Mixed-valence {FeII2FeIII4} hexanuclear complexes with thermally induced Fe(iii) spin-crossover behavior. Issue 34 (12th August 2022) - Jia, Shuwen
Abstract : Cyano-bridged mixed-valence {Fe6 } hexanuclear complexes {[Tp 4-Me Fe II (CN)3 ]2 [Fe III (Tpa)]2 [Fe III (OR)(Tpa)]2 }·6ClO4 (R = OM, OEt, OH) with Fe 3+ spin-crossover behavior. Abstract : Cyano-bridged mixed-valence {Fe6 } hexanuclear complexes {[Tp 4-Me Fe II (CN)3 ]2 [Fe III (Tpa)]2 [Fe III (OR)(Tpa)]2 }·6ClO4 · S (Tp 4-Me = tri(4-methyl-pyrazol-1-yl)borate, Tpa = tris(2-pyridylmethyl)amine; R = –CH3, S = 8MeOH 1, R = –C2 H5, S = 6EtOH 2 ) have been obtained by building the units of [Tp 4-Me Fe(CN)3 ] − and [Fe(Tpa)] 2+ in methanol and ethanol, respectively. Complex 1 exhibited single-crystal-to-single-crystal (SCSC) transformation to give {[Tp 4-Me Fe II (CN)3 ]2 [Fe III (Tpa)]2 [Fe III (OH)(Tpa)]2 }·6ClO4 ·8H2 O (3 ) in water. Detailed analysis of the coordination environment of the Fe III centers on the square lattice and magnetic susceptibility measurements of all the complexes confirmed their Fe 3+ spin-crossover (SCO) properties ( T 1/2 = 178 K, 1 ; 185 K, 2 ; 208 K, 3 ).