## 3 Results
### Crystal Structure of **1**  
Single crystals of complex **1**, suitable for X-ray diffraction studies, were obtained as described in the 2.6 section of crystallographic studies. The crystal structure of the monomeric unit is shown in Figure 4a, while Figure 4b shows the \(\upmu\)-aquo dimers resulting from the non-covalent interactions between the monomers. Table 4 collects main bond distances, and Table 5 summarizes main angles for **1**. Figure 4: **(a)** ORTEP view of the monomeric unit for **1** with numbering scheme; **(b)** crystal structure of the dimeric entity for **1** (manganese ion in magenta, nitrogen in blue, oxygen in red and carbon in grey). Figure 3: Cyclic voltammogram for **3** at scan rate of 0.02 V s\({}^{-1}\). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Compound** & **VA to VAH 1** ** & **Mn-O\({}_{\mathrm{axial}}\)1 ** & **E\({}_{\mathrm{ox}}\) (V)** & **E\({}_{\mathrm{red}}\) (V)** \\ \hline
1 & 42.2 \(\pm\) 4 & 65 \(\pm\) 5 & 2.2495(11) & 43 & \(-\)0.085 & \(-\)0.165 \\
2 & 41.8 \(\pm\) 3 & 35 \(\pm\) 1 & 2.257(2) & 42 & \(-\)0.010 & \(-\)0.098 \\
3 & 38.5 \(\pm\) 5 & 54 \(\pm\) 5 & un. & 43 & \(-\)0.034 & \(-\)0.114 \\
4 & 39.9 \(\pm\) 6 & 50 \(\pm\) 3 & 2.270(6) & 42 & \(-\)0.154 & \(-\)0.237 \\
5 & 20.2 \(\pm\) 3 & 2.2 \(\pm\) 0.4 & un. & 49 & \(-\)0.116 & \(-\)0.256 \\
6 & 20.1 \(\pm\) 2 & 2.4 \(\pm\) 0.3 & un. & 49 & un. & un. \\
7 & 19.8 \(\pm\) 3 & 1.9 \(\pm\) 0.4 & un. & un. & \(-\)0.034 & \(-\)0.144 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: VA to VAH conversion, peroxidase activity, Mn-O\({}_{\mathrm{axial}}\) distances, EPR hyperfine coupling and redox potentials for the complexes. The monomer is composed by an approximately octahedral [MnL\({}^{1}\)(H\({}_{2}\)O)(N(CN)\({}_{2}\))] unit, with the Schiff base tetracoordinated to the metal ion through its oxygen-nitrogen-nitrogen-oxygen (ONNO) donor atoms. This coordination of the Schiff base in the equatorial plane forms three chelate rings with the metal ion (two six-membered and one five-membered), thus providing high stability to the [MnL]\({}^{+}\) units. The bis-deprotonated Schiff base ligand is tightly bound to the manganese ion by the nitrogen limitic and oxygen phenolic atoms (Mn-N\({}_{\rm{imine}}\) bond lengths of 1.9828-1.9834 A and Mn-O\({}_{\rm{phenol}}\) of 1.8837-1.8895 A which are typical of such complexes [14; 15; 16]). The distortion of the octahedron is derived from the considerably longer axial distances with respect to the equatorial ones. The axial positions are occupied by a capping water molecule (Mn-O6 with a bond distance of 2.2495(11) A) and a dicyanamide molecule (Mn-N7 with a bond distance of 2.3037(13) A). The ratio between the Mn-O axial and Mn-O equatorial distances in the crystal structure is 1.194, which is a way to express the tetragonal distortion factor for the octahedron around the manganese ion. This effect has been previously studied by us for this type of complex [17; 27], and a correlation between the tetragonal distortion and the catalytic performance in different redox processes has been established [17; 27]. This can be explained because the tetragonal elongation enhances the ability of an axial position where the substrate molecule can be subsequently accommodated in this site, following an inner-sphere electron-transfer mechanism. A rich network of non-covalent interactions stabilizes dimeric entities by the extension of the monomeric units. The octahedral entities are linked in pairs by \(\mu\)-aquo bridges between the hydrogen atoms of the axial water molecules and the phenoxy and ethoxy oxygen atoms from the neighboring Schiff base ligands. \(\pi\)-\(\pi\) stacking interactions between parallel aromatic rings from neighboring ligands are also enriching the final supramolecular structure.