P-donor ligand containing ruthenium half-sandwich complexes as protein kinase inhibitors

Article abstract of DOI:10.1016/j.ica.2011.07.032

Metal complexes have emerged as promising and novel scaffolds for the design of enzyme inhibitors. Reported herein are the design, synthesis, and evaluation of protein kinase inhibition properties of pyridocarbazole half-sandwich complexes containing P-do

Full text of DOI:10.1016/j.ica.2011.07.032

Inorganica Chimica Acta 377 (2011) 34–41
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Inorganica Chimica Acta
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P-donor ligand containing ruthenium half-sandwich complexes as protein
kinase inhibitors
Craig Streu a, Li Feng b, Patrick J. Carroll a, Jasna Maksimoska a,c, Ronen Marmorstein a,c, Eric Meggers a,b,
⇑
a Department of Chemistry, University of Pennsylvania, 231 S., 34th Street, Philadelphia, PA 19104, USA
b Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043 Marburg, Germany
c The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
Metal complexes have emerged as promising and novel scaffolds for the design of enzyme inhibitors.
Reported herein are the design, synthesis, and evaluation of protein kinase inhibition properties of pyri-
docarbazole half-sandwich complexes containing P-donor ligands. The nature of the monodentate P-
donor ligand has a strong effect on protein kinase binding properties, most likely due to a direct interac-
tion with the glycine-rich loop in the ATP-binding site. We furthermore discovered that PMe3 pyridocar-
bazole complexes are interesting lead structures for the design of potent inhibitors for the protein kinase
TrkA for which we obtained a nanomolar organometallic inhibitor.
Received 22 April 2011
Received in revised form 15 July 2011
Accepted 20 July 2011
Available online 30 July 2011
Keywords:
Metal-based drugs
Protein kinases
Inhibitors
Ó 2011 Elsevier B.V. All rights reserved.
Phosphine ligands
Ruthenium
1. Introduction
For example, we recently reported the promising kinase inhibi-
tion and anticancer effects of the metallo-pyridocarbazole complex
The unique properties of metal complexes such as structural
diversity, adjustable ligand exchange kinetics, fine-tuned redox
activities, and distinct spectroscopic signatures, render them excit-
ing scaffolds for the design of synthetic compounds with novel bio-
logical properties [1]. However, surprisingly, metal-containing
compounds play only a minor role in the design of molecular
probes for chemical biology or as drug candidates in the pharma-
ceutical industry [2].
Several years ago we initiated a research program to explore
substitutionally inert metal complexes as scaffolds for the design
of enzyme inhibitors [3]. Our program is based on the hypothesis
that complementing organic elements with typical coordination
modes of transition metals such as octahedral or half-sandwich
coordination spheres will provide new opportunities for building
small molecule structures that might populate unique chemical
space which cannot be accessed by purely organic compounds
[4]. We primarily focus on metals such as ruthenium, osmium, rho-
dium, and iridium which are capable of forming kinetically highly
stable complexes that are uncompromised in biological environ-
ments and should therefore serve as ideal structural metal centers
in stable bioactive metal complexes.
DW12 and some of its derivatives (Fig. 1) [5–8]. The ruthenium
half-sandwich complex DW12 is a very selective and potent inhib-
itor for the protein kinases GSK3 and Pim1 which induces strong
biological responses, such as the activation of the Wnt signaling
pathway in mammalian cells, strong pharmacological effects dur-
ing the development of frog embryos, and the efficient induction
of apoptosis in some melanoma cell lines. A crystal structure of
(R)-DW12 bound to the ATP-binding site of GSK3b provides insight
into the important role of the CO ligand for binding affinity of (R)-
DW12 to GSK3b [9]: several residues of the glycine-rich-loop –
which closes like a lid on top of the inhibitor upon binding – form
a small hydrophobic pocket via induced fit that appears perfectly
suited for the CO ligand. The unique shape of the organometallic
scaffold with the CO ligand oriented perpendicular to the heteroar-
omatic pyridocarbazole moiety allows the glycine-rich loop to
adopt a very close conformation with maximized hydrophobic con-
tacts. This is consistent with our experimental results for this and
related organometallic complexes, which demonstrate the impor-
tance of the CO group for GSK3 potency and selectivity. Interest-
ingly, published and yet unpublished results accumulated over
the last several years suggest that the interaction of different
monodentate ligands with the glycine-rich loop can alter protein
kinase binding affinity and selectivity significantly [3,10]. This
observation is potentially of high relevance since the human gen-
ome codes for around 500 protein kinases [11], which all contain
⇑
Corresponding author at: Fachbereich Chemie, Philipps-Universität Marburg,
Hans-Meerwein-Straße, 35043 Marburg, Germany.
