Functionalisation of alkali-resistant nanoporous glass via Au nanoparticle decoration using alkaline impregnation: catalytic activity for CO removal.

The concerted use of nano-metal particles with catalytic functions and nanoporous materials holds promise for effective air purification and gas sensing; however, only a few studies have used porous glasses as supports for Au nanoparticles. Furthermore, Au/nanoporous glasses with activities comparable to that of Au/TiO2, which is a typical Au catalyst, have not been reported to date. This study demonstrates that a nanoporous glass, which is highly acid- and alkali-resistant and chemically stable, can be decorated with Au nanoparticles using an alkali impregnation method. The resulting composite exhibits high catalytic activity in CO oxidation. The catalysts reported herein are as active as Au/TiO2 catalysts per active site. Further optimisation of the pore properties of the glass and sizes of the Au nanoparticles is expected to result in excellent catalytic systems for CO removal and sensing.

Photogeneration of Microporous Amorphous Coordination Polymers from Organometallic Ionic Liquids.

Ruthenium-containing organometallic ionic liquids with the B(CN)4 anion were developed that generate microporous amorphous coordination polymers upon UV irradiation. UV light irradiation of [Ru(C5 H5 )(C6 H5 R)][B(CN)4 ] (R=butyl, ethyl, octyl) quantitatively generated a yellow powder of a coordination polymer with the formula [Ru(C5 H5 ){B(CN)4 }]n . In this reaction, the arene ligand is eliminated by UV irradiation and coordination polymer is formed by coordination of the cyano groups of the anion to the Ru ion. The photogenerated solids exhibited nitrogen absorption properties due to their microporous structure. This paper proposes a method to fabricate functional coordination polymers by photoirradiation of liquids.

Multifunctional Ionic Liquids from Rhodium(I) Isocyanide Complexes: Thermochromic, Fluorescence, and Chemochromic Properties Based on Rh-Rh Interaction and Oxidative Addition.

Square-planar rhodium(I) isocyanide complexes exhibit unique chemical reactivities such as the formation of Rh-Rh bonds and oxidative addition. This paper details the syntheses and properties of multifunctional ionic liquids containing RhI isocyanide complexes [Rh(nBuNC)4 ]X (X=Tf2 N (=N(SO2 CF3 )2- ), Nf2 N (=N(SO2 C4 F9 )2- ), FSA (=N(SO2 F)2- ), CF3 BF3- ). Salts with Tf2 N and Nf2 N were liquids, whereas those with FSA and CF3 BF3 were solids at room temperature. The salts exhibited thermochromism in the liquid state, changing from orange at high temperatures to blue-purple at lower temperatures. This is based on the equilibrium between monomer, dimer, and other oligomers associated with Rh-Rh bond formation. The salts also exhibited fluorescence. Exposure of the Tf2 N salt to methyl iodide vapor produced ionic liquid mixtures [Rh(nBuNC)4 ]x [Rh(nBuNC)4 IMe](1-x) [Tf2 N], concomitant with a color change from purple to red, orange, and yellow, extending the thermochromic color range. The reaction of the Tf2 N salt and iodine produced mononuclear and polynuclear iodine adducts. Thus, these liquids exhibit thermochromism, fluorescence, vapochromism, chemical reactivities, and characteristic properties of ionic liquids.

Paramagnetic ionic plastic crystals containing the octamethylferrocenium cation: counteranion dependence of phase transitions and crystal structures.

