DyIIIsingle-molecule magnets from ligands incorporating both amine and acylhydrazine Schiff base groups: The centrosymmetric {Dy2} displaying dual magnetic relaxation behaviors

Article abstract of DOI:10.1039/c9dt04434e

The novel multidentate chelating ligands N′-(2-pyridylmethylidene)-2-(2-pyridylmethylideneamino)benzohydrazide (Hpphz) and N′-(2-salicylmethylidene)-2-(2-salicylmethylideneamino)benzohydrazide (H3sshz), which incorporate both amine and acylhydrazine Schiff base groups, were synthesized and investigated in DyIII coordination chemistry. The reactions of Hpphz and Dy(OAc)3·4H2O have yielded two {Dy2} featuring double OAc- bridges: [Dy2(H2aphz)2(OAc)4(ROH)2] [R = Me (1) and Et (2)], where the Hpphz ligands were in situ hydrolyzed into 2-amino-(2-pyridylmethylideneamino)benzohydrazide ions (H2aphz-). Besides, the reaction between H3sshz and Dy(NO)3·6H2O afforded a [Dy6(sshz)4(μ3-OH)4(μ4-O)(MeOH)4]2·17.5MeOH·2H2O cluster (3). This cluster contained two discrete {Dy6} cores, each of which consisted of a pair of {Dy3} triangular units. All the complexes displayed a single relaxation process of single-molecule magnet (SMM) behaviors under a zero dc field. Both 1 and 2 showed field-induced dual magnetic-relaxation behaviors. However, their diluted samples (1?Y and 2?Y) only showed one-step relaxation behaviors whether under a zero or applied dc field, indicating that the dual magnetic-relaxation behaviors of 1 and 2 were absent after the dilution. Combined with ab initio calculations, it could be infered that the dual magnetic-relaxation behaviors of 1 and 2 might be ascribled to the joint contributions of the single ion anisotropy and magnetic interactions. Examples of this type are rather rare in previous studies. Ab initio calculations also suggested that the discrepancy between the relaxation processes of 1 and 2 may be caused by the small difference between their magnetic interactions.

Full text of DOI:10.1039/c9dt04434e

View Article Online
View Journal
Dalton
Transactions
An international journal of inorganic chemistry
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: S. Su, J. Li, F. Xu,
C. Wang, K. Wang, Y. Li, S. Zhang, X. Zhang, Y. Zhang and F. Liang, Dalton Trans., 2020, DOI:
10.1039/C9DT04434E.
Volume 46
Number 10
14 March 2017
Pages 3073-3412
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Dalton
Transactions
An international journal of inorganic chemistry
Accepted Manuscripts are published online shortly after acceptance,
before technical editing, formatting and proof reading. Using this free
rsc.li/dalton
service, authors can make their results available to the community, in
citable form, before we publish the edited article. We will replace this
Accepted Manuscript with the edited and formatted Advance Article as
soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes to the
text and/or graphics, which may alter content. The journal’s standard
Terms & Conditions and the Ethical guidelines still apply. In no event
ISSN 0306-0012
COMMUNICATION
Douglas W. Stephen et al.
shall the Royal Society of Chemistry be held responsible for any errors
N-Heterocyclic carbene stabilized parent sulfenyl, selenenyl,
and tellurenyl cations (XH+, X = S, Se, Te)
or omissions in this Accepted Manuscript or any consequences arising
from the use of any information it contains.
rsc.li/dalton

