Preparation and characterization of copper sulfide nanoparticles from symmetrical [(Bu) 2NC(S)NC(O)C 6H 3(3,5-NO 2) 2] 2Cu(II) and [(Bu) 2NC(S)NC(O)C 6H 4(4-NO 2)] 2Cu(II) complexes by thermolysis

Article abstract of DOI:10.1080/00958972.2014.950958

Trigonal copper sulfide nanoparticles were synthesized from symmetrical [(Bu)2NC(S)NC(O)C6H3(3,5-NO2)2]2Cu(II) and [(Bu)2NC(S)NC(O)C6H4(4-NO2)]2Cu(II) complexes by thermolysis in the presence of surfactant oleylamine. The symmetrical copper complexes were

Full text of DOI:10.1080/00958972.2014.950958

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Preparation and characterization
of copper sulfide nanoparticles
from symmetrical
[(Bu)2NC(S)NC(O)C6H3(3,5-NO2)2]2Cu(II)
and [(Bu)2NC(S)NC(O)C6H4(4-
NO2)]2Cu(II) complexes by thermolysis
Sohail Saeedab & Rizwan Hussainb
a Department of Chemistry, Research Complex, Allama Iqbal Open
University, Islamabad, Pakistan
b National Engineering & Scientific Commission, Islamabad,
Pakistan
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Accepted author version posted online: 07 Aug 2014.Published
online: 27 Aug 2014.
To cite this article: Sohail Saeed & Rizwan Hussain (2014) Preparation and characterization
of copper sulfide nanoparticles from symmetrical [(Bu)2NC(S)NC(O)C6H3(3,5-NO2)2]2Cu(II) and
[(Bu)2NC(S)NC(O)C6H4(4-NO2)]2Cu(II) complexes by thermolysis, Journal of Coordination Chemistry,
67:17, 2942-2953, DOI: 10.1080/00958972.2014.950958
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Journal of Coordination Chemistry, 2014
Vol. 67, No. 17, 2942–2953, http://dx.doi.org/10.1080/00958972.2014.950958
Preparation and characterization of copper sulfide
nanoparticles from symmetrical [(Bu)2NC(S)NC(O)C6H3(3,5-
NO2)2]2Cu(II) and [(Bu)2NC(S)NC(O)C6H4(4-NO2)]2Cu(II)
complexes by thermolysis
SOHAIL SAEED†‡* and RIZWAN HUSSAIN‡
†Department of Chemistry, Research Complex, Allama Iqbal Open University, Islamabad, Pakistan
‡National Engineering & Scientific Commission, Islamabad, Pakistan
(Received 12 July 2013; accepted 27 June 2014)
Trigonal copper sulfide nanoparticles were synthesized from symmetrical [(Bu)2NC(S)NC(O)
C6H3(3,5-NO2)2]2Cu(II) and [(Bu)2NC(S)NC(O)C6H4(4-NO2)]2Cu(II) complexes by thermolysis in
the presence of surfactant oleylamine. The symmetrical copper complexes were synthesized by reac-
tion of copper(II) acetate with N-(3,5-dinitrobenzoyl)-N′,N′-dibutylthiourea and N-(4-nitrobenzoyl)-N′,
N′-dibutylthiourea. The symmetrical copper complexes were characterized by FT-IR spectroscopy,
elemental analysis, and mass spectrometry (MS-APCI). The single-crystal X-ray structure of
[(Bu)2NC(S)NC(O)C6H4(4-NO2)]2Cu(II) has been determined from single-crystal X-ray diffraction
data. These metal complexes have been used as single source precursors for the preparation of
copper sulfide nanoparticles. The deposited copper sulfide nanoparticles were characterized by X-ray
powder diffraction and transmission electron microscopy.
Keywords: Symmetrical copper complexes; Copper sulfide nanoparticles; p-XRD; TEM
1. Introduction
“Small-particle” research has become quite popular in chemistry and physics. The “small-
particles,” now being called nanostructured materials, are interesting both for scientific rea-
sons and practical applications [1, 2]. Nanostructured semiconductor materials of various
shapes and sizes (triangles, rods, cubes, arrows, and tetrapods) [3, 4] have been synthesized
*Corresponding author. Email: sohail262001@yahoo.com
© 2014 Taylor & Francis

