Syntheses and solid state structures of cyclam-based copper and zinc compounds Dedicated to Professor Maria José Calhorda on the occasion of her 65th birthday.

Article abstract of DOI:10.1016/j.jorganchem.2013.11.015

Copper(II) and zinc(II) complexes of general formula [{H ₂(4-BtuPhCH₂)₂Cyclam}Cu]SO₄, 1, [{H₂(PhCH₂)₂Cyclam}Cu]X, (X = SO₄, 2; X = (CH₃COO)₂, 3), [{H₂(PhCH ₂)₂Cyclam}Zn]SO₄, 5, and [{H ₂(PhCH₂)₂Cyclam)}ZnCl]Cl, 6, were prepared by reaction of H₂Bn₂Cyclam (Bn = PhCH₂ or 4-BtuPhCH₂) with one equiv. of the appropriate Cu(II) or Zn(II) salt. The preparation of Cu(II) complexes of general formula [{H ₂(MeOCH₂)₂Cyclam}Cu]X (X = SO₄, 7, (CH₃COO)₂, 8, and CuCl₄, 9) displaying a modified cyclam ligand with two N-CH₂OMe pending arms was achieved by nucleophilic attack of methanol to the bridging methylene groups of 1,4,8,11-tetraazatricyclo[9.3.1.1^4,8]hexadecane in a Cu²⁺ mediated process.

Full text of DOI:10.1016/j.jorganchem.2013.11.015

Journal of Organometallic Chemistry 760 (2014) 130e137
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Syntheses and solid state structures of cyclam-based copper and zinc
compounds
*
Luis G. Alves, Manuel Souto, Filipe Madeira, Pedro Adão, Rui F. Munhá, Ana M. Martins
Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
a r t i c l e i n f o
a b s t r a c t
t
Article history:
Copper(II) and zinc(II) complexes of general formula [{H2(4 ꢀ BuPhCH2)2Cyclam}Cu]SO4, 1,
[{H2(PhCH2)2Cyclam}Cu]X, (X SO4, 2; (CH3COO)2, 3), [{H2(PhCH2)2Cyclam}Zn]SO4, 5, and
Received 16 October 2013
Received in revised form
12 November 2013
¼
X
¼
[{H2(PhCH2)2Cyclam)}ZnCl]Cl, 6, were prepared by reaction of H2Bn2Cyclam (Bn
¼
PhCH2 or
t
4 ꢀ BuPhCH2) with one equiv. of the appropriate Cu(II) or Zn(II) salt.
Accepted 13 November 2013
The preparation of Cu(II) complexes of general formula [{H2(MeOCH2)2Cyclam}Cu]X (X ¼ SO4, 7,
(CH3COO)2, 8, and CuCl4, 9) displaying a modified cyclam ligand with two N-CH2OMe pending arms was
achieved by nucleophilic attack of methanol to the bridging methylene groups of 1,4,8,11-tetraazatricyclo
[9.3.1.14,8]hexadecane in a Cu2þ mediated process.
Dedicated to Professor Maria José Calhorda
on the occasion of her 65th birthday.
Ó 2013 Elsevier B.V. All rights reserved.
Keywords:
Cyclam
Zinc complexes
Copper complexes
Azamacrocycles
Hybrid polymers
1. Introduction
macrocycle backbone, making them the less sterically hindered and
simultaneously the most negative atoms [8]. The reactions of 3,14-
The field of macrocyclic complexes is extremely wide due to the
diverse uses found for that kind of compounds in catalysis [1], se-
lective metal recovery and recycling [2], sensors [3] and therapy
and diagnosis [4]. Among other macrocyclic ligands, cyclens and
cyclams were extensively studied because they are able to accom-
modate and stabilize a large variety of metal cations in several
oxidation states [5]. Copper(II) complexes based on such ligands
display high thermodynamic stability with respect to metal disso-
ciation as well as interesting electrochemical properties. The
properties of tetra-N-functionalized cyclams are quite different
from those of the unsubstituted parent macrocyclic compounds [6].
Moreover, coordinative pendant arms on the nitrogen atoms allow
the tuning of the properties and the selectivity for particular metal
ions [7]. The establishment of selective synthetic procedures for
tetrazamacrocyclic compounds is thus an important topic. Trans-
N,N0-disubstituted cyclams may be obtained by reactions of the
bisaminal cyclam 1,4,8,11-tetraazatricyclo[9.3.1.14,8]hexadecane
with electrophiles [8]. Those reactions are highly selective because
the stereochemical conformation imposed by the methylene cross-
bridges forces trans-nitrogen atoms lone pairs to point out of the
dimethyl-2,6,13,17-tetraazapentacyclo[16.4.12.17.16.13.0.07.12]tetra-
cosane
or
5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazatricyclo
[9.3.1.14.8]hexadecane with Cu(ClO4)2$6H2O in methanol were re-
ported to give metal complexes displaying trans-N,N0-CH2OMe
cyclam ligands [9].
In recent years we have been using dianionic trans-N,N0-disub-
stituted cyclams as supporting ligands for early metals, namely
block-s metals (Mg) [10], lanthanides (Ln) [11] and particularly,
early transition metals ((Zr, Hf)) [12]. The results obtained allowed
us establishing structure/reactivity relations that where explored in
catalytic applications such as polymerization [13] and hydro-
amination [14]. A new method for cyclams functionalization was
attained using (Bn2Cyclam)ZrX2 complexes and several hetero-
allenes [15]. An extension of this work to the chemistry of late
transition metals is presented here where the synthesis and char-
acterization of new copper(II) and zinc(II) complexes anchored by
trans-N,N0-disubstituted cyclams are described.
2. Results and discussion
Trans-N,N0-disubstituted cyclams of the type H2Bn2Cyclam
t
(Bn ¼ PhCH2 or 4 ꢀ BuPhCH2) react with one equiv. of zinc(II) or
* Corresponding author.
E-mail address: ana.martins@ist.utl.pt (A.M. Martins).
t
copper(II) salts to afford [{H2(4 ꢀ BuPhCH2)2Cyclam}Cu]SO4, 1,
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.11.015

L.G. Alves et al. / Journal of Organometallic Chemistry 760 (2014) 130e137
131
[{H2(PhCH2)2Cyclam}Cu]X, (X ¼ SO4, 2; X ¼ (CH3COO)2, 3),
[{H2(PhCH2)2Cyclam}Zn]SO4, 5, and [{H2(PhCH2)2Cyclam}ZnCl]Cl,
6, as shown in Scheme 1.
Scheme 1.
