Three new mononuclear group 12 complexes with benzimidazole

Article abstract of DOI:10.1080/00958972.2014.914179

Three iso-structural Zn(II), Cd(II), and Hg(II) complexes with 1-benzyl-2-phenyl-1H-benzimidazole (BPB), ZnBPB, CdBPB, and HgBPB, respectively, were synthesized by reaction of the ligand with the corresponding metal chlorides in methanolic solutions. The

Full text of DOI:10.1080/00958972.2014.914179

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Three new mononuclear group 12
complexes with benzimidazole
a
b
Thaeny C. Amaral , Gustavo S.G. De Carvalho , Adilson D.
b
c
d
Da Silva , Pedro P. Corbi , Norberto Masciocchi , Eduardo E.
e
a
Castellano & Alexandre Cuin
a
LQBin, Laboratório de Química BioInorgânica, Departamento de
Química, Instituto de Ciências Exatas, Juiz de Fora, Brazil
b
Departamento de Química, Instituto de Ciências Exatas, Juiz de
Fora, Brazil
c
Instituto de Química, Universidade Estadual de Campinas-
UNICAMP, Campinas, Brazil
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d
Dipartimento di Scienza e Alta Tecnologia, Università degli Studi
dell’Insubria, Como, Italy
e
Instituto de Física, Universidade de São Paulo-USP, São Carlos,
Brazil
Accepted author version posted online: 10 Apr 2014.Published
online: 09 May 2014.
To cite this article: Thaeny C. Amaral, Gustavo S.G. De Carvalho, Adilson D. Da Silva, Pedro P.
Corbi, Norberto Masciocchi, Eduardo E. Castellano & Alexandre Cuin (2014) Three new mononuclear
group 12 complexes with benzimidazole, Journal of Coordination Chemistry, 67:8, 1380-1391, DOI:
10.1080/00958972.2014.914179
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Journal of Coordination Chemistry, 2014
Vol. 67, No. 8, 1380–1391, http://dx.doi.org/10.1080/00958972.2014.914179
Three new mononuclear group 12 complexes with
benzimidazole
THAENY C. AMARAL†, GUSTAVO S.G. DE CARVALHO‡, ADILSON D. DA SILVA‡,
PEDRO P. CORBI§, NORBERTO MASCIOCCHI¶, EDUARDO E. CASTELLANO‖ and
ALEXANDRE CUIN*†
†
LQBin, Laboratório de Química BioInorgânica, Departamento de Química, Instituto de Ciências
Exatas, Juiz de Fora, Brazil
‡
Departamento de Química, Instituto de Ciências Exatas, Juiz de Fora, Brazil
Instituto de Química, Universidade Estadual de Campinas-UNICAMP, Campinas, Brazil
Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell’Insubria, Como, Italy
Instituto de Física, Universidade de São Paulo-USP, São Carlos, Brazil
§
¶
‖
(Received 12 November 2013; accepted 24 March 2014)
Three iso-structural Zn(II), Cd(II), and Hg(II) complexes with 1-benzyl-2-phenyl-1H-benzimidazole
BPB), ZnBPB, CdBPB, and HgBPB, respectively, were synthesized by reaction of the ligand with
the corresponding metal chlorides in methanolic solutions. The complexes [MCl (BPB) ], where
(
2
2
13
1
1
15
M = Zn(II), Cd(II), or Hg(II), were characterized by elemental analysis, C, H, and [ H– N]
heteronuclear multiple bond coherence NMR measurements, and Raman spectroscopy. The structures
of the cadmium and mercury complexes were solved by single-crystal X-ray diffraction, while the
structure of the zinc complex was determined by X-ray powder diffraction. The three compounds
crystallize in the triclinic system in P-1 space group with the metal ions lying in a distorted tetrahedral
environment. The zinc complex shows high luminescence in the solid state at room temperature.
Keywords: Zinc; Cadmium; Mercury; Powder diffraction; 1-Benzyl-2-phenyl-1H-benzimidazole
*
Corresponding author. Email: alexandre.cuin@ufjf.edu.br
2014 Taylor & Francis
©