E-mail address: meggers@chemie.uni-marburg.de (E. Meggers).
0020-1693/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2011.07.032

C. Streu et al. / Inorganica Chimica Acta 377 (2011) 34–41
35
a)
Scheme 1. Single-pot procedure for the synthesis of the racemic phosphine
complex 3.
b)
Fig. 1. (a) Binding of the half sandwich complex (R)-DW12 to the ATP-binding site
of a protein kinase. (b) Changing the kinase inhibition properties by replacing the
CO ligands of HB12 (R = H) or DW12 (R = OH) with monodentate P-donor ligands.
Only one enantiomer of the CO and PR03 complexes are shown.
a highly conserved ATP-binding site, making the design of selective
protein kinase inhibitors an extraordinary challenge.
Herein we report the design, synthesis and protein kinase inhi-
bition properties of new organometallic protein kinase inhibitors
obtained by replacing the CO ligand of our canonical metallo-pyri-
docarbazole scaffold by monodentate P-donor ligands.
Fig. 2. Crystal structure of PMe3 complex 3. ORTEP drawing with 30% probability
thermal ellipsoids. Selected bonds distances (Å) and angles (°): Ru1–P1 = 2.2930(9),
Ru1–N2 = 2.102(3), Ru1–N19 = 2.140(3), N2–Ru1–N19 = 77.96(10), N2–Ru1–
P1 = 86.80(8), and N19–Ru1–P1 = 89.42(8).
2. Results and discussion
We started by developing a synthetic route for accessing pyri-
docarbazole ruthenium half-sandwich complexes bearing mono-
dentate P-donor ligands. The reaction of [CpRu(CH3CN)3]PF6 (1)
[12] with the bidentate pyridocarbazole ligand 2 [13] in the pres-
ence of K2CO3 in MeCN/MeOH 4:1, followed in situ by the addition
of PMe3 afforded the ruthenium half-sandwich complex 3 in this
one-pot procedure with a yield of 83% (Scheme 1). Complex 3 is
hydrolytically stable. For example, no degradation could be ob-
served by 1H NMR after three days in DMSO-d6 and methanol-d4.
The crystal structure of complex 3 is shown in Fig. 2 and confirms
the half-sandwich structure of the complex. Crystallographic data
are displayed in Table 1. The PMe3 group is oriented almost per-
pendicular to the plane of the pyridocarbazole heterocycle as ex-
pected for a pseudo-octahedral coordination sphere. However,
the phosphine ligand is slightly bent towards the pyridocarbazole
heterocycle as can be seen from the bond angles N2–Ru1–
P1 = 86.80° and N19–Ru1–P1 = 89.42° (Fig. 2). This might be an
important detail since it is most likely this phosphine ligand that
interacts with the glycine-rich loop of the ATP-binding site of pro-
tein kinases upon binding.
Encouraged by these results, we next synthesized complexes
with different P-donor ligands in combination with an unprotected
maleimide moiety in order to be able to form important canonical
hydrogen bonds to the hinge region of the ATP-binding site.