Please do not adjust margins
Page 1 of 12
Dalton Transactions
View Article Online
DOI: 10.1039/C9DT04434E
ARTICLE
DyIII single-molecule magnets from ligands incorporating both
amine and acylhydrazine Schiff base groups: the centrosymmetric
{Dy2} displaying dual magnetic relaxation behaviors
Received 00th January 20xx,
Accepted 00th January 20xx
Sen-Da Su,a Jia-Xin Li,b Fan Xu,a Chen-Xiao Wang,a Kai Wang,*a Yan Li,a Shu-Hua Zhang,a Xiu-Qing
Zhang,a Yi-Quan Zhang*b and Fu-Pei Liang*a
DOI: 10.1039/x0xx00000x
Novel multidentate chelating ligands N′-(2-pyridylmethylidene)-2-(2-pyridylmethylideneamino)benzohydrazide (Hpphz) and
N′-(2-salicylmethylidene)-2-(2-salicylmethylideneamino)benzohydrazide (H3sshz), which incorporate both amine and
acylhydrazine Schiff base groups, were synthesized and investigated in DyIII coordination chemistry. The reactions of Hpphz
and Dy(OAc)3·4H2O have yielded two {Dy2} featuring double OAc- bridges: [Dy2(H2aphz)2(OAc)4(ROH)2] [R = Me (1) and Et (2)],
where the Hpphz ligands were in situ hydrolyzed into 2-amino-(2-pyridylmethylideneamino)benzohydrazide ions (H2aphz-).
While the reaction between H3sshz and Dy(NO)3·6H2O afforded a [Dy6(sshz)4(μ3-OH)4(μ4-O)(MeOH)4]2·17.5MeOH·2H2O
cluster (3). It contains two discrete {Dy6} cores, each of which consists of a pair of {Dy3} triangle units. All complexes display
single relaxation process of single-molecule magnet (SMM) behaviors under zero dc field. Both 1 and 2 show field-induced
dual magnetic relaxation behaviors. However, their diluted samples (1@Y and 2@Y) only show one-step relaxation behaviors
whether under zero or applied dc field, that the dual magnetic relaxation behaviors of 1 and 2 are absent after the dilution.
Combined with ab initio calculations, it could be infered that the dual magnetic relaxation behaviors of 1 and 2 might be
ascribled to the joint contributions of the single ion anisotropy and magnetic interactions. The cases of this type were rather
rare in previous studies. Ab initio calculations also suggest that the discrepancy between relaxation processes of 1 and 2
may be caused by small difference between their magntic interactions.
family of {Ln2}-SMMs with the highest Tb to 20 K.5 Winpenny group
has reported a {Dy5}-SMM. Its DyIII ions arranging in square-based
pyramidal fashion define a strong uniaxial magnetic anisotropy,
giving a high Ueff of 528 K.6 Nevertheless, there are remain huge
difficulties in tuning the single ion anisotropy, magnetic interactions
and arrangements of the spins simultaneously.7 This resulted in the
fact, that the well behaved di- and poly-nuclear Dy-SMMs are still
limited relative to those of mononuclear. In this regard, continuous
efforts should be devoted to novel di- and poly-nuclear systems,
whose potential is not yet fully explored.
Introduction
Lanthanide SMMs that can be potentially applied in ultra-high
density information storage, quantum computing and molecular
spintronics, are of increasing attentions in recently years.1 Especially
the Dy complexes have shown to be their ideal candidates, due to
the intrinsic Kramers doublet ground state and magnetic anisotropy
of the Dy(III) ion.2 By optimizing the single-ion anisotropy according
to symmetry strategy, great advances with growing records of
efficient energy barrier (Ueff) and blocking temperatures (Tb) have
been achieved in mononuclear Dy-SMMs.3 Note that the DyIII···DyIII
magnetic interactions and the spatial arrangements of the DyIII ions
within di- and poly-nuclear systems, are also contributing factors for
high SMM performace.4 For instances, utilizing radical-bridges that
could transmit strong magnetic exchanges to suppress quantum
tunnelling of magnetization (QTM), Long et. al. have deveploped a
The magnetic relaxation processes of Dy-SMMs is another issue
deserving attentions in this field. One of the most attracting type is
those bearing dual relaxation behaviors. It is true that the
illumination of their complicated relaxation mechanisms remains
one of the challenges for researchers. But in turn, they afford ideal
models to probe various factors on the relaxation besides the single-
ion anisotropy, which thus can give pointed guidances to tuning the
performaces.8 Based on previous studies, several inducements for
dual relaxation behaviors have been proposed for Dy-SMMs with
different structural characteristics.9 The most common, by far, is that
the DyIII centers locate in inequivalent ligand fields and have different
single-ion behavior.10 Beyond that, the effects of the hyperfine
interactions between nuclear spins and total angular momentum,11
and the intermolecular interactions12 were also demonstrated. It is
significant that the intramolecular magnetic interactions were found
a. Address here. Guangxi Key Laboratory of Electrochemical and Magnetochemical
Functional Materials, College of Chemistry and Bioengineering, Guilin University of
Technology, Guilin, 541004, China.
E-mail: fliangoffice@yahoo.com; kaiwang2011@yahoo.com
b. Address here. Jiangsu Key Lab for NSLSCS, School of Physical Science and
Technology, Nanjing Normal University, Nanjing 210023, China.
E-mail: zhangyiquan@njnu.edu.cn
† Footnotes relating to the title and/or authors should appear here.
Electronic Supplementary Information (ESI) available: [details of any supplementary
information available should be included here]. See DOI: 10.1039/x0xx00000x
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 2 of 12
ARTICLE
Journal Name
to induce distinct dual relaxation behaviors in minority of Dy-SMMs
whose DyIII centers locate in identical ligand fields.13 These cases are
precious, as it is usually confusing to distinguish the contributions of
the single-ion anisotropy and intramolecular magnetic interactions
on the relaxation in most of the Dy-SMMs.14 The studies on them
would help to map the synergic effects between single-ion
anisotropy and magnetic interactions on the SMM performances.
View Article Online
DOI: 10.1039/C9DT04434E
NH2
Ln(OAc)3
N
NH
N
N
N
O
O
In suit
hydrolysis
N
N
N
H2aphz-
Hpphz
Scheme 2 The formation of H2aphz- from hydrolysis of the Hpphz.
Whether for the togopogies, relaxation processes or performancs
of the Dy-SMMs, the key roles of the ligands are self-evident. Among
various ligands, aimine and acylhydrazine Schiff bases have been
wildly favoured by the researches, respectively. They supply strong
coordination fields and suitable multichelating pockets for DyIII ions,
having good abilities to assemble di- and poly-nuclear SMMs with
novel topologies.15 Moreover, the O-donors of these ligands, could
either form strong coordination bonds with the DyIII ions to generate
their single axial magnetic anisotropy,16 or act as the magnetic
bridges to reinforce the DyIII···DyIII interactions efficiently.17 Typical
cases include amine Schiff base which yielded serise of {Dy2}-SMMs
with the highest Ueff of 110 K,18 amine Schiff base coupling two {Dy3}
triangles into a {Dy6}-SMM for maximizing the toroidal moment,19
and acylhydrazine Schiff base that assembled a {Dy2}-SMM with dual
relaxation processes and two high Ueff of 150 and 198 K,20 etc.
Surprisingly, the ligand incorporating both amine and acylhydrazine
Schiff base groups was scarely employed in this field, albeit the
synergism of two kinds of groups affords considerable possibility to
achieve fantistic products. So far, to the best of our knowledge, only
one ligand of this type has been investigated, which has constructed
serise of {Mn2Ln4} clusters featuring chair-shaped core.21
Complexes 1 and 2 were synthesized by the same solvothermal
reactions of Hpphz ligand and Ln(OAc)3·4H2O in the presence of
triethylamine, just differ depending on the solvents. It is noteworthy
that the H2aphz- ligands formed in situ, through the hydrolysis of
amine Schiff bases group of the Hpphz ligand (Scheme 2). This could
be supported by the change of IR spectrum between the ligand and
the complexes (Figure S1). After the coordiantion, the strong
absorption band of 1651 cm−1 for –C=N– stretching of amine Schiff
base group disappeared. New bands near 3605 and 1579 cm−1 that
could be assigned to the stretching and bending vibrations of the
resultant –NH2 group can be observed. However, this in situ
hydrolysis didn’t happened during the formation of 3, which was
obtained by the solvothermal reaction of H3sshz ligands and
Ln(NO3)3·6H2O. In this regard, it could be speculated that either the
OAc- ions or the Py terminal group might be responsible for the
hydrolysis of the of the Hpphz ligands in 1 and 2. On the other hand,
there is one of commonalities for the IR spectrum of 1-3, that the
characteritic bands near 1565 cm−1 belonging to the –N=C(OH)–
group could be found. It suggests that the acylhydrazone groups of
the ligands in 1-3 all coordianted in enol forms.
On account of above and based on our previous work,22 we started
to investigate the potential of the ligands containing both amine and
acylhydrazine Schiff base sites. Novel ligands of Hpphz and H3sshz
featuring this structure were disigned and synthesized (Scheme 1).
Their reactions with DyIII salts afforded two {Dy2} (1 and 2) and a {Dy6}
(3) complexes, all of which were found to show one-step magnetic
relaxation under zero field. Field induced dual relaxation behaviors
are evident in 1 and 2, which were seldomly seen in symmetrical
{Dy2} systems. Combined with magnetic dilution and ab initio
calculations, the relationships among the molecular structures,
single-ion magnetism, magnetic interactions, relaxation processes
and the SMM properties of 1-3 have been discussed.
The thermogravimetric (TG) analyses of 1-3 are presented in
Figure S2. Complexes 1 and 2 display very similar TG behaviors. In the