Copper sulfide nanoparticles
2943
and extensively studied due to their properties that are different from those observed in their
spherical counterparts [5–7]. Moreover, nanoparticles having mesoporous nanostructures
have higher surface-to-volume ratio, higher chemical activity, and better stability compared
with the same-sized nanoparticles.
The use of organometallic precursor compounds for controlled synthesis of semiconduct-
ing quantum dots was pioneered by Bawendi and co-workers; however, the noxious and
hazardous nature of the starting compounds necessitates the need for safer synthetic routes
[8]. To this end the use of single-source precursors has attracted significant attention and a
variety of precursor complexes have been reported [9, 10].
Metal complexes of thiourea are neutral compounds. These chelating agents have been
remarkable ones for analytical chemistry, especially for trace analysis of metals in complex
matrices. The coordination chemistry and potential applications of such ligands have only
been explored to a small extent in the last few decades. With the presence of O, N, N′, and
S donors, substituted acylthiourea ligands exhibit various coordination modes: (scheme 1):
(a) O and S bonded to M (monobasic bidentate) [11], (b) only S bonded to M (neutral
monodentate) [12], (c) O and N bonded to M (neutral bidentate) [13], and (d) O and S
bonded to M and N is bonded to M′ (monobasic bridging ligand) [14]. It has been shown
that substituted acylthiourea ligands, which do not form an intramolecular hydrogen bond,
tend to coordinate predominately in bidentate (S, O) fashion to transition metal ions through
the sulfur and acyl oxygen [14]. Examples for this type of coordination are mononuclear
complexes of the type [ML2], where M = Ni(II), Cu(II), Co(II), Zn(II), Cd(II), Pt(II), and
Pd(II) and L = substituted acylthiourea derivatives [15]. Coordination solely through sulfur
is rare and occurs only for complexes with Au(I) [16], Ag(I) [17], Hg(II) [18], and Cu(I)
[19]. It has been suggested that intramolecular hydrogen bonding exists between the thio-
urea N–H moiety (where R/R′ = H) and the amidic O-donor to form a six-membered ring,
with the consequence that the ligands coordinate monodentate to metal centers through sul-
fur [14]. Various structures of CuS have been synthesized. For example, copper sulfide hol-
low spheres by self-assembly coupled with H2S bubble templating [21], CuS hollow [22],
wires [23], rods [24], tubes [25], platelets [26, 27] flower-like structures [19, 20], and nano-
ribbons [28]. There are various methods for preparation of copper sulfide in nanoscale such
as hydrothermal/solvothermal [28], template-assisted growth [22], microwave irradiation,
and grinding [29].
O
S
O
S
O
S
O
N
N
NH
N
NH
M
NH
N
M
M
M
S
R'
R'
M'
R'
R'
N
R
R
R
R
(a)
(b)
(d)
(c)
Scheme 1. Four possible coordination modes of the N-dialkyl/aryl-N′-acylthiourea ligands in various metal
complexes.

