Structural Studies into the Spin Crossover Behaviour of Fe(abpt)2(NCS)2 Polymorphs B and D

Helen E. Mason; Jake R. C. Musselle-Sexton; Judith A. K. Howard; Michael R. Probert; Hazel A. Sparkes

doi:10.1039/d1nj02607k

Structural Studies into the Spin Crossover Behaviour of Fe(abpt)₂(NCS)₂ Polymorphs B and D

Helen E. Mason, Jake R. C. Musselle-Sexton, Judith A. K. Howard, Michael R. Probert, Hazel A. Sparkes^*

^*Corresponding author for this work

School of Chemistry

Research output: Contribution to journal › Article (Academic Journal) › peer-review

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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 measurements on polymorph B showed that it underwent a monoclinic P2₁/n (Z’ = 0.5) to triclinic P-1 (Z’ = 2 x 0.5) phase transition between 11.5-13.5 kbar. At which point, it also starts to undergo a thermally inaccessible spin crossover. In polymorph D which also crystallises in the mononclinic space group P2₁/n (Z’ = 2 x 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 transitions.

Original language	English
Pages (from-to)	14014-14023
Number of pages	10
Journal	New Journal of Chemistry
Volume	45
Issue number	31
Early online date	12 Jul 2021
DOIs	https://doi.org/10.1039/d1nj02607k
Publication status	Published - 21 Aug 2021

Bibliographical note

Funding Information:
H. E. M. was grateful to Professor Jonathan W. Steed (Durham University) for useful discussions. She was also grateful to the EPSRC and Durham University for financial support.

Publisher Copyright:
© The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021.

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@article{e77567a1f3284bb98aad9d121bc58f89,

title = "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 measurements on polymorph B showed that it underwent a monoclinic P21/n (Z{\textquoteright} = 0.5) to triclinic P-1 (Z{\textquoteright} = 2 x 0.5) phase transition between 11.5-13.5 kbar. At which point, it also starts to undergo a thermally inaccessible spin crossover. In polymorph D which also crystallises in the mononclinic space group P21/n (Z{\textquoteright} = 2 x 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 transitions. ",

author = "Mason, {Helen E.} and Musselle-Sexton, {Jake R. C.} and Howard, {Judith A. K.} and Probert, {Michael R.} and Sparkes, {Hazel A.}",

note = "Funding Information: H. E. M. was grateful to Professor Jonathan W. Steed (Durham University) for useful discussions. She was also grateful to the EPSRC and Durham University for financial support. Publisher Copyright: {\textcopyright} The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021.",

year = "2021",

month = aug,

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doi = "10.1039/d1nj02607k",

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T1 - Structural Studies into the Spin Crossover Behaviour of Fe(abpt)2(NCS)2 Polymorphs B and D

AU - Mason, Helen E.

AU - Musselle-Sexton, Jake R. C.

AU - Howard, Judith A. K.

AU - Probert, Michael R.

AU - Sparkes, Hazel A.

N1 - Funding Information: H. E. M. was grateful to Professor Jonathan W. Steed (Durham University) for useful discussions. She was also grateful to the EPSRC and Durham University for financial support. Publisher Copyright: © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021.

PY - 2021/8/21

Y1 - 2021/8/21

N2 - 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 measurements on polymorph B showed that it underwent a monoclinic P21/n (Z’ = 0.5) to triclinic P-1 (Z’ = 2 x 0.5) phase transition between 11.5-13.5 kbar. At which point, it also starts to undergo a thermally inaccessible spin crossover. In polymorph D which also crystallises in the mononclinic space group P21/n (Z’ = 2 x 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 transitions.

AB - 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 measurements on polymorph B showed that it underwent a monoclinic P21/n (Z’ = 0.5) to triclinic P-1 (Z’ = 2 x 0.5) phase transition between 11.5-13.5 kbar. At which point, it also starts to undergo a thermally inaccessible spin crossover. In polymorph D which also crystallises in the mononclinic space group P21/n (Z’ = 2 x 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 transitions.

U2 - 10.1039/d1nj02607k

DO - 10.1039/d1nj02607k

M3 - Article (Academic Journal)

SN - 1144-0546

VL - 45

SP - 14014

EP - 14023

JO - New Journal of Chemistry

JF - New Journal of Chemistry

IS - 31

ER -