Mn(III) Chain Coordination Polymers assembled by Salicylidene–2–ethanolamine Schiff Base Ligands: Synthesis, Crystal Structures and HFEPR Study

A family of eight polymeric manganese (III) complexes with the general formula Mn(HL1,2)2X, (H2L1 = 2[(2–hydroxyethyl)iminomethyl]phenol, H2L2 = 2[(2–hydroxyethyl)iminomethyl]–6–methoxy–phenol) while X = Cl (1, 5), Br (2, 6), I (3, 7), NCS (4, 8) for H2L1 and H2L2, respectively were obtained using “the direct synthesis” approach, i.e., the oxidative dissolution of the manganese powder in the presence of a Schiff base (SB), an ammonium salt and oxygen of the air. Single crystal X–ray diffraction studies for the new complexes 2, 3, 4 and 8 were compared with the previously reported crystallographic data for 1 and 7, showing that all complexes possess 1D polymeric structure. The main structural units in 1–7 are cationic chains [Mn(HL1,2)2]nn+ and anions X- linked together via electrostatic interactions and hydrogen bonds, while the complex 8 consists of polymeric chains of neutral [Mn(HL2)2(NCS)]n units. The SB ligands are mono–deprotonated as HL-, and coordinated by the metal atoms in a tridentate chelate–b...