Chiral spin crossover nanoparticles and gels with switchable circular dichroism

July 28, 2017

Title

Chiral spin crossover nanoparticles and gels with switchable circular dichroism

Author

Il'ya A. Gural'skiy, Viktor A. Reshetnikov, Agnieszka Szebesczyk, Elzbieta Gumienna-Kontecka, Andriy I. Marynin, Sergii I. Shylin, Vadim Ksenofontov, Igor O. Fritsky

Year

2015

Journal

Journal of Materials Chemistry C

Abstract

Spin crossover complexes represent spectacular examples of molecular switchable materials. We describe a new approach towards homochiral coordination nanoparticles of [Fe(NH2trz)3](L-CSA)2 (NH2trz = 4-amino-1,2,4-triazole, L-CSA = L-camphorsulfonate) that display an abrupt switch of chiral properties associated with a cooperative spin transition. This is an original method that generates stable and additive-free colloidal solutions of nanoparticles with a spin transition around room temperature. The introduction of a chiral anion to the coordination framework makes these nanoparticles display specific chiro-optical (circular dichroism) properties that are different in high and low spin states. We also illustrate here an effect of the “chiral memory” which is caused by the hysteretic spin transition. In addition, a bistable chiral composite supramolecular system – a [Fe(NH2trz)3](L-CSA)2–CHCl3 gel – is described here.

Instrument

J-715

Keywords

Circular dichroism, Coordination chemistry, Thermal stability, Materials