Synthesis of Well-Defined, Surfactant-Free Co₃O₄ Nanoparticles:The Impact of Size and Manganese Promotion on Co₃O₄ Reduction and Water Oxidation Activity

Abstract: A surfactant-free synthetic route has been developed to produce size-controlled, cube-like cobalt oxide nanoparticles of three different sizes in high yields. It was found that by using sodium nitrite as salt-mediating agent, near-quantitative yields could be obtained. The size of the nanoparticles could be altered from 11 to 22 nm by changing the cobalt concentration and reaction time. These surfactant-free nanoparticles form ideal substrates for facile deposition of further elements such as manganese. The effect of size of the cobalt oxide nanoparticles and the presence of manganese on the reducibility of cobalt oxide to metallic cobalt was investigated. Similarly, the effect of these parameters was investigated with a visible light promoted water oxidation system with cobalt oxide as catalyst, together with [Ru(bpy) 3] 2+ light harvester dye and an electron acceptor. Graphical Abstract: A novel surfactant-free synthetic route has been developed to produce size-controlled, cube shaped cobalt oxide nanoparticles in high yields. [Figure not available: see fulltext.]. </p

Crystal structure of (η⁵ pentamethylcyclopentadienyl){bis(pentafluorophenyl)×thiomethylphenyl phosphine-κ₂ S,P)chloro-iridium(III) tetrafluoroborate

The salt (η⁵-pentamethylcyclopentadienyl){bis(pentafluorophenyl)thiomethylphenylphosphine-κ₂ S,P)chloroiridium(III) tetrafluoroborate, [(η⁵-C₅Me₅)IrCl{κ₂ S,P-(C₆F₅)₂PC₆H₄SMe-2}]BF₄, crystallizes as a conglomerate in the orthorhombic crystal system in space group P2₁2₁2₁ with unit cell parameters a = 9.9621(9) Å, b = 16.7793(15) Å, c = 18.5040(16) Å, V = 3093.1(5) ų, Z = 4, d calc = 2.014 g•cm⁻³. The structure of the S Ir, S S stereoisomer reveals three-legged piano stool geometry about Ir, with Cp*-Ir, Ir-P, Ir-S and Ir-Cl distances of 1.847(5) Å, 2.2791(14) Å, 2.3451(13) Å, and 2.3840(12) Å respectively

1,8-dimethylnaphthalene-bridged diphosphine ligands: synthesis and structural comparison of their palladium complexes

The synthesis of a new series of ligands with a 1,8-dimethylnaphthalene backbone is reported, 1,8-(R2PCH2)(2)C10H6, where R = Bu-t 1 (dbpn), Pr-i 2 (dippn), Cy 3 (dchpn) and Ph 4 (dphpn). The ligand 1 is structurally characterised by X-ray crystallography. A comparative structural study of the respective (diphosphine) Pd(dba) and (diphosphine) PdCl2 complexes is carried out, comparing the X-ray crystal structures of complexes 6, 7, 8, 10, 11 and 12. It is shown that the geometry at the metal is affected by not only ligand demands, but also by the palladium oxidation state and the electronic properties of the ligands. Two qualitative stability series are also identified: 9 &lt; 10 &lt; 11 approximate to 12 is observed, and P2Pd(dba) complexes are more stable than the corresponding P2PdCl2 complexes towards opening of the chelate ring. It is also concluded that the bite angle is heavily influenced by the electron donating properties of the ligand.</p

1,8-dimethylnaphthalene-bridged diphosphine ligands: synthesis and structural comparison of their palladium complexes

The synthesis of a new series of ligands with a 1,8-dimethylnaphthalene backbone is reported, 1,8-(R2PCH2)(2)C10H6, where R = Bu-t 1 (dbpn), Pr-i 2 (dippn), Cy 3 (dchpn) and Ph 4 (dphpn). The ligand 1 is structurally characterised by X-ray crystallography. A comparative structural study of the respective (diphosphine) Pd(dba) and (diphosphine) PdCl2 complexes is carried out, comparing the X-ray crystal structures of complexes 6, 7, 8, 10, 11 and 12. It is shown that the geometry at the metal is affected by not only ligand demands, but also by the palladium oxidation state and the electronic properties of the ligands. Two qualitative stability series are also identified: 9 &lt; 10 &lt; 11 approximate to 12 is observed, and P2Pd(dba) complexes are more stable than the corresponding P2PdCl2 complexes towards opening of the chelate ring. It is also concluded that the bite angle is heavily influenced by the electron donating properties of the ligand.</p

Effect of Rhodium Traces on the Reducibility of Silica-Supported Iron Particles

Fe/SiO2 and Rh-Fe/SiO2 catalysts with increasing Fe/Rh ratio have been prepared and characterized by TEM, XRD, oxygen adsorption and Mossbauer spectroscopy. It was confirmed that Fe/SiO2 catalysts cannot be reduced under hydrogen flow, to more than 50 % whatever the temperature in the 200-500 A degrees C range and shown that the presence of even a small amount of Rh (Fe/Rh a parts per thousand currency sign2,000) promoted the reduction of iron up to 85-95 %. This promoting effect also took place with a Fe/SiO2 + Rh/SiO2 physical mixture (Fe/Rh a parts per thousand currency sign2,000). Therefore, the occurrence of a hydrogen spillover effect may be involved in the observed process

CCDC 778656: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures