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Imine-N-Heterocyclic Carbenes as Versatile Ligands in Ruthenium(II) p-Cymene Anticancer Complexes: A Structure-Activity Relationship Study.
DOI: 10.1002/asia.201801058
Full Paper
Anticancer Complexes
Imine-N-Heterocyclic Carbenes as Versatile Ligands in
Ruthenium(II) p-Cymene Anticancer Complexes: A Structure–
Activity Relationship Study
Yuliang Yang, Lihua Guo,* Zhenzhen Tian, Xicheng Liu, Yuteng Gong, Hongmei Zheng,
Xingxing Ge, and Zhe Liu*[a]
Abstract: A family of novel imine-N-heterocyclic carbene
ruthenium(II) complexes of the general formula [(h6-p-cymene)Ru(C^N)Cl]PF6 (where C^N is an imine-N-heterocyclic
carbene chelating ligand with varying substituents) have
been prepared and characterized. In this imine-N-heterocyclic carbene chelating ligand framework, there are three potential sites that can be modified, which distinguishes this
class of ligand and provides a body of flexibilities and opportunities to tune the cytotoxicity of these ruthenium(II) complexes. The influence of substituent effects of three tunable
domains on the anticancer activity and catalytic ability in
converting coenzyme NADH to NAD + is investigated. This
family of complexes displays an exceedingly distinct anticancer activity against A549 cancer cells, despite their close
structural similarity. Complex 9 shows the highest anticancer
activity in this series against A549 cancer cells (IC50 =
14.36 mm), with an approximately 1.5-fold better activity
than the clinical platinum drug cisplatin (IC50 = 21.30 mm) in
A549 cancer cells. Mechanistic studies reveal that complex 9
mediates cell death mainly through cell stress, including cell
cycle arrest, inducing apoptosis, increasing intracellular reactive oxygen species (ROS) levels, and depolarization of the
mitochondrial membrane potential (MMP). Furthermore, lysosomal damage is also detected by confocal microscopy.
Introduction
platin still hinders its clinical applications and future development.[5] Therefore, obtaining new metal-based anticancer
drugs, which could broaden the spectrum of treatable cancers,
diminish side effects, and overcome platinum resistance, has
attracted tremendous attention.[6]
Ruthenium complexes have great potential as anticancer
agents as they are usually less toxic than cisplatin and hence
better tolerated in vivo.[7] For example, a host of ruthenium(II)
p-cymene complexes containing a wide range of ligands, including a-diimine ligands, imine-pyridine ligands, and pyridineN-heterocyclic carbene (NHC) ligands, has been developed
with the aim of improving their anticancer properties
(Scheme 1).[8] Marchetti and co-workers developed a series of
water-soluble ruthenium(II) p-cymene complexes containing
different a-diimine ligands (I, Scheme 1).[8a] The cytotoxicity of
these complexes strongly depended on the nature of the a-diimine N-substituents. Our group has designed a type of halfsandwich iridium(III) and ruthenium(II) complexes with iminepyridyl chelating ligands and achieved good selectivity and cytotoxicity (II, Scheme 1).[8b, c] Overall, the metal ions and bidentate ligands around the metal mainly determined the cancer
cell cytotoxicity and selectivity of these complexes. More recently, Hartinger and co-workers reported some pyridyl-NHC pcymene ruthenium(II) anticancer complexes (III, Scheme 1)[8d]
and investigated their anticancer properties and reactions with
biomolecules. In this system, introduction of varying substituents gave complexes with different properties, including stability in aqueous solution, reactivity toward biomolecules, in vitro
Although the research of anticancer agents has achieved remarkable progress over the past five decades, cancer remains
one of the leading causes of death worldwide.[1] Given the
rapid increase in cancer cases worldwide, the development of
novel anticancer drugs with high performance and low toxicity
has become an indispensable need. Organometallic complexes
have found wide applications in various fields, particularly as
catalysts[2] and anticancer agents.[3] At present, the most effective and well-studied class of metal-based anticancer agents,
cisplatin and its derivatives, have been successfully applied in
clinical treatment and shown high efficacy against lung, ovarian, neck, esophageal, and head cancers.[4] However, the undesirable side effects and easily acquired drug resistance of cis[a] Y. Yang, Prof. L. Guo, Z. Tian, Dr. X. Liu, Y. Gong, H. Zheng, X. Ge,
Prof. Z. Liu
Institute of Anticancer Agents Development and Theranostic Application
The Key Laboratory of Life-Organic Analysis and
Key Laboratory of Pharmaceutical Intermediates and Analysis of Natural
Medicine
Department of Chemistry and Chemical Engineering, Qufu Normal University
Qufu 273165 (China)
E-mail: guolihua@qfnu.edu.cn
liuzheqd@163.com
Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under:
https://doi.org/10.1002/asia.201801058.
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on anticancer activity and catalytic ability in converting coenzyme NADH to NAD + of the complexes were fully investigated.
This family of half-sandwich ruthenium(II) complexes exhibits
uncommonly different in vitro cytotoxicity, which is significantly correlated with the structure of the ligands. Initial cell death
mechanistic insights, including cell cycle, apoptosis induction,
mitochondrial membrane potential, reactive oxygen species
(ROS) level, and lysosomal damage, are also discussed. All
these studies point out that these novel ruthenium(II) organometallic complexes possess a variety of interesting biological
effects that make them attractive as a potentially promising
candidate for the development of anticancer agents.
Results and Discussion
Synthesis and characterization
Scheme 1. The structure of relevant ruthenium(II) complexes and our current
work.
The imine-N-heterocyclic carbene ligands (L1–L10) and novel
ruthenium(II) complexes (1–10) were prepared according to
well-established procedures, depicted in Scheme 2. A series of
versatile imine-N-heterocyclic carbene ligands were synthesized by a coupling reaction of the corresponding imidoyl
chlorides with N-substituted imidazole. Imine-N-heterocyclic
carbene silver complexes were usually used as effective transfer reagents to obtain other transition-metal complexes.[9]
Novel ruthenium(II) complexes 1–10 were synthesized in high
yields (60–87 %) from the corresponding (NHC)AgCl complex
with [(h6-p-cymene)RuCl2]2 by stirring at ambient temperature
overnight, and the corresponding ruthenium(II) complexes
were isolated as PF6 salts. All the synthesized ruthenium(II)
complexes were fully characterized by 1H and 13C NMR spectroscopy (Figures S1–S36 in the Supporting Information), CHN
elemental analysis, and mass spectrometry (Figures S37–S54 in
cytotoxicity, and cellular uptake. These results prompted us to
further investigate the effect of varying the substituents of
imine-N-heterocyclic carbene chelating ligands on the chemical
and biological reactivity of ruthenium(II) complexes.
Herein, a series of structurally similar half-sandwich ruthenium(II) complexes bearing versatile imine-N-heterocyclic carbene
ligands has been synthesized and systematically investigated
for their chemical reactivity, biological reactivity, catalytic ability
in transfer hydrogenation converting coenzyme NADH into
NAD + , and in vitro cytotoxicity against A549 cancer cells. To
the best of our knowledge, this form of imine-N-heterocyclic
carbene half-sandwich ruthenium(II) complexes is used for the
first time as anticancer agents. The effects of the substituents
Scheme 2. Synthetic routes for imine-N-heterocyclic carbene ligands L1–L10 and [(h6-p-cymene)Ru(C^N)Cl]PF6 complexes 1–10.
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Cl /H2O exchange more easily in diluted solutions with a
higher relative content of water, as in the case of cell culture.[10]
As a result, complex 9 was added in water and stirred at 310 K
for 24 h. Subsequently, the solid sample of complex 9 was recovered and dissolved in CDCl3 to repeat the 1H NMR spectra
(Figure S67 in the Supporting Information). There was also no
change in the 1H NMR spectra, which indicated that hydrolysis
also did not occur when a high content of water was employed. Complex 9 was also monitored by UV/Vis spectroscopy
in 5 % MeOH/95 % H2O (v/v) solution (Figure S68 in the Supporting Information) to further estimate the stability of these
complexes. The results obtained by UV/Vis spectroscopy in a
high content of water were consistent with the NMR analysis.
Overall, the stability studies suggest that the complexes have
sufficient stability for the preparation of samples for biological
assays.
Figure 1. X-ray crystal structures of compound of [(h6-p-cymene)Ru(L9)Cl]PF6 (9) with the thermal ellipsoids drawn at the 50 % probability
level. The hydrogen atoms and PF6 counterions have been omitted for
clarity. Selected bond lengths () and angles (deg): Ru C (centroid) = 1.7398,
Ru C1 = 2.022(6), Ru N3 = 2.132(5), Ru Cl1 = 2.4026(16); C1-Ru-N3 = 76.0(2),
C1-Ru-Cl1 = 78.6(2), N3-Ru-Cl1 = 87.53(14).
the Supporting Information). The characteristic peaks for the
central imidazolium carbon of these complexes were at d =
186.34–192.68 ppm in the 13C NMR spectra. Additionally, the
molecular structure of complex 9 was unambiguously confirmed by the X-ray crystallographic study (Figure 1 and Tables S1–S2 in the Supporting Information).
The structure–activity relationship study
The in vitro cytotoxicity of the ligands L1–L10, complexes 1–
10, and cisplatin against A549 cancer cells was examined after
a 24 h exposure period by using the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The widely
used clinical platinum drug cisplatin was included as a control.
All of the imine-N-heterocyclic carbene ligands showed very
low cytotoxicity against A549 cells (> 100 mm) and they were
thus deemed as inactive. On the other hand, although these
ruthenium(II) complexes are structurally analogous, they had
different anticancer activities. Subtle structural changes in the
ligand substituents can dramatically alter the cytotoxic activities of these complexes. As depicted in Table 1 and Figure 2,
complexes 1–4, and 6 were inactive (> 100 mm). However, the
other five complexes displayed anticancer activity toward A549
cancer cells comparable to or even higher than cisplatin. Notably, complex 9, the most cytotoxic one against the A549
cancer cells, exhibited approximately 1.5-fold greater activity
than cisplatin. Overall, the in vitro anticancer activity of the
test complexes was in the following order: 9 > cisplatin > 8 >
7 > 10 > 5.