Group 12 benzimidazole complexes
1381
1. Introduction
Benzimidazoles are a class of organic compounds which possess extensive applications,
especially in medicinal chemistry and a number of compounds containing a benzimidazole
have been prepared and described with anti-inflammatory [1], anticancer [2], antimicrobial
[
3–5], antifungal [6], antiparasitic [7, 8], and antiviral activities [9]. Benzimidazole-based
metal complexes with luminescent properties [10–13] are also known. In coordination
chemistry, benzimidazoles are excellent N-donor ligands with formation of various metal
complexes that exhibit different coordination numbers and geometries [14–16]. In this
article, we report the synthesis, analytical, spectroscopic, and luminescence data of group
1
2 metal complexes with 1-benzyl-2-phenyl-1-benzimidazole (BPB, chart 1). Crystal struc-
tures of three complexes obtained by single crystal and less conventional powder diffraction
methods are reported.
2
2
. Experimental
.1. Physical techniques and materials
All reagents and solvents for syntheses and spectroscopic studies were purchased from
Sigma-Aldrich and used without purification. All spectra were recorded on Bruker spectrom-
1
3
eters. The C NMR spectrum of BFB was recorded on an Avance II instrument operating at
1
3
6
2.5 MHz while HgBFB and CdBFB C NMR spectra were recorded on an Avance 600
1
3
instrument operating at 150 MHz, and finally ZnBFB C NMR spectrum was obtained on
an Avance 500 instrument operating at 125 MHz. The C NMR chemical shifts were refer-
enced to an internal standard (tetramethylsilane – TMS). The H and N NMR spectra were
obtained on an Avance III 400 MHz (9.395T) instrument, specifically the N NMR spectra
1
3
1
15
1
5
Chart 1. Sketch of BPB molecule. Carbon atoms are numbered and hydrogens are omitted for clarity. The torsion
angles refined in the powder diffraction analysis of the ZnBPB complex are indicated as τ1, τ2, and τ3.

1
382
T.C. Amaral et al.
1
15
were acquired indirectly [ H– N] by heteronuclear multiple bond coherence technique
1
5
1
15
(
HMBC) using a 5 mm probe and a temperature of 298 K. The N NMR spectra ( H– N
HMBC) were obtained at 40.54 MHz. Samples were prepared in deuterated chloroform solu-
tions (CDCl ) and the chemical shifts are given relative to TMS. The Raman spectra were
3
3
+
recorded on a Bruker spectrophotometer model RFS 100 equipped with Nd /YAG laser at
064 nm and with 1.0 cm resolution. The excitation and emission spectra of complexes
−
1
1
were obtained using a fluorescence master system PTI spectrofluorometer.
2
.2. Syntheses
BPB: benzaldehyde (19.62 mM, 2.0 mL) was added to an ethanolic solution containing 10 mL
−1
of 1,2-phenylenediamine (1.06 g, 9.81 mM). After 10 min, 0.50 mL of HCl (0.10 M L ) was
added and the final solution was stirred for 3 h at room temperature. A polycrystalline com-
pound was obtained and collected by filtration, washed with cold ethanol, and dried in a desic-
cator with silica. The BFB can also be obtained using basic solution [17] or microwave
radiation [18]. A feasible mechanism from Schiff bases to benzimidazoles was recently
described [18, 19].
Complexes: the dichlorobis(1-benzyl-2-phenyl-1H-benzimidazole)cadmium(II) and
dichlorobis(1-benzyl-2-phenyl-1H-benzimidazole)mercury(II) complexes (named CdBPB
and HgBPB) were obtained by reaction of 1.0 mM of MCl (M = Cd, Hg) with 2.0 mM of
2
BPB in methanolic solution under stirring at 50 °C for 2 h. The solid compounds obtained
were collected by filtration. Crystals suitable for single-crystal X-ray analyses were obtained
from the supernatants which were left to stand for a few days. The dichlorobis(1-benzyl-2-
phenyl-1H-benzimidazole)zinc(II) complex (ZnBPB) was prepared in the same way as
CdBPB and HgBPB. However, only a polycrystalline powder was obtained. The solid was
collected by filtration and dried in a desiccator with silica before characterization.
2.3. Single X-ray data collection and structure determination
Single crystals of CdBPB and HgBPB were measured on an Enraf-Nonius Kappa-CCD dif-
fractometer with graphite monochromated MoKα (λ = 0.71073 Å) radiation. Data were col-
lected at room temperature up to 52° in 2θ and final unit cell parameters were based on all
reflections. Data collections were made using the COLLECT program [20]. Integration and
scaling of the reflections were performed with the HKL Denzo–Scalepack system of pro-
grams [21]. Absorption corrections were carried out using the RefDelF procedure [22]. The
structure was solved by direct methods with SHELXS-97 [23]. The model was refined by
2
full-matrix least squares on F using SHELXL-97 [24]. All hydrogens were stereochemically
positioned and refined with the riding model.
2
.4. Structural analysis of ZnBPB by X-ray powder diffraction data
The polycrystalline ZnBPB complex was gently ground in an agate mortar. The powder
was deposited in a sample holder equipped with a silicon zero-background plate. The dif-
fraction data were collected by overnight scans in the 2θ range of 3°–105° with steps of
0
.02° using a Bruker AXS D8 Advance diffractometer equipped with Ni-filtered CuKα radi-
ation (λ = 1.5418 Å) and Lynxeye linear position-sensitive detector. The following optics
were set up: primary beam Soller slits as 2.3°, fixed divergence slit as 0.5°, and receiving

