Single-molecule magnetism within a family of [LnIII2MnIII10] complexes from 2-hydroxymethylpyridine. (1st March 2018)

• Record Type: Journal Article
• Authors: Bagai, Rashmi; Wernsdorfer, Wolfgang; Abboud, Khalil A.; Christou, George
• Is Part Of: Polyhedron. Volume 142(2018)
• Page Start: 49
• Page End: 57
• Publication Date: 2018-03-01
• Subjects: Manganese -- Lanthanides -- Clusters -- Crystal structure -- Single-molecule magnetism; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2017.12.005
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: Heterometallic [Ln III 2 Mn III 10 ] (Ln = lanthanide) clusters, and their [Y III 2 Mn III 10 ] analog, have been synthesized. The Tb, Dy and Ho complexes are single-molecule magnets, confirmed for the Dy complex by the observation of hysteresis loops. Abstract: A family of heterometallic Ln/Mn (Ln = lanthanide) clusters with a [Ln III 2 Mn III 10 ] core has been synthesized. The complexes [Ln2 Mn10 O8 (O2 CPh)10 (hmp)6 (NO3 )4 ] (Ln = Pr (1 ), Nd (2 ), Sm (3 ), Gd (4 ), Tb (5 ), Dy (6 ), Ho (7 ) and Er (8 )) were prepared from the reaction of (NBu4 )[Mn4 O2 (O2 CPh)9 (H2 O)], 2-hydroxymethylpyridine (hmpH) and Ln(NO3 )3 . The analog with diamagnetic Y III, [Y2 Mn10 O8 (O2 CPh)10 (hmp)6 (NO3 )4 ] (9 ), was also synthesized to assist the magnetic studies. Representative complexes4, 6 and9 were characterized by X-ray crystallography, and they contain a layered [Mn10 O8 ] 14+ core attached at each end to a Ln III or Y III atom. Complexes5, 6 and7 exhibit frequency-dependent out-of-phase ( χM ″) ac susceptibility signals indicating the slow magnetization relaxation of single-molecule magnets (SMMs). Magnetization versus applied dc field hysteresis loops on single crystals of representative complex6 ·3MeCN·MeOH have established it to be a new addition to the family of Mn-Ln SMMs. Relaxation rate versus temperature data for6 obtained from variable-frequency χM ″ versus T studies down to 1.8 K were combined with those from dc magnetization decay versus time measurements at lower temperatures, and these were fit to the Arrhenius equation to give an effective barrier to magnetization relaxation ( U eff ) of 30 K.