X-ray crystal structures
A single crystal suitable for X-ray diffraction analysis was obtained from the slow diffusion of petroleum ether into a nearly
saturated solution of complex 9 in CH2Cl2/ethyl acetate. Their
structures and atom numbering schemes are shown in
Figure 1. Crystallographic data are shown in Table S1 (in the
Supporting Information), and selected bond lengths and
angles are listed in Table S2 (in the Supporting Information). As
shown in Figure 1, complex 9 adopts the expected half-sandwich pseudo-octahedral three-legged piano-stool arrangement,
and hence, the arene ring displays the common p-bonded h6coordination mode, whereas the imine-N-heterocyclic carbenetype ligand assumes a bidentate chelate coordination mode
(k2-C,N). The two rings of the five-membered chelate ring and
the imidazole ring are approximately coplanar. The Ru Cl
bond length is 2.4026(16) . The Ru–h6-p-cymene ligand (centroid) distance is 1.7398 . The orthometalated Ru C length
[Ru C = 2.022(6) ] is shorter than Ru N [Ru N = 2.132(5) ].
Table 1. Inhibition of the growth of A549 cancer cells by ligands L1–L10,
complexes 1–10, and cisplatin.[a]
Ligand
Stability studies
L1
L2
L3
L4
L5
L6
L7
L8
L9
L10
For the investigation of aqueous stability, studies were conducted by 1H NMR spectroscopy at 310 K for complexes 1–10,
which were dissolved in 30 % [D6]DMSO/70 % D2O (v/v). The
presence of [D6]DMSO ensured the solubility of the complex.
As shown in Figures S55–S64 (in the Supporting Information),
no additional peaks were observed in the 1H NMR spectra after
24 h. In addition, the 35Cl NMR spectra for complexes 4 and 9,
recorded on solutions in 60 % [D6]DMSO/40 % D2O (v/v) after
24 h, showed no evidence of free Cl ions (Figures S65–S66 in
the Supporting Information). It should be noted that some previously reported half-sandwich metal complexes may undergo
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IC50 [mm]
> 100
> 100
> 100
> 100
> 100
> 100
> 100
> 100
> 100
> 100
Complex
6
[(h -p-cymene)Ru(L1)Cl]PF6 (1)
[(h6-p-cymene)Ru(L2)Cl]PF6 (2)
[(h6-p-cymene Ru(L3)Cl]PF6 (3)
[(h6-p-cymene)Ru(L4)Cl]PF6 (4)
[(h6-p-cymene)Ru(L5)Cl]PF6 (5)
[(h6-p-cymene)Ru(L6)Cl]PF6 (6)
[(h6-p-cymene)Ru(L7)Cl]PF6 (7)
[(h6-p-cymene)Ru(L8)Cl]PF6 (8)
[(h6-p-cymene)Ru(L9)Cl]PF6 (9)
[(h6-p-cymene)Ru(L10)Cl]PF6 (10)
Cisplatin
IC50 [mm]
> 100
> 100
> 100
> 100
52.16 2.4
> 100
38.33 2.3
25.21 1.1
14.36 2.4
46.80 3.7
21.30 1.7
[a] IC50 values are drug concentrations necessary for 50 % inhibition of
cell viability. Data are presented as means standard deviations and cell
viability is assessed after 24 h of incubation.
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Interaction with nucleobases
The binding studies of anticancer metallodrugs with model nucleobase 9-ethylguanine (9-EtG) and 9-methyladenine (9-MeA)
provided insights into their intracellular fate.[13] The reactions
of complex 9 with model nucleobase 9-EtG or 9-MeA were
monitored by using the 1H NMR technique. Solutions of complex 9 (ca. 1 mm) and 2.0 molar equivalents of 9-EtG or 9-MeA
in 50 % CD3OD/50 % D2O (v/v) were prepared, and 1H NMR
spectra were recorded at different time intervals at 310 K. According to the 1H NMR spectra at different time intervals, no
additional 1H NMR peaks were observed over a period of 24 h
(Figures S69–S70 in the Supporting Information). These results
suggested that no reaction with model nucleobase occurred
for complex 9. Also, the formation of nucleobase adducts with
these ruthenium(II) complexes were not detected by mass
spectrometry. Thus, DNA may not be the major target for this
type of ruthenium(II) complexes.
Figure 2. Inhibition of the growth of A549 cells by complexes 1–10 and cisplatin.
Substituent perturbations in this system can result in significant variation of anticancer activities. First, the length of the
alkyl substitutions on the imidazole ring showed a significant
effect on the cytotoxicity of complexes. When the tether
length on the imidazole ring increased from methyl to butyl,
the complexes exhibited increased cytotoxicity (complex 6:
> 100 mm vs. complex 9: 14.36 mm). The cytotoxicity followed
the order of butyl > isopropyl > ethyl > methyl-substituted
NHCs. It seems reasonable that, in accordance with the behavior of some previously reported potent anticancer agents,[11]
the increased length of the alkyl substituents may increase the
lipophilicity of these complexes and thus lead to the enhanced
cytotoxicity. Next, maintaining the imidazole ring substituent
unchanged and increasing the size of the ortho substituents
on the aniline gradually, the cytotoxicity also increased and followed the order isopropyl > methyl > H-substituted aniline. For
example, complexes 7, 8, 9, and 10, the IC50 values of which
were 38.33, 25.21, 14.36, and 46.8 mm, respectively, exhibited in
vitro anticancer activity significantly superior to complexes 2
(> 100 mm), 3 (> 100 mm), 4 (> 100 mm), and 5 (52.16 mm) containing the same substituents (R1 and R2) against A549 cancer
cell lines. Finally, the influence of the substituent at the imine
carbon on anticancer activity of this class of complexes was
further investigated. Replacement of the methyl group on the
imine carbon by a more lipophilic phenyl ring led to enhanced
anticancer efficacy (complex 3: IC50 > 100 mm vs. complex 10:
IC50 = 46.8 mm). Pervious work has shown that the lipophilicity
and cytotoxicity of the similar half-sandwich C,N and N,N-chelating iridium(III) complexes increased by the incorporation of
phenyl substituents on h5-C5Me5.[12] In this system, the anticancer activity of such complexes could also be tuned by regulating the lipophilicity of the substituents on the imine carbon.
Overall, small structural changes on three positions of chelating ligand of these complexes can significantly alter their biological properties. These results may guide the development of
the structure–activity relationships (SARs) for ruthenium-based
anticancer agents and provide a rational strategy for improving
their toxicological properties.
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Reaction with NADH
Coenzyme NADH and NAD + play a key role in numerous biocatalyzed processes. Our previous work has reported that halfsandwich iridium(III) and ruthenium(II) anticancer complexes
can oxidize NADH to generate reactive oxygen species (ROS)
H2O2, which provides a pathway for an oxidant mechanism of
action.[8b, 14] To investigate the impact of this family of complexes containing three modifiable potential sites on the catalytic ability, the reactions of complexes 3, 5, 8, 9, and 10 (ca.
1 mm) with NADH (100 mm) in 5 % MeOH/95 % H2O (v/v) were
monitored by employing a ultraviolet/visible (UV/Vis) spectrophotometer at 298 K (Figure 3 a and Figure S71 in the Supporting Information). The conversion of NADH to NAD + was detected by measuring the UV absorption at 339 nm by using a
spectrophotometer, as NADH exhibits an absorption peak at
339 nm whereas NAD + does not. The turnover numbers
(TONs) of complexes 3 (6.0), 5 (8.1), 8 (13.1), 9 (8.5), and 10
(7.8) were calculated by measuring the absorption difference
at 339 nm (Figure 3 b). The size of the ortho substituents on
the aniline moiety, the substituent perturbations on the imine
carbon, and the length of the alkyl substitutions on the imidazole ring appear to exhibit little variation on the catalytic activity of this class of complexes.
Cell cycle arrest
As most metal-based chemotherapeutic agents could disrupt
the regulated cell cycle distribution, the effect of the most
active complex 9 on the cell cycle perturbation in A549 cancer
cells was examined by flow cytometry analysis. As shown in
Figure 4, Figure S72, and Table S3 (in the Supporting Information), after treatment of A549 cells with complex 9 at 0.5, 1,
and 2 equipotent concentrations of IC50 for 24 h, the percentage of cells at the S phase increased markedly from 22.52 % to
33.25 %. Meanwhile, the percentage of the cells at the G0/G1
phase decreased from 64.00 % to 46.82 %. The cells at the G2/M
phase only slightly changed. These results indicated that com4
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Figure 3. (a) UV/Vis spectra of the reaction of NADH (100 mm) with complex 8 (1 mm) in 5 % MeOH/95 % H2O (v/v) at 298 K for 8 h. (b) The turnover numbers
(TONs) of complexes 3, 5, 8, 9, and 10.
Figure 5. Apoptosis analysis of A549 cells after 24 h of exposure to complex 9 at 310 K determined by flow cytometry by using annexin V-FITC vs. PI
staining. Populations for cells in four stages treated by complex 9. Data are
quoted as mean SD of three replicates.
Figure 4. Flow cytometry data for cell cycle distribution of A549 cancer cells
exposed to complex 9 for 24 h. Concentrations used were 0.5, 1, and 2 equipotent concentrations of IC50. Cell staining for flow cytometry was carried
out by using PI/RNase. Data are quoted as mean SD of three replicates.
Mitochondrial membrane potential (MMP)
plex 9 can induce perturbations of cell-cycle progression and
effectively stall cells in the S phase of the cell cycle in a dosedependent manner.
The change of mitochondrial membrane potential (MMP, Dym),
which is a significant indicator of cell health, was detected by
using
5,5’,6,6’-tetrachloro-1,1’-3,3’-tetraethyl-benzimidazolyl
carbocyanine iodide (JC-1) staining and analyzed by using flow
cytometry. JC-1 can be aggregated in mitochondria in a potential-dependent manner indicated by a marked red to green
color shift.[15] Treatment of A549 cells with complex 9 resulted
in a dose-dependent increase in the red fluorescence and decrease in green fluorescence of JC-1 (Figure 6 and Table S5 in
the Supporting Information). After 24 h of treatment, the percentage of cells with mitochondrial membrane depolarization
was 71.35 % at a concentration of 2 IC50, which is elevated
from the vehicle-treated group (10.12 %). In addition, representative JC-1 red/green ratio signals are shown in Figure S74 and
Table S6 (in the Supporting Information). Treatment of A549
cells with complex 9 at concentrations of 2 IC50 values significantly decreased the JC-1 red/green fluorescence ratios (control: 8.94 1.1; 2 IC50 : 0.40 0.1). This observation suggested
that complex 9 can cause cancer cell death through the dysfunction of the mitochondrial membrane potential.
