Trinuclear Lanthanide Coordination Clusters: Single-Molecule-Magnet Behavior and Catalytic Activity in the Friedel-Crafts Alkylation Reaction

Article abstract of DOI:10.1002/cplu.201900282

A new multidentate ligand (H₃L) was synthesized by the condensation reaction of 4-tert-butyl-2,6-diformylphenol and 2-amino-4-nitrophenol. The reaction of the ligand with hydrated lanthanide nitrate produced two isostructural trinuclear coordin

Full text of DOI:10.1002/cplu.201900282

Accepted Article
Title: Trinuclear Lanthanide Coordination Clusters: Single-Molecule-
Magnetic Behavior and Catalytic Activity in the Friedel--Crafts
Alkylation Reaction
Authors: Hari Pada Nayek, Carlos J Gomez Garcia, Arijit Sarkar, and
Samia Benmansour
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: ChemPlusChem 10.1002/cplu.201900282
Link to VoR: http://dx.doi.org/10.1002/cplu.201900282
A Journal of
www.chempluschem.org

ChemPlusChem
10.1002/cplu.201900282
FULL PAPER
Trinuclear Lanthanide Coordination Clusters: Single-Molecule-
Magnetic Behavior and Catalytic Activity in the Friedel--Crafts
Alkylation Reaction
[a]
[b]
[b]
[a]
Arijit Sarkar, Carlos J. Gómez-García, Samia Benmansour and Hari Pada Nayek*
Abstract: A new multi-dentate ligand (H
3
L) was synthesized by the
large paramagnetic anisotropy value in ionic form, lanthanides
have been extensively studied for the synthesis of new magnetic
materials. As a consequence of it, a huge number of magnetic
coordination clusters have been prepared and studied. Thus,
lanthanide complexes of Dy(III), Gd(III), Er(III), Ho(III), Tb(III)
have been intensively investigated.[19-23] Additionally, lanthanide
ions are also good Lewis acids, accordingly, many approaches
have been made with lanthanide ions to catalyze important
organic reactions. Wang and his co-workers performed a Lewis
acid catalyzed reaction between aldehydes and indole using
condensation reaction of 4-tert-butyl-2,6-diformylphenol and 2-
amino-4-nitrophenol. The reaction of the ligand with hydrated
lanthanide nitrate yielded of two isostructural trinuclear coordination
clusters:
Nd (DMF)
[Dy
3
L
3
(DMF)
3
(H
2
O)
2
]·3.8DMF
(1)
and
[
3
L
3
3
(H
2
O) ]·3.8DMF (2) (DMF = N, N-dimethylformamide).
2
Single Crystal X-ray diffraction analysis revealed that there are three
lanthanide ions arranged in an almost perfect linear way in both
complexes. Magnetic studies show an SMM behavior in the Dy
-
6
-
derivative with 
.
0
= 1.7x10 s and a thermal energy barrier of 7.0 cm
1
[24]
Both complexes were used as catalysts towards Friedel-Crafts
lanthanide triflate as a catalyst. Batey and his group reported
alkylation reaction of indole with different aldehydes with yield
varying from 59% – 98%. Complex 1 showed better catalytic
efficiency than complex 2. This report presents the first ever
approach of using trinuclear lanthanide coordination clusters as
catalysts for Friedel-Crafts Alkylation reaction.
3
a domino cyclisation reaction using Dy(OTf) as an efficient
catalyst.[25] These were essentially significant approaches with
the metal salt producing moderate to good yields of the products.
Recently, Kostakis and his group introduced heteronuclear
coordination clusters (3d/4f metals) as potential catalysts for
important organic transformations such as Friedel Crafts
alkylation,[
26]
Domino reaction,[27] Michael Addition,
[28]
Petasis
and Suzuki
Borono-Mannich multicomponent Reaction[
coupling reaction. Although homonuclear coordination clusters
29]
Introduction
[30]
of 3d metal ions have been proven to be an effective catalyst in
many organic reactions,[31, 32] lanthanide coordination clusters
have not been explored yet. Among the above mentioned
organic reactions, Friedel-Crafts alkylation leading to
bis(indolyl)alkanes can be considered as an important reaction
because these organic compounds can be are found in many
Polynuclear coordination clusters[1, 2] have acquired appreciable
interest over the past few decades due to their applicability in
magnetism[3-6], luminescence[7, 8], biology[9] and catalysis[10-15]
.