The IR spectra of complexes 1e3, 5 and 6 show that the ligand
frame bands are sensitive to metal complexation and deviate to
higher wavenumbers in comparison with the values obtained for
the free ligands. In the spectra of complexes 1, 2 and 5 strong bands
due to the sulphate ion are observed in the ranges 1103e1020 cmꢀ1
and 632e619 cmꢀ1 for the anti-symmetric stretching and bending
Fig. 1. a) ORTEP diagram of [{H2(PhCH2)2Cyclam}Cu(H2O)2]S, 4, showing thermal el-
lipsoids at 40% probability level. Half molecule is generated by symmetry. Selected
hydrogen atoms are omitted for clarity; b) Best view of 4 revealing the hydrogen bonds
between S(1) and H(1O), H(2O) and H(2N) atoms (dashed lines).
vibration modes, respectively. In complex 3, the nC
] band corre-
O
sponding to the acetate ion shows up at 1560 cmꢀ1. Complexes 1e3
are paramagnetic having magnetic moments of 1.6 MB, 1.8 MB and
1.9 MB, respectively, in agreement with the presence of a Cu(II)
metal center.
The coordination geometry of copper is octahedral. The equa-
torial plane is defined by the four nitrogen atoms of the cyclam ring
with internal NeCueN angles close to 90ꢁ and the axial positions
are occupied by two water molecules. The data obtained for com-
plex 4 are similar to those reported for other octahedral Cu(II)
complexes displaying cyclams and two axial water molecules [17],
The reaction of H2(PhCH2)2Cyclam with CuSO4$5H2O depends
on the solvent. If performed in methanol [{H2(PhCH2)2Cyclam}Cu]
SO4, 2, is the unique product obtained. When a mixture of CH3CN/
H2O is used as solvent, along with the formation of 2, few pink
crystals of [{H2(PhCH2)2Cyclam}Cu(H2O)2]S, 4, were also obtained.
The formation of 4 attests the reduction of SO24ꢀ to S2ꢀ and is
reminiscent of the biological role of enzymes in the SO24ꢀ/SO32ꢀ/S2ꢀ
reducing chain [16]. Complex 4 was identified by mass spectrom-
etry and single crystal X-ray diffraction. Its molecular structure is
shown in Fig. 1a and relevant distances and angles are shown in
Table 1. Crystallographic and experimental details of data collection
and crystal structure determination are presented in Table 4.
in
particular,
[H2{1,5,8,12-tetramethyl-1,8,11-tetraazacyclo
tetradecane}Cu(H2O)2]X (X ¼ NO2, Br, Cl, I) [17a]. The two benzyl
substituents are located at opposite sides of the cyclam ring
defining a trans-III configuration that corresponds to the most
stable diastereomer in octahedral cyclam complexes [18].
Hydrogen bonds are established between S(1) and the hydrogen
atoms H(1O), H(2O) and H(2N) with distances of 2.210, 2.315 and
ꢀ
2.323 A, respectively, as shown in Fig. 1b (see Table 2 for details).
Table 2
Table 1
ꢁ
ꢀ
Hydrogen bond distances (A) and angles ( ) of the compounds 4, 6, 7 and 9.
ꢁ
ꢀ
Selected distances (A) and angles ( ) of the compounds 4, 6, 7 and 9.
^
Compound
DeH/A
d (DeH)
d (H/A)
d (D/A)
(DHA)
Ligand set
Substituents
4
O(1)eH(1O)/S(1)
O(1)eH(2O)/S(1)
N(2)eH(2N)/S(1)
N(4)eH(4N)/Cl(2) 0.889
N(8)eH(8N)/Cl(4) 0.843
N(2)eH(2N)/O(5)
N(4)eH(4N)/O(6)
N(2)eH(2N)/Cl(1) 0.855
0.959
0.911
0.916
2.210
2.315
2.323
2.341
2.593
2.078
2.145
2.445
3.161
3.196
3.231
3.186
3.354
2.892
2.918
3.282
171.73
162.56
171.61
158.70
150.70
168.52
169.42
166.14
MeN(1)
MeN(2)
MeN(3)
MeN(4)
MeO
MeCl
4
2.094(2)
2.283(3)
2.333(4)
2.108(3)
2.113(2)
2.025(3)
1.992(2)
2.063(3)
2.052(4)
1.995(2)
2.000(3)
2.009(3)
e
e
2.670(4)
e
e
6a
6b
7a
7b
9
2.313(3)
2.295(3)
e
2.056(3)
2.065(3)
e
2.247(1)
2.235(1)
e
6a
6b
7a
7b
9
e
2.440(2)
2.395(2)
2.444(3)
0.825
0.783
e
e
e
2.040(3)
2.006(3)
2.846(3)
N
eqeMeN0eq
NeqeMeCleq
NeqeMeCleq
X
axeMeX0ax
The 1H NMR spectra of compounds [{H2(PhCH2)2Cyclam}Zn]
SO4, 5, and [{H2(PhCH2)2Cyclam}ZnCl]Cl, 6, display ten chemi-
cally non-equivalent resonances corresponding to the macro-
cyclic protons of the [C2] and [C3] cyclam chains in agreement
with average C2 symmetry. The benzyl protons are diaster-
eotopic and appear as AB systems exhibiting coupling constants
4
86.58(7)
120.9(1)
107.9(2)
86.6(1)
86.3(1)
85.6(1)
93.42(7)
180.00
6a
6b
7a
7b
9
118.6(1)
128.3(2)
e
e
e
120.5(1)
123.8(1)
e
e
e
159.6(1)
165.0(1)
180.00(8)
180.0
93.4(1)
93.7(1)
86.8(1)
151.27

132
L.G. Alves et al. / Journal of Organometallic Chemistry 760 (2014) 130e137
2JHeH of 19 and 15 Hz for 5 and 6, respectively. The 13C{1H} NMR
spectra are in conformity with the proton data showing six
resonances for the ligand methylene carbons and one set of
aromatic signals.
Crystals of complex 6 suitable for X-ray diffraction were ob-
tained from slow evaporation of an aqueous solution (crystallo-
graphic and experimental details are presented in Table 4).
Compound 6 crystallized in the triclinic space group P-1 with two
molecules in the asymmetric unit (6a and 6b). An ORTEP depiction
of the molecular structure of 6a is shown in Fig. 2 and relevant
distances and angles are presented in Table 1.
methanol. A comparable procedure was reported for the prepara-
tion of other copper cyclam derivatives using Cu(ClO4)2$6H2O [9].
Complex 9 is obtained independently of the reaction being per-
formed with one or two equiv. of CuCl2$2H2O.
The role of Cu2þ is critical for the outcome of the reactions once
it is only in the presence of copper that the bridging methylene
carbons are activated for nucleophilic attack by methanol.
In the IR spectra of complexes 7e9 the nNeH bands are observed
in the range 3159e2946 cmꢀ1. The nS
] bonds in 7 give rise to a
O
broad band at 1108e1020 cmꢀ1 and one sharp band at 620 cmꢀ1
and the nC
]
bands in 8 show up at 1622 and 1569 cmꢀ1
.
O
The magnetic moments of compounds 7e9 are 1.6 MB, 1.7 MB
and 2.1 Bohr magnetons, respectively, in agreement with their
formulations. The EPR spectra are shown in Fig. 3 and the experi-
mental spin Hamiltonian parameters are presented in Table 3.
