title: Light-induced spin-state switching in the mixed crystal series of the 2D coordination network {[Zn1-xFex(bbtr)3](BF4)2}∞: optical spectroscopy and cooperative effects.
abstract: Depending on the iron(ii) concentration, the mixed crystals of {[Zn1-xFex(bbtr)3](BF4)2}∞, bbtr = 1,4-di(1,2,3-triazol-1-yl)butane, 0.01 ≤ x ≤ 1, show macroscopic light-induced bistability between the high-spin and the low-spin state. In the highly diluted system with x = 0.01 and up to x = 0.31, the photoinduced low-spin state always relaxes back to the high-spin state independent of the initial light-induced low-spin fraction. In the highly concentrated mixed crystals with x = 0.67, 0.87 and 1, the strong cooperative effects coupled to a crystallographic phase transition result in light-induced bistability with decreasing critical light-induced low-spin fraction and increasing hysteresis width for increasing iron(ii) concentrations. The lower limit for the light-induced bistability was estimated to be x ≈ 0.5.
authors.affiliation: Département de Chimie Physique, Université de Genève, 30 Quai Ernest-Ansermet, 1211 Genève, Switzerland. andreas.hauser@unige.ch.
authors.forename: Pradip
authors.initials: P
authors.lastname: Chakraborty
authors.forename: Cristian
authors.initials: C
authors.lastname: Enachescu
authors.forename: Arnaud
authors.initials: A
authors.lastname: Humair
authors.forename: Leo
authors.initials: L
authors.lastname: Egger
authors.forename: Teresa
authors.initials: T
authors.lastname: Delgado
authors.forename: Antoine
authors.initials: A
authors.lastname: Tissot
authors.forename: Laure
authors.initials: L
authors.lastname: Guénée
authors.forename: Céline
authors.initials: C
authors.lastname: Besnard
authors.forename: Robert
authors.initials: R
authors.lastname: Bronisz
authors.forename: Andreas
authors.initials: A
authors.lastname: Hauser