Predictable adjustment of spin crossover temperature in solutions of iron(iii) complexes functionalized with alkyl-urea tails

Abstract

A new series of amphiphilic alkylurea functionalised iron(iii) sal2trien complexes were prepared by substitution of phenolic ligand site with OCnH2n–NHC(O)NHCmH2m+1 tails (n = 5, 9, m = 4, 12, 14, 16).

Engineering On‐Surface Spin Crossover: Spin‐State Switching in a Self‐Assembled Film of Vacuum‐Sublimable Functional Molecule

“…Importantly, functionalization of the parent system with the dodecyl chain also resulted in a 50 K increase in the T 1/2 value relative to its parent complex. This clearly elucidates the role of the chemical substituent in tuning SCO, in line with the literature reports detailing alkyl chain tuning of SCO characteristics . The parent [Fe(H 2 B(pz) 2 ) 2 (bpy)] complex was reported to grow on amorphous surfaces in a Volmer–Weber mode (i.e., the atoms of the film are more strongly coupled with each other than with the substrate) by crystallites formation, whereas functionalization of the [Fe(H 2 B(pz) 2 ) 2 (bpy)] head with the C 12 chain imposed a preferential stacking direction and facilitated vertically ordered growth on the surface beneficial in terms of fabricating multilayer vertical SCO junctions .…”

Spin-crossover and high-spin iron(ii) complexes as chemical shift19F magnetic resonance thermometers

“…This temperature dependence of the spectra is indicative of a thermally-induced spin state transition. 22 , 33 Indeed, approximating a metal complex of O h symmetry, the intensity of the MLCT band is directly correlated to the number of electrons in t 2g orbitals. 32c , d As such, moving from low-spin Fe II (t62g) to high-spin Fe II (t42ge2g) with increasing temperature results in a weaker absorption.…”

Correlations between ligand field Δo, spin crossover T1/2 and redox potential Epa in a family of five dinuclear helicates

“…In the solid state, crystal packing, co-crystallised solvent and intermolecular cooperativity can obscure the electronic modifications imposed by variation of the ligand. In contrast, solution SCO opens the door to investigating the electronic effect arising from ligand modification, [37][38][39][40] including from a 'tail', [41][42][43] as well as the effects of solvent polarity, 44 concentration 41 and pH. 45 1,2,4-Triazole ligands, which can be substituted at the C 3 , N 4 and/or C 5 positions on the triazole ring (Figure 2), provide an appropriate ligand field strength for generating Fe(II) spin crossover materials.…”