Apoptosis assay
To assess whether these ruthenium(II) complexes induce A549
cell death by apoptosis or necrosis, A549 cells were dualstained with annexin V-FITC/propidium iodide (PI) reagents
and analyzed by flow cytometry. As shown in Figure 5, Figure S73, and Table S4 (in the Supporting Information), upon incubating A549 cells with complex 9 at 0.5, 1, 2, and 3 equipotent concentrations of IC50 for 24 h, a dose-dependent apoptosis population was detected. At a maximum concentration (3
IC50), a total of 82.15 % (early apoptotic + late apoptotic) of
cells were undergoing enhanced apoptosis compared with the
untreated group (6.21 %). In addition, no strikingly increased
necrotic population was detected. These results suggested
that complex 9 can induce A549 cell death through a high incidence of apoptosis, and cell necrotic was not responsible for
A549 cell death.
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Figure 6. Changes in mitochondrial membrane potential of A549 cancer cells induced by complex 9.
ROS determination
24 h with the test agent at concentrations of 0.25 IC50 and
0.5 IC50 (Figure 7 and Figure S75 in the Supporting Information), indicating that complex 9 can result in disruption of mitochondrial function through production of reactive oxygen
species (ROS).
Perturbation of mitochondrial functions, such as the reduction
of mitochondrial membrane potential (MMP), may result in
over-generation of intracellular reactive oxygen species
(ROS).[16] The impact of complex 9 on the number of intracellular ROS was quantified by flow cytometry with 2’,7’-dichlorodihydrofluorescein diacetate (H2DCFDA) staining. The non-fluorescent H2DCFDA can be converted to the highly bright 2’,7’dichlorofluorescein (DCF) by intracellular ROS.[17] Compared
with the untreated group, a dose-dependent trend in the DCF
fluorescence signals was observed after a treatment period of
Lysosomal damage
Lysosomes play important roles in many physiological processes and cell signaling pathways. Acridine orange (AO) as an integrity indicator can be used to evaluate the dysfunction of lysosomes at the subcellular level.[18] AO is a useful probe employed to assess the lysosomal functional state at this level because it emits a concentration-dependent red/green fluorescence.[19] As shown in Figure 8, A549 cells only treated with
acridine orange (5 mm) displayed distinct red fluorescence in lysosomes, indicating that the lysosomes of A549 cells under
such conditions were intact. However, as the agent concentration increased, the red fluorescence of AO gradually decreased,
indicating that lysosomal integrity was jeopardized by treatment with complex 9. Thus, complex 9 can induce cell death
through lysosomal damage.
Conclusion
A series of versatile half-sandwich ruthenium(II) p-cymene complexes, which contained different imine-N-heterocyclic carbene
ligands, were explored as promising anticancer agents. The stability studies revealed that these complexes had sufficient stability for the preparation of samples for biological assays. This
class of ruthenium(II) p-cymene complexes showed anticancer
activity comparable to or even higher than cisplatin toward
Figure 7. Analysis of ROS levels by flow cytometry after A549 cells were
treated with complex 9 at 0.25 and 0.5 equipotent concentrations of IC50 for
24 h and stained with H2DCFDA.
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Figure 8. Observation of lysosomal disruption in A549 cells loaded with complex 9 for 6 h at 37 8C, then stained with acridine orange (5 mm) at 37 8C for
15 min. Emission was collected at 510 20 nm (green) and 625 20 nm (red) upon excitation at 488 nm. Scale bar: 20 mm. The cells were treated with
(a) only acridine orange; (b) acridine orange and complex 9 (1 IC50); (c) acridine orange and complex 9 (3 IC50).
cin mixture, trypsin/EDTA, phosphate-buffered saline (PBS), MTT (3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), PI (propidium iodide), JC-1 (5,5’,6,6’-tetrachloro-1,1’,3,3’-tetraethylbenzimidazolyl carbocyanine iodide), and H2DCFDA (2’,7’-dichlorodihydrofluorescein diacetate) were purchased from Sangon Biotech. Tested
complexes were dissolved in DMSO just before the experiments,
and the concentration of DMSO was 1 % (v/v). 1H and 13C NMR
spectra were recorded in 5 mm NMR tubes at ambient temperature with a Bruker Avance 500 spectrometer or a Bruker Ascend
400 spectrometer using TMS as an internal standard and CDCl3 or
DMSO as solvent. Mass spectra of the L2–L5 and L7–L10 were recorded with a Thermo LTQ Orbitrap XL (ESI + ). Mass spectra of the
complexes 1–10 were recorded with an Atouflex Speed MALDITOF MS. Microanalysis (C, H, and N) was carried out by using a
Carlo Erba model EA 1108 microanalyzer. X-ray diffraction data
were collected at 298(2) K with a Bruker Smart CCD area detector
with graphite-monochromated MoKa radiation (l = 0.71073 ).
CCDC 1848 902 contains the supplementary crystallographic data
for this paper. These data are provided free of charge by The Cambridge Crystallographic Data Centre.
A549 cancer cells. The structure–activity relationship study revealed that the longer length of the alkyl substitutions on the
imidazole ring, the larger size of ortho substituents on the aniline, and more lipophilic substituents on the imine carbon resulted in the higher anticancer activity of these ruthenium(II)
complexes.
No nucleobase binding was detected for complex 9, suggesting that DNA may not be a possible target. This type of
complex gave effective catalysts for transfer hydrogenation
converting coenzyme NADH into NAD + . The effect of substituents in the three positions of the ligands on the catalytic ability seemed to be insignificant. Further mechanistic studies
showed that complex 9 can trigger the arrest of cell growth at
the S phase and efficiently induce early- and late-stage apoptosis in A549 cells. Simultaneously, depolarization of the mitochondrial membrane potential (MMP) and the increase in intracellular levels of the ROS were also observed. Interestingly, lysosomal damage was detected in A549 cancer cells by confocal microscopy, suggesting that these complexes may mediate
cell death through lysosomal damage.
Synthesis and characterizationsSynthesis of the ligands
General method: the imidazole with varying substituents was
added dropwise to a solution of the corresponding iminochloride
in dry THF (20 mL) over a period of 5 min. The mixture was stirred
at ambient temperature for 20 h (L1–L4 and L6–L9) or 4 days (L5
and L10), and the product slowly precipitated as a white solid (L1–
L4 and L6–L9) or yellow solid (L5 and L10). The crude product was
obtained by filtration, washed with dry THF (3 15 mL), and dried
under reduced pressure. The 1H NMR spectra showed the presence
of two geometric isomers (E/Z), which is similar with the compound reported previously.[21c]
[3-Methyl-1-(2,6-dimethylphenyl)iminyl-C3H3N2] + Cl (L1): 1-Methylimidazole (0.86 g, 10.47 mmol) and N-(2,6-dimethylphenyl)acetimidoyl chloride (1.89 g, 10.40 mmol) were used. Yield: 82 % (2.26 g,
8.57 mmol). This ligand is previously known.[21a]
[3-Ethyl-1-(2,6-dimethylphenyl)iminyl-C3H3N2] + Cl (L2): 1-Ethylimidazole (0.69 g, 7.20 mmol) and N-(2,6-dimethylphenyl)acetimidoyl chloride (1.31 g, 7.21 mmol) were used. Yield: 92 % (1.83 g,
6.59 mmol). 1H NMR (400 MHz, CDCl3), isomer 1/isomer 2 = 1:0.37
(molar ratio). Isomer 1: d = 11.82 (s, 1 H, NCHN), 8.24 (s, 1 H, imidazole-H), 7.49 (s, 1 H, imidazole-H), 7.09 (m, 3 H, Ar-H), 4.67 (q, J =
7.3 Hz, 2 H, N-CH2Me), 2.55 (s, 3 H, imine-CH3), 2.02 (s, 6 H, o-Ar-CH3),
1.70 ppm (t, J = 7.3 Hz, 3 H, N-CH2CH3); isomer 2: d = 9.48 (s, 1 H,
NCHN), 7.38 (s, 1 H, imidazole-H), 7.19 (s, 1 H, imidazole-H), 7.04–
Experimental Section
General information
RuCl3·n H2O, a-terpinene, 1-methylimidazole, 1-ethylimidazole, 1isopropylimidazole, 1-butylimidazole, acetyl chloride, benzoyl chloride, aniline, 2,6-dimethylaniline, 2,6-diisopropylaniline, triphosgene, thionyl dichloride, silver(I) oxide, 9-ethylguanine, and 9-methyladenine were purchased from Sigma–Aldrich and used directly as
such. Tetrahydrofuran was dried over sodium/benzophenone for
24 h, and dichloromethane was dried over phosphorus pentoxide
for 8 h before being used. [(h6-p-Cymene)RuCl2]2 was prepared by
using a literature procedure.[20] The intermediate products N-(2,6diisopropylphenyl)acetamide, N-(2,6-dimethylphenyl)acetamide, Nphenylbenzamide, N-(2,6-dimethylphenyl)benzamide, N-(2,6-dimethylphenyl)acetimidoyl chloride, N-(2,6-diisopropylphenyl)acetimidoyl chloride, N-(2,6-dimethylphenyl)benzenecarboximidoyl chloride, and N-phenylbenzenecarboximidoyl chloride were prepared
according to previously reported procedures.[21] The imine-N-heterocyclic carbene ligands L1–L4,[21a] L5,[21b–e] L6–L9,[21a] and L10[21b–e]
were prepared according to slightly modified procedures reported
previously. For the biological experiments, Dulbecco’s Modified
Eagle’s Medium (DMEM), fetal bovine serum, penicillin/streptomyChem. Asian J. 2018, 00, 0 – 0
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[3-Me-1-(2,6-diisopropylphenyl)iminyl-C3H3N2] + Cl (L6): 1-Methylimidazole (0.28 g, 3.41 mmol) and N-(2,6-diisopropylphenyl)acetimidoyl chloride (0.79 g, 3.32 mmol) were used. Yield: 61 % (0.65 g,
2.03 mmol). This ligand is previously known.[21a]
7.00 (m, 3 H, Ar-H), 4.37 (q, J = 7.3 Hz, 2 H, N-CH2Me), 2.28 (s, 3 H,
imine-CH3), 2.24 (s, 6 H, o-Ar-CH3), 1.58 ppm (t, J = 7.3 Hz, 3 H, NCH2CH3); 13C NMR (101 MHz, CDCl3): d = 173.16, 169.33, 143.19,
135.76 (NCHN), 134.65 (NCHN), 134.46, 128.56, 128.35, 127.99,
127.13, 126.14, 124.83, 122.18, 120.38, 119.94, 117.97, 45.98, 44.69,
23.08, 18.46, 17.98, 16.47, 15.64, 15.55 ppm; ESI-MS (m/z): calcd for
C15H20N3 : 242.16572; found: 242.16255, [3-Et-1-(2,6-dimethylphenyl)iminyl-C3H3N2] + .
