Coordination‐Induced Spin‐State Switching of an Aminyl‐Radical‐Bridged Nickel(II) Porphyrin Dimer between Doublet and Sextet States. Issue 15 (12th March 2019)

• Record Type: Journal Article
• Authors: Shimizu, Daiki; Ide, Yuki; Ikeue, Takahisa; Osuka, Atsuhiro
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 15(2019)
• Page Start: 5023
• Page End: 5027
• Publication Date: 2019-03-12
• Subjects: coordination-induced spin-state switch -- molecular magnetism -- nickel -- porphyrins -- radicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201900792
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A bis(Ni II ‐porphyrinyl)aminyl radical with meso ‐C6 F5 groups was prepared as a spin‐delocalized stable aminyl radical with a doublet spin state. Upon addition of pyridine, both Ni II centers became hexacoordinated by accepting two axial pyridines, which triggered a spin‐state change of the Ni II centers from diamagnetic ( S= 0) to paramagnetic ( S= 1). The resulting high‐spin Ni II centers interact with the aminyl radical ferromagnetically to give rise to an overall sextet state ( S= 5/2). Importantly, this coordination‐induced spin‐state switching can be conducted in a reversible manner, in that washing of the high‐spin radical with aqueous hydrochloric acid regenerates the original doublet radical in good yield. Abstract : Flick the switch : An aminyl radical bridged Ni II ‐porphyrin dimer is a doublet ( S= 1/2) but can be reversibly switched to a sextet ( S= 5/2) upon addition of pyridine ligands by coordination‐induced spin‐state switch (CISSS) owing to ferromagnetic interaction between the high‐spin Ni II centers and aminyl radical.