(Benzyl isocyanide)gold(I) pyrimidine-2-thiolate complex: Synthesis and biological activity

Article abstract of DOI:10.1002/aoc.4200

The reaction of [(Me₂S)AuCl] with an equimolar amount of benzyl isocyanide (PhCH₂NC) ligand led to the formation of complex [(PhCH₂NC)AuCl] (1). The solid-state structure of 1 was determined using the X-ray diffraction method. Through a salt metathesis reaction, the chloride ligand in 1 was replaced by pyrimidine-2-thiolate (SpyN^?) to afford the complex [(PhCH₂NC)Au(η¹-S-Spy)] (2), which was characterized spectroscopically. The cytotoxic activities of 1 and 2 were evaluated against three human cancer cell lines: ovarian carcinoma (SKOV3), lung carcinoma (A549) and breast carcinoma (MCF-7). Complex 2 showed higher cytotoxicity than cisplatin against SKOV3 and MCF-7 cancer cell lines. It showed a strong anti-proliferative activity with IC₅₀ of 7.80, 6.26 and 6.14 μM, compared with that measured for cisplatin which was 7.62, 12.36 and 11.47 μM, against A549, SKOV3 and MCF-7 cell lines, respectively. The induction of cellular apoptosis by 2 was also studied on MCF-7 cell line. Our results indicated that 2 could induce apoptosis in cancerous cells in a dose-dependent manner.

Full text of DOI:10.1002/aoc.4200

Received: 9 October 2017
DOI: 10.1002/aoc.4200
Revised: 2 November 2017
Accepted: 2 November 2017
F U L L P A P E R
(Benzyl isocyanide)gold(I) pyrimidine‐2‐thiolate complex:
Synthesis and biological activity
Masood Fereidoonnezhad1
| Hamid R. Shahsavari2
| Elaheh Lotfi1 |
Mojgan Babaghasabha2 | Motahareh Fakhri1 | Zeinab Faghih3 | Zahra Faghih4 |
M. Hassan Beyzavi5
1 Department of Medicinal Chemistry,
The reaction of [(Me2S)AuCl] with an equimolar amount of benzyl isocyanide
(PhCH2NC) ligand led to the formation of complex [(PhCH2NC)AuCl] (1).
The solid‐state structure of 1 was determined using the X‐ray diffraction
method. Through a salt metathesis reaction, the chloride ligand in 1 was
replaced by pyrimidine‐2‐thiolate (SpyN−) to afford the complex [(PhCH2NC)
Au(η1‐S‐Spy)] (2), which was characterized spectroscopically. The cytotoxic
activities of 1 and 2 were evaluated against three human cancer cell lines: ovar-
ian carcinoma (SKOV3), lung carcinoma (A549) and breast carcinoma (MCF‐7).
Complex 2 showed higher cytotoxicity than cisplatin against SKOV3 and MCF‐7
cancer cell lines. It showed a strong anti‐proliferative activity with IC50 of 7.80,
6.26 and 6.14 μM, compared with that measured for cisplatin which was 7.62,
12.36 and 11.47 μM, against A549, SKOV3 and MCF‐7 cell lines, respectively.
The induction of cellular apoptosis by 2 was also studied on MCF‐7 cell line.
Our results indicated that 2 could induce apoptosis in cancerous cells in a
dose‐dependent manner.
School of Pharmacy, and Cancer,
Environmental and Petroleum Pollutants
Research Center, Ahvaz Jundishapur
University of Medical Sciences, Ahvaz,
Iran
2 Department of Chemistry, Institute for
Advanced Studies in Basic Sciences
(IASBS), Yousef Sobouti Blvd, Zanjan
45137‐66731, Iran
3 Pharmaceutical Sciences Research
Center, Shiraz University of Medical
Sciences, Shiraz, Iran
4 Shiraz Institute for Cancer Research,
School of Medicine, Shiraz University of
Medical Sciences, Shiraz, Iran
5 Department of Chemistry and
Biochemistry, University of Arkansas,
Fayetteville, AR 72701, U.S.A.
