Syntheses, Crystal Structures, and Magnetic Properties of Two Cyclic Clusters Comprising Six Iron(III)/Manganese(III) Ions and Entrapping Sodium Ions

Abstract

The reaction of iron or manganese salt with sodium 2-{[bis(2-hydroxyethyl)amino]methyl}-4-methylphenate (NaH 2 L) in CH 3 OH/CH 3 CN solution represents a good synthetic route to the cation molecular wheels [NaFe-(III) 6 L 6 ]OH 3 1.5CH 3 CN (1) and [NaMn(III) 6 L 6 ]OH 3 CH 3 OH 3 0.75H 2 O (2), respectively. Single-crystal X-ray diffractions show that six octahedrally coordinated iron(III) ions in 1 and manganese(III) ions in 2 define a ring and are linked by 12 bridging oxygen atoms from alkoxo groups. The resulting [Fe 6 (OCH 2 ) 12 ] or [Mn 6 (OCH 2 ) 12 ] skeleton has the remarkable property of acting as a host for a octahedrally coordinated sodium ion in the center of the ring. DC magnetic susceptibility measurements on complexes 1 and 2 reveal the presence of exchange interactions resulting in a S T =0 or S T =12 ground spin state, respectively. The magnetic behavior of the two clusters indicates antiferromagnetic coupling between the iron(III) centers in 1 and ferromagnetic coupling between the manganese(III) centers in 2.

Synthesis, Structure, and Magnetic Studies of a New Wheel‐Shaped [LiMnIII6] Cluster

“…Axial bonds involve μ 2 ‐oxygen atoms (alkoxo) and nitrogen atoms from L 3– ligands and have unequal lengths with Mn–O from 2.210(3) to 2.238(3) Å and Mn–N from 2.218(4) to 2.226(4) Å. The equatorial sites are occupied by μ 2 ‐oxygen atoms from alkoxo and oxygen atoms from phenoxy with Mn–O from 1.855(3) to 2.010(3) Å, which is in good agreement with the published Mn III 6 ring cluster 11…”

“…General Remarks: The ligand lithium 2‐{[bis(2‐hydroxyethyl)amino]methyl}‐4‐methylphenate (LiH 2 L) was prepared as described previously 11. Other reagents were purchased commercially and used without further purification.…”

“…In 2009, we reported a ferromagnetic complex withNaMn III 6 wheel structure, which was synthesized by the reaction of the quadridentate ligand sodium 2‐{[bis(2‐hydroxyethyl)amino]methyl}‐4‐methyl phenate (NaH 2 L) with manganese salt. It belongs to the first of the above categories 11. To get the similar host‐guest complex, we chose lithium 2‐{[bis(2‐hydroxyethyl) amino]methyl}‐4‐methyl phenate (LiH 2 L) to react with manganese salt and obtained the new cyclic LiMn III 6 cluster, which is reported in this paper.…”

Magnetic Behavior of Heterometallic Wheels Having a [MnIV6M2O9]10+ Core with M = Ca2+ and Sr2+

“…We herein present the synthesis and crystal structure of two wheels with formula [Mn 6 ­M 2 O 9 ­(4- t ­BuC 6 ­H 4 COO) 10 ­(4- t ­BuC 6 ­H 4 COOH) 5 ], where M = Ca 2+ ( 1 ) or Sr 2+ ( 2 ). Several compounds with a Mn 6 wheel-like core have been reported in the literature, showing a wide range of combinations of Mn oxidation states and central ions. − These wheels can be classified in two types: (a) those where the Mn ions are linked through two oxo or oxo derivatives and (b) those where the Mn ions are alternately bridged through one and two oxo or oxo derivatives. Type a wheels prove the versatility of these compounds, which include several Mn z 6 M z ′ x moieties, where z is the Mn oxidation state, M z ′ is the central ion with the z ′ oxidation state, and x is 1 or 2.…”

A 1,2,4‐Triazole‐based Polynuclear Mixed‐valence MnIIMnIII Complex: Synthesis, Characterization, and Magnetic Property

“…A wide variety of manganese complexes containing various remarkable magnetochemical properties have been constructed 1–12. For example, Yang et al described a ferromagnetic coupled S = 12 Mn 6 III wheel by reactions of sodium 2‐{[bis(2‐hydroxyethyl)amino]methyl}‐4‐methylphenate with Mn(acac) 3 3. Furthermore, extensive studies have also been performed on the functional manganese model compounds for mimicking the active site of metalloenzymes such as the water oxidizing complex of photosystem II15–18 and catalase enzymes 13,14…”