We report the multistep synthesis of a thiadiazole based ligand (LOMe-Nap) with a methoxy substituent in the six-position of the naphthalene ring, along with the corresponding iron(II) [FeII(LOMe-Nap)2(NCE)2] 1–3 (E = S, Se, and BH3) complexes. We also report the synthesis of the [FeII(LNap)2(NCBH3)2] (4) complex with the previously reported LNap ligand. The complexes obtained were characterized by single crystal X-ray crystallography and SQUID magnetometry in all four cases (1–4). Complex 1 shows a weak thermally induced excited spin state trapping (TIESST) effect up to about 60 K. The effects of the methoxy ligand substituent in altering the noncovalent intramolecular π–π interaction are discussed, as well as the tuning of the switching temperature (T1/2) by the choice of NCE. The S < Se < BH3 series is established in both families of compounds. 

Effect of Methoxy Ligand-Substituent and NCE Coligands in Tuning T1/2 of Coordinatively Elastic Fe(II) Spin Crossover Complexes

Supramolecular architectures, which are formed through the combination of inorganic metal cations and organic ligands by self-assembly, are one of the techniques in modern chemical science. This kind of multi-nuclear system in various dimensionalities can be implemented in various applications such as sensing, storage/cargo, display and molecular switching. Iron(II) mediated spin-crossover (SCO) supramolecular architectures with Schiff bases have attracted the attention of many investigators due to their structural novelty as well as their potential application possibilities. In this paper, we review a number of supramolecular SCO architectures of iron(II) with Schiff base ligands exhibiting varying geometrical possibilities. The structural and SCO behavior of these complexes are also discussed in detail.

https://www.mdpi.com/1420-3049/28/3/1012/pdf?version=1674123769

Iron(II) Mediated Supramolecular Architectures with Schiff Bases and Their Spin-Crossover Properties

Temperature dependent X-ray photoemission spectroscopy (XPS) has been employed to examine the Fe 2p and N 1s core levels of the studied Fe(II) spin crossover (SCO) complexes of interest, namely:...

Surface stabilisation of the high-spin state of Fe(II) spin-crossover complexes

A two-dimensional grid-like coordination polymer, [Fe(NCBH3)2(Py2ttz)2]·4CHCl3 (1·4CHCl3, Py2ttz = 2,5-di(pyridin-4-yl)thiazolo[5,4-d]thiazole), showed one-step complete spin crossover with unexpectedly large hysteresis loop of 64 K wide and temperature-induced excited spin-state trapping effect below 91 K.

N.Z.I. Hashim

Papers

Review of Fe-based spin crossover metal complexes in multiscale device architectures