[3-iPr-1-(2,6-dimethylphenyl)iminyl-C3H3N2] + Cl (L3): 1-Isopropylimidazole (0.43 g, 3.90 mmol) and N-(2,6-dimethylphenyl)acetimidoyl chloride (0.70 g, 3.85 mmol) were used. Yield: 85 % (0.96 g,
3.29 mmol). 1H NMR (500 MHz, CDCl3), isomer 1/isomer 2 = 1:0.81
(molar ratio). Isomer 1: d = 11.95 (s, 1 H, NCHN), 8.25 (s, 1 H, imidazole-H), 7.45 (s, 1 H, imidazole-H), 7.08 (d, J = 3.4 Hz, 2 H, Ar-H),
7.04–6.98 (m, 1 H, Ar-H), 5.34–5.23 (m, 1 H, iPr-CH3), 2.59 (s, 3 H,
imine-CH3), 2.03 (s, 6 H, o-Ar-CH3), 1.72 ppm (d, J = 6.5 Hz, 6 H, N-iPrCH3); isomer 2: d = 9.37 (s, 1 H, NCHN), 7.38 (s, 1 H, imidazole-H),
7.21 (s, 1 H, imidazole-H), 7.18–7.05 (m, 3 H, Ar-H), 4.84–4.76 (m, 1 H,
iPr-CH3), 2.28 (s, 3 H, imine-CH3), 2.24 (s, 6 H, o-Ar-CH3), 1.61 ppm (d,
J = 6.5 Hz, 6 H, N-iPr-CH3); 13C NMR (101 MHz, CDCl3): d = 173.16,
169.25, 143.24, 137.29, 135.76 (NCHN), 133.72 (NCHN), 128.57,
128.35, 128.02, 127.16, 126.18, 124.81, 120.12, 119.83, 118.46,
118.15, 54.24, 52.62, 23.18, 23.01, 18.47, 18.44, 18.00, 16.64 ppm;
ESI-MS (m/z): calcd for C16H22N3 : 256.18137; found: 256.17816, [3iPr-1-(2,6- dimethylphenyl)iminyl-C3H3N2] + .
[3-Et-1-(2,6-diisopropylphenyl)iminyl-C3H3N2] + Cl (L7): 1-Ethylimidazole (0.32 g, 3.33 mmol) and N-(2,6-diisopropylphenyl)acetimidoyl chloride (0.80 g, 3.36 mmol) were used. Yield: 68 % (0.75 g,
2.25 mmol). 1H NMR (500 MHz, CDCl3), isomer 1/isomer 2 = 1:0.68
(molar ratio). Isomer 1: d = 11.97 (s, 1 H, NCHN), 8.22 (s, 1 H, imidazole-H), 7.57 (s, 1 H, imidazole-H), 7.18 (s, 3 H, Ar-H), 4.69 (q, J =
6.6 Hz, 2 H, N-CH2Me), 2.68–2.59 (m, 2 H, iPr-CH), 2.56 (s, 3 H, imineCH3), 1.71 (t, J = 6.6 Hz, 3 H, N-CH2CH3), 1.17 (d, J = 6.8 Hz, 6 H, iPrCH3), 1.12 ppm (d, J = 6.1 Hz, 6 H, iPr-CH3); isomer 2: d = 9.55 (s, 1 H,
NCHN), 7.36 (s, 1 H, imidazole-H), 7.23 (s, 1 H, imidazole-H), 7.21–
7.16 (m, 3 H, Ar-H), 4.40 (q, J = 6.6 Hz, 2 H, N-CH2Me), 3.22–3.08 (m,
2 H, iPr-CH), 2.26 (s, 3 H, imine-CH3), 1.59 (t, J = 6.6 Hz, 3 H, NCH2CH3), 1.25–1.19 ppm (dd, J = 6.8 Hz, 7.8 Hz, 12 H, iPr-CH3);
13
C NMR (101 MHz, CDCl3): d = 173.59, 170.05, 146.85, 146.49,
136.50 (NCHN), 134.87 (NCHN), 129.08, 128.32, 125.50, 123.92,
123.53, 123.41, 122.08, 120.21, 119.95, 117.78, 44.75, 28.75, 28.50,
24.41, 23.67, 23.21, 22.84, 15.72 ppm; ESI-MS (m/z): calcd for
C19H28N3 : 298.22832; found: 298.22723, [3-Et-1-(2,6-diisopropylphenyl)iminyl-C3H3N2] + .
[3-iPr-1-(2,6-diisopropylphenyl)iminyl-C3H3N2] + Cl (L8): 1-Isopropylimidazole (0.39 g, 3.54 mmol) and N-(2,6-diisopropylphenyl)acetimidoyl chloride (0.83 g, 3.49 mmol) were used. Yield: 63 % (0.77 g,
2.21 mmol). 1H NMR (500 MHz, CDCl3), isomer 1/isomer 2 = 1:0.2
(molar ratio). Isomer 1: d = 12.08 (s, 1 H, NCHN), 8.23 (s, 1 H, imidazole-H), 7.51 (s, 1 H, imidazole-H), 7.18 (s, 3 H, Ar-H), 5.41–5.29 (m,
1 H, iPr-CH), 2.67–2.61 (m, 2 H, iPr-CH), 2.61 (s, 3 H, imine-CH3), 1.73
(d, J = 6.6 Hz, 6 H, iPr-CH3), 1.17 (d, J = 6.8 Hz, 6 H, iPr-CH3),
1.12 ppm (d, J = 6.8 Hz, 6 H, iPr-CH3); isomer 2: d = 9.29 (s, 1 H,
NCHN), 7.40 (s, 1 H, imidazole-H), 7.24 (s, 1 H, imidazole-H), 7.21–
7.10 (s, 3 H, Ar-H), 4.83–4.75 (m, 1 H, iPr-CH), 3.22–3.07 (m, 2 H, iPrCH), 2.26 (s, 3 H, imine-CH3), 1.61 (d, J = 6.6 Hz, 6 H, iPr-CH3), 1.25–
1.19 ppm (dd, J = 6.8 Hz, 7.6 Hz, 12 H, iPr-CH3); 13C NMR (101 MHz,
CDCl3): d = 173.60, 170.15, 140.70, 137.51 (NCHN), 136.50 (NCHN),
133.69, 128.26, 125.46, 123.92, 123.50, 123.36, 120.10, 119.96,
118.47, 117.94, 54.25, 52.63, 28.72, 28.46, 24.41, 23.68, 23.21, 23.07,
22.82, 17.06 ppm; ESI-MS (m/z): calcd for C20H30N3 : 312.24397;
found: 312.24039, [3-iPr-1-(2,6-diisopropylphenyl)iminyl-C3H3N2] + .
[3-nBu-1-(2,6-dimethylphenyl)iminyl-C3H3N2] + Cl (L4): 1-Butylimidazole (0.48 g, 3.87 mmol) and N-(2,6-dimethylphenyl)acetimidoyl
chloride (0.70 g, 3.85 mmol) were used. Yield: 79 % (0.93 g,
3.04 mmol). 1H NMR (500 MHz, CDCl3), isomer 1/isomer 2 = 1:0.52
(molar ratio). Isomer 1: d = 12.02 (s, 1 H, NCHN), 8.23 (s, 1 H, imidazole-H), 7.39 (s, 1 H, imidazole-H), 7.07 (d, J = 9.4 Hz, 2 H, Ar-H),
7.05–6.97 (m, 1 H, Ar-H), 4.59 (t, J = 6.3 Hz, 2 H, nBu-CH2), 2.55 (s,
3 H, imine-CH3), 2.02 (s, 6 H, o-Ar-CH3), 2.07–1.97 (m, 2 H, nBu-CH2),
1.50–1.46 (dq, J = 14.3, 7.2 Hz, 2 H, nBu-CH2), 1.01 ppm (t, J = 7.2 Hz,
3 H, nBu-CH3); isomer 2: d = 9.38 (s, 1 H, NCHN), 7.37 (s, 1 H, imidazole-H), 7.18–7.12 (m, 2 H, imidazole-H and Ar-H), 7.04–7.01 (d, J =
9.4 Hz, 2 H, Ar-H), 4.29 (t, J = 6.3 Hz, 2 H, nBu-CH2), 2.28 (s, 3 H,
imine-CH3), 2.24 (s, 6 H, o-Ar-CH3), 1.89–1.86 (m, 2 H, nBu-CH2), 1.41–
1.33 (dq, J = 14.3, 7.2 Hz, 2 H, nBu-CH2), 0.97 ppm (t, J = 7.2 Hz, 3 H,
nBu-CH3); 13C NMR (101 MHz, CDCl3): d = 173.13, 169.35, 143.18,
135.78 (NCHN), 134.92 (NCHN), 134.53, 128.56, 128.36, 127.98,
127.08, 126.14, 124.84, 122.44, 120.67, 119.87, 117.88, 50.46, 49.34,
32.20, 32.06, 23.08, 19.53, 19.39, 18.48, 18.00, 16.53, 13.48,
13.38 ppm; ESI-MS (m/z): calcd for C17H24N3 : 270.19702; found:
270.19351, [3-nBu-1-(2,6-dimethylphenyl)iminyl-C3H3N2] + .
