Post-synthetic anion exchange in iron(ii) 1,2,4-triazole based spin crossover materials via mechanochemistry

Abstract

A simple solvent-free method for post-synthetic exchange of anions in an iron(ii) spin crossover material is described.

Mechanochemical Processing of Highly Conducting Organic/Inorganic Composites Exhibiting Spin Crossover–Induced Memory Effect in Their Transport Properties

“…An small amount of the SCO component appears to be oxidized during the milling protocol, resulting in the appearance of a small paramagnetic impurity which does not participate in the SCO hysteresis cycle (Figure S4, Supporting Information), as already observed for other SCO materials under milling treatment. [ 44–46 ]…”

Complete and Versatile Post‐Synthetic Modification on Iron‐Triazole Spin Crossover Complexes: A Relevant Material Elaboration Method

“…It is not obvious that such positive results could have been obtained from all the other iron complexes ([Fe(NH 2 trz) 3 ]X 2 where X=NO 3 − , BF 4 − , Cl − ⋅⋅⋅). In case the reaction could not be carried out from the iron complex with the desired counter ion, an alternative to be considered is to carry out the reaction with the tosylate iron complex and then through metathesis, to exchange the anion as reported before [45] . The diversity of new materials that could be obtained from the iron complex 1 and 2 , and the stability of the latter under different experimental conditions, make these results very encouraging.…”

“…In case the reaction could not be carried out from the iron complex with the desired counter ion, an alternative to be considered is to carry out the reaction with the tosylate iron complex and then through metathesis, to exchange the anion as reported before. [45] The diversity of new materials that could be obtained from the iron complex 1 and 2, and the stability of the latter under different experimental conditions, make these results very encouraging. The PSM methodology can probably be applied to hybrid materials combining 4-amino-1,2,4-triazole ligands with other modified triazole ligands.…”

“…To the best of our knowledge, few examples using this methodology for SCO materials are described in the literature. They consist of post-functionalization of 3D Hofmann clathrate MOF, [41,42] a dinuclear iron(III) complex, [43] a Fe II [M IV (CN) 8 ] 4 À (M=Mo, Nb) cyanido-Bridged Framework, [44] 1D polymeric iron-triazole complexes [45][46][47][48][49][50] and of iron poly(pyrazolyl)borate complexes. [51,52] In 2001, Saf et al [49] published the synthesis of a spin crossover material, for which the last step of the synthesis corresponds to the polymerization of the methacrylate substituent present on the triazole ligand.…”

“…To the best of our knowledge, few examples using this methodology for SCO materials are described in the literature. They consist of post‐functionalization of 3D Hofmann clathrate MOF, [41,42] a dinuclear iron(III) complex, [43] a Fe II [M IV (CN) 8 ] 4 − (M=Mo, Nb) cyanido‐Bridged Framework, [44] 1D polymeric iron‐triazole complexes [45–50] and of iron poly(pyrazolyl)borate complexes [51,52] …”