Correspondence
Hamid R. Shahsavari, Department of
Chemistry, Institute for Advanced Studies
in Basic Sciences (IASBS), Yousef Sobouti
Blvd, Zanjan 45137‐66731, Iran.
Email: shahsavari@iasbs.ac.ir
KEYWORDS
apoptosis study, biological activity, gold complexes, isocyanide ligand, thiolate ligand
M. Hassan Beyzavi, Department of
Chemistry and Biochemistry, University of
Arkansas, Fayetteville, AR 72701, U.S.A.
Email: beyzavi@uark.edu
Funding information
University of Arkansas, Institute for
Advanced Studies in Basic Sciences
(IASBS) Research Council and Ahvaz
Jundishapur University of Medical
Sciences.
Appl Organometal Chem. 2018;e4200.
wileyonlinelibrary.com/journal/aoc
Copyright © 2018 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.4200

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FEREIDOONNEZHAD ET AL.
The SMe2 ligand in A is a good leaving group and can be
readily substituted by one equivalent of benzyl isocyanide
(PhCH2NC) which afforded the corresponding complex
[(PhCH2NC)AuCl] (1).[38] Hashmi and co‐workers[13,38]
have also reported 1, but utilizing a different precursor
complex: [(tht)AuCl] (tht = tetrahydrothiophene). We
further treated 1 with potassium pyrimidine‐2‐thiolate
(KSpyN) in a 1:1 molar ratio which yielded complex
[(PhCH2NC)Au(η1‐S‐Spy)] (2) as a new complex through
a salt metathesis reaction (Scheme 1). Both complexes
are air‐stable, colourless solids that were obtained in good
yields. Complexes 1 and 2 were characterized using NMR
and infrared (IR) spectroscopy and elemental analysis,
and the solid‐state structure of 1 was further confirmed
for the first time using single‐crystal X‐ray diffraction.
IR spectra of 1 and 2 (in KBr) exhibited distinctive
bands at 2260 and 2247 cm−1, respectively, which are
related to the stretching frequency of isocyanide function.
The observed bands had a hypsochromic shift with respect
to that of the PhCH2NC free ligand (2149 cm−1)[39,40] and
they supported standard coordination (direct end‐on
mode) of the isocyanide function to the Au atom in both
complexes.[28,35]
1 | INTRODUCTION
Since the discovery of cisplatin in the mid‐1960s,[1] there
has been a growing attention towards Pt‐based anti‐prolif-
erative drugs. However, the Pt‐based treatment of cancer
is significantly impeded by the development of resistance
and severe side‐effects. Sulfur‐containing biomolecules
play a pivotal role in Pt anti‐proliferative chemotherapy
because of their high affinity to the Pt(II) ion.[2,3] Irrevers-
ible and strong binding of cisplatin to intracellular
thiolato donors is hypothesized to be an important cause
of inactivation. As a result, novel metal‐based anti‐
tumour complexes with pharmacological characteristics
other than Pt‐based drugs are an important target in mod-
ern drug design and medicinal chemistry. In recent years,
Au‐based complexes have received increasing consider-
ation because of their potent inhibition of cancer cell
growth which is mainly caused by non‐cisplatin‐like
mechanisms of action.[4]
Gold is an important transition metal that has two
significant oxidation states, +1 and +3.[5] It is believed
that the most stable oxidation state of Au is Au(I) and
it forms usual linear complexes by coordination of two
ligands.[6] The stability of Au(I) complexes is straightfor-
wardly modified by the nature of the coordinating
ligands, i.e. donor atoms.[7–10] These complexes usually
comprise soft donor atoms such as carbon,[11–17] phos-
phorus[18–21] and sulfur.[21–24]
Organic compounds containing a thiol group (RSH) or
its corresponding anion form, called thiolate (RS−), are
chemically unique and can be used as a source of sulfur
donor ligands.[3,25–27] Several complexes based on thiolate
ligands especially of the type L−Au(I)−SR have been pre-
pared. In these complexes L is a neutral ligand such as
phosphine,[24,28–30] N‐heterocyclic carbene[31–33] or
isocyanide.[28,34–36] In general, the presence of the various
L donor ligands and thiolate ligands in the structure of
these complexes leads to a wide range of applications par-
ticularly in cancer treatment.[24,29,31,33]
The present paper demonstrates the synthesis, struc-
tural characterization and biological activity of new Au(I)
complexes with isocyanide and thiolate ligands. The bio-
logical activity was evaluated on three different cancer cell
lines. In addition, the study included an investigation of
the capacity of these compounds to induce apoptosis.
