Influence of Mn/Ca ratio in Mn-Ca coordination clusters: Synthesis, structure, and magnetic characterisation. (15th September 2021)

• Record Type: Journal Article
• Authors: Ako, Ayuk M.; Anson, Christopher E.; Clérac, Rodolphe; Fitzpatrick, Anthony J.; Müller-Bunz, Helge; Carter, Anthony B.; Morgan, Grace G.; Powell, Annie K.
• Is Part Of: Polyhedron. Volume 206(2021)
• Publication Date: 2021-09-15
• Subjects: Manganese -- Calcium -- Coordination cluster -- Molecular magnetism; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2021.115325
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: Reactions of MnCl2 ·4H2 O and CaCl2 with 2, 6-bis(hydroxymethyl)-4-methylphenol and NaN3 gave Mn III 3 Ca3 or Mn III 12 Mn II Ca II 6 coordination clusters, depending on the Mn:Ca ratio used; the magnetic properties of both clusters were modelled. Abstract: Similar reactions of MnCl2 ·4H2 O and CaCl2 with 2, 6-bis(hydroxymethyl)-4-methylphenol gave heterometallic coordination clusters with very different nuclearities, depending on the Mn:Ca ratio used. With a 1:1 ratio, the hexanuclear cluster [Mn III 3 Ca II 3 (μ3 -Cl(HL Me )6 (H2 O)6 ]Cl2 ·6.74H2 O (2) with a "triangle-in-triangle" topology was obtained. However, a Mn:Ca ratio of 2:1 resulted in [Mn III 12 Mn II Ca II 6 (μ4 -O)8 (μ3 -Cl)3.7 (μ3 -η 1 -N3 )4.3 (HL Me )12 (MeCN)6 ]Cl2 ∙15MeOH (3), which corresponds structurally to the replacement by Ca 2+ of six of the seven Mn II centers in our previously-published cluster [Mn III 12 Mn II 7 (μ4 -O)8 (μ3 -η 1 -N3 )8 (HL Me )12 (MeCN)6 ]Cl2 . Magnetic studies showed that the three Mn III centers in 2 are moderately antiferromagnetically coupled, while the results for 3 allowed an experimental estimate of the Mn III -Mn III coupling in the original [Mn19 ] cluster.