Ordered nanoporous plastics with hydrophilic pore surfaces were prepared by the degradative removal of polylactide from a self-organised, multi-component composite containing two block copolymers: polystyrene-polylactide and polystyrene-polyethylene oxide. The solid-state characterization of blends containing up to 12 wt.% polyethylene oxide was consistent with nanoscopic cylinders of mixed polyethylene oxide and polylactide hexagonally packed in a polystyrene matrix. Orientation of these materials through simple channel die processing resulted in good cylinder alignment. Subsequent methanolysis/hydrolysis of the polylactide component gave nanoporous polystyrene with polyethylene oxide coated pores. The resulting nanoporous materials were able to imbibe water, in contrast to nanoporous polystyrene with no polyethylene oxide component.

Template synthesis is a powerful method for the preparation of nanoscale materials with specific size and shape. We describe the template synthesis of polypyrrole nanowires and CdS nanoparticles within monolithic nanoporous polymer templates prepared from ordered block copolymer precursors. SAXS measurements confirmed retention of the host structure after growth of the nanomaterials within the pores of the template. SEM and TEM were used for direct visualization of the size and shape of the templated materials both in the monolith as well as after removal of the template through dissolution. The size of the templated nanomaterials matched that of the template pores and was modifiable by using templates containing different pore dimensions. For the case of CdS nanoparticles, WAXS was also used to verify particle size and crystal structure. In an effort to impregnate the nanoporous monoliths with CdS particles smaller than the pore dimensions of the template, a synthetic protocol utilizing a capping agent was employed. These particles were shown to exhibit a quantum size effect by DR-UV-Vis.

This report describes the synthesis and characterization of a 2D coordination network that directly incorporates an aniline-functionalized polyoxometalate (POM) cluster. By reacting a cobalt(II) salt of the POM cluster [Mo12O46(AsC6H4NH2)(4)](4-) with a bifunctional ligand, 4,4'-bipyridylethylene, a 2D coordination network was synthesized through a self-assembly process. The POM behaves as a non-coordinating anion and does not interfere with the coordination network other than occupying space. Thermal analysis reveals that the structure is stable to 350degreesC.

Polyoxometalate (POM) clusters derivatized with aniline groups exhibit distinct interactions with counterions and with each other. These interactions lead to the assembly of the clusters into chains and networks upon crystallization. Two cluster types were examined, [W(6)O(25)H(AsC(6)H(4)-4-NH(2))(2)](5-) and [Mo(12)O(46)(AsC(6)H(4)-4-NH(2))(4)](4-). The X-ray crystal structures were solved for the mixed salts containing [C(NH(2))(3)](+)/Na(+), Ag(+)/H(+), or Cu(2+)/H(+) as counterions. The X-ray crystal structures reveal that the POM clusters are linked together by hydrogen bonds or POM-metal ion-POM linkages. The roles of the counterions, solvents, and organic groups in the formation of specific crystalline architectures are discussed. Strongly interacting counterions form bonds to the oxo ligands of the POM and connect them into tetrameric units and/or into one-dimensional chains. The hydrogen bonding strength of the solvent influences the formation of hydrogen bonds between the aniline groups and oxo ligands of the cluster. The aniline groups played differing roles in the final structures: they were either nonbonding, bonded to a counterion, or involved in hydrogen bonding. Depending on the bonding interactions, the architecture of the cluster salts may be significantly altered.

A number of colloidal crystal templating methods have been developed to obtain macroporous inorganic solids with periodic pore structures (1-3). Interest in these materials has been driven to a large extent by proposed photonic applications. However, given their uniform pore structures, easily accessible surfaces, and efficient transport of guest molecules through the macropores, these materials are also promising candidates for catalyst supports. Macroporous silicates with hierarchical porosity are particularly interesting in this regard. They are obtained by dual templating methods, which produce structures with microporous or mesoporous walls surrounding the larger void spaces. This talk will discuss synthetic and structural aspects of macroporous silicates and other oxides, as well as the preparation of surface-modified macroporous supports which have been tested as catalysts in epoxidation reactions.