1
The H NMR and 13C{1H} NMR spectra of 1 and 2
(in CDCl3) displayed signal resonances due to the
PhCH2NC ligand in expected regions (similar to the free
ligand,[39,40] with slight shifts) and a simple pattern for
the SpyN ligand in 2 (Figures S1 and S2). Also, in the
13C{1H} NMR spectra of both complexes, Ce and Cf of
PhCH2NC ligand indicated a resolving coupling with
nitrogen nucleus (14N) which is a characteristic feature
for numerous isocyanide ligands and their complexes
(Figures S1 and S2).[12,13]
Single‐crystal X‐ray diffraction was carried out using 1
to determine its molecular structure, and crystallographic
data are collected in Table S1. Appropriate crystals of 1
were obtained from its CH2Cl2 solution with slow layer
diffusion of n‐hexane. This complex crystallizes in the
monoclinic crystal system (space group P21/c). The
ORTEP view of 1 is shown in Figure 1 and selected bond
lengths and angles are provided in the caption. Complex 1
has a quasilinear C2–N1–C1–Au–Cl1 skeleton extending
from the centre of benzylic carbon atom of the isocyanide
ligand to the chloride atom. The C1―Au―Cl1 (177.7(4)°)
and C1―N1―C2 (176.8(14)°) angles are close to 180°.
The Au―C1 and Au―Cl1 bond distances are close to
the values observed for (isocyanide)Au(I) halide com-
plexes like [(PhNC)AuCl].[12] In the lattice of this struc-
ture all molecular units are crystallographically
equivalent and the molecules are aggregated to form an
infinite zigzag chain[12,41] with a sequence of the mono-
mers in an antiparallel arrangement (Figure S3). Addi-
tionally, a network of hydrogen bonds arises between
2 | RESULTS AND DISCUSSION
2.1 | Synthesis and characterization of
complexes
The precursor complex [(Me2S)AuCl] (A) was prepared
according to the report of Puddephatt and co‐workers.[37]

FEREIDOONNEZHAD ET AL.
3 of 7
against SKOV3 and MCF‐7 cancer cell lines. However,
its cytotoxicity against the A549 cell line was comparable
with that of cisplatin. It showed a strong anti‐proliferative
activity with IC50 of 7.80, 6.26 and 6.14 μM, compared
with that measured for cisplatin which was 7.62, 12.36
and 11.47 μM, against A549, SKOV3 and MCF‐7 cell lines,
respectively. Complex 1 also showed a moderate anti‐
tumour effect, comparable with that of cisplatin, espe-
cially against MCF‐7 cell line with IC50 of 10.15 μM
(Figure 2). According to these results, the factors affecting
the activity of the synthesized Au(I) complexes can be
obtained and the relationship between structure and
activity could be acquired. Based on the structure, it can
be concluded that the presence of thiolate ligand (pyrimi-
dine‐2‐thiolate in 2) increases the cytotoxicity. The pres-
ence of chloro group instead of thiolate ligand decreases
the anti‐proliferative activity. Also, 2 displays higher cyto-
toxicity against MCF‐7 cell line than similar complexes
such as phosphine‐bridged dinuclear Au(I) alkynyl,[42]
SCHEME 1 Synthetic routes for preparation of 1 and 2
Au(I)–alkynyl
chromones[43]
and
Au(I)–carbene
complexes.[44]
FIGURE 1 Representation of X‐ray crystal of 1 showing all non‐
hydrogen atoms as 40% thermal ellipsoids. Selected geometric
parameters: bond lengths (Å) Au1–C1, 1.932(16); Au1–Cl1, 2.263(4);
N1–C1, 1.129(17); N1–C2, 1.43(2); bond angles (°) C1–Au1–Cl1,
177.7(4); Au1–C1–N1, 177.6(12); C1–N1–C2, 176.8(14); N1–C2–C3,
111.1(14)
2.3 | Apoptotic effect of 2 on MCF‐7 cell line
