Single crystal oxide filaments

Surface science studies of CO oxidation on Au(llO) single crystals have been made previously in which a Pt filament was used to adsorb oxygen adatoms ( o 0.25) on the Au(llO) surface and a CO titration was performed subsequently (7). CO did react to form CO2 with Eapp = 2 1 kcal/mole. Since CO was not observed to adsorb on Au(llO) at 125 K, it is only physisorbed (as on Au(lll)) and we can estimate that Elh = 7 kcal/mol on Au(llO). The difference from Au(lll) is probably due to a weaker Au-O bond on Au(lll) which leads to a lower barrier for reaction. No surface carbonate was formed from CO2 + Oa on Au(llO) either (7). This is in contrast to the behavior on Ag. Exposing oxygen covered Ag(llO) (16) or Ag(lll) (17) to CO2 produces carbonate species which are stable to 485 K on the surface. 

Adenine (10 g, 0.074 mol) was dissolved in hot HOAc (60 mL). The solution was then cooled to 20 °C, 30% aq HjOj (37 mL) was added, and the solution was allowed to stand at rt for 2.5 d. At the end of this time a substantial proportion of the product had crystallized. This material (7.0 g) was collected and washed with a little HOAc. Further batches (1,6 and 0.2 g) were collected 3.5 and 4.5 d after the start of the oxidation. These crops each showed single spots on ascending paper chromatography. Further oxide (0.6 g) could be obtained from the final filtrate after destroying the HjOj by the addition of Pd/C and removing some of the HOAc in vacuo. The total yield was 9.4 g (84%). Crystallization of adenine I-oxide from boiling HjO yielded white filamentous crystals decomposition point 297-307°C. 

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