Accordingly, precursor complex 1 was reacted first with tert-butyl-
dimethylsilyl (TBS)-protected pyridocarbazole 4 [14] in CH2Cl2 at
0 °C in the presence of (ꢀ)-sparteine after which the P-ligands
PMe3, PEt3, P(CH2OH)3, P(OMe)3, or PF3 were added to provide
complexes 5a–e, followed by removal of the TBS-group with tetra-
butylammoniumfluoride (TBAF) to yield complexes 6a (PMe3), 6b
(PEt3), 6c (P(CH2OH)3), 6d (P(OMe)3), and 6e (PF3) (Scheme 2). In
these reactions, (ꢀ)-sparteine gave better results than either
K2CO3 or Et3N. All complexes were purified by flash silica gel chro-
matography. Interestingly, the monodentate ligands have a pro-
found influence on the electronic properties of the ruthenium
center as indicated by the different colors of the complexes 6a,

36
C. Streu et al. / Inorganica Chimica Acta 377 (2011) 34–41
Table 1
Crystallographic data for complex 3.
Formula
C32H28N3PO2Ru
Formula weight
Crystal class
Space group
Z
618.61
triclinic
ꢀ
P1 (#2)
2
Cell constants
a (Å)
b (Å)
7.9943(7)
10.5921(9)
16.772(2)
105.989(3)
91.311(2)°
98.649(2)°
1346.7(2)
6.77
c (Å)
a
(°)
b (°)
(°)
V (Å3)
(cmꢀ1
c
l
)
Crystal size (mm)
Dcalc (g cm3)
F(0 0 0)
Radiation
2h Range (°)
hkl Collected
0.40 ꢁ 0.15 ꢁ 0.04
1.526
632
Fig. 3. The different colors of diluted DMSO solutions (100 lM) of the P-ligand
Mo Ka (k = 0.71073 Å)
5.06–50.04
complexes 6a (kmax = 628 nm), 6d (kmax = 585 nm), and 6e (kmax = 525 nm) demon-
strate the different electronic properties of the P-donor ligands. The color of the CO-
containing complex HB12 (kmax = 535 nm) is shown as a reference. Values for the
long-wavelength absorbance maxima are provided in brackets.
ꢀ9 6 h 6 8; ꢀ12 6 k 6 12;
ꢀ19 6 l 6 19
Number of reflections measured
Number of unique reflections
Number of observed reflections
Number of reflections used in
refinement
10 950
4716 (Rint = 0.0262)
4216 (F > 4r)
4716
100
80
60
40
20
0
Number of parameters
356
R1 = 0.0408
wR2 = 0.1039
R1 = 0.0459
wR2 = 0.1087
1.063
R indices (F > 4
r)
R indices (all data)
Goodness-of-fit (GOF)
Final difference peaks (eÅ3)
+1.409, ꢀ0.787
TBS
1.)
N
O
O
TBS
N
6a
6b
6c
6d
6e
O
O
P-Ligand Complexes (10 μM)
N
N
Fig. 4. Inhibition of the protein kinase PAK1 by the P-donor ligand complexes 6a–e
at a concentration of 10 M and an ATP concentration of 1 M. The bars represent
remaining kinase activities under these conditions.
H
4
l
l
(-)-sparteine
CH2Cl2, 0 °C
N
N
[η5-CpRu(MeCN)3]PF6
Ru
2.) PR3
Since the phosphine ligands are sterically more demanding than
the CO ligands of the previous inhibitors DW12 and HB12 (Fig. 1),
among others, we decided to initially test the complexes 6a–e as
inhibitors for the p21-activated protein kinase 1 (PAK1). PAK1 is
distinguished by an especially large ATP binding site which is
therefore capable of accommodating more bulky inhibitors [15].
Fig. 4 displays the remaining enzymatic activity of PAK1 in the
1
R3P
5a-e
TBAF,
CH2Cl2
H
N
presence of 10 lM of the individual P-donor ligand complexes
O
O
6a–e. Importantly, the bar diagram demonstrates that the mono-
dentate ligands have a profound effect on the inhibition of PAK1.