Apoptosis, or programmed cell death, is a normal process
that plays an important role in maintaining tissue homeo-
stasis during embryonic development as well as patholog-
ical conditions through removal of unwanted or damaged
cells. In the present study we used BioLegend's FITC
Annexin V Apoptosis Detection Kit with PI (BioLegend,
USA) to specifically identify apoptotic and necrotic cells
during treatment by 2. Annexin V is one of the intracellu-
lar proteins that can bind to phosphatidylserine (PS)
which is normally found on the intracellular leaflet of
the plasma membrane in live cells. During early apopto-
sis, as a result of losing membrane asymmetry, PS translo-
cates to the external leaflet and therefore can be
specifically targeted by fluorochrome‐labelled Annexin
V. Translocation of PS is followed by the loss of mem-
brane integrity. Therefore, we also simultaneously used
7‐aminoactinomycin D (7‐AAD) to distinguish between
necrotic and apoptotic cells. 7‐AAD is a DNA binding
reagent with a high constant which is efficiently excluded
by live healthy as well as early apoptotic cells, but pene-
trates into the nucleus of damaged cells, i.e. late‐stage
apoptotic cells and necrotic cells, and stains the DNA.
To determine the dose‐dependent effect of 2, the three
dilutions of this compound with 2.5, 5 and 10 μM concen-
trations were prepared and the apoptotic effects was
assessed on MCF‐7 cell line. As can be seen in Figure 3,
the percentage of cells in early apoptotic phase markedly
increased from 4.55% in untreated cells to 15.70, 64.40
and 71.60% in cells treated with 2.5, 5 and 10 μM of 2,
hydrogen atoms of benzylic carbons and chloride ligands
(Figure S3). In this supramolecular arrangement, no
aurophilic interactions are observed between neighbour
Au atoms (Au–Au distances are 4.519–4.570 Å). This
observation may be related to the close antiparallel pack-
ing in layers, forcing the Au atoms into alternating posi-
tions above and below the plane.[12,41]
2.2 | Biological activity
The in vitro cytotoxicity effects of 1 and 2 were evaluated
on three cancer cell lines: ovarian carcinoma (SKOV3),
lung carcinoma (A549) and breast carcinoma (MCF‐7).
As evident from Table 1, the most active compound of this
series, 2, exhibited greater cytotoxicity than cisplatin
TABLE 1 In vitro cytotoxic activity of gold complexes against
cancer cell lines
IC50 SD (μM)
Complex
1
A549
SKOV3
MCF‐7
22.66 3.76
22.25 3.56
10.15 1.15
2
7.80 0.64
7.62 0.68
6.26 0.72
6.14 0.41
Cisplatin
12.36 1.07
11.47 1.29

4 of 7
FEREIDOONNEZHAD ET AL.
FIGURE 2 IC50 values of 1 and 2
against A549, SKOV3 and MCF‐7 cancer
cell lines
FIGURE 3 Anti‐apoptotic effect of 2 on
MCF‐7 cell line. Compared to untreated
cells, the percentage of MCF‐7 cells in early
apoptotic phase (7AAD−/Annexin V+)
markedly increased in the cells treated
with 2.5, 5 and 10 μM of 2 in a dose‐
dependent manner. 7AAD stains dead
cells. 7AAD−/Annexin V+: early
apoptosis; 7AAD+/Annexin V+: late
apoptosis; 7AAD+/Annexin V−: necrosis;
7AAD−/Annexin V−: viable cells
respectively. These results show that this compound can
induce apoptosis in cancerous cells in a dose‐dependent
manner.
activities. While phosphine and nitrogen donors are well
explored, herein, a new sulfur‐based Au complex, 2, is
reported. The linear d10 two‐coordinate complex 1 is
readily prepared in high yield by replacement of
dimethylsulfide ligand in A with benzyl isocyanide.