Fig. 2. ORTEP diagram of [{H2(PhCH2)2Cyclam}ZnCl]Cl, 6a, showing thermal ellipsoids
at 35% probability level. Selected hydrogen atoms are omitted for clarity. Hydrogen
bond is represented by dashed line.
Fig. 3. First derivative X-band EPR spectra of compounds 7 (top), 8 (middle) and 9
(bottom) recorded at 77 K in ethyleneglycol.
The coordination geometry around the zinc is trigonal bipyra-
midal as observed in other pentacoordinated zinc cyclam com-
plexes [19]. The equatorial plane is defined by N(2), N(4) and Cl(1)
atoms. The axial positions are occupied by the other two nitrogen
atoms of the macrocycle with N(1)eZn(1)eN(3) angle of 159.6(1)ꢁ
in 6a and 165.0(1)ꢁ in 6b. In general, the distances and angles
determined for 6a and 6b are in agreement with values reported
[20]. The counter-ion is in the proximity of one NH group of the
cyclam ring with which it forms a Cl/H/N bridge (see Table 2 for
details).
In general, the spectra are typical of essentially tetragonal Cu(II)
complexes with a dx2ꢀy2 ground state (gz > gx, gy > ge) [21], which
means that in solution the copper is coordinated to the four ni-
trogen atoms of the cyclam ring and no bonding to either the
pending arms or the anions are observed.
Table 3
Experimental spin Hamiltonian parameters for compounds 7e9.a
gx, gy
(or gt
Ax, Ay (or At
)
gz
(or g )
Az (or A )
gz/Az cm
jj
The compounds presented in Scheme 2, with general formula
[{H2(MeOCH2)2Cyclam}Cu]X (X ¼ SO4, 7, (CH3COO)2, 8, and [CuCl4],
9) were obtained from reactions of 1,4,8,11-tetraazatricyclo
[9.3.1.14,8]hexadecane with the corresponding Cu(II) salts in
)
ꢂ 10ꢀ4 cmꢀ1
ꢂ 10ꢀ4 cmꢀ1
jj
7
8
2.045
2.067
2.013
2.094
2.060
15.3
16.9
21.7
1.9
2.190
2.187
193.9
200.2
112
109
9
2.190
2.385
200.0
139.0
109
171
1.1
[CuCl4]2-
a
EPR spectra measured at 77 K in ethyleneglycol.
The values of gz and Az for complexes 7e9 were plotted in a
PeisacheBlumberg [22] representation and are consistent with a
[CuN4] core in solution with gz/Az ratios of 112 cm for 7 and 109 cm
for 8 and 9 revealing that the geometry around the metal center is
square-planar for all complexes. In the case of 9, it is possible to
observe the hyperfine signals that are assigned to the [CuCl4]2ꢀ
counter-anion. The significantly higher gz/Az ratio found for the
[CuCl4]2ꢀ species is indicative of its tetrahedral geometry. More-
over, there is no observable indication of spinespin coupling be-
tween [CuN4] and [CuCl4]2ꢀ cores.
Crystals of 7 and 9 were obtained from slow evaporation of
methanol solutions at room temperature. Compounds 7 and 9
crystallized in the monoclinic P21/n space group. The asymmetric
unit of 7 displays two molecules (7a and 7b). Relevant distances
Scheme 2.
and angles are shown in Table 1 and crystallographic and

L.G. Alves et al. / Journal of Organometallic Chemistry 760 (2014) 130e137
133
experimental details of data collection and crystal structure de-
terminations are presented in Table 4.
bridges the metal centers of the cation and the anion. The angle
O(2)eCu(1)e(Cl3_$1) deviates from linearity with a value of
Table 4
Crystal data and structure refinement for complexes 4, 6, 7 and 9.
Compound
4
6
7$(CH3OH)2
9
Empirical formula
Formula weight
Temperature (K)
Wavelength (A)
Crystal system
Space group
C24H40CuN4O2S2
544.29
150
0.71073
Monoclinic
P21/c
C24H36Cl2N4Zn
516.86
302
0.71073
Triclinic
P-1
C16H40CuN4O8S
512.14
150
0.71073
Monoclinic
P21/n
C14H32Cl4Cu2N4O2
557.34
150
0.71073
Monoclinic
P21/n
ꢀ
Unit cell dimensions:
ꢀ
a (A)
9.8760(4)
9.8668(5)
13.2932(6)
90
94.243(2)
90
1291.8(1)
2
1.399
9.584(1)
12.661(1)
23.035(3)
88.848(4)
82.146(4)
68.358(4)
2572.3(5)
4
11.291(1)
13.327(1)
17.455(2)
90
98.260(4)
90
2599.3(4)
4
10.026(3)
15.934(2)
14.438(2)
90
95.93(1)
90
2294.2(8)
4
ꢀ
b (A)
ꢀ
c (A)
a
(ꢁ)
(ꢁ)
b
g
(ꢁ)
3
ꢀ
Volume (A )
Z
Calculated density (g mꢀ3
)
1.335
1.181
1088
1.309
0.963
1092
1.613
2.336
1144
Absorption coefficient (mmꢀ1
F (000)
)
1.036
578
Crystal size (mm)
0.08 ꢂ 0.10 ꢂ 0.20
0.20 ꢂ 0.20 ꢂ 0.20
2.32e25.38
ꢀ11 ꢃ h ꢃ 11, ꢀ15 ꢃ k ꢃ 15,
ꢀ27 ꢃ l ꢃ 27
80,203/9444 [0.0373]
0.30 ꢂ 0.30 ꢂ 0.30
0.02 ꢂ 0.06 ꢂ 0.10
Theta range for data collection (ꢁ) 2.57e29.60
1.93e27.21
1.91e25.77
Limiting indices
ꢀ13 ꢃ h ꢃ 13, ꢀ13 ꢃ k ꢃ 13,
ꢀ14 ꢃ h ꢃ 14, ꢀ15 ꢃ k ꢃ 17,
ꢀ22 ꢃ l ꢃ 22
39,447/5756 [0.0352]
ꢀ12 ꢃ h ꢃ 12, ꢀ19 ꢃ k ꢃ 19,
ꢀ17 ꢃ l ꢃ 17
28,985/4365 [0.0695]
ꢀ18 ꢃ l ꢃ 18
Reflections collected/unique [Rint
]
23,227/3631 [0.0497]
Completeness to
Refinement method
q
(%)
99.9 (
q
¼ 29.60)
99.5 (
q
¼ 25.38)
99.1 (
q
¼ 27.21)
99.1 (
q
¼ 25.77)
Full-matrix least squares on F2 Full-matrix least squares on F2 Full-matrix least squares on F2 Full-matrix least squares on F2
Data/restraints/parameters
3631/0/163
1.087
R1 ¼ 0.0390, wR2 ¼ 0.1158
R1 ¼ 0.0507, wR2 ¼ 0.1211
Multi-scan
1.182 and ꢀ0.609
9444/0/569
1.047
R1 ¼ 0.0596, wR2 ¼ 0.1580
R1 ¼ 0.0695, wR2 ¼ 0.1656
Multi-scan
1.669 and ꢀ1.390
5756/0/288
1.055
R1 ¼ 0.0472, wR2 ¼ 0.1246
R1 ¼ 0.0648, wR2 ¼ 0.1326
Multi-scan
0.931 and ꢀ0.676
4365/0/244
1.058
R1 ¼ 0.0409, wR2 ¼ 0.0815
R1 ¼ 0.0645, wR2 ¼ 0.0877
Multi-scan
0.711 and ꢀ0.422
Goodness-of-fit on F2
Final R indices [I > 2
R indices (all data)a
s
(I)]a
Absorption correction
Largest diff. peak/hole (e A
ꢀꢀ3
)
a
R1 ¼ SjjF0j ꢀ jFcjj/SjF0j; wR2 ¼ {S[w(F20 e Fc2)2]/S[w(F02)2]}1/2
.
