Synthesis and characterization of a ferric complex of the tripodal ligand tris(2-benzimidazolylmethyl)amine—a superoxide dismutase mimic

Synthesis, Structure and Spectral, and Electrochemical Properties of New Mononuclear Ruthenium(III) Complexes of Tris[(benzimidazol‐2‐yl)methyl]amine: Role of Steric Hindrance in Tuning the Catalytic Oxidation Activity

“…The bond angles around the Ru center (81.01-99.02; 162.09-179.52°) deviate considerably from the ideal values of 90°and 180°and the N4-Ru-N6 bond angle of 162.1(2)°i ndicates that the primary distortion involves the diagonally opposite bzim nitrogen atoms (N4, N6), which are bent away from an axis normal to the RuN1N2Cl1Cl2 plane ( Figure 2). + [19,20] [20,24,25,26] Further, as the Ru III center is not capable of back-bonding the metal-ligand bond lengths are determined primarily by the σ basicity of the nitrogen atoms. [27] Thus Ru-N bzim bonds in 1 are shorter than the Ru-N py bonds (2.073-2.087 Å) [12,14] in the analogous complex [Ru(tpa)Cl 2 ]ClO 4 (3) and other ruthenium complexes.…”

“…In this study we probe the effect of replacing the π-backbonding py rings in [Ru(tpa) + , where ntb is tris(benzimidazol-2-ylmethyl)amine and mntb is tris(N-methylbenzimidazol-2-ylmethyl)amine (Scheme 1), on the molecular structure and electronic and chemical properties and catalytic efficiency of the complexes. In fact, the copper(II) [18] and iron(III) [19,20] complexes of the ntb ligand have been isolated and studied in detail and their structures observed and the values of redox potentials measured are a clear demonstration of the predominance of steric factors over electronic contributions of the ligand. Also, Haga et al [16] have found that the complexes with bzim skeletons can catalyze the oxidation of organic compounds.…”

Synthesis and Crystal Structures of Two Dinuclear Iron(III) Complexes with Tripodal Ligands

“…These metrical parameters fall within the ranges reported for other µ-oxo-µ-carboxylato-diiron(III) complexes and are similar to those found for the binuclear sites of several iron-oxo proteins. [9][10][11][12][15][16][17] The coordination environments of the two iron atoms in each complex are different. (2)-N(7) (benzimidazole) (0.221 nm) are markedly longer than the other corresponding Fe-N bond lengths.…”

“…In an attempt to model the structure and physical properties of these biological systems, a large number of oxo bridged diiron complexes have been prepared and characterized. [9][10][11][12][13][14] Tris(2-pyridylmethyl)amine (TPA) and tris(2-benzimidazolylmethyl)amine (NTB) are versatile tripodal potentially tetradentate ligands containing pyridine or benzimidazole groups and a number of their complexes are known at present. [15][16][17][18][19][20] In this paper, we have investigated the iron(III) coordination compounds of TPA and NTB, which show potential coordination environments in biological system.…”

NMR Reveals That a Highly Reactive Nonheme FeIV=O Complex Retains Its Six‐Coordinate Geometry and S=1 State in Solution

“…The outer shell is best fit with Cs catterers at 3.05 and 3.26 ,w hicha re associated with carbon atoms on the benzimidazole rings, as observed in the crystal structureso firon-benzimidazole complexes. [10,[15][16][17] The average FeÀN/O distance of 2.06 is within experimental error essentially the same as the values predicted by DFT for as ixcoordinate 1 in an S = 1s tate (2.03 )a nd for an S = 2t rigonalbipyramidal 1 (2.04 ), but much smaller than the 2.14 distance calculated for its S = 2s ix-coordinate counterpart (Table S5), [12] which excludes the latter as ap roper description for 1 at 10 K.…”