For example, complex 6b (100% remaining activity) does not affect
the enzymatic activity of PAK1. This is apparently due to the bulk-
iness of the PEt3 ligand, which prevents the complex from binding
to the ATP-binding site altogether. A related steric effect can ex-
plain the weak inhibitory activity of the P(OMe)3 complex 6d
(79% remaining PAK1 activity), whereas the inactivity of the PF3-
complex 6e (89% remaining PAK1 activity) might be rationalized
by an unfavorable interaction of the fluoride ligands with hydro-
phobic residues of the glycine-rich loop. On the other hand, the
small and hydrophobic PMe3 group of complex 6a results in a sig-
5a, 6a: PMe3
5b, 6b: PEt3
5c, 6c: P(CH2OH)3
5d, 6d: P(OMe)3
5e, 6e: PF3
N
N
Ru
R3P
Scheme 2. Synthesis of the racemic P-ligand complexes 6a–e. See experimental
section for individual yields.
6d, and 6e shown in Fig. 3. As one would expect, complex 6e bear-
nificant inhibition of PAK1 at 10 lM (46% activity). Surprisingly,
ing a
p-acceptor PF3 ligand comes the closest in color to the solu-
complex 6c bearing the P(CH2OH)3 ligand displays the strongest
tion of HB12 (Fig. 1) harboring a
p-accepting CO ligand.
inhibitory properties (21% remaining PAK1 activity). Apparently

C. Streu et al. / Inorganica Chimica Acta 377 (2011) 34–41
37
one or more of the OH-groups are involved in additional hydrogen
bonds within the ATP binding site of PAK1.
In order to gain additional information about the kinase inhibi-
tion properties of this class of P-donor ligand ruthenium half-sand-
wich complexes, we selected compound 6a and screened it against
a panel of 263 protein kinases. As a result, at a concentration of
Based on a previous study towards the design of TrkA inhibitors
[17], we envisioned that complexes such as 7 and 8, differing from
6a by a fused benzene ring at the pyridine moiety and an addi-
tional OH-group at the indole 5-position as in 8, might provide im-
proved TrkA inhibitors (Scheme 3). Complexes 7 and 8 were
synthesized in analogy to 6a–e by the reaction of ruthenium pre-
cursor complex 1 with TBS-protected pyridocarbazole 9a [14] or
9b [17] in the presence of a tertiary amine base, with subsequent
addition of PMe3, followed by a TBS-deprotection with TBAF. As ex-
pected, the isoquinoline complex 7 shows an improved IC50 value
(concentration of inhibitor at which the enzyme activity is reduced
1 lM 6a and 10 lM ATP most protein kinases were not affected
by complex 6a. For example, as shown in the bar diagram of
Fig. 5, 103 kinases retained more than 90% of their activities and
197 out of the 263 kinases remained more than 50% active under
these conditions. However, the three protein kinases GSK3
Pim1, and TrkA were almost completely inhibited in the presence
of 1 M of 6a (<5% activity). Neurotrophic tyrosine kinase receptor
a,
to 50%) of 35 nM compared to an IC50 of >1
lM for 6a at the ele-
l
vated ATP concentration of 100 M. Additionally, the inclusion of
l
type 1 (TrkA), is the high affinity receptor for the nerve growth fac-
tor (NGF) [16]. NGF-activated TrkA can promote cell proliferation
or differentiation of neurons. Mutations in the gene for TrkA have
been associated with several diseases such as mental retardation
and cancer. We therefore selected TrkA as a target to design more
potent phosphine-based ruthenium inhibitors.
an OH-group at the 5-position of the indole increases the affinity
further, rendering complex 8 a highly potent, nanomolar inhibitor
for TrkA with an IC50 of 23 nM at 100 lM ATP.
3. Conclusions
In conclusion, we have herein reported the design, synthesis
and protein kinase inhibition properties of P-donor ligand contain-
ing pyridocarbazole half-sandwich complexes. As expected, the
nature of the monodentate P-donor ligand has a strong effect on
protein kinase binding data, most likely due to a direct interaction
with the glycine-rich loop in the ATP-binding site. Finally, we dis-
covered that PMe3 pyridocarbazole complexes are suitable lead
structures for the design of potent TrkA inhibitors and we demon-
strated this with the design of a nanomolar inhibitor for TrkA. This
work demonstrates that metal complexes are highly suitable struc-
tural scaffolds for the design of enzyme inhibitors by using the
coordination sphere around the metal center to provide great con-
trol over the orientation of ligands within the enzyme active site.