2944
S. Saeed and R. Hussain
Our team has focused on synthesis, characterization, crystal structures, biological
activities, and material applications of new thiourea derivatives and their metal complexes
[30–37]. As part of our long-standing interest in the coordination chemistry of N,N-dialkyl-N′-acyl
(aroyl)thioureas, we here explore the synthesis of CuS nanoparticles from single-source
precursors bis[N-(3,5-dinitrobenzoyl)-N′,N′-dibutylthiourea]copper(II), and bis[N-(4-nitro-
benzoyl)-N′,N′-dibutyl thiourea]copper(II) derived from HL1 and HL2. These complexes have
not been used as single-source precursors for preparation of copper sulfide nanoparticles.
2. Experimental
2.1. Materials and physical measurements
Analytical grade 4-nitrobenzoyl chloride (≥98.0%), di-n-butylamine (99%), sodium thiocya-
nate (99%), copper(II) nitrate trihydrate (99.5%), tetrabutylammonium bromide (TBAB)
(≥98%), oleylamine, approx. C18-content 80–90%, and 3,5-dinitrobenzoyl chloride
(≥98.0%) were purchased from Sigma–Aldrich. Elemental analysis was performed by the
University of Manchester micro-analytical laboratory. Infrared spectra were recorded on a
Specac single reflectance Attenuated Total Reflectance instrument (4000–400 cm−1, resolu-
tion 4 cm−1). Atmospheric pressure chemical ionization mass spectrometry (MS-APCI) of
copper complexes was recorded on a Micromass Platform II instrument. Metal analysis of the
complexes was carried out by Thermo iCap 6300 Inductively Coupled Plasma Optical Emis-
sion Spectroscopy. Melting points were recorded on the Barloworld SMP10 Melting Point
Apparatus. X-ray powder diffraction (p-XRD) studies were performed on an Xpert diffrac-
tometer using Cu Kα radiation. The samples were mounted flat and scanned between 20 and
65° with a step size of 0.05 with various count rates. The diffraction patterns were then com-
pared to the documented patterns in the International Center Diffraction Data (ICDD) index.
Transmission electron microscopy (TEM) samples were prepared by evaporating a drop of a
dilute suspension of the sample in n-hexane on carbon-coated copper grid. The excess solvent
was allowed to dry completely at room temperature. TEM images were collected on a Philips
CM200 transmission electron microscope using an accelerating voltage 200 kV.
2.2. X-ray structure determination
Single-crystal X-ray diffraction data for [Cu(L2)2] were collected using graphite-monochro-
mated Mo Kα radiation (λ = 0.71073 Å) on a Bruker SMART 1000 CCD diffractometer.
Crystallographic data were collected using graphite-monochromated Mo Kα radiation and
integrated and corrected for absorption using the CrysAlisRed (Oxford Diffraction, 2010
software package) [38]. The structures were solved using direct methods and refined using
least squares on F2 [39]. All non-hydrogen atoms were refined anisotropically. Hydrogens
were included in calculated positions, assigned isotropic thermal parameters, and allowed to
ride on their parent carbon.
2.3. Synthesis of copper sulfide nanoparticles
Copper sulfide nanoparticles were prepared by pyrolyzing the copper complexes as precur-
sors in oleylamine by thermolysis. In a typical reaction, 15 mL of oleylamine refluxed

Copper sulfide nanoparticles
2945
under vacuum at 90 °C for 45 min, and then it was purged by nitrogen gas for 30 min, at
the same temperature. Then 0.3 g of precursor was added into the hot oleylamine and the
reaction temperature was slowly increased to a desired point (170 and 230 °C). The temper-
ature was maintained for one hour and the mixture was allowed to cool at room tempera-
ture. Addition of 30 mL methanol produced a black precipitate which was separated by
centrifugation. The black residue was washed twice by methanol and re-dispersed in toluene
or hexane for further characterizations.
2.4. Synthesis of the ligands and copper complexes
2.4.1. General method for the preparation of acylthiourea ligands. A solution of nitro-
substituted benzoyl chloride (0.01 M) in anhydrous acetone (80 mL) and 0.3% of TBAB in
acetone was added dropwise to a suspension of sodium thiocyanate in acetone (50 mL) and
the reaction mixture was refluxed for 45 min. After cooling to room temperature, a solution
of di-n-butylamine (0.01 M) in acetone (25 mL) was added and the resulting mixture
refluxed for 2 h. The reaction mixture was poured into five times its volume of cold water,
whereupon the acylthiourea precipitated. The solid product was washed with water and
purified by re-crystallization from an ethanol–dichloromethane mixture (1 : 2).
2.4.1.1. N-(3,5-dinitrobenzoyl)-N′,N′-dibutylthiourea [HL1]. Blackish brown in semi-solid
state. M.p.: 92–93 °C. Yield: 3.4 g (78%). IR (νmax/cm−1): 3206 (NH), 2955, 2847 (C–H),
1
1685 (C=O), 1261 (C=S). H NMR (400 MHz, CDCl3) in δ (ppm) and J (Hz): δ 9.10
(t, 1H, J = 1.8), 8.85 (d, 2H, J = 1.8), 8.38 (bs, 1H, CONH), 3.97 (t, 2H, N-CH2), 3.52
(t, 2H, N–CH2), 1.83 (m, 2H, –CH2–), 1.68 (m, 2H, –CH2–), 1.46 (m, 2H, –CH2–), 1.32
(m, 2H, –CH2–), 1.01 (t, 3H, CH3), 0.92 (t, 3H, CH3). Anal. Calcd for C16H22N4O5S: C,
50.25; H, 5.80; N, 14.65; S, 8.38. Found: C, 50.23; H, 5.83; N, 14.67; S, 8.35.
2.4.1.2. N-(4-nitrobenzoyl)-N′,N′-dibutylthiourea [HL2]. Light yellow. M.p.: 86–87 °C.
Yield: 3.3 g (86%). IR (νmax/cm−1): 3227 (NH), 2931, 2840 (C–H), 1685 (C=O), 1259
1
(C=S). H-NMR (400 MHz, CDCl3) in δ (ppm): 8.41 (br s, 1H, CONH), 8.29 (d, 2Hmeta
,
p-nitrophenyl), 8.05 (d, 2Hortho, p-nitrophenyl), 3.97 (t, 2H, N–CH2), 3.55 (t, 2H, N–CH2),
1.97 (m, 2H, CH2), 1.75 (m, 2H, CH2), 1.42 (m, 2H, CH2), 1.32 (m, 2H, CH2), 1.01 (t,3H,
–CH3),0.92 (t,3H, –CH3); Anal. Calcd for C16H23N3O3S: C, 56.95; H, 6.87; N, 12.45; S,
9.50. Found: C, 56.93; H, 6.89; N, 12.44; S, 9.54.
2.4.2. General method for the preparation of acylthioureas copper complexes. A solu-
tion of copper nitrate (0.01 M) in methanol (35 mL) was added dropwise to a solution of
the ligand in a 1 : 2 ratio with a small excess of ligand in ethanol (35 mL) at room tempera-
ture, and the resulting mixture was stirred for 3 h. The reaction mixture was filtered, washed
with ethanol, and re-crystallized from a THF : acetonitrile mixture (1 : 1).
2.4.2.1. Bis[N-(3,5-dinitrobenzoyl)-N′,N′-dibutylthiourea]copper(II), [Cu(L1)2]. Quantities
used were 3.82 g (0.01 M) ligand (HL1) and 1.20 g (0.005 M) copper nitrate in ethanol.
Green shining small particles. Yield: 3.8 g (77%). IR (νmax/cm−1): 2929, 2856 (Ar–H),
1505 (C–O), 1537 (C–N), 1142 (C–S); Anal. Calcd for C32H42N8O10S2Cu: C, 46.51;

