Four-step iron(ii) spin state cascade driven by antagonistic solid state interactions

• Published in: Chemical science (Cambridge) Vol. 8; no. 1; pp. 701 - 707
• Main Authors: Sciortino, Natasha F, Zenere, Katrina A, Corrigan, Maggie E, Halder, Gregory J, Chastanet, Guillaume, Létard, Jean-François, Kepert, Cameron J, Neville, Suzanne M
• Format: Journal Article
• Language: English
• Published: England The Royal Society of Chemistry 01.01.2017; Royal Society of Chemistry
• Subjects: Cascades; Chemical Sciences; Chemistry; Coordination chemistry; Crossovers; Flexibility; Lattices; Material chemistry; Networks; Patterning; Stabilization; Topology
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c6sc03114e

A four-stepped cascade of Fe(ii) high spin (HS) to low spin (LS) states is demonstrated in a family of 2-D Hofmann materials, [Fe (saltrz) (M (CN) ) ]·8(H O) (M = Pd ( ), Pt ( ); saltrz = ( )-2-(((4 -1,2,4-triazol-4-yl)imino)methyl)phenol). Alongside the fully HS and LS Fe(ii) states, fractional spin state stabilization occurs at HS/LS values of 5/6, 2/3, and 1/6. This unconventional spin state periodicity is driven by the presence of multiple spin crossover (SCO) active Fe(ii) sites which are in subtly distinct environments driven by a network of antagonistic host-host and host-guest interactions. Alternating long- and short-range magnetostructural ordering is achieved over the five distinct spin state ratios HS LS , HS LS , HS LS , HS LS , and HS LS owing to the flexibility of this 2-D interdigitated lattice topology interconnected by intermolecular interactions. A distinct wave-like spin state patterning is structurally evidenced for each intermediate phase.