[3-nBu-1-(2,6-diisopropylphenyl)iminyl-C3H3N2] + Cl (L9): 1-Butylimidazole (0.42 g, 3.38 mmol) and N-(2,6-diisopropylphenyl)acetimidoyl chloride (0.80 g, 3.36 mmol) was used. Yield: 49 % (0.60 g,
1.66 mmol). 1H NMR (500 MHz, CDCl3), isomer 1/isomer 2 = 1:1.35
(molar ratio). Isomer 1: d = 12.00 (s, 1 H, NCHN), 8.21 (s, 1 H, imidazole-H), 7.50 (s, 1 H, imidazole-H), 7.19–7.17 (s, 3 H, Ar-H), 4.61 (t, J =
7.2 Hz, 2 H, nBu-CH2), 2.68–2.58 (m, 2 H, iPr-CH), 2.56 (s, 3 H, imineCH3), 2.08–1.98 (m, 2 H, nBu-CH2), 1.48 (dq, J = 15.0, 7.5 Hz, 2 H,
nBu-CH2), 1.16 (d, J = 6.6 Hz, 6 H, iPr-CH3), 1.11 (d, J = 6.6 Hz, 6 H, iPrCH3), 1.03–0.99 ppm (t, J = 7.4 Hz, 3 H, nBu-CH3); isomer 2: d = 9.48
(s, 1 H, NCHN), 7.46–7.32 (s, 1 H, imidazole-H), 7.29 (s, 1 H, imidazole-H), 7.28–7.20 (s, 3 H, Ar-H), 4.32 (t, J = 7.2 Hz, 2 H, nBu-CH2),
3.21–3.08 (m, 2 H, iPr-CH), 2.26 (s, 3 H, imine-CH3), 1.93–1.85 (m, 2 H,
nBu-CH2), 1.40–1.32 (dq, J = 15.0, 7.5 Hz, 2 H, nBu-CH2), 1.26–1.18
(m, 12 H, iPr-CH3), 0.97 ppm (t, J = 7.4 Hz, 3 H, nBu-CH3); 13C NMR
(101 MHz, CDCl3): d = 169.98, 146.86, 146.48, 136.51 (NCHN), 135.15
(NCHN), 131.48, 129.08, 128.33, 125.51, 123.93, 123.53, 123.42,
120.47, 119.96, 117.68, 50.57, 49.40, 32.24, 28.76, 28.50, 24.42,
23.67, 23.24, 22.74, 19.60, 19.42, 17.02, 13.40 ppm; ESI-MS(m/z):
calcd for C21H32N3 : 326.25962; found: 326.25842, [3-nBu-1-(2,6-diisopropylphenyl)iminyl-C3H3N2] + .
(L5): 1-Isopropylimidazole
[3-iPr-1-{C(C6H5)N(C6H5)}C3H3N2] + Cl
(1.14 g, 10.35 mmol) and N-phenylbenzenecarboximidoyl chloride
(2.23 g, 10.34 mmol) were used. Yield: 85 % (2.88 g, 8.84 mmol).
1
H NMR (500 MHz, CDCl3), isomer 1/isomer 2 = 1:0.78 (molar ratio).
Isomer 1: d = 9.14 (s, 1 H, NCHN), 7.89 (m, 2 H, imidazole-H), 7.44
(m, 1 H, Ar-H), 7.40 (m, 1 H, Ar-H), 7.30 (t, J = 7.6 Hz, 2 H, Ar-H),
7.21–7.19 (d, J = 2.7 Hz, 3 H, Ar-H), 6.93 (d, J = 2.7 Hz, 3 H, Ar-H),
4.79–4.68 (m, 1 H, iPr-CH3), 1.62 ppm (d, J = 6.6 Hz, 6 H, N-iPr-CH3);
isomer 2: d = 12.91 (s, 1 H, NCHN), 7.67 (d, J = 6.0 Hz, 2 H, imidazole-H), 7.58–7.52 (m, 1 H, Ar-H), 7.51–7.48 (m, 2 H, Ar-H), 7.39–7.36
(m, 2 H, Ar-H), 7.19–7.14 (m, 5 H, Ar-H), 3.80–3.68 (m, 1 H, iPr-CH3),
1.73 ppm (d, J = 6.6 Hz, 6 H, N-iPr-CH3); 13C NMR (101 MHz, CDCl3):
d = 171.05, 165.90, 138.18, 134.92 (NCHN), 133.85 (NCHN), 132.06,
131.78, 129.83, 129.52, 129.27, 129.04, 128.99, 128.70, 127.40,
127.28, 125.62, 124.95, 124.44, 121.37, 120.49, 120.17, 118.22, 54.19,
52.64, 23.18, 22.88 ppm; ESI-MS(m/z): calcd for C19H20N3 :
290.16572; found: 290.16464, [3-iPr-1-{C(C6H5)N(C6H5)}C3H3N2] + .
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[3-iPr-1-{C(C6H5)N(2,6-Me2C6H3)}C3H3N2] + Cl (L10): 1-Isopropylimidazole (1.05 g, 9.53 mmol) and N-(2,6-dimethylphenyl)benzenecarboximidoyl chloride (2.12 g, 8.70 mmol) were used. Yield: 72 %
(2.23 g, 6.30 mmol). 1H NMR (500 MHz, CDCl3), isomer 1/isomer 2 =
1:0.66 (molar ratio). Isomer 1: d = 10.46 (s, 1 H, NCHN), 7.94 (s, 2 H,
imidazole-H), 7.50–7.47 (m, 1 H, Ar-H), 7.40 (q, J = 8.0 Hz, 4 H, Ar-H),
6.91 (dt, J = 8.9, 5.7 Hz, 3 H, Ar-H), 5.54 (m, 1 H, iPr-CH), 2.05 (s, 6 H,
o-Ar-CH3), 1.69 ppm (d, J = 6.6 Hz, 6 H, iPr-CH3); isomer 2: d = 9.41
(s, 1 H, NCHN), 8.00 (d, J = 7.3 Hz, 2 H, imidazole-H), 7.98–7.96 (m,
1 H, Ar-H), 7.76 (d, J = 6.0 Hz, 2 H, Ar-H), 7.58–7.47 (m, 2 H, Ar-H),
7.35 (s, 2 H, Ar-H), 7.29 (s, 1 H, Ar-H), 4.95–4.87 (m, 1 H, iPr-CH), 2.30
(s, 6 H, o-Ar-CH3), 1.58 ppm (d, J = 6.6 Hz, 6 H, iPr-CH3); 13C NMR
(101 MHz, CDCl3): d = 172.50, 166.07, 148.18, 143.25, 136.31
(NCHN), 135.80 (NCHN), 134.40, 134.24, 133.77, 132.43, 131.72,
129.36, 128.83, 128.66, 128.17, 127.44, 127.28, 126.39, 124.72,
120.70, 120.12, 118.31, 54.14, 52.52, 23.20, 22.88, 18.51, 18.47 ppm;
ESI-MS(m/z): calcd for C21H24N3 : 318.19702; found: 318.19586, [3iPr-1-{C(C6H5)N(2,6-Me2C6H3)}C3H3N2] + .
20.11, 19.18, 17.95, 15.46, 15.01 ppm; ESI-MS (m/z): calcd for
C25H33ClN3Ru: 512.141; found: 511.907, [(h6-p-cymene)Ru(L2)Cl] + ; elemental analysis calcd (%) for C25H33N3ClRuPF6 : C 45.70, H 5.06, N
6.40; found: C 45.86, H 5.11, N 6.39.
[(h6-p-cymene)Ru(L3)Cl]PF6 (3): Yield: 58.4 mg (87 %). 1H NMR
(500 MHz, CDCl3): d = 7.62 (d, J = 2.3 Hz, 1 H, imidazole-H), 7.31 (d,
J = 2.3 Hz, 1 H, imidazole-H), 7.24 (dd, J = 8.6, 4.5 Hz, 3 H, Ar-H), 5.58
(d, J = 6.2 Hz, 1 H, p-cymene-H), 5.30 (d, J = 6.0 Hz, 1 H, p-cymeneH), 5.04–4.93 (m, 2 H, p-cymene-H and N-CH-iPr2), 4.91 (d, J = 6.0 Hz,
1 H, p-cymene-H), 2.64–2.56 (m, 1 H, p-cymene-CH-iPr2), 2.38 (s, 3 H,
o-aniline-CH3), 2.33 (s, 3 H, o-aniline-CH3), 2.22 (s, 3 H, imine-CH3),
2.08 (s, 3 H, p-cymene-CH3), 1.79 (d, J = 6.8 Hz, 3 H, N-CH3-iPr), 1.56
(d, J = 6.6 Hz, 3 H, N-CH3-iPr), 1.18 (d, J = 7.0 Hz, 3 H, p-cymene-CH3iPr), 1.14 ppm (d, J = 6.8 Hz, 3 H, p-cymene-CH3-iPr); 13C NMR
(101 MHz, CDCl3): d = 186.85 (NHC carbon-Ru), 163.63, 146.78,
132.45, 129.93, 129.30, 129.00, 128.23, 120.25, 119.21, 112.95, 90.49,
87.24, 85.43, 84.80, 54.39, 31.45, 23.82, 23.67, 22.96, 21.81, 20.12,
19.28, 17.97, 15.02 ppm; ESI-MS (m/z): calcd for C26H35ClN3Ru:
526.156; found: 526.1267, [(h6-p-cymene)Ru(L3)Cl] + ; elemental
analysis calcd (%) for C26H35N3ClRuPF6 : C 46.53, H 5.26, N 6.26;
found: C 46.39, H 5.31, N 6.50.
Synthesis of the complexes
General method: The imidazolium salt L (0.10 mmol) was dissolved in dry dichloromethane (15.0 mL) and the solution was
added to a round-bottomed flask containing a stirrer. Ag2O
(0.12 mmol) was then added and the reaction mixture stirred in
the absence of light for 6 h. The mixture was filtered through
Celite to remove excess Ag2O. The filtrate was transferred to another round-bottomed flask, which was charged with [(h6-p-cymene)RuCl2]2 (0.05 mmol) and the mixture was stirred at ambient temperature overnight. KPF6 (0.60 mmol) was added with stirring and further stirred for 30 min at ambient temperature. The crude product
was filtered and the solvent was removed under reduced pressure.
The resulting solid was recrystallized by diffusion at room temperature.
