Organometallic ruthenium and iridium phosphorus complexes: Synthesis, cellular imaging, organelle targeting and anticancer applications

Article abstract of DOI:10.1002/aoc.4685

The use of metal complexes containing phosphorus ligands as anticancer agents has not been well studied. In this work, eight novel half-sandwich Ir^III and Ru^II compounds with P^P-chelating ligands have been synthesized and fully characterized, and alongside two crystal structures were reported. All eight complexes displayed highly potent antiproliferative activity, up to nine times more potent than the clinical anticancer drug cisplatin towards A549 lung cancer cells. Complex Ir1, which has a simpler structure and highly potent antiproliferative activity, was selected to investigate in further mechanistic studies. No hydrolysis and nucleobase binding occurred for complex Ir1. In order to elucidate subcellular localization, the self-luminescence of the complex Ir1 was utilized. Ir1 can specifically target lysosomes and facilitate excessive production of reactive oxygen species, resulting in lysosomal membrane permeabilization in A549 cells. Release of cathepsin B and changes in the mitochondria membrane potential also contributed to the observed cytotoxicity of Ir1, which demonstrated an anticancer action mechanism that was different from that of cisplatin. The favorable results from biological and chemical research demonstrated that these types of complexes hold significant theranostic potential.

Full text of DOI:10.1002/aoc.4685

Received: 31 August 2018
DOI: 10.1002/aoc.4685
Revised: 8 October 2018
Accepted: 14 October 2018
F U L L P A P E R
Organometallic ruthenium and iridium phosphorus
complexes: Synthesis, cellular imaging, organelle targeting
and anticancer applications
JuanJuan Li1 | Zhenzhen Tian1 | Shumiao Zhang1 | Zhishan Xu1,2 | Xudong Mao1 |
Yumin Zhou1 | Zhe Liu1
1 Institute of Anticancer Agents
The use of metal complexes containing phosphorus ligands as anticancer
agents has not been well studied. In this work, eight novel half‐sandwich IrIII
and RuII compounds with P^P‐chelating ligands have been synthesized and
fully characterized, and alongside two crystal structures were reported. All
eight complexes displayed highly potent antiproliferative activity, up to nine
times more potent than the clinical anticancer drug cisplatin towards A549
lung cancer cells. Complex Ir1, which has a simpler structure and highly
potent antiproliferative activity, was selected to investigate in further mecha-
nistic studies. No hydrolysis and nucleobase binding occurred for complex
Ir1. In order to elucidate subcellular localization, the self‐luminescence of
the complex Ir1 was utilized. Ir1 can specifically target lysosomes and facilitate
excessive production of reactive oxygen species, resulting in lysosomal mem-
brane permeabilization in A549 cells. Release of cathepsin B and changes in
the mitochondria membrane potential also contributed to the observed cyto-
toxicity of Ir1, which demonstrated an anticancer action mechanism that
was different from that of cisplatin. The favorable results from biological and
chemical research demonstrated that these types of complexes hold significant
theranostic potential.
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
2 Department of Chemistry and Chemical
Engineering, Shandong Normal
University, Jinan 250014, China
Correspondence
Zhe 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.
Email: liuzheqd@163.com
Funding information
KEYWORDS
National Natural Science Foundation of
China, Grant/Award Number: Grant No.
21671118; Taishan Scholars Program
cellular imaging, cytotoxicity, lysosomes targeted, organometallic ruthenium and iridium phosphorus
complexes
1 | INTRODUCTION
(neurotoxicity, nephrotoxicity, myelosuppression, ototox-
icity and vomiting), which are due to reaction with off‐
FDA‐approved Pt‐based agents (cisplatin, carboplatin and
oxaliplatin) dominate conventional chemotherapy in a
series of solid tumors, and are widely used in chemother-
apy combinations.[1] However, only a small portion of the
Pt‐based drug can enter the body and form a biologically
active form of platinum–DNA adducts, therefore these
drugs have been limited by toxic side‐effects
target nucleophiles, along with the fact that advanced
patients rarely heal due to development of drug resistance
during treatment.[2,3] To overcome these problems, metal
complexes that differ from the anticancer mechanism of
cisplatin have been designed by many research
groups.[4–9] After platinum complexes, iridium (Ir) and
ruthenium (Ru) complexes have displayed great potential
Appl Organometal Chem. 2019;e4685.
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© 2019 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.4685

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1
as novel metal‐based anticancer drug candidates,[10–19]
for example, NAMI‐A and KP1019 are two Ru complexes
that are already in clinical trials.[20,21]
All the complexes were characterized through H‐NMR
spectra, elemental analyses (C, H and P) and mass spectros-
copy (MS).
A
series of half‐sandwich IrIII
Organelle targeting is essential for developing specific
and effective cancer therapeutics, especially for chemother-
apy.[22–24] Organelle targeting can increase drug concentra-
tion in its active form at the target where the drug works
by delivering a drug to the cellular organelle, which may
have the potential to increase efficiency and reduce side‐
effects.[25–28] Lysosomes targeting has emerged as an effec-
tive strategy in degrading compartments of the cell, includ-
ing degrading proteins, membranes and other cellular
organelles.[29] Complexes target lysosomes and then lyso-
somal membrane permeabilization (LMP) is increased,
which causes cathepsins released from lysosomes to cytosol
and initiate apoptosis. The increased LMP and subsequent
cell death may be effective in cancer treatment, on condition
that lysosomes of cancer cells can be the intended target.[30]
Metal complexes possessing O^O, O^N, and especially
N^N‐chelating ligands have been extensively studied;[31–
pentamethylcyclopentadienyl and RuII arene complexes
containing four diverse P^P‐chelating ligands of the type
[(Cpx/Arene)M(P^P)Cl]PF6, where M = Ir, Cpx is
pentamethylcyclopentadienyl (Cp*) or 1‐biphenyl‐2,3,4,5‐
tetramethyl cyclopentadienyl (CpxbiPh); M = Ru, arene is
2‐phenylethanol‐1‐ol (bz‐EA) and p‐cymene (p‐cym), and
P^P is four different 1,2‐bis (diphenylphosphino)‐based
chelating ligands were investigated. Eight half‐sandwich
iridium/ruthenium complexes Ir1–Ir5, Ru1–Ru3
(Figure 1) were synthesized by the reactions between the
ligands L1–L4 and the dinuclear iridium or ruthenium pre-
cursors dimer in methanol at ambient temperature. But the
synthesis of part of the metal complexes was unsuccessful.
All the complexes were newly synthesized and were iso-
lated as PF6 salts. The 1H‐NMR (500 MHz) spectra of com-
plexes Ir1–Ir5, Ru1–Ru3 are shown in Figures S6–S13.