Further exploitation of this efficient methodology using novel P-
donor ligands may yield potent inhibitors of still new kinases by
utilizing otherwise inaccessible regions of chemical space.
110
100
90
80
70
60
50
40
30
20
10
0
<5% 5-10% 11-30% 31-50% 51-70% 71-90% >90%
Kinase Activity at 1 μM 6a
Fig. 5. Selectivity profile of PMe3 complex 6a in a panel of 263 protein kinases.
Activities were determined by Millipore (KinaseProfiler) at a concentration of
4. Experimental
10
lM ATP. Remaining activities are mean values from duplicate measurements.
4.1. Materials and methods
Under these conditions, only three protein kinases show an activity of less than 5%
(TrkA, Pim1, GSK3a).
Compounds 1 [12], 2 [13], 4 [14], 9a [14], and 9b [17] were pre-
pared according to literature procedures. All solvents and reagents
were used as supplied from Aldrich, Acros, Strem, and Fisher Scien-
tific. Reactions were performed in oven-dried glassware under an
atmosphere of argon unless otherwise noted. Silicycle (250 lm,
indicator F254) plates were used for thin layer chromatography
and Silia-P Flash silica gel from Silicycle was used for flash chroma-
tography. NMR spectra were recorded on
a Bruker AM-500
(500 MHz), DMX-360 (360 MHz), cryo500 (500 MHz), or DMX-
300 (300 MHz) spectrometer. NMR standards used are as follows:
(1H) CDCl3 = 7.26 ppm, CD3OD = 3.31 ppm, (CD3)2SO = 2.49 ppm,
(CD3)2CO = 2.05 ppm, CD3CN = 1.94 ppm. (13C) CDCl3 = 77.23 ppm,
(CD3)2SO = 39.51 ppm, CD3CN = 1.32 ppm. High-resolution mass
spectra were obtained at the University of Pennsylvania Mass
Spectrometry Facility with a Micromass AutoSpec instrument
using either chemical or electrospray ionization or with a Waters
LCT Premier instrument using electrospray ionization and a TOF
analyzer. Infrared spectra were recorded on a Perkin–Elmer 1600
FTIR spectrometer.
3
2
2
3
3
50
4.2. Protein kinase assays
50
PAK1 was expressed and purified as described elsewhere [15].
TrkA and kinase substrates were purchased from Millipore.
Scheme 3. Synthesis of the racemic TrkA inhibitor 7 and 8. IC50 values against TrkA
are shown at 100 M ATP.
l

38
C. Streu et al. / Inorganica Chimica Acta 377 (2011) 34–41
4.2.1. PAK1 assays
dark green band (59.0 mg, 83%). 1H NMR (500 MHz, CDCl3): d
Kinase assays were performed using labeled [
c-
32P]-ATP and
(ppm) 9.00 (m, 2H, Ar), 8.89 (d, J = 7.9, 1H, Ar), 7.56 (m, 4H, Ar),
7.40–7.32 (m, 4H, Ar), 7.25 (t, J = 7.3, 1H, Ar), 4.96 (s, 2H, NCH2–
C6H5), 4.59 (s, 5H, C5H5), 0.75 (s, 9H, P(CH3)3). 31P NMR
the incorporation of P32-phosphate into the myelin basic protein
(MBP) substrate was monitored. Different concentrations of the
inhibitors were incubated with 0.2 nM PAK1 kinase in 20 mM
(122 MHz, CDCl3): d (ppm) 7.1. IR (film):
m
(cmꢀ1) 3054, 2969,
MOPS pH 7.0, 30 mM MgCl2, 0.8
and 5% DMSO (resulting from the inhibitor stock solution) in the
presence of 25 g of MBP substrate for 15 min. Reactions were ini-
tiated by adding ATP to a final concentration of 1 M including
0.2 Ci/ L[ L. The reactions
32P] ATP in a final volume of 25
were terminated by spotting 17.5 L onto circular P81 phosphocel-
lulose paper (diameter 2.1 cm, Whatman), followed by washing
three times with 0.75% phosphoric acid and one time with acetone.
