Syntheses, EPR spectral studies and crystal structures of manganese(II) complexes of neutral N,N donor bidentate Schiff bases and azide/thiocyanate as coligand

摘要

Four manganese(II) complexes Mn_2(paa)_2(N _3)_4 (1), [Mn(paa)_2(NCS)_2] ·~3/_2H_2O (2), Mn(papea) _2(NCS)_2 (3), [Mn(dpka)_2(NCS) _2]·~1/_2H_2O (4) of three neutral N,N donor bidentate Schiff bases were synthesized and physico-chemically characterized by means of partial elemental analyses, electronic, infrared and EPR spectral studies. Compounds 3 and 4 were obtained as single crystals suitable for X-ray diffraction. Compound 4 recrystallized as Mn(dpka) _2(NCS)_2. Both the compounds crystallized in the monoclinic space groups P2_1 for 3 and C2/c for 4. Manganese(II) is found to be in a distorted octahedral geometry in both the monomeric complexes with thiocyanate anion as a terminal ligand coordinating through the nitrogen atom. 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 and the zero field splitting parameters (D and E) were calculated.