Three-dimensionally ordered macroporous (3DOM) silica materials functionalized with highly dispersed polyoxometalate clusters have been prepared via direct synthesis. Lacunary gamma -decatungstosilicate clusters were incorporated into the wall structures of macroporous silica by reaction of the clusters in acidic solution with tetraethoxysilane, with or without addition of the polyfunctional linking group 1,2-bis (triethoxysilyl) ethane, followed by condensation around polystyrene colloidal crystals. Removal of the polystyrene template by extraction with a tetrahydrofuran/acetone solution produced the porous hybrid materials. The products were characterized by IR, solid-state Si-29 and C-13 NMR, scanning electron microscopy (SEM:), transmission electron microscopy, X-ray energy-dispersive spectroscopy, and chemical analysis. The polyoxometalate clusters remained intact in the hybrid structures and were nearly molecularly dispersed throughout the walls of the 3DOM materials. High incorporation levels of cluster were obtained, with no bulk particles on the external surfaces. The materials were demonstrated to exhibit catalytic activity for the epoxidation of cyclooctene with an anhydrous H2O2/t-BuOH solution at room temperature.

New organic derivatives of "inverse-Keggin" polyoxometalate (POM) clusters, [Mo(12)O(46)(AsR)(4)](4-) (R = C(6)H(4)-4-COOH, C(6)H(3)-4-OH-3-NO(2), C(6)H(4)-4-OH), have been synthesized. Structures of the corresponding sodium or iron salts were elucidated by single-crystal X-ray diffraction and shown to be 3D structures connected through hydrogen bonds and/or O-Na-O linkages. Parameters which influence the final solid-state architecture, such as the crystallizing solvent, organic moiety, and counterions, have been examined. The hydrogen-bonding ability of the solvent affects the connectivity of the POM clusters through interactions with the organic group and the inorganic core. The organic groups influence the structure through hydrogen bonds to other organic groups, to neighboring clusters, and/or to solvent molecules. Hydrogen bonding between the organic groups and the solvent appears to inhibit some possible connectivity patterns, such as the hydrogen-bonded dimerization of carboxylic acid groups. Na(+) ions were found directly bonded to the cluster oxo ligands and provided linkages between clusters. Larger cations, such as transition metals, did not show this interaction, and other bonding methods dominated.

Transition-metal-substituted polyoxometalates (TMSP) of the type [MII(H2O)PW11O39]5- (M = Co, Zn) and [SiW9O37(CoII(H2O))3]10- have been chemically anchored to modified macroporous (400 nm pores), mesoporous (2.8 nm pores), and amorphous silica surfaces. The materials were characterized by solid-state 31P MAS NMR, UV-vis, FT-IR spectroscopy, and N2 adsorption experiments to verify cluster attachment and the structure of the TMSP on the support. On the basis of the spectroscopic evidence, clusters were attached datively to the surface, and the integrity of the [CoPW11] cluster was maintained for nonaqueous impregnation with TBA5[CoPW11]; partial degradation of the cluster occurred when it was impregnated from aqueous solution using the K5[CoPW11] salt. Both the amine surface groups and the cobalt centers in the clusters were found to be necessary to prevent cluster loss during washing or reaction processes. The catalytic activities of the supported TMSP clusters were tested by the epoxidation of cyclohexene to cyclohexene oxide in the presence of isobutyraldehyde. The percent conversion of the substrate and the amount of product formed per unit time were similar for [CoPW11] clusters on each of the three silica supports, but slightly lower than for purely homogeneous reactions. [SiW9Co3] clusters with three available cobalt centers exhibited higher catalytic activity with nearly identical performance on a silica support or in homogeneous solution.

Crystals of the title compound, (C 16 H 36 N) 4 [(p-NC-C 6 H 4 As) 4 Mo 12 O 46 ] or (C 16 H 36 N) 4 [{As(C 7 H 4 N)} 4 Mo 12 O 46 ], were synthesized by the reaction of p-cyanophenylarsonic acid and sodium molybdate at low pH. With nitrile groups pointed in tetrahedral directions, these new organically modified polyoxometalate clusters are potential building blocks in coordination networks.