Employment of methyl 2-pyridyl ketone oxime in manganese non-carboxylate chemistry: MnII2MnIV and MnII2MnIII6 complexes

• DOI: 10.1039/b813828a
• Publication Date: 2009-01-09T13:30:09Z
• Authors: Constantinos C. S...; Theocharis C. Sta...; Harikleia Sartzi; Olivier Roubeau; Anastasios J. Tas...; Vassilios Nastopo...; Simon J. Teat; George Christou; Spyros P. Perlepes
• Keywords: Carboxylate

The employment of the anion methyl 2-pyridyl ketone oxime (mpko−) as a tridentate chelating/bridging ligand in manganese chemistry is described. inorganic (Br−, ClO4−) used reaction affects identity product. MnBr2 and one equivalent mpkoH presence base affords [Mn3(OMe)2(mpko)4Br2] (3), which mixed-valence (2MnII, MnIV). central MnIV atom each two, crystallographically independent, centrosymmetric molecules coordinated by four oximate oxygen atoms belonging to η1:η1:η1:μ mpko− ligands, two η1:μ MeO− groups, while six coordination at terminal MnII completed nitrogen 'chelating' part Br− ion. have trigonal prismatic geometry. Mn(ClO4)2·6H2O, OH− (1:2:1) MeOH gives [Mn8O4(OMe)(mpko)9(mpkoH)](ClO4)4 (4), also 6MnIII) possesses novel [Mn8(μ3-O)4(μ-OMe)(μ-OR″)2]11+ core. latter U-shaped sequence fused {MnIIMnIII2(μ3-O)}6+ triangular units, with MnIII-MnIII edge being shared between triangles. Variable-temperature, solid-state dc ac magnetic susceptibility studies were carried out on complexes 3 4. data for 5.0–300 K range been fit model J values, revealing weak ferromagnetic MnII⋯MnIV (J = +3.4 cm−1) MnII⋯MnII (J′ +0.3 exchange interactions. Fitting magnetization vs. H/T matrix diagonalization including only axial anisotropy (ZFS, D) gave ground state spin (S) D values S 13/2, +0.17 cm−1 3, −0.09 combined work demonstrates usefulness preparation interesting Mn clusters, without requiring co-presence carboxylate ligands.