temperature range of 25 to 160 °C, they undergo a weight loss of
6.0% (calcd 5.8% for 1) and 8.0% (calcd 8.1% for 2), respectively,
which agree well with the losing of two coordinated solvent
molecules. Free lattice solvent molecules of 3 lost in the temperature
range of 25-181 °C with a weight loss of 9.3% (calc. 9.9%). Upon
further heating, all complexes suffered continuous weight losses
until final decomposition to metal oxides. In addition, their
experimental power X-ray diffraction (PXRD) curves match well with
the simulated profiles derived from corresponding crystal data
(Figure S3), respectively. These results indicate the purities of their
samples.
Structural analysis
N
NH
N
N
NH
N
Single-crystal X-ray diffraction data revealed that 1 crystallizes in the
O
O
OH
N
1
triclinic space group P . As shown in Figure 1a, its centrosymmetric
HO
N
structure consists of two DyIII ions, four OAc- ions, two H2aphz-
ligands and two MeOH molecules. A pair of OAc- ions chelate to two
Dy centers, respectively. While another pair of OAc- ions adopt an μ2-
η1:η2 bridging mode, by which two DyIII centers are double-bridged
to form a [Dy2(OAc)2] core (Figure 1b). All atoms of this core are
almostly co-planar, with a least square value of 0.043. The Dy⋯Dy
H3sshz
Hpphz
Scheme 1 The Hpphz and H3sshz ligands used in this work.
Results and discussion
Syntheses and Characterization
⁰
distance is 4.157 Å and the Dy-O-Dy angle is 112.890 . Inspection of
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
the C7–O1 bond length (1.312(1) Å), the charge balance calculation Namine and Nhydrazine [N1−H2a···N2 = 2.013(1) Å]. Two hydrogen bonds
View Article Online
and above IR analysis confirm that two H2aphz- ligands were involved between the OMeOH and Oenol [O6−H6a···O1 = 1.923(1) Å] were also
DOI: 10.1039/C9DT04434E
found, which help to reinforce the [Dy2(OAc)2] core. However, no
significant intermolecular interaction was found. The smallest
Dy···Dy distance between the adjacent molecules is about 9.438 Å.
(a)
(b)
1
Complex 2 also crystallizes in triclinic P space group and displays
112.890⁰
very similar centrosymmetric structure to that of 1, except that
terminal coordinated MeOH were replaced by EtOH (Figure S4). This
difference has induced tiny change of the average Dy-O and Dy-N
bond lengthes, Dy⋯Dy distances and Dy-O-Dy angles from 1 to 2
(Table 1). It further resulted a structural dissimilarity, that the
geometry of DyIII center of 1 is capped square antiprism, while that
of 2 is tricapped trigonal prism (Table S2).
O6
N4
O4a
N3a
O3
Dy1a
O2a
4.157 Å
O2
Dy1
O3a
O5
O5a
(c)
N3
O4
N4a
O6a
O1
Dy1
Table 1 A summery of detailed structural parameters of 1 and 2.
Spherical capped square antiprism
Complexes
1
2
Figure 1. Molecular structure (a), [Dy2(OAc)2] core (b) and
coordination geometry of the DyIII ions of 1.
Average Dy-O bond lengthes (Å)
Average Dy-N bond lengthes (Å)
Dy⋯Dy distances (Å)
2.430(3)
2.535(3)
4.157(3)
112.898(1)
2.431(3)
2.530(4)
4.167(4)
112.300(1)
in the coordination in enol forms. Each of them chelates a Dy ion with
a [NON] pocket of acylhydrazone group, playing the role of terminal
ligand along with two MeOH moleclues. In this way, each Dy center
locates in a coordination environment consisting of five Oacetate, an
Oenol, an OMeOH and two Nhydrazine donors (Figure 1c). The Dy-O and the
Dy-N bond lengths are in the range of 2.165(5)-2.465(7) and 2.165(5)-
2.465(7) Å, respectively. Continuous symmetry measure (CShM)
method was employed to analyze exact coordination geometry of
the DyIII ion using SHAPE2.1 software.23 The lowest CShM parameters
indicat that the geometry of DyIII center belongs to spherical capped
square antiprism with a C4v symmetry (Table S1).
Dy-O-Dy angles (⁰)
capped square tricapped
antiprism trigonal prism
Geometries of DyIII centers
Complex 3 belongs to the monoclinic space group P21/n. Its
components per formular unit contains two discrete {Dy6} clusters
(3a and 3b), together with several free MeOH and H2O molecules.
The main difference of two {Dy6} clusters is that the directions of
coordinated MeOH molecules are unidentical (Figure S5). However,
they still display almost the same topologies. For brevity, only the
structure of 3a will be described in detail.
Cluster 3a consists of six DyIII ions, four sshz3- ligands, an μ4-O2- ion,
four μ3-OH- ions and four temerinal coordinated MeOH molecules
(Figure 2a). Its skeleton could be regarded as the linkup of two
There are two kinds of intramolecular hydrogen bonds in 1. The -
NH2 group in each H2aphz- ligand inverses to the other side of the
acylhydrazone pockets, generating a hydrogen bond between the
(b)
(d)
O10
Dy1
Dy2
O11
O13
O4
O5
O2
Dy4
O3
O6
(a)
O1
Dy6
Dy5
O12
Dy3
O15
O7
Dy1/Dy3: Square antiprism
Dy2/Dy4: Triangular
dodecahedron
O14
(c)
(e)
Dy5: Triangular
dodecahedron
Dy6: Square antiprism
μ3-1:1:2:1:2
Figure 2 Molecular structure (a), {Dy6} core (b), coordination mode of the ligand (c), and geometries (d and e) of the DyIII ions of 3a.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 4 of 12
ARTICLE
Journal Name
triangle {Dy3} units (Figure 2b), each of which was assmebled by a the magnetization increases smoothly without saturaVtiieownAertvicelenOanltin7e
III
DOI: 10.1039/C9DT04434E
pairs of μ3-Ohydroxyl (O4 and O5 or O12 and O13). Trideprotonated T, which is most likely due to the anisotropy of the Dy ions and
crystal-field effects.25 Furthermore, the absence of the superposition
of M-HT-1 curves also indicate the presence of significant magnetic
anisotropy and/or low-lying excited states in these systems.26
ligands sshz3− all show an μ3-1:1:2:1:2 binding mode (Figure 2c).
On one hand, they contribute their μ-Oenol (O3, O6, O11 and O14) to
bridge the adjacent DyIII ions, further reinforcing each triangle unit.
On the other hand, four μ-Ophenol (O2, O7, O10 and O15) of them link
two {Dy3} triangle units together in an edge-to-edge fashion with the
help of an μ4-O2- ion (O1), giving rise to the {Dy6} core of 3a. The
average Dy···Dy separation and Dy···Dy···Dy angle are 3.525 Å and
60.000⁰, respectively. The dihedral angle between two meaning
planes of {Dy3} units is 49.738(1)º.
All DyIII ions in 3a are eight-coordinated and could be divided into
two types in terms of their donors. The donors of the Dy1, Dy2, Dy3
or Dy4 include two Ophenol, two Ohydroxyl, an Oenol, a Nhydrazine, an μ4-O
and an OMeOH (Figure 2d). And the Dy5 or Dy6 coordinate with two
Ophenol, two Ohydroxyl, two Oenol and two Nimine (Figure 2e). The bond
lengths of Dy-O and Dy-N are in the ranges of 2.234(1)-2.466(1) and
2.462(1)-2.555(2) Å, respectively. Calculated lowest CShM valuses
demonstrate that the geometries of Dy1/Dy3/Dy6 are distorted
square antiprismatic, while those of Dy2/Dy4/Dy5 are distorted
triangular dodecahedron (Table S3).
Dynamic Magnetic Properties
In order to investigate the dynamic magnetic behaviors of 1-3, the
alternating current (ac) magnetic susceptibility measurements were
performed at frequency range of 1-1000 Hz. In the absence of a dc
field, clear frequency dependence of out-of-phase (χ′′) signals
relating with single magnetic relaxation process could be observed
for both 1 and 2 (Figure 4a and 4b), indicative of typical SMM
behaviors. Their ac susceptibilities were fitted according to
generalized Debye model, affording Cole-Cole plots where most of
the curves display asymmetric semicircles (Figure 4c and 4d). The
ranges of the distribution coefficients α for 1 and 2 are 0.03-0.22 and
0.02-0.30 (Table S4 and S5), respectively, which reveal relatively
narrow distribution of their relaxation times.
The extracted τ of 1 and 2 all obey the Arrhenius law as Eq. 1 in
high-temperature range (Figure 4e and 4f, green lines), all
corresponding to the Orbach process.
Magnetic studies
τ = τ0exp(Ueff/kBT)
(1)
Static Magnetic Properties
As the temperature decreased, the τ values of 1 and 2 diverge from
the Arrhenius law gradually. This might be attributed to the existence
of the Raman, direct and QTM relaxation processes. Thus, their data
over entire temperature range was fitted with Eq. 2 (Figure 4e and
4f, red lines),
Variable-temperature dc magnetic susceptibilities of 1-3 were
measured in the temperature range of 300-2 K under an applied field
of 1 kOe. As shown in Figure 3, the χMT values at 300 K for 1-3 are
28.02, 28.01 and 85.30 cm3 mol-1 K, respectively, being close to their
corresponding theoretical values calculated from two or six free DyIII
ions (6H15/2, g = 4/3). Upon cooling, the χMT values of three all
decrease slowly up to about 15 K, which then decline sharply to the
minimum values at 2 K. These results might be attributed to the weak
antiferromagnetic interactions between the DyIII centers and/or the
thermal depopulation of Stark sublevels of the DyIII centers in the
systems.24
-1
-1
τobs-1 = τ0 exp(-Ueff/kBT) + AT + CTn + τQTM
(2)
where the τ0-1exp(Ueff/kBT), AT, CTn and τQTM-1 account for Orbach,
direct, Raman and QTM processes, respectively. The best fittings of
above give Ueff = 59 K, τ0 = 2.75 × 10-6 s, A = 96.29 K-1 s-1 and τQTM
= 0.0018 s for 1; Ueff = 59 K, τ0 = 2.94 × 10-6 s and τQTM = 0.0005 s
for 2
.
The field dependence of the magnetization measured at different
temperature for 1-3 were plotted as M-H (Figure 3 inset) and M-HT-
1 curves (Figure S6). The M-H curves of all three show a rapid increase
at low magnetic fields. Upon further increasing of the applied field,
Aiming to impress the QTM effect on the magnetic relaxation, the
ac susceptibilities of 1 and 2 were further measured under optimum
dc fields, which were determined to be 1 kOe for both systems
(a)
(c)
(b)
84
78
72
66
60
54
3
2
1
27
24
21
18
27
24
21
18
12
9
12
10
8
32
24
16
8