Group 12 benzimidazole complexes
1383
slit as 8 mm. The generator was set at 40 kV and 40 mA. Standard peak search, followed by
indexing through the single-value decomposition approach implemented in TOPAS [25]
allowed detection of the approximate triclinic unit cell parameters. Density considerations
suggested Z = 2 and the space group P-1 was chosen. Structure solution was performed by
the simulated annealing technique implemented in TOPAS. The rigid body for BPB
described as cartesian coordinates was employed where translations, rotations, and torsion
angles (see chart 1) were left free. Zinc and chloride ions were freely floating. Final refine-
ments were carried out by the Rietveld method maintaining the rigid body introduced at the
solution stage. The background was modeled by a Chebyshev polynomial function and
peak width anisotropy was described by a spherical harmonics model. An isotropic thermal
parameter was assigned to the metal (B ) and refined; lighter atoms were given a
M
2
Biso = B + 2.0 Å thermal parameter. The final Rietveld refinement plot is supplied as
M
figure 1.
3
3
. Results and discussion
.1. Elemental analyses
Elemental analyses and complementary analytical data for free BPB and its Zn(II), Cd(II),
and Hg(II) complexes are presented in table 1. The experimental data match with the molar
composition [MCl (BPB) ].
2
2
3
.2. Spectroscopic studies
BPB and its Zn(II), Cd(II), and Hg(II) complexes show quite similar Raman spectra and all
spectra are reported in Supplementary material. The most important bands and the
assignments are described in table 2. The combination band between νC=N and the
Figure 1. Final Rietveld refinement plot for ZnBPB with difference plot and peak markers at the bottom. The
insert shows the high angle region at a magnified scale (5x).

