## 2 Materials and Methods
### Electrochemical Oxidations of Veartryl Alcohol (VA)  
Oxidations of VA to VAH were performed using an Iso-tech laboratory DC power supply model IPS 303 DD. The experiments were carried out in a beaker (100 mL) fitted with a rubber bung, through which the electrochemical leads from the DC power supply entered the cell. Platinum wires were used as electrochemical leads. The electrochemical cell was placed in a thermostatted water bath at temperature of 23 \({}^{\circ}\)C, 40 \({}^{\circ}\)C or 50 \({}^{\circ}\)C. In a typical experiment, the 75 mL buffered solutions (pH 8.25) containing the complexes **1-7** (\(1.35\times 10^{-6}\) mol for 1%, but the amount of complex catalyst was evaluated in the range from 0 to 3%) and sodium chloride (2.1 g) as a supporting electrolyte were thermostatted at 40 \({}^{\circ}\)C. Then VA (19 \(\upmu\)L) was added, and the preset current was applied using the DC power supply at a fixed potential for 2 h.  
During the experiment, hydrogen gas evolved at the cathode. The solution was connected to a UV spectrophotometer through a peristaltic pump and a flow cell. Using this setup we were able to continuous record the electronic spectra of the solution and measure the rate of a VAH production. After electrochemical reaction, catalyst was removed by filtrating the solution through a short silica gel plug. The filtered solution was then separated in dichloromethane in the presence of saturated aqueous sodium chloride solution. The organic fraction was dried over magnesium sulphate and evaporated under reduced pressure. The residue was purified by column chromatography using a 1:1 mixture of ethyl acetate/hexane as eluent, and the \({}^{1}\)H NMR spectrum was recorded.  
Table 1 summarizes some of the experimental conditions for the electrochemical oxidations of VA to VAH.  
Single crystals of **1** suitable for X-ray diffraction (XRD) studies were obtained by slow evaporation of methanolic solutions at room temperature.  
Table 2 summarizes the detailed crystallographic data and refinement parameters for **1**. Measurements were made on a Bruker X8 APEXII CCD diffractometer employing graphite-monochromated _Mo-K\(\alpha\)_ radiation at cryogenic temperature (100 K). The structures were solved by direct methods [29] and finally refined by full-matrix least- squares base on F\({}^{2}\). An empirical absorption correction was applied using the program for empirical absorption correction of area detector data SADABS [30]. All non-hydrogen atoms were included in the model at geometrically calculated positions.  
Refinement of F\({}^{2}\) against all reflections. The weighted R-factor wR is based on F\({}^{2}\), conventional R-factors R are based on F, with F set to zero for negative F\({}^{2}\). The threshold expression of F\({}^{2}\)\(>\) 2\(\sigma\)(F\({}^{2}\)) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F\({}^{2}\) are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. Molecular graphics were done with ORTEP (Oak Ridge Thermal Ellipsoid Plot program) [31] and Mercury [32].  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Compound** & **TON a ** & **mmol VA Converted to VAH** & **Amount (mg) of VA Oxidized** & **Ef b/mol F-1 ** \\ \hline
1 & 84 & \(5.70\times 10^{-2}\) & 9.580 & 0.31 \\
2 & 84 & \(5.64\times 10^{-2}\) & 9.485 & 0.30 \\
3 & 68 & \(4.57\times 10^{-2}\) & 7.686 & 0.25 \\
4 & 80 & \(5.39\times 10^{-2}\) & 9.065 & 0.29 \\
5 & 40 & \(2.73\times 10^{-2}\) & 4.592 & 0.15 \\
6 & 40 & \(2.73\times 10^{-2}\) & 4.591 & 0.15 \\
7 & 40 & \(2.67\times 10^{-2}\) & 4.491 & 0.14 \\ \hline \end{tabular}
\end{table}
Table 1: Experimental conditions for the electrochemical conversion of VA to VAH (pH 8.25; 40 \({}^{\circ}\)C; 4 V).