NMR spectroscopy and X‐ray diffraction confirmed the
structure of 1. The chemistry of 1 was explored in a salt
metathesis reaction. In this reaction an anion exchange
between 1 and potassium pyrimidine‐2‐thiolate occurs
3 | CONCLUSIONS
Due to the limitations of cisplatin, Au complexes have
received considerable attention for their anti‐tumour

FEREIDOONNEZHAD ET AL.
5 of 7
leading to the formation of 2. Its structure was character-
ized using NMR spectroscopy. The cytotoxic activities of 1
and 2 were screened against various cancer cell lines. The
in vitro results revealed that 2 had reasonable IC50 and the
highest activity, while 1 displayed less cytotoxic activity.
Additional mechanistic investigation revealed that 2
induced significant cancer cell death by apoptosis.
solvent was concentrated to a small volume (ca 1 ml) under
vacuum, and n‐pentane (5 ml) was added to give 1 as a
white solid, which was filtered and washed with n‐pentane
(2 × 3 ml) and dried. Yield: 197 mg (83%); m.p. 138 °C. Anal.
Calcd for C8H7AuClN (349.57) (%): C, 27.49; H, 2.02; N,
4.01. Found (%): C, 27.61; H, 2.05; N, 4.06. IR (KBr, cm−1):
1
2260 (s, νC≡N). H NMR (CDCl3, δ, ppm): 4.87 (s, 2H, He),
3
4
7.35 (dd, JHH = 7.7 Hz, JHH = 1.4 Hz, 2H, Ha), 7.46–7.43
(m, 3H, Hb and Hc). 13C{H} NMR (δ, ppm): 48.2 (t, JCN
=
1
4 | EXPERIMENTAL
7 Hz, Ce), 127.5 (s, 2C, Ca), 129.4 (s, Cd), 129.6 (s, 2C, Cb),
129.7 (s, Cc), 135.6 (t, 1JCN = 26 Hz, Cf).
4.1 | General procedures and materials
All reactions were carried out under an argon atmosphere
using standard Schlenk techniques. NMR (1H and
13C{1H}) spectra were recorded with a Bruker Avance
DPX 400 MHz instrument and are referenced to the resid-
ual peak of the solvent, i.e. DMSO‐d6 or CDCl3 (1H and
13C). The chemical shifts were measured in ppm and cou-
pling constants in Hz. 13C{1H} NMR assignment was
achieved via DEPT 135. The melting point values were
measured using a Buchi 510. Microanalyses were per-
formed using a Vario EL CHNS elemental analyser. Fou-
rier transform IR spectroscopy with KBr pellets was
performed using a Bruker Vector 22 FT‐IR instrument.
Benzyl isocyanide (PhCH2NC) and pyrimidine‐2‐thiol
(HSpyN) were purchased from Acros and Aldrich, respec-
tively. Also, all solvents were purchased from Aldrich and
used without further purification. Complex A was pre-
pared as reported in the literature. [37] The chemical shift
assignments are based on the NMR labelling for the
ligands as shown in Figures S1 and S2.
4.4 | [(PhCH2NC)au(η1‐S‐spy)] (2)
An equimolar amount of KSpyN (43 mg, 0.29 mmol) was
dissolved in MeOH–acetone (2:8 ml) and added to a solu-
tion of 1 (100 mg, 0.29 mmol) in CH2Cl2 (15 ml). The reac-
tion mixture was stirred at room temperature for 15 h.