38]
however, complexes containing P^P‐chelating ligands
are still in their infancy.[39] Our previous work showed that
half‐sandwich complexes bearing BINAP as P^P‐chelating
ligand possess very promising anticancer properties; how-
ever, utilizing the self‐luminescence of the complexes in
elucidating subcellular localization and further explana-
tions of the mechanism of anticancer properties were not
explored.[40] Therefore, it is necessary to develop novel
metal phosphorus complexes that not only possess organ-
elle targeting strategies but also have high anticancer activ-
ity. To meet this goal, we synthesized a series of new Ir (III)
and Ru (II) compounds including different P^P‐chelating
ligands (Figure 1). These complexes not only displayed
potent antiproliferative activity, but also target specific
lysosomes and cause damage to lysosomes. We also sys-
temically studied their MoA, including nucleobase bind-
ing, cellular uptake mechanisms, lyososomal damage,
cathepsin B release, apoptosis, reactive oxygen species
(ROS), cell cycle, mitochondrial membrane potential
(MMP) changes, and catalytic NADH analysis. We demon-
strated that this class of complexes is attractive as novel
bioimaging and anticancer agents.
2.1.2 | X‐ray crystal structural analysis
During the preparation of the complexes, single crystals
of [(η5‐Cp*)Ir(L3)Cl]PF6 (Ir3) and [(η6‐p‐cym)Ru(L4)Cl]
PF6 (Ru3) were grown from hexane/dichloromethane
solution, and their structures were elucidated by X‐ray
crystallography. They are arranged in the monoclinic
and triclinic crystal systems with the P2 (1), P‐1 space
groups, respectively. The asymmetric unit of Ir3 and
Ru3 consists of a cation and hexafluorophosphate anions.
Details of crystallographic data, selected bond lengths
and angles with estimated standard deviations are listed
in Tables 1 and 2. ORTEP diagrams are shown in
Figure 2. The crystal structure determination showed that
both complexes adopt the classical pseudo‐octahedral
three‐legged piano‐stool geometry. As for Ir3, the η5‐
cyclopentadienyl ring displays the common π‐bonded
η5‐coordination mode, and the P^P ligands, occupying
two coordination positions, occupy a bidentate chelate
coordination mode (P^P). Finally, a chloride ion occupies
the final site in the coordination sphere.
Compared with complexes contain the P^P‐chelating
ligand BINAP,[40] the distance between the centroid of
η5‐Cp* or η6‐p‐cym and the metal center (1.8824 Å,
1.7616 Å, respectively) in Ir3 and Ru3 are shorter, due
to the comparatively weak trans effect of the ligands in
Ir3 and Ru3. It has been reported that the steric hin-
drance around the metal center was reflected by the bite
angle in Cp*(P–P)MX.[39,41,42] Ru3 exhibits a smaller bite
angle than Ir3 when comparing the bite angles P1−M
−P2, P1−M–Cl, and P2−M–Cl. The two complexes of Ir3
and Ru3 have similar M−Cl and M−P bond distances.
2 | RESULTS AND DISCUSSION
2.1 | Syntheses and X‐ray crystal
structural analysis
2.1.1 | Syntheses
All the complexes were synthesized using an analogical
procedureaccording to thereported method (Scheme 1).[40]

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FIGURE 1 Organometallic IrIII
cyclopentadienyl [(η5‐Cpx)Ir(P^P)Cl]PF6
and RuII arene [(η6‐arene)Ru(P^P)Cl]PF6
complexes studied in this work
investigated by means of MTT assay. For the purposes
of comparison, the toxicities and the IC50 (concentration
where 50% of the cell growth is inhibited) values of cis-
platin (CDDP) were also determined on the same cell
lines, and the results are listed in Table 3. As shown in
Table 3, the antiproliferative activity of the complex Ir1
containing L1 is 3.4 × (towards A549 lung cancer cells)
and 2.5 × (towards HeLa human cervical cancer) higher
than the complex Ir2 containing L2, showing a signifi-
cant decrease in anticancer activity upon introduction of
the vinyl group in L2. This trend is also exhibited
between biphenyl complexes Ir4 and Ir5. Adding a meth-
ylene group to L3 based on ligand L1, the anticancer
SCHEME 1 Synthesis of respective half‐sandwich IrIII and RuII
complexes
2.2 | Cytotoxicity
The cytotoxicity of complexes Ir1–Ir5, Ru1–Ru3 at vari-
ous concentrations for 24 hr towards human cervical can-
cer HeLa and A549 human lung cancer cell lines was

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TABLE 1 Crystallographic data for [(η5‐Cp*)Ir(L3)Cl]PF6 (Ir3)
and [(η6‐p‐cym)Ru(L4) Cl]PF6 (Ru3)
is 2 × more active than Ru2 containing L2 against HeLa
human cervical cancer cells, suggesting that the introduc-
tion of a benzene ring on the ligand L2 can increase the
anticancer activity of the complexes to some extent.
When more benzene rings are added to the ligand L4 to
form ligand BINAP, the anticancer activity of the corre-
sponding η6‐p‐cym ruthenium complex is further
increased (IC50 from 5.6 to 1.4 μM).[40] Another striking
result is that the biphenyl complex Ir4 displayed lower
IC50 values than the structurally similar Cp* derivative
Ir1, and similar rules have been reported by Aird
et al.[44] The results clearly indicate that subtle structural
changes can have a significant impact on the antiprolifer-
ative activity. Ir1 not only has a simpler structure but also
has a relatively high anticancer activity against A549 lung
cancer cells, and prompted us to further investigate the
mechanism of action using Ir1.
Ir3
Ru3
Formula
MW
C37H41Cl3F6P3Ir
1005.52
C40H38ClF6P3Ru
862.13
Cryst. size (mm)
λ (Å)
0.47 × 0.40 × 0.20
0.71073
0.28 × 0.22 × 0.20
0.71073
293(2)
Temp. (K)
Cryst. syst
Space group
a (Å)
293(2)
Monoclinic
P2 (1)
Triclinic
P‐1
13.2401(12)
17.4358(15)
26.194(2)
90.00
11.097(2)
11.296(2)
16.514(3)
81.59(3)
73.81(3)
86.05(3)
1965.7(6)
2
b (Å)
c (Å)
α (°)
β (°)
92.7920(10)
90.00
The antiproliferative activities of the most potent
complex Ir1 were further evaluated against human bron-
chial epithelial normal cells 16HBE (IC50 = 6.5 0.7).
Weak selectivity was observed between cancer cells vs.
normal cells.
