displacement magnitudes off the 16d and 8b sites for the A and O′ sites were 0.408 Å/0.423 Å and 0.350 Å/0.369 Å for BMN/BNN, respectively.