Xiaoying Huang

Novel Single- and Double-Layer and Three-Dimensional Structures of Rare-Earth Metal Coordination Polymers: The Effect of Lanthanide Contraction and Acidity Control in Crystal Structure Formation

Lanthanide atom sizes (the lanthanide contraction) directly control the type of structure formed by the coordination of a single multidentate ligand, 3,5-pyrazoledicarboxylic acid (H(3)pdc). Single-layer, double-layer ([Eu(2)(Hpdc)(3)(H(2)O)(6)], see picture), and three-dimensional networks were found. Control of the reaction pH plays a key role in the structure formation in this system.

A Reversible Structural Interconversion Involving [M(H2pdc)2(H2O)2]⋅2 H2O (M=Mn, Fe, Co, Ni, Zn, H3pdc=3,5‐pyrazoledicarboxylic acid) and the Role of A Reactive Intermediate [Co(H2pdc)2]

A new type of hydrogen bonded networks [M(H2pdc)2(H2O)2] . 2H2O [M = Mn (1), Fe (2), Co (3), Ni (4), Zn (5); H3pdc = 3,5-pyrazoledicarboxylic acid] have been synthesized via hydrothermal reactions and their structures have been characterized. Upon a cooling-heating cycle, these compounds undergo a reversible structural interconversion process via hydration-dehydration: [chemical equation: see text]. The process is associated with distinct color changes. The dehydrated [M(H2pdc)2] (M = Mn, Fe, Co, Ni, and Zn) are amorphous and highly reactive. Further chemical reactions of these reactive intermediates show that they may act as effective precursors towards assembly of new supramolecular compounds that may otherwise be inaccessible by other synthetic routes. An interesting structure containing an open-box molecule [Co4(Hpdc)4(py)12] . 4py . 2H2O . 2CH3OH (6) (py=pyridine) has been isolated by using dehydrated [Co(H2pdc)2] as the precursor, and its crystal structure has been analyzed. Crystal data for 1-6: monoclinic, space group P2(1/c) and Z = 2 with a = 10.186(2), b = 12.473(2), c = 6.831(1) A, beta = 108.80(3) degrees (1); a = 9.896(2), b = 12.402(2), c = 6.810(1) A, beta = 108.15(3) degrees (2); a = 9.981(2), b = 12.426(2), c = 6.807(1) A, beta = 108.23(3) degrees (3); a = 9.896(2), b = 12.402(2), c = 6.810(1) A, beta = 108.15(3) degrees (4); a = 10.001(2), b = 12.430(2), c = 6.834(1) A, beta = 108.32(3) degrees (5); a = 9.9617(1), b=18.5080(2), c = 28.4786(3) A, beta = 93.076(1) degrees (6).

Controlled Synthesis and Magnetic Properties of 2D and 3D Iron Azide Networks

Controlled synthesis of transition metal complexes with mixed ligands has led to two new compounds with the same empirical formula [Fe(N3)2(4,4-bpy)] (4,4-bpy=4,4- bipyridine). The compound 2D-[Fe(N3)2(4,4-bpy)] (I) contains end-on (EO) bridging azido ligands. It crystallizes in the orthorhombic crystal system, space group Cmmm (No. 65): a=11.444(2) A, b=15.181(3) A, c=3.458(1) A, V=600.8(2) A(3), and Z=2. The compound 3D-[Fe(N3)2(4,4-bpy)] (II) contains end-to-end (EE) azido bridges. It belongs to the tetragonal crystal system, space group P4(1)2(1)2 (No. 92): a=8.132(1) A, b=8.132(1) A, c=16.708(3) A, V=1104.9(5) A(3), and Z=4. Crystals of I and II have been grown by the diffusion method. Phase-pure samples of both compounds have been obtained by means of an optimal solution synthesis. Spontaneous long-range magnetic ordering was found in both I and II, with I being a metamagnet, and II being a ferromagnet. For I, in the low-field region, multiple transitions at TN1=20 K and TN2=5 K were observed, and these indicated the existence of Fe moment reorientation. Heat capacity measurements on II confirmed ferromagnetic transition at TC=20 K.

