Abrupt spin crossover in iron(iii) complexes with aromatic anions

Sharon E Lazaro; Adil Alkaş; Seok J Lee; Shane G Telfer; Keith S Murray; Wasinee Phonsri; Phimphaka Harding; David J Harding

doi:10.1039/c9dt02373a

Abrupt spin crossover in iron(iii) complexes with aromatic anions

Dalton Trans. 2019 Nov 7;48(41):15515-15520. doi: 10.1039/c9dt02373a. Epub 2019 Jul 15.

Authors

Sharon E Lazaro¹, Adil Alkaş², Seok J Lee², Shane G Telfer², Keith S Murray³, Wasinee Phonsri³, Phimphaka Harding¹, David J Harding¹

Affiliations

¹ Functional Materials and Nanotechnology Center of Excellence, Walailak University, Thasala, Nakhon Si Thammarat 80160, Thailand. kphimpha@mail.wu.ac.th hdavid@mail.wu.ac.th.
² MacDiarmid Institute for Advanced Materials and Nanotechnology, Institute of Fundamental Sciences, Massey University, New Zealand.
³ School of Chemistry, Monash University, Clayton, Melbourne, Victoria 3800, Australia.

PMID: 31304498
DOI: 10.1039/c9dt02373a

Abstract

Two iron(iii) spin crossover complexes, [Fe(qsal-X)₂]OTs·nH₂O, (Br 1·H₂O; I, 2·2H₂O or non-solvated 1, 2) have been prepared and fully characterized. Structural studies of 1·H₂O and 2·2H₂O reveal the presence of 1D π-π chains linking the Fe(iii) centres and a strong XO halogen bond. In both complexes the 1D π-π chains are angled relative to each other, enforced by C-HX interactions. Magnetic studies reveal abrupt spin crossover in 1 (T_1/2↓ = 258 K and T_1/2↑ = 260 K) and 2 (T_1/2 = 298 K) with T_1/2 increasing on going from Br to I. The presence of abrupt spin crossover in both complexes shows that aromatic anions can be effective in the design of cooperative spin crossover systems.