Self-assembly of smaller metal-organic fragments leading to
polynuclear coordination cluster is a challenging approach to
obtain such polynuclear coordination clusters. These
multimetallic clusters are generally encapsulated by one or more
organic ligands. Therefore, the correct selection of the
encapsulating ligands plays a decisive role in the design of such
polynuclear clusters. Polydentate ligands having multiple N and
O donor sites are preferred due to their ability to capture 3d, 4f
or 3d/4f ions simultaneously.[16-18] The structure of these clusters
are also dependent on the starting materials used and the
reaction conditions, metal ion/ligand ratio, pH, solvent,
temperature, reaction times, etc. In this context, the design and
synthesis of lanthanide coordination clusters represent an
biologically active natural products and they are also an useful
moiety in designing of drugs.[33-37] Usually, bis(indolyl)methanes
are synthesized by an electrophilic substitution reaction involving
an indole and carbonyl compounds (aldehydes and ketones) in
[38-41]
the presence of a Lewis acid catalyst and protic acid.
Friedel-Crafts alkylation reaction provides an excellent route for
such transformation. With this in mind, a new polydentate ligand,
H
3
L (scheme 1) which can accommodate multiple lanthanide
ions simultaneously have been designed and prepared.
additional challenge, since lanthanide possesses
a high
coordination number and show several different coordination
geometries for each coordination number. However, due to their
[
[
a]
b]
M.Sc. A. Sarkar, Dr. H. P. Nayek
Department of Applied Chemistry
Indian Institute of Technology (Indian School of Mines)
Dhanbad-826004, Jharkhand, India
E-mail: hpnayek@iitism.ac.in
Prof. C. J. Gómez-García, Dr. Samia Benmansour
Departamento de Química Inorgánica. Instituto de
Ciencia Molecular (ICMol)
3
Scheme 1. Structure of H L.
Universidad de Valencia, C/ Catedrático José Beltrán, 2. 46980
Paterna, Valencia, Spain
This ligand was reacted with hydrated lanthanide nitrates to yield
two trinuclear isostructural coordination complexes,
Ln (DMF) (H O) ]·3.8DMF with Ln = Dy(III) (1) and Nd(III) (2).
Besides the synthesis of the ligand, we report the structure and
[
3
L
3
3
2
2
Supporting information for this article is given via a link at the end of the
document.
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.201900282
FULL PAPER
magnetic characterization of both complexes as well as their
catalytic activities in Friedel-Crafts alkylation reaction of indole
with various aldehydes.
(DMSO). The ligand was characterized by FT-IR, NMR
spectroscopy and mass spectrometry. The ligand was employed
to synthesize two iso-structural trinuclear coordination clusters
formulated as [Ln
and Nd(III) (2) (L = deprotonated and trianionic form of the
ligand) by reacting it with Ln(NO ∙6H O (Ln = Dy and Nd) using
triethylamine as a base in DMF as solvent (scheme 3). Both
complexes are found to be air stable and partially soluble in
3 3 3 2 2
L (DMF) (H O) ]·3.8DMF with Ln = Dy(III) (1)
Results and Discussion
3
)
3
2
Synthetic procedures
2 2 3
MeOH, EtOH, CH Cl , CHCl and fully soluble in DMF, DMSO.
3
The polydentate Schiff base ligand (H L) was prepared by the
The formulation of complexes 1 and 2 was confirmed by
different characterization techniques such as FT-IR
spectroscopy, elemental analysis and single crystal X-ray
diffraction analysis.
condensation reaction of 4-tert-butyl-2,6-diformylphenol and 2-
amino-4-nitrophenol in a 2:1 (v/v) mixture of ethanol and toluene
under reflux (scheme 2). The brown coloured ligand was
separated from the reaction mixture and dried. It was not soluble
in ethanol, methanol, CH
2 2 3
Cl , CHCl , partially soluble in
dimethylformamide (DMF) and fully soluble in dimethylsulfoxide
3
Scheme 2. Synthesis of the Schiff base ligand H L.
Scheme 3. Syntheses of the coordination clusters of Dy (1) and Nd (2).
-
1
FT-IR and NMR spectroscopy
The FT-IR spectrum of the free ligand (H
absorption band at 3445 cm- assigned to the [ν(O–H)]
[ν(C=N)] stretching band appears at 1640 cm . In complexes 1
and 2, the [ν(C=N)] stretching vibrations are shifted to lower
3
L) shows a broad
1
-1
-1
energies and appear at 1623 cm and 1621 cm , respectively.