[(h6-p-cymene)Ru(L4)Cl]PF6 (4): Yield: 50.0 mg (73 %). 1H NMR
(400 MHz, CDCl3): d = 7.56 (s, 1 H, imidazole-H), 7.25 (s, 4 H, imidazole-H and Ar-H), 5.50 (d, J = 5.9 Hz, 1 H, p-cymene-H), 5.33 (d, J =
5.5 Hz, 1 H, p-cymene-H), 4.91 (dd, J = 10.8, 6.4 Hz, 2 H, p-cymeneH), 4.50–4.37 (m, 2 H, nBu-CH2), 2.68–2.59 (m, 1 H, p-cymene-CHiPr2), 2.39 (s, 3 H, o-aniline-CH3), 2.34 (s, 3 H, o-aniline-CH3), 2.24 (s,
3 H, imine-CH3), 2.09 (s, 3 H, p-cymene-CH3), 2.04–1.98 (m, 2 H, nBuCH2), 1.53–1.46 (m, 2 H, nBu-CH2), 1.18 (d, J = 6.9 Hz, 3 H, p-cymeneCH3-iPr), 1.14 (d, J = 6.8 Hz, 3 H, p-cymene-CH3-iPr), 1.04 ppm (t, J =
7.5 Hz, 3 H, nBu-CH3); 13C NMR (101 MHz, CDCl3): d = 187.86 (NHC
carbon-Ru), 163.68, 146.79, 132.39, 129.91, 129.31, 129.02, 128.23,
123.96, 118.42, 113.24, 105.62, 90.79, 87.20, 85.18, 84.95, 51.59,
31.79, 31.46, 23.76, 21.59, 20.14, 19.98, 19.18, 17.99, 15.01,
13.77 ppm; ESI-MS (m/z): calcd for C27H37ClN3Ru: 540.172; found:
539.978, [(h6-p-cymene)Ru(L4)Cl] + ; elemental analysis calcd (%) for
C27H37N3ClRuPF6 : C 47.34, H 5.44, N 6.13; found: C 47.56, H 5.31, N
6.19.
[(h6-p-Cymene)Ru(L5)Cl]PF6 (5): Yield: 39.5 mg (56 %). 1H NMR
(500 MHz, DMSO): d = 7.99 (d, J = 2.4 Hz, 1 H, imidazole-H), 7.52 (dd,
J = 13.7, 4.8 Hz, 4 H, imidazole-H and Ar-H), 7.39 (s, 4 H, Ar-H), 7.29
(t, J = 8.3 Hz, 3 H, Ar-H), 6.01 (d, J = 6.1 Hz, 1 H, p-cymene-H), 5.52
(d, J = 6.1 Hz, 1 H, p-cymene-H), 5.47 (d, J = 6.2 Hz, 1 H, p-cymeneH), 5.42 (d, J = 6.1 Hz, 1 H, p-cymene-H), 5.08–4.99 (m, 1 H, N-CHiPr2), 2.57–2.52 (m, 1 H, p-cymene-CH-iPr2), 2.11 (s, 3 H, p-cymeneCH3), 1.75 (d, J = 6.7 Hz, 3 H, N-CH3-iPr), 1.45 (d, J = 6.6 Hz, 3 H, NCH3-iPr), 1.04 (d, J = 6.9 Hz, 3 H, p-cymene-CH3-iPr), 1.02 ppm (d, J =
6.9 Hz, 3 H, p-cymene-CH3-iPr); 13C NMR (101 MHz, DMSO): d =
188.86 (NHC carbon-Ru), 162.47, 150.11, 132.46, 129.75, 129.65,
129.60, 128.10, 125.81, 123.83, 123.69, 121.76, 120.83, 107.57,
92.39, 89.07, 88.19, 85.00, 54.32, 31.37, 23.73, 22.93, 22.70, 22.55,
19.14 ppm; ESI-MS (m/z): calcd for C29H33ClN3Ru: 560.141; found:
559.984, [(h6-p-cymene)Ru(L5)Cl] + ; elemental analysis calcd (%) for
C29H33N3ClRuPF6 : C 49.40, H 4.72, N 5.96; found: C 48.99, H 4.81, N
5.73.
[(h6-p-Cymene)Ru(L1)Cl]PF6 (1): Yield: 42.4 mg (66 %). 1H NMR
(500 MHz, CDCl3): d = 7.54 (s, 1 H, imidazole-H), 7.29 (d, J = 5.2 Hz,
1 H, imidazole-H), 7.24 (dd, J = 8.7, 4.0 Hz, 3 H, Ar-H), 5.67 (d, J =
5.4 Hz, 1 H, p-cymene-H), 5.33 (d, J = 6.1 Hz, 1 H, p-cymene-H), 4.98
(d, J = 6.2 Hz, 1 H, p-cymene-H), 4.87 (d, J = 6.1 Hz, 1 H, p-cymeneH), 4.15 (s, 3 H, N-CH3), 2.63–2.54 (m, 1 H, p-cymene-CH-iPr2), 2.38 (s,
3 H, o-aniline-CH3), 2.34 (s, 3 H, o-aniline-CH3), 2.24 (s, 3 H, imineCH3), 2.07 (s, 3 H, p-cymene-CH3), 1.18 (d, J = 7.0 Hz, 3 H, p-cymeneCH3-iPr), 1.14 ppm (d, J = 6.8 Hz, 3 H, p-cymene-CH3-iPr); 13C NMR
(101 MHz, CDCl3): d = 189.03 (NHC carbon-Ru), 163.73, 146.76,
132.40, 129.93, 129.13, 128.99, 128.20, 126.11, 118.07, 112.24,
106.90, 91.20, 86.85, 85.27, 84.98, 38.61, 31.57, 23.88, 21.65, 20.06,
19.23, 17.94, 14.97 ppm; ESI-MS (m/z): calcd for C24H31ClN3Ru:
498.046; found: 497.903, [(h6-p-cymene)Ru(L1)Cl] + ; elemental analysis calcd (%) for C24H31N3ClRuPF6 : C 44.83, H 4.86, N 6.53; found: C
44.99, H 4.71, N 6.69.
[(h6-p-Cymene)Ru(L2)Cl]PF6 (2): Yield: 38.1 mg (58 %). 1H NMR
(500 MHz, CDCl3): d = 7.60 (d, J = 2.3 Hz, 1 H, imidazole-H), 7.33 (d,
J = 2.3 Hz, 1 H, imidazole-H), 7.29–7.26 (m, 1 H, Ar-H), 7.25–7.22 (m,
2 H, Ar-H), 5.66 (d, J = 6.2 Hz, 1 H, p-cymene-H), 5.31 (d, J = 6.1 Hz,
1 H, p-cymene-H), 4.98 (d, J = 6.2 Hz, 1 H, p-cymene-H), 4.88 (d, J =
6.1 Hz, 1 H, p-cymene-H), 4.51 (q, J = 7.4 Hz, 2 H, N-CH2Me), 2.65–
2.54 (m, 1 H, p-cymene-CH-iPr2), 2.38 (s, 3 H, o-aniline-CH3), 2.34 (s,
3 H, o-aniline-CH3), 2.22 (s, 3 H, imine-CH3), 2.05 (s, 3 H, p-cymeneCH3), 1.64 (t, J = 7.3 Hz, 3 H, N-CH2CH3), 1.16 (d, J = 7.0 Hz, 3 H, pcymene-CH3-iPr), 1.13 ppm (d, J = 6.8 Hz, 3 H, p-cymene-CH3-iPr);
13
C NMR (101 MHz, CDCl3): d = 188.00 (NHC carbon-Ru), 163.62,
146.78, 132.41, 129.94, 129.17, 129.00, 128.22, 123.45, 118.58,
112.66, 106.25, 91.03, 87.06, 85.14, 85.10, 46.88, 31.51, 23.79, 21.71,
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[(h6-p-Cymene)Ru(L6)Cl]PF6 (6): Yield: 56.6 mg (81 %). 1H NMR
(500 MHz, CDCl3): d = 7.54 (d, J = 1.9 Hz, 1 H, imidazole-H), 7.44 (t,
J = 7.7 Hz, 1 H, imidazole-H), 7.39–7.35 (m, 1 H, Ar-H), 7.35–7.30 (m,
2 H, Ar-H), 5.97 (d, J = 6.3 Hz, 1 H, p-cymene-H), 5.21 (d, J = 6.0 Hz,
1 H, p-cymene-H), 5.05 (d, J = 6.2 Hz, 1 H, p-cymene-H), 5.02 (d, J =
6.1 Hz, 1 H, p-cymene-H), 4.16 (s, 3 H, N-CH3), 3.54–3.45 (m, 1 H, oaniline-CH-iPr2), 2.55–2.43 (m, 2 H, o-aniline-CH-iPr2 and p-cymeneCH-iPr2), 2.42 (s, 3 H, p-cymene-CH3), 2.25 (s, 3 H, imine-CH3), 1.45 (d,
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J = 6.7 Hz, 3 H, o-aniline-CH3-iPr2), 1.26 (d, J = 6.6 Hz, 3 H, o-anilineCH3-iPr2), 1.17 (d, J = 7.0 Hz, 3 H, p-cymene-CH3-iPr), 1.15 (d, J =
6.6 Hz, 3 H, o-aniline-CH3-iPr2), 1.13 (d, J = 6.9 Hz, 3 H, p-cymeneCH3-iPr), 0.95 ppm (d, J = 6.8 Hz, 3 H, o-aniline-CH3-iPr2); 13C NMR
(101 MHz, CDCl3): d = 188.57 (NHC carbon-Ru), 164.16, 143.86,
143.06, 140.25, 129.07, 126.37, 125.78, 124.81, 118.19, 111.27,
109.07, 90.40, 86.46, 85.96, 82.64, 38.72, 31.04, 27.84, 27.69, 25.75,
25.07, 23.99, 23.83, 22.16, 19.14, 17.29 ppm; ESI-MS (m/z): calcd for
C28H39ClN3Ru: 554.188; found: 554.019, [(h6-p-cymene)Ru(L6)Cl] + ;
elemental analysis calcd (%) for C28H39N3ClRuPF6 : C 48.10, H 5.62, N
6.01; found: C 48.32, H 5.51, N 6.09.
CH3-iPr), 1.02 (t, J = 7.3 Hz, 3 H, nBu-CH3), 0.94 ppm (d, J = 6.8 Hz,
3 H, o-aniline-CH3-iPr2); 13C NMR (101 MHz, CDCl3): d = 187.46 (NHC
carbon-Ru), 164.14, 143.87, 143.04, 140.33, 129.10, 125.82, 124.83,
124.15, 118.53, 110.43, 109.51, 90.28, 86.77, 85.79, 82.66, 51.60,
31.61, 31.00, 27.85, 27.70, 25.80, 25.10, 25.04, 23.89, 23.80, 22.29,
19.95, 19.09, 17.37, 13.78 ppm; ESI-MS (m/z): calcd for
C31H45ClN3Ru: 596.235; found: 596.2108, [(h6-p-cymene)Ru(L9)Cl] + ;
elemental analysis calcd (%) for C31H45N3ClRuPF6 : C 50.23, H 6.12, N
5.67; found: C 50.38, H 6.21, N 5.54. Crystals of complex 9 qualified
for X-ray analysis were obtained by slow diffusion of petroleum
ether into a concentrated solution of complex 9 in ethyl acetate.