γ (°)
Vol. (Å3)
6039.8(9)
6
Z
R1 [I > 2sigma(I)]
wR2 [I > 2sigma(I)]
GOF
0.0699
0.0375
0.1513
0.1042
2.3 | Hydrolysis studies
1.062
1.058
Substitution of mono‐ligand chloride by H2O for metal
complexes is a significant element influencing applica-
tions in medicine, such as activation of the Pt‐Cl bond
by Pt‐OH2 in cisplatin. In this study, the synthesized
metal complexes have been dissolved using DMSO for
NMR analysis and biological tests. Therefore, the hydro-
lysis of complex Ir1 in DMSO/D2O (3:7) was determined
by 1H‐NMR at 37°C (Figure S1), and no change in the 1H‐
NMR of the complex was observed during incubation for
24 hr, and was also unchanged after the addition of 16 ×
NaCl. The results suggest that hydrolysis did not occur
under test conditions, and the intact metal complex is
responsible for the observed cytotoxicity.
TABLE 2 Selected bond lengths (Å) and angles (deg) for [(η5‐
Cp*)Ir(L3)Cl]PF6 (Ir3) and [(η6‐p‐cym)Ru(L4)Cl]PF6 (Ru3)
Ir3
Ru3
2.223(2)
2.223(2)
2.249(2)
2.262(2)
2.276(2)
2.310(2)
M−C (cyclopentadienyl/arene)
2.193(13)
2.211(14)
2.246(17)
2.267(17)
2.297(15)
M−C (centroid)
M−P1
1.8824
1.7616
2.330(4)
2.312(4)
2.405(4)
91.19(15)
86.32(15)
86.61(15)
2.3046(8)
2.3209(10)
2.4005(9)
83.48(3)
81.54(4)
84.45(3)
M−P2
M−Cl
2.4 | Reaction with NADH
P1−M−P2
P1−M−Cl
P2−M−Cl
It is known that NADH (reduced nicotinamide adenine
dinucleotide) and its oxidized form NAD+ play a central
role in mitochondrial function and cell death.[45] It has
been reported that metal complexes can catalytically con-
vert coenzyme NAD+/NADH to produce ROS H2O2,[46]
which can damage lysosomes and trigger the lysosomal
pathway of apoptosis.[47] Therefore, the impact of Ir1
(1 μM) on NADH (130 μM) was monitored in
MeOH/H2O (3:7) by UV–Vis at 298 K, and NADH was
incubated in the same solution as control (Figure 3).
The conversion from NADH to NAD+ was determined
activity of complex Ir3 is also reduced compared with
that of complex Ir1. However, the anticancer activity of
complex Ru1 containing the P^P‐chelating ligand L1 is
lower than that of Ir1 and Ir4 containing L1, probably
due to the hydrophilicity of −OH causing difficulties in
entering the cell membrane.[43] A similar result has also
appeared in our previous reports.[40] Ru3 containing L4

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FIGURE 2 X‐ray crystal structures with
atom numbering schemes for (a) [(η5‐Cp*)
Ir(L3)Cl]PF6 (Ir3); (b) [(η6‐p‐cym)Ru(L4)
Cl]PF6 (Ru3) with thermal ellipsoids
drawn at 50% probability. The hydrogen
atoms, dichloromethane and counter ions
−
PF6 have been omitted for clarity
based on NADH having a UV absorption at 339 nm but
not NAD+. The turnover number (TON) of complex Ir1
(TON = 18) was calculated, suggesting that the complex
has a strong catalytic ability to convert coenzyme NAD
+/NADH couple.
TABLE 3 Inhibition of growth of A549 and HeLa cancer cells by
complexes Ir1–Ir5, Ru1‐Ru3 and comparison with cisplatin
(CDDP) recorded over a period of 24 hra
IC50 (μM)
Complex
A549
HeLa
16HBE
[(η5‐Cp*)Ir(L1)Cl]PF6 (Ir1)
[(η5‐Cp*)Ir(L2)Cl]PF6 (Ir2)
[(η5‐Cp*)Ir(L3)Cl]PF6 (Ir3)
[(η5‐Cpxbiph)Ir(L1)Cl]PF6 (Ir4)
[(η5‐Cpxbiph)Ir(L2)Cl]PF6 (Ir5)
[(η6‐bz‐EA)Ru(L1)Cl]PF6
(Ru1)
[(η6‐p‐cym)Ru(L2)Cl]PF6
(Ru2)
3.0 0.2 5.2 0.6 6.5 0.7
10.3 0.6 12.9 0.4
3.9 0.4 8.5 0.5
2.5 | Interaction with nucleobases
The principal mode of action of cisplatin is formation of
covalent Pt–DNA adducts.[1] Therefore, the binding of
model nucleobase 9‐methyladenine (9‐MeA) to complex
Ir1 was studied. 9‐MeA (3 mM) was added to the solution
of complex Ir1 (1.0 mM) in DMSO/D2O (3:7), and H‐
NMR spectra were monitored at 310 K (Figure S2). No
2.3 0.1 4.3 0.9
7.4 0.7 10.2 0.6
32.9 0.2 38.6 1.1
1
5.1 0.5 7.9 0.3
5.6 0.8 3.9 0.7
21.3 1.7 7.5 0.2
nucleobase adduct was formed detected by NMR and MS.
[(η6‐p‐cym)Ru(L4)Cl]PF6
(Ru3)
2.6 | Subcellular localization and
mechanisms of cellular uptake
CDDP
aCells were treated with different concentrations of the iridium, ruthenium
complexes and cisplatin for 24 hr. Cell viability was determined by the
MTT assay, and data were calculated as described in the Experimental sec-
tion. Data are presented as means SD obtained in at least three indepen-
dent experiments.
Toward elucidating the mechanism of action of Ir1, the
localization of Ir1 in A549 cells was monitored by confo-
cal fluorescence microscopy (Figure 4). We used the Lys‐
specific fluorescent dye LTDR or mitochondria‐specific
probe MTDR tracker to perform co‐incubation with Ir1
in live A549 cells. As shown in Figure 4, an excellent
FIGURE 3 (a) UV–Vis spectra of the reaction of NADH (100 μM) in 30% MeOH/70% H2O (V:V) at 298 K for 8 hr. (b) UV–Vis spectra of the
reaction of NADH (130 μM) with Ir1 (1 μM) in 30% MeOH/70% H2O (V:V) at 298 K for 8 hr

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FIGURE 4 (a) Confocal microscopy images of A549 cells co‐labeled with Ir1 (10 μM, 0.5 hr) and LTDR (100 nM, 0.5 hr). (b) Confocal
microscopy images of A549 cells co‐labeled with Ir1 (10 μM, 0.5 hr) and MTDR (75 nM, 0.5 hr). The excitation and emission bands for
complex: λex = 488 nm, λem = 520 30 nm; for MTDR: λex = 644 nm, λem = 700 30 nm; for LTDR: λex = 594 nm, λem = 630 30 nm. Scale
bar: 20 μm
superimposition between the Lys‐specific fluorescent dye
LTDR and Ir1 could be observed after incubating. The
Pearson's R‐value of colocalization is 0.92, demonstrating
that most of the complex specifically targeted lysosomes.