N
N
N
6
6
2.0 K
2.5 K
5.0 K
10 K
2.0 K
2.5 K
5.0 K
10 K
2.0 K
2.5 K
5.0 K
10 K
M
M
M
4
3
T
2
T
T

0
0
0


0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
H / T
H / T
H / T
0
50 100 150 200 250 300
0
50 100 150 200 250 300
0
50 100 150 200 250 300
T / K
T / K
T / K
Figure 3 The plots of χM-T and M-H (inset) under different temperatures for 1-3.
Please do not adjust margins

Page 5 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
(e)
(a)
(c)
View Article Online
DOI: 10.1039/C9DT04434E
3.2
-6.5
-7.0
-7.5
-8.0
-8.5
-9.0
12.0 K
Hdc = 0 Oe
2.0 K
3.0
2.4
1.8
1.2
0.6
0.0
1
1
1
Hdc = 0 Oe
Hdc = 0 Oe
2.4
1.6
0.8
0.0
12.0 K
2.0 K

Orbach
Orbach + Direct + QTM


1
10
100
1000
0
2
4
6
8
10
0.1
0.2
0.3
-1 / K-1
0.4
0.5
' / cm3 mol-1
v / Hz
T
(b)
(d)
(f)
3.0
2.4
1.8
1.2
0.6
0.0
-7.2
-7.5
-7.8
-8.1
-8.4
-8.7
12.0 K
Hdc = 0 Oe
2.0 K
2
2
2
2.4
1.6
0.8
0.0
Hdc = 0 Oe
Hdc = 0 Oe
12.0 K
2.0 K


Orbach
Orbach + Direct + QTM

2
4
6
8
10
1
10
100
1000
0.1
0.2
0.3
T-1 / K-1
0.4
0.5
' / cm3 mol-1
v / Hz
Figure 4 Frequency-dependent χ″ ac susceptibilities, Cole-Cole and lnτ-T-1 plots for 1 and 2 under zero dc field
.
(Figure S8). Corresponding χ″ signals of 1 and 2 all show two well- relaxation behaviors could be further verified by the Cole−Cole plots
resolved peaks in low temperature region, suggesting the existence (Figure 5c and 5d), which display consecutive double-semicircle
of two-step relaxation processes (Figure 5a and 5b). When the shapes at low temperatures. Accordingly, the data was fitted by the
temperature increases, the low-frequency peak intensities decline sum of two modified Debye functions (Eq 3) as following:28
and only high frequency peaks are observed. These imply that there
∆휒1
∆휒2
are evolutions from the fast relaxation (FR) to the slow relaxation
(SR) with improvements of the temperature.27 The two-step
휒ac(휔) = 휒S,tot
+
+
)
1
(
3)
(
1 ― 훼
(1 ― 훼 )
2
(
)
(
)
1 + 푖휔휏1
1 + 푖휔휏2
(e)
(a)
(c)
12.0 K
2.0 K
1
-3
1
1
1.2
0.8
0.4
0.0
1.2
0.8
0.4
0.0
Hdc = 1 kOe
Hdc = 1 kOe
-4
-5
-6
-7
-8
-9
Orbach for SR
Orbach + Roman for SR
Orbach for FR


12.0 K
Hdc = 1 kOe
2.0 K
1
10
100
1000
1.5
2
3.0
4.5
6.0
7.5
9.0
0.1
0.2
0.3
0.4
0.5
' / cm3 mol-1
T -1 / K-1
v / Hz
(b)
(d)
(f)
12.0 K
2.0 K
1.2
0.9
0.6
0.3
0.0
2
2
-4
-6
-8
1.2
0.8
0.4
0.0
Hdc = 1 kOe
Hdc = 1 kOe
Orabch of SR
Orabch + Roman of SR
Orabch of FR

12.0 K
2.0 K

Hdc = 1 kOe
1
10
100
1000
2
4
6
8
10
0.1
0.2
0.3
T -1 / K-1
0.4
0.5
' / cm3 mol-1
v / Hz
Figure 5 Frequency-dependent χ″ ac susceptibilities, Cole-Cole and lnτ-T-1 plots for 1 and 2 under 1 kOe dc fields
.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 6 of 12
ARTICLE
Journal Name
The best fitting gives the αFR and αSR parameters of 1 in the range (Figure S10). As shown in Figure 7a and 7b, samples 1@Y and 2@Y
View Article Online
DOI: 10.1039/C9DT04434E
of 0.15−0.38 and 0.06−0.38, respectively (Table S6), both of which still present one-step relaxation behaviors under 0.4 kOe dc fields.
The χ″ signals all show clear peaks, and shift to lower frequency range
relative to those under zero field. Meanwhile, the lack of overlapping
peak maxima at low temperatures imply that the QTM have been
supressed efficiently under the optimized dc field. The Cole−Cole
plots show approximate semicircles (Figure 7c and 7d), from which
the fitting afford α values in the range of 0.14-0.49 for 1@Y and 0.25-
0.47 for 2@Y (Table S10 and S11). These results further confirm the
single relaxation behaviors of 1@Y and 2@Y. Fitting of the lnτ vs. T-1
data to Eq 2 led to Ueff = 60 K, τ0 = 1.0 × 10-5 s, A = 0.65 K-1 s-1, C =
are comparable to those of 2 (0.03  αFR  0.37 and 0.03  αSR  0.39;
Table S7). These results reveal that the distribution of relaxation
times for both systems under optimum dc fields are narrow. For the
SR, the plots of lnτ vs. T−1 were fitted well with Eq 2 (Figure 5e and
5f), respectively, affording the following parameters: Ueff = 52 K, τ0
6.80 × 10-6 s, C =16.20 s-1 K-0.35 and n = 0.35 for 1; Ueff = 52 K, τ0
=
=
5.97 × 10-6 s, C = 31.98 s-1 K-0.51 and n = 0.51 for 2. However, the
plots of lnτ vs. T−1 for FR of 1 and 2 only obey the Arrhenius law as
Eq. 1, which give Ueff = 3.7 K and τ0 = 1.86 × 10-4 s for 1, Ueff = 0.5 K
and τ0 = 2.40 × 10-4 s for 2.
5.60 × 10−4 s−1 K−6.83 and n = 6.83 for 1@Y (Figure 7e)
τ0 = 5.2 × 10-6 s, A = 2.26 K-1 s-1, C = 1.25 × 10−3 s−1 K−6.48 and n =
6.48 for 2@Y (Figure 7f)
; Ueff = 51 K,
In order to make insights into the two steps magnetic relaxation
behaviors of 1 and 2, the ac susceptibilities of their diluted samples
(1@Y and 2@Y) were further investigated. Under zero field, both
1@Y and 2@Y show one-step relaxation behaviors as 1 and 2. In
comparison with those of 1 and 2, however, their maxima χ″ peaks
shift to higher frequency region, and the χ″ peaks for the QTM
process become more incomplete and widened (Figure 6a and 6b).
Accordingly, the arcs of their Cole−Cole curves become less
asymmetric (Figures 6c and 6d). Fitting of the Cole–Cole plots afford
α values in the ranges of 0.14-0.49 for 1@Y and 0.25-0.47 for 2@Y
(Table S8 and S9). Treating the data of lnτ vs. T−1 with Eq 2 give
following sets of parameters: Ueff = 62 K, τ0 = 2.57 × 10-7 s and τQTM
= 0.0005 s for 1@Y (Figure 6e); Ueff = 63 K, τ0 = 6.51 × 10-8 s and
τQTM = 0.0003 s for 2@Y (Figure 6f). These results suggest that the
QTM in 1@Y and 2@Y is suppressed but not completely quenched.24
In this case, the ac susceptibilities of 1@Y and 2@Y were further
recorded under applied dc field, which was optimized to be 0.4 kOe
.
As for 3, its χ″ susceptibilities show obvious frequency-dependent
peaks under zero field, indicating the slow relaxation of
magnetization in association with SMM properties (Figure 8 a). Semi-
circular shapes are observed in its Cole-Cole diagrams (Figure 8 c).
The fitting with generalized Debye model provides the α values in the
range of 0.03-0.23 (Table S12), which suggests a narrow distribution
for the relaxation time. The lnτ vs. T-1 only obey the Arrhenius law as
Eq. 1 (Figure 8e), affording Ueff = 14 K and τ0 = 1.23 × 10-5
s. When
an optimum dc fields of 2 kOe was applied (Figure S12), the
temperature range where the χ″ peaks could be identified became
much wider than that under zero dc field (Figure 8b), and the Cole-
Cole plots show more symmetric arcs (Figure 8d). The simulation
gives α values from 0.21 to 0.32 (Table S13). The lnτ vs. T-1 curve is
nonlinear at whole temperatures. Fitting to Eq 2 afforded Ueff = 15 K,
τ0 = 4.36 × 10−5 s, C = 4.36 s-1 K-2.39 and n = 2.39 (Figure 8f)
.
(e)
(a)
(c)
12.0 K
1.8 K
1@Y
1@Y
0.2
0.1
0.0
0.2
0.1
0.0
Hdc = 0 Oe
-8.0
-8.8
-9.6
1@Y
Hdc = 0 Oe
Hdc = 0 Oe
12.0 K
1.8 K



