Structural effects on the magnetic properties of ferric complexes in molecular materials or a lamellar CdPS3 host matrix

Abstract

The electronic properties of cationic ferric complexes were investigated in molecular materials and in a negatively charged lamellar host matrix. Two cations, [Fe^III(R-Sal₂Trien)]⁺ [where H₂-R-Sal₂Trien is the hexadentate ligand derived from triethylenetetramine and R-substituted salicylaldehydes (R = 3,5-Cl₂ or 5-OMe)], were first assembled with different anions (NO₃⁻, ClO₄⁻, PF₆⁻ or BPh₄⁻). The obtained compounds exhibit various magnetic behaviours. S = 5/2 high-spin species, S = 1/2 low-spin species and S = 5/2 ↔ S = 1/2 spin-crossover complexes were identified from variable-temperature SQUID measurements and, in the case of the two cations associated to ClO₄⁻ and PF₆⁻, were confirmed by their X-ray crystal structures at 293 K. When the ferric cations are intercalated within the van der Waals gap of the lamellar CdPS₃ host phase, their structural and electronic characteristics appear to be strongly affected. The incomplete spin crossover observed for [Fe(5-OMe-Sal₂Trien)]_0.26Cd_0.87PS₃˙nH₂O and the low-spin behaviour of [Fe(3,5-Cl₂-Sal₂Trien)]_0.22Cd_0.89PS₃ can be partly attributed to a different arrangement of the cationic species in the interlamellar space.