Meanwhile, minimal colocalization of Ir1 with MTDR
was observed. The Pearson's R‐value of colocalization is
0.3. The results indicate that Ir1 possesses lysosome
targeting specificity. Lysosome plays crucial roles in a
wide range of cell processes, including cell death.
Furthermore, to obtain more insight into the mecha-
nism of the cellular entry of Ir1, we pretreated A549 cells
with chloroquine, an endocytosis modulator that can
inhibit the acidification of endosomes, the energy inhibi-
tor CCCP (carbonyl cyanide m‐chlorophenyl hydrazone)
or incubation with Ir1 at lower temperature (4°C),
respectively (Figure S3), and cellular uptake efficiency
was reduced as shown by confocal microscopy, indicating
that cellular uptake of Ir1 was mainly through an energy‐
dependent mechanism.
effective probe in studying the integrity of the acidic
organelles) staining, which emits red fluorescence in lyso-
somes. As shown in Figure 5, A549 cells exposed to Ir1
(3 × IC50) for 1 hr showed distinct red fluorescence in
lysosomes. However, when the cells were incubated for
15 hr and 24 hr, the red fluorescence of AO arresting
reduced in a time‐dependent way, which manifested that
lysosomes were seriously mangled.
The involvement of lysosomes and lysosomal prote-
ases is seen as an extra point of turn into apoptosis in
multifarious cell types. Disruption of the integrity of lyso-
somes can cause LMP (a crucial regulator of cell apopto-
sis), and promote cathepsin B released from lysosomes to
cytosol. Cathepsin B Kit Magic Red was employed to
detect the release of cathepsin B by confocal microscopy,
and Hoechst 33342 was used to label the nuclei. Confocal
microscopy displayed a dose‐dependent augmentation in
magic red fluorescence in A549 cells treated with Ir1.
Compared with the control, an amount of cathepsin B
was released in the present of Ir1 at 3 × IC50.
2.7 | Lysosomal damage and induction of
intracellular ROS
2.7.2 | Induction of intracellular ROS
Excessively produced ROS have been found to be an
important component through a Fenton‐like reaction to
result in a more forthright influence on the lysosomal
membrane, causing peroxidative damage to the membrane
lipids, and leading to uncontrolled lysosomal permeability,
along with modulation of apoptosis.[50] We further used
fluorescent probe DCFH‐DA, emitting green fluorescence
upon oxidation by ROS, to measure the intracellular ROS
2.7.1 | Lysosomal damage
The integrity of the lysosomes can be disrupted by metal
complexes, which are well known to have a strong influ-
ence on promoting excessive generation of ROS and
bringing about increased lysosomal permeability.[48,49]
We incubated A549 cells with complex to evaluate the
lysosomal integrity by acridine orange (AO, a very

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FIGURE 5 (a) Observation of lysosomal disruption in A549 cells caused by Ir1 and stained by AO (5 μM, 15 min). λex = 488 nm,
λem = 510 20 nm; λem = 625 20 nm. The cells were treated with vehicle (1% DMSO), Ir1 (9 μM) for 8 hr, Ir1 (9 μM) for 15 hr, and Ir1
(9 μM) for 24 hr, respectively. Scale bar: 10 μm. (b) Changes in cathepsin B location induced by different concentrations of Ir1 for 12 hr in
A549 cells using the fluorogenic substrate Magic Red MR‐(RR)2. Magic Red MR‐(RR)2 λex = 543 nm, λem = 630 20 nm. From left to right
are vehicle (1% DMSO), Ir1 3 μM, Ir1 6 μM, Ir1 9 μM, respectively. Scale bar: 20 μm
level by flow cytometry analysis. As indicated in Figure 6
and Table S1 the ROS levels of A549 cells were very high
even in the presence of a low concentration of Ir1
(0.25 × IC50); Ir1 exhibits excellent activity to generate
ROS. These results demonstrated that Ir1 could be used
to induce oxidative damage and promote apoptosis.
in advance of the loss of MMP.[47] Therefore, we per-
formed a flow cytometric analysis to determine whether
apoptosis and MMP reduction occurred. Firstly, apoptosis
induced by Ir1 was elucidated and analyzed by flow cyto-
metric analysis. A549 cells were exposed to Ir1 at 0.5, 1
and 2 equipotent concentrations of IC50 for 24 hr. As
shown in Figure 7 and Table S2, a small portion of cells
(12.1%) are in the apoptotic phase for control cells, and
treating with complex decreases the percentage of cells
in the viable phase dramatically, and a high apoptotic
rate (65.8%) can be achieved for Ir1 at 2 × IC50. z‐VAD‐
fmk (5 μM, pan‐caspase inhibitor) was used to further
2.8 | Apoptosis assay and MMP changes
Reactive oxygen species‐intervened release of cathepsins,
such as cathepsin B, takes place early during apoptosis,
FIGURE 6 ROS induction in A549 cancer cells caused by complex Ir1 at a concentration of 0.25 × IC50. (a) FL2 histogram for negative
control (untreated cells), positive control and Ir1. (b) Populations of cells in low and high levels of ROS after treatment of Ir1. Data are
quoted as mean SD of three replicates

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FIGURE 7 Flow cytometry detected the apoptosis based on annexin V and PI staining of A549 cells treated with different concentrations
of complex Ir1 after 24 hr at 310 K. The experiment was repeated three times, and representative photographs are displayed, with mean
values of three independent experiments. Data are presented as mean S.D. (a) Populations for cells treated by Ir1. (b) Histogram for A549
cells treated with different concentrations of Ir1 for 24 hr. (c) Populations for cells treated with different concentrations of Ir1 and the pan‐
caspase inhibitor z‐VAD‐fmk (5 μM) at 310 K
evaluate the contribution of various caspases to apoptosis.
The results showed that pretreatment of cells with z‐
VAD‐fmk prevented cell apoptosis induced by Ir1 signif-
icantly (Figure 7c; Table S3), revealing that apoptosis
arose in a caspase‐dependent manner.
adducts.[1,53] Therefore, we studied whether arresting
the cell cycle was involved in cell death induced by com-
plex Ir1 using flow cytometric analysis. The A549 cells
were exposed to Ir1 at 0.25, 0.5 and 1 × IC50 for 24 hr.