0.1
0.2
0.3
0.4
0.5
0.6
0.2
0.4
0.6
0.8
1.0
1
10
100
1000
T -1 / K-1
' / cm3 mol-1
v / Hz
(b)
(d)
(f)
-8
-9
0.3
0.2
0.1
0.0
0.3
0.2
0.1
0.0
12.0 K
1.8 K
2@Y
Hdc = 0 Oe
2@Y
Hdc = 0 Oe
2@Y
Hdc = 0 Oe
12.0 K
1.8 K
-10
-11
-12



0.3
0.6
0.9
1.2
1.5
0.1
0.2
0.3
0.4
0.5
0.6
1
10
100
1000
' / cm3 mol-1
T -1 / K-1
v / Hz
Figure 6 Frequency-dependent χ″ ac susceptibilities, Cole-Cole plots and lnτ-T-1 plots under zero dc field for 1@Y and 2@Y.
Please do not adjust margins

Page 7 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
(e)
(a)
(c)
View Article Online
DOI: 10.1039/C9DT04434E
0.4
0
-2
1@Y
Hdc = 0.4 kOe
1@Y
Hdc = 0.4 kOe
1@Y
Hdc = 0.4 kOe
0.3
0.2
0.1
0.0
0.3
0.2
0.1
0.0
12.0 K
1.8 K
12.0 K
1.8 K
-4

-6

-8

-10
0.0
0.2
0.4
0.6
0.1
0.2
0.3
-1 / K-1
0.4
0.5
0.6
1
10
100
1000
' / cm3 mol-1
T
v / Hz
(b)
(d)
(f)
0.4
0.3
0.2
0.1
0.0
0.4
0.3
0.2
0.1
0.0
2@Y
Hdc = 0.4 kOe
2@Y
Hdc = 0.4 kOe
2@Y
Hdc = 0.4 kOe
-2
-4
-6
-8
12.0 K
1.8 K
12.0 K
1.8 K



1
10
100
1000
0.0
0.2
0.4
0.6
0.8
0.1
0.2
0.3
0.4
0.5
0.6
' / cm3 mol-1
T
-1 / K-1
v / Hz
Figure 7 Frequency-dependent χ″ ac susceptibilities, Cole-Cole diagrams and lnτ-T-1 plots for 1@Y and 2@Y under 0.4 kOe dc fields
.
(e)
(a)
(c)
8
6
4
2
0
8
6
4
2
0
-6.3
-7.0
-7.7
-8.4
10.0 K
2.0 K
10.0 K
2.0 K
3
3
3
Hdc = 0 Oe
Hdc = 0 Oe
Hdc = 0 Oe


Orbach
0.48
1
10
100
1000
10.0 K
5
10
15
20
25
30
0.30
0.36
T -1 / K-1
0.42
' / cm3 mol-1
v / Hz
(b)
(d)
(f)
5
4
3
2
1
0
5
4
3
2
1
0
2.0 K
10.0 K
2.0 K
3
3
3
-5
-6
-7
-8
-9
Hdc = 2 kOe
Hdc = 2 kOe
H
dc = 2 kOe