Then, solvent was removed under reduced pressure and
the residue was extracted with CH2Cl2 (10 ml). The
obtained colourless solution was filtered through celite
and the filtrate was concentrated to a small volume (ca
1 ml) under vacuum, and n‐pentane (5 ml) was added to
give 2 as a white solid, which was filtered and washed
with n‐pentane (3 × 3 ml) and dried. Yield: 86 mg (71%);
m.p. 125 °C. Anal. Calcd for C12H10AuN3S (425.26) (%):
C, 33.89; H, 2.37; N, 9.88. Found (%): C, 33.97; H, 2.41; N,
1
9.91. IR (KBr, cm−1): 2247 (s, νC≡N). H NMR (CDCl3, δ,
3
ppm): 4.84 (s, 2H, He), 6.82 (t, JHH = 4.9 Hz, 1H, Hi), 7.36
3
4
(dd, JHH = 7.5 Hz, JHH = 1.7 Hz, 2H, Ha), 7.45–7.42 (m,
3H, Hb and Hc), 8.34 (d, JHH = 4.9 Hz, 2H, Hh). 13C{1H}
3
NMR (δ, ppm): 48.0 (t, 1JCN = 7 Hz, Ce), 115.8 (s, Ci), 127.5
(s, 2C, Ca), 129.4 (s, Cd), 129.6 (s, 2C, Cb), 129.7 (s, Cc),
146.2 (t, 1JCN = 23 Hz, Cf), 156.8 (s, 2C, Ch), 179.6 (s, Cg).
4.2 | Potassium Pyrimidine‐2‐thiolate
(KSpyN)
To a solution of KOH (125 mg, 2.23 mmol) in MeOH
(5 ml), a solution of HSpyN (250 mg, 2.23 mmol) in
MeOH (10 ml) was added. The resulting yellow solution
was stirred at room temperature for 1 h, and then the sol-
vent was evaporated to dryness. The residue was treated
4.5 | Crystal structure determination and
refinement
X‐ray diffraction measurements were carried out using a
STOE IPDS
2
T
diffractometer with graphite‐
i
with PrOH (2 ml), and the resulting yellow solid was fil-
monochromated Mo Kα radiation. A single crystal suitable
for X‐ray analysis was obtained from CH2Cl2–n‐hexane
solution (at room temperature) and mounted on a glass
fibre and used for data collection. Cell constants and an
orientation matrix for data collection were obtained by
least‐square refinement of the diffraction data for 1. Dif-
fraction data were collected in a series of ω scans in 1°
oscillations and integrated using the STOE X‐AREA soft-
ware package.[45] Numerical absorption correction was
applied using X‐Red32 software. The structure was solved
by direct methods and subsequent difference Fourier maps
and then refined on F2 by a full‐matrix least‐squares proce-
dure using anisotropic displacement parameters. Atomic
tered and dried. Yield: 305 mg (91%). Anal. Calcd for
C4H3KN2S (150.24) (%): C, 31.98; H, 2.01; N, 18.65. Found
1
(%): C, 31.91; H, 2.03; N, 18.61%. H NMR (DMSO‐d6, δ,
3
3
ppm): 6.43 (t, JHH = 4.7 Hz, 1H, Hi), 7.94 (d, JHH
=
4.7 Hz, 2H, Hh). 13C{1H} NMR (δ, ppm): 110.8 (s, Ci),
155.2 (s, 2C, Ch), 188.4 (s, Cg).
4.3 | [(PhCH2NC)AuCl] (1)[13,38]
To a solution of A (200 mg, 0.68 mmol) in CH2Cl2 (20 ml),
1 eq. of PhCH2NC (83 μl, 0.68 mmol) was added. The mix-
ture was stirred at room temperature for 1 h and then the

6 of 7
FEREIDOONNEZHAD ET AL.
factors are from the International Tables for X‐ray Crystal-
lography. All non‐hydrogen atoms were refined with
anisotropic displacement parameters. Hydrogen atoms
were placed in ideal positions and refined as riding atoms
with relative isotropic displacement parameters. All
refinements were performed using the X‐STEP32,
SHELXL‐2014 and WinGX‐2013.3 programs.[46–50]
CCDC‐1571094 (for 1) contains the supplementary crystal-
lographic data for this paper. This data can be obtained
free of charge from the Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
4.6.3 | Apoptosis determination
MCF‐7 cells at 0.5 × 105 cells per millilitre of complete cul-
ture medium were seeded in a 24‐well culture plate. Follow-
ing 24 h incubation, the cells were treated with different
concentrations of 2 (2.5, 5 and 10 μM). Untreated samples
with equivalent DMSO concentration were used as the con-
trols. The cells were then incubated at 37 °C with 5% CO2
for 48 h. Treated and untreated cells were then harvested
and washed twice with cold cell staining buffer (BioLegend).