The existence of a band at around 1660 cm-1 which accounts for
stretching (figure S1, supporting information). The azomethine
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.201900282
FULL PAPER
the [ν(C=O)] stretching, confirms the presence of DMF
molecules in the structure of complexes 1 and 2.[42, 43] This
observation is further supported by single crystal X-ray
diffraction analyses (vide infra). As mentioned earlier, the ligand
was not soluble in common organic solvents and, therefore, the
crystallize in the triclinic space group P-1. The crystallographic
data of the complexes are listed in Table S1. The coordination
cluster in complexes 1-2 is very similar. Therefore, only the
structure of 1 is discussed in detail. The molecular structure of 1
and 2 are shown in figure 1a and figure S5 (supporting
information). The trinuclear homometallic complexes are formed
1H spectrum was recorded in DMSO-d
. It resulted in a complex
6
spectrum (figure S2-3, supporting information) with more
resonance signals than expected, indicating the presence of
by three deprotonated ligands [L
3
]3- connected to three Dy(III)
ions (figure 1a). Each ligand uses three phenolate oxygen atoms
and two imine nitrogen atoms to coordinate the Dy(III) ions. The
coordination environment around each Dy(III) and Nd(III) ions is
distinct as shown in figure 1b and figure S6 in the supporting
information. In fact, Dy1 is octa-coordinated and shows a
triangular dodecahedron geometry while Dy2 and Dy3 are nona-
coordinated and show tricapped trigonal prism and capped
square antiprism geometries, respectively (Figure 1b), as
calculated by the continuous symmetry and shape analysis (see
supporting information).
both, keto-amine and enol-imine forms of H
similar observation was earlier documented for the related ligand
,6-bis{N-(2-hydroxyphenyl)iminomethyl}-4-methylphenol.[44]
3
L in solution. A
2
Moreover, the ESI-MS spectrum shows the base peak with m/z
of 501.17 assigned to [L+Na]+ fragment (figure S4, supporting
information).
Crystallography
Complexes 1-2 are isostructural and have the general formula
[
3 3 3 2 2
Ln L (DMF) (H O) ]·3.8DMF, where Ln = Dy(1) and Nd(2). They
(
a)
(
b)
Figure 1. (a) Molecular structure of 1. (b) Coordination environment of the Dy(III) ions in 1. Hydrogen atoms and DMF molecules are omitted for clarity. Colour
code: Grey = C, red = O, blue = N and green = Dy.
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.201900282
FULL PAPER
Dy1 is bounded by four phenolate oxygen atoms (O2, O1, O8,
and O17), one imine nitrogen (N1) and three oxygen atoms of a
coordinated water (O22) and two coordinated DMF molecules
3
2
2
0
5
0
6
5
4
3
6
K
1.8 K
(
O23 and O28). The central Dy(III) ion (Dy2) is coordinated by
three imine nitrogen atoms (N2, N5 and N10) and six bridging
phenolate oxygen atoms (O2, O3, O8, O9, O16 and O17). The
Dy3 is surrounded by five phenolate oxygen atoms (O3, O9,
O10, O15 and O16), two imine nitrogen atoms (N6, N9) and two
oxygen atoms from a water (O25) and a DMF (O24) molecules.
The three Dy(III) centres are arranged in an almost linear
fashion with a Dy1-Dy2-Dy3 angle of 167.7°. The Dy-Dy
distances are Dy1-Dy2 = 3.5371(1) and Dy2-Dy3 = 3.5503 (1) Å.
12 K
100
10
1
10
2
10
3
15
10
5
1
2 K
00
0
1
101
102
103
Magnetic properties
The product of the magnetic susceptibility times the temperature
n
(Hz)
m
( T) at room temperature per formula (i.e., per three Ln(III)
6
5
4
3
2
1
0
0.6
.5
6.5 K
3
-1
ions) is ca. 43.0 and 5.0 cm K mol for 1 and 2, respectively,
0
very close to the expected values for three isolated Ln(III) ions
0.4
0.3
3
-1
3
-1
(
=
42.5 cm K mol with g
J
= 4/3 for 1 and 4.9 cm K mol with g
T shows a
J
0
0
.2
.1
8/11 for 2). When the samples are cooled, 
m
1.8 K
12 K
continuous decrease in the two compounds, reaching values of
ca. 29.5 and 1.8 cm3 K mol-1 at 2 K for 1 and 2, respectively
0.0
1
01
102
103
(
figure S7, supporting information). The decrease witnessed in
the both complexes may be assigned to weak
a
antiferromagnetic Ln-Ln coupling through the triple phenoxido
bridge and/or to the progressive depopulation of the higher
energy Stark levels resulted from the splitting of the 6H15/2 and
4
[45]
12 K
I
9/2 ground levels due to the ligand field.
