title: A two-in-one pincer ligand and its diiron(II) complex showing spin state switching in solution through reversible ligand exchange.
abstract: A novel pyrazolate-bridged ligand providing two {PNN} pincer-type compartments has been synthesized. Its diiron(II) complex LFe2(OTf)3(CH3CN) (1; Tf = triflate) features, in solid state, two bridging triflate ligands, with a terminal triflate and a MeCN ligand completing the octahedral coordination spheres of the two high-spin metal ions. In MeCN solution, 1 is shown to undergo a sequential, reversible, and complete spin transition to the low-spin state upon cooling. Detailed UV/Vis and (19)F NMR spectroscopic studies as well as magnetic measurements have unraveled that spin state switching correlates with a rapid multistep triflate/MeCN ligand exchange equilibrium. The spin transition temperature can be continuously tuned by varying the triflate concentration in solution.
authors.affiliation: Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen (Germany) http://www.meyer.chemie.uni-goettingen.de.
authors.forename: Subhas
authors.initials: S
authors.lastname: Samanta
authors.forename: Serhiy
authors.initials: S
authors.lastname: Demesko
authors.forename: Sebastian
authors.initials: S
authors.lastname: Dechert
authors.forename: Franc
authors.initials: F
authors.lastname: Meyer
keywords: diiron complexes; ligand exchange; magnetic properties; pincer ligands; spin crossover