\rm{^{2}_{\infty }}

that many favorable properties of each individual component are brought into the hybrid structure by incorporating two distinctly different components into a single crystal lattice. Integration and combination of exceptional transport properties and structural/thermal stability from the inorganic component and superb flexibility and processibility from the organic component can be expected. Additionally, the blending of the inorganic and organic modules in these crystalline hybrid structures takes place at the atomic level and through chemical bonds, and thus is free of the interface issues that are inevitably present in conventional hybrid composite materials. Furthermore, the formation of such hybrid crystals almost always leads to unique and remarkable new features that are not possible for the individual constituents. Some notable examples include organic–inorganic perovskite-like structures and related materials, [1–4] hybrid metal oxides, [5, 6] and semiconductors composed of zinc blende and wurtzite frameworks. [7–9] The II/VI based hybrid semiconductor crystal structures

[Fe(N3)2(4,4′‐bpy)] and

Single crystals of a zirconium-glycine compound have been first grown in aqueous solution via an excess acid and extra stabilizer approach. The crystal structure [Zr 6(OH (-)) 8(H 2O) 8(HGly) 4(Gly (-)) 4].(SO 4 (2-)) 6.14H 2O ( CP-1) has been characterized by single-crystal X-ray diffraction. The structure revealed that it is composed of hexa-zirconium octahedral clusters coordinated by eight carboxylic acid groups of glycine. The charge assignment is also consistent with the electronic structure calculations, and the computational result reveals that the Zr 6 core should have no skeleton electrons.

\rm{^{3}_{\infty }}

Use of an ionic liquid [bmim][BF4] (bmim = 1-butyl-3-methylimidazolium) as solvent has resulted in the first extended coordination structure, the two-dimensional network [Cu(bpp)]BF4 [bpp = 1,3-bis(4-pyridyl)propane], produced via a solvothermal route.

[Fe(N3)2(4,4′‐bpy)]

The solid compound formulated as [Cu(4,7-phen)-(H2O)3](ClO4)2·(4,7-phen)2 n(phen=phenanthroline) has been shown by single-crystal structural analysis to be a three-dimensional network with hexagonal channels, constructed of one-dimensional S-shaped [Cu(4,7-phen)(H2O)3]n2n+ cationic chains and solvated 4,7-phen molecules, linked through extensive hydrogen bonds and π–π interactions.

Flexible hybrid semiconductors with low thermal conductivity: The role of organic diamines

Two octadecanuclear clusters [Cu12Ln6(µ3-OH)24(O2CCH2CH2NC5H5)12(H2O)16(µ12-ClO4)][ClO4]17·16H2O (LnIII= GdIII or SmIII) have been synthesized and characterized by X-ray structural analysis. The clusters are isostructural, crystallizing in the triclinic space group P with Z= 1. In each structure six LnIII are positioned at the vertices of an octahedron with twelve CuII at the midpoints of the edges of the octahedron. The 24 OH– groups act as µ3 bridges each ligating one LnIII and two CuII. The octahedron encapsulates an unusual µ12-ClO4– anion of which each oxygen atom co-ordinates to three CuII at the axial positions. Ten of the C5H5N+CH2CH2CO2– ligands act in the µ-carboxylato-O,O′ mode, while the other two act in the carboxylato-O,O′ mode each chelating a LnIII, resulting in different co-ordination environments for the CuII and LnIII.

Synthesis and Structural Determination of a Hexanuclear Zirconium Glycine Compound Formed in Aqueous Solution

A novel coordination polymer of mixed-valence copper(I,II) with 4,4-bipyridine and in situ oxidized isophthalate, [Cu2(ipO)(4,4-bpy)] (ipOH = 2-hydroxyisophthalate), was hydrothermally synthesized and crystallographically characterized to be a laminated structure via weak copper(II)--oxygen interactions.

[Cu(I)(bpp)]BF4: the first extended coordination network prepared solvothermally in an ionic liquid solvent.

Reaction of an aqueous solution of Na2bpdc n(H2bpdc = biphenyldicarboxylic acid) with an organic solution of nCo(NO3)2via a diffusion route leads to a npillared three-dimensional structure in which the heterometallic nsodium(I)–cobalt(II) trilayers are connected by ncarboxylate groups of the pillared ligand bpdc2−.