In recent years, ionic plastic crystals have attracted much attention. Many metallocenium salts exhibit plastic phases, but factors affecting their phase transitions are yet to be elucidated. To investigate these factors, we synthesized octamethylferrocenium salts with various counteranions [Fe(C5Me4H)2]X ([1]X; X- = B(CN)4-, C(CN)3-, N(CN)2-, FSA (= (SO2F)2N-), FeCl4-, GaCl4- and CPFSA (= CF2(SO2CF2)2N-)) and elucidated their crystal structures and phase behavior. Correlations between the crystal structures and phase sequences, and the shapes and volumes of the anions are discussed. Except for [1][CPFSA], these salts exhibit phase transitions to plastic phases at or above room temperature (TC = 298-386 K), and the plastic phases exhibit either NaCl- or anti-NiAs-type structures. X-ray crystal structure analyses of these salts at 100 K revealed that they have structures in which cations and anions are alternately arranged, with the exception of [1][CPFSA]. [1][CPFSA] exhibits a structure in which anions and cations are separately stacked to form columns. [1][N(CN)2] exhibits a polar crystal structure that undergoes a monotropic phase transition to a centrosymmetric structure. The magnetic susceptibilities of room-temperature plastic crystals [1][GaCl4] and [1][FeCl4] were investigated; the latter exhibits a small ferromagnetic interaction at low temperatures.

Coordination abilities of polycyano anions in the solid state: coordination geometries and d-d transition energies of mixed-ligand solvatochromic copper(ii) complexes with B(CN)4, C(CN)3, and N(CN)2 anions.

B(CN)4-, C(CN)3-, and N(CN)2- are highly versatile polycyano anions that produce various functional compounds. To investigate the coordination abilities of these anions in the solid state quantitatively, we synthesized mixed-ligand Cu(ii) complexes: [Cu(R-acac)(tmen)X] (X = polycyano anion, R-acac = acetylacetonate or butyl-acetylacetonate, tmen = tetramethylethylenediamine). The coordination abilities of the anions, increasing in the order B(CN)4- < C(CN)3- < N(CN)2-, result in a decrease in the d-d transition energies of the complexes and the shortening of the axial coordination distance. The influence of crystal packing on the coordination geometries and d-d transition energies of the complexes was also demonstrated. The donor numbers of the anions were determined from the d-d transition energies in solution.

Effect of substituents and anions on the phase behavior of Ru(ii) sandwich complexes: exploring the boundaries between ionic liquids and ionic plastic crystals.

We recently developed ionic liquids containing cationic sandwich complexes. However, salts of the sandwich complexes often exhibit ionic plastic phases with high melting points. To explore the boundaries between ionic liquids and plastic crystals of sandwich salts, we investigated, in detail, the phase behavior of ruthenium complexes [Ru(C5H5)(C6H5R)][X] ([C0][X]: R = H, [C1][X]: R = Me, [C2][X]: R = Et, [C4][X]: R = Bu). Among salts containing the anions PF6-, FSA-, and B(CN)4-, [C0][X] and [C1][X] are solids that exhibit plastic phases at or above room temperature, whereas [C2][X] and [C4][X] are mostly ionic liquids. Salts containing the C(CN)3- anion exhibited lower melting points than the other salts. X-ray crystallography reveals that the cations and anions in most of these salts are arranged alternately in the solid state. However, in the case of [C0][C(CN)3], the cations and anions are stacked independently, thereby providing weaker cation-anion interactions that account for the relatively low melting point of this salt.

Structure of Saccharomyces cerevisiae mitochondrial Qri7 in complex with AMP.

N(6)-Threonylcarbamoyladenosine (t(6)A) is a modified tRNA base required for accuracy in translation. Qri7 is localized in yeast mitochondria and is involved in t(6)A biosynthesis. In t(6)A biosynthesis, threonylcarbamoyl-adenylate (TCA) is synthesized from threonine, bicarbonate and ATP, and the threonyl-carbamoyl group is transferred to adenine 37 of tRNA by Qri7. Qri7 alone is sufficient to catalyze the second step of the reaction, whereas the Qri7 homologues YgjD (in bacteria) and Kae1 (in archaea and eukaryotes) function as parts of multi-protein complexes. In this study, the crystal structure of Qri7 complexed with AMP (a part of TCA) has been determined at 2.94 Šresolution in a new crystal form. The manner of AMP recognition is similar, with some minor variations, among the Qri7/Kae1/YgjD family proteins. The previously reported dimer formation was also observed in this new crystal form. Furthermore, a comparison with the structure of TobZ, which catalyzes a similar reaction to t(6)A biosynthesis, revealed the presence of a flexible loop that may be involved in tRNA binding.