Diverse Magnetic Properties of Two New Binuclear Complexes Affected by [FeN6] Octahedral Distortion: Two-Step Spin Crossover versus Antiferromagnetic Interactions

Polymetallic complexes with covalently bridged metal centers that interact magnetically are important in the molecular magnetism field, binuclear compounds receiving special attention because they represent simplest type of multinuclear species centers. Herein, we report synthesis and properties two new FeII complexes, namely, {[Fe(abpt-TPE)(NCS)2]2(bpym)}·2MeOH·2MeCN (1) {[Fe(abpt-TPE)(NCS)2]2(bpym)}·2CH2Cl2 (2) (bpym = 2,2′-bipyrimidine). The crystal structure is analyzed at different temperatures, its by variable-temperature magnetic susceptibility fluorescence emission spectroscopy tests. Variable-temperature measurements show types behavior. Complex 1 exhibits two-step spin transition behavior an intermediate state near 150 K (Tc1 191 K, Tc2 111 K); undergoes [LS–LS] ↔ [LS–HS] [HS–HS] during thermal induction. On other hand, complex 2 intramolecular antiferromagnetic coupling, J −0.47 cm−1. analysis correlations between structural characteristics behaviors for revealed shown attributable to degrees [FeN6] octahedral distortion caused lattice solvents, ligand strain stacking.