In order to determine the possible presence of a SMM behaviour
we have performed AC susceptibility measurements at very low
temperatures for both compounds. Compound 2 does not show
any AC signal even when a DC field is applied (figure S8-S9,
supporting information). In contrast, compound 1 shows a
1
00
101
n
102
103
(Hz)
Figure 2. Frequency dependence of the in phase, (’
” , down) susceptibility for compound 1. Solid lines are the best fit to the
Debye model (see text). Insets show the high temperature measurements.
m
, up) and out of phase
(
m
frequency-dependent in phase (’
m
) and out of phase AC signal
m
) at very low temperatures without any applied DC field
(
(
(
”
Figure 2). The fit of these AC signals to the Debye model
equations 1 and 2, solid lines in Figure 2)46,47 gives  values in
m
The relaxation times () obtained with the fit of ” to the Debye
model follow an Arrhenius law in the measured temperature
range (1.8-12.0 K) as can be seen in Figure 4. Thus, the plot of
the range 0.68-0.75, suggesting multiple relaxation processes
that might be due to the presence of up to three
crystallographically independent Dy(III) centres in the cluster
with three different environments (see above). The Cole-Cole or
Ln () vs. 1/T gives a straight line in the 1-8-12.0 K range with
-1

0
= 1.7x10-6 s and a thermal energy barrier of 7.0 cm . These
Argand plot (”
Figure 3) that can also be fit with the Debye model (solid lines
in Figure 3) with  values in the same 0.68-0.75 range,
confirming the results obtained with the frequency-dependent ’
m
m
vs.  ’) gives symmetrical semi-elliptical curves
data indicate that below 12.0 K the slow relaxation of the
magnetization is only due to the thermal barrier (Orbach
relaxation mechanism).[48]
(
m
m
and ” signals (Figure 2).
Friedel crafts alkylation reaction
Both complexes (1 and 2) were employed to study their catalytic
efficiency for Friedel crafts alkylation reaction involving indole
and different aldehydes. It has been already established that
mononuclear Dy(III) compounds act as an efficient catalyst for
ꢄꢅ훼
1
푠푒푛 ⁄ ꢆ휋]
(
ꢀ −ꢀ )[1ꢂ(ꢃ휏)
′
푇
ꢁ
2
휒 (휔) = 휒 +
(1)
ꢇ(ꢄꢅ훼)
푆
ꢂ2(ꢃ휏)ꢄꢅ훼푠푒푛 ⁄ ꢆ휋ꢂ(ꢃ휏)
1
1
2
ꢄꢅ훼
1
푐표푠 ⁄ ꢆ휋
2
(
ꢀ −ꢀ )(ꢃ휏)
′
푇
ꢁ
11
휒 ꢈ(휔) = 휒 +
such reaction. Therefore, we have initially chosen complex 1 to
푆
ꢂ2(ꢃ휏)ꢄꢅ훼푠푒푛 ⁄ ꢆ휋ꢂ(ꢃ휏)
1
ꢇ(ꢄꢅ훼)
1
2
study its catalytic activity for such a reaction. The optimization of
the reaction was done with benzaldehyde and indole (scheme 4).
At first, the reaction was carried out without any catalyst at room
temperature and no product was detected (Table 1, entries 1-2).
When the temperature was raised to 60 °C the product was
formed with a yield of 44 % (6 h, Table 1, entry 3) and 37 % (12
(
2)
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.201900282
FULL PAPER
h, Table 1, entry 4). Then, we employed complex 1 and
gradually optimized the reaction condition.
4
1.8 K
3
2
1
0
Scheme 4. Friedel crafts alkylation reaction of indole and benzaldehyde
catalyzed by 1.
0
0
0
0
0
0
0
0
.7
The catalyst was not fairly soluble in solvents such as CHCl
3
,
6.0 K
.6
CH Cl , CH CN. Accordingly, the yield of the reaction in those
2
2
3
.5
.4
solvents was very low (10 %, 11 % and 27 %, respectively).
However, the solubility of catalyst 1 could be improved in alcohol.
We screened the reaction in MeOH, EtOH and H O and
2
obtained 87 %, 96 % and 81 % yields, respectively. In order to
make the catalytic process a mild one and avoid any toxicity due
to the solvents, a mixture of water (2 mL) and ethanol (4 mL)
was employed as a reaction medium for the reaction. Then, the
reaction was carried with a varying amount of the catalyst (0.5-
.3
.2
.1 12 K
.0
1
2 K
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
5
10
15
20
25
30
3
-1
c
' (cm mol )
m
Figure 3. Cole-Cole or Argand plot for compound 1 in the 1.8-12.0 K range.
Solid lines are the best fit to the Debye model (see text). Inset shows the high
temperature measurements.
1.25 % mol) with different reaction times (in the range 2-6 hours).
We found that the highest yield (98 %) was obtained with the
optimized reaction conditions shown in Table 1, entry 12.
