Supporting Information
Table of Contents
Experimental Section·······················································································S2
Table S1: Crystallographic data and structure refinements for 1 and 2································S5
Table S2: Selected bond lengths and angles of 1 and 2···················································S6
Table S3: Values of corresponding principal axis of 2····················································S7
Table S4: Energies of the lowest spin-orbit states (cm-1) and g tensors of the ground
states ·············································································································S8
Figure S1: Packing diagrams for 1 and 2 ··································································S9
Figure S2: χmT vs T plots for 1, 2 and 1a································································S10
Figure S3: M vs H/T plots for 1 and 2·····································································S11
Figure S4: Temperature dependence ac susceptibility under zero dc field for 1····················S12
Figure S5: Field-dependent ac susceptibility with the ac frequency of 1000 Hz at 2 K for 1·····S13
Figure S6: Frequency and temperature dependence ac susceptibility under 2 kOe dc field for 1·S14
Figure S7: Cole-Cole plots for pure 1 under 2000 Oe dc field········································S15
Figure S8: Relaxation time τ collected on 1 at specified temperatures··························S16
Figure S9: Field-dependent ac susceptibility with frequency of 1000 Hz at 2 K for 2·············S17
Figure S10: χm’’ vs. v under 2000 Oe dc field and 3 Oe ac field for 2··················S18
Figure S11: Temperature dependence ac susceptibility under 2000 Oe dc field for 2··············S19
Figure S12: Cole-Cole plots for 2 under 2000 Oe dc field············································S20
Figure S13: Relaxation time τ collected on 2 at specified temperatures··························S21
Figure S14: The magnetic susceptibility along X rotation for 2·······································S22
Figure S15: The magnetic susceptibility along Y rotation for 2·······································S23
Figure S16: The magnetic susceptibility along Z rotation for 2·······································S24
Figure S17: The magnetization blocking barriers in complexes 1 (a) and 2 (b)·················S25
Figure S18: Electrostatic potential surface of |±6> with (a) and without (b) consideration of π
electrons displacements for 1, magnetic easy axis representation for 1······························S26
Figure S19: Cole-Cole plots for 1a under zero dc field················································S27
Figure S20: Hysteresis for 1a at 2 K······································································S28
Figure S21: Field-dependent ac susceptibility with frequency of 1000 Hz at 2 K for 1a·········S29
Figure S22: χm’’ vs. v under 1000 Oe dc field for 1a········································S30
Figure S23: Cole-Cole plots for 1a under 1000 Oe·····················································S31
Figure S24: χm’’ vs. v under zero dc field for 2a··············································S32
Experimental Section
S1
The synthesis of air and/or moisture sensitive compounds was carried out under
an atmosphere of argon using Schlenk techniques or in a Argon filled glovebox.
THF was dried in solvent purification system, transferred under vacuum, and
stored in the glovebox. Cyclooctatetraene (COT) was degassed after dried over
activated 4 Å molecular sieves overnight. [(COT)LnCl(THF)](Ln = Tm, Y) were
prepared according to literature procedures.1 Unless otherwise noted, all starting
materials were commercially available and were used without further purification.
Elemental analysis was performed by Elementar Vario MICRO CUBE (Germany).
The ICP analysis was performed by Inductively Coupled Plasma-Atomic
Emission Spectrometer designed by Leeman company.
[(Tp)Tm(COT)] 1: A THF solution (10 mL) of TpK (168.9 mg, 0.70 mmol) was
slowly added to the slurry of [(COT)TmCl(THF)] (250 mg, 0.67 mmol) in THF
and stirred overnight. The solution was filtered and concentrated to 3 mL, and left
unperturbed to allow the slow evaporation of the solvent. Yellow single crystals
were obtained suitable for X-ray diffraction analysis after several days. Yield: 124
mg. Anal. Calcd (%) for C17H18BN6Tm: C, 42.00; H, 3.73; N, 17.28. Found: C,
42.06; H, 3.91; N, 17.55.