The molecular structures of complexes 7 and 9 show that the
SO24ꢀ anions and [CuCl4]2ꢀ have a determining role in the solid state
conformations of the macrocycle ring as well as in the supramo-
lecular structures adopted by the complexes, as discussed below.
Compound 7 reveals a linear polymeric structure growing in the
b direction as shown in Fig. 4a. The average planes defined by two
consecutive cyclam rings of molecules 7a and 7b define dihedral
angles of 31.30ꢁ, leading to a zigzag arrangement (Fig. 4b). This
supramolecular architecture is maintained by hydrogen bonds be-
tween the oxygen atoms of the sulphate anion and NH groups of
the macrocyclic rings (see details in Table 2).
The coordination of copper is octahedral with four nitrogen
atoms of the macrocycle defining the equatorial plane and two
oxygen atoms of sulphate ions at the axial positions (Fig. 4c). The
CueN and CueO bond distances are within the ranges observed for
other compounds [20]. The N-CH2OMe pending arms attached to
the trans-nitrogen atoms of the cyclam ring point in opposite di-
rections in relation to the average [N4] plane resulting in trans-II
conformation of the complex [18].
151.27ꢁ. The [CuCl4]2ꢀ anions are responsible for the polymeric
arrangement observed in the crystal. One hydrogen bond between
a NH group of cyclam and the Cl(1) atom of [CuCl4]2ꢀ and a chlorine
bridge between the cation and another [CuCl4]2ꢀ anion originate a
chain with alternating cations and anions. The Cu(1)eCl(3_$1)e
Cu(2_$1) bridge is very asymmetric with the Cu(1)eCl(3_$1) bond
much longer than Cu(2_$1)eCl(3_$1). The latter bond distance is
also longer than the terminal CueCl bonds in the anion, in agree-
ment with its bridging position between the two copper centers.
Copper compounds have been used as catalyst for the click reac-
tion between aryl halides, sodium azide and terminal alkynes leading
to the synthesis of triazoles [24]. An alternative procedure for click
reactions was described using aryl boronic acids, sodium azide and
terminal alkynes [25]. Using the latter procedure, preliminary tests
revealed that complex [{H2(MeOCH2)2Cyclam}Cu]SO4, 7, is an effi-
cient catalyst for the preparation of methyl 1-(4-methoxyphenyl)-
1H-1,2,3-triazole-4-carboxylate according to Equation (1). The reac-
tion led to the quantitative and selective formation of the 1,4-isomer
in 24 h at 55 ꢁC.
The supramolecular arrangement in 9 is shown in Fig. 5a and an
ORTEP view of the molecular structure is presented in Fig. 5b. The
complex shows a trans-III conformation with the two N-CH2OMe
pending arms directed to the same side of the average nitrogen
plane of cyclam [18]. The coordination geometry of copper is dis-
torted octahedral in the cation and tetrahedral in the anion. The
equatorial plane of the cation is defined by the four nitrogen atoms
of the cyclam ring and presents very regular CueN bond lengths
and NeCueN angles, in agreement with other copper cyclam
complexes [6b,17a,23]. The two axial positions are occupied by the
oxygen atom of one CH2OMe group and by a chlorine atom that
ð1Þ

134
L.G. Alves et al. / Journal of Organometallic Chemistry 760 (2014) 130e137
Fig. 5. a) View along c of the supramolecular arrangement in compound 9: the chain
grows in the a direction. Hydrogen bonds are shown as dashed lines; b) ORTEP dia-
gram of [{H2(MeOCH2)2Cyclam}Cu][CuCl4], 9, showing thermal ellipsoids at 40%
probability level. Selected hydrogen atoms are omitted for clarity.
EPR spectra were recorded at 77 K (on glasses made by freezing
solutions in liquid nitrogen) in a Bruker ESP 300E X-band spec-
trometer at IST. The measured spectra (1st derivative X-band EPR)
were simulated with the EPR simulation software developed by
Rockenbauer and Korecz [26]. Magnetic Susceptibility was
measured at 298 K on a Magway MSB Mk1 Magnetic Susceptibility
Balance at IST.
3.2. Synthetic procedures
Fig. 4. a) View along a of the supramolecular arrangement in compound 7: the chain
grows in the b direction. Hydrogen bonds are shown by dashed lines; b) View of
dihedral angles between the average [N4] planes of 7a and 7b creating a zigzag
arrangement; c) ORTEP diagram of [{H2(MeOCH2)2Cyclam}Cu]SO4, 7a, showing ther-
mal ellipsoids at 40% probability level. Half molecule is generated by symmetry.
Selected hydrogen atoms are omitted for clarity.
t
3.2.1. Synthesis of [{H2(4 ꢀ BuPhCH2)2Cyclam}Cu]SO4 (1)
t
H2(4 ꢀ BuPhCH2)2Cyclam (0.50 g, 1.01 mmol) was dissolved in
50 mL of MeOH and one equiv. of CuSO4$5H2O (0.25 g, 1.01 mmol)
was added at room temperature. The blue solution turned violet
and it was left stirring for 4 h. After filtration and evaporation of the
solvent to dryness, the compound was obtained as a violet solid in
3. Experimental section
81% yield (0.58 g, 0.82 mmol). Anal. calcd for
C32H52Cu-
N4O4S$3H2O: C, 54.41; H, 8.28; N, 7.93; S, 4.54. Found: C, 54.93; H,
3.1. General considerations
8.17; N, 7.62; S, 4.64. FT-IR (KBr, cmꢀ1): 3127 (nNH), 1119, 1078 and
620 (nSO4). cm ¼ 1.0 ꢂ 10ꢀ3 cgs (
¼ 1.6 Bohr magnetons).
m
t
H2(PhCH2)2Cyclam, H2(4 ꢀ BuPhCH2)2Cyclam and 1,4,8,11-
tetraazatricyclo[9.3.1.14,8]hexadecane were prepared according to
described procedures [8,13a]. All other reagents were commercial
grade and used without further purification. NMR spectra were
recorded in a Bruker AVANCE II 400 MHz spectrometer, at 296 K
unless stated otherwise, referenced internally to residual proton-
solvent (1H) or solvent (13C) resonances, and reported relative to
tetramethylsilane (0 ppm). 1He13C{1H} HSQC NMR experiments
were performed in order to make all the assignments. Elemental
analyses were obtained from Laboratório de Análises do IST. FT-IR
spectra were recorded on a Jasco FT/IR-4100 spectrometer at IST.