An amount of 50 μl of cells re‐suspended in Annexin V
binding buffer was then added to polystyrene round‐bottom
tubes (BD Bioscience, USA). Amounts of 2 μl of FITC‐conju-
gated Annexin V and 2 μl of 7‐AAD solution were added to
the cells and vortexed gently and incubated for 15 min at
room temperature in the dark. An amount of 300 μl of
Annexin V binding buffer was added to each tube and
analysed immediately using a four‐colour FACSCalibur flow
cytometer (BD Bioscience, USA) with appropriate setting.
The data were analysed using flowJo software packages.
4.6 | Biological assay
4.6.1 | Cell lines and cell culture
Human cancer cell lines MCF‐7, SKOV3 and A549 were
purchased from National Cell Bank of Iran (NCBI, Pas-
teur Institute, Tehran, Iran). All cells were cultured in
Dulbecco's modified Eagle medium (Biosera, UK), except
MCF‐7 cells which were cultured in RPMI 1640 (Sigma
Aldrich), supplemented with 10% foetal bovine serum
(Gibco, UK) and 1% penicillin–streptomycin and were
incubated at 37 °C in a humidified CO2 incubator.
ACKNOWLEDGEMENTS
M. H. B. gratefully acknowledges the financial support
through the startup funds from the University of Arkansas.
The Institute for Advanced Studies in Basic Sciences (IASBS)
Research Council, and Medicinal Chemistry, School of
Pharmacy, Ahvaz Jundishapur University of Medical Sci-
ences (B‐9557, B‐9637) are also gratefully acknowledged.
4.6.2 | MTT assay
Standard 3‐(4,5‐dimethylthiazol‐yl)‐2,5‐diphenyltetrazo-
lium bromide (MTT) assay was used for assessing cytotoxic
activities of 1 and 2 according to a known protocol.[3,51,52]
The cells were harvested and plated in 96‐well microplates
at a density of 1 × 104 cells per well in 100 μl of complete
culture medium. After 24 h of incubation, the cells were
treated with five different concentrations of the Au com-
plexes ranging from 1 to 100 μM in a triplicate manner.
Each compound was dissolved in DMSO. To avoid
bystander cytotoxic effect, the final concentration of
DMSO was maintained at about 0.1%. Following 48 h of
incubation at 37 °C in a humidified CO2 incubator, media
were completely removed and replaced with 100 μl of new
media containing 0.5 mg ml−1 MTT solution and the plate
were incubated for 3 h at room temperature. The media
containing MTT were then discarded, and 150 μl of DMSO
was added to each well to dissolve the formazan crystals.
The plates were then incubated for 30 min at 37 °C in
the dark. The absorbance of individual wells was read at
492 nm using a microplate ELISA reader. The data were
analysed using Excel 2013 and CurveExpert 1.4 and the
50% inhibitory concentration (IC50) of each compound
was determined. Each experiment was conducted three
times for each complex in a triplicate manner. Data are
presented as mean standard deviation (SD).
ORCID
Masood Fereidoonnezhad
3405-0228
Hamid R. Shahsavari
2185
http://orcid.org/0000-0003-
http://orcid.org/0000-0002-2579-
M. Hassan Beyzavi http://orcid.org/0000-0002-6415-8996
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How to cite this article: Fereidoonnezhad M,
Shahsavari HR, Lotfi E, et al. (Benzyl isocyanide)
gold(I) pyrimidine‐2‐thiolate complex: Synthesis
and biological activity. Appl Organometal Chem.
2018;e4200. https://doi.org/10.1002/aoc.4200
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