1
384
T.C. Amaral et al.
Table 1. Analytical data for BPB and its Zn(II), Cd(II), and Hg(II) complexes.
Analytical data found (Calcd), %
Yield
(%)
MP
(°C)
−
1
Compound
BPB [17]
Formula (MW, gM
)
Color
C
H
N
C
20
H
16
N
2
(284.3)
90
77
70
84
Yellow
118
283
230
201
84.4
84.5)
67.9
(68.1)
64.0
(63.9)
57.1
(57.2)
5.55
(5.67)
4.57
(4.57)
4.59
(4.29)
3.82
(3.84)
9.89
(9.85)
7.90
(7.95)
7.40
(7.45)
6.67
(6.67)
(
ZnBPB
CdBPB
HgBPB
[Zn(C20
705.03)
[Cd(C20
752.03)
[Hg(C20
840.20)
H
16
N
2
)
2
Cl
Cl
Cl
2
]
Colorless
Colorless
Colorless
(
H
16
N
2
)
2
2
]
(
H
16
N
2
)
2
2
]
(
Table 2. Raman resonances of BPB and its group 12 metal complexes.
BPB
ZnBPB
CdBPB
HgBPB
Assignment
1
1
1
1
603s
1606s
1519s
1455s
1002s
1607s
1523s
1455s
1004s
164w
1606s
1519s
1454s
1002s
159w
νC=N + νCCarom
νC=N + νCCarom
νCCarom
νC–N
νM–Cl/νM–N
515s
442s
004s
1
65w
Note: s = strong, w = weak.
−
1
aromatic carbon bonds νCCarom is observed at 1603 cm for BPB [26]. The same
−1
combined band is observed at 1606–1607 cm for Zn(II), Cd(II), and Hg(II) complexes
showing a small and well-known [27] displacement when BPB is coordinated to metal ions.
−
1
−1
Beyond 250 cm , free BPB shows two weak bands at 210 and 188 cm . The Raman spec-
−
1
tra of MCl (M=Zn, Cd, and Hg) were also measured: for ZnCl , bands at 130 and 91 cm
are observed, whereas CdCl and HgCl show resonances at 162 and 121 cm . Weak
bands are observed at 213, 198, and 165 cm for ZnBPB and 215, 196, and 164 cm for
CdBPB. For HgBPB, it is also possible to observe weak bands at 213 and 192 cm while
stronger bands appear at 252 and 159 cm . Following previous reports, we assign the reso-
nances of the M–Cl or M–N bond stretch where M = Zn(II), Cd(II), and Hg(II) at 165 cm ,
64 cm [28], and 159 cm [29], respectively.
The observed chemical shifts and the respective assignments of C and H data for BPB
are described in table 3. The C, H, and N NMR spectra of BPB and the complexes are
2
2
−1
2
2
−
1
−1
−
1
−
1
−
1
−
1
−1
1
1
3
1
1
3
1
15
1
13
very similar and only NMR data for BFB are shown in table 3. However, the H, C, and
H– N] spectra of BFB and its Zn(II), Cd(II), and Hg(II) complexes are available as Sup-
1
15
[
plementary material. The carbon numbering scheme in chart 1 is used to simplify the NMR
assignments and discussion. The C14 (the only –CH – present in BPB) appears at 47.9 ppm
2
1
3
in all C NMR spectra. The chemical shift of the carbon of –N=C–(C1) is observed at
53.8 ppm for BPB and for the three complexes. There are a few peaks in the 110–131 ppm
1
range which are attributed to carbons present in the three phenyl rings (C3–C7, C9–C12,
and C16–C20) and four other peaks at 136.3, 136.4, 137.4, and 143.1 ppm which are
1
related to the C15, C2, C13, and C8, respectively. In the same way, peaks in all H spectra
1
5
1
15
are similar. The N chemical shift for BPB was indirectly detected by [ H– N] HMBC
experiments. Only one signal assigned to nitrogen bonded to C14 was found at 148 ppm
coupling with hydrogens of –CH – (two-bond correlation). For Zn(II), Cd(II), and Hg(II)
2
complexes, the same resonance falls at 149 ppm showing a minimal shift. Multiple-bond

Group 12 benzimidazole complexes
C and H NMR data of free BPB.
1385
13
1
Table 3.
13
C NMR data
–
C14
CH –,
2
C3,C4,C5,C6,C7; C9,C10,C11,C12;
C16,C17,C18,C19,C20
111.5; 119.7; 122.7; 123.1; 126.5;
N=C,
C1
C15, C2, C13, C8
136.3; 137.3; 143.1
47.9
1
53.7
1
27.9; 129.2; 129.5; 130.6
1
H NMR data
–
CH
2
–
Aromatic hydrogen atoms
6.99(2)d; 7.25(5)m; 7.46 and 7.53(4)m; 7.73(3)m
5.58(2)s
Note: s, singlet; d, doublet; m, multiplet. The numbers in parentheses refer to the number of protons as derived from integration of
the signals.
correlation of this nitrogen with hydrogen bonded to C12 (aromatic) was not observed.
Also, possible interactions of the N of –N=C– with hydrogens of phenyl rings which
required three-bond correlation were not observed.
3
.3. Crystal structure studies
The structures of the three molecular compounds have been derived from single-crystal
CdBPB and HgBPB) or powder (ZnBPB) X-ray diffraction analyses (crystallographic data
(
are supplied in table 4). The latter method for specimens of moderate complexity can afford
interesting crystallochemical information (stoichiometry, crystal packing, and conformation)
at the expenses of relatively high idealization. In this case, as reported in the Experimental
section, extensive use of (partially flexible) rigid bodies does not allow discussion of rele-
vant intramolecular features but only a cross-comparison of ZnBPB with the Cd and Hg
analogs. Accordingly, the most relevant bond distances, angles, and torsions of the ZnBPB,
CdBPB, and HgBPB complexes are listed in tables 5 and 6 to a different number of
significant digits (see esd’s – estimated standard deviations).
Crystals of the three species are triclinic, space group P-1, and contain independent mole-
cules packed by weak van der Waals interactions, since neither specifically polar moieties
nor acidic hydrogens can be found on their periphery. However, a few weak H⋯Cl and
H⋯Caromatic intermolecular interactions can be distinctly evidenced in all cases.
The three MBPB structures (M = Zn, Cd, Hg) can be considered isomorphous, although
lattice constants and particularly the interaxial angles appear significantly different to a level
that the originally collected powder diffraction trace of ZnBPB could by no means be asso-
ciated with those computed from the already available single-crystal structures of CdBPB
and HgBPB.
The molecular structures of CdBPB and HgBPB complexes are shown as ORTEP 3 [30]
plots in figure 2((a) and (b), respectively) and are nearly undistinguishable at the drawn res-
olution. At variance, the molecule of ZnBPB drawn by SCHAKAL [31] appears in a nearly
iso-oriented way in panel c of figure 2. In figure 3, the overall crystal packing of ZnBPB is
presented which to some extent also represents those of CdBPB and HgBPB.
A number of torsion angles defining the ligand conformations for free BPB, Zn(II), Cd
(II), and Hg(II) complexes and similar compounds [17, 32, 33] are reported in table 6. The
molecular structures of similar Cd(II) and Hg(II) complexes were very recently reported by
Manjunatha et al. [32] soon after the crystal structure of free BPB appeared, in 2009 [17].
As expected, slight changes in the conformation of the ligands were observed.

