## 3 Results and Discussion
### Catalysis  
Ruthenium nanoparticles have widely been used in hydrogenation processes [103; 104; 105; 106; 107; 108]. The catalytic activity of Ru@M-Ethylene PMO NPs was examined in a hydrogenation reaction of aromatic compounds as a model reaction. The reduction reaction was performed in heptane solvent at temperatures of 80-120 \({}^{\circ}\)C under hydrogen pressures of 100-400 psi with 0.1 mol% of the ruthenium catalyst. From the results presented in Table 1, it can be concluded that the catalyst's efficacy and activity were very high in catalyzing this hydrogenation reaction. Thus, benzene and toluene were fully hydrogenated in one hour and gave cyclohexane and methylcyclohexane, respectively (Table 1, entries 1 and 2, respectively). The hydrogenation of ethylbenzene and propylbenzene required a longer time and a higher temperature to provide the fully hydrogenated products in excellent yields (Table 1, entries 3 and 4, respectively). The substrates \(m\)-xylene and 1,3,5-trimethylbenzene could be converted after 12 h at 120 \({}^{\circ}\)C into a mixture of isomers of alkylated cyclohexanes (Table 1, entries 5 and 6). The catalyst exhibited good reactivity in the hydrogenation of aromatic compounds substituted with electron withdrawing groups. For example, the hydrogenation of ethyl benzoate under 400 psi H\({}_{2}\) and at 120 \({}^{\circ}\)C gave ethyl cyclohexancarboxylate after 12 h in complete conversion. When nitrobenzene was hydrogenated under the same conditions, cyclohexylamine was produced in quantitative yields. To demonstrate our novel catalytic system activity, further kinetic tests on toluene were performed. From the high turnover number (TON) and turnover frequency (TOF) values displayed in Table 2, it can be concluded that the high catalytic activity of the catalyst is preserved at very high substrate concentrations under the same reaction conditions of 400 psi of hydrogen and a temperature of 80 \({}^{\circ}\)C.  
In addition, the recyclability of the catalyst was tested in the hydrogenation of toluene with substrate: catalyst ratio of 2000:1 under 400 psi H\({}_{2}\) at 80 \({}^{\circ}\)C. The catalyst was reused four times in this reaction without any loss of its reactivity. Inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated that there was no leaching of the ruthenium catalyst during the hydrogenation reaction. Figure 12: STEM-EDX mapping analysis of Ru@M-Ethylene PMO NPs. by supporting metal nanoparticles in their mesoscopic channels. The resulting magnetic PMO NPs were loaded with ruthenium oxide nanoparticles without the need for any stabilizing agent. The new magnetic catalytic system was applied in the hydrogenation reaction of aromatic compounds and it exhibited a high catalytic performance. Introducing the magnetic nanoparticles in these nanosystems greatly improves the catalyst's separation and recovery from the reaction medium and eliminates the cumbersome workup and filtering processes. We believe that this successful strategy for designing pure magnetic PMO nanomaterials can provide new opportunities in many catalytic and other scientific areas. The following are available online at [[http://www.mdpi.com/2076-3417/10/17/5769/s1](http://www.mdpi.com/2076-3417/10/17/5769/s1)]([http://www.mdpi.com/2076-3417/10/17/5769/s1](http://www.mdpi.com/2076-3417/10/17/5769/s1)), Figure S1: XRD pattern of Ru@Ethylene PMO NPs, GC chromatographs and \({}^{1}\)HNMR spectra of the hydrogenation products. Conceptualization, R.A.-R.; methodology, R.A.-R. and S.O. ; formal analysis, R.A.-R. and S.O. ; investigation, S.O. ; resources, R.A.-R.; data curation, S.O. ; writing--original draft preparation, S.O. ; writing--review and editing, R.A.-R. and S.O. ; visualization, S.O. ; supervision R.A.-R.; project administration, R.A.-R.; funding acquisition, R.A.-R. All authors have read and agreed to the published version of the manuscript. This research was funded by Casali Foundation. [PERSON] is grateful to the Ministry of Science and Technology of Israel for her fellowship.