TY - JOUR
T1 - Magnetothermal Studies of a Series of Coordination Clusters Built from Ferromagnetically Coupled {(Mn4Mn6III)-Mn-II} Supertetrahedral Units
AU - Nayak, Sanjit
AU - Evangelisti, Marco
AU - Powell, Annie K.
AU - Reedijk, Jan
PY - 2010/11/15
Y1 - 2010/11/15
N2 - Three high-nuclearity mixed valence manganeseII/III coordination
clusters, have been synthesised, that is, [MnIII6MnII4(μ3-O)4(HL1)6(μ3-N3)3(μ3-Br)(Br)](N3)0.7/(Br)0.3⋅3 MeCN⋅2 MeOH
(1) (H3L1=3-methylpentan-1,3,5-triol), [MnIII11MnII6(μ4-O)8(μ3-Cl)4(μ,μ3-O2CMe)2(μ,μ-L2)10Cl2.34(O2CMe)0.66(py)3(MeCN)2]⋅7 MeCN
(2) (H2L2=2,2-dimethyl-1,3-propanediol and py is
pyridine), and [MnIII12MnII7(μ4-O)8(μ3-η1N3)8(HL3)12(MeCN)6]Cl2⋅10 MeOH ⋅MeCN
(3) (H3L3=2,6-bis(hydroxymethyl)-4-methylphenol)
with high ground-spin states, S=22, 28±1, and 83/2, respectively;
their magnetothermal properties have been studied. The three compounds are
based on a common supertetrahedral building block as seen in the Mn10 cluster.
This fundamental magnetic unit is made up of a tetrahedron of MnII ions
with six MnIII ions placed midway along each edge giving an
inscribed octahedron. Thus, the fundamental building unit as represented by
compound 1 can be described as a Mn10 supertetrahedron.
Compounds 2 and 3 correspond to two such
units joined by a common edge or vertex, respectively, resulting in Mn17 and
Mn19 coordination clusters. Magnetothermal studies reveal that
all three compounds show interesting long-range magnetic ordering at low
temperature, originating from negligible magnetic anisotropy of the compounds;
compound 2 shows the largest magnetocaloric effect among the
three compounds. This is as expected and can be attributed to the presence of a
small magnetic anisotropy, and low-lying excited states in compound 2.
AB - Three high-nuclearity mixed valence manganeseII/III coordination
clusters, have been synthesised, that is, [MnIII6MnII4(μ3-O)4(HL1)6(μ3-N3)3(μ3-Br)(Br)](N3)0.7/(Br)0.3⋅3 MeCN⋅2 MeOH
(1) (H3L1=3-methylpentan-1,3,5-triol), [MnIII11MnII6(μ4-O)8(μ3-Cl)4(μ,μ3-O2CMe)2(μ,μ-L2)10Cl2.34(O2CMe)0.66(py)3(MeCN)2]⋅7 MeCN
(2) (H2L2=2,2-dimethyl-1,3-propanediol and py is
pyridine), and [MnIII12MnII7(μ4-O)8(μ3-η1N3)8(HL3)12(MeCN)6]Cl2⋅10 MeOH ⋅MeCN
(3) (H3L3=2,6-bis(hydroxymethyl)-4-methylphenol)
with high ground-spin states, S=22, 28±1, and 83/2, respectively;
their magnetothermal properties have been studied. The three compounds are
based on a common supertetrahedral building block as seen in the Mn10 cluster.
This fundamental magnetic unit is made up of a tetrahedron of MnII ions
with six MnIII ions placed midway along each edge giving an
inscribed octahedron. Thus, the fundamental building unit as represented by
compound 1 can be described as a Mn10 supertetrahedron.
Compounds 2 and 3 correspond to two such
units joined by a common edge or vertex, respectively, resulting in Mn17 and
Mn19 coordination clusters. Magnetothermal studies reveal that
all three compounds show interesting long-range magnetic ordering at low
temperature, originating from negligible magnetic anisotropy of the compounds;
compound 2 shows the largest magnetocaloric effect among the
three compounds. This is as expected and can be attributed to the presence of a
small magnetic anisotropy, and low-lying excited states in compound 2.
U2 - 10.1002/chem.201001988
DO - 10.1002/chem.201001988
M3 - Article (Academic Journal)
SN - 0947-6539
VL - 16
SP - 12865
EP - 12872
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 43
ER -