The dried P81 papers were transferred to scintillation vials and
4 mL of scintillation cocktail was added. The counts per minute
(CPM) were measured in a Packard 1500 Tri-Carb Liquid Scintilla-
tion Analyzer.
l
g/
l
L bovine serum albumin
2925, 1744 (C@O), 1691 (C@O), 1579, 1525, 1491, 1415, 1386,
1348, 1262, 1229, 1135, 1100, 1076, 946, 746.
l
l
4.3.2. Compound 5a
l
l
c-
l
To an argon saturated solution of CH2Cl2 (3 mL) at 0 °C, was
added ligand 4 (14.3 mg, 0.034 mmol) and precursor complex 1
(15.0 mg, 0.034 mmol) to give a dark solution. After stirring
l
5 min at 0 °C, (ꢀ)-sparteine (10.3
ing the reaction to become dark purple. After stirring for 45 min at
0 °C, PMe3 (31.8 L, 0.306 mmol) was added and the reaction was
lL, 0.045 mmol) was added caus-
l
allowed to warm slowly to room temperature. After 1 h, the green
reaction was concentrated and subjected to flash chromatography
over silica gel with a toluene:acetone (50:1) mobile phase. The
product 5a eluted as a dark green band (14.0 mg, 63%). 1H NMR
(500 MHz, CDCl3): d (ppm) 9.06 (d, J = 8.3 Hz, 1H, Ar), 9.02 (d,
J = 4.6 Hz, 1H, Ar), 8.89 (d, J = 7.8 Hz, 1H, Ar), 7.54 (m, 2H, Ar),
7.36 (m, 2H, Ar), 4.60 (s, 5H, C5H5), 1.07 (s, 9H, C(CH3)3), 0.77 (br
s, 9H, P(CH3)3), 0.62 (s, 6H, Si(CH3)2). 13C NMR (125 MHz, CDCl3):
d (ppm) 175.9 (C@O), 175.8 (C@O), 154.7, 153.6, 152.4, 145.2,
132.5, 131.3, 125.6, 125.2, 124.5, 122.1, 121.6, 119.7, 115.9,
115.1, 113.3, 72.6 (C5H5), 26.8 (SiC(CH3)3), 19.4 (C(CH3)3), 17.9 (d,
JC–P = 24 Hz, P(CH3)3), ꢀ3.6 (Si(CH3)2). 31P NMR (122 MHz, CDCl3):
4.2.2. TrkA assays with [c-
32P]ATP
Various concentrations of the measured complexes were incu-
bated at room temperature in 20 mM MOPS, 30 mM MgCl2,
0.8
tion), pH 7.0, in the presence of 250
NIEFG and 8.0 nM TrkA. After 15 min, the reaction was initiated
by adding ATP to a final concentration of 100 M, including
approximately 0.2 Ci/ L [
32P]ATP. Reactions were performed
in a total volume of 25 L and incubated at 30 °C. After 45 min,
the reaction was terminated by spotting 17.5 L on a circular
lg/
lL BSA, 5% DMSO (resulting from the inhibitor stock solu-
lM Trk peptide KKKSPGEYV-
l
l
l
c-
l
l
d (ppm) 7.4. IR (film): m
(cmꢀ1) 2923, 2854, 1676 (C@O), 1587,
P81 phosphocellulose paper (2.1 cm diameter, Whatman), fol-
lowed by washing four times with 0.75% phosphoric acid and once
with acetone. The dried P81 papers were transferred to a scintilla-
tion vial, 5 mL of scintillation cocktail was added, and the CPM
were determined with a Beckmann 6000 scintillation counter.
IC50 values were defined to be the concentration of inhibitor at
which the CPM was 50% of the control sample, corrected by the
background.
