Isocyanide [AuX(CNPy-2)] (X = Cl, C6F5, fluoromesityl, 1/2 octafluorobiphenyl) and carbene [AuX{C(NR1R2)(NHPy-2)}] (R1R2NH = primary or secondary amines or 1/2 primary diamine) gold(I) complexes have been synthesized and characterized. For X = Cl, the carbene complexes show aurophilic interactions. The fragment NHPy-2, formed in the carbenes, can give rise to intra- (for primary amines) or intermolecular (for secondary amines) hydrogen bonds, depending on the amine used. These bonds and contacts have been studied in the solid state and in solution. The intermolecular hydrogen bonds are split in an acetone solution, but the intramolecular ones, which close a six-membered ring, survive in solution. Except for the fluoromesityl derivatives, the carbene complexes display luminescent properties.
This paper reports the synthesis, liquid crystal behavior, and chargetransport properties in the mesophase of isocyano-triphenylene gold, copper, palladium, and platinum complexes [MX(CNR)] (CNR = 2-(6-(4isocyanophenoxy)hexyloxy)-3,6,7,10,11-pentakisdodecyloxytriphenylene; M = Au, X = Cl, C 6 F 5 , C 6 F 4 OC 10 H 21 , CN;, and [MX 2 (CNR) 2 ] (M = Pd, Pt; X = Cl, Br, I, and M = Pt, X = CN). The thermal and electronic properties of these materials are modulated by the metal fragment. The complexes that display columnar mesomorphism are those that support more than one triphenylene per molecule or those that produce a similar effect by dipole−dipole interactions between the metal groups. These circumstances improve the balance of favorable enthalpic interactions versus unfavorable entropic contributions into a columnar stacking. Hybrid inorganic/organic dual columnar mesophases with high SCLC hole mobility along the columnar stacking, above 1 cm 2 V −1 s −1 , have been found. It is worth noting that the dicyanoplatinum complex displays mesophase phosphorescence based on Pt•••Pt interactions.
Gold complexes of 4-isocyanobenzoic acid, [AuX(CNC(6)H(4)CO(2)H)] (X = C[triple bond]C-C(6)H(4)-C(9)H(19), C(6)F(5), C(6)F(4)OC(6)H(13), C(6)F(4)C(6)F(4)Br) and [(mu-4,4'-C(6)F(4)C(6)F(4)){Au(CNC(6)H(4)CO(2)H)}(2)], have been isolated. These metallo-acids are luminescent. The single crystal X-ray diffraction study of [Au(C(6)F(5))(CNC(6)H(4)CO(2)H)](infinity) confirms a rod-like structure of the molecule, with a linear coordination around the gold atom, which extends into a supramolecular entity supported by hydrogen bond, gold-gold, and fluorophilic (F(ortho) ... F(meta)) interactions. The carboxylic acid group of the gold isocyanide complexes acts also as a hydrogen donor towards the hydrogen acceptor decyloxystilbazole, affording some hydrogen-bonded supramolecular liquid crystals.
Gold nanoparticles have been deposited on three kinds of carbon nanotubes (CNTs), including nitrogen‐doped CNTs, by three different methods, namely, impregnation, organometallic decomposition, and deposition–precipitation. The choice of the gold precursor, the support, and the preparation procedure is critical for the control of the size and location (on or inside the nanotubes) of the gold nanoparticles. These catalysts were tested for the selective oxidation of CO in a hydrogen‐rich atmosphere. We have shown that the use of nitrogen‐doped CNTs as a support permits one to reach much higher activity and selectivity at low temperaturethan with the other CNT supports. This catalyst also shows a good stability under reaction conditions without detectable sintering.
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