Manganese(II) complexes based on sterically hindered {N,O,O} tridentate Schiff bases: synthesis, structures, and properties

Manganese(II) complexes (DMSO){(DMSO)2bis[5,7-di-tert-butyl-2-(2-hydroxyphenolato)-1,3-benzoxazol-4-ol]}manganese(II) (Ia) and (DMSO)2{bis[5,7-di-tert-butyl-2-(2-hydroxyphenolato)-5-nitro-1,3-benzoxazol-4-ol]}manganese(II) (Ib) are synthesized from the tridentate sterically hindered Schiff bases: condensation products of 4,6-di-tert-butyl-2-aminophenol with salicylaldehyde derivatives N-(3,5-di-tert-butyl-2-oxyphenyl)salicylaldimine and N-(3,5-di-tert-butyl-2-oxyphenyl-5-nitro)salicylaldimine. The structures and compositions of the synthesized metal chelates are characterized by C, H, and N elemental analysis, IR spectroscopy, and magnetochemical measurement data. The EPR data in DMF and toluene are presented for complex Ia. The molecular structures of complexes Ia and Ib are proved by X-ray diffraction (XRD) results (CIF files CCDC nos. 2325776 (Ia) and 2325777 (Ib), respectively). In both complexes, the manganese ion exists in the octahedral {N2O4} ligand environment in which the coordination occurs due to two nitrogen atoms of the benzoxazole cycle and two oxygen atoms of the o-hydroxyphenol group and the apical positions are occupied by the oxygen atoms of two DMSO molecules.