Therefore, all the reactions were performed under this reaction
condition. Complex 2 was also tested as a catalyst under the
same conditions and resulted in a 65 % conversion. The
decrease in conversion may be correlated with the presence of
less Lewis acidic Nd3+ in complex 2 (compared to Dy3+ in
complex 1). The mononuclear lanthanide salts provided low
yields, 60 % and 48 % for Dy(III) and Nd(III) salts, respectively
-
-
-
7
8
9
-
-
-
-
10
11
12
13
(
Table 1, entries 6-7). This observation implies presence of
cooperative effect among lanthanide ions in both complexes.
Ten different aldehydes were screened using complex 1 since
this complex is the most efficient catalyst among both
complexes (Table S4, supporting information). Benzaldehyde
and 1-naphthaldehyde gave excellent results with yields of 98 %
and 92 % respectively (Scheme 5).
0
.0 0.1 0.2 0.3 0.4 0.5 0.6
-
1
1
/T (K )
Figure 4. Arrhenius plot of the relaxation times in the 1.8-3.0 K range. The
solid line is the best fit to the Arrhenius law (see text).
Table 1. Friedel crafts alkylation reaction of indole and benzaldehyde catalyzed by 1.
Entry
Catalyst
Solvent System
EtOH/H
Catalyst loading
Temp (°C)
Time (h)
Yield (%)
1
2
3
4
5
6
7
8
9
-
-
-
-
2
O
-
-
-
-
rt
rt
6
12
6
12
6
6
6
6
6
6
6
6
6
6
6
4
2
-
-
EtOH/ H
EtOH/ H
EtOH/ H
2
O
O
O
2
2
60
60
60
60
60
60
60
60
60
60
60
50
80
60
60
60
44
37
41
60
48
96
81
72
74
98
79
81
68
65
-
H
3
L
EtOH/H
EtOH/H
EtOH/H
2
O
O
O
1.0
1.0
1.0
1.0
1.0
0.5
0.75
1.0
1.25
1.0
1.0
1.0
1.0
1.0
Dy(NO
Nd(NO
3
)
3
·6H
·6H
2
O
O
2
2
3
)
3
2
1
1
1
1
1
1
1
1
1
1
2
EtOH
H
2
O
10
11
12
13
14
15
16
17
18
EtOH/H
EtOH/H
EtOH/H
EtOH/H
EtOH/H
EtOH/H
EtOH/H
EtOH/H
EtOH/H
2
O
2
O
2
O
2
O
2
O
2
O
2
O
2
O
2
O
6
65
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.201900282
FULL PAPER
Scheme 5. Friedel crafts alkylation reaction of indole with different aldehydes catalysed by 1. Reaction conditions: indole 0.50 mmol, aldehyde 0.25 mmol, solvent
EtOH/H O (2:1) 6 mL, catalyst 1 mol %, temperature 60 °C, 6 hours.
2
The stability of catalyst 1 was checked by powder X-ray Conclusions
diffraction (PXRD). For this, the catalyst was heated at 60 °C in
a mixture of water and ethanol for 6 hours (the optimized
reaction condition). Then, it was filtered, dried and characterized
by CHN analysis, TGA (see supporting information) and powder
X-ray diffraction (figure 5). No structural change was detected,
suggesting that the coordination cluster remains intact in
solution and is the active species in the catalytic Friedel crafts
alkylation reaction. However, the reusability test of the catalyst
was not performed as it was difficult to recover the catalyst from
the homogeneous reaction mixture.
We have successfully synthesized two new coordination clusters
containing three lanthanide ions (Dy3+ and Nd ) bridged by
phenoxido oxygen atoms nearly in a linear fashion. Complex 1
showed SMM behaviour and excellent catalytic activities for
Friedel crafts alkylation of indole with different aldehydes with
yields from 55 to 98 %. These results open the possibility of
using coordination cluster of lanthanides as catalyst for this
Friedel crafts alkylation reaction. We are now investigating the
details of the mechanism.
3+
Experimental Section
Materials
All syntheses were performed under aerobic condition. All reagents and
solvents used for synthesis were of analytical grade and employed
without any further purification. Chemicals such as 4-tert-butylphenol, 2-
amino-4-nitrophenol, manganese dioxide and lanthanide nitrates were
purchased from Sigma Aldrich, India and Alfa Aesar, India respectively.
Solvents were purchased from Rankem, India. 4-tert-butyl-2,6-
diformylphenol was prepared following the previously reported
method.[49
Analytical techniques
]
1H NMR and C{ H} NMR spectra were recorded on a BRUKER
AVANCE II-400 spectrometer. FT-IR spectra were recorded on a Perkin-
Elmer Spectrum GX spectrometer in the range 4000-400 cm-1 with
samples prepared as KBr discs. Elemental analyses were performed in
13
1
Figure 5. Powder XRD patterns of 1 before and after treating it with the
optimized reaction condition.
