## 3 Results
\begin{table}
\begin{tabular}{c c} \hline
**MW-Reaction Conditions** & **Pressure/atm** \\ \hline Control (without catalyst) & 1.3 \\ TBHP & 5.3 \\ H\({}_{2}\)O\({}_{2}\) & 5.6 \\ air & 1.0 \\ \hline \end{tabular}
\end{table} 
Table 3: MW reactor maximum pressure for the oxidation of cyclohexane to cyclohexanol and cyclohexanone catalyzed by Au NTs. overheating (\"hot-spot\" effect), and (iii) the non-thermal effects such as influence on the pre-exponential factor A in the Arrhenius equation [33]. It is also worth to notice that the attained maximum yield value in the present study is also higher than the reported [34] for the currently industrial (commercial) process with the advantage of being much more selective (100% selectivity was obtained, see entry 4 of Table 1) and obtained under mild conditions. The stability of the gold nanotriangles in the oxidative reaction medium was assessed by UV-vis spectrophotometry, through the localized surface plasmonic resonance (LSPR) of the AuNTs before and after the reaction. As depicted in Figure 6, after the catalytic reaction, only a very small \(\lambda_{\text{max}}\) shift from 533 nm (before the reaction) to 536 nm (after the reaction) of the LSPR was detected. As a common rule, bigger nanoparticles, as well as more complex morphologies, lead to longer red-shifted absorptions in the LSPR and therefore no significant aggregation of the Au NTs appears to occur during the catalytic reaction. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Entry**} & **Catalyst** & \multirow{2}{*}{**Additive**} & \multicolumn{2}{c}{**Yield/\% b**} & \multirow{2}{*}{**Total TON c**} & \multirow{2}{*}{**Conversion/\%**} \\  & **Amount/umol** & & & **CyO (K)** & & **CyOH (A)** & & **Total** \\ \hline
1 & 5 & — & 0.2 & — & 0.2 & 2 & 0.5 \\
2 & 10 & — & 0.3 & — & 0.3 & 2 & 0.6 \\
3 & 20 & — & 0.5 & — & 0.5 & 1 & 0.9 \\
4 & 30 & — & 2.0 & — & 2.0 & 3 & 2 \\
5 & 5 & HNO\({}_{3}\) & 0.6 & — & 0.6 & 6 & 0.8 \\
6 d  & 20 & — & 0.2 & 1 & 0.3 \\
7 d  & 20 & HNO\({}_{3}\) & 0.3 & — & 0.3 & 1 & 0.3 \\
8 e  & 20 & — & — & — & — & — \\ \hline \end{tabular}  
* Reaction conditions, unless stated otherwise: CyH (5.0 mmol), TBHP (70% aq. solution, 10.0 mmol), n(additive)/n(substrate) = 4. b Based on gas chromatography (GC) analysis, after treatment with PPh\({}_{3}\); molar yield (%) based on substrate, that is, moles of products (cyclohexanol and cyclohexanone) per 100 mol of cyclohexane.
* TON = Total turnover number (moles of cyclohexanol + cyclohexanone per mole of catalyst). d H\({}_{2}\)O\({}_{2}\) (30% aq. solution, 10.0 mmol). e Using air as oxidant.  
\end{table} 
Table 4: Selected data \({}^{a}\) for the oxidation of cyclohexane to cyclohexanol and cyclohexanone during 3 h at 50 \({}^{\circ}\)C using conventional heating. Figure 6: Absorption spectra (400 – 700 nm) of the Au NTs before and after the catalytic oxidation reaction. By analogy with reported mechanisms for different types of M\({}^{n/n-1}\) metal systems [6; 7; 35], the proposed mechanism for the present Au NTs/TBHP system follows (reactions (1)-(9), Scheme 3). Firstly, Au-catalyzed decomposition of TBHP occurs, leading to ROO and RO radicals upon oxidation by Au\({}^{n}\) or reduction by A\({}^{n-1}\) according to reactions (1) and (2), respectively. Then, H-abstraction from CyH by RO leads to the formation of cyclohexyl radical (Cy) (reaction (3)). CyOO is formed by the reaction of Cy with dioxygen (reaction (4)), and CyOOH can then be formed upon H-abstraction from TBHP by CyOO (reaction (5)). Au-assisted decomposition of CyOOH to CyOO and CyO (reactions (6) and (7)) leads to the formation of the desired products: cyclohexanol (CyOH) and cyclohexanone (Cy\({}_{-H}\)=O), according to reactions (8) and (9)). This work created the possibility of using non-supported gold nanoparticles towards cyclohexane oxidation under mild conditions using peroxide as oxidant.