3.2.2. Synthesis of [{H2(PhCH2)2Cyclam}Cu]SO4 (2) and
[{H2(PhCH2)2Cyclam}Cu(H2O)2]S (4)
Method A: H2(PhCH2)2Cyclam (0.50 g, 1.32 mmol) was dissolved
in 50 ml of CH3CN/H2O (3:1) and one equiv. of CuSO4.5H2O (0.33 g,
1.32 mmol) was added at room temperature. The blue solution
turned dark violet and it was left stirring for 4 h. After filtration, the
solution was concentrated until a minimal volume and stored at
room temperature. Compound 2 was obtained as a dark violet
powder from slow evaporation of the solvent in 72% yield (0.53 g,

L.G. Alves et al. / Journal of Organometallic Chemistry 760 (2014) 130e137
135
0.95 mmol). Few pink crystals of [{H2(PhCH2)2Cyclam}Cu(H2O)2]S,
4, were also obtained.
2.32 mmol). Anal. calcd for C14H32CuN4O6S$H2O: C, 36.08; H, 7.35;
N, 12.02. Found: C, 35.68; H, 7.56; N, 12.96. FT-IR (KBr, cmꢀ1): 3227
Method B: H2(PhCH2)2Cyclam (0.50 g, 1.32 mmol) was dissolved
in 50 ml of MeOH and one equiv. of CuSO4$5H2O (0.33 g,1.32 mmol)
was added at room temperature. The blue solution turned dark
violet and it was left stirring for 4 h. After filtration, the solution was
evaporated to dryness affording compound 2 as a dark violet
powder in 82% yield (0.61 g, 1.09 mmol). Anal. calcd for
(
nNeH), 1120 (nSO4). cm ¼ 1.1 ꢂ 10ꢀ3 cgs (
¼ 1.6 Bohr magnetons).
m
3.2.7. Synthesis of [{H2(MeOCH2)2Cyclam}Cu](CH3COO)2 (8)
1,4,8,11-tetraazatricyclo[9.3.1.14,8]hexadecane (1.00
g,
4.46 mmol) was dissolved in 75 mL of MeOH and two equiv. of
Cu(CH3COO)2$H2O (0.82 g, 4.11 mmol) was added. The mixture was
stirred for three days at room temperature. After filtration and
evaporation of the solvent to dryness, the compound was obtained
as a blue solid in 58% yield (1.30 g, 2.57 mmol). Anal. calcd for
C
24H36CuN4O4S$H2O: C, 51.64; H, 6.86; N, 10.04; S, 5.74. Found: C,
51.51; H, 6.84; N, 10.09; S, 5.69. FT-IR (KBr, cmꢀ1): 3091 (nNH), 1119,
1094, 1067 and 619 (nSO4). cm ¼ 1.3 ꢂ 10ꢀ3 cgs (
m
¼ 1.8 Bohr
magnetons).
C
18H38CuN4O6$2H2O: C, 42.72; H, 8.36; N, 11.07. Found: C, 42.95; H,
7.01; N, 11.05. FT-IR (KBr, cmꢀ1): 3163 (nNeH). cm ¼ 1.2 ꢂ 10ꢀ3 cgs
3.2.3. Synthesis of [{H2(PhCH2)2Cyclam}Cu](CH3COO)2 (3)
(m
¼ 1.7 Bohr magnetons).
H2(PhCH2)2Cyclam (0.50 g, 1.32 mmol) was dissolved in 50 ml of
CH3CN/H2O (3:1) and one equiv. of Cu(CH3COO)2$H2O (0.26 g,
1.32 mmol) was added at room temperature. The blue solution
turned violet and it was left stirring for 4 h. After filtration, the
solution was concentrated until a minimal volume and stored at
room temperature. A violet powder was obtained from slow
evaporation of the solvent in 85% yield (0.67 g, 1.12 mmol). Anal.
calcd for C28H42CuN4O4.2H2O: C, 56.22; H, 7.75; N, 9.37. Found: C,
56.79; H, 7.42; N, 9.31. FT-IR (KBr, cmꢀ1): 3141, 3064 (nNH), 1560
3.2.8. Synthesis of [{H2(MeOCH2)2Cyclam}Cu][CuCl4] (9)
1,4,8,11-tetraazatricyclo[9.3.1.14,8]hexadecane (1.00
g,
4.46 mmol) was dissolved in 80 mL of MeOH and two equiv. of
CuCl2$2H2O (1.56 g, 9.15 mmol) was added. The mixture was stirred
for five days at room temperature. After filtration and evaporation
of the solvent to dryness, the compound was obtained as a brown
semi-crystalline solid in 69% yield (1.72 g, 3.09 mmol). Anal. calcd
for C14H32Cl4Cu2N4O2: C, 30.17; H, 5.79; N,10.05. Found: C, 29.91; H,
5.90; N, 9.81. FT-IR (KBr, cmꢀ1): 3159 (nNeH). cm ¼ 1.8 ꢂ 10ꢀ3 cgs
(
nCO). cm ¼ 1.5 ꢂ 10ꢀ3 cgs (
¼ 1.9 Bohr magnetons).
m
(m
¼ 2.1 Bohr magnetons).
3.2.4. Synthesis of [{H2(PhCH2)2Cyclam}Zn]SO4 (5)
H2(PhCH2)2Cyclam (0.50 g, 1.32 mmol) was dissolved in 50 ml of
CH3CN/H2O (3:1) and one equiv. of ZnSO4$7H2O (0.33 g, 1.32 mmol)
was added at room temperature. A white powder was obtained
after filtration in 62% yield (0.38 g, 0.70 mmol). Anal. calcd for
3.2.9. Catalytic procedure for the synthesis of methyl 1-(4-
methoxyphenyl)-1H-1,2,3-triazole-4-carboxylate
4-methoxyboronic acid (75 mg, 0.49 mmol) and sodium azide
(48 mg, 0.74 mmol) were dissolved in methanol and compound 7
(10%) was added. The mixture was stirred for 2.5 h at 55 ꢁC. Methyl
propiolate (0.13 mL, 1.46 mmol) and sodium ascorbate (10 mg,
0.05 mmol) were added. The mixture was stirred overnight at 55 ꢁC.