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.201900282
FULL PAPER
Vario Micro cube for C, H, N, S Analyser by Elemental Analyser System
Thermo Finnigan FLASH EA 1112 series. Single crystal X-ray diffraction
data were collected on an Agilent Supernova X-calibur diffractometer
equiped with Eos CCD detector. The CCDC 1891530 (1) and 1891531
Acknowledgements
The wrok is financillay supported by the Science and
Engineering Research Board (SERB), India (Order No.
EEQ/2018/000014) and the Spanish MINECO (project
CTQ2017-87201-P AEI/FEDER, UE) and the Generalitat
Valenciana (Prometeo program).
(
2) contain the supplementary crystallographic data for this paper. These
data can be obtained free of charge from The Cambridge
Crystallographic Data Centre.
Magnetic properties
Magnetic susceptibility measurements were carried out in the
temperature range 2–300 K with an applied magnetic field of 0.5 T on
polycrystalline samples of compounds 1 and 2 (with masses of 7.32 and
Keywords: coordination chemistry • Friedel--Crafts
alkylation • heterogeneous catalysis • lanthanides • single-
molecule magnetism
8.24 mg, respectively) with a Quantum Design MPMS-XL-5 SQUID
susceptometer. AC susceptibility measurements were performed on the
same samples with fields oscillating at frequencies in the range 0.2-1500
Hz in the temperature range 1.8-12.0 K. For both samples, we initially
performed AC measurements at 1.8 K as a function of the applied DC
field (up to 0.5 T) with an AC frequency of 110 Hz (see supporting
information). Susceptibility data were corrected for the contribution of the
sample holder and the diamagnetic contribution of the salts using
Pascal’s constants.[50]
[
[
[
[
1]
2]
3]
4]
G. E. Kostakis, A. K. Powell, Coord. Chem. Rev. 2009, 253, 2686-
697.
2
X.-Y. Zheng, J. Xie, X.-J. Kong, L.-S. Long, L.-S. Zheng, Coord.
Chem. Rev. 2019, 378, 222-236.
M. Yadav, A. Mondal, V. Mereacre, S. K. Jana, A. K. Powell, P.
W. Roesky, Inorg. Chem. 2015, 54, 7846-7856.
J. Goura, J. P. S. Walsh, F. Tuna, V. Chandrasekhar, Dalton
Trans. 2015, 44, 1142-1149.
Synthesis of the ligand (H
The ligand was synthesized by the condensation of 4-tert-butyl-2,6-
diformylphenol (0.5 g, 2.43 mmol) with 2-amino-4-nitrophenol (0.749 g,
3
L)
[5]
[6]
J. Goura, J. P. S. Walsh, F. Tuna, V. Chandrasekhar, Inorg.
Chem. 2014, 53, 3385-3391.
R. Sessoli, A. K. Powell, Coord. Chem. Rev. 2009, 253, 2328-
2341.
4.86 mmol) under reflux in a mixture of ethanol (30 mL) and toluene (15
mL) for four hours. The resulting deep brown solid was isolated and
washed with ethanol several times to remove any unreacted starting
materials. It was dried under reduced pressure. Yield: 0.918 g, 79.0 %.
ESI-MS scan: expected 478.45; Observed 501.17 [M + Na] . IR (KBr, cm
1)
: 3445(br), 3080(w), 3041(w), 2963(m), 2871(w), 1640(m), 1617(s),
[7]
[8]
J.-C. G. Bunzli, S. V. Eliseeva, Chem. Sci. 2013, 4, 1939-1949.
J. Rocha, L. D. Carlos, F. A. A. Paz, D. Ananias, Chem. Soc. Rev.
2011, 40, 926-940.
+
-
[9]
H. Tsukube, S. Shinoda, Chem. Rev. 2002, 102, 2389-2404.
[10] M. Shibasaki, N. Yoshikawa, Chem. Rev. 2002, 102, 2187-2210.
[11] G. K. Veits, J. Read de Alaniz, Tetrahedron, 2012, 68, 2015-2026.
[12] G. Maayan, G. Christou, Inorg. Chem. 2011, 50, 7015-7021.
1
8
517(s), 1476(m), 1327(s), 1239(s), 1130(w), 1086(m), 1058(m), 1014(w),
89(w), 828(m), 752(m), 667(m), 579(m).
[
13] V. G. K., W. D. R., R. d. A. Javier, Angew. Chem., Int. Ed. 2010
49, 9484-9487.
,
General procedure for the synthesis of complexes 1 and 2:
Complexes 1 and 2 were synthesized following the same procedure. To
a solution of H L (0.125 mmol) and Et N (0.174 mL) in 6 mL of DMF,
3
3
[14] D. P. A., B. R. A., Angew. Chem., Int. Ed. 2013, 52, 10862-10866.
