## 3 Results and Discussion
### Synthesis of the Metal Complexes
\begin{table}
\begin{tabular}{l c c c c c} \hline
**Atom** & **L1** & **L2** & **CuL1** & **CuL2** & **PdL2** \\ \hline \(1\) (NH) & & & & & \\ \hline \(2\) (C=S) & 174.6 & 175.5 & 171.7/174.8 & 168.3/175.4 & 172.3/172.9/174.0 \\ \hline \(3\) (NH) & & & & & \\ \hline \(4\) (C=O) & 163.0 & 164.8 & 162.9/169.5 & 164.9/166.1 & 160.3/166.4/167.0 \\ \hline \(5\) (CH) & 104.7 & 103.8/104.6 & 104.7/105.4 & 103.8/104.6/105.4/107.2 & 95.8/103.1/105.0 \\ \hline \(6\) (C) & 156.2 & 159.9 & 154.0/156.4 & 159.9/161.3 & 153.0/156.0/159.7 \\ \hline \(1^{\prime}\) & 20.2 & 32.7 & 20.1 & 32.7/39.3/39.6/40.9 & 33.4/34.2/38.6 \\ \hline \(2^{\prime}\) & & 19.6/20.2 & & 18.2/19.7/20.2/24.4 & 18.2/19.3/19.7 \\ \hline \(3^{\prime}\) & & 13.1/14.7 & & 13.1/13.6/14.7/15.7 & 12.9/15.4 \\ \hline DMSO & & & 40.3 & & \\ \hline \end{tabular}
\end{table} 
Table 8: \({}^{13}\)C NMR spectral data (in ppm) for L1, L2, and some of the complexes acquired with cross-polarization experiments, calibrated with the external reference \(\alpha\)-glycine carbonyl C (176.03 ppm). Figure 3: Solid-state CP MAS \({}^{13}\)C NMR of the ligand L1 (**a**) and its complex with copper (**b**). and 2.32 ppm for H-1\({}^{\prime}\), 1.54 ppm for H-2\({}^{\prime}\), and 0.87 ppm for H-3\({}^{\prime}\). These assignments were confirmed by \({}^{1}\)H-1\({}^{\prime}\)H COSY, \({}^{1}\)H-broadband decoupled \({}^{13}\)C-NMR, and DEPT-135 spectra and are shown in Table 9.  
The characterization of the CuL2 complex in solution was obstructed by its low solubility in various solvents including DMSO. In the \({}^{1}\)H NMR and \({}^{13}\)C NMR solution spectra of CuL2, only the free ligand resonances were present. In the solid-state \({}^{13}\)C NMR spectrum, there were resonances for both free and coordinated ligands. In the proton spectrum of CuL2 in DMSO-d6, a singlet at 2.54 ppm was observed for DMSO-h6 that was coordinated to Cu(II) during synthesis. The data about L2 and CuL2 are summarized and shown in Tables 10 and 11 and Figure 4a-c. The \({}^{13}\)C NMR spectrum of the L2 registered with the cross-polarization experiment showed seven signals. The two signals at 175.5 and 164.8 ppm were observed for the C=S and C=O groups, respectively. In the \({}^{13}\)C NMR spectrum with the cross-polarization experiment of CuL2, the signal for C=S was upfield shifted by 7.2 ppm. This showed that the C=S group of the ligand participated in the coordination with the copper. Also, a signal at 40.3 ppm was observed, confirming the coordination of DMSO-h6 to Cu(II). \begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**Atom**} & **L2** & **CuL2** & **PdL2** \\  & **(6-Propyl-2-Thoouracil)** & **Multiplicity (J, Hz)** & **Multiplicity (J, Hz)** \\ \hline
1 (NH) & 12.20 s & 12.20 and 10.77 s \\ \hline
2 (C=S) & - & - & - \\ \hline
3 (NH) & 12.31 s & 12.31 s & 12.32 and 10.87 s \\ \hline
4 (C=O) & - & - & - \\ \hline
5 & 5.67 s & 5.67 s & 5.68 and 5.31 s and t(1.8) \\ \hline
6 & - & - & - \\ \hline
1\({}^{\prime}\) & 2.32 t(7.5) & 2.32 t(7.4) & 2.32 and 2.25 t(7.3) and t(7.3) \\ \hline
2\({}^{\prime}\) & 1.54 s(7.4) & 1.54 s(7.5) & 1.54 and 1.48 s(7.6) and m \\ \hline
3\({}^{\prime}\) & 0.87 t(7.4) & 0.88 t(7.3) & 0.87 and 0.82 t(7.3) and m \\ \hline DMSO & - & 2.54 s & 2.54 s \\ \hline \hline \end{tabular} In DMSO-d6 solution.  
\end{table} 
Table 10: \({}^{1}\)H NMR spectral data (in ppm) for complexes of 6-propyl-2-thiouracil with Cu(II) and Pd(II). \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multicolumn{1}{c}{**Atom**} & \(\boldsymbol{\delta\)**(\({}^{13}\)C) ppm**} & **DEPT -135** & \(\boldsymbol{\delta\)**(\({}^{1}\)H) ppm**} & **Multiplicity (J, Hz)** & \({}^{1}\)**H-\({}^{1}\)H COSY** \\ \hline
1 (NH) & - & - & 12.20 & s \\ \hline
2 (C=S) & 176.08 & C & - & \\ \hline
3 (NH) & - & - & 12.31 & s \\ \hline
4 (C=O) & 161.22 & C & - & \\ \hline
5 & 103.06 & CH & 5.67 & s \\ \hline
6 & 156.74 & C & &  
There are six couples of signals in the \({}^{1}\)H NMR spectrum of Pd(II) complex with 6-propyl-2-thiouracil.