Flow cytometric studies revealed that the percentages of
cells in each cycle phase showed no significant change
(Figure S5; Table S5), indicating that complex Ir1 has
no effect on the cell cycle, which digresses the pathway
of the classical G2/M arrest phase induced by cisplatin.[3]
Therefore, we presumed that the correlation anticancer
mechanism of action between complex Ir1 and
platinum‐based drugs might be different.
Furthermore, JC‐1 was exploited to study intracellular
MMP dysfunction in A549 cells induced by Ir1 (at con-
centrations of 0.25, 0.5, 1 and 2 × IC50) using flow cytom-
etry. Very recently, metal complexes have been used to
attempt to induce cell apoptosis by interfering with the
MMP, finally leading to cell death.[51,52] As shown in Fig-
ure S4 and Table S4, the increasing portion of green fluo-
rescence confirmed that an increasing number of cells
lost their MMP, when cells were treated with complex
Ir1. MMP increased due to Ir1, probably due to the
ROS generated leading to opening of the mitochondrial
permeability transition pores and the release of cyto-
chrome c (the biomarker of apoptosis).
3 | CONCLUSION
In conclusion, we presented the successful development
of eight half‐sandwich IrIII and RuII complexes that reveal
ligand changes lead to a significant impact on the cyto-
toxicity, and the P^P‐chelating ligands are highly potent
in enhancing antiproliferative activity. The metal com-
plexes can specifically target to lysosomes and caused
lysosomal damages in A549 cancer cells. The unearthing
of the significant role of lysosome targeting specificity in
cancer cells of half‐sandwich metal complexes broadens
our strategy for the design of more active anticancer
2.9 | Cell cycle analysis
Platinum‐based drugs, such as cisplatin, have been used
to treat several forms of cancer mainly through forming
types of platinum–DNA adducts, for example, the cyto-
toxicity of cisplatin was mediated via cisplatin–DNA

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drugs. The significantly elevated excessive production of
ROS and release of cathepsin B ultimately result in
remarkable cytotoxicity, particularly in A549 human lung
cancer cells lines, rather than the metal–DNA adduct
mode of action similar to cisplatin. Flow cytometry stud-
ies have confirmed that the metal complexes induce apo-
ptosis, especially late apoptosis, and changes in the MMP
of cancer cells. The most detailed chemistry and biologi-
cal studies points to the fact that metal complexes like
Ir1 can be very effective as anticancer drug candidates.
equipped with room temperature stirrer and nitrogen
atmosphere. NH4PF6 (0.2 mmol) was added after con-
stant stirring for 12 hr. The reaction mixture was stirred
for 6 hr at room temperature, and precipitate was formed
in solution after complete conversion, methanol was
removed under reduced pressure and product was dis-
solved in dichloromethane and filtered through Celite fil-
tration funnel. Complexes were recrystallized by slow
diffusion of n‐hexane in a concentrated solution with
complex in dichloromethane and the corresponding com-
plexes (Ir1–Ir5, Ru1–Ru3) obtained.
4 | EXPERIMENTAL
4.1 | General information
4.2.1 | Synthesis of complexes Ir1–Ir5,
Ru1–Ru3
Unless otherwise noted, all manipulations were per-
formed using standard Schlenk tube techniques under
nitrogen atmosphere. The reagents IrCl3·nH2O (≥ 99%
purity), hydrated RuCl3·nH2O (≥ 99% purity), octan‐1‐ol
(≥ 99%) and nitric acid (72%), 2,3,4,5‐tetramethyl‐2‐
[(η5‐Cp*)Ir(L1)Cl]PF6
(Ir1)
reactant:
1,2‐bis
(diphenylphosphino) ethane (0.10 mmol) and metal
dimer [(η5‐Cp*)IrCl2]2. Yield: 34.1 mg, 37.6%. 1H‐NMR
3
(500 MHz, DMSO‐d6): δ 7.70 (t, JHH = 7.6 Hz, 2H,
CH2), 7.63–7.46 (m, 11H, CH), 7.17 (s, 4H CH), 7.01 (s,
3H, CH), 1.49 (s, 2H, CH2), 1.01 (s, 15H, Cp). Anal. calcd
for [(η5‐Cp*)Ir(L1)Cl]PF6 (906.15): C, 47.71; H, 4.34; P,
10.25; found: C, 47.63; H, 4.31; P, 10.26. MS: m/z
726.22. [(η5‐Cp*)Ir(L1) + H]+.
cyclopentenone
(95%),
1,2,3,4,5‐pentamethyl‐
cyclopentadiene (95%), butyllithium solution (1.6 M in
hexane), 1,2‐bis (diphenylphosphino) propare (98%),
trans‐1,2‐bis (diphenylphosphino) ethylene (96%), 1,2‐bis
(diphenylphosphino)
benzene
(98%),
1,2‐bis
[(η5‐Cp*)Ir(L2)Cl]PF6 (Ir2) reactant: trans‐1,2‐bis
(diphenylphosphino) ethylene and metal dimer [(η5‐Cp*)
IrCl2]2. Yield: 29.4 mg, 32.5%. 1H‐NMR (500 MHz,
(diphenylphosphino) ethane (98%), 2‐phenylethanol‐1‐ol
(bz‐EA) (98%), α‐terpinene (p‐cym) and cisplatin were
purchased from Sigma‐Aldrich. CpxbiphH[54] and [(η6‐bz‐
3
DMSO‐d6): δ 7.72 (t, JHH = 7.5 Hz, 2H, CH), 7.56 (t,
[40]
EA)RuCl2]2
were prepared as described. For the bio-
3JHH = 7.2 Hz, 2H, CH), 7.45 (t, JHH = 7.7 Hz, 4H, CH),
3
logical experiments, CCCP, z‐VAD‐fmk and cleaved
caspase‐3 were purchased from Apoptosis and
Epigenetice Company, NH4PF6 (Alfa Aesar), MTDR (Life
Technologies), LTDR (Life Technologies), MTT [3‐(4,5‐
dimethylthiazol‐2‐yl)‐2,5–diphenyltetrazolium bromide]
(Sigma‐Aldrich), Annexin V‐FITC Apoptosis Detection
Kit (Sigma‐Aldrich), JC‐1 (Sigma‐Aldrich), PBS (Sangon
Biotech), PI (Sigma‐Aldrich) were all used as received.