The crude was chromatographed by silica gel using an ethylacetate/
hexanes (1:3) mixture as eluent. The product was obtained as a
white solid (107 mg, 0.46 mmol) after evaporation of the solvent to
dryness and characterized by NMR spectroscopy. 1H NMR (CDCl3,
C
24H36N4O4SZn: C, 53.18; H, 6.69; N, 10.34; S, 5.92. Found: C, 55.23;
H, 7.41; N, 10.65; S, 4.62. FT-IR (KBr, cmꢀ1): 3192 (nNH), 1103, 632
nSO). 1H NMR (DMSO-d6/D2O, 400.1 MHz, 296 K):
(ppm) 7.44e
(
d
2
7.31 (overlapping, 10H total, PhCH2N), 4.33 (d, 2H, JHeH ¼ 19 Hz,
PhCH2N), 4.20 (d, 2H, 2JHeH ¼ 19 Hz, PhCH2N), 3.34 (m, 2H, CH2N),
3.23 (m, 2H, CH2N), 3.15e3.03 (overlapping, 4H total, CH2N), 2.91
(m, 2H, CH2N), 2.78 (m, 2H, CH2N), 2.56 (m, 2H, CH2N), 2.43 (m, 2H,
CH2N), 1.92e1.81 (overlapping, 4H total, CH2CH2CH2). 13C{1H} NMR
300 MHz, 296 K):
Ph), 6.99 (d, J ¼ 8 Hz, 2H, m-Ph), 3.94 (s, 3H, CH3), 3.82 (s, 3H, CH3);
1H NMR (CD3OD, 500 MHz, 296 K):
(ppm) 9.01 (s, 1H, CH), 7.78 (d,
2H, o-Ph), 7.12 (d, 2H, m-Ph), 3.95 (s, 3H, CH3), 3.88 (s, 3H, CH3); 13
{1H} NMR (CD3OD, 125 MHz, 296 K):
(ppm) 162.3 (COOCH3), 162.0
d
(ppm) 8.40 (s, 1H, CH), 7.60 (d, J ¼ 8 Hz, 2H, o-
(DMSO-d6/D2O, 100.6 MHz, 296 K):
d (ppm) 132.8 (PhCH2N), 131.2
(PhCH2N), 129.7 (PhCH2N), 129.3 (PhCH2N), 55.6 (PhCH2N), 53.7
(CH2N), 53.5 (CH2N), 50.8 (CH2N), 46.4 (CH2N), 24.0 (CH2CH2CH2).
d
C
d
3.2.5. Synthesis of [{H2(PhCH2)2Cyclam}ZnCl]Cl (6)
(NCCOOCH3), 141.1 (Ph), 131.1 (Ph), 127.7 (NCH), 123.5 (Ph), 116.6
(Ph), 56.2 (OCH3), 52.6 (COOCH3).
An aqueous solution of ZnCl2 (0.18 g, 1.32 mmol) was added to a
solution of H2(PhCH2)2Cyclam (0.50 g, 1.32 mmol) in 50 ml of
CH3CN. A white powder was obtained after filtration in 61% yield
(0.12 g, 0.16 mmol). Anal. calcd for C24H36Cl2N4Zn: C, 55.77; H, 7.02;
N, 10.84. Found: C, 54.91; H, 7.42; N, 10.70. FT-IR (KBr, cmꢀ1): 3132,
3.3. General procedures for X-ray crystallography
3028 (nNH). 1H NMR (DMSO-d6/D2O, 400.1 MHz, 296 K):
d
(ppm)
Crystallographic and experimental details of data collection and
crystal structure determinations for the four compounds are
available in Table 3. Suitable crystals of compounds 4, 6, 7 and 9
2
7.69e7.55 (overlapping, 10H total, PhCH2N), 4.41 (d, 2H, JHe
¼ 15 Hz, PhCH2N), 4.35 (d, 2H, 2JHeH ¼ 15 Hz, PhCH2N), 3.45e3.36
H
(overlapping, 4H total, CH2N), 3.18e2.94 (overlapping, 8H total,
CH2N), 2.75 (m, 2H, CH2N), 2.63e2.53 (overlapping, 4H total, CH2N
and CH2CH2CH2), 1.99 (m, 2H, CH2CH2CH2). 13C{1H} NMR (DMSO-
were coated and selected in FomblinÒ oil. Data were collected using
ꢀ
graphite monochromated Mo-K
a
radiation (
l
¼ 0.71073 A) on a
Bruker AXS-KAPPA APEX II diffractometer. Cell parameters were
retrieved using Bruker SMART software and refined using Bruker
SAINT on all observed reflections [27]. Absorption corrections were
applied using SADABS [28]. The structures were solved by direct
methods using SIR92 [29], SIR97 [30] or SIR2004 [31]. Structure
refinement was done using SHELXL-97 [32]. These programs are
part of the WinGX software package version 1.80.05 [33]. The
hydrogen atoms of the NH groups were located in the electron
density map. The other hydrogen atoms were inserted in calculated
positions and allowed to refine in the parent atoms. Torsion angles,
mean square planes and other geometrical parameters were
calculated using SHELX [32]. Illustrations of the molecular
d6/D2O, 100.6 MHz, 296 K):
(2 ꢂ PhCH2N), 57.2 (PhCH2N), 54.7 (2 ꢂ CH2N), 52.2 (CH2N), 47.5
(CH2N), 25.5 (CH2CH2CH2).
d
(ppm) 134.0 (2 ꢂ PhCH2N), 130.8
3.2.6. Synthesis of [{H2(MeOCH2)2Cyclam}Cu](SO4) (7)
1,4,8,11-tetraazatricyclo[9.3.1.14,8]hexadecane
(1.00
g,
4.46 mmol) was dissolved in 80 mL of MeOH and two equiv. of
CuSO4$5H2O (1.14 g, 4.56 mmol) was added. The mixture was
stirred for five days at room temperature. After filtration and
evaporation of the solvent to dryness, the compound was obtained
as
a dark blue semi-crystalline solid in 52% yield (1.08 g,

136
L.G. Alves et al. / Journal of Organometallic Chemistry 760 (2014) 130e137
(g) M.J.L. Tendero, A. Benito, J. Cano, J.M. Lloris, R. Martinezmanez, J. Soto,
A.J. Edwards, P.R. Raithby, M.A. Rennie, J. Chem. Soc. Chem. Commun. (1995)
1643e1644;
(h) P. Comba, P. Jurisic, Y.D. Lampeka, A. Peters, A.I. Prikhod’ko, H. Pritzkow,
Inorg. Chim. Acta 324 (2001) 99e107.
structures were made with Mercury 3.0 [34] or ORTEP-3 [35] for
Windows.
Compounds 6, 7 and 9 crystallized with disordered molecules of
solvent. As all attempts to model the disorder did not lead to
acceptable solutions, the Squeeze/PLATON [36] sequence was
applied.
[7] (a) C.J. Anderson, M.J. Welch, J. Chem. Rev. 99 (1999) 2219e2234;
(b) L.M.P. Lima, D. Esteban-Gómez, R. Delgado, C. Platas-Iglesias, R. Tripier,
Inorg. Chem. 51 (2012) 6916e6927;
(c) C.L. Schmid, M. Neuburger, M. Zehnder, T.A. Kaden, K. Bujno, R. Bilewicz,
Helv. Chim. Acta 80 (1997) 241e252;
(d) E. Asato, S. Hashimoto, N. Matsumoto, S. Kida, J. Chem. Soc. Dalton Trans.