[(h6-p-Cymene)Ru(L7)Cl]PF6 (7): Yield: 53.5 mg (75 %). 1H NMR
(500 MHz, CDCl3): d = 7.60 (s, 1 H, imidazole-H), 7.43 (t, J = 7.7 Hz,
1 H, imidazole-H), 7.36 (d, J = 6.9 Hz, 2 H, Ar-H), 7.34 (d, J = 7.7 Hz,
1 H, Ar-H), 5.95 (d, J = 6.3 Hz, 1 H, p-cymene-H), 5.20 (d, J = 6.0 Hz,
1 H, p-cymene-H), 5.04 (t, J = 5.6 Hz, 2 H, p-cymene-H), 4.60–4.47 (q,
J = 7.2 Hz, 2 H, N-CH2Me), 3.55–3.45 (m, 1 H, o-aniline-CH-iPr2), 2.56–
2.43 (m, 2 H, o-aniline-CH-iPr2 and p-cymene-CH-iPr2), 2.42 (s, 3 H, pcymene-CH3), 2.24 (s, 3 H, imine-CH3), 1.64 (t, J = 7.3 Hz, 3 H, NCH2CH3), 1.45 (d, J = 6.7 Hz, 3 H, o-aniline-CH3-iPr2), 1.25 (d, J =
6.6 Hz, 3 H, o-aniline-CH3-iPr2), 1.16 (d, J = 7.0 Hz, 3 H, p-cymeneCH3-iPr), 1.14 (d, J = 6.6 Hz, 3 H, o-aniline-CH3-iPr2), 1.11 (d, J =
6.8 Hz, 3 H, p-cymene-CH3-iPr), 0.94 ppm (d, J = 6.8 Hz, 3 H, o-aniline-CH3-iPr2); 13C NMR (101 MHz, CDCl3): d = 187.60 (NHC carbonRu), 164.10, 143.87, 143.05, 140.23, 129.09, 125.80, 124.81, 123.61,
118.73, 110.81, 109.16, 90.41, 86.67, 85.85, 82.73, 46.92, 31.03,
27.85, 27.68, 25.74, 25.07, 23.85, 22.34, 19.07, 17.39, 15.31 ppm;
ESI-MS (m/z): calcd for C29H41ClN3Ru: 568.203; found: 568.008, [(h6p-cymene)Ru(L7)Cl] + ;
elemental
analysis
calcd
(%)
for
C29H41N3ClRuPF6 : C 48.84, H 5.79, N 5.89; found: C 48.89, H 5.82, N
5.95.
[(h6-p-Cymene)Ru(L8)Cl]PF6 (8): Yield: 43.6 mg (60 %). 1H NMR
(500 MHz, CDCl3): d = 7.69 (s, 1 H, imidazole-H), 7.44 (t, J = 7.7 Hz,
1 H, imidazole-H), 7.41–7.30 (m, 3 H, Ar-H), 5.88 (d, J = 5.8 Hz, 1 H, pcymene-H), 5.19 (d, J = 6.0 Hz, 1 H, p-cymene-H), 5.07 (d, J = 6.0 Hz,
1 H, p-cymene-H), 5.05 (d, J = 5.9 Hz, 1 H, p-cymene-H), 5.01–4.92
(m, 1 H, N-CH-iPr2), 3.54–3.47 (m, 1 H, o-aniline-CH-iPr2), 2.53–2.48
(m, 2 H, o-aniline-CH-iPr2 and p-cymene-CH-iPr2), 2.43 (s, 3 H, pcymene-CH3), 2.25 (s, 3 H, imine-CH3), 1.81 (d, J = 6.6 Hz, 3 H, N-CH3iPr), 1.56 (d, J = 6.4 Hz, 3 H, o-aniline-CH3-iPr2), 1.45 (d, J = 6.5 Hz,
3 H, N-CH3-iPr), 1.25 (d, J = 6.6 Hz, 3 H, o-aniline-CH3-iPr2), 1.18 (d,
J = 6.6 Hz, 3 H, p-cymene-CH3-iPr), 1.15 (d, J = 6.4 Hz, 3 H, o-anilineCH3-iPr2), 1.12 (d, J = 6.8 Hz, 3 H, p-cymene-CH3-iPr), 0.94 ppm (d,
J = 6.8 Hz, 3 H, o-aniline-CH3-iPr2); 13C NMR (101 MHz, CDCl3): d =
186.34 (NHC carbon-Ru), 164.09, 143.87, 143.09, 140.35, 129.09,
125.80, 124.82, 120.53, 119.31, 110.90, 109.14, 89.75, 86.92, 86.46,
82.10, 54.42, 30.91, 27.83, 27.67, 25.76, 25.09, 23.96, 23.84, 22.59,
22.50, 19.16, 17.42 ppm; ESI-MS (m/z): calcd for C30H43ClN3Ru:
582.219; found: 582.42, [(h6-p-cymene)Ru(L8)Cl] + ; elemental analysis calcd (%) for C30H43N3ClRuPF6 : C 49.55, H 5.96, N 5.78; found: C
49.35, H 5.81, N 5.88.
[(h6-p-Cymene)Ru(L10)Cl]PF6 (10): Yield: 47.7 mg (65 %). 1H NMR
(500 MHz, DMSO): d = 8.01 (d, J = 2.4 Hz, 1 H, imidazole-H), 7.59 (d,
J = 2.4 Hz, 2 H, imidazole-H and Ar-H), 7.55 (t, J = 7.4 Hz, 1 H, Ar-H),
7.43 (s, 2 H, Ar-H), 7.24 (d, J = 7.4 Hz, 1 H, Ar-H), 7.14 (t, J = 7.6 Hz,
1 H, Ar-H), 6.96 (d, J = 7.5 Hz, 2 H, Ar-H), 6.13 (d, J = 6.3 Hz, 1 H, pcymene-H), 5.28 (d, J = 6.0 Hz, 1 H, p-cymene-H), 5.21 (d, J = 6.3 Hz,
1 H, p-cymene-H), 5.07–5.00 (m, 1 H, N-CH-iPr2), 4.99 (d, J = 5.9 Hz,
1 H, p-cymene-H), 2.57 (s, 3 H, o-aniline-CH3), 2.55–2.51 (m, 1 H, CHiPr2), 2.21 (s, 3 H, p-cymene-CH3), 1.78 (s, 3 H, o-aniline-CH3), 1.73 (d,
J = 6.7 Hz, 3 H, N-CH3-iPr), 1.46 (d, J = 6.6 Hz, 3 H, N-CH3-iPr), 1.16 (d,
J = 6.9 Hz, 3 H, p-cymene-CH3-iPr), 1.14 ppm (d, J = 6.9 Hz, 3 H, pcymene-CH3-iPr); 13C NMR (101 MHz, DMSO): d = 192.68 (NHC
carbon-Ru), 168.39, 153.04, 138.11, 137.97, 134.41, 134.23, 133.76,
133.66, 132.70, 131.14, 126.87, 126.07, 115.18, 113.74, 97.93, 91.75,
90.96, 89.80, 60.14, 58.91, 36.40, 28.71, 28.07, 27.65, 27.53, 25.40,
23.92, 23.46 ppm; ESI-MS (m/z): calcd for C31H37ClN3Ru: 588.172;
found: 588.007, [(h6-p-cymene)Ru(L10)Cl] + ; elemental analysis calcd
(%) for C31H37N3ClRuPF6 : C 50.79, H 5.09, N 5.73; found: C 50.99, H
5.01, N 5.69.
Acknowledgments
We thank the National Natural Science Foundation of China
(Grant No. 21671118) and the Taishan Scholars Program, Shandong Provincial Natural Science Foundation (ZR2018MB023),
The Key Laboratory of Polymeric Composite & Functional Materials of Ministry of Education (PCFM-2017-01), Excellent Experiment project of Qufu Normal University (jp201705) for support.
Conflict of interest
The authors declare no conflict of interest.
Keywords: anticancer · imine-N-heterocyclic carbene
ruthenium(II) complexes · structure–activity relationship
[(h6-p-Cymene)Ru(L9)Cl]PF6 (9): Yield: 51.1 mg (69 %). 1H NMR
(500 MHz, CDCl3): d = 7.59 (d, J = 2.1 Hz, 1 H, imidazole-H), 7.43 (t,
J = 7.7 Hz, 1 H, imidazole-H), 7.38–7.32 (m, 2 H, Ar-H), 7.31 (d, J =
2.1 Hz, 1 H, Ar-H), 5.83 (d, J = 6.2 Hz, 1 H, p-cymene-H), 5.20 (d, J =
6.0 Hz, 1 H, p-cymene-H), 5.05 (d, J = 6.1 Hz, 1 H, p-cymene-H), 4.99
(d, J = 6.2 Hz, 1 H, p-cymene-H), 4.54–4.39 (m, 2 H, nBu-CH2), 3.56–
3.45 (m, 1 H, o-aniline-CH-iPr2), 2.60–2.45 (m, 2 H, o-aniline-CH-iPr2
and p-cymene-CH-iPr2), 2.42 (s, 3 H, p-cymene-CH3), 2.25 (s, 3 H,
imine-CH3), 2.03–1.99 (m, 2 H, nBu-CH2), 1.50–1.46 (m, 2 H, nBu-CH2),
1.45 (d, J = 6.7 Hz, 3 H, o-aniline-CH3-iPr2), 1.25 (d, J = 6.6 Hz, 3 H, oaniline-CH3-iPr2), 1.17 (d, J = 7.0 Hz, 3 H, p-cymene-CH3-iPr), 1.15 (d,
J = 6.6 Hz, 3 H, o-aniline-CH3-iPr2), 1.11 (d, J = 6.8 Hz, 3 H, p-cymene-
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[1] R. L. Siegel, K. D. Miller, A. Jemal, CA-Cancer J. Clin. 2018, 68, 7 – 30.
[2] a) L. H. Guo, W. J. Liu, C. L. Chen, Mater. Chem. Front. 2017, 1, 2487 –
2494; b) W. A. Herrmann, Angew. Chem. Int. Ed. 2002, 41, 1290 – 1309;
Angew. Chem. 2002, 114, 1342 – 1363; c) L. H. Guo, S. Y. Dai, X. L. Sui,
C. L. Chen, ACS Catal. 2016, 6, 428 – 441; d) L. H. Guo, C. L. Chen, Sci.
China Chem. 2015, 58, 1663 – 1673.