1497, 1424, 1399, 1299, 1270, 1219, 1114, 1062, 970, 892, 783,
734. HRMS calcd for C31H37N3O2PRuSi (M+H)+ 644.1431, found
(M+H)+ 644.1442.
4.3.3. Compound 6a
TBS-protected complex 5a (12 mg, 0.018 mmol) was taken up in
dry CH2Cl2 (1.5 mL). To this green solution was added a 1.0 M solu-
tion of TBAF in THF (27.5 lL, 0.027 mmol) causing the reaction to
immediately become purple. After stirring for 40 min, the reaction
was quenched by exposing it to acetic acid vapor. The reaction was
then concentrated and subjected to flash chromatography over sil-
ica gel with a toluene:acetone 25:1 mobile phase. The product 6a
eluted as a dark green band (9.6 mg, 99%). 1H NMR (360 MHz,
CDCl3): d (ppm) 9.03 (m, 2H, Ar), 8.86 (dt, J = 7.9, 1.0 Hz, 1H, Ar),
7.58 (m, 2H, Ar), 7.45 (br s, 1H, NH), 7.43–7.36 (m, 2H, Ar), 4.61
(s, 5H, C5H5), 0.77 (d, JH–P = 8.8 Hz, 9H, P(CH3)3). 13C NMR
(90 MHz, CDCl3): d (ppm) 170.2 (C@O), 170.2 (C@O), 155.0, 153.8,
152.4, 144.9, 130.9, 126.1, 125.1, 124.5, 122.5, 121.9, 121.9,
120.0, 116.0, 115.8, 110.8, 72.7 (C5H5), 17.9 (d, JC–P = 26 Hz,
4.2.3. TrkA assays with [c-
33P]ATP
Various concentrations of ruthenium complexes were incu-
bated at room temperature in 10 mM MOPS, 10 mM Mg(OAc)2,
0.1
tion), pH 7.0, in the presence of 100
NIEFG and 10 nM TrkA. After 15 min, the reaction was initiated
by adding ATP to a final concentration of 100 M, including
approximately 0.06 Ci/ L [
33P]ATP. Reactions were performed
in a total volume of 25 L. After 2 h, the reaction was terminated
by spotting 15 L on a circular P81 phosphocellulose paper
lg/
lL BSA, 5% DMSO (resulting from the inhibitor stock solu-
l
M Trk peptide KKKSPGEYV-
l
l
l
c-
l
l
(2.1 cm diameter, Whatman), followed by washing three times
with 0.75% phosphoric acid and once with acetone. The dried P81
papers were transferred to a scintillation vial, 5 mL of scintillation
cocktail was added, and the CPM was determined with a Beckmann
6000 scintillation counter.
P(CH3)3). IR (film):
(C@O), 1575, 1496, 1468, 1416, 1344, 1280, 1260, 1224, 1152,
m
(cmꢀ1) 2963, 2915, 2843, 1743 (C@O), 1695
1097, 1021, 949. HRMS calcd for
C
25H23N3O2PRu (M+H)+
530.0566, found (M+H)+ 530.0573.