(1990) 1741e1746;
Acknowledgements
(e) G. Vuckovic, M. Antonijevic, D. Poleti, J. Serb. Chem. Soc. 67 (2002) 677e
684;
(f) S. Wada, K. Saka, D. Yoshioka, M. Mikuriya, Bull. Chem. Soc. Jpn. 83 (2010)
364e374;
The authors thank Fundação para a Ciência e a Tecnologia,
Portugal, for funding (PEst-OE/QUI/UI0100/2013, SFRH/BPD/86815/
2012).
(g) M.R. Oberholzer, M. Neuburger, M. Zehnder, T.A. Kaden, Helv. Chim. Acta
78 (1995) 505e513.
[8] G. Royal, V. Dahaoui-Gindrey, S. Dahaoui, A. Tabard, R. Guilard, P. Pullumbi,
C. Lecomte, Eur. J. Org. Chem. (1998) 1971e1975.
Appendix A. Supplementary material
[9] (a) S.-G. Kang, J.K. Kweon, Y.H. Lee, J.-S. Kim, U. Lee, Bull. Korean Chem. Soc. 28
(2007) 489e492;
(b) G.R. Jeong, S.-G. Kang, J.H. Jeong, Inorg. Chim. Acta 379 (2011) 64e69.
[10] L.G. Alves, A.M. Martins, M.T. Duarte, J. Mol. Struct. 1026 (2012) 168e173.
[11] L. Maria, I.C. Santos, L.G. Alves, J. Marçalo, A.M. Martins, J. Organomet. Chem.
728 (2013) 57e67.
CCDC 965244e965247 contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif.
[12] (a) R.F. Munhá, S. Namorado, S. Barroso, M.T. Duarte, J.R. Ascenso, A.R. Dias,
A.M. Martins, J. Organomet. Chem. 691 (2006) 3853e3861;
(b) R.F. Munhá, L.G. Alves, N. Maulide, M.T. Duarte, I.E. Markó, M.D. Fryzuk,
A.M. Martins, Inorg. Chem. Commun. 11 (2008) 1177e1179;
(c) R.F. Munhá, M.A. Antunes, L.G. Alves, L.F. Veiros, M.D. Fryzuk, A.M. Martins,
Organometallics 29 (2010) 3753e3764;
References
[1] (a) S. Sreedaran, K.S. Bharathi, A.K. Rahiman, K. Rajesh, G. Nirmala,
V. Narayanan, J. Coord. Chem. 61 (2008) 3594e3609;
(b) E. Kimura, X.-H. Bu, M. Shionoya, S.J. Wada, S. Maruyama, Inorg. Chem. 31
(1992) 4542e4546;
(d) R.F. Munhá, L.F. Veiros, M.T. Duarte, M.D. Fryzuk, A.M. Martins, Dalton
Trans. (2009) 7494e7508;
(e) R.F. Munhá, J. Ballmann, L.F. Veiros, B.O. Patrick, M.D. Fryzuk, A.M. Martins,
Organometallics 31 (2012) 4937e4940.
(c) S. Itok, M. Kitamura, Y. Yamada, S. Aoki, Chem. Eur. J. 15 (2009) 10570e
10584;
(d) B. Castano, T. Pedrazzini, M. Sisti, E. Gallo, F. Ragaini, N. Casati, A. Caselli,
Appl. Organomet. Chem. 25 (2011) 824e829.
[13] (a) L.G. Alves, M.A. Antunes, I. Matos, R.F. Munhá, M.T. Duarte, A.C. Fernandes,
M.M. Marques, A.M. Martins, Inorg. Chim. Acta 363 (2010) 1823e1830;
(b) L.G. Alves, F. Hild, R.F. Munhá, L.F. Veiros, S. Dagorne, A.M. Martins, Dalton
Trans. 41 (2012) 14288e14298.
[14] M.A. Antunes, R.F. Munhá, L.G. Alves, L. Schafer, A.M. Martins, J. Organomet.
Chem. 696 (2011) 2e6.
[15] L.G. Alves, A.M. Martins, Inorg. Chem. 51 (2012) 11e12.
[16] D. Voet, J.G. Voet, Biochemistry, John Wiley & Sons, Inc., U.S.A., 1995.
[17] (a) T.H. Lu, S.C. Lin, H. Aneetha, K. Panneerselvam, C.S. Chung, J. Chem. Soc.
Dalton Trans. (1999) 3385e3391;
(b) K.-Y. Choi, I.-H. Suh, J.C. Kim, Bull. Korean Chem. Soc. 18 (1997) 1321e
1323.
[18] (a) B. Bosnick, C.K. Poon, M.L. Tobe, Inorg. Chem. 4 (1965) 1102e1108;
(b) P.O. Whimp, N.F. Curtis, M.F. Bailey, J. Chem. Soc. A Inorg. Phys. Theor.
(1970) 1956e1963;
(c) M.A. Donnelly, M. Zimmer, Inorg. Chem. 38 (1999) 1650e1658.
[19] (a) J. Notni, H. Gorls, E. Anders, Eur. J. Inorg. Chem. (2006) 1444e1455;
(b) T.G. Roy, S.K.S. Hazari, B. Dey, B.C. Nath, A. Dutta, F. Olbrich, D. Rehder,
Inorg. Chim. Acta 371 (2011) 63e70;
[2] (a) Y. Dong, S. Farquhar, K. Gloe, L.F. Lindoy, B.R. Rumbel, P. Turner,
K. Wichmann, Dalton Trans. (2003) 1558e1566;
(b) M. Shionoya, E. Kimura, Y.J. Iitaka, J. Am. Chem. Soc. 112 (1990) 9237e
9245;
(c) E. Kimura, Y. Kurogi, T. Koike, M. Shionoya, Y.J. Iitaka, Coord. Chem. 28
(1993) 33e49;
(d) E. Kimura, Y. Kurogi, T. Takahashi, Inorg. Chem. 30 (1991) 4117e4121.
[3] (a) Y. Al Shihadeh, A. Benito, J.M. Lloris, R. Martínez-Máñez, T. Pardo, J. Soto,
M.D. Marcos, J. Chem. Soc. Dalton Trans. (2000) 1199e1205;
(b) L. Fabbrizzi, M. Licchelli, P. Pallavicini, D. Sacchi, Supramol. Chem. 13
(2001) 569e582;
(c) Z.H. Zeng, L. Spiccia, Chem. Eur. J. 15 (2009) 12941e12944.