[3] a) T. C. Johnstone, K. Suntharalingam, S. J. Lippard, Chem. Rev. 2016,
116, 3436 – 3486; b) Z. Liu, P. J. Sadler, Acc. Chem. Res. 2014, 47, 1174 –
1185; c) G. Shi, S. Monro, R. Hennigar, J. Colpitts, J. Fong, K. Kasimova,
H. Yin, R. DeCoste, C. Spencer, L. Chamberlain, A. Mandel, L. Lilgec, S. A.
McFarland, Coord. Chem. Rev. 2015, 282 – 283, 127 – 138; d) F. Li, J. G. Collins, F. R. Keene, Chem. Soc. Rev. 2015, 44, 2529 – 2542; e) K. B. Garbutcheon-Singh, M. P. Grant, B. W. Harper, A. M. Krause-Heuer, M. Manohar, N.
10
2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!
Full Paper
[11] Y. Li, B. Liu, X. R. Lu, M. F. Li, L. N. Ji, Z. W. Mao, Dalton Trans. 2017, 46,
11363 – 11371.
[12] Z. Liu, A. Habtemariam, A. M. Pizarro, S. A. Fletcher, A. Kisova, O. Vrana,
L. Salassa, P. C. A. Bruijnincx, G. J. Clarkson, V. Brabec, P. J. Sadler, J. Med.
Chem. 2011, 54, 3011 – 3026.
[13] S. Karmakar, S. Chatterjee, K. Purkait, A. Mukherjee, Dalton Trans. 2016,
45, 11710 – 11722.
[14] a) Z. Liu, R. J. Deeth, J. S. Butler, A. Habtemariam, M. E. Newton, P. J.
Sadler, Angew. Chem. Int. Ed. 2013, 52, 4194 – 4197; Angew. Chem. 2013,
125, 4288 – 4291; b) H. R. Zhang, L. H. Guo, Z. Z. Tian, M. Tian, S. M.
Zhang, Z. S. Xu, P. W. Gong, X. F. Zheng, J. Zhao, Z. Liu, Chem. Commun.
2018, 54, 4421 – 4424.
[15] H. Y. Huang, P. Y. Zhang, B. L. Yu, Y. Chen, J. Q. Wang, L. N. Ji, H. Chao, J.
Med. Chem. 2014, 57, 8971 – 8983.
[16] a) V. Novohradsky, J. Yellol, O. Stuchlikova, M. D. Santana, H. Kostrhunova, G. Yellol, J. Kasparkova, D. Bautista, J. Ruiz, V. Brabec, Chem. Eur. J.
2017, 23, 15294 – 15299; b) M. H. Chen, F. X. Wang, J. J. Cao, C. P. Tan,
L. N. Ji, Z. W. Mao, ACS Appl. Mater. Interfaces 2017, 9, 13304 – 13314.
[17] H. Wang, J. A. Joseph, Free Radical Biol. Med. 1999, 27, 612 – 616.
[18] a) P. Saftig, J. Klumperman, Nat. Rev. Mol. Cell Biol. 2009, 10, 623 – 635;
b) M. E. Guicciardi, M. Leist, G. J. Gores, Oncogene 2004, 23, 2881 – 2890;
c) G. Kroemer, M. Jttel, Nat. Rev. Cancer 2005, 5, 886 – 897; d) H. C.
Chen, J. W. Tian, W. J. He, Z. J. Guo, J. Am. Chem. Soc. 2015, 137, 1539 –
1547.
[19] P. Boya, G. Kroemer, Oncogene 2008, 27, 6434 – 6451.
[20] S. B. Jensen, S. J. Rodger, M. D. Spicer, J. Organomet. Chem. 1998, 556,
151 – 158.
[21] a) J. A. Deng, H. Y. Gao, F. M. Zhu, Q. Wu, Organometallics 2013, 32,
4507 – 4515; b) M. L. Rosenberg, E. Langseth, A. Krivokapic, N. S. Gupta,
M. Tilset, New J. Chem. 2011, 35, 2306 – 2313; c) M. Frøseth, K. A. Netland, C. Rømming, M. Tilset, J. Organomet. Chem. 2005, 690, 6125 –
6132; d) M. L. Rosenberg, A. Krivokapic, M. Tilset, Org. Lett. 2009, 11,
547 – 550; e) S. Dastgir, K. S. Coleman, A. R. Cowley, M. L. H. Green, Organometallics 2006, 25, 300 – 306; f) A. Krajete, G. Steiner, H. Kopacka, K. H.
Ongania, K. Wurst, M. O. Kristen, P. Preishuber-Pflgl, B. Bildstein, Eur. J.
Inorg. Chem. 2004, 1740 – 1752.
Orkey, J. R. Aldrich-Wright, Curr. Top. Med. Chem. 2011, 11, 521 – 542;
f) N. Muhammad, Z. J. Guo, Curr. Opin. Chem. Biol. 2014, 19, 144 – 153.
[4] a) V. Cepeda, M. A. Fuertes, J. Castilla, C. Alonso, C. Quevedo, J. M.
Prez, Anti-Cancer Agents Med. Chem. 2007, 7, 3 – 18; b) E. R. Jamieson,
S. J. Lippard, Chem. Rev. 1999, 99, 2467 – 2498; c) G. Chu, J. Biol. Chem.
1994, 269, 787 – 790.
[5] a) L. Kelland, Nat. Rev. Cancer 2007, 7, 573 – 584; b) L. Galluzzi, L. Senovilla, I. Vitale, J. Michels, I. Martins, O. Kepp, M. Castedo, G. Kroemer, Oncogene 2012, 31, 1869 – 1883; c) Y. Y. You, H. Hu, L. Z. He, T. F. Chen,
Chem. Asian J. 2015, 10, 2744 – 2754.
[6] a) A. Leonidova, G. Gasser, ACS Chem. Biol. 2014, 9, 2180 – 2193; b) Y. L.
Yang, L. H. Guo, Z. Z. Tian, Y. T. Gong, H. M. Zheng, S. M. Zhang, Z. S.
Xu, X. X. Ge, Z. Liu, Inorg. Chem. 2018, DOI: 10.1021/acs.inorgchem.8b01656. c) Q. Du, L. H. Guo, M. Tian, X. X. Ge, Y. L. Yang, X. Y.
Jian, Z. S. Xu, Z. Z. Tian, Z. Liu, Organometallics 2018, DOI: 10.1021/acs.organomet.8b00402.
[7] a) C. G. Hartinger, N. Metzler-Nolte, P. J. Dyson, Organometallics 2012,
31, 5677 – 5685; b) M. R. Gill, J. A. Thomas, Chem. Soc. Rev. 2012, 41,
3179 – 3192; c) M. Li, L. H. Lai, Z. N. Zhao, T. F. Chen, Chem. Asian J.
2016, 11, 310 – 320; d) N. P. Barry, P. J. Sadler, Chem. Commun. 2013, 49,
5106 – 5131; e) K. Suntharalingam, W. Lin, T. C. Johnstone, P. M. Bruno,
Y. R. Zheng, M. T. Hemann, S. J. Lippard, J. Am. Chem. Soc. 2014, 136,
14413 – 14416; f) C. Scolaro, A. Bergamo, L. Brescacin, R. Delfino, M. Cocchietto, G. Laurenczy, T. J. Geldbach, G. Sava, P. J. Dyson, J. Med. Chem.
2005, 48, 4161 – 4171; g) C. H. Leung, H. J. Zhong, D. S. H. Chan, D. L.
Ma, Coord. Chem. Rev. 2013, 257, 1764 – 1776; h) B. Y. W. Man, H. M.
Chan, C. H. Leung, D. S. H. Chan, L. P. Bai, Z. H. Jiang, H. W. Li, D. L. Ma,
Chem. Sci. 2011, 2, 917 – 921.
[8] a) L. Biancalana, L. K. Batchelor, T. Funaioli, S. Zacchini, M. Bortoluzzi, G.
Pampaloni, P. J. Dyson, F. Marchetti, Inorg. Chem. 2018, 57, 6669 – 6685;
b) M. Tian, J. J. Li, S. M. Zhang, L. H. Guo, X. D. He, D. L. Kong, H. R.
Zhang, Z. Liu, Chem. Commun. 2017, 53, 12810 – 12813; c) J. J. Li, L. H.
Guo, Z. Z. Tian, M. Tian, S. M. Zhang, K. Xu, Y. C. Qian, Z. Liu, Dalton
Trans. 2017, 46, 15520 – 15534; d) S. Movassaghi, S. Singh, A. Mansur,
K. K. H. Tong, M. Hanif, H. U. Holtkamp, T. Sçhnel, S. M. F. Jamieson, C. G.
Hartinger, Organometallics 2018, 37, 1575 – 1584.
[9] L. Oehninger, M. Stefanopoulou, H. Alborzinia, J. Schur, S. Ludewig, K.
Namikawa, A. MuÇoz-Castro, R. W. Kçster, K. Baumann, S. Wçlfl, Dalton
Trans. 2013, 42, 1657 – 1666.
[10] L. Biancalana, S. Zacchini, N. Ferri, M. G. Lupo, G. Pampaloni, F. Marchetti, Dalton Trans. 2017, 46, 16589 – 16604.
Chem. Asian J. 2018, 00, 0 – 0
www.chemasianj.org
These are not the final page numbers! ÞÞ
Manuscript received: July 7, 2018
Revised manuscript received: August 3, 2018
Accepted manuscript online: August 12, 2018
Version of record online: && &&, 0000
11
2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Full Paper
FULL PAPER
Anticancer Complexes
Ruthenium anticancer complexes: A
series of novel ruthenium(II) p-cymene
complexes bearing versatile imine-Nheterocyclic carbene ligands were synthesized and characterized. The cytotoxicity of these complexes showed significant structure–activity relationships. In
addition, the mechanism of actions
(MoAs) of these complexes was explored by flow cytometry and confocal
microscopy imaging.
Yuliang Yang, Lihua Guo,*
Zhenzhen Tian, Xicheng Liu,
Yuteng Gong, Hongmei Zheng,
Xingxing Ge, Zhe Liu*
&& – &&
Imine-N-Heterocyclic Carbenes as
Versatile Ligands in Ruthenium(II) pCymene Anticancer Complexes: A
Structure–Activity Relationship Study
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Chem. Asian J. 2018, 00, 0 – 0
www.chemasianj.org
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2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!