Spin-Transition in FeIIN6 Complexes

This book has been organized into four chapters. Introductory Chapter 1 presents a brief description of spin-state transition phenomenon in FeIIN6 complexes, followed by the effect of counter-anions on spin-crossover behavior. Chapter 2 describes the synthesis of three new FeIIN6 complexes with non-planar tridentate ligand (L4) with different counter-anions (CF3SO3-, PF6-, and BPh4-) in order to study the effect of counter-anions on spin-crossover system [FeII(L4)2]2+. Chapter 3 describes the synthesis and detailed characterization of three bis-ligand complexes of iron(II) with a noval non-planar tridentate ligand L5 (see below) having pyridine, pyrazole and imidazole donor sites with different counter-anions (BF4-, CF3SO3-, and PF6-). The primary concern of this chapter is to study and compare the effect of different counter-anions on [FeII(L5)2]2+ system. In Chapter 4 three new ligands MeL4, MeL5, and ClL5 have been considered. The ligands MeL4 and MeL5 were chosen to pinpoint the predominance of steric effect and ClL5 was considered to pinpoint the predominance of electronic effect to fine-tune the spin-state behavior of the parent ligands L4 and L5 towards iron(II).