1
386
T.C. Amaral et al.
Table 4. Crystallographic data of ZnBPB, CdBPB, and HgBPB complexes.
ZnBPB
CdBPB
HgBPB
966371
CCDC number
Empirical formula
Formula weight
T (K)
Wavelength (Å)
Crystal system
Space group
Cell parameters
a (Å)
b (Å)
c (Å)
α (°)
β (°)
966369
966370
C
40
H
32Cl
2
N
4
Zn
C
40
H
32CdCl
2
N
4
40 2 4
C H32Cl HgN
704.97
296(2)
1.5418
Triclinic
P-1
752.00
296(2)
0.71073
Triclinic
P-1
840.19
296(2)
0.71073
Triclinic
P-1
10.9295(6)
10.2607(6)
18.725(1)
87.321(6)
64.346(4)
65.084(4)
2
1693.0(2)
1.383
2.73
10.6138(3)
10.8766(4)
17.5400(6)
79.851(2)
74.691(2)
62.491(2)
2
1728.71(1)
1.445
0.821
10.6092(3)
10.8694(4)
17.5869(6)
80.050(2)
74.690(2)
62.401(2)
2
1730.47(1)
1.612
4.636
γ (°)
Z
3
Volume (Å )
D
μ (mm
3
Calcd (g/cm )
−
1
)
F (0 0 0)
728
764
828
Number of parameters
R, wR
Δρmin, Δρmax (eA )
61
424
424
a
0.028, 0.081
–
10.68
0.0772, 0.194
−0.67, 3.00
1.011
0.0557, 0.131
−1.21, 1.80
1.069
3
a
Goodness-on-fit (GOF)
a
Profile values for powder diffraction study.
Table 5. Chemically relevant bond distances (Å) and angles (°) for ZnBPB, CdBPB, and
HgBPB.
ZnBPB
CdBPB
HgBPB
M–Cl
M–N
Cl–M–Cl
N–M–N
2.269(1)/2.320(1)
2.041(9)/2.050(8)
115.81(5)
2.437(2)/2.449(2)
2.240(4)/2.289(4)
114.77(7)
2.450(2)/2.472(2)
2.252(4)/2.266(4)
116.18(7)
120.02(4)
119.13(14)
119.03(16)
Table 6. Torsion angles of BPB and its group 12 complexes and related compounds.
τ
1
τ
2
τ
3
τ
4
BPB [17]
ZnBPB
+31.28
+44.93
−101.79
−111.60
−100.78
−101.61
−103.70
−103.07
−102.42
−113.65
−132.38
−133.21
+12.91
+34.30
+19.67
+24.88
+25.87
+25.64
+26.28
+17.40
+49.12
+49.69
–
25.20
33.43
+28.79
+31.35
+27.15
+32.27
–
+
42.86
+45.75
44.34
+45.09
46.21
CdBPB
HgBPB
+
+
mbmpi
Cdmbmpi [32]
Hgmbmpi [32]
+35.68
+53.14
+53.47
+40.85
+41.57
Note: τ
4
was defined as torsion angle formed by N–M–N–C, where M is the metal ion and C is
, τ , and τ were defined according to chart 1.
the carbon atom of –N = C–N– group and τ
1
2
3

Group 12 benzimidazole complexes
1387
Figure 2. ORTEP views of CdBPB ((a) with atom labeling) and HgBPB (b) molecules. Hydrogens are
not included in the drawings. (c) SCHAKAL plot for the ZnBPB complex, iso-oriented with (a) and (b). Zinc
ion is in pink while chlorine and nitrogens are green and blue, respectively (see http://dx.doi.org/10.1080/
00958972.2014.914179 for color version).

