To systematically explore the higher-dimensional network structures with mixed connectivity, a series of two-dimensional (2D) and three-dimensional (3D) metal-organic frameworks (MOFs) with unusual (3,6)-connected net topologies are presented. These crystalline materials include [{[Mn(btza)2(H2O)2].2 H2O}n] (1), [{[Zn(btza)2(H2O)2].2 H2O}n] (2), [{[Cu(btza)2].H2O}n] (3), and [{[Cd(btza)2].3 H2O}n] (4), which have been successfully assembled through a predesigned three-connected organic component bis(1,2,4-triazol-1-yl)acetate (btza) with a variety of octahedral metal cores based on the modular synthetic methodology. The topological paradigms shown in this work cover the 2D CdCl2, 3D (4(2).6)2(4(4).6(2).8(7).10(2)), and pyrite (pyr) types. That is, when properly treated with the familiar first-row divalent metal ions, btza may perfectly furnish the coordination spheres for effective connectivity to result in diverse (3,6)-connected nets. Beyond this, a detailed analysis of network topology for all known 3D (3,6)-connected frameworks in both inorganic and inorganic-organic hybrid materials is described. Specific network connectivity of these MOFs indicates that the metal centers represent the most significant and alterable factor in structural assembly, although they show reliable and similar geometries. In this context, the combination of the distinct d10 AgI ion with btza in different solvents affords two isomorphous MOFs [{[Ag(btza)].glycol}n] (5) and [{[Ag(btza)]CH3OH}n] (6) with a binodal 4-connected 3D SrAl2 (sra) topology. The network structures of MOFs 1-3 and 5 turn out to be more complicated and interesting if one considers the hydrogen bonding between the host coordination frameworks and the intercalated solvent molecules. Furthermore, the role of the included solvents in the generation and stabilization of MOFs 1-6 is also investigated.

A series of microporous lanthanide metal-organic frameworks, Tb3(BDC)(4.5)(DMF)2(H2O)3.(DMF)(H2O) (1) and Ln3(BDC)(4.5)(DMF)2(H2O)3.(DMF)(C2H5OH)(0.5)(H2O)(0.5) [Ln = Dy (2), Ho (3), Er (4)], have been synthesized by the reaction of the lanthanide metal ion (Ln3+) with 1,4-benzenedicarboxylic acid and triethylenetetramine in a mixed solution of N,N'-dimethylformamide (DMF), water, and C(2)H(5)OH. X-ray diffraction analyses reveal that they are extremely similar in structure and crystallized in triclinic space group P. An edge-sharing metallic dimer and 4 metallic monomers assemble with 18 carboxylate groups to form discrete inorganic rod-shaped building units [Ln6(CO2)18], which link to each other through phenyl groups to lead to three-dimensional open frameworks with approximately 4 x 6 A rhombic channels along the [0,-1,1] direction. A water sorption isotherm proves that guest molecules in the framework of complex 1 can be removed to create permanent microporosity and about four water molecules per formula unit can be adsorbed into the micropores. These complexes exhibit blue fluorescence, and complex 1 shows a Tb3+ characteristic emission in the range of 450-650 nm.

A series of new metal-organic polymeric complexes, [[Co(bpt)(Htma)(H2O)3].2.25H2O]n (1), [Co(bpt)(Htma)(H2O)]n (2), [Ni(bpt)(Htma)(H2O)]n (3), [Zn(bpt)2(H2tma)2].6H2O (4), [[Cd(bpt)(Htma)(H2O)].(C2H5OH)(H2O)1.5]n (5), and [[Cd(bpt)(Htma)(H2O)2].5.5H2O]n (6), was prepared from solution reactions of 4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole (bpt) and trimesic acid (H3tma) with different metal salts under diverse conditions. All these compounds were structurally determined by X-ray single-crystal diffraction, and the bulk new materials were further identified by X-ray powder diffraction. Complexes 1 and 6 show 1-D zigzag or linear Htma-bridged polymeric chains, with the terminal bpt ligands as pendants, which are extended to 2-D hydrogen-bonded arrays with 4.8(2) or (6,3) network topology. Coordination polymers 2 and 3, in which the 2-D corrugated metal-organic frameworks make the interdigitated 3-D packing, are isostructural. Complex 4 has a mononuclear structure, and its subunits are hydrogen-bonded to each other to give a 2-D grid-like net. For complex 5, the Cd(II) centers are linked by bpt/Htma ligands to form a 2-D (4,4) coordination layer, and these layers are interdigitated in pairs. Notably, secondary noncovalent forces, such as hydrogen bonds, play an important role in extending and stabilizing these structural topologies. Interestingly, distinct products are obtained for Co(II) (1 and 2) and Cd(II) (5 and 6) under ambient or hydrothermal conditions; however, for Ni(II) and Zn(II), single products, 3 and 4, are generated. The thermal stabilities of 1-6 were studied by thermogravimetric analysis of mass loss. The desorption/adsorption properties of the porous material 5 are also discussed. Solid-state luminescent spectra of the Zn(II) and Cd(II) complexes, 4-6, indicate intense fluorescent emissions at ca. 380 nm.