[(Tp*)Tm(COT)] 2: Following the procedure described for 1. The reaction of
[(COT)TmCl(THF)] (250 mg, 0.67 mmol) with Tp*K (225 mg, 0.69 mmol) gave
orange-red crystals. Yield: 76 mg. Anal. Calcd (%) for C23H30BN6Tm: C, 48.44;
H, 5.30; N, 14.73. Found: C, 48.13; H, 5.33; N, 14.59.
[(Tp)Tm0.05Y0.95(COT)] 1a: The [(COT)TmCl(THF)] and [(COT)YCl(THF)]
were mixed in 5:95 molar ratio, and followed by the same procedure of 1. Light
yellow crystal was obtained for X-ray diffraction analysis. The space group is
P212121. The Unit cell dimension is a=7.3481(2) Å, b=13.1972(4) Å,
c=18.3906(5) Å, V=1783.42(9) Å3. The final ratio is determined by both the dc
susceptibility measurement and ICP. The magnetic experiment gives the molar
ratio of 5.6 : 94.4, which is accordance with the original ratio. The amount of
TmIII (5.5 %) is also confirmed by the ICP analysis.
S2
[(Tp*)Tm0.05Y0.95(COT)] 2a: Follow the method of 1a. light red crystal was
obtained for X-ray diffraction analysis. The space group is P1. The Unit cell
dimension is a= 10.2863(2) Å, b= 10.4698(2) Å, c= 12.6171(3) Å, α=
100.0961(18), β= 105.5608(19) γ = 112.539(2)V= 1143.96(4) Å3. The amount of
TmIII (4.3 %) is found by the ICP analysis.
X-ray crystallography and magnetic measurement
All crystals were manipulated under a nitrogen atmosphere and were covered in
grease. Data collections were performed at 180 K on a Aglient technologies Super
Nova Atlas Dual System, with a (Mo Kα= 0.71073 Å) microfocus source and
focusing multilayer mirror optics. The structures were solved by direct methods
and refined with the full-matrix least-squares technique based on F2 using the
SHELXL program. All non-hydrogen atoms were refined anisotropically.
Hydrogen atom on B atom was located from the difference Fourier maps. Other
hydrogen atoms were placed at the calculation positions.
Samples were fixed by eicosane to avoid moving during measurement and
sealed in the glass tube to avoid reaction with moisture and oxygen. Direct current
susceptibility experiment was performed on Quantum Design MPMS XL-5
SQUID
magnetometer
on
polycrystalline
sample.
Alternative
current
susceptibility measurement with frequencies ranging from 100 to 10000 Hz was
performed on Quantum Design PPMS and ranging from 1 to 1000 Hz was
performed on Quantum Design MPMS-XL5 SQUID magnetometer on
polycrystalline sample. All dc susceptibilities were corrected for diamagnetic
contribution from the sample holder, eicosane and diamagnetic contributions from
the molecule using the pascal’s constants.
Angular-resolved magnetometry measurement was performed using Quantum
Design horizontal rotator. The faces of suitable single crystal of 2 were indexed
on a Aglient technologies Super Nova Atlas Dual System. The experimental
Cartesian coordinates XYZ were defined as below. We define the crystallographic
b axis parallel to X axis, and the normal of (101) face parallel to Z axis. The
S3
crystal was fixed using N grease on the plate of the rotator. Then we performed
the rotation measurement along defined XYZ axes under applied 0.2 T dc field.
As the mass of the sample can be obtained with required accuracy, we compared
the mass from balance and the density product volume. All data were corrected
for the diamagnetic contribution from the grease and rotator.
Ab initio calculations
Complete-active-space self-consistent field (CASSCF) calculations on the
complete structures of complexes 1 and 2 on the basis of X-ray determined
geometry have been carried out with MOLCAS 7.8 program package. For
CASSCF calculations, the basis sets for all atoms are atomic natural orbitals from
the MOLCAS ANO-RCC library: ANO-RCC-VTZP for TmIII ion; VTZ for close
C and N; VDZ for distant atoms. The calculations employed the second order
Douglas-Kroll-Hess Hamiltonian, where scalar relativistic contractions were
taken into account in the basis set and the spin-orbit coupling was handled
separately in the restricted active space state interaction (RASSI-SO) procedure.
