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Three mixed-alkali metals uranyl silicates, Na 3 K 3 [(UO 2 ) 3 (Si 2 O 7 ) 2 ]·2H 2 O ( 1 ), Na 3 Rb 3 [(UO 2 ) 3 (Si 2 O 7 ) 2 ] ( 2 ), and Na 6 Rb 4 [(UO 2 ) 4 Si 12 O 33 ] ( 3 ), have been synthesized by high-temperature, high-pressure hydrothermal reactions at 550 °C and 1440 bar, and characterized by single-crystal X-ray diffraction, photoluminescence, and thermogravimetric analysis. Compound 1 and 2 are isostructural and contain layers of uranyl disilicate. The smaller cation, Na + , is located in the intralayer channels, whereas the larger cations, K + and Rb + , and water molecule are located in the interlayer region. The absence of lattice water in 2 can be understood according to the valence-matching principle. The structure is related to that of a previously reported mixed-valence uranium(V,VI) silicate. Compound 3 adopts a 3D framework structure and contains a unique unbranched dreier fourfold silicate chain with the structural formula {uB,4 1 ∞ }[ 3 Si 12 O 33 ] formed of Q 2 , Q 3 , and Q 4 Si. The connectivity of the Si atoms in the Si 12 O 33 18− anion can be interpreted on the basis of Zintl–Klemm concept. Crystal data for compound 1 : triclinic, P -1, a =5.7981(2) A, b =7.5875(3) A, c =12.8068(5) A, α =103.593(2)°, β =102.879(2)°, γ =90.064(2)°, V =533.00(3) A 3 , Z =1, R 1=0.0278; compound 2 : triclinic, P -1, a =5.7993(3) A, b =7.5745(3) A, c =12.9369(6) A, α =78.265(2)°, β =79.137(2)°, γ =89.936(2)°, V =546.02(4) A 3 , Z =1, R 1=0.0287; compound 3 : monoclinic, C 2/ m , a =23.748(1) A, b =7.3301(3) A, c =15.2556(7) A, β =129.116(2)°, V =2060.4(2) A 3 , Z =2, R 1=0.0304.

Two polymorphs of an organic–inorganic hybrid compound, Fe(2,2′-bpy)(HPO4)(H2PO4) (1 and 2) (2,2′-bpy=2,2′-bipyridine), have been synthesized by hydrothermal methods and structurally characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic susceptibility. Crystal data are as follows: Polymorph 1, monoclinic, space group P21/n (No. 14), a=10.904(2) A, b=6.423(1) A, c=19.314(3) A, β=101.161(3)°, and Z = 4 ; Polymorph 2, monoclinic, space group P21/c (No. 14), a=11.014(1) A, b=15.872(2) A, c=8.444(1) A, β=109.085(3)°, and Z = 4 . Polymorph 1 adopts a chain structure in which each iron atom is coordinated by two nitrogen atoms from 2,2′-bpy ligand and four phosphate oxygen atoms. These infinite chains are extended into a 3-D supramolecular array via π–π stacking interactions of the lateral 2,2′-bpy ligands. The structure of polymorph 2 consists of the same building units, namely FeO4N2 octahedron, HPO4 and H2PO4 tetrahedra, and 2,2′-bpy ligand, which are linked through their vertices forming an undulated sheetlike structure with 4,12 network. Adjacent layers are extended into a 3-D array via π–π stacking interactions of the aromatic groups. Magnetic susceptibility measurement results confirm that the iron atoms in both compounds are present in the +3 oxidation state.

Two new organic–inorganic hybrid compounds, [Ga(phen)(H1.5PO4)2]·H2O (1) and [Ga(phen)(HPO4)(H2PO4)]·1.5H2O (2) (phen=1,10-phenanthroline), have been synthesized by hydrothermal methods and structurally characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and solid-state NMR spectroscopy. Their structures consist of 1-D chains of strictly alternating GaO4N2 octahedra and phosphate tetrahedra. The phen ligands in both compounds bind in a bidentate fashion to the gallium atoms and the 1-D structures extend into 3-D supramolecular arrays via π–π stacking interactions of phen ligands and hydrogen bonds. 2H MAS NMR spectroscopy was applied to study the deuterated sample of 1 which contains very short hydrogen bonds with an O⋯O distance of 2.406(2) A. Crystal data for 1: monoclinic, space group C2/c (No. 15), a=11.077(1) A, b=21.496(2) A, c=7.9989(7) A, β=127.211(2)°, and Z=4. The crystal symmetry is the same for 2 as for 1 except a=27.555(2) A, b=6.3501(5) A, c=21.327(2) A, β=122.498(1)°, and Z=8.

Two fluorinated metal phosphates, M 2 F 2 (2,2′-bpy)(HPO 4 ) 2 (H 2 O) ( M =Fe, Ga), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic susceptibility. The two compounds are isostructural and crystallize in the triclinic space group p 1 , a=7.6595(8) A, b=10.101(1) A, c=11.260(1) A, α =107.555(2)°, β =105.174(2)°, γ =98.975(2)°, V=775.1(2) A 3 and Z =2 for the Fe compound, and a=7.5816(6) A, b=9.9943(7) A, c=11.1742(8) A, α =107.333(1)°, β =105.014(1)°, γ =99.261(1)° and V=754.2(2) A 3 for the Ga compound. They are the first fluorinated metal phosphates which incorporate 2,2′-bipyridine ligands. The structure consists of edge-sharing octahedral dimers with the composition Fe 2 F 4 (H 2 O) 2 O 4 and discrete FeN 2 O 4 octahedra, which are linked into two-dimensional sheets through corner-sharing phosphate tetrahedra. The 2,2′-bpy ligands bind in a bidentate fashion to the metal atoms and project into interlamellar region. The layers are extended into a three-dimensional supramolecular array via π – π stacking interactions of the 2,2′-bpy ligands. Magnetic susceptibility of the iron compound confirms the presence of Fe III .

Two new organically templated iron(II) phosphatooxalates, [( S )-C 5 H 14 N 2 ] [Fe 4 (C 2 O 4 ) 3 (HPO 4 ) 2 (H 2 O) 2 ] (1) and [( S )-C 5 H 14 N 2 ] [Fe 4 (C 2 O 4 ) 3 (HPO 4 ) 2 ] (2), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction and Mossbauer spectroscopy. Crystal data are as follows: compound 1, triclinic, P 1 (No. 1), a =7.6999(4) A, b =7.9542(4) A, c =9.8262(5) A, α =74.8444(7)°, β =81.7716(8)°, γ =85.4075(8)°, V =574.34(8) A 3 , Z =1, and R 1=0.0255; compound 2, monoclinic, P 2 1 (No. 4), a =7.5943(8) A, b =7.8172(8) A, c =18.318(2) A, β =99.111(2)°, V =1073.8(3) A 3 , Z =2, and R 1=0.0281. The structure of 1 consists of dimers of edge-sharing FeO 6 octahedra that are linked by phosphate and oxalate groups to generate a three-dimensional framework with intersecting tunnels parallel to the [100] and [010] directions. Diprotonated ( S )-2-methylpiperazinium cations are located at the intersections of these tunnels. Compound 1 crystallizes as a minor product when a racemic mixture of 2-methylpiperazine is used in the synthesis, and can be prepared as a major product with a small amount of 2 if optically pure ( S )-2-methylpiperzine is used. The structure of 2 is similar to that of 1 except that the coordination around the iron centers in the dimer are square pyramidal and octahedral. The two compounds are the first 3-dimensional phosphatooxalates containing a chiral amine.