[15] L. I. Palmer, J. Read de Alaniz, Organic Letters, 2013, 15, 476-
479.
hydrated lanthanide nitrate (0.125 mmol) was added. The resulting
mixture was stirred for 24 hours at room temperature to obtain an orange
coloured solution. The resulting solution was filtered off and the filtrate
was kept for slow evaporation. Brown coloured crystals suitable for single
crystal X-ray diffraction analysis were obtained after 3 weeks.
[16] A. Dey, S. Das, S. Kundu, A. Mondal, M. Rouzières, C.
Mathonière, R. Clérac, R. Suriya Narayanan, V. Chandrasekhar,
Inorg. Chem. 2017, 56, 14612-14623.
[17] V. Chandrasekhar, P. Bag, W. Kroener, K. Gieb, P. Müller, Inorg.
Chem. 2013, 52, 13078-13086.
[
Dy
3
L
3
(DMF)
3
(H
2
O)
2
]·3.8DMF (1): Yield: 60 mg, 58% (with respect to
29.8: C 45.35 %, H 4.48 %, N
ligand). Anal Calcd. for C92.4
H
108.6Dy
3
N
18.8
O
[18] H. L. C. Feltham, R. Clérac, L. Ungur, L. F. Chibotaru, A. K.
Powell, S. Brooker, Inorg. Chem. 2013, 52, 3236-3240.
[19] K. C. Mondal, G. E. Kostakis, Y. Lan, W. Wernsdorfer, C. E.
Anson, A. K. Powell, Inorg. Chem. 2011, 50, 11604-11611.
[20] T. D. Pasatoiu, J.-P. Sutter, A. M. Madalan, F. Z. C. Fellah, C.
Duhayon, M. Andruh, Inorg. Chem. 2011, 50, 5890-5898.
[21] A. K. Jami, V. Baskar, E. C. Sañudo, Inorg. Chem. 2013, 52,
2432-2438.
-
1
1
3
1
0.76 %. Found: C 45.32%, H 4.56%, N 10.92%. (KBr pellet, cm ):
440(br), 2956(s), 1662(w), 1488(m), 1381(m), 1291(s), 1178(w),
059(m), 888(w), 836(m), 754(w), 646(m).
[
Nd
3
L
3
(DMF)
3
(H
2
O)
2
]·3.8DMF (2): Yield: 48 mg, 48% (with respect to
29.8: C 46.39 %, H 4.57 %, N
ligand). Anal Calcd. for C93.4
H
3 18.8
108.6Nd N O
-
1
1
3
1
1.00 %. Found: C 46.37 %, H 4.56 %, N 11.15 %. IR (KBr pellet, cm ):
442(br), 2969(s), 1658(m), 1620(w), 1576(w), 1479(m), 1397(w),
282(s), 1173(m), 1085(w), 1052(w), 835(w), 649(m).
[22] B. Na, X.-J. Zhang, W. Shi, Y.-Q. Zhang, B.-W. Wang, C. Gao, S.
Gao, P. Cheng, 2014, 20, 15975-15980.
Catalytic protocol: Aldehyde (0.25 mmol) and Indole (0.5 mmol) were
added to a mixture of EtOH/H O (2:1, 6 mL) followed by addition of the
catalyst (1 %, mol). The resulting solution was heated at 60 °C for 6
hours. Then, the reaction mixture was diluted with CH Cl and filtered
2
[23] L. Zhang, P. Zhang, L. Zhao, J. Wu, M. Guo, J. Tang, Dalton
Trans. 2016, 45, 10556-10562.
2
2
[24] D. Chen, L. Yu, P. G. Wang, Tetrahedron Lett. 1996, 37, 4467-
4470.
through celite. The filtrate was concentrated under low pressure and the
crude was extracted with a ethyl acetate/water mixture. The organic layer
was dried over anhydrous sodium sulphate. The resulted product was
purified by column chromatography (chloroform: petroleum ether, 50:50).
The isolated product was characterized by NMR spectroscopy and mass
spectrometry (figures S10-S39, supporting information).
[25] S.-W. Li, R. A. Batey, Chem. Commun. 2007, 3759-3761.
[26] K. Griffiths, P. Kumar, G. R. Akien, N. F. Chilton, A. Abdul-Sada,
G. J. Tizzard, S. J. Coles, G. E. Kostakis, Chem. Commun. 2016
,
52, 7866-7869.
[27] K. Griffiths, C. W. D. Gallop, A. Abdul-Sada, A. Vargas, O.
Navarro, G. E. Kostakis, Chem. - Eur. J. 2015, 21, 6358-6361.
