## 3 Results and Discussion  
### Synthesis of the Metal Complexes  
The interaction of metal ions with L1 and L2 in a molar ratio of metal:ligand:base (1:4:2) resulted in the formation of the complexes with suggested formulas shown in Table 1. The results of the elemental analysis for the metal ions were determined by Microwave Plasma-Atomic Emission Spectrometry. They can be used to determine the tentative average composition of different complexes. All the complexes were stable in air and moisture and their solubility was limited. We found that the reaction of L1 and L2 with the transition metal ions afforded a 40-72% yield of a stable solid compound. The complexes obtained had a yellow-green or brown color and limited solubility in DMSO and DMF, except CuL2 (soluble in DMSO only); the complexes were insoluble in water, THF, C\({}_{2}\)H\({}_{5}\)OH, EtOAc, and cyclohexane. The analytical data including the yield percentage of the complexes are presented in Table 2.  
IR Verification of the structures of the metal complexes can be easily achieved by comparing the IR spectra of the free ligands with that of their metal complexes. The selected experimental data from the IR spectra of the complexes CuL1 and PdL1 and of the free ligand (in cm\({}^{-1}\)) is shown in Table 3.  
In the IR spectra of the free ligand L1, the bands at 3115 cm\({}^{-1}\) and 3080 cm\({}^{-1}\) were observed, which may refer to the stretching vibrations of N-H groups. In the spectrum of the Cu(II) complex, the same bands were observed at the same frequencies. In the IR spectrum of the Pd(II)L1, these bands were shifted to the lower frequencies compared to the free ligand bands with 4 cm\({}^{-1}\) and 9 cm\({}^{-1}\), respectively. This shows that the two N-H groups of the ligand participate in the coordination of the palladium complex. The L1 IR bands at 1676 and 1242 cm\({}^{-1}\) can be attributed to the stretching vibration of C\({}^{4}\)=O and C\({}^{2}\)=S groups, respectively. The stretching vibration of C\({}^{4}\)=O in the CuL1 complex was shifted to the lower frequency with 39 cm\({}^{-1}\) compared to this stretching in the free ligand. The same bands in the IR spectrum of the PdL1 complex did not change. In the ATR spectrum \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Metal Complex** & **Composition \({}^{*}\)** & **Formula** & **Molecular Weight** & **W(M)\% Calc./Exp.** \\ \hline
**CuL1** & [3 LCu.(DMSO)] & C\({}_{17}\)H\({}_{24}\)N\({}_{6}\)O\({}_{4}\)S\({}_{4}\)Cu & M = 568.22 g/mol & 11.2/11.6 \(\pm\) 0.6 \\ \hline
**PdL1** & [5 LPd.(DMSO)]\({}_{2}\)O & C\({}_{27}\)H\({}_{38}\)N\({}_{10}\)O\({}_{5}\)S\({}_{6}\)Pd & M = 913.46 g/mol & 11.6/11.1 \(\pm\) 0.6 \\ \hline
**CuL2** & [LCu.H\({}_{2}\)O.(OH\({}^{-1}\))\({}_{2}\)(DMSO)] & C\({}_{11}\)H\({}_{26}\)N\({}_{2}\)O\({}_{6}\)S\({}_{3}\)Cu & M = 442.07 g/mol & 14.4/14.3 \(\pm\) 0.7 \\ \hline
**PdL2** & [4 LPd.(DMSO)]\({}_{2}\)J\({}_{2}\)O & C\({}_{32}\)H\({}_{54}\)N\({}_{8}\)O\({}_{7}\)S\({}_{6}\)Pd & M = 961.63 g/mol & 11.1/11.5 \(\pm\) 0.5 \\ \hline \end{tabular} \({}^{*}\) Putative average composition of different complexes.  
\end{table} 
Table 1: Elemental analysis data for the metal ions of the complexes.