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

Lookup NU author(s): Dr Jake Musselle-Sexton, Professor Judith Howard, Professor Mike ProbertORCiD



This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).


© The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021. 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 has been studied using single crystal X-ray diffraction to monitor changes in structural features. High pressure single crystal measurements on polymorph B showed that it underwent a monoclinicP21/n(Z′ = 0.5) to triclinicP-1 (Z′ = 2 × 0.5) phase transition between 11.5 and 13.5 kbar, at which point it also starts to undergo a thermally inaccessible spin crossover. In polymorph D which also crystallises in the mononclinic space groupP21/n(Z′ = 2 × 0.5) one of the unique Fe centres undergoes a thermal spin transition. It also displays light-induced excited spin-state trapping (LIESST), and a structure has been obtained at 30 K through continuous irradiation with a 670 nm 5 mW CW laser. In addition high pressure single crystal measurements on polymorph D showed a stepped pressure induced spin transition. At ∼9.6 kbar one of the unique Fe centres had undergone a spin transition and by ∼15 kbar both of the unique Fe centres are shown to be essentially low spin, a situation that is thermally inaccessible. Crystallographic data were collected for both polymorphs using variable temperature or high pressure single crystal X-ray diffraction to allow changes in cell parameters, bond lengths and distortion parameters to be monitored for the spin crossover or phase transition.

Publication metadata

Author(s): Mason HE, Musselle-Sexton JRC, Howard JAK, Probert MR, Sparkes HA

Publication type: Article

Publication status: Published

Journal: New Journal of Chemistry

Year: 2021

Volume: 45

Issue: 31

Pages: 14014-14023

Print publication date: 21/08/2021

Online publication date: 12/07/2021

Acceptance date: 12/07/2021

Date deposited: 26/08/2021

ISSN (print): 1144-0546

ISSN (electronic): 1369-9261

Publisher: Royal Society of Chemistry


DOI: 10.1039/d1nj02607k


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