Abstract
The biomimetic compound [PPN]2[Fe(η2-NO3)4] (1) was synthesized by the reaction of ferrous chloride with AgNO3 and [PPN][NO3]. The fitting results of magnetic measurements by SQUID elucidated that the negative zero field splitting led to the ms = ± 2 ground state, resulting in the effective magnetic moment (μeff) increasing from 5.71 μB at 300K to 7.02 μB at 13K. The weak intermolecular antiferromagnetic interaction through terminal nitrate between complex 1 pair, observed from by the paired arrangement of crystallographical lattice (intermolecular O…O distance (6.01 Å)), led to the effective magnetic moment (μeff) decreasing from 7.02μB at 12K to 5.56μB at 2K. In addition, complex 1 exposed to NO produces a typical {Fe(NO)}7 MNIC [PPN]2[(NO3)3Fe(NO)(η2-NO3)] (2), identified by the EPR and SQUID. The reduction of complex 2 by KC8 and following exposure to NO lead to [PPN][(NO3)2Fe(NO)2] (3) (50%) and [(NO3) (ONO) Fe (NO) 2] (4) (50%). The ligand substitution reaction between complex 1 and [PPN][NO2] shows that the electron donating ability of [NO2]- is stronger than [NO3]-.