4.5.3.4 Attempted Preparation ofRuOg from Ru(OEt)3 with prior refluxing
RuCh (Johnson Matthey, 2.63g, 10 mmol) was dissolved in 25 cm® of anhydrous ethanol and refluxed at 78 °C under a dry argon atmosphere for 2 hours until a green solution was obtained. To this solution 1.5M sodium ethoxide (either
155
freshly prepared via the method of Vogel*® or from Aldrich, 20 cm®, 30 mmol) was added and refluxing continued for a further 3 hrs after which a brown species, postulated to be ruthenium ethoxide had formed. After cooling to room temperature
HNO3 (9 cm® of I.IM acid diluted to 0.1 IM with anhydrous ethanol to give a RuiHgO ratio of 1:5 and a Ru:H+ ratio of 10:1) was added to this solution with stirring and the solution left to hydrolyse and condense for 30 minutes after which 30% H2O2 (Aldrich,
10 cm® was added). The final product was collected by centrifugation and dried at 90 °C under vacuum for 10 hours.
4.5.3.5 Attempted Preparation of RUO2 from Partially Substituted RuCft
Method was as for 4.5.3.4 with the following modifications: Two experiments
were performed, in the first 13.33 cm® rather than 20 cm® of 1.5M NaOEt were added
to the green RuCft solution and in the second 6.66 cm® of 1.5M NaOEt were added.
These amounts would allow only two and one of the Cl atoms bound to the mthenium
centre to be substituted. The ethoxides were again hydrolysed with HNO3 but no
peroxide has been added to date to determine whether any gelation will occur over a
4.5.3.6 Attempted Preparation of RnOg from Chloride-Dimethyl Sulphoxide- Ruthenium (III) Compounds
Method was as for 4.5.3.4 above only in these cases (DMSO)2H[^mw5-
RuCl4(DMSO)2] (5.56g, lOmmol) or Na[^ra«^'-RuCl4(DMSO)2] (4.2g,10mmol) were
used as the starting materials . Again no peroxide has to date been added to investigate whether gelation is possible before the oxidation step.
4.5.3.7 Attempted Preparation of RUO2 from (Et4N)[RuChMeCN] with prior refluxing
1.27g (2.8 mmol) of (Et4N)[RuClsMeCN] were dissolved in 8 cm® of anhydrous
ethanol and heated to reflux. After 30 minutes 7.5 cm® (11 mmol) of 1.5M Na O E t were
added and refluxing continued for three hours. After cooling to room temperature 0.25 cm® of 1.1 M H N O 3 were added. Product was left overnight to observe whether any
gelation had occured. A further 0.25 cm® of 1. IM H N O 3 was added.
4.5.3.8 High Temperature Hydrolysis Experiments
These experiments have to date been performed using RuCft and
(DMSO)2H[?ra«5-RuCl4(DMSO)2]. The ethoxides were generated as above. Cooling to
room temperature was not allowed, HNO3 was added to the reaction while the ethoxide species were still at 78 °C. Refluxing was continued for 15 hrs to allow hydrolysis and condensation at this higher temperature. After this time H2O2 was added with stirring
to oxidize the system which was then left to gel. In the experiment using RuCb the product was separated by centrifugation and dried at 90 °C under vacuum overnight.
Chapter 4: Non-Aqueous processing o f RuO2
4.6 References
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