Landscape Architecture (E.J.S.), University ofMinnesota, St. Paul, Minnesota 55108 MATERIALS AND METHODSThis study was undertaken to quantify the effect of aluminum and calcium on membrane permeability. The influence of Ca2" (0.2-3.7 millimolar) and Al' (0-3.7 millimolar) on the permeability of root cortical cells of Quercus rubra was measured using three nonelectrolytes (urea, methyl urea, and ethyl urea) Aluminum, as Al3", can interfere with physiological processes and be toxic to plant cells (1,5,(8)(9)(10)15). Plant cell membranes may be a site of primary lesions from Al3" (1,10). Hofler (10) and Bohm-Tuchy (1) showed that Al3" changed the attachment of the plasmalemma to the cell wall causing the membrane to assume a convex shape on plasmolysis. Bohm-Tuchy (1) also suggested that Al3" solidifies the outer region of the protoplasmic layer. Vierstra and Haug (19) using EPR spectroscopy showed that Al3" decreased membrane fluidity in isolated membranes and intact cells of a thermophilic bacterium.Ca2" is another ion well known to influence the integrity and functions of membranes (13,14). Recent work (9) shows negative interactions between Al3+ and Ca2" with regard to calmodulin activity and other physiologic processes (5, 15).The capacity of Al3" and other cations to alter the biochemical and biophysical properties of both the lipid and protein portions of membranes is well reviewed by Haug (8). Changes in the lipid portion of the membrane could result in an alteration of permeability to nonelectrolytes and to water. A major objective of this study was to measure how Al3+ altered the combined permeability of the plasma and vacuolar membranes in the root cortex cells of red oak. A related objective was to determine whether the effects of Al3" vary with the concentration of Ca2". Permeability Measurements. The solute permeability of the plasma membrane and tonoplast in series was measured by the techniques described by Stadelmann (17). Immediately after sectioning, the tissue was sequentially exposed to increasing concentrations of sucrose. The sections were in 0.1 M sucrose for 1 h, in 0.2, 0.3, and 0.4 M for 30 min each, and 0.5 M for 1 h. At this osmolarity (0.59 osm) all intact cells were plasmolyzed. The tissue sections in 0.5 M sucrose were transferred in a droplet of the same solution into a perfusion chamber (21). In the chamber, the sucrose solution was replaced with isotonic solutions or urea family permeators (urea, methyl urea, or ethyl urea

A red-emitting layer constructed from {Eu2Na(CH3COO)2} chains and 4,4′-(pyridine-2,6-diyl)dibenzolate linkers exhibits luminescent discriminations for three nitrofuran antibiotics and toxic Cr2O72− and MnO4− anions.

The peroxidase-like activity of graphitic carbon nitride (g-C3N4) is dramatically increased by a small cobalt doping. The cobalt-doped g-C3N4 was used for wastewater treatment, exhibiting much higher degradation rate than that of pure g-C3N4.

The construction of two types of coordination polymers with closely related 4-connected topologies [PtS and lvt (4(2).8(4))] were achieved based on a well-designed bent dipyrazine linker, and the topological differences only result from the stereochemistry of silver(I) coordination sphere with the same coordination donors. Selective anion-exchange functions of the series of PtS-type coordination networks containing different counter anions (from small BF4- to very large SbF6-) were identified.

A novel 3D lead(II) metal-organic framework {Pb 4 (Bdc) 3 -(m 4 -O)(H 2 O)} n (1) (H 2 Bdc = isophthalic acid) with octanuclear [Pb 8 (Bdc) 6 (m 4 -O) 2 (H 2 O) 2 ] as secondary building units (SBUs) has been obtained and fully characterized by single crystal X-ray diffraction, IR, elemental analysis, TG-DTA and fluorescent spectra. XRD results indicate octanuclear lead(II) SBU contains two inversely related [Pb 4 (m 4 -O)] cores and is extended topologically into an infinite eight-connected bcu-type network via twelve Bdc ligands linking eight neighboring SBUs. At room temperature, 1 in the solid-state exhibits strong emission peak at 424 nm originated from the LMCT between delocalized p bonds of Bdc carboxylate groups and p orbitals of lead(II) centers.