Syntheses and EPR spectral studies of manganese(II) complexes derived from pyridine-2-carbaldehyde based N(4)-substituted thiosemicarbazones: Crystal structure of one complex

Five manganese(II) complexes {[MnL12]·H2O·EtOH (1), [Mn(L1)(HL1)]OAc (2), [MnL22]·3H2O (3), [MnL32]·3H2O (4) and [Mn(HL3)2](SCN)2 · MeOH (5)} of three NNS donor N(4)-substituted thiosemicarbazone ligands {pyridine-2-carbaldehyde N(4)-p-methoxyphenyl thiosemicarbazone [HL1], pyridine-2-carbaldehyde N(4)-2-phenethyl thiosemicarbazone [HL2] and pyridine-2-carbaldehyde N(4)-methyl, N(4)-phenyl thiosemicarbazone [HL3]} were synthesized and physico-chemically characterized. Compound 1 crystallized as [MnL12]·H2O and its structure has been determined by X-ray diffraction studies. It is found to have a distorted octahedral geometry. EPR spectra in DMF solutions at 77 K show hyperfine sextets with low intensity forbidden lines lying between each of the two main hyperfine lines.

Graphical abstractFive manganese(II) complexes {[MnL12]·H2O·EtOH, [Mn(L1)(HL1)]OAc, [MnL12]·3H2O, [MnL12]·3H2O and [Mn(HL3)2](SCN)2 · MeOH} of three NNS donor N(4)-substituted thiosemicarbazone ligands {pyridine-2-carbaldehyde N(4)-p-methoxyphenyl thiosemicarbazone [HL1], pyridine-2-carbaldehyde N(4)-2-phenethylthiosemicarbazone [HL2] and pyridine-2-carbaldehyde N(4)-methyl, N(4)-phenyl thiosemicarbazone [HL3]} were synthesized and physico-chemically characterized. The crystal structure of the compound [MnL12]·H2O has been determined by X-ray diffraction studies. It is found to have a distorted octahedral geometry. EPR spectra in DMF solutions at 77 K show hyperfine sextets with low intensity forbidden lines lying between each of the two main hyperfine lines.Figure optionsDownload full-size imageDownload as PowerPoint slide