G.R. Ferreira, L.F.C. de Oliveira / Journal of Molecular Structure 1146 (2017) 50e56
51
the formation of new dyes or support for understanding of supra-
molecular interactions involving the chemistry of these systems
[40,41]. Several metal complexes containing azo dyes ligands pre-
sent aromatic sites with different groups which provide the for-
mation of supramolecular systems presenting weak interactions
through powder diffraction are: (6.71ꢁ; 7.59ꢁ; 10.15ꢁ; 15.51ꢁ;
16.67ꢁ; 23.42ꢁ; 27.61ꢁ).
2.2.3. Synthesis of bis-1-(2,4-xylylazo)-2-naphtholatenickel(II)
(SD2Ni)
such as
p
/
p
, CH/
p
, or even anion/
p
; all such interactions may
To obtain the complex bis-1-(2,4-xylylazo)-2-naphtholatenick-
el(II) was used 0.276 g of 1-(2,4-xylylazo)-2-naphthol solubilized in
30 ml of methanol and 30 ml of dichloromethane, slowly adding
0.106 g of Na2CO3 in magnetic agitation and then 0.237 g of nickel
chloride hexahydrate, after 24 h in reflux at 60 ꢁC a precipitate of
brown color was obtained, solubilized with dichloromethane and
impurities extracted with water several times. The solid was
filtered, dried and purified producing a product with a yield of 78%.
The elemental analysis: Calculated (C32H20NiN6O6): C (59.75%), H
(3.13%), N (13.07%). Found: C (58.07%), H (3.04%), N (12.96%) and the
have a crucial role in auto-assembly and recognition of the solid
state structure. Hydrogen bonding interactions are the most reli-
able and widely used means of enforcing the molecular recognition
of x-ray crystal structures, as it can be seen in literature [42e49].
In spite of the interest in the chemistry of azo dyes being largely
and well explored in the literature on several aspects such as: va-
riety of colors, tautomeric equilibrium between azo and hydrazo
forms, toxicity of these compounds and good sites coordination,
only few complexes between transition metals ions derived from 1-
phenyl-azo-2-naphthol were reported. In this work, we are pre-
senting the synthesis of three new complexes of azo dyes coordi-
nated with metallic cobalt, nickel and copper ion. Techniques such
as Raman, UV/vis, infrared spectroscopy analysis, and X-ray
Diffraction (single and polycrystal) were used in the structural
characterization of these new compounds.
value measurements for 2q
through powder diffraction are: (9.80ꢁ;
11.13ꢁ, 12.27ꢁ; 18.15ꢁ; 21.55ꢁ).
2.3. Physical measurements
2.3.1. Experimental methods
Raman spectra were obtained using a Bruker RFS 100 FT-Raman
instrument equipped with germanium detector refrigerated by
liquid nitrogen, with excitation at 1064 nm from a Nd:YAG laser,
power 30 mW for sample in solid phase, in the range between 1800
and 200 cmꢀ1, and spectral resolution of 4 cmꢀ1, with an average of
1000 scans. All spectra were obtained at least twice to reproduce
position and intensity of all the observed bands. Infrared (IR)
spectra were recorded in an Alpha Bruker FT-IR spectrometer, in the
region 1800e400 cmꢀ1 of the sample supported at KBr pellet, with
4 cmꢀ1 of spectral resolution, and average of 500 scans. The X-ray
powder diffraction (XRP) experiments were obtained using Bruker
D8 Advance diffractometer operating at 40 kV and 30 mA e X-ray
2. Experimental section
2.1. Chemical and reagents
All azo dyes were purchased from Aldrich and the purity of 97%
for Sudan I and 95% for the Sudan II were used without any further
treatment and the solvents used were spectroscopic grade. We
used these metal ions: cobalt chloride hexahydrate, copper chloride
and nickel chloride hexahydrate purchased from Merck.
