Spin crossover in a mononuclear compound [Fe(EPPA)(bpym)]-(ClO4)2 (EPPA = N-(2-aminoethyl)-N-(3-aminopropyl)-2-(aminomethyl)pyridine, bpym-2,2′-bipyrimidine):: Synthesis, structure, and magnetic properties

The synthesis, magnetic properties and single crystal study of a new spin crossover compound [Fe(EPPA)(bpym)](ClO4)(2) with EPPA = N-(2-aminoethyl)-N-(3-,aminopropyl)-2-(aminomethyl)pyridine, bpym = 2,2'-bipyrimidine are reported. Variable-temperature magnetic susceptibility data collected in the temperature range 10-294 K reveal the occurrence of a relatively cooperative spin transition with T-1/2 = 108 K. The crystal structure of [Fe(EPPA)(bpym)](ClO4)(2) was determined by single-crystal X-ray diffraction method. The structure of the complex consists of mononuclear [Fe(EPPA)(bpym)](ClO4)(2) units. The potentially bis-bidentate bpym ligand acting as a bidentate one, is coordinated to iron(II) in cis-position by two nitrogen atoms. The four remaining positions in the pseudooctahedral [FeN6] core are occupied by one pyridinic and three aliphatic nitrogens of the EPPA ligand. The network of cooperative links in the crystal lattice is represented by H-bonding and pi stacking interactions. (c) 2006 Elsevier B.V. All rights reserved.