Synthesis of anS_T= 7 [Mn₃] Mixed-Valence Complex Based on 1,3-Propanediol Ligand Derivatives and Its One-Dimensional Assemblies

Abstract

Controlled organization of high-spin complexes and single-molecule magnets is a great challenge in molecular magnetism in order to study the effect of the intercomplex magnetic interactions on the intrinsic properties of a given magnetic object. In this work, a new S(T) = 7 trinuclear mixed-valence Mn complex, [Mn(III)Mn(II)2(LA)2(Br)4(CH3OH)6] ·Br·(CH3OH)(1.5)·(H2O)(0.5) (1), is reported using a pyridinium-functionalized 1,3-propanediol ligand (H2L(A)Br = 1-(3-bromo-2,2-bis(hydroxymethyl)propyl)pyridinium bromide). Using azido anions as bridging ligands and different pyridinium-functionalized 1,3-propanediol ligands (H2L(B)Br = 1-(3-bromo-2,2-bis(hydroxymethyl)propyl)-4-picolinium bromide; H2L(C)Br = 1-(3-bromo-2,2-bis(hydroxymethyl)propyl)-3,5-lutidinium bromide), the linear [Mn(III)Mn(II)2L2X4](+) building block has been assembled into one-dimensional coordination networks: [Mn(III)Mn(II)2(LA)2(Br)4(CH3OH)4(N3)]·((C2H5)2O)1.25 (2∞), [Mn(III)Mn(II)2(L(B))2(Br)4(C2H5OH)(CH3OH)(H2O)2(N3)]·(H2O)0.25 (3∞), and [Mn(III)Mn(II)2(L(C))2(Cl)(3.8)(Br)(0.2)(C2H5OH)3(CH3OH)(N3)] (4∞). The syntheses, characterization, crystal structures, and magnetic properties of these new [Mn3]-based materials are reported.

Self-assembly of linear [MnII2MnIII] units with end-on azido bridges: the construction of a ferromagnetic chain using ST = 7 high-spin trimers

“…11.75 cm 3 K mol −1 for S Mn(III) = 2, S Mn(II) = 5/2 and g Mn(III) = g Mn(II) = 2), indicating ferromagnetic interactions in both compounds. Ac susceptibility measurements were performed below 15 K and shown the complete absence of outphase signal above 1.8 K, which is coincident with the previously reported Mn 3 trimer with similar linear [Mn II -Mn III -Mn II ] motif, 6,9 indicating the negligible magnetic anisotropy in 1. For 1, χT increases gradually and exhibit a broad peak with a maximum of 26.4 cm 3 K mol −1 at 14 K, corresponding to the S T = 7 ground state for isolated [Mn II 2 Mn III ] unit.…”

“…10 In order to fit the lower temperature data, mean field approximation zJ'' that describes the inter-chain magnetic interactions and temperature-independent paramagnetism (TIP), were also added to the model. 6 Weak ferromagnetic coupling between Mn II ions is anticipated through end-on azido bridges as the Mn-N-Mn bridge angles are appreciably less than 104°, 11 an angle that separates the ferro-and antiferro-magnetic interactions in end-on bridged azido system. The estimation of the intratrimer Mn II ···Mn III interaction (J 1 ) is in excellent agreement with our previously results.…”

“…1 These efforts could enhance the intrinsic SMM properties and provide a unique opportunity to investigate new magnetic behaviors at the frontier between SMMs and long-range magnetic ordered materials. 6 Layered or tubular aggregates also can be obtained from sulfamide functionalized 1,3-diol ligands and dicyanamide bridges. 3 On the other hand, linking SMMs into one-dimensional (1D) chain system through coordination bonds could generate single-chain magnets (SCMs), a new class of magnetic materials with Ising-type magnetic anisotropy and strong intrachain magnetic interactions.…”

“…Through modifications on the backbone group of diol ligands, such high spin building units can be assembled into 1D chains through end-to-end azido bridges, with fine control over the alignment of the neighbouring Mn III Jahn-Teller axes. 6 Layered or tubular aggregates also can be obtained from sulfamide functionalized 1,3-diol ligands and dicyanamide bridges. 7 Although the intratrimer ferromagnetic interactions and the S T = 7 spin ground state of the [Mn II 2 Mn III ] cluster were preserved during the self-assembling, magnetic interactions between [Mn II 2 Mn III ] units are usually antiferromagnetic, which somewhat prohibits the observation of more exciting magnetic behaviours such as SCM or long range magnetic ordering at higher temperatures.…”

Synthesis, Structure, and Magnetic Properties of a Mn4 Cluster derived from Benzimidazole‐Alcohol Ligands

“…In the development of new synthesis routes, the selection of the organic ligands is extremely significant. Many ligands have been explored for the formation of 3d metal clusters with various topologies and magnetic properties, such as alcohol amines,17 pyridyl alcohols,18 pyridyl ketone oximes,19 salicylaldoximes,20 alkyl alcohols,21 aromatic alcohols,22 and so on 23,24…”