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- Title
Crystal growth and physical properties of an antiferromagnetic molecule: trans‐dibromidotetrakis(acetonitrile)chromium(III) tribromide, [CrBr<sub>2</sub>(NCCH<sub>3</sub>)<sub>4</sub>](Br<sub>3</sub>).
- Authors
Dissanayaka Mudiyanselage, Ranuri S.; Kong, Tai; Xie, Weiwei
- Abstract
The synthesis, crystal structure determination, magnetic properties and bonding interaction analysis of a novel 3d transition‐metal complex, [CrBr2(NCCH3)4](Br3), are reported. Single‐crystal X‐ray diffraction results show that [CrBr2(NCCH3)4](Br3) crystallizes in space group C2/m (No. 12) with a symmetric tribromide anion and the powder X‐ray diffraction results show the high purity of the material specimen. X‐ray photoelectron studies with a combination of magnetic measurements demonstrate that Cr adopts the 3+ oxidation state. Based on the Curie–Weiss analysis of magnetic susceptibility data, the Néel temperature is found to be around 2.2 K and the effective moment (μeff) of Cr3+ in [CrBr2(NCCH3)4](Br3) is ∼3.8 µB, which agrees with the theoretical value for Cr3+. The direct current magnetic susceptibility of the molecule shows a broad maximum at ∼2.3 K, which is consistent with the theoretical Néel temperature. The maximum temperature, however, shows no clear frequency dependence. Combined with the observed upturn in heat capacity below 2.3 K and the corresponding field dependence, it is speculated that the low‐temperature magnetic feature of a broad transition in [CrBr2(NCCH3)4](Br3) could originate from a crossover from high spin to low spin for the split d orbital level low‐lying states rather than a short‐range ordering solely; this is also supported by the molecular orbital diagram obtained from theoretical calculations.
- Subjects
CRYSTAL growth; SINGLE molecule magnets; MAGNETIC measurements; X-ray powder diffraction; ACETONITRILE; TRANSITION metal alloys; ANTIFERROMAGNETIC materials
- Publication
Acta Crystallographica Section B: Structural Science, Crystal Engineering & Materials, 2021, Vol 77, Issue 4, p624
- ISSN
2052-5192
- Publication type
Article
- DOI
10.1107/S2052520621004662