Publication detail

Lattice solvent- and substituent-dependent spin-crossover in isomeric iron(ii) complexes

Kuppusamy, SK. Mizuno, A. Kämmerer, L. Salamon, S. Heinrich, B. Bailly, C. Salitros, I. Wende, H. Ruben, M.

Original Title

Lattice solvent- and substituent-dependent spin-crossover in isomeric iron(ii) complexes

Type

journal article in Web of Science

Language

English

Original Abstract

Spin-state switching in iron(ii) complexes composed of ligands featuring moderate ligand-field strength-for example, 2,6-bi(1H-pyrazol-1-yl)pyridine (BPP)-is dependent on many factors. Herein, we show that spin-state switching in isomeric iron(ii) complexes composed of BPP-based ligands-ethyl 2,6-bis(1H-pyrazol-1-yl)isonicotinate (BPP-COOEt, L1) and (2,6-di(1H-pyrazol-1-yl)pyridin-4-yl)methylacetate (BPP-CH2OCOMe, L2)-is dependent on the nature of the substituent at the BPP skeleton. Bi-stable spin-state switching-with a thermal hysteresis width (Delta T-1/2) of 44 K and switching temperature (T-1/2) = 298 K in the first cycle-is observed for complex 1CH3CN composed of L1 and BF4- counter anions. Conversely, the solvent-free isomeric counterpart of 1CH3CN-complex 2a, composed of L2 and BF4- counter anions-was trapped in the high-spin (HS) state. For one of the polymorphs of complex 2bCH3CN-2bCH3CN-Y, Y denotes yellow colour of the crystals-composed of L2 and ClO4- counter anions, a gradual and non-hysteretic SCO is observed with T-1/2 = 234 K. Complexes 1CH3CN and 2bCH3CN-Y also underwent light-induced spin-state switching at 5 K due to the light-induced excited spin-state trapping (LIESST) effect. Structures of the low-spin (LS) and HS forms of complex 1CH3CN revealed that spin-state switching goes hand-in-hand with pronounced distortion of the trans-N{pyridyl}-Fe-N{pyridyl} angle (phi), whereas such distortion is not observed for 2bCH3CN-Y. This observation points that distortion is one of the factors making the spin-state switching of 1CH3CN hysteretic in the solid state. The observation of bi-stable spin-state switching with T-1/2 centred at room temperature for 1CH3CN indicates that technologically relevant spin-state switching profiles based on mononuclear iron(ii) complexes can be obtained.

Keywords

ROOM-TEMPERATURE FERROELECTRICITY; MAGNETIC BISTABILITY; TRANSITION

Authors

Kuppusamy, SK.; Mizuno, A.; Kämmerer, L.; Salamon, S.; Heinrich, B.; Bailly, C.; Salitros, I.; Wende, H.; Ruben, M.

Released

2. 7. 2024

Publisher

ROYAL SOC CHEMISTRY

Location

CAMBRIDGE

ISBN

1477-9234

Periodical

Dalton Transactions

Year of study

53

Number

26

State

United Kingdom of Great Britain and Northern Ireland

Pages count

16

URL

https://pubs.rsc.org/en/content/articlelanding/2024/dt/d4dt00429a

BibTex

@article{BUT189998,
  author="Kuppusamy, SK. and Mizuno, A. and Kämmerer, L. and Salamon, S. and Heinrich, B. and Bailly, C. and Salitros, I. and Wende, H. and Ruben, M.",
  title="Lattice solvent- and substituent-dependent spin-crossover in isomeric iron(ii) complexes",
  journal="Dalton Transactions",
  year="2024",
  volume="53",
  number="26",
  pages="16",
  doi="10.1039/d4dt00429a",
  issn="1477-9234",
  url="https://pubs.rsc.org/en/content/articlelanding/2024/dt/d4dt00429a"
}