The active electrons in 7 active spaces included all f electrons (CAS(12 in 7)) in
the CASSCF calculation. To exclude all the doubts we calculated all the roots in
the active space. We have mixed all of the possible spin-free states (all from 21
triplets; all from 28 singlets).
References
1) H. Schumann, R. D. Koehn, F. W. Reier, A. Dietrich and J. Pickardt, Organometallics,
1989, 8, 1388.
S4
Table S1 Crystallographic data and structure refinements for 1 and 2.
formula
1
2
Mr
cryst syst
space group
a, Å
b, Å
c, Å
V, Å3
α, deg
β, deg
γ, deg
Z
T, K
μ, mm−1
λ, Å
Cryst size, mm3
GOF
Rint
R1, wR2[I >2σ(I)]
R1, wR2[all data]
486.11
orthorhombic
P 212121
7.3442(1)
13.1951(3)
18.2376(4)
1767.36(6)
90
90
90
4
180(2)
5.031
0.71073
0.30*0.30*0.15
1.063
0.0626
0.0366, 0.0871
0.0432, 0.0920
570.27
triclinic
P1
10.2525(3)
10.4225(3)
12.6063(4)
1138.94(6)
99.828(3)
105.686(3)
112.582(3)
2
180(2)
3.917
0.71073
0.20*0.20*0.10
1.079
0.0459
0.0251, 0.0511
0.0311, 0.0544
S5
Table S2 Selected bond lengths and angles of 1 and 2.
1
2
Tm–N(1), Å
2.386(4)
2.493(2)
Tm–N(2), Å
2.380(5)
2.442(3)
Tm–N(3), Å
2.390(5)
2.485(3)
Tm–C(COT), Å
2.54(1)~2.55(1)
2.544(7)~2.602(9)
Tm–centroid of COT, Å
1.7592(2)
1.7969(1)
Tm–centroid of N(1, 2, 3)
1.6222(2)
1.6496
∠N(1)-Tm-N(2)
79.8(1)°
76.8(1)°
∠N(2)-Tm-N(3)
77.5(1)°
75.9(1)°
∠N(3)-Tm-N(1)
79.2(1)°
88.3(1)°
∠B-Tm-centroid of COT
179.1(9)°
173.265(2)°
S6
Table S3 Values of corresponding principal axis of 2.
T/K
χzz
χxx
χyy
1.9
2
2.5
3
3.5
4
4.5
5
6
7
8
9
10
11
13
15
20
7.42422
7.05425
5.80495
4.90634
4.22916
3.70433
3.31803
2.99038
2.50375
2.15645
1.89577
1.68207
1.51857
1.38058
1.16743
1.01124
0.75589
0.19432
0.20297
0.14223
0.11366
0.09807
0.0871
0.08191
0.08495
0.06352
0.05354
0.04924
0.04433
0.04094
0.03996
0.03488
0.03049
0.02418
0.09876
0.09929
0.07507
0.05799
0.0535
0.04592
0.03911
0.05774
0.0317
0.03148
0.02794
0.02619
0.0243
0.02174
0.01944
0.01837
0.01567
S7
Table S4 Energies of the lowest spin-orbit states (cm-1) and g tensors of the ground
states
1
2
Energies of the lowest spin-orbit states (cm-1)
1
0
0
2
0.012
0.023
3
394.736
406.519
4
414.117
409.444
5
430.085
477.967
6
448.022
493.356
7
456.837
538.069
8
508.773
566.838
9
519.278
590.420
10
541.641
605.767
11
589.816
623.524
12
601.413
647.466
13
604.540
654.709
g tensor of the ground state
gx
0.000
0.000
gy
0.000
0.000
gz
13.964
13.959
S8
(a)
(b)
Figure S1 Packing diagram for 1 and 2 shown along the crystallographic a axis.
Color code: grey, carbon; blue, nitrogen; yellow, boron; pink, thulium. H atoms
have been omitted for clarity.
S9
Figure S2 Temperature dependence of the dc magnetic susceptibility times
temperature for 1 and 2 under 1000 Oe applied dc magnetic field. Inset: χmT vs T
plots for 1 and 1a.
S10
(a)
(b)
Figure S3 M vs H/T plots for 1 (a) and 2 (b).
