Thermochromic Meltable Materials with Reverse Spin Transition Controlled by Chemical Design

Abstract

We report aseries of meltable Fe II complexes,which, depending on the length of aliphatic chains,d isplaya brupt forwardl ow-spin to high-spin transition or unprecedented melting-triggered reverse high-spin to low-spin transition on temperature rise.T he reverse spin transition is perfectly reproducible on thermal cycling and the obtained materials are easily processable in the form of thin film owing to their soft-matter nature.W ef ound that the discovered approach represents ap otentially generalizable new avenue to control both the location in temperature and the direction of the spin transition in meltable compounds. Scheme 1. Synthetic pathway for the pyN-n and pm2-n.

Crystal structure of {N 1,N 3-bis[(1-benzyl-1H-1,2,3-triazol-4-yl)methylidene]-2,2-dimethylpropane-1,3-diamine}bis(thiocyanato-κN)iron(II)

“…Having ongoing interest in functional 3d metal complexes formed by polydentate ligands (Seredyuk et al, 2006(Seredyuk et al, , 2007(Seredyuk et al, , 2011(Seredyuk et al, , 2015(Seredyuk et al, , 2016Seredyuk, 2012;Valverde-Muñ oz et al, 2020), we report here the synthesis and crystal structure of a new high-spin Fe II complex based on the tetradentate ligand N 1 ,N 3 -bis[(1-benzyl-1H-1,2,3-triazol-4-yl)methylene]-2,2-dimethylpropane-1,3-diamine with thiocyanate anions arranged in a cis-configuration.…”

Thermodriven, Acidity-Driven, and Photodriven Spin-State Switching in Pyridylacylhydrazoneiron(II) Complexes at or above Room Temperature

“…Although solely light-driven bidirectional switching has not been achieved yet, separation of the absorptions in E and Z isomers is a bright direction worth exploring. The easy, scalable, and modular syntheses of acylhydrazone ligands − hold promising prospects toward this end. Future studies are ongoing in our laboratory.…”

Crystal structure of (N 1,N 3-bis{[1-(4-methoxybenzyl)-1H-1,2,3-triazol-4-yl]methylidene}-2,2-dimethylpropane-1,3-diamine)bis(thiocyanato)iron(II)

“…Having ongoing interest in functional 3d-metal complexes formed by polydentate ligands (Seredyuk et al, 2006, ISSN 2056-9890 2011Seredyuk, 2012;Valverde-Muñ oz et al, 2020), we report here the synthesis and crystal structure of a new Fe II complex based on the tetradentate ligand N 1 ,N 3 -bis{[1-(4-methoxybenzyl)-1H-1,2,3-triazol-4-yl]methylene}-2,2-dimethylpropane-1,3-diamine with thiocyanate anions arranged around the iron(II) atom in a cis-configuration.…”