Orbach
Orbach + Roman
1
10
100
1000
4
8
12
16
0.1
0.2
0.3
T -1 / K-1
0.4
0.5
' / cm3 mol-1
v / Hz
Figure 8 Frequency-dependent χ″ ac susceptibilities, Cole-Cole plots and lnτ-T-1 plots for 3 under zero and 2 kOe dc fields
.
tensors and the predominant mJ values of the lowest eight Kramers
doublets (KDs) for each DyIII fragment are list in Table S14, where the
3a_Dy1 and 3a_Dy5 possess the smallest (33.8 cm-1) and the largest
(214.6 cm-1) energy gaps between the lowest two KDs, respectively.
The calculated gx and gy values for 1_Dy1 are close to the
corresponding values of 2_Dy1, which show that 1 and 2 have almost
the same transverse anisotropy components. The predominant mJ
Theoretical Calculations
The calculations using complete-active-space self-consistent field
(CASSCF) on individual DyIII fragments (Figure S13) of 1−3 derived
from single-crystal structures have been conducted with MOLCAS
8.429 and SINGLE_ANISO programs (see the Supporting Information
for computational details).30 The energy levels (cm−1), g (gx, gy and gz)
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 7
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 8 of 12
ARTICLE
Journal Name
components for the lowest two KDs of each single-DyIII moiety show
In the family of these {Dy2}-SMMs, the dual relaxation behaviors
View Article Online
III
DOI: 10.1039/C9DT04434E
that their ground KDs are all mostly composed by mJ = ±15/2 state generally occurred in those asymmetric systems that two Dy ions
(Table S15). Their first excited states are also mostly composed by locate in inequivalent sites,10 and could be ascribed to different
several mJ states severely, apart from those of the 3a_Dy5, 3a_Dy6 single-ion magnetism relating to weak exchange limit.32 Obviously,
and 3b_Dy6 being all mostly composed by mJ = ±13/2. From the different single-ion magnetism of two DyIII centers should not be the
magnetization blocking barriers of individual DyIII fragments (Figure inducement for dual relaxation behaviors of 1 and 2 featuring
S14), it could be found that the transversal magnetic moments in the centrosymmetric structures. From above ac susceptibilities data, it is
ground states of the 3a_Dy5, 3a_Dy6, 3b_Dy5 and 3a_Dy4, 3b_Dy3, clearly observed that both 1@Y and 2@Y show single relaxation
3b_Dy6 are about 10-3 and 10-3 µB, respectively. These results behavior not only under zero field but also under applied dc field. In
indicate that the QTMs in their ground states could be suppressed at other word, the dual relaxation behaviors of 1 and 2 are absent along
low temperature. On the other hand, the transversal magnetic with the weaken/vanishment of the magnetic interactions after the
moments in the first excited states of 1−3 are mostly about 10-1 µB, dilution. It is thus suggested that the dual relaxation behaviors of 1
therefore resulting in fast QTM in their first excited KDs.
and 2 might be related with the magnetic interactions in the systems.
Similar cases can also be found in previous literature. For instances,
Tang group has stated that the presence of two relaxation processes
in a {Dy2}-SMM might be ascribed to the weak intramolecular
exchange and dipolar interactions.13c Ho and Chibotaru have proved
that the existence of a sufficiently wide dipolar field distribution is
the main cause for the appearance/disappearance of the multiple
maxima in magnetic relaxation processes.33 Within 1 and 2, the
magnetic interactions are dominated by those of intramolecular as
indicated by above theoretical calculation. However, the
contributions of the intermolecular interactions on the relaxation
processes of 1 and 2 might still exist, though they all show rather
small values coupling constants. Because even when two Dy ion
reside far away from each other, the dipolar coupling between each
other may affect the magnetic properties of the systems.33,34
Therefore, the intramolecular and intermolecular magnetic
interactions, as well as the single ion anisotropy of Dy ions, might
jointly contribute to the dual relaxation behaviors of 1 and 2.
Despite the magnetic anisotropies of the lanthanide SMMs mainly
stem from the individual DyIII fragments, the DyIII···DyIII interactions
have non-negligible influence on their slow magnetic relaxation
processes. Thus, the DyIII···DyIII interactions of 1 and 2 were further
investigated. Considering the results that the calculated ground gz
values for their single-DyIII moieties are all near 20 (Table S14), the
DyIII···DyIII interactions were treated as Ising type in simulations. In
this premise, the program of POLY_ANISO30 was applied to simulate
the magnetic susceptibilities. Relevant intramolecular magnetic
interaction parameters (Table 2) include the total coupling
parameter Jtotal, its components of the exchange coupling (Jexch) and
dipole−dipole interaction (Jdip), all of which were fitted with respect
to a pseudospin (S%) of 1/2 on the DyIII sites. The intermolecular
interactions were also considered in the fitting. Relevant
intermolecular coupling constants between the nearest DyIII ions of
1 and 2 are 0.006 and −0.048 cm−1, respectively (Table S16).
Table 2. Fitted Jexch, Jdip and the Jtotal between magnetic center ions in
1 and 2 (cm−1).
On the other hand, the theoretical calculation has also shown
some difference between the magnetic interactions of 1 and 2, which
should be induced by substitution of coordinated solvent molecules.
These results confirm the previous reports that the magnetic
interactions in {Dy2}-SMMs can be tuned through subtle structural
variations not only in the aspect of the bridging factors, but the
terminal coordinated groups. For examples, Wang et. al has reported
Complexes
Jexch
0.50
0.25
Jdip
Jtotal
1
2
−2.15
−2.06
−1.65
−1.81
The experimental and calculated χMT-T plots of 1 and 2 are shown
together in Figure S15. Two sets of data for each system are close to
each other. The fitted results within the Lines model31 indicate that
the intramolecular interactions Jtotal and Jdip are all antiferromagnetic,
while the exchange couplings Jexch of 1 and 2 are ferromagnetic (Table
2). And the Jtotal primarily depend on Jdip, as the calculated values of
Jdip all overcome corresponding values of Jexch. Between 1 and 2,
there is no obvious difference no matter for the Jtotal or Jdip values.
However, the Jexch value for 1 (0.50 cm-1) is just twice as large as that
of 2 (0.25 cm-1).
a
transition between antiferromagnetic and ferromagnetic
interaction states when terminal coordinated dimethylacetamide
(DMA) were changed to dimethylformamide (DMF),35 Murugesu et.
al suggested that the dipolar and exchange components of the
magnetic interactions could be turned by the dihedral angle of the
terminal amido ligands,10a and so on. Given the calculated results
that 1 and 2 have negligible dissimilarity between their single ion
anisotropy of individual DyIII fragments, the tiny change of the
magnetic interactions could also be regarded as the possible reason
for the discrepancy between their relaxation processes.
In addition, the exchange energies, the energy differences
between each exchange doublets Δt and the main values of the gz for
the lowest two and four exchange doublets of 1 and 2 were also
calculated (Table S17). Their gz values of the ground-state exchanges
are all 0.000. This further confirms the antiferromagnetic DyIII···DyIII
interactions in both systems. The main magnetic axes were also
drawn on the DyIII ions for 1 and 2, respectively, where the magnetic
axes for both complexes are all antiparallel (Figure S16).
Experimental section
Syntheses of the Hpphz and H3sshz ligands
A solution of 2-amino-benzohydrazide (10 mmol) in an anhydrous
EtOH was added to a solution of pyridine-2-aldehyde or salicyl-
aldehyde (20 mmol) in an anhydrous EtOH (Scheme S1). The reaction
8 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 9 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
mixture was stirred and refluxed for 3 h. Upon cooling to room Synthesis of 3
View Article Online
DOI: 10.1039/C9DT04434E
temperature, yellowish needle-like crystals were obtained. Then the
crystals were collected by filtration and recrystallized with EtOH,
giving Hpphz or H3sshz ligands, respectively.
A mixture of Dy(NO3)3·6H2O (0.15 mmol), H3sshz (0.1 mmol) and 7
drops of triethylamine in 7 mL MeOH solvent was sealed in a Teflon-
lined stainless autoclave after stirring for several minutes. The
1
Hpphz: Yield: ca. 83%. H NMR (d6-DMSO, δ/ppm): 8.67 (s, 1H), autoclave was heated to 80 °C for 72 h followed by cooling to room
8.59 (d, J = 4.5 Hz, 1H), 8.48 (d, J = 4.1 Hz, 1H), 7.99 (d, J = 3.3 Hz, 1H), temperature at a rate of 0.5 °C min−1. Yellowish crystals of 3 suitable
7.91-7.92 (m, 1H), 7.79-7.88 (m, 2H), 7.74 (dd, J = 7.8, 1.2 Hz, 1H), for X-ray diffraction analysis were obtained.
7.46 (d, J = 7.9 Hz, 1H), 7.39-7.42 (m, 1H), 7.26-7.32 (m, 2H), 6.79 (d,
[Dy6(sshz)4(μ4-O)(μ3-OH)4(CH3OH)4]2∙17.5MeOH∙2H2O (3). Yield:
J = 8.1 Hz, 1H), 6.76-6.70 (m, 1H), 6.67 (d, J = 3.4 Hz, 1H). Elemental
analyses (%) calcd for C19H15N5O: C, 69.29; H, 4.59; N, 21.26. Found:
C, 69.35; H, 4.39; N, 21.12. Selected IR (KBr, cm−1): 3348(s), 1660(m),
1576(s), 1504(s), 1447(s), 1364(s), 1255(w), 1158(m), 1058(m),
1013(w), 959(w), 931(w), 874(w), 758(m), 679(m), 529(m), 413(m).
29% (based on the H3sshz ligand). Elemental analysis (%) calcd. for
C193.5H226Dy12N24 O61.5: C, 39.92, H, 3.91, N, 5.77; found: C, 40.12, H,
3.78, N, 5.87. Selected IR (KBr, cm−1): 3394 (m), 3152 (m), 1605(s),
1528 (s), 1472 (m), 1443 (m), 1394 (m), 1345 (m), 1197 (w), 1181 (w),
1152 (w), 755 (m).
1
H3sshz: Yield: ca. 79%. H NMR (d6-DMSO, δ/ppm): 11.45 (s, 1H),
Materials and general methods
10.24 (s, 1H), 8.46 (s, 1H), 7.81 (d, J = 6.8 Hz, 1H), 7.49 (d, J = 2.3 Hz,
1H), 7.40 (dd, J = 7.7, 1.4 Hz, 1H), 7.32-7.27 (m, 2H), 7.15-7.12 (m,
1H), 6.99 (d, J = 7.6 Hz, 1H), 6.93-6.83 (m, 5H), 6.76 (t, J = 7.5 Hz, 1H),
6.70 (t, J = 7.5 Hz, 1H). Elemental analyses (%) calcd for C21H17N3O3:
C, 70.18; H, 4.77; N, 11.69. Found: C, 70.30; H, 4.65; N, 11.52.
Selected IR (KBr, cm−1): 3369(s), 3188(s), 1643(s), 1614(s), 1491(s),
1456(m), 1405(s), 1405(s), 1365(m), 1273(w), 1236(m), 1155(s),
1097(m), 962(m), 754(s), 694(w), 650(w), 588(w), 526(w), 476(w).
All reagents were used as received without further purification. IR
spectra were taken on
a Perkin-Elmer spectrum One FT-IR
spectrometer in 4000~400 cm-1 region with KBr pellets. Elemental
analyses for C, H and N were carried out on a Model 2400 II, Perkin-
Elmer elemental analyzer. NMR spectra were obtained on BRUKER
Ascend-500. Thermal analyses were performed on a Netzsch STA
449C thermal analyzer from room temperature at a heating rate of
10C min-1 under a continuous stream of N2. Powder X-ray diffraction
(PXRD) patterns were recorded using Cu-Kα radiation on PANalytical
X’Pert PRO diffractometer. Energy dispersive spectroscope (EDS)
were measured using field emission scanning electron microscopy
(SEM, HITACHI, SU5000).
Syntheses of 1 and 2
A mixture of Dy(OAc)3·4H2O (0.2 mmol), Hpphz (0.1 mmol) and 5
drops of triethylamine in 7 mL MeOH solvent was sealed in a Teflon-
lined stainless autoclave after stirring for several minutes. The
autoclave was heated to 60 °C for 48 h followed by cooling to room
temperature at a rate of 0.5 °C min−1. Yellowish crystals of 1 suitable
for X-ray diffraction analysis were obtained.
Magnetic measurements
The magnetic susceptibility measurements were carried out on a
Quantum Design SQUID magnetometer MPMS-XL 7 operating
between 2.0 and 300 K for dc-applied fields ranging from 0-7 T.
Polycrystalline samples were dispersed in Vaseline in order to avoid
