Meltable Spin Transition Molecular Materials with Tunable T_c and Hysteresis Loop Width

Abstract

Herein, we report a way to achieve abrupt high-spin to low-spin transition with controllable transition temperature and hysteresis width, relying not on solid-state cooperative interactions, but utilizing coherency between phase and spin transitions in neutral Fe(II) meltable complexes.

Complete Set of Elastic Moduli of a Spin-Crossover Solid: Spin-State Dependence and Mechanical Actuation

“…Cantilever bending [19] Single crystal crystalline SCO complexes [41] and also to alter the SCO properties of iron-triazole complexes. [42] This approach appears thus as a viable strategy to modulate (i.e.…”

Iron(II) Spin Crossover Complexes with 4,4′-Dipyridylethyne—Crystal Structures and Spin Crossover with Hysteresis

“…Nevertheless, there is still a lot to be learned for the different substance families to further improve this understanding. The detailed understanding of the interplay of packing parameters and observed thermal hysteresis loop is very important for potential applications, especially if the complexes are to be incorporated into composite materials, for examples as nanoparticles [39][40][41][42][43][44][45], or if additional properties are to be incorporated without losing the cooperative spin crossover properties [46][47][48][49][50].…”

Crystal structure of the mixed methanol and ethanol solvate of bis{3,4,5-trimethoxy-N′-[1-(pyridin-2-yl)ethylidene]benzohydrazidato}zinc(II)

“…Neighbouring dimers are bound along [010] by weak hydrogen bonds between the pyridine rings and methoxy groups, C18Á Á ÁO3 ii [symmetry code: (ii) Àx, Ày, Àz + 1] = 3.100 (5) Å (Table 1), with the closest ZnÁ Á ÁZn ii interdimer separation of 6.965 (5) Å . It is worth noting that a related Fe II pyridinebased complex with butyl substituents consisting of uniform supramolecular chains with FeÁ Á ÁFe separation of 7.676 Å has previously been described (Romero-Morcillo et al, 2015). The supramolecular chains of the title compound are packed in the lattice with the closest interchain separations coinciding with the unit-cell parameters a = 11.0402 (4) Å and b = 13.8056 (8) Å .…”

“…The aroylhydrazone ligands can form charged complexes or can easily be deprotonated due to tautomerism, thus forming neutral species. These dynamic reversible properties have led to the exploration of charged and neutral spin-crossover iron(II) and iron(III) complexes, some with multifunctional properties (Zhang et al, 2010;Shongwe et al, 2012;Romero-Morcillo et al, 2015;Yuan et al, 2019). As part of our continuing interest in studying 3d metal complexes formed by polydentate ligands bearing alkoxy substituents (Seredyuk, 2012;Seredyuk et al, 2006Seredyuk et al, , 2011Seredyuk et al, , 2016 and those based on polydentate ligands (Seredyuk et al, 2007(Seredyuk et al, , 2015, we report here the synthesis and crystal structure of a neutral Zn II complex formed with the tridentate ligand 3,4,5-trimethoxy-N 0 -[1-(pyridin-2-yl)ethylidene]benzohydrazide.…”