2946
S. Saeed and R. Hussain
H, 5.12; N, 13.56; S, 7.76; Cu, 7.69. Found: C, 46.32; H, 5.27; N, 13.57; S, 7.73; Cu, 7.03.
Mass (MS-APCI) (major fragment, m/z): 826[M+, C32H42N8O10S2Cu].
2.4.2.2. Bis[N-(4-nitrobenzoyl)-N′,N′-dibutylthiourea]copper(II), [Cu(L2)2]. Quantities used
were 3.37 g (0.01 M) ligand (HL2) and 1.20 g (0.005 M) copper nitrate in ethanol. Light
green. Yield: 3.4 g (76%). IR (νmax/cm−1): 2929, 2852 (Ar–H), 1506 (C–O), 1532 (C-N),
1139 (C–S); Anal. Calcd for C32H44N6O6S2Cu: C, 52.19; H, 6.02; N, 11.41; S, 8.71; Cu,
8.63. Found: C, 51.87; H, 6.34; N, 11.48; S, 8.70; Cu, 8.37. Mass (MS-APCI) (major
fragment, m/z): 736[M+, C32H44N6O6S2Cu].
3. Results and discussion
3.1. Synthesis and spectroscopic characterization
The synthetic pathway for symmetrical acylthiourea derivatives and their copper complexes
is outlined in scheme 2. The acylthiourea ligands and copper complexes were synthesized
according to reported procedures [40–45] with minor modifications. The use of phase trans-
fer catalyst (PTC) is a well-known method and is extensively applied in a heterogeneous
reaction system [46, 47]. To improve the yield of aroylthiourea ligands, we have used
TBAB as PTC in our designed reactions. The reaction proceeds via a nucleophilic addition
of the secondary amine to the acylisothiocyanate. The solid-state IR spectra of the acy-
lthiourea derivatives and the metal complexes from 4000 to 400 cm−1 were compared and
assigned on careful comparison [48]. N,N′-disubstituted thioureas behave both as monoden-
tate and bidentate ligands, depending upon the reaction conditions. The characteristic bands
of N,N′-disubstituted thioureas are 3206–3227 (NH), 2840–2931 Ph (CH), 1685 (C=O) and
1259–1261 (C=S), and there is a slight shift of (C=O) and (C=S) group stretching
frequencies due to coordination of the ligands to copper.
Acythioureas usually are bidentate to transition-metal ions through the acyl oxygen and
sulfur [49, 50]. IR spectra of the complexes showed significant changes when compared
with IR spectra of the corresponding ligands. The IR spectra of the complexes showed
absorptions at υmax/cm−1: 2856–2929 Ph (CH), 1506 (C–O), 1533 (C–N), and 1142 (C–S).
The most striking changes are the N–H stretching frequency at 3226 cm−1 in the free
ligands, which disappears in agreement with both ligands and complex structures and with
the complexation reaction. This indicates that the loss of the proton comes from nitrogen of
the (NH–CO) amide group. Another striking change is observed with the carbonyl
stretching vibrations. The vibrational frequencies due to the carbonyl (1671 cm−1) group in
the free ligand shift to lower frequencies upon complexation, confirming that the ligand is
coordinated to copper(II) through the O, S-donors [51–55]. IR spectroscopic data of the
complexes with the values of the free acylthiourea ligands indicate that coordination of
acylthiourea to copper has a significant effect on υ(N–H), υ(C=O) and υ(C=S) frequencies.
3.2. Single-crystal X-ray crystallography
The molecular structure diagram of [(Bu)2NC(S)NC(O)C6H3(4-NO2)]2Cu(II) is shown in
figure 1. Selected bond lengths and angles are listed in table 1. The structure of the copper
complex is in a cis-configuration with a slightly distorted square planar coordination of

