Synthesis and Characterization of Mixed‐Valent Manganese Phosphonate Cage Complexes

Abstract

The reaction of phenylphosphonic acid (PhPO(3)H(2)) with the mixed-valent basic oxo-centered manganese triangle [Mn(3)O(O(2)CCMe(3))(6)(py)(3)] (1; where py=pyridine) in the presence of a suitable base gives four different manganese clusters depending on the identity of the base. The syntheses and structural characterization of [Mn(18)(mu(3)-O)(8)(PhPO(3))(14)(O(2)CCMe(3))(12)(py)(6)(H(2)O)(2)] (2), [Mn(7)(mu(3)-O)(3)(O(3)PPh)(3)(O(2)CCMe(3))(8)(py)(3)] (3), [Mn(9)Na(mu(3)-O)(4)(mu(4)-O)(2)(O(3)PPh)(2)(O(2)CCMe(3))(12)(H(2)O)(2)(H(2)O)(0.67)(Py)(0.33)] (4), and [Mn(13)(mu(3)-O)(8)(OMe)(8)(O(3)PPh)(4)(O(2)CCMe(3))(10)] (5) are described. Complexes 4 and 5 are homovalent Mn(III) cages, while 2 and 3 contain divalent, trivalent, and/or tetravalent ions. All the manganese centers are valence-localized, the octahedral Mn(III) sites being recognizable by marked Jahn-Teller distortions. The magnetic properties of compounds 2-5 have been investigated in the polycrystalline state by magnetic susceptibility and high-field magnetization measurements, which reveal that spin ground states vary from 0< or =S > or =8. AC susceptibility measurements performed on 4 and 5, in the 1.6-10.0 K ranges show the presence of out of AC susceptibility signal (chi(M)'') for 4, and an effective energy barrier (U(eff)) for the re-orientation of the magnetization is found to be 17 K, but for 5, the chi(M)'' maximum is found to be below 1.5 K.

Molecular Metal Phosphonates

“…A heterometallic tetranuclear Mn 3 193 This compound was prepared in the reaction of (n-Bu) 4 46 Structural analysis of this compound reveals that the oxo-bridged trinuclear manganese core [Mn 7 198 Interestingly, in this compound the two types of structural motifs described above, the oxocentered Mn 3 Figure 66). 198 A nonanuclear homovalent manganese(III) phosphonate complex, [Mn 9 O 6 (t-BuPO 3 ) 2 (O 2 CMe) 11 (MeCO 2 H)(H 2 O)]· 8H 2 O, is known whose core is shown in Figure 67.…”

“…198 A nonanuclear homovalent manganese(III) phosphonate complex, [Mn 9 O 6 (t-BuPO 3 ) 2 (O 2 CMe) 11 (MeCO 2 H)(H 2 O)]· 8H 2 O, is known whose core is shown in Figure 67. 199 The latter consists of two [Mn 3 O] units linked to a near linear [Mn 3 ] unit by four μ 3 -O ligands.…”

The use of di-2-pyridyl ketone in manganese(II) benzoate chemistry: Two novel linkage isomers containing the ketone form of the ligand and a neutral cubane containing the ligand in its gem-diolate(-1) form

“…Polynuclear manganese carboxylate chemistry is an area of research that has attracted scientists from multi-disciplinary fields including biology [1], material science [2], magnetochemistry [3], physics [4] and synthetic inorganic chemistry [5]. For example, in material science a great number of polynuclear manganese carboxylate complexes have been found to possess large spin ground states [6] and some have also been shown to display the phenomenon of singlemolecule magnetism [7].…”

Synthesis, Crystal Structures, and Magnetic Properties of Lanthanide (III) Amino-Phosphonate Complexes

“…Phosphonic acid and its derivatives are flexible coordination ligands towards a wide range of metal ions, with various ionic radii, including Ln(III) ions, resulting in some materials with promising magnetic properties [8][9][10][11].…”

“…So far, only few 4f-aminophosphonate molecular cages have been reported, the incorporation of the amino group into a phosphonate ligand could provide additional coordination sites for the metal ions and influence the packing of the structures through weak interactions such as hydrogen-bond interactions [8][9][10][11]. The first lanthanide aminophosphonate, Lu(HO3PCH2CH2NH3)3(ClO4)3·3D2O was reported by Legendziwicz et al in 1999 [40,41].…”