2.2. Synthesis
2q
/q
. The powder diffraction patterns were obtained with Bregg-
Bretano geometry using K Cu radiation (
¼ 1.5406 Å). The scan-
ning mode was taken from the 2
range of 5e65ꢁ with of 0.02ꢁ. The
Single crystal X-ray data were collected using an Oxford GEMINI A
Ultra diffractometer with CuK
¼ 1.547 Å) at room temperature
2.2.1. Synthesis of tris-1-(phenylazo)-2-naphtholatecobalt(III)
(SD1Co)
a
l
q
The synthesis for obtaining the metal complex tris-1-(phenyl-
azo)-2-naphtholatecobalt(III) Scheme 1, was carried out by the
addition of the 0.248 g of 1-phenyl-azo-2-naphthol dissolved in
methanol, 60 ml and slowly adding 0.106 g of Na2CO3 in magnetic
agitation and then 0.237 g of cobalt chloride hexahydrate dissolved
in deionized water. The reaction occurred under reflux at 60ꢁ C for
about 24 h, affording a black solid which was solubilized with
dichloromethane and impurities extracted from mixing water and
dichloromethane several times. The solid was filtered and washed
with deionized water, and then drying the resulting complex was
weighed 62% yield. The elemental analysis: Calculated
(C48H33CoN6O3): C (72.00%), H (4.15%), N (10.50%). Found: C
m
a (l
(150 K) for tris-1-(pheny-l-azo)-2-naphtholatecobalt(III). Data
collection, reduction and cell refinement were performed by Cry-
sAlis RED, Oxford diffraction Ltd [50], Version 1.171.32.38. The
structures were determined and refined using SHELXL-97 [51]. The
empirical isotropic extinction parameter x was refined according to
the method previously described by Larson [52], and a Multiscan
absorption correction was applied [53]. The structure was drawn by
ORTEP-3 for Windows [54] and Mercury [55] programs. The CCDC
882017 contains the supplementary crystallographic data for tris-1-
(phenylazo)-2-naphtholatecobalt(III). These data can be obtained
Crystallographic Data Centre, 12 Union Road, Cambridge CB2 IEZ,
(69.49%), H (4.34%), N (9.76%) and the value measurements for 2
q
through powder diffraction are: (7.62ꢁ; 9.84ꢁ; 10.54ꢁ; 14.18ꢁ;
15.29ꢁ).
2.2.2. Synthesis of bis-1-(phenyl-azo)-2-naphtholatecopper(II)
(SD1Cu)
2.3.2. Calculations
Similarly, the synthesis was carried out to obtain the complex
bis-1-(pheny-l-azo)-2-naphtholatecopper(II) used to be 0.248 g of
1-phenyl-azo-2-naphthol solubilized in 30 ml of methanol and
30 ml of dichloromethane, slowly adding 0.106 g of Na2CO3 in
magnetic agitation and then 0.134 g of copper chloride obtained
after 24 h in reflux at 60 ꢁC a precipitate of red color which was
solubilized with dichloromethane and impurities extracted with
water several times. The solid was filtered, purified and dried
producing a product with 67% yield. The elemental analysis:
Calculated (C32H22CuN4O2): C (61.67%), H (3.73%), N (8.72%). Found:
The structures of the metal complexes were fully optimized in
the gas phase at B3LYP [56,57] level using the 6-311þþG(d,p) [58]
triple-zeta basis-set with the inclusion of diffuse and polarization
functions at heavy and hydrogen atoms (hereafter abbreviated as
B3LYP/6-311þþG(d,p)) (the optimized structures are shown in
Fig. S1 as Supplementary Materials). All of the geometries were
considered as neutral species with the multiplicities set to singlet
for the nickel complex and duplet for the copper complex. The
infrared (IR) and Raman intensities were also calculated and the
band spectra simulated by fitting a Lorentzian type function. All
calculations were carried out with Gaussian 09 [59] program as
C (59.67%), H (3.77%), N (8.51%) and the value measurements for 2
q
Ferreira, Gilson Rodrigues
