Comparison and Synthesis of Molybdenum Carbonyl Complexes Substituted with Mono- and Bis-Triphenylphosphine Ligands for Hydrocracking of Vacuum Residue

(PPh3)Mo(CO)5 and (PPh3)2Mo(CO)4 were synthesized by the reaction of molybdenum hexacar-bonyl with triphenylphosphine and applied as precursors to hydrocracking of vacuum residue under high-pressure and high-temperature conditions. (PPh3)2Mo(CO)4 could also be synthesized by the reaction of (PPh3)Mo(CO)5 with triphenyl phosphine. A commercial precursor (Mo-octoate) for hydrocracking of vacuum residue was used for comparison. The thermal decomposition behavior of (PPh3)Mo(CO)5, (PPh3)2Mo(CO)4, and Mo-octoate was also examined by the thermogravimetric analysis. The TGA curve of (PPh3)Mo(CO)5 and (PPh3)2Mo(CO)4 showed a similar weight-loss pattern. (PPh3)Mo(CO)5 and (PPh3)2Mo(CO)4 were decomposed into Mo metal and ligands rapidly in the range of 140 °C~270 °C. There were no ligands bound to a metal center of (PPh3)Mo(CO)5 and (PPh3)2Mo(CO)4 at the reaction temperature (430 °C) of hydrocracking. The amount of coke formed after hydrocracking over (PPh3)Mo(CO)5 and (PPh3)2Mo(CO)4 was 2.3% and 0.5%, respectively. Upgrading the qualities of heavy oils is an important issue in the energy industry. It is not easy to achieve the complete conversion of vacuum residue due to coke forming during hydrocracking of vacuum residue. This study showed that (PPh3)2Mo(CO)4 was considerably effective in reducing coke formation.

Ultrafast Photochemistry of a Molybdenum Carbonyl-Nitrosyl Complex with a Triazacyclononane Coligand

Transition metal complexes capable of releasing small molecules such as carbon monoxide and nitric oxide upon photoactivation are versatile tools in various fields of chemistry and biology. In this work,...

Synthesis of Pt-based alloy nanostructures

SYNOPSIS Optimizing the catalytic performance of multimetallic nanoparticle (NP) catalysts demands a concrete understanding of their design, while preferentially deploying wet chemical synthesis procedures to precisely control surface structural properties. Here we report the influence of reductants such as hydrogen-rich tetrabutylammonium borohydride (TBAB) and carbon monoxide-rich molybdenum carbonyl (Mo(CO)6) on the shape and morphological evolution of Pt-based binary (PtNi and PtCo) and ternary (PtNiAu and PtCoAu) nanostructures derived from a homogeneous solution of amine-based surface active agents (surfactants) in a high boiling point solvent. We successfully synthesized nanostructures exhibiting well-defined and composition-controlled surfaces deploying a one-pot synthetic approach. The development of the surface properties was, however, observed to be alloy-specific. The resultant highly monodisperse alloy NP with narrow size distributions and facet-oriented surfaces are expected to display enhanced functionality as catalysts for utilization in specific chemical reactions. Keywords: catalyst. platinum alloy, nanoparticles, synthesis, mixed-metal nanostructure.

Hydrostannylation of carbon dioxide by a hydridostannylene molybdenum complex

Reaction of the aryltin(ii) hydrides with molybdenum carbonyl afforded Mo(CO)5{Sn(AriPr6)H}, (1), or Mo(CO)5{Sn(AriPr4)(THF)H} (2), respectively, in which 1 reacted with carbon dioxide, to yield Mo(CO)5{Sn(AriPr6)(κ2-O,O′-O2CH)}, (3).