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.201900282
FULL PAPER
[
28] K. Griffiths, A. C. Tsipis, P. Kumar, O. P. E. Townrow, A. Abdul-
Sada, G. R. Akien, A. Baldansuren, A. C. Spivey, G. E. Kostakis,
Inorg. Chem. 2017, 56, 9563-9573.
[40] S.-J. Ji, M.-F. Zhou, D.-G. Gu, Z.-Q. Jiang, T.-P. Loh, Eur. J.
Inorg. Chem, 2004, 2004, 1584-1587.
[41] N. D. Kokare, J. N. Sangshetti, D. B. Shinde, Chin. Chem. Lett.
2008, 19, 1186-1189.
[
[
[
[
[
[
[
[
[
29] P. Kumar, K. Griffiths, S. Lymperopoulou, G. E. Kostakis, RSC
Adv. 2016, 6, 79180-79184.
[42] R. Vinayak, A. Harinath, C. J. Gómez-García, T. K. Panda, S.
Benmansour, H. P. Nayek, ChemistrySelect, 2016, 1, 6532-6539.
[43] S. Saha, P. P. Jana, C. J. Gómez-García, K. Harms, H. P. Nayek,
Polyhedron, 2016, 104, 58-62.
30] P. Kumar, K. Griffiths, C. E. Anson, A. K. Powell, G. E. Kostakis,
Dalton Trans. 2018, 47, 17202-17205.
31] T. Iwasaki, Y. Maegawa, Y. Hayashi, T. Ohshima, K. Mashima, J.
Org. Chem. 2008, 73, 5147-5150.
[44] M. Hasegawa, Y. Yamada, K.-i. Kumagai, T. Hoshi, Zeitschrift für
Naturforschung B, 1999, 54, 929.
32] Y. Maegawa, T. Ohshima, Y. Hayashi, K. Agura, T. Iwasaki, K.
Mashima, ACS Catal. 2011, 1, 1178-1182.
[45] L. Sorace, D. Gatteschi, in Electronic Structure and Magnetic
Properties of Lanthanide Molecular Complexes. Eds.: R. A.
Layfield, M. Murugesu; 2015; Vol. 1, pp 1-25.
33] S. Safe, S. Papineni, S. Chintharlapalli, Cancer Lett. 2008, 269,
3
26-338.
34] C. Hong, G. L. Firestone, L. F. Bjeldanes, Biochem. Pharmacol.
002, 63, 1085-1097.
[46] S. M. J. Aubin, Z. Sun, L. Pardi, J. Krzystek, K. Folting, L. Brunel,
2
A. Rheingold, G. Christou, D. N. Hendrickson, Inorg. Chem. 1999
38, 5329.
,
35] M. Shiri, M. A. Zolfigol, H. G. Kruger, Z. Tanbakouchian, Chem.
Rev. 2010, 110, 2250-2293.
[47] M. Hagiwara, K. Nagata, J. Magn. Magn. Mater. 1998, 177–181,
91–92.
36] S. Imran, M. Taha, N. H. Ismail, S. Fayyaz, K. M. Khan, M. I.
Choudhary, Bioorg. Chem. 2016, 68, 90-104.
[48] R. Orbach, Proc. R. Soc. London, Ser. A 1961, 264, 458.
[49] Y. Fu, Z. Xing, C. Zhu, H. Yang, W. He, C. Zhu, Y. Cheng,
Tetrahedron Lett. 2012, 53, 804-807.
37] C. Grosso, A. L. Cardoso, A. Lemos, J. Varela, M. J. Rodrigues,
L. Custódio, L. Barreira, T. M. V. D. Pinho e Melo, Eur. J. Med.
Chem. 2015, 93, 9-15.
[50] G. A. Bain, J. F: Berry, J. Chem. Educ. 2008, 85, 532-536.
[
[
38] J. S. Yadav, B. V. Subba Reddy, C. V. S. R. Murthy, G. Mahesh
Kumar, C. Madan, Synthesis, 2001, 0783-0787.
39] M. L. Deb, P. J. Bhuyan, Tetrahedron Lett. 2006, 47, 1441-1443.
This article is protected by copyright. All rights reserved.

ChemPlusChem
10.1002/cplu.201900282
FULL PAPER
Entry for the Table of Contents
FULL PAPER
Arijit Sarkar Carlos J. Gómez-García,
Samia Benmansour and Hari Pada
Nayek,*
Page No. – Page No.
Title
Two new trinuclear lanthanide coordination clusters have been synthesized from a
tridentate Schiff base ligand (H L) in presence of triethyl amine. One of the clusters
3
clearly exhibits SMM behavior. However, both of them are successful in providing
good catalytic activity toward Friedel crafts alkylation reaction of indole with different
aldehydes. Dy cluster is certainly more efficient than its Nd analogue.
This article is protected by copyright. All rights reserved.