torquing of the crystallites. The sample mulls were contained in a
calibrated gelatine capsule held at the centre of a drinking straw that
was fixed at the end of the sample rod. Alternating current (ac)
susceptibility measurements were carried out under an oscillating ac
field of 3.5 Oe and frequencies ranging from 1 to 1000 Hz using both
zero and optimized static dc fields.
The preparation of 2 followed the same procedure as 1, except
that the solvent was EtOH.
[Dy2(H2aphz)2(OAc)4(MeOH)2] (1). Yield: 32% (based on the Hpphz
ligand). Elemental analysis (%) calcd. for C36H42Dy2N8O12: C, 39.17, H,
3.83, N, 10.15; found: C, 39.31, H, 3.94, N, 10.33. Selected IR (KBr,
cm−1): 3614 (s), 3348 (s), 1576 (s), 1504 (s), 1446 (s), 1364 (s), 1255
(w), 1157 (m), 1058 (m), 758 (m), 678 (m).
[Dy2(H2aphz)2(OAc)4(EtOH)2] (2). Yield: 29% (based on the Hpphz
ligand). Elemental analysis (%) calcd. for C38H46Dy2N8O12: C, 40.33, H,
4.10, N, 9.90; found: C, 40.87, H, 4.21, N, 10.15. Selected IR (KBr,
Crystallographic refinement and structure solution
cm−1): 3615 (s), 3348 (s), 1573 (s), 1502 (s), 1443 (s), 1365 (s), 1255 All the data were collected with an Agilent Supernova diffractometer
(w), 1154 (m), 1057 (m), 755 (m), 680 (m).
by using graphite monochromatic Mo-Kα radiation (λ = 0.71073 Å) at
298.15 K (150.00 K for 3). Absorption effect was corrected by semi-
empirical methods. The structures were solved by direct methods
and were refined by full-matrix least-squares methods with a suite of
SHELX programs via the Olex2 interface.36 The non-hydrogen atoms
were refined anisotropically. The hydrogen atoms were placed in
calculated positions and refined by using a riding model. The final
cycle of full-matrix least-squares refinement was based on observed
reflections and variable parameters. ORTEP-style drawings showing
ADPs of 1-3 are provide in Figure S18-S20. The detailed parameters
for the structures are shown in Table S19. The related structural data
such as bond lengths and angles for 1-3 are presented in Tables S20-
Preparation of diluted samples of 1 and 2.
The diluted samples 1@Y and 2@Y were synthesized as the same
method of 1 and 2, respectively, except that the Dy(OAc)3·4H2O was
substituted with a mixture of Dy(OAc)3·4H2O and Y(OAc)3·4H2O with
a molar ratio of 1:9. The purity of the diluted samples was confirmed
by a comparison between the experimental PXRD pattern and those
simulated from the single-crystal data (Figure S3). The contents of
DyIII and YIII in the final crystalline products were 10.83% and 89.07%
for 1@Y as well as 8.38% and 91.62% for 2@Y, which were
determined by energy dispersive spectroscope (EDS) of field-
emission scanning electron microscope (Table S18).
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 9
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 10 of 12
ARTICLE
Journal Name
S22, respectively. CCDC 1964713-1964715 for 1-3, respectively, can
be obtained from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif, which is free of charge.
6
7
8
9
R. J. Blagg, C. A. Muryn, E. J. L. McInnes, F. Tuna, R and E. P.
DOI: 10.1039/C9DT04434E
Winpenny, Angew. Chem. Int. Ed., 2011, 50, 6530.
L. Zhang, Y. Q. Zhang, P. Zhang, L. Zhao, M. Guo and J. K. Tang.
Inorg. Chem., 2017, 56, 7882.
K. Katoh, Y. Aizawa, T. Morita, B. K. Breedlove and M.
Yamashita, Chem. Eur. J., 2017, 23, 15377.
View Article Online
Conclusions
In summary, by employing novel ligands incorporating both amine
and acylhydrazine Schiff base groups, a pair of {Dy2} (1 and 2) and a
{Dy6} (3) SMMs have been prepared. They all display one-step slow
relaxation processes under zero dc field. Both 1 and 2 were further
found to show distinct dual relaxation behaviors when 1 kOe dc field
were applied. However, the dual relaxation behaviors were not
observed in their diluted samples whether under zero or applied dc
field. Given these facts and combined with ab initio calculation, it
could be inferred that the synergism between the single ion
anisotropy and magnetic interactions might be the inducement for
their dual relaxation behaviors. Moreover, the change of
coordinated solvent molecules between 1 and 2 has induced tiny
difference of the magnetic interactions, as indicated by theoretical
calculations. This might be responsible for the discrepancy between
the relaxation processes of 1 and 2. This work thus demonstrates the
potential of ligands incorporating both amine and acylhydrazine
Schiff base groups in the achievement of novel di- and poly-nuclear
Dy-SMMs, and provides new insight for the dual relaxation behaviors
of the Dy-SMMs.
M. Ren, L. M. Zheng, Acta Chim. Sinica, 2015, 73, 1091.
10 (a) Y. N. Guo, G. F. Xu, W. Wernsdorfer, L. Ungur, Y. Guo, J. K.
Tang, H. J. Zhang, L. F. Chibotaru and A. K. Powell, J. Am. Chem.
Soc., 2011, 133, 11948; (b) K. L. M. Harriman, J. J. L. Roy, L.
Ungur, R. J. Holmberg, I. Korobkova and M. Murugesu, Chem.
Sci., 2017, 8, 231; (c) I. F. Díaz-Ortega, J. M. Herrera, D.
Aravena, E. Ruiz, T. Gupta, G. Rajaraman, H. Nojiri and E.
Colacio, Inorg. Chem., 2018, 57, 6362.
11 F. Pointillart, K. Bernot, S. Golhen, B. Le Guennic, T. Guizouarn,
L. Ouahab and O. Cador, Angew. Chem. Int. Ed., 2015, 54,
1504.
12 (a) M. Jeletic, P. H. Lin, J. J. Le Roy, I. Korobkov, S. I. Gorelsky
and M. Murugesu, J. Am. Chem. Soc., 2011, 133, 19286; (b) P.
E. Car, M. Perfetti, M. Mannini, A. Favre, A. Caneschi and R.
Sessoli, Chem. Commun., 2011, 47, 3751; (c) M. Ren, D.
Pinkowicz, M. Yoon, K. Kim, L. M. Zheng, B. K. Breedlove and
M. Yamashita, Inorg. Chem., 2013, 52, 8342.
13 (a) F. Habib, J. Long, P. H. Lin, I. Korobkov, L. Ungur, W.
Wernsdorfer, L. F. Chibotaru and M. Murugesu, Chem. Sci.,
2012, 3, 2158; (b) M. Ren, S. S. Bao, N. Hoshino, T. Akutagawa,
B. Wang, Y. C. Ding, S. Wei and L. M. Zheng, Chem. Eur. J.,
2013, 19, 9619; (c) M. Guo, Y. Wang, J. F. Wu, L. Zhao and J. K.
Tang, Dalton Trans., 2017, 46, 564.
Conflicts of interest
There are no conflicts to declare.
14 (a) E. M. Pineda, N. F. Chilton, R. Marx, M. Dörfel, D. O. Sells,
P. Neugebauer, S. D. Jiang, D. Collison, J. van Slageren, E. J. L.
McInnes and R. E. P. Winpenny, Nat. Commun., 2014, 5, 5243;
(b) M. J. Giansiracusa, E. Moreno-Pineda, R. Hussain, R. Marx,
M. M. Prada, P. Neugebauer, S. Al-Badran, D. Collison, F. Tuna,
J. van Slageren, S. Carretta, T. Guidi, E. J. L. McInnes, R. E. P.
Winpenny and N. F. Chilton, J. Am. Chem. Soc., 2018, 140,
2504.
15 Q. Chen, J. Li, Y. S. Meng, H. L. Sun, Y. Q. Zhang, J. L. Sun and
S. Gao, Inorg. Chem., 2016, 55, 7980.
16 Y. Fang, X. Q. Ji, J. Xiong, G. Z. Li, F. Ma, H. L. Sun, Y. Q. Zhang
and S. Gao, Dalton Trans., 2018, 47, 11636.
17 H. Q. Tian, B. L. Wang, J. Lu, H. T. Liu, J. H. Su, D. C. Lia and J.
M. Dou, Chem. Commun., 2018, 54, 12105.
18 J. Long, F. Habib, P. H. Lin, I. Korobkov, G. Enright, L. Ungur,
W. Wernsdorfer, L. F. Chibotaru and M. Murugesu, J. Am.
Chem. Soc., 2011, 133, 5319.
19 F. Habib, G. Brunet, V. Vieru, I. Korobkov, L. F. Chibotaru and
M. Murugesu, J. Am. Chem. Soc., 2013, 135, 13242.
20 S. Y. Lin, W. Wernsdorfer, L. Ungur, A. K. Powell, Y. N. Guo, J.
K. Tang, L. Zhao, L. F. Chibotaru and H. J. Zhang, Angew. Chem.
Int. Ed., 2012, 51, 12767.
Acknowledgements
This work was financially supported by the National Natural
Science Foundation of China (Nos. 21961008, 21771043 and
21973046) and the Guangxi Natural Science Foundation (No.
2018GXNSFAA138123).
Notes and references
1
2
3
(a) Y. S. Meng, S. D. Jiang, B. W. Wang and S. Gao, Acc. Chem.
Res., 2016, 49, 2381; (b) D. N. Woodruff, R. E. P. Winpenny
and R. A. Layfield, Chem. Rev., 2013, 113, 5110.
(a) Z. Zhu, M. Guo, X. L. Li and J. K. Tang, Coord. Chem. Rev.,
2019, 378, 350; (b) J. L. Liu, Y. C. Chen and M. L. Tong, Chem.
Soc. Rev., 2018, 47, 2431.
(a) C. A. P. Goodwin, F. Ortu, D. Reta, N. F. Chilton and D. P.
Mills, Nature, 2017, 548, 439; (b) F. S. Guo, B. M. Day, Y. C.
Chen and M. L. Tong, A. Mansikkam-ki and R. A. Layfield,
Angew. Chem. Int. Ed., 2017, 56, 11445; (c) F. S. Guo, B. M.
Day, Y. C. Chen and M. L. Tong, A. Mansikkamäki and R. A.
Layfield, Science, 2018, 362, 1400.
4
5
P. Zhang, Y.-N. Guo and J. K. Tang, Coord. Chem. Rev., 2013,
57, 1728.
J. D. Rinehart, M. Fang, W. J. Evans and J. R. Long, Nat. Chem.,
2011, 3, 538.
21 A. Chakraborty, P. Bag, J. Goura, A. K. Bar, J. Sutter and V.
Chandrasekhar, Cryst. Growth Des., 2015, 15, 848.
10 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 11 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
22 (a) S. Yu, Z. B. Hu, Z. L. Chen, B. Li, Y. Q. Zhang, Y. N. Liang, D.
C. Liu, D. Yao and F. P. Liang, Inorg. Chem., 2019, 58, 1191; (b)
K. Wang, Z. L. Chen, H. H. Zou, S. H. Zhang, Y. Li, X. Q. Zhang,
W. Y. Sun and F. P. Liang, Dalton Trans., 2018, 47, 2337; (c) K.
Wang, Z. L.Chen, H. H. Zou, K. Hu, H. Y. Li, Z. Zhang, W. Y. Sun
and F. P. Liang, Chem. Commun., 2016, 52, 8297.
Bourhis, O.V. Dolomanov, R. J. Gildea, J. A. K. HVoiewwaArrdticlaenOdnliHne.
DOI: 10.1039/C9DT04434E
Puschmann, Acta Crystallogr., 2015, A71, 59.
23 (a) D. Casanova, M. Llunell, P. Alemany and S. Alvarez, Chem.
Eur. J., 2005, 11, 1479; (b) M. Llunell, D. Casanova, J. Cirera, P.
Alemany and S. Alvarez, SHAPE 2.1; University of Barcelona,
Barcelona, Spain, 2013.
24 (a) Y. Zhang, B. Ali, J. F. Wu, M. Guo, Y. Yu, Z. L. Liu and J. K.
Tang, Inorg. Chem., 2019, 58, 3167; (b) H. M. Dong, H. Y. Li, Y.
Q. Zhang, E. C. Yang and X. J. Zhao, Inorg. Chem., 2017, 56,
5611.
25 E. C. Mazarakioti, J. Regier, L. Cunha-Silva, W. Wernsdorfer,
M. Pilkington, J. K. Tang and T. C. Stamatatos, Inorg. Chem.,
2017, 56, 3568.
26 K. Zhang, G. P. Li, V. Montigaud, O. Cador, B. L. Guennic, J. K.
Tang and Y. Y. Wang, Dalton Trans., 2019, 48, 2135.
27 (a) Y. Xu, Y. S. Yu, X. D. Huang, S. S. Bao, H. M. Ding, Y. Q. Ma
and L. M. Zheng, Inorg. Chem., 2018, 57, 12143. (b) J. P. Lu, Y.
Q. Zhang, X. L. Li, M. Guo, J. F. Wu, L. Zhao and J. K. Tang, Inorg.
Chem., 2019, 58, 5715.
28 Y. N. Guo, G. F. Xu, Y. Guo and J. K. Tang, Dalton Trans., 2011,
40, 9953.
29 F. Aquilante, J. Autschbach, R. K. Carlson, L. F. Chibotaru, M.
G. Delcey, L. De Vico, I. Fdez. Galván, N. Ferré, L. M. Frutos, L.
Gagliardi, M. Garavelli, A. Giussani, C. E. Hoyer, G. Li Manni, H.
Lischka, D. Ma, P. Å. Malmqvist, T. Müller, A. Nenov, M.
Olivucci, T. B. Pedersen, D. Peng, F. Plasser, B. Pritchard, M.
Reiher, I. Rivalta, I. Schapiro, J. Segarra-Martí, M. Stenrup, D.
G. Truhlar, L. Ungur, A. Valentini, S. Vancoillie, V. Veryazov, V.
P. Vysotskiy, O. Weingart, F. Zapata and R. Lindh, J. Comput.
Chem., 2016, 37, 506.
30 (a) L. F. Chibotaru, L. Ungur and A. Soncini, Angew. Chem. Int.
Ed., 2008, 47, 4126; (b) L. Ungur, W. Van den Heuvel and L. F.
Chibotaru, New J. Chem., 2009, 33, 1224; (c) L. F. Chibotaru, L.
Ungur, C. Aronica, H. Elmoll, G. Pilet and D. Luneau, J. Am.
Chem. Soc., 2008, 130, 12445.
31 M. E. Lines, J. Chem. Phys., 1971, 55, 2977.
32 L. Zhang, J. L. Jung, P. Zhang, M. Guo, L. Zhao, J. K. Tang and B.
Le Guennic, Chem. Eur. J., 2016, 22, 1392.
33 L. T. A. Ho and L. F. Chibotaru, Phys. Rev. B., 2018, 98, 174418.
34 G. Huang, G. Fernandez-Garcia, I. Badiane, M. Camarra, S.
Freslon, O. Guillou, C. Daiguebonne, F. Totti, O. Cador, T.
Guizouarn, B. Le Guennic and K. Bernot, Chem. Eur. J., 2018,
24, 6983.
35 K. Zhang, D. Liu, V. Vieru, L. Hou, B. Cui, F. S. Guo, L. F.
Chibotaru and Y. Y. Wang, Dalton Trans., 2017, 46, 638.
36 (a) G. M. Sheldrick, SHELX–2014: Programs for Crystal
Structure Analysis, University of Göttingen, Göttingen, 2014;
(b) G. M. Sheldrick, Acta Crystallogr., 2015, C71, 3; (c) O. V.
Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard and H.
Puschmann, J. Appl. Crystallogr., 2009, 42, 339; (d) L. J.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 11
Please do not adjust margins

