Probing Magnetic Excitations in CoII Single‐Molecule Magnets by Inelastic Neutron Scattering. Issue 8 (17th December 2018)

• Record Type: Journal Article
• Authors: Stavretis, Shelby E.; Cheng, Yongqiang; Daemen, Luke L.; Brown, Craig M.; Moseley, Duncan H.; Bill, Eckhard; Atanasov, Mihail; Ramirez‐Cuesta, Anibal J.; Neese, Frank; Xue, Zi‐Ling
• Other Names: Stride John A. guestEditor.; Queen Wendy L. guestEditor.; Romerosa Antonio guestEditor.
• Is Part Of: European journal of inorganic chemistry. Issue 8(2019)
• Page Start: 1119
• Page End: 1127
• Publication Date: 2018-12-17
• Subjects: Cobalt -- Zero‐field splitting -- Inelastic neutron scattering -- Phonons -- DFT phonon calculations; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201801088
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : Co(acac)2 (H2 O)2 (1, acac = acetylacetonate), a transition metal complex ( S = 3/2), displays field‐induced slow magnetic relaxation as a single‐molecule magnet. For1 and its isotopologues Co(acac)2 (D2 O)2 (1‐ d 4 ) and Co(acac‐ d 7 )2 (D2 O)2 (1‐ d 18 ) in approximately D 4 h symmetry, zero‐field splitting of the ground electronic state leads to two Kramers doublets (KDs): lower energy MS = ±1/2 ( ϕ 1, 2 ) and higher energy MS = ±3/2 ( ϕ 3, 4 ) states. This work employs inelastic neutron scattering (INS), a unique method to probe magnetic transitions, to probe different magnetic excitations in1‐ d 4 and1‐ d 18 . Direct‐geometry, time‐of‐flight Disk‐Chopper Spectrometer (DCS), with applied magnetic fields up to 10 T, has been used to study the intra‐KD transition as a result of Zeeman splitting, MS = –1/2 ( ϕ 1 ) → MS = +1/2 ( ϕ 2 ), in1‐ d 18 . This is a rare study of the MS = –1/2 → MS = +1/2 excitation in transition metal complexes by INS. Indirect‐geometry INS spectrometer VISION has been used to probe the inter‐KD, ZFS transition, MS = ±1/2 ( ϕ 1, 2 ) → MS = ±3/2 ( ϕ 3, 4 ) in both1‐ d 4 and1‐ d 18, by variable‐temperature (VT) properties of this excitation. The INS spectra measured on VISION also give phonon features of the complexes that are well described by periodic DFT phonon calculations. Abstract : Inelastic Neutron Scattering (INS) has been used to probe intra‐ and inter‐Kramers doublet transitions in Co(acac‐ d 7 )2 (D2 O)2 (1‐ d 18 ) using both variable‐magnetic fields and temperatures. These measurements and INS of Co(acac)2 (D2 O)2 (1‐ d 4 ), coupled with periodic DFT phonon calculations, help reveal magnetic and vibrational properties of the single‐molecule magnets (SMMs).