Synthesis, Structure, and Catalytic Activity of New μ‐Oxo‐Bridged Diiron(III) Complexes

Abstract

The preparation and characterisation of two dinuclear iron(III) complexes with tripodal ligands 1,3-bis(2Ј-pyridylimino)isoindoline (indH) are presented. The µ-oxo-bridged di- (2)

Redox properties of cobalt(II) complexes with isoindoline-based ligands

“…Terpyridines [1], bis-(N-arylimino)isoindolines (BAI, or indH) [2], and tripyrrins (Trpy) [3] are built-up on rigid p-conjugated frameworks that favor meridional coordination. In addition, with respect to the isoindoline-based ligands, two tridentate binding modes have been demonstrated: in some cases, the ligand is neutral and bears an exocyclic amine function (Scheme 1, forms A and C) [4][5][6][7][8][9], whereas in the majority of the known complexes the isoindoline nitrogen of form B (Scheme 1) is deprotonated resulting a monoanionic ligand with two imine functions [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. BAIs form stable complexes with cobalt that exhibit remarkable reactivities.…”

“…We have recently published new manganese(II) [6][7][8]28], iron(II) and (III) [15,19,27], and nickel(II) [28] complexes with the isoindoline-based ligands shown in Scheme 1. In those complexes, it was possible to control the redox potential of the metal center by varying the aryl substituent on the bis-iminoisoindoline moiety.…”

Synthesis, structure and spectral properties of a novel stable homoleptic iron(II) complex of 1,3-bis(2′-pyridylimino)isoindoline, Fe(ind)2

“…All coordination sites of the metal are occupied by the tridentate 1,3-bis(2 0 -pyridylimino)isoindolinato ligands. The Fe-N bond lengths are consistent with a high-spin Fe(II) ion, lying within the range 2.068-2.271 Å , and are little longer than those obtained for Fe(III) complexes of the ind ligand [9,18]. The Fe-N distances are longer in high-spin iron(II) complexes than in low-spin ones [19].…”

“…The ligands are capable of occupying three sites about a metal ion and forming either 1:1 or 2:1 (ligand: metal) complexes depending on the coordination number and geometry of the metal ion. We have just reported the preparation and crystal structure of a loxo-bridged diiron(III) complex, (Fe(ind)Cl) 2 O, with tripodal ligand 1,3-bis(2 0 -pyridylimino)isoindoline (1, indH) [9]. (2 0 -pyridylimino)isoindoline in acetone [10].…”

Synthesis, structure and catalase mimics of novel homoleptic manganese(II) complexes of 1,3-bis(2′-pyridylimino)isoindoline, Mn(4R-ind)2 (R=H, Me)

“…So considerable efforts were made in order to obtain non-toxic, low molecular weight biomimetic molecules, which are able to catalyze the dismutation of superoxide anion and/or destroy the forming hydrogen peroxide. A variety of low molecular weight complexes of transition metals (Cu, Mn) were prepared and studied as structural and/or functional models for catalases [7][8][9][10][11][12][13].1,3-Bis(2 0 -pyridilimino)isoindolines have been shown to function as neutral, nondeprotonated and also as uninegative chelating ligands capable of complexing a large variety of transition metal ions [14][15][16][17][18][19]. The ligands are capable of occupying three coplanar sites around a metal ion forming either 1:1 or 2:1 (ligand:metal) complexes depending on the coordination number and geometry of the metal ion.…”