A fluoroalkene-soluble tetrakis[heptadecafluorononyl]-substituted Pd(II)-phthalocyanine complex has been studied for olefin (styrene, 1-octene, trans-2-octene and cyclohexene) hydrogenation with molecular hydrogen in an organic/fluorous biphasic system [n-hexane/perfluoromethyl cyclohexane (PFMCH)]. The palladium complex was found to be an active catalyst for styrene (100% conversion, TON = 634) and 1-octene (92%, TON = 596) at 80°C and 15 bar of H 2 after 6 h of reaction time. The catalyst was recycled in nine consecutive reactions for the hydrogenation of styrene without the loss of activity or metal contamination.
Electrocatalytic activity, methanol tolerance and stability of three phthalocyanine (Pc) complexes (a heptadecafluorononyl-substituted mononuclear CoPc 1, a pentaerythritol-bridged ball-type dinuclear Co2Pc2 2 and a heptadecafluorodecyl-substituted, pentaerythritol-bridged ball-type dinuclear Co2Pc2 3) and the performance of dual catalysts of 2/Pt and 3/Pt, dispersed on a high surface area carbon substrate, Vulcan XC-72 (VC) and Nafion (Nf), towards oxygen reduction (OR) were investigated and compared by surface cyclic voltammetry, rotating disk electrode, rotating ring-disk electrode and chronoamperometry experiments in acidic medium. The VC/Nf/3 modified glassy carbon electrode showed much higher catalytic performance, compared to VC/Nf/2 and VC/Nf/1 modified ones. The long term stability of the VC/Nf/3 catalyst in acidic medium was better than that of VC/Nf/2. It was found that the VC/Nf/1, VC/Nf/2 and VC/Nf/3 catalysts are nearly insensitive to the presence of methanol. In the presence of 1 M methanol in the electrolyte, the catalytic performances of 2- and 3-based catalysts were much better than that of the Pt-based one. Thus, it was shown that the VC/Nf/2-Pt and VC/Nf/3-Pt dual catalysts can be good alternatives to VC/Nf/Pt as cathode catalysts in direct methanol fuel cells. Moreover, in the absence of methanol, the mixing of 3 with Pt resulted in the enhancement of catalytic activity for OR, when compared to 3 and even Pt in the high overpotentials region.
Heptadecafluorodecyl-substituted cofacial or ball-type bis-metallophthalocyanines (BTMPcs) have been prepared. The redox properties of the complexes and their catalytic activities for oxygen reduction were studied. The occurrence of stepwise one-electron redox processes during the voltammetric measurements in solution suggested the formation of stable mixed-valence species of the complexes, as a result of the intramolecular interactions between two cofacial Pc units. The ball-type Co(ii) complex displayed excellent catalytic activity for oxygen reduction which is probably due to the rigid cofacial structure involving two redox-active metal centers, which are capable of binding O(2). dc and ac conduction properties of BTMPcs [M = Co(ii) and Cu(ii) ]thin films have been investigated in the frequency range of 40 to 10(5) Hz and temperature 290-440 K. The dc results showed an activated conductivity dependence on temperature for all films. The analysis of the obtained data showed that the correlated barrier hopping (CBH) model is the dominant conduction mechanism for electron transport in the films. The gas sensing properties of the films for SO(2) were also investigated over the same temperature range. Although a very high response to SO(2) gas has been obtained for the film of at room temperature, the film of was not sensitive to the same gases.
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