[4] (a) X. Liang, P. Sadler, Chem. Soc. Rev. 33 (2004) 246e266;
(b) J.D. Silversides, C.C. Allan, S.J. Archibald, Dalton Trans. (2007) 971e978;
(c) T.J. Wadas, E.H. Wong, G.R. Weisman, C.J. Anderson, Curr. Pharm. Des. 13
(2007) 3e16;
(d) Y. Inouye, T. Kanamori, M. Sugiyama, T. Yoshida, T. Koike, M. Shionoya,
K. Enomoto, K. Suehiro, E. Kimura, Antivir. Chem. Chemother. 6 (1995) 337e
344;
(e) S. Murugesan, S.J. Shetty, T.S. Srivastava, O.P.D. Noronha, A.M. Samuel,
Appl. Radiat. Isot. 55 (2001) 641e742;
(f) D.E. Reichert, J.S. Lewis, C.J. Anderson, Coord. Chem. Rev. 184 (1999) 3e66;
(g) L. Thunus, R. Lejeune, Coord. Chem. Rev. 184 (1999) 125e155;
(h) S.K.S. Hazari, T.G. Roy, B.K. Dey, S.C. Das, E.R.T. Tiekink, Met.-Based Drugs 4
(1997) 255e265;
(i) M. Demirbilek, E. Piskin, Hacet. J. Biol. Chem. 36 (2008) 263e271;
(j) L.O. Gerlach, J.S. Jakobsen, K.P. Jensen, M.R. Rosenkilde, R.T. Skerlj, U. Ryde,
G.J. Bridger, T.W. Schwartz, Biochemistry 42 (2003) 710e717;
(k) T.M. Hunter, I.W. McNae, X. Liang, J. Bella, S. Parsons, M.D. Walkinshaw,
P.J. Sadler, Proc. Natl. Acad. Sci. 102 (2005) 2288e2292;
(l) J.A. Esté, C. Cabrera, E. De Clercq, S. Struyf, J. Van Damme, G. Bridger,
R.T. Skerlj, M.J. Abrams, G. Henson, A. Gutierrez, B. Clotet, D. Schols, Mol.
Pharmacol. 55 (1999) 67e73.
(c) T.G. Roy, S.K.S. Hazari, K.K. Barua, E.R.T. Tiekink, Acta Crystallogr. E67
(2011) m1659em1660;
(d) K.-Y. Choi, I.-H. Suh, Main Group Met. Chem. 22 (1999) 123;
(e) K. Panneerselvam, T.-H. Lu, T.-Y. Chi, S.-F. Tung, C.-S. Chung, Anal. Sci. 15
(1999) 205e206.
[20] A.G. Orpen, L. Brammer, F.H. Allen, O. Kennard, D.G. Watson, R. Taylor, J. Chem.
Soc. Dalton Trans. (1989) S1eS83.
[21] (a) B.J. Hathaway, A.A.G. Tomlinson, Coord. Chem. Rev. 5 (1970) 1e43;
(b) I.M. Procter, B.J. Hathaway, P. Nicholls, J. Chem. Soc. A (1968) 1678e1684;
(c) S. Antosik, N.M.D. Brown, A.A. McConnel, A.L. Porte, J. Chem. Soc. A (1969)
545e550;
(d) F.J. Boas, R.H. Dunhill, J.R. Pilbrow, R.C. Sirvastava, T.D. Smith, J. Chem. Soc.
A (1969) 94e108.
[22] U. Sakaguchi, A.W. Addison, J. Chem. Soc. Dalton Trans. (1979) 600e608.
[23] (a) K. Panneerselvam, T.-H. Lu, S.-F. Tung, T.-Y. Chi, C. Pariya, C.-S. Chung, Anal.
Sci. 14 (1998) 1031e1032;
[5] J.A. McCleverty, T.J. Meyer, Comprehensive Coordination Chemistry II, vol. 1,
Elsevier, U.K., 2004.
[6] (a) A.M. Appel, R. Newell, D.L. DuBois, M.R. DuBois, Inorg. Chem. 44 (2005)
3046e3056;
(b) K. Panneerselvam, T.-H. Lu, T.-Y. Chi, F.-L. Liao, C.-S. Chung, Anal. Sci. 16
(2000) 439e440.
[24] (a) A.K. Feldman, B. Colasson, V.V. Fokin, Org. Lett. 6 (2004) 3897e3899;
(b) J. Andersen, S. Bolvig, X.F. Liang, Synlett (2005) 2941e2947;
(c) Y.B. Zhao, Z.Y. Yan, Y.M. Liang, Tetrahedron Lett. 47 (2006) 1545e1549.
[25] C.-Z. Tao, X. Cui, J. Li, A.-X. Liu, L. Liu, Q.-X. Guo, Tetrahedron Lett. 48 (2007)
3525e3529.
[26] A. Rockenbauer, L. Korecz, Appl. Magn. Reson. 10 (1996) 29e43.
[27] SAINT. Version 7.03A, Bruker AXS Inc., Madison. Wisconsin, USA, 1997e2003.
[28] G.M. Sheldrick, SADABS, Program for Empirical Absorption Corrections, Uni-
versity of Göttingen, Göttingen, Germany, 1996.
(b) Y. Dong, G.A. Lawrance, L.F. Lindoy, P. Turner, Dalton Trans. (2003) 1567e
1576;
(c) J.D. Silversides, C.C. Allan, S.J. Archibald, Dalton Trans. (2007) 971e978;
(d) E. Maimon, I. Zilbermann, G. Golub, A. Ellern, A.I. Shames, H. Cohen,
D. Meyerstein, Inorg. Chim. Acta 324 (2001) 65e72;
(e) A. Channa, J.W. Steed, Dalton Trans. (2005) 2455e2461;
(f) G. Kickelbick, T. Pintauer, K. Matyjaszewski, New J. Chem. 26 (2002) 462e
468;

L.G. Alves et al. / Journal of Organometallic Chemistry 760 (2014) 130e137
137
[29] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, J. Appl. Crystallogr. 26
[32] G.M. Sheldrick, Acta Crystallogr. A64 (2008) S112eS122.
(1993) 343e350.
[33] L.J. Farrugia, J. Appl. Crystallogr. 32 (1999) 837.
[30] A. Altomare, M.C. Burla, M. Camalli, G.L. Cascarano, C. Giacovazzo,
A. Guagliardi, A.G.G. Moliterni, G. Polidori, R. Spagna, J. Appl. Crystallogr. 32
(1999) 115.
[34] C.F. Macrae, I.J. Bruno, J.A. Chisholm, P.R. Edgington, P. McCabe, E. Pidcock,
L. Rodriguez-Monge, R. Taylor, J. van de Streek, P.A. Wood, J. Appl. Crystallogr.
41 (2008) 466e470.
[31] M.C. Burla, R. Caliandro, M. Camalli, B. Carrozzini, G.L. Cascarano, L. De Caro,
C. Giacovazzo, G. Polidori, R. Spagna, J. Appl. Crystallogr. 38 (2005) 381.
[35] L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565.
[36] P. v.d. Sluis, A.L. Spek, Acta Crystallogr. A46 (1990) 194e201.