1. Syntheses of High-spin Molecules
H. Oshio
Department of Chemistry, University of Tsukuba, Japan
Workshop on the Quantum Dynamics of Molecular Magnets
December 1 -4, 2002
Awaji Yumebutai International Conference Center

2. Single Molecule Magnets
[Mn(III,IV)12O12(O2CR)16(H2O)] (S = 10) (T. Lis, 1980)
[Mn(III,IV)12O12(O2CR)16(H2O)4]- (S = 19/2)
[Mn(III,IV)4O3X(O2CMe)(dbm)3] (S = 9/2)
[Fe(III)8O2(OH)12(tacn)6]8+ (S = 10)
[V(III)4O2(O2CR)7(L-L)]+ (S = 3)
D. N. Hendrickson, G. Christou, and D. Gatteschi

3. Single Molecule Magnet (SMM)
Hext DE
-Hext
-Hext
Magnetization Direction
DE = |D|Sz2
DE :Energy barrier to reorientate between
two possible directions of magnetizations
D : Zero Field Splitting parameters
SMM

4. Quantum Spin Tunneling
Hext = 0
Tunneling
Hext
No Tunneling

5. Strategy for the High-spin Molecule
Ferromagnetic Interactions by LMCT interactions
AGK Theory P. W. Anderson (1959), J. B. Goodenough (1958), J. Kanamori (1959)

6. Cyanide Bridged Mixed Metal system
[Fe2Cu2(m-CN) 4(bpy) 6] and [Fe2Cu2(m-CN) 4(bpy) 4(Rad) 2]
[FeII2CuII2]
[FeIII2CuII2]
[FeIII2CuII2Rad2] dp dp dp ds ds ds ds ds dp ds dp dp
S = 2
S = 3
S = 1/2x2
Inorg. Chem.

7. Strategy for the High-spin Molecule
Ferromagnetic Interactions by LMCT interactions

8. High-spin Cluster
Orthogonal arrangements
of the magnetic orbitals

9. Bridging Ligands

10. Cu(II) cube of [Cu4(hsae)4]·2H2O
J = 21 cm-1
Monoclinic C2/2
a = (4) Å, b = 9.211(4) Å, c = (4) Å
= 98.23(1)°, V = 4960(2) Å3, Z = 4
R = 0.04, Rw = 0.032
Angew. Chem. Int. Ed. Engl. 1977, 36, 2673.

11. Ni(II) Cube of [Ni4(sae)4(MeOH)4]
Monoclinic P21/c
a = (5) Å, b = (5) Å, c = (8) Å
= (1)°, V = (1) Å3, Z = 2
R1 = , wR2 =
Chem. Lett. 2002, 844.

12. Mn(II) Cube of [Mn4(sap)4(MeOH)4]
g = J = -1.6 cm-1
Tetragonal I41/a
a = (6) Å, c = (16) Å
V = (5) Å3, Z = 4
R1 = , wR2 =
Chem. Lett. 2002, 1016.

13. Fe(II) Cube of [FeII4(sae)4(MeOH)4]
triclinic P1-
a = (7) Å, b = (7) Å, c = (7) Å
= (1)°, b = (1)°, g = (1),
V = (1) Å3, Z = 2
R1 = , wR2 =
J. Am. Chem. Soc

14. AC measurements of [FeII4(sae)4(MeOH)4]

15. Relaxation in [Fe4(sae)4(MeOH)4] with S =8 Ground State
t = t0exp(DE/kT)
t = 1/(2pnAC) nAC : Freq. of AC Field
T : Temp. of max. in c”
DE = |D|S2 = 64|D|

16. Summary Compounds in red are SMM.g C
[emu mol-1 K] 
[K] D
[cm-1] E TB
[Fe4(sap)4(MeO)4]·2H2O
2.261
15.43
9.56
+0.8
[Fe4(5-Br-sap)4(MeO)4]
2.227
14.86
9.32
+0.80
[Fe4(3-MeO-sap)4(MeO)4]·2MeOH
2.243
15.27
12.59
+1.15
[Fe4(sapd)4]·4MeOH·2H2O
2.180
14.29
4.57
+1.10
[Fe4(sae)4(MeO)4]
2.126
15.55
15.98
-0.76 28
1.1
[Fe4(5-Br-sae)4(MeO)4]·MeOH
2.209
14.57
15.68
-0.66 30
1.2
[Fe4(3,5-Cl2-sae)4(MeO)4]
2.120
13.44
13.99
-0.67 26
Compounds in red are SMM.
The g, C, and  values were obtained from temperature dependence of the magnetic susceptibility. D values were estimated by the analyses of magnetization data at 1.8 K, supposing the only S = 8 being populated. E and TB values were estimated from the ac magnetic susceptibility measurements.

17. [FeII6FeIII(5-MeO-saeH)5 (5-MeO-sae)(m3-OMe)6]
7FeCl2·4H2O + 6(5-MeO-saeH2) +
1/21(t-Bu4N)(MnO4) 
m2-phenoxo bridges
S = 29/2 and D = cm-1

18. Summary SMM of Ferrous Cubes
Double Exchange System in a Fe(III)-Fe(II)-Fe(III) System
Multinuclear Mixed Valent Fe(II,III) Systems
Dinuclear Mn(III)-Cu(II) SMM