Copper sulfide nanoparticles
2947
O
R3
R2
Cl
NaSCN
TBAB
Dry acetone
R1
O
S
C
N
R3
R2
( Sec. amine)
R1
O
S
R3
R2
R'
NH
N
R
( HL1, HL2 )
R1
Copper nitrate
R3
R2
R2
R3
R1
R1
O
S
O
N
S
N
N
M
R
N
R'
R
R'
Cu (L1)2, Cu (L2)2
M = Cu(II)
Compound
I.D
R1
R2
R3
R = R’
HL1
NO2
H
NO2
H
H
NO2
H
NO2
H
NO2
H
butyl
butyl
butyl
butyl
HL2
Cu(L1)2
Cu(L2)2
NO2
Scheme 2. Preparation of ligands and their copper complexes.

2948
S. Saeed and R. Hussain
Figure 1. X-ray structure of (Cu(L2)2).
copper by two oxygens and two sulfurs. One n-butyl group was disordered in two positions
at occupancies of 0.782(16) and 0.218(16), respectively. Crystals were obtained by
dissolving 0.5 g of the crude product in minimum of THF : acetonitrile (1 : 1) to give a
green clear solution, which was evaporated at room temperature for one week to deposit
dark green blocks. Crystal data: C32H44N6O6S2Cu, triclinic, space group P−1, a = 8.585(2)
Å, b = 12.347(3) Å, c = 17.326(4) Å, β = 89.30(4)°, V = 3444.5(3) Å3, T = 300 K, Z = 2,
F (0 0 0) = 774, Dx = 1.337 g cm−3, μ = 0.76 mm−1.
3.3. Characterization of copper sulfide nanoparticles deposited from [(Bu)2NC(S)NC
(O)C6H3(3,5-NO2)2]2Cu(II), [Cu(L1)2]. The XRD pattern for the CuS nanoparticles syn-
thesized from [Cu(L1)2] is shown in figure 2. The synthesis of copper sulfide nanoparticles
was carried out at 170 and 230 °C. No deposition was obtained below 170 °C [figure 2(a)].
The material was almost non-crystalline at this low temperature. At 230 °C [figure 2(c)] the
XRD pattern of Cu9S5 (digenite) nanoparticles shows diffractions of rhombohedral Cu9S5
and the space group R-3 m(166) with major diffraction peaks of (0 0 1 5), (1 0 7), (1 0 1 0),
(0 1 1 4), (1 1 0), and (2 0 5) planes (ICDD: 026-0476) and figure 2(b) shows the literature
XRD pattern of Cu9S5. The TEM image (figure 3) showed the particles are trigonal crystal-
lites. There was a certain degree of agglomeration and size of the particles could be approx-
imated to 1–2 nm in length. The particle sizes of all the deposited crystallite phases from
[Cu(L1)2] and [Cu(L2)2] were also estimated using the FWHM from Scherer’s relation and
are of the order of 3.1–52 nm, respectively. The experimental and calculated lattice parame-
ters are cell parameters, cell volume, d-spacing, 2θ, hkl planes with respect to (1 1 0) plane
for both [Cu(L1)2] and [Cu(L2)2] as presented in table 2.