S11
Figure S4 Temperature dependence ac susceptibility under zero dc field for 1.
S12
Figure S5 Field-dependent ac susceptibility with the ac frequency of 1000 Hz at 2
K for 1.
S13
a)
b)
Figure S6 a) Frequency-dependent ac susceptibility under 2 kOe dc field for 1
collected on MPMS-XL5 from 1 Hz to 1000 Hz; b) Temperature-dependent ac
susceptibility under 2 kOe dc field for 1 collected on PPMS from 100 Hz to
10000 Hz.
S14
a)
b)
Figure S7 a) Cole-Cole plots fit for the determination of the temperature
dependence of τ for pure 1 under 2000 Oe dc field on MPMS-XL5 from 4 K to 17
K; b) Cole-Cole plots fit for the determination of the temperature dependence of τ
for pure 1 under 2000 Oe dc field on PPMS from 7 K to 30 K. Solid lines
represent the results of fitting to a generalized Debye model.
S15
Figure S8 Relaxation time τ collected on 1 at specified temperatures under
different dc fields from 0 to 2000 Oe.
S16
Figure S9 Field-dependent ac susceptibility with frequency of 1000 Hz at 2 K for
2.
S17
a)
b)
Figure S10 a) Out-of-phase (χm’’) signal vs. frequency (v) plots under 2000 Oe dc
field and 3 Oe ac field on MPMS-XL5 for 2; b) Out-of-phase (χm’’) signal vs.
frequency (v) plots under 2000 Oe dc field and 3 Oe ac field on PPMS for 2.
S18
Figure S11 Temperature dependence ac susceptibility under 2000 Oe dc field for
2.
S19
a)
b)
Figure S12 a) Cole-Cole plots fit for the determination of the temperature
dependence of τ for 2 under 2000 Oe dc field from 2 K to 11 K on MPMS-XL5; b)
Cole-Cole plots fit for the determination of the temperature dependence of τ for 2
under 2000 Oe dc field from 5 K to 20 K on PPMS. Solid lines represent the
results of fitting to a generalized Debye model.
S20
Figure S13 Relaxation time τ collected on 2 at specified temperatures under
applied dc fields from 0 to 5000 Oe.
S21
Figure S14 The magnetic susceptibility along X rotation for 2.
S22
Figure S15 The magnetic susceptibility along Y rotation for 2.
S23
Figure S16 The magnetic susceptibility along Z rotation 2.
S24
Figure S17 The magnetization blocking barriers in complexes 1 (a) and 2 (b).
The thick black lines represent the non-Kramers doublets as a function of their
magnetic moment along the magnetic axis. The green lines correspond to
diagonal quantum tunneling of magnetization (QTM); the blue line represents
Orbach relaxation process. The numbers at each arrow stand for the mean
absolute value of the corresponding matrix element of transition magnetic
moment. The path shown by the red arrows represents the most probable path for
magnetic relaxation in the corresponding compounds.
S25
Figure S18 Electrostatic potential surface of |±6> with (a) and without (b)
consideration of π electrons displacements for 1. Magnetic easy axis orientations (c)
determined by CASSCF calculations (green) and the electrostatic model (blue),
respectively.
S26
Figure S19 Cole-Cole plots fit for the determination of the temperature
dependence of τ for 1a under zero dc field from 2 K to 16 K. Solid lines represent
the results of fitting to a generalized Debye model.
S27
Figure. S20 Hysteresis experiment under the field scanning rate of 1.9 mT/s for
1a.
S28
Figure. S21 Field-dependent ac susceptibility with frequency of 1000 Hz at 2 K
for 1a.
S29
Figure S22 Out-of-phase (χm’’) signal vs. frequency (v) plots under 1000 Oe dc
field and 3 Oe ac field for 1a from 7 K to 27 K.
S30
Figure S23 Cole-Cole plots fit for the determination of the temperature
dependence of τ for 1a under 1000 Oe from 10 K to 27 K. Solid lines represent
the results of fitting to a generalized Debye model.
S31
Figure S24 Out-of-phase (χm’’) signal vs. frequency (v) plots under zero dc field
and 3 Oe ac field for magnetic diluted 2(2a) from 2 K to 22 K.
S32