Electronic Structure and Magnetic Anisotropy of an Unsaturated Cyclopentadienyl Iron(I) Complex with 15 Valence Electrons. Issue 27 (30th May 2017)

• Record Type: Journal Article
• Authors: Chakraborty, Uttam; Demeshko, Serhiy; Meyer, Franc; Rebreyend, Christophe; de Bruin, Bas; Atanasov, Mihail; Neese, Frank; Mühldorf, Bernd; Wolf, Robert
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 27(2017)
• Page Start: 7995
• Page End: 7999
• Publication Date: 2017-05-30
• Subjects: carbene ligands -- cyclopentadienyl ligands -- homogeneous catalysis -- iron -- magnetic properties; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201702454
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The 15 valence‐electron iron(I) complex [Cp Ar Fe(IiPr2 Me2 )] (1, Cp Ar =C5 (C6 H4 ‐4‐Et)5 ; IiPr2 Me2 =1, 3‐diisopropyl‐4, 5‐dimethylimidazolin‐2‐ylidene) was synthesized in high yield from the Fe II precursor [Cp Ar Fe(μ‐Br)]2 . 57 Fe Mössbauer and EPR spectroscopic data, magnetic measurements, and ab initio ligand‐field calculations indicate an S= 3/2 ground state with a large negative zero‐field splitting. As a consequence, 1 features magnetic anisotropy with an effective spin‐reversal barrier of Ueff =64 cm −1 . Moreover, 1 catalyzes the dehydrogenation of N, N‐dimethylamine–borane, affording tetramethyl‐1, 3‐diaza‐2, 4‐diboretane under mild conditions. Abstract : Iron(I) in action : The 15 valence‐electron complex [Cp Ar Fe(I i Pr2 Me2 )] is stabilized by the pentaaryl‐substituted cyclopentadienyl ligand C5 (C6 H4 ‐4‐Et)5 (Cp Ar ) and the N‐heterocyclic carbene 1, 3‐diisopropyl‐4, 5‐dimethylimidazolin‐2‐ylidene (I i Pr2 Me2 ). This compound is a new type of iron‐based single‐molecule magnet owing to an unusual configuration of the 3d orbitals in the ground state.