3
3
7.36 (t, JHH = 7.6 Hz, 4H, CH), 7.21 (dd, JHH = 33.2
3
Hz, JHH = 14.1 Hz, 6H, CH), 6.86 (s, 4H, CH), 1.14 (s,
15H, Cp). Anal. calcd for [(η5‐Cp*)Ir(L2)Cl]PF6 (904.13):
C, 47.82; H, 4.12; P, 10.28; found: C, 47.80; H, 4.11; P,
10.18. MS: m/z 724.20. [(η5‐Cp*)Ir(L2) + H]+.
[(η5‐Cp*)Ir(L3)Cl]PF6
(Ir3)
reactant:
1,2‐bis
(diphenylphosphino) propare and metal dimer [(η5‐Cp*)
IrCl2]2. Yield: 27.5 mg, 29.9%. 1H‐NMR (500 MHz,
DMEM
medium,
fetal
bovine
serum,
3
DMSO‐d6): δ 7.60–7.46 (m, 8H, CH), 7.40 (q, JHH = 7.1
penicillin/streptomycin mixture, trypsin/EDTA and PBS
were purchased from Sangon Biotech. Testing com-
pounds were dissolved in DMSO and diluted with the tis-
sue culture medium before use.
3
3
Hz, 8H, CH), 7.23 (dd, JHH = 10.9 Hz, JHH = 7.3 Hz,
2
4H, CH), 3.05 (d, JHH = 12.9 Hz, 2H, CH2), 2.90 (dd,
3
2
2JHH = 11.1 Hz, JHH = 3.5 Hz, 2H, CH2), 1.60 (dd, JHH
3
= 16.2 Hz, JHH = 7.7 Hz, 2H, CH2), 1.32 (s, 15H, Cp).
Anal. calcd for [(η5‐Cp*)Ir(L3)Cl]PF6 (920.16): C, 48.29;
H, 4.49; P, 10.10; found: C, 48.23; H, 4.39; P, 10.12. MS:
m/z 740.23. [(η5‐Cp*)Ir(L3) + H]+.
4.2 | Synthesis of complexes Ir1–Ir5 and
Ru1–Ru3
[(η5‐Cpxbiph)Ir(L1)Cl]PF6 (Ir4) reactant: 1,2‐bis
(diphenylphosphino) ethane (0.10 mmol) and metal dimer
General method. The ligand 1,2‐bis (diphenylphosphino)
propare, trans‐1,2‐bis (diphenylphosphino) ethylene, 1,2‐
[(η5‐Cpxbiph)IrCl2]2. Yield: 29.9 mg, 28.6%. H‐NMR (500
1
3
bis
(diphenylphosphino)
benzene
or
1,2‐bis
MHz, DMSO‐d6): δ 7.66 (dd, JHH = 15.8, 8.4 Hz, 4H,
3
(diphenylphosphino) ethane (0.10 mmol) and metal
dimer [(η5‐Cpx)IrCl2]2 or [(η6‐arene)RuCl2]2 (0.05 mmol)
were dissolved in methanol in a dry round‐bottom flask
CH), 7.63–7.47 (m, 12H, CH), 7.43 (ddd, JHH = 18.6 Hz,
3
3
3JHH = 12.0 Hz, JHH = 4.8 Hz, 5H, CH), 7.35 (d, JHH
=
3
3
8.4 Hz, 2H, CH), 7.16 (dd, JHH = 11.5 Hz, JHH = 7.4 Hz,

10 of 11
LI ET AL.
3
4H, CH), 7.09 (d, JHH = 8.4 Hz, 2H, CH), 3.11–3.05 (m,
2H, CH2), 2.72–2.65 (m, 2H, CH2), 1.72 (s, 6H, Cp), 1.49
(s, 6H, Cp). Anal. calcd for [(η5‐Cp*)Ir(L1)Cl]PF6
(1044.20): C, 54.05; H, 4.34; P, 8.90; found: C, 54.03; H,
4.31; P, 8.98. MS: m/z 864.27. [(η5‐Cpxbiph)Ir(L1) + H]+.
[(η5‐Cpxbiph)Ir(L2)Cl]PF6 (Ir5) reactant: trans‐1,2‐bis
(diphenylphosphino) ethylene and metal dimer [(η5‐
Cpxbiph)IrCl2]2. Yield: 28.9 mg, 27.7%. 1H‐NMR (500
ACKNOWLEDGEMENTS
The authors thank the National Natural Science Founda-
tion of China (Grant No. 21671118) and the Taishan
Scholars Program for support.
CONFLICT OF INTEREST
The authors declare no competing financial interest.
3
MHz, DMSO‐d6): δ 7.78–7.74 (m, 2H, CH), 7.71 (d, JHH
= 7.2 Hz, 2H, CH), 7.57 (d, JHH = 8.4 Hz, 2H, CH),
3
7.53–7.50 (m, 2H, CH), 7.46–7.30 (m, 9H, CH), 7.26–7.15
ORCID
(m, 6H, CH), 7.07 (s, 4H, CH), 6.85 (s, 4H, CH), 1.48 (s,
Zhe Liu https://orcid.org/0000-0001-5796-4335
6H, Cp), 1.29 (s, 6H, Cp). Anal. calcd for [(η5‐Cpxbiph
)
Ir(L2)Cl]PF6 (1042.18): C, 54.15; H, 4.16; P, 8.91; found:
C, 54.13; H, 4.11; P, 8.88. MS: m/z 862.25. [(η5‐Cpxbiph
)
REFERENCES
Ir(L2) + H]+.
[1] D. Wang, S. J. Lippard, Nat. Rev. Drug Discov. 2005, 4, 307.
[(η6‐bz‐EA)Ru(L1)Cl]PF6 (Ru1) reactant: 1,2‐bis
(diphenylphosphino) ethane (0.10 mmol) and metal
dimer [(η6‐bz‐EA)RuCl2]2). Yield: 24.5 mg, 30.5%. 1H‐
[2] Y. R. Zheng, K. Suntharalingam, T. C. Johnstone, H. Yoo, W.
Lin, J. G. Brooks, S. J. Lippard, J. Am. Chem. Soc. 2014, 136,
8790.
3
NMR (500 MHz, DMSO‐d6): δ 7.68 (t, JHH = 7.6 Hz, 2H,
[3] S. G. Awuah, Y. R. Zheng, P. M. Bruno, M. T. Hemann, S. J.
3
3
CH), 7.54 (dt, JHH = 14.6 Hz, JHH = 7.1 Hz, 6H, CH),
Lippard, J. Am. Chem. Soc. 2015, 137, 14,854.
3
7.46 (t, JHH = 7.6 Hz, 4H, CH), 7.28 (s, 3H, CH), 7.15
[4] Z. Liu, P. J. Sadler, Acc. Chem. Res. 2014, 47, 1174.
[5] Y. Jiang, X. Wang, D. Hu, Cell Death Dis. 2017, 8, 2815.
(s, 3H, CH), 6.04–5.98 (m, 2H, CH), 5.22 (s, 2H, CH),
3
4.72 (s, 1H, CH), 4.27 (t, JHH = 5.2 Hz, 1H, CH), 3.54
3
[6] E. Kahrović, A. Zahirović, S. Kraljević Pavelić, E. Turkušić, A.
