Synthesis and characterisation of manganese(III) unsymmetrical Schiff-base complexes: a unique example of a cocrystallised manganese(III) unsymmetrical Schiff-base complex, and a symmetric Schiff-base complex arising from rearrangement of the former

Abstract

Some manganese(i1i) complexes with unsymmetrical Schiff bases have been prepared and characterised. The ligands were prepared by condensation of 7-amino-4-methyl-5-azahept-3-en-2-one with salicylaldehyde, 2hydroxyacetophenone orsu bstituted salicylaldehydes (5-c hloro, 5-methoxy, 3-ethoxy or 3.5-dibromo). On reaction with manganese(l1) perchlorate in air, manganese( 111) Schiffbase complexes are obtained. The crystal structures of two of these have been determined, one being cocrystallised with [{ Mn(salen) ( H,O)},] [CIO,], containing the symmetrical salen ligand [N,N'-ethane-l,2-diylbis-(salicylideneiminate)]. Unlike the dimeric structures previously found for similar complexes, the two

Activation of a water molecule using a mononuclear Mn complex: from Mn-aquo, to Mn-hydroxo, to Mn-oxyl via charge compensation

“…This type of second sphere interaction has already been observed for Mn(III)-aquo complexes. 50,51 The formation of the water coordinated mononuclear complex in the presence of water indicates the higher affinity of water for manganese compared to acetonitrile.…”

Novel peroxidase mimics: μ-Aqua manganese–Schiff base dimers

“…The co-crystallisation phenomenon is rather abundant in manganese coordination chemistry [25][26][27], and it points out the ability of these complexes to evolve into a different structure in solution, driven by slight variations in the media. In this way, we have found plentiful of cases of replacement of labile ligands [9,16,17,[28][29][30] from the manganese coordination sphere.…”

An Interesting Six-Connected 3D Nanowater Framework Constructed from Turbine-Type (H2O)18 Clusters Based on a Mn(III) Complex

“…Due to the Jahn-Teller effect of Mn(III), the Mn ion lies in the center of an elongated octahedron. In the equatorial plane defined by the O1, N1, N2, and O3 atoms from the vanen ligand, the bond distances of Mn1-O1, Mn1-O3, Mn1-N2, and Mn1-N1 are 1.873( 3 21 As depicted in Figure 1b, a novel turbine-type (H 2 O) 18 cluster is assembled by the free lattice water molecules (six O6, six O7, six O8) through hydrogen bonding interactions. The (H 2 O) 18 cluster consists of a center hexameric cluster with the chair configuration (see Figure S1 in the Supporting Information) and six dangling dimeric water molecules.…”