Copper sulfide nanoparticles
2949
Table 1. Selected bond lengths (Å) and angles (°) for [Cu(L2)2].
Bond lengths (Å)
Cu1–O1
Cu1–O4
Cu1–S1
Cu1–S2
S1–C8
1.919(2)
1.949(2)
2.2448(11)
2.2610(10)
1.731(4)
1.715(4)
1.262(4)
1.212(4)
1.212(4)
1.260(4)
1.190(5)
1.192(5)
1.316(4)
1.335(4)
1.480(5)
1.351(4)
1.459(5)
1.482(5)
1.346(4)
1.462(5)
1.468(5)
1.509(5)
1.380(5)
1.383(5)
1.380(5)
0.9300
C14–C15
C14–H14A
C14–H14B
C15–C16
C15–H15A
C15–H15B
C16–H16A
C16–H16B
C16–H16C
C17–C18
C18–C23
C18–C19
C19–C20
C19–H19
C20–C21
C20–H20
C21–C22
C25–C26
C25–H25A
C25–H25B
C26–C27
C26–H26A
C26–H26B
C27–C28
1.517(5)
0.9700
0.9700
1.519(6)
0.9700
0.9700
0.9600
0.9600
0.9600
1.498(5)
1.380(5)
1.391(5)
1.376(5)
0.9300
1.366(5)
0.9300
1.372(5)
1.493(6)
0.9700
0.9700
1.526(6)
0.9700
0.9700
1.451(8)
0.9700
0.9700
0.9600
S2–C24
O1–C1
O2–N2
O3–N2
O4–C17
O5–N5
O6–N5
N1–C1
N1–C8
N2–C5
N3–C8
N3–C13
N5–C21
N6–C24
N6–C29
N6–C25
C1–C2
C2–C3
C2–C7
C3–C4
C3–H3
C4–C5
C27–H27A
C27–H27B
C28–H28A
1.378(5)
Bond angles (°)
O1–Cu1–O4
O1–Cu1–S1
O4–Cu1–S1
O1–Cu1–S2
O4–Cu1–S2
S1–Cu1–S2
C8–S1–Cu1
C24–S2–Cu1
C1–O1–Cu1
C17–O4–Cu1
C1–N1–C8
O3–N2–O2
O3–N2–C5
O2–N2–C5
C8–N3–C13
C8–N3–C9
C13–N3–C9
C17–N4–C24
O5–N5–O6
O5–N5–C21
O6–N5–C21
C24–N6–C29
C24–N6–C25
C29–N6–C25
O1–C1–N1
84.88(10)
93.14(8)
176.40(9)
176.75(9)
92.89(8)
88.96(4)
107.78(13)
104.65(12)
132.5(2)
130.7(2)
124.2(3)
123.1(4)
118.0(4)
118.9(4)
122.7(3)
120.5(3)
116.4(3)
124.6(3)
122.8(4)
117.6(4)
119.6(4)
123.6(3)
120.7(3)
115.8(3)
131.3(3)
H15A–C15–H15B
C15–C16–H16A
C15–C16–H16B
H16A–C16–H16B
C15–C16–H16C
H16A–C16–H16C
H16B–C16–H16C
O4–C17–N4
107.7
109.5
109.5
109.5
109.5
109.5
109.5
129.9(3)
116.1(3)
114.0(3)
118.5(3)
121.7(3)
119.8(3)
120.4(3)
119.8
O4–C17–C18
N4–C17–C18
C23–C18–C19
C23–C18–C17
C19–C18–C17
C20–C19–C18
C20–C19–H19
C18–C19–H19
C21–C20–C19
C21–C20–H20
C19–C20–H20
C20–C21–C22
C20–C21–N5
119.8
119.1(3)
120.5
120.5
122.0(4)
119.6(4)
118.3(4)
118.3(4)
120.9
C22–C21–N5
C23–C22–C21
C23–C22–H22
C21–C22–H22
120.9