Harej, J. Coord. Chem. 2017, 70, 1683.
(s, 2H, CH2), 2.90 (t, JHH = 10.9 Hz, 2H, CH2), 2.20 (t,
3JHH = 6.0 Hz, 2H, CH2), 2.02–1.94 (m, 2H, CH2). Anal.
calcd for [(η6‐bz‐EA)Ru(L1)Cl]PF6 (802.05): C, 50.91; H,
4.27; P, 11.59; found: C, 50.96; H, 4.31; P, 11.53. MS:
m/z 622.12. [(η6‐bz‐EA)Ru(L1) + H]+.
[7] J. X. Liang, H. J. Zhong, G. Yang, K. Vellaisamy, D. L. Ma, C.
H. Leung, J. Inorg. Biochem. 2017, 177, 276.
[8] C. Licona, M.‐E. Spaety, A. Capuozzo, M. Ali, R. Santamaria,
O. Armant, F. Delalande, A. V. Dorsselaer, S. Cianferani, J.
Spencer, M. Pfeffer, G. Mellitzer, C. Gaiddon, Oncotarget
2017, 8, 2568.
[(η6‐p‐cym)Ru(L2)Cl]PF6 (Ru2) reactant: trans‐1,2‐bis
(diphenylphosphino) ethylene and metal dimer [(η6 ‐p‐
1
cym)RuCl2]2. Yield: 27.0 mg, 33.2%. H‐NMR (500 MHz,
[9] F. X. Wang, M. H. Chen, Y. N. Lin, H. Zhang, C. P. Tan, L. N.
DMSO‐d6): δ 7.76–7.71 (m, 2H, CH), 7.57–7.53 (m, 2H,
3
Ji, Z. W. Mao, ACS Appl, Mater. Inter. 2017, 9, 42,471.
CH), 7.45 (dd, JHH = 10.3, 4.8 Hz, 8H, CH), 7.29 (s, 4H,
[10] V. Novohradsky, L. Zerzankova, J. Stepankova, A. Kisova, H.
Kostrhunova, Z. Liu, P. J. Sadler, J. Kasparkova, V. Brabec,
Metallomics 2014, 6, 1491.
CH), 7.11 (s, 4H, CH), 6.92–6.83 (m, 4H, CH), 6.21 (d,
3
3JHH = 6.0 Hz, 2H, CH), 5.19 (d, JHH = 6.1 Hz, 2H,
3
CH), 1.21 (s, 3H, CH3), 0.85 (d, JHH = 6.9 Hz, 6H,
CH3). Anal. calcd for [(η6‐p‐cym)Ru(L2)Cl]PF6 (812.07):
C, 53.24; H, 4.47; P, 11.44; found: C, 53.23; H, 4.45; P,
11.48. MS: m/z 632.14. [(η6‐p‐cym)Ru(L2) + H]+.
[11] R. Guan, Y. Chen, L. Zeng, T. W. Rees, C. Jin, J. Huang, Z. S.
Chen, L. Ji, H. Chao, Chem. Sci. 2018, 9, 5183.
[12] M. Ganeshpandian, M. Palaniandavar, A. Muruganantham, S.
K. Ghosh, A. Riyasdeen, M. A. Akbarsha, Appl. Organomet.
Chem. 2018, 32, 4154.
[(η6‐p‐cym)Ru(L4)Cl]PF6 (Ru3) reactant: 1,2‐bis
(diphenylphosphino) benzene and metal dimer [(η6 ‐p‐
1
[13] D. L. Ma, C. Wu, W. Tang, A. R. Gupta, F. W. Lee, G. Li, C. H.
cym)RuCl2]2. Yield: 31.7 mg, 36.8%. H‐NMR (500 MHz,
3
3
Leung, J. Mater. Chem. B 2018, 6, 537.
DMSO‐d6): δ 7.92 (dd, JHH = 10.7 Hz, JHH = 7.5 Hz,
6H, CH), 7.70–7.66 (m, 2H, CH), 7.65–7.62 (m, 2H, CH),
[14] S. Thota, D. A. Rodrigues, D. C. Crans, E. J. Barreiro, J. Med.
Chem. 2018, 61, 5805.
3
3
7.58 (t, JHH = 7.3 Hz, 4H, CH), 7.53 (t, JHH = 7.4 Hz,
3
3
2H, CH), 7.38 (t, JHH = 7.4 Hz, 4H, CH), 7.06 (t, JHH
= 9.1 Hz, 4H, CH), 6.34 (d, JHH = 6.1 Hz, 2H, CH), 6.29
(d, JHH = 6.3 Hz, 2H, CH), 2.40–2.36 (m, 1H, CH), 1.26
[15] G. Devagi, F. Dallemer, P. Kalaivani, R. Prabhakaran,
3
J. Organomet. Chem. 2018, 854, 1.
3
[16] K. M. Knopf, B. L. Murphy, S. N. MacMillan, J. M. Baskin, M.
P. Barr, E. Boros, J. J. Wilson, J. Am. Chem. Soc. 2017, 139,
14,302.
3
(s, 3H, CH2), 0.71 (d, JHH = 6.9 Hz, 6H, CH3). Anal.
calcd for [(η6‐p‐cym)Ru(L4)Cl]PF6 (862.08): C, 55.72; H,
4.44; P, 10.78; found: C, 55.73; H, 4.41; P, 10.88. MS:
m/z 682.15. [(η6‐p‐cym)Ru(L4) + H]+.
[17] L. Zeng, P. Gupta, Y. Chen, E. Wang, L. Ji, H. Chao, Z.‐S. Chen,
Chem. Soc. Rev. 2017, 46, 5771.

LI ET AL.
11 of 11
[18] Y. Han, Z. Tian, S. Zhang, X. Liu, J. Li, Y. Li, Y. Liu, M. Gao, Z.
[39] F. Zhang, J. Jia, S. Dong, W. Wang, C.‐H. Tung, Organometal-
lics 2016, 35, 1151.
Liu, J. Inorg. Biochem. 2018, 189, 163.
[40] J. Li, M. Tian, Z. Tian, S. Zhang, C. Yan, C. Shao, Z. Liu, Inorg.
Chem. 2018, 57, 1705.
[19] J. Hess, H. Huang, A. Kaiser, V. Pierroz, O. Blacque, H. Chao,
G. Gasser, Chem. Eur. J. 2017, 23, 9888.
[41] H. Guan, M. Iimura, M. P. Magee, J. R. Norton, K. E. Janak,
[20] J. M. Rademaker‐Lakhai, D. van den Bongard, D. Pluim, J. H.
Beijnen, J. H. M. Schellens, Clin. Cancer Res. 2004, 10, 3717.
