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Fermi surfaces of transition metals, which describe all thermodynamical and transport quantities of solids, often fail to be modeled by one-electron mean-field theory due to strong correlations among the valence electrons. In addition, relativistic spin–orbit coupling pronounced in heavier elements lifts the degeneracy of the energy bands and further modifies the Fermi surface. Palladium and rhodium, two 4d metals attributed to show significant spin–orbit coupling and electron correlations, are ideal for a systematic and fundamental study of the two fundamental physical phenomena and their interplay in the electronic structure. In this study, we explored the Fermi surface of the 4d noble metals palladium and rhodium obtained via high-resolution constant initial state momentum microscopy. The complete 3D-Fermi surfaces of palladium and rhodium were tomographically mapped using soft X-ray photon energies from 34 eV up to 660 eV. To fully capture the orbital angular momentum of states across the Fermi surface, the Fermi surface tomography was performed using p- and s- polarized light. Applicability and limitations of the nearly-free electron final state model in photoemission are discussed using a complex band structure model supported by experimental evidence. The significance of spin–orbit coupling and electron correlations across the Fermi surfaces will be discussed within the context of the photoemission results. State-of-the-art fully relativistic Korringa–Kohn–Rostoker (KKR) calculations within the one-step model of photoemission are used to support the experimental results. • High-resolution complete Fermi surfaces of palladium and rhodium crystals. • Limitations of nearly free electron photoemission final-state model. • Complex band structure from photoemission final-states in low energy regime. • Observation of final-state self-energy footprint as kinks in photoemission spectra. • Experimental resolution of fine structures in fully relativistic Fermi surfaces. [ABSTRACT FROM AUTHOR]

Abstract: The time-dependence of tritium absorption on aged (3 years) palladium powder in α and α&β areas has been experimentally measured for initial tritium pressures in the range 40–200kPa and tritide temperatures in the range 22–65°C. The results show that the absorption rate increases with initial tritium pressure (at constant temperature) in both α and α&β areas, and decreases with increasing temperature at constant pressure in the α&β area. The overall tritium absorption process of aged palladium is determined by two steps: (1) the chemisorption reaction on the surface of palladium tritide at the start of the absorption, when only the temperature of the palladium tritide influences the chemisorption reaction rate; (2) diffusion of tritium atoms through tritide during tritium absorption, when both the tritide temperature and the initial pressure of tritium molecules affect the reaction rate. The diffusion activation energy and chemisorption activation energy are 13.66 and 19.38kJ/mol, respectively at 22–65°C, the sum of which agrees with absorption and desorption transition enthalpies of the same unaged and aged palladium tritide at 35–75°C. [Copyright &y& Elsevier]

Abstract: The absorption and desorption pressure–composition isotherms in a palladium–tritium system have been experimentally measured at 35, 50, 65 and using the PVT method for tritium storage up to 3 years. Results show that the storage properties are remarkably well preserved during aging, and only small modifications of P–c isotherms are observed: a decrease of plateau pressures and shifts of single phase regions toward greater stoichiometries. At a temperature in the range , absorption transition enthalpies of aged palladium tritide is 30.1kJ/mol, desorption transition enthalpies of the unaged is 34.6kJ/mol and absorption–desorption transition entropy of the aged palladium tritide is less than the unaged. The hysteresis coefficient decreases with the temperature. [Copyright &y& Elsevier]

Abstract: The oxazepine ring systems containing pyridazinone moiety were constructed via palladium-catalyzed intramolecular coupling reaction. The best conditions for this reaction were Pd(OAc)2 as a palladium source, 1,1′-bis(diphenylphosphino)-ferrocene (DPPF) as the ligand, and K2CO3 as base at 80°C in toluene. The products have potential applications as biological and medicinal relevant compounds. [Copyright &y& Elsevier]

A facile synthesis of styrylcoumarins based on Palladium-catalyzed reaction of coumarin diazonium salts with substituted styrenes is described. The reactions produced a series of 7-styrylcoumarins in good yields under mild conditions. The absorption and emission spectra of different styrylcoumarins were compared and discussed. Although the λa,max of the styrylcoumarins changed only slightly with a p-substituted styrene, the λe,max produced a blue shift which increased with the electron-withdrawing ability of the p-substituted group. The p-CH3 of styrylcoumarin caused a red shift of ca. 20 nm and also a higher fluorescence quantum yield. Styrylcoumarins with o, p-CN obtained well-resolved vibrational bands and the latter possessed higher fluorescence quantum yield. In addition, a coumarin extended at both the 3-positions with benzene and 7-position with p-chlorostyrene had better fluorescence properties. [Copyright &y& Elsevier]

A Pd-tBuONO co-catalyzed scalable and practical synthesis of indoles with molecular oxygen as terminal oxidant is developed. Either terminal or internal 2-vinylanilines could be smoothly converted to desired indoles under one general condition. This method has been evaluated in the large scale synthesis of indomethacin and a potential anti-breast cancer drug candidate 1. [ABSTRACT FROM AUTHOR]

The separation factors of the palladium-hydrogen system were experimentally measured at different temperatures ranging from 248 to 303 K after aging for up to 3.5 years by tritium. The results showed a remarkable hydrogen isotope effect in the aged palladium-hydrogen system compared to the raw system. The hydrogen-deuterium separation factor of the palladium-hydrogen system aged by tritium was correlated to temperature and hydrogen/deuterium ratio in the solid phase of palladium hydride. [ABSTRACT FROM AUTHOR]

Magnetic Pd-Ni bimetals with various compositions were synthesized by a one-pot reaction, in which chain-like Pd-Ni bimetals formed through the self-assembly of Pd-Ni nanoparticles. The self-assembly behaviour of the Pd-Ni bimetals gradually changes with the changes in composition. The Pd-Ni nanoparticles form simple chains at lower Pd content, while the Pd-Ni bimetals take on a beads-on-string structure composed of sphere-shaped Pd-Ni-nanoparticle assemblies at higher Pd content. Magnetic hysteresis loops show that Ni-rich assemblies have a higher saturation magnetization than Pd-rich assemblies. The formation mechanism for these Pd-Ni assemblies is proposed, in which the self-assembly behaviours are controlled by the competition of the surfactant interaction and the magnetic dipole interaction. The catalytic activity and selectivity of the hydrogenation of acetophenone over these Pd-Ni bimetals depend on their compositions. [ABSTRACT FROM AUTHOR]

Abstract: A simple and efficient activation process was conducted by deposition of palladium (Pd) nanoparticles on PMMA surface using a microwave-assisted polyol method with ethanol used as the reductant. The newly synthesized Pd nanoparticles were utilized as an activator for electroless nickel deposition. TEM images revealed that Pd nanoparticles of size 4–6nm are formed evenly over the PMMA surface. A tight, smooth and continuous Ni plating layer was coated on these Pd nanoparticle activated PMMA microspheres. In contrast, a rough and discontinuous Ni film was obtained for the sample activated with a conventional sensitization/activation procedure. [Copyright &y& Elsevier]