Although zeolites and related materials combine nanoporosity with high thermal stability, they are difficult to modify or derivatize in a systematic way. A highly porous metal coordination polymer [Cu3(TMA)2(H2O)3]n (where TMA is benzene-1,3,5-tricarboxylate) was formed in 80 percent yield. It has interconnected [Cu2(O2CR)4] units (where R is an aromatic ring), which create a three-dimensional system of channels with a pore size of 1 nanometer and an accessible porosity of about 40 percent in the solid. Unlike zeolites, the channel linings can be chemically functionalized; for example, the aqua ligands can be replaced by pyridines. Thermal gravimetric analysis and high-temperature single-crystal diffractometry indicate that the framework is stable up to 240 degreesC.

A series of ten 2,3,4,5-tetraphenylsiloles with different 1,1-substituents [XYSi(CPh)4] were prepared, and three of these, i.e., 1,1,2,3,4,5-hexaphenylsilole [X = Y = Ph (3)], 1-ethynyl-1,2,3,4,5-pentaphenylsilole [X = Ph, Y = C⋮CH (15)], and 1,1-bis(phenylethynyl)-2,3,4,5-tetraphenylsilole [X = Y = C⋮CPh (18)], were characterized crystallographically. The ground- and excited-states of the siloles were influenced by the inductive effect of the 1,1-substituents:  with an increase in their electronegativity, the absorption and emission spectra of the siloles bathochromically shifted. A simple and reliable TLC-based method was developed for measurement of the solid-state luminescence spectra of the siloles. When molecularly dissolved in common solvents at room temperature, all the siloles were practically nonemissive (“off”). When poor solvents were added, the silole molecules clustered into nanoaggregates, which turned the emission “on” and boosted the photoluminescence quantum yields by up to 2 orders of magnitude (aggregation-induced emission). The silole emission could also be greatly enhanced by increasing the viscosity and decreasing the temperature of the silole solutions. The solution thickening and cooling experiments suggest that the aggregation-induced emission is caused by the restricted intramolecular rotations of the peripheral aromatic rings upon the axes of the single bonds linked to the central silole cores.

Metal coordination polymer chemistry is a growing field, its exploration driven in part by the search for novel magnetic materials 1,2 as well as for new microporous phases 3 and catalysts 4 which are complementary to zeolites. Recently, we reported the solvothermal synthesis of a highly porous yet stable coordination polymer from copper ions and trimesic acid [Cu 3 {1,3,5- 5 Central to the stability of 1 is the structural rigidity of its [Cu 2 (µ-O 2 CR) 4 L 2 ] dimer units (Figure 1). A recent report by Japanese workers of a related sorption polymer [Cu-{1,4-C 6 H 4 (COO) 2 }(H 2 O) x ] n , 6 prompted us to explore the solvothermal chemistry of the copper terephthalate system.Herein we report that under solvothermal or hydrothermal conditions, reaction of copper(II) nitrate, terephthalic acid, and 4,4′-bipyridine 7 results in the formation of an air-stable, openframework coordination polymer with mixed-valence [Cu 2 ] 3+ dimer subunits, [Cu 4 {1,4-C 6 H 4 (COO) 2 } 3 (4,4′-bipy) 2 ] n , 2. We believe that the polymer represents the trapping through "supramolecular precipitation" of the unstable Cu(I)-Cu(II) dimers which are produced under the reducing conditions prevalent in the reaction media at high temperatures.Compound 2 is formed phase-pure as small dark-blue blocks of ∼100 µm dimension in ∼65% yield from a solvothermal reaction (180 °C, 1 day) of [Cu(NO 3 ) 2 ]‚H 2 O, [1,4-C 6 H 4 (COOH) 2 ] and [4,4′-bipy] of 1:1:1 ratio in 50% aqueous ethanol. Larger crystal specimens up to 1 mm are formed, although in much reduced yield ( ∼20% of the isolated solids) from a parallel hydrothermal reaction with copper sulfate. The dark coloration suggested a rather novel structure for 2 which was confirmed by single-crystal diffraction. 8 Rather than the expected "paddle-wheel" arrangement of four bridging carboxylates, found in 1, an open-framework polymer containing dimeric [Cu 2 (µ-O 2 CR) 3 L 2 ] units with only three carboxylate bridges is found in compound 2. (Figure 2) Once the framework atoms had been refined, difference Fourier maps revealed no peaks of chemical significance, residual electron density maxima and minima were +0.92/-0.97 e Å -3 , both less than 1 Å from Cu. The necessity to charge balance the ligands in 2, indicate that the metals have a mixed Cu(I)-Cu(II) formulation. Other structural evidence for this comes from the unusually short Cu-Cu separation of 2.442(1) Å. This is consistent with the majority of [Cu 2 ] 3+ complexes determined previously, 9-11 which also have short "bonds". 12 Furthermore the bond valence sums indicate equivalence of the Cu centers and a delocalized 1.5+ "oxidation state" for each site.

Pyridine-3,5-dicarboxylic acid has been studied by single-crystal neutron diffraction at 15 and 296 K. Pyridine-3,5-dicarboxylic acid, in which the carboxylic acid protons have been replaced by deuterons, has also been studied at 15, 150 and 296 K. The protonated structure contains a short N...H...O hydrogen bond [N...O 2.523 (2) Angstrom at 15 K]. Temperature-dependent proton migration occurs where the N--H distance in the hydrogen bond changes from 1.213 (4) Angstrom at 15 K to 1.308 (6) Angstrom at 300 K. In the deuterated structure the overall hydrogen-bond length increased [N...O 2.538 (3) Angstrom at 15 K] and the magnitude of the migration increased so that the N--D distance changes from 1.151 (3) Angstrom at 15 K to 1.457 (4) Angstrom at 300 K.

The 1:2 adduct of benzene-1,2,4,5-tetracarboxylic acid and 4,4'-bipyridyl at 100 K has been studied by single-crystal neutron diffraction at 20, 200 and 296 K. The structure contains two short, strong N...O hydrogen bonds: one O-H...N hydrogen bond [O...N 2.6104 (17) A at 20 K] and one short N-H...O hydrogen bond [N...O 2.5220 (17) A at 20 K]. The N-H distance in the N-H...O hydrogen bond changes from 1.207 (3) A at 20 K to 1.302 (4) A at 296 K and the N...O distance increases to 2.5315 (16) A at 296 K. At 200 K the H atom lies in an intermediate position 1.251 (6) A from the N atom with an N...O separation of 2.520 (4) A. The O-H...N hydrogen bond, on the other hand, does not change with temperature.

Hollow spheres of mesostructured lead titanate, denoted as PTM-1, have been prepared via a combined oil-in-water emulsion mediated and neutral amine supermolecular templated route. The variety of reaction temperatures and KOH concentrations indicates hollow spheres can be formed under a very critical condition. The structure and composition of the as-synthesized PTM-1 have been determined by powder X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), CHN (carbon-hydrogen-nitrogen) elemental analysis, and thermal analysis. Chemical extraction of organic templates by a cosolvent of weak acid and alcohol has resulted in the formation of a new mesoporous material of non-silica oxide with high porosity.

Treatment of [Ti(O-i-Pr)(2)Cl(2)] with NaL(OEt) (L(OEt)(-) = [CpCo[P(O)(OEt)(2)](3)](-), Cp = eta(5)-C(5)H(5)) afforded [L(OEt)Ti(O-i-Pr)(2)Cl] that reacted with HCl in ether to give [L(OEt)TiCl(3)] (1). The average Ti-O and Ti-Cl distances in 1 are 1.975 and 2.293 A, respectively. Reaction of titanyl sulfate with NaL(OEt) in water followed by addition of HBF(4) afforded [L(OEt)TiF(3)] (2), the Ti-O and Ti-F distances of which are 2.020(2) and 1.792(2) A, respectively. The Zr(IV) analogue [L(OEt)ZrF(3)] (3) was prepared similarly from zirconyl nitrate, NaL(Oet), and HBF(4) in water. The Zr-O and average Zr-F distances in 3 are 2.139(2) and 1.938(2) A, respectively. Treatment of 1 with tetrachlorocatechol (H(2)Cl(4)cat) afforded [L(OEt)Ti(Cl(4)cat)Cl] (4). The average Ti-O(P), Ti-O(C), and Ti-Cl distances in 4 are 1.972, 1.926, and 2.334 A, respectively. Hydrolysis of 4 in the presence of Et(3)N yielded the mu-oxo dimer [(L(OEt))(2)Ti(2)(Cl(4)cat)(2)(mu-O)] (5). The average Ti-O(P), Ti-O(C), and Ti-O(Ti) distances in 5 are 2.027, 1.926, and 1.7977(9) A. Treatment of 1 with 1,1'-binaphthol (BINOLH(2)) in the presence of Et(3)N afforded [(L(OEt))(2)Ti(2)(mu-O)(2)(mu-BINOL)] x 2BINOLH(2) (6.2BINOLH(2)). Complex 1 is capable of catalyzing ring opening of epoxides with Me(3)SiN(3) under solvent-free conditions presumably via a Ti-azide intermediate.

Water soluble and stable: The treatment of zirconyl nitrate with the Kläui tripodal oxygen ligand in dilute nitric acid gives a water‐soluble tetranuclear hydroxo‐bridged ZrIV compound (depicted, C gray; O red; P purple; Co blue; Zr green), which reacts with a phosphodiester to give a ZrIV phosphate cubane cluster.