Organometallics 2003, 22, 4084.
[42] F. Zhang, X. Xu, Y. Zhao, J. Jia, C. H. Tung, W. Wang, Organ-
ometallics 2017, 36, 1238.
[21] C. G. Hartinger, M. A. Jakupec, S. Zorbas‐Seifried, M. Groessl,
A. Egger, W. Berger, H. Zorbas, P. J. Dyson, B. K. Keppler,
Chem. Biodiversity 2008, 5, 2140.
[43] M. Ganeshpandian, R. Loganathan, E. Suresh, A. Riyasdeen,
M. A. Akbarsha, M. Palaniandavar, Dalton Trans. 2014, 43,
1203.
[22] L. Rajendran, H. J. Knölker, K. Simons, Nat. Rev. Drug Discov.
2010, 9, 29.
[44] R. E. Aird, J. Cummings, A. A. Ritchie, M. Muir, R. E. Morris,
[23] H. Xia, G. Gu, Q. Hu, Z. Liu, M. Jiang, T. Kang, D. Miao, Q.
Song, L. Yao, Y. Tu, H. Chen, X. Gao, J. Chen, Bioconjugate
Chem. 2013, 24, 419.
H. Chen, P. J. Sadler, D. I. Jodrell, Br. J. Cancer 2002, 86, 1652.
[45] Y. Zhao, J. Jin, Q. Hu, H. M. Zhou, J. Yi, Z. Yu, L. Xu, X. Wang,
Y. Yang, J. Loscalzo, Cell Metab. 2011, 14, 555.
[24] W. Ma, Z. Tian, S. Zhang, X. He, J. Li, X. Xia, X. Chen, Z. Liu,
Inorg. Chem. Front. 2018, 5, 2587. https://doi.org/10.1039/
C8QI00620B
[46] L. Zhe, R. C. Isolda, Q. Bushra, H. J. M. H. Abraha, N. P. E.
Barry, A. M. Pizarro, G. J. Clarkson, P. Sadler, Angew. Chem.
Int. Edit. 2014, 53, 3941.
[25] N. M. Sakhrani, H. Padh, Drug Des. Devel. Ther. 2013, 7, 585.
[47] R. Blomgran, L. Zheng, O. Stendahl, J. Leukocyte Biol. 2007, 81,
[26] Z. Feng, H. Wang, S. Wang, Q. Zhang, X. Zhang, A. A. Rodal,
1213.
B. Xu, J. Am. Chem. Soc. 2018, 140, 9566.
[48] L. Liu, Z. Zhang, D. Xing, Free Radical Biol. Med. 2011, 51, 53.
[27] Z. Xu, D. Kong, X. He, L. Guo, X. Ge, X. Liu, H. Zhang, J. Li, Y.
[49] L. He, Y. Li, C. P. Tan, R. R. Ye, M. H. Chen, J. J. Cao, L. N. Ji,
Yang, Z. Liu, Inorg. Chem. Front. 2018, 5, 2100.
Z. W. Mao, Chem. Sci. 2015, 6, 5409.
[28] J. Liu, C. Jin, B. Yuan, X. Liu, Y. Chen, L. Ji, H. Chao, Chem.
Commun. 2017, 53, 2052.
[50] N. Li, L. Yu, J. Wang, X. Gao, Y. Chen, W. Pan, B. Tang, Chem.
Sci. 2018, 9, 3159.
[29] U. Repnik, V. Stoka, V. Turk, B. Turk, BBA Proteins Proteom.
2012, 1824, 22.
[51] L. Li, Y. S. Wong, T. Chen, C. Fan, W. Zheng, Dalton Trans.
2012, 41, 1138.
[30] N. H. T. Petersen, O. D. Olsen, L. Groth‐Pedersen, A.‐M.
Ellegaard, M. Bilgin, S. Redmer, M. S. Ostenfeld, D. Ulanet,
T. H. Dovmark, A. Lønborg, S. D. Vindeløv, D. Hanahan, C.
Arenz, C. S. Ejsing, T. Kirkegaard, M. Rohde, J. Nylandsted,
M. Jäättelä, Cancer Cell 2013, 24, 379.
[52] V. Pierroz, T. Joshi, A. Leonidova, C. Mari, J. Schur, I. Ott, L.
Spiccia, S. Ferrari, G. Gasser, J. Am. Chem. Soc. 2012, 134,
20,376.
[53] M. Galanski, M. A. Jakupec, B. K. Keppler, Curr. Med. Chem.
2005, 12, 2075.
[31] A. Habtemariam, M. Melchart, R. Fernández, S. Parsons, I. D.
H. Oswald, A. Parkin, F. P. A. Fabbiani, J. E. Davidson, A.
Dawson, R. E. Aird, D. I. Jodrell, P. J. Sadler, J. Med. Chem.
2006, 49, 6858.
[54] C. Wang, J. Liu, Z. Tian, M. Tian, L. Tian, W. Zhao, Z. Liu,
Dalton Trans. 2017, 46, 6870.
[32] Z. Tian, J. Li, S. Zhang, Z. Xu, Y. Yang, D. Kong, H. Zhang, X.
SUPPORTING INFORMATION
Ge, J. Zhang, Z. Liu, Inorg. Chem. 2018, 57, 10,498.
Additional supporting information may be found online
in the Supporting Information section at the end of the
article.
[33] D. Kong, M. Tian, L. Guo, X. Liu, S. Zhang, Y. Song, X. Meng,
S. Wu, L. Zhang, Z. Liu, J. Biol. Inorg. Chem. 2018, 23, 819.
[34] Y. Sun, J. Yu, X. Liu, C. Zhang, J. Cao, G. Li, X. Liu, Y. Chen,
H. Huang, Biomed. Pharmacother. 2018, 102, 699.
[35] G. Gasser, I. Ott, N. Metzler‐Nolte, J. Med. Chem. 2011, 54, 3.
How to cite this article: Li JJ, Tian Z, Zhang S,
et al. Organometallic ruthenium and iridium
phosphorus complexes: Synthesis, cellular imaging,
organelle targeting and anticancer applications.
Appl Organometal Chem. 2019;e4685. https://doi.
org/10.1002/aoc.4685
[36] C. G. Hartinger, N. Metzler‐Nolte, P. J. Dyson, Organometallics
2012, 31, 5677.
[37] Q. Du, L. Guo, M. Tian, X. Ge, Y. Yang, X. Jian, Z. Xu, Z. Tian,
Z. Liu, Organometallics 2018, 37, 2880.
[38] J. Li, L. Guo, Z. Tian, M. Tian, S. Zhang, K. Xu, Y. Qian, Z. Liu,
Dalton Trans. 2017, 46, 15,520.