Structural studies into the spin crossover behaviour of Fe(abpt)₂(NCS)₂ polymorphs B and D

Abstract

The spin-crossover behaviour of [Fe(abpt)2(NCS)2] (abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) polymorphs B and D have been studied using single crystal X-ray diffraction to monitor changes in structural features. High pressure single crystal...

Co(NCS)2(abpt)2 and Ni(NCS)2(abpt)2 [abpt is 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole]: structural characterization of polymorphs A and B

“…As seen for the pair of polymorph A structures, the two polymorph B structures were also isostructural with each other and with the previously reported Fe(NCS) 2 (abpt) 2 polymorph B structure (Gaspar et al, 2003;Mason et al, 2021). The structures of polymorph B also displayinteractions, but in this case each of the pyridyl rings on the abpt ligand is involved in ainteraction to a pyridyl ring on a different abpt ligand, creating a threedimensional network of interactions in the structure (Table 3 and Fig.…”

“…Three of the polymorphs, i.e. A (Moliner et al, 1999;Sheu et al, 2009;Mason et al, 2016), C (Sheu et al, 2009;Shih et al, 2010) and D (Sheu et al, 2009(Sheu et al, , 2012Mason et al, 2021), undergo at least a partial thermal spin crossover under ambient pressure, while polymorph B (Gaspar et al, 2003) only undergoes a thermal spin crossover at pressures above 4.4 kbar (1 bar = 10 5 Pa). All of the three polymorphs which display at least a partial thermal spin crossover also show light-induced excited-spinstate trapping (LIESST) at low temperature.…”

“…All of the three polymorphs which display at least a partial thermal spin crossover also show light-induced excited-spinstate trapping (LIESST) at low temperature. While three of the polymorphs (A, B and D) are known to undergo a pressure-induced spin crossover at room temperature (Mason et al, 2016(Mason et al, , 2021, polymorph C has not been studied under pressure at room temperature. To date, Co(NCS) 2 (abpt) 2 is the only other M(NCS) 2 (abpt) 2 complex containing a transition metal for which any structures have been reported.…”

Fine-tuning of thermally induced SCO behaviors of trinuclear cyanido-bridged complexes by regulating the electron donating ability of CCN-terminal fragments

“…Besides, all of the mononuclear Fe (abpt) 2 X 2 complexes without intermolecular π-π interactions did not undergo a thermal spin crossover. 42 Obviously, compared with reported mononuclear Fe (abpt) 2 X 2 , the influence of intermolecular π-π interactions on the SCO behavior is very weak for the trinuclear complexes 1-4. All 1-4 exhibit thermally induced SCO behaviors (see below), although there is no intermolecular π-π interaction in complexes 1 and 2.…”

“…Besides, all of the mononuclear Fe(abpt) 2 X 2 complexes without intermolecular π–π interactions did not undergo a thermal spin crossover. 42…”