## 2 Materials and Methods
### Synthesis of the Complexes  
Experimental procedure and characterization data for **1**, **3**, **5** and **6** are collected below. Synthesis and characterization of complexes **2**[26], **4**[17] and **7**[27] have been already reported (see Table S1). Mn\({}_{2}\)L\({}^{1}\)\({}_{2}\)(H\({}_{2}\)O)\({}_{2}\)(N(CN)\({}_{2}\))\({}_{2}\) (**1**) was obtained by a procedure which has been already reported [27] using 0.15 g (0.42 mmol) of H\({}_{2}\)L\({}^{2}\), 0.12 g (0.42 mmol) of Mn(CH\({}_{3}\)COO)\({}_{2}\) and 0.04 g (0.42 mmol) of NaN(CN)\({}_{2}\). Experimental details are available in the Supplementary Materials section. Yield: 0.15 g (70%). Calculated Elemental Analysis for C\({}_{44}\)H\({}_{48}\)Mn\({}_{2}\)N\({}_{10}\)O\({}_{10}\) (986.8): C, 53.5; H, 4.9; N, 14.2. Found: C, 53.0; H, 4.9; N, 13.9%. Electrospray mass spectrometry (MS ES) (_m/z_): 409 [MnL\({}^{1}\)]\({}^{+}\); 475 [MnL\({}^{1}\)(N(CN)\({}_{2}\))]\({}^{+}\). Infrared (IR) (potassium bromide, cm\({}^{-1}\)): \(\
u_{\rm asym}\)(C\(\equiv\)N) 2268 (m), \(\
u_{\rm sym}\)(C\(\equiv\)N) 2152 (vs), \(\
u\)(C-O) 1252 (s), \(\
u\)(C=N) 1620 (vs), \(\
u\)(C-H) 3418 (m). \(\mu\) = 5.0 BM. \({}^{1}\)H nuclear magnetic resonance (NMR) (dimethyl sulfoxide-d\({}_{6}\), ppm): \(\delta\) -20.7 (H4), -29.8 (H5). E\({}_{\rm ox}\) = -0.085 V; E\({}_{\rm red}\) = -0.165 v; E\({}_{1/2}\) = -0.125 V. \(\Lambda_{\rm M}\) = 54 \(\mu\)S.  
MnL\({}^{3}\)(H\({}_{2}\)O)(ClO\({}_{4}\)) (**3**) was obtained by a procedure which has been already reported [17] using 1.00 g (1.99 mmol) of H\({}_{2}\)L\({}^{3}\), 0.72 g (1.99 mmol) of Mn(ClO\({}_{4}\))\({}_{2}\).6H\({}_{2}\)O and 0.16 (3.98 mmol) of NaOH. Experimental details are available in the Supplementary Materials section. Yield: 0.82 g (60%). Calculated Elemental Analysis for C\({}_{19}\)H\({}_{20}\)Br\({}_{2}\)ClMnN\({}_{2}\)O\({}_{9}\) (670.6): C, 34.0; H, 3.0; N, 4.2%. Found: C, 34.3; H, 3.4; N, 4.1%. MS ESI (_m/z_): 553 [MnL\({}^{3}\)]\({}^{+}\) IR (potassium bromide, cm\({}^{-1}\)): \(\
u_{\rm 3}\)(ClO\({}_{4}\)) 1121, \(\
u\)(C-O) 1294 (s), \(\
u\)(C=N) 1615 (vs), \(\
u\)(O-H) 3425 (m). \(\mu\) = 4.7 BM. E\({}_{\rm ox}\) = -0.034 V; E\({}_{\rm red}\) = -0.114 v; E\({}_{1/2}\) = -0.074 V. \(\Lambda_{\rm M}\) = 91 \(\mu\)S.  
Mn\({}_{2}\)L\({}^{4}\)(H\({}_{2}\)O)\({}_{2}\)(N(CN)\({}_{2}\))\({}_{2}\) (**5**) was obtained by the same procedure as **1**, using 0.15 g (0.41 mmol) of H\({}_{2}\)L\({}^{4}\), 0.11 g (0.41 mmol) of Mn(CH\({}_{3}\)COO)\({}_{2}\) and 0.04 g (0.41 mmol) of NaN(CN)\({}_{2}\). Experimental details are available in the Supplementary Materials section. Yield: 0.13 g (70%). Calculated Elemental Analysis for C\({}_{44}\)H\({}_{52}\)Mn\({}_{2}\)N\({}_{10}\)O\({}_{10}\) (990.8): C, 53.3; H, 5.3; N, 14.1. Found: C, 52.8; H, 5.1; N, 13.9%. MS ES (_m/z_): 423 [MnL\({}^{4}\)]\({}^{+}\); 490 [MnL\({}^{4}\)(C(CN)\({}_{2}\))]\({}^{+}\). IR (potassium bromide, cm\({}^{-1}\)): \(\
u_{\rm asym}\)(C\(\equiv\)N) 2260 (m), \(\
u_{\rm sym}\)(C\(\equiv\)N) 2147 (vs), \(\
u\)(C-O) 1252 (s), \(\
u\)(C=N) 1624 (vs), \(\
u\)(O-H) 3420 (m). \(\mu\) = 5.0 BM. \({}^{1}\)H NMR (dimethylsulfoxide-d\({}_{6}\), ppm): \(\delta\) -24.55 (H4), -15.81 (H5). E\({}_{\rm ox}\) = -0.116 V; E\({}_{\rm red}\) = -0.256 v; E\({}_{1/2}\) = -0.186 V. \(\Lambda_{\rm M}\) = 74 \(\mu\)S.  
MnL\({}^{4}\)(H\({}_{2}\)O)\({}_{2}\)(ClO\({}_{4}\)) (**6**) was obtained by the same procedure as **3**, using 0.6 g (1.62 mmol) of H\({}_{2}\)L\({}^{4}\), 0.59 g (1.62 mmol) of Mn(ClO\({}_{4}\))\({}_{2}\).6H\({}_{2}\)O and 0.13 g (3.24 mmol) of NaOH. Experimental details are available in the Supplementary Materials section. Yield: 0.71 g (82%). Calculated Elemental Analysis for C\({}_{21}\)H\({}_{28}\)ClMnN\({}_{2}\)O\({}_{10}\) (558.8): C, 45.1; H, 5.0; N, 5.0. Found: C, 45.4; H, 4.8; N, 5.1%. MS ES (_m/z_): 423 [MnL\({}^{4}\)]\({}^{+}\). IR (potassium bromide, cm\({}^{-1}\)): \(\
u_{\rm 3}\)(ClO\({}_{4}\)) 1122 (vs), \(\
u\)(C-O) 1307 (s), \(\
u\)(C=N) 1612 (vs), \(\
u\)(O-H) 3420 (m). \(\mu\) = 5.0 BM.