1
388
T.C. Amaral et al.
Figure 3. The crystal packing of ZnBPB viewed down (1 0 0). Horizontal axis is c.
Figure 4. Solid-state emission of three complexes at room temperature using wavelength of excitation at 333 nm.
3.4. Photoluminescence behavior
Preliminary solid-state photoluminescence properties of the three complexes were studied at
room temperature (298 K). The emission spectra of complexes were obtained by exciting
the samples using λexc 333, 355, and 368 nm. ZnBPB is the most fluorescent complex while
CdBPB and HgBPB are progressively less luminescent. In particular, when λexc = 333 nm
was used (see figure 4), ZnBPB has a maximum emission at 396 nm with a shoulder

Group 12 benzimidazole complexes
1389
Figure 5. Emission spectra of the three complexes. Excitation has been observed between 200 and 400 nm with
the fluorescence detector fixed at 425 nm.
centered near 425 nm; the same behavior was found for CdBPB but the shoulder near
425 nm becomes less perceptible. The photoluminescence behavior of BFB complexes is
similar to luminescence properties of related compounds [34, 35].
Interestingly, when λexc = 355 or 368 nm were used, ZnBPB shows only one strong emis-
sion peak (at 425 nm) while the overall emission of HgBPB and CdBPB are significantly
quenched. All observed peaks can be attributed to π→π* intra-ligand or ligand-to-metal
charge transfer mechanisms [36]. The excitation spectra of the three compounds obtained
from 200 to 400 nm with fluorescence detection fixed at 425 nm are quite different
(
figure 5). The ZnBPB complex shows high fluorescence when considering λexc = 333 and
3
68 nm, whereas CdBPB only manifests the emission at λexc = 333 nm.
4
. Conclusion
Three mononuclear [MCl (BPB) ] complexes (M = Zn(II), Cd(II), and Hg(II)) were
2
2
obtained and characterized by analytical and spectroscopic measurements. Their structures
determined by X-ray crystallography show that the ZnBPB, CdBPB, and HgBPB com-
plexes are iso-structural with the metal ions lying in a distorted tetrahedral environment.
The structure of the zinc complex was determined and refined from laboratory powder dif-
fraction data only and as expected the quality of the structural model determined therefrom
is much lower than from conventional single-crystal diffraction analysis. In the absence of
single crystals of suitable size and quality, powder diffraction study discloses otherwise
inaccessible structural information. All three complexes are luminescent; the higher quan-
tum yields of ZnBPB make it a potentially useful photoactive material.
Supplementary material
Crystal data, fractional atomic coordinates, and displacement parameters of structures
described in this article are supplied in standard CIFs deposited in the Cambridge

1
390
T.C. Amaral et al.
Crystallographic Data Center (966369, 966370, and 96671). The data can be obtained free
of charge at http://www.ccdc.cam.ac.uk/conts/retrieving.html [or from Cambridge Crystallo-
graphic Data Center (CCDC), 12 Union Road, Cambridge CB2 1EZ, UK; Fax: +44 (0)
1
223-336033; E-mail: deposit@ccdc.cam.ac.uk]. Also, complete set of Raman spectra and
1
13
1
15
H, C, and [ H– N] NMR spectra of BFB and its complexes are available as Supplemen-
tary material.
Funding
This work was supported by grants from FAPEMIG – Fundação de Amparo à Pesquisa do Estado de Minas Gerais
(
CEX-APQ-00256/11), CNPq – Conselho Nacional de Desenvolvimento Científico e Tecnológico (240094/2012-3
fellowship for Alexandre Cuin) and by FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo – Grant
2012/08230-2). The courtesy of Dr Angelo Maspero (University of Insubria) and Luca Nardo (University of Mi-
#
lano Bicocca) is heartily acknowledged.
Supplemental data
Supplemental data for this article can be accessed here http://dx.doi.org/10.1080/00958972.
2014.914179
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