Syntheses and characterization of binuclear manganese(III,IV) and -(IV,IV) complexes with ligands related to tris(2-pyridylmethyl)amine

A Facile Route to Difunctionalized Monosubstituted Octasilsesquioxanes

“…The observed range of values are reported. Structural data for Mn III /Mn III (bispicen) 2 ,16a,16q Mn 2 III /Mn III (bispyzen) 2 ,16a Mn 2 III /Mn III (6‐Me 2 tmpa) 2 ,16a Mn 2 IV /Mn IV (bispicen) 2 ,16b Mn 2 IV /Mn IV (phen) 2 ,16c Mn 2 IV /Mn IV (6‐MeL 1 ) 2 16d. Ligands: bispicen= N , N ′‐bis(2‐pyridylmethyl)‐1,2‐ethanediamine, bispyzen= N , N ′‐bis(pyrazin‐2‐ylmethyl)ethane‐1,2‐diamine, 6‐Me 2 tmpa= N , N ‐bis[(6‐methylpyridin‐2‐yl)methyl]‐ N ‐(pyridin‐2‐ylmethyl)amine, phen=1,10‐phenanthroline, 6‐MeL 1 = N ‐[(6‐methylpyridin‐2‐yl)methyl]‐ N , N ‐bis(pyridin‐2‐ylmethyl)amine.…”

“…Also in this case, complexes with zero charge, formally formed by Mn II ions, have not yet been synthesized. In all the known complexes with formula [MnO(L 4 )] 2 2+/4+ the manganese ions were found to be antiferromagnetically coupled; the J values ranged from 170 to 300 cm −1 according to the nature of the L 4 ligand and to the oxidation state 16a–16d, 21…”

Crystal Structure and Characterization of a New Mixed‐valence Manganese(III/IV) Complex: [Mn2(cyclen)2(μ‐O)2](ClO4)3·4H2O

“…These bands were assigned to the charge-transfer transitions of Mn(IV) center from the oxo groups to the metal dπ* orbits. 8 Interestingly, these bands are also observed in some metalloenzymes, such as manganese catalases and manganese ribonucleotide reductases extracted from organisms. 13 Cyclic voltammetry Figure 3 shows the cyclic voltammetry curve of complex 1 in acetonitrile, revealing a quasi-reversible redox wave with E a ＝0.908 V, E c ＝0.746 V and E 1/2 ＝0.827 V vs. the SCE.…”

“…This has been discussed in detail for [(pmea)Mn(µ-O) 2 Mn(pmea)] 3＋ which also has a crystallographic inversion center in the middle of the dimmer. 8 As shown in Table 2 …”

“…These physical properties were modeled well by the mixed-valence complexes [L 2 Mn(µ-O) 2 MnL 2 ] 3＋ (2: L＝bpy＝2,2'-bipyridine; 3: L＝phen＝1,10-phenanthroline) 5,6 and [LMn(µ-O) 2 MnL] 3 ＋ (4: L ＝ tren ＝ tris(2-aminoethyl)amine; 5: L＝pmea＝[2-(2-pyridyl)ethyl]bis(2-pyridylmethyl)amine). 7,8 These complexes have been characterized by single-crystal X-ray diffraction technique, and only in complexes 2 and 4 the Mn(III) and Mn(IV) ions can be clearly distinguished.…”