Dalton Transactions
Page 12 of 12
View Article Online
DOI: 10.1039/C9DT04434E
DyIII single-molecule magnets from ligands incorporating both amine and
acylhydrazine Schiff base groups: the centrosymmetric {Dy2} displaying dual
magnetic relaxation behaviors
Sen-Da Su,a Jia-Xin Li,b Fan Xu,a Chen-Xiao Wang,a Kai Wang,a Yan Li,a Shu-Hua Zhang,a Xiu-
Qing Zhang,a Yi-Quan Zhangb and Fu-Pei Lianga
Using novel ligands incorporating both amine and acylhydrazine Schiff base groups, two {Dy2} and a
{Dy6} SMMs has been synthesized. Two {Dy2} show dual magnetic relaxation behaviors, which could
be ascribed to the joint contributions of the single ion anisotropy and magnetic interactions.
1.2
0.9
N
NH
N
0.6
0.3
0.0
O
'
'
N

N
{Dy2}
{Dy6}
2.0 K
8
12.0 K
10
2
4
6
Amine
Schiff base
Acylhydrazine
Schiff base
' / cm3mol-1
5
4
3
2
1
0
3.0 K
10.0 K
N
NH
N
O
'
'

OH
HO
4
8
12
16
' / cm3mol-1
aGuangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and
Bioengineering, Guilin University of Technology, Guilin, 541004, China.
E-mail: fliangoffice@yahoo.com; kaiwang2011@yahoo.com
bJiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University,
Nanjing 210023, China.
E-mail: zhangyiquan@njnu.edu.cn