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Slow magnetic relaxation in octahedral low-spin Ni(iii) complexes.

ABSTRACT: Herein we report the first examples of single-molecule magnet (SMM) behaviour in S = 1/2 Ni(iii) complexes. We find that low-spin 3d⁷ trans-[Ni^III(cyclam)(X)₂]Y complexes (cyclam = 1,4,8,11-tetraazacyclotetradecane; X and Y are singly charged anions) exhibit field-induced slow relaxation of magnetization for O-donor axial ligands (nitrate) but not for N-donor variants (isothiocyanate). Experimental and electronic structure computational investigations indicate that intrinsic spin polarisation of low-spin Ni(iii) is modulated significantly by local coordination geometry and supramolecular interactions. Solid state dilution of Ni(iii) with diamagnetic Co(iii) ions forms a related complex salt, [Ni _x Co_1-x (cyclam)(NO₃)₂](NO₃)·2HNO₃ (0.1 < x < 1), which preserves slow magnetic dynamics, thus supporting a molecular component to slow relaxation. An initial analysis of magnetic relaxation lifetime fits best to a combination of Raman and direct relaxation processes.

SUBMITTER: Bhowmick I

PROVIDER: S-EPMC6115677 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Slow magnetic relaxation in octahedral low-spin Ni(iii) complexes.

Bhowmick Indrani I Roehl Andrew J AJ Neilson James R JR Rappé Anthony K AK Shores Matthew P MP

Chemical science 20180712 31

Herein we report the first examples of single-molecule magnet (SMM) behaviour in S = 1/2 Ni(iii) complexes. We find that low-spin 3d7 trans-[NiIII(cyclam)(X)2]Y complexes (cyclam = 1,4,8,11-tetraazacyclotetradecane; X and Y are singly charged anions) exhibit field-induced slow relaxation of magnetization for O-donor axial ligands (nitrate) but not for N-donor variants (isothiocyanate). Experimental and electronic structure computational investigatio ...[more]

PMID: 30310588

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