2950
S. Saeed and R. Hussain
Figure 2. XRD pattern of Cu9S5 nanoparticles prepared at (a) 170 °C, (c) 230 °C from precursor [Cu(L1)2], and
(b) Literature XRD pattern of Cu9S5.
Figure 3. TEM image of Cu9S5 nanoparticles prepared from [Cu(L1)2] at 230 °C.
Table 2. The experimental and calculated lattice parameters of deposited copper sulfide nanoparticles prepared
from precursors ([Cu(L1)2], [Cu(L2)2]).
Cell parameters,
Å
Cell volume,
Å3
d-
spacing,
Å
2θ
JCPDS hkl
46.2 110
Precursors
Obs
Obs
STD
Obs
STD
Crystallite phase
[Cu(L1)2] and [Cu 46.12
(L2)2]
1.95
a
c
4.25
53.93 48.00
3.91 610.52 638.44
Cu9S5
(Rhombohedral)

Copper sulfide nanoparticles
2951
3.4. Characterization of copper sulfide nanoparticles deposited from [(Bu)2NC(S)NC
(O)C6H4(4-NO2)]2Cu(II), [Cu(L2)2]. The XRD pattern for the copper sulfide nanoparticles
synthesized from [Cu(L2)2] is shown in figure 4. The synthesis of copper sulfide nanoparti-
cles was carried out at 170 and 230 °C. No deposition was obtained below 170 °C [figure
4(a)]. At 230 °C [figure 4(c)] the XRD pattern of Cu9S5 (digenite) nanoparticles shows dif-
fractions of rhombohedral Cu9S5 and the space group R-3 m(166) with major diffraction
peaks of (0 0 1 5), (1 0 7), (1 0 1 0), (0 1 1 4), (1 1 0), and (2 0 5) planes (ICDD: 026-0476)
and figure 4(b) shows the literature XRD pattern of Cu9S5. The TEM image (figure 5)
showed the nanoparticles are in trigonal crystallites. There was a certain degree of
agglomeration and size of the particles could be approximated to 12–50 nm in length.
Figure 4. XRD pattern of Cu9S5 nanoparticles prepared at (a) 170 °C, (c) 230 °C from [Cu(L2)2], and (b) Literature
XRD pattern of Cu9S5.
Figure 5. TEM image of Cu9S5 nanoparticles prepared from [Cu(L2)2] at 230 °C.

2952
S. Saeed and R. Hussain
4. Conclusion
We have synthesized and characterized two symmetrical copper(II) complexes, bis[N-(3,5-
dinitrobenzoyl)-N′,N′-dibutylthiourea]copper(II) and bis[1-(4-nitrobenzoyl)-3,3-dibutylthiou-
rea]copper(II). The single-crystal X-ray structure of bis[1-(4-nitrobenzoyl)-3,3-dibutylthiou-
rea]copper(II) has been determined from single-crystal X-ray diffraction data. The
synthesized copper complexes were used as single-source precursors for deposition of cop-
per sulfide nanoparticles. The single-source precursors [Cu(L1)2 and Cu(L2)2] deposited tri-
gonal crystallites having 1–2 nm and 12–50 nm in length, respectively. These newly
synthesized copper complexes may be applicable precursors for the deposition of TOPO
capped (tri-n-octylphosphineoxide) nanoparticles of copper sulfide.
Supplementary crystallographic data
Crystallographic data for the structure reported in this article have been deposited with the
Cambridge Crystallographic Data Center, CCDC 879352 (Cu(L2)2). Copies of this informa-
tion may be obtained free of charge from the Director, CCDC, 12 Union Road, Cambridge,
CBZ IEZ, UK. Facsimile (44) 01223 336 033, E-mail: deposit@ccdc.cam.ac.uk or http://
www.ccdc.cam.ac.uk/deposit.
Acknowledgement
Dr Sohail Saeed would like to acknowledge the Higher Education Commission (HEC),
Government of Pakistan for financial support.
Supplemental data
Supplemental data for this article can be accessed here [http://dx.doi.org/10.1080/00958972.2014.950958].
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