4.3.4. Compound 5b
4.3. Compound preparation
To an argon saturated solution of CH2Cl2 (3 mL) at 0 °C, was
added ligand 4 (10.0 mg, 0.025 mmol) and precursor complex 1
(11.3 mg, 0.026 mmol) to give a dark solution. After stirring
4.3.1. Compound 3
To an argon saturated solution of CH3CN:MeOH 4:1 (5 mL) at
5 min at 0 °C, (ꢀ)-sparteine was added (6.9
ing the reaction to become dark purple. After stirring for 30 min at
0 °C, PEt3 (11.0 L, 0.075 mmol) was added and the reaction was
allowed to warm slowly to room temperature. After 1 h, the green
reaction was concentrated and subjected to flash chromatography
over silica gel with a toluene:acetone 50:1 mobile phase. The prod-
uct 5b eluted as a dark green band (9.6 mg, 56%). 1H NMR
(360 MHz, CDCl3): d (ppm) 9.06 (d, J = 7.5 Hz, 1H, Ar), 9.05 (d,
J = 7.4 Hz, 1H, Ar), 8.90 (ddd, J = 7.9, 1.2, 0.8 Hz, 1H, Ar), 7.62 (d,
J = 8.1 Hz, 1H, Ar), 7.54 (m, 1H, Ar), 7.39–7.33 (m, 2H, Ar), 4.58 (s,
lL, 0.030 mmol) caus-
0 °C, was added benzyl protected pyridocarbazole ligand
2
(43.4 mg, 0.115 mmol) and complex 1 (50.0 mg, 0.115 mmol) to
give a dark red solution. After stirring 5 min at 0 °C, K2CO3 was
added (47.6 mg, 0.345 mmol) causing the reaction to become dark
l
purple. After stirring for 45 min at 0 °C, PMe3 (35.7 lL,
0.345 mmol) was added and the reaction was allowed to warm
slowly to room temperature. After 1 h, the reaction was concen-
trated and subjected to flash chromatography over silica gel with
a 35:1 toluene:acetone mobile phase. The product 3 eluted as a

C. Streu et al. / Inorganica Chimica Acta 377 (2011) 34–41
39
5H, C5H5), 1.07 (s, 9H, C(CH3)3), 1.00 (m, 6H, P(CH2CH3)3), 0.78 (m,
4.3.7. Compound 5d
9H, P(CH2CH3)3), 0.62 (s, 3H, SiCH3), 0.61 (s, 3H, SiCH3). 13C NMR
(90 MHz, CDCl3): d (ppm) 175.9 (C@O), 175.8 (C@O), 155.0,
153.9, 152.6, 145.5, 132.5, 131.4, 125.5, 125.1, 124.6, 122.0,
121.6, 119.6, 116.0, 115.3, 113.1, 72.4 (C5H5), 26.8 (SiC(CH3)3),
19.4 (SiC(CH3)3), 17.4 (d, JC–P = 23 Hz, P(CH2CH3)3), 7.6
To an argon saturated solution of CH2Cl2 (3 mL) at 0 °C, was
added ligand 4 (17.4 mg, 0.0419 mmol) and precursor complex 1
(20.0 mg, 0.046 mmol) giving a dark solution. After stirring 5 min
at 0 °C, (ꢀ)-sparteine was added (13.8
the reaction to become dark purple. After stirring for 30 min at
0 °C, P(OMe)3 (16.3 L, 0.138 mmol) was added and the reaction
lL, 0.060 mmol) causing
(P(CH2CH3)3), ꢀ3.6 (Si(CH3)2). IR (film):
m
(cmꢀ1) 2957, 2930,
l
2852, 1742 (C@O), 1683 (C@O), 1579, 1520, 1495, 1470, 1415,
1338, 1319, 1280, 1259, 1227, 1189, 1174, 1127, 1039, 848, 828,
747, 732. HRMS calcd for C34H42N3O2PRuSi (M)+ 685.1827, found
(M)+ 685.1805.
was allowed to warm slowly to room temperature. After 2 h, the
reaction was concentrated and subjected to flash chromatography
over silica gel with toluene:acetone 50:1. The product 5d eluted as
a dark purple band (10.5 mg). Some TBS-deprotected material 6d
could be eluted as a more polar purple band (1.0 mg) resulting in
an overall yield of 43%. 1H NMR (360 MHz, CDCl3): d (ppm) 9.12
(d, J = 8.1 Hz, 1H, Ar), 9.06 (d, J = 5.2 Hz, 1H, Ar), 8.90 (dt, J = 7.9,
1.1 Hz, 1H, Ar), 7.60 (d, J = 8.2 Hz, 1H, Ar), 7.54 (ddd, J = 8.2, 6.9,
1.3 Hz, 1H, Ar), 7.37 (m, 2H, Ar), 4.81 (s, 5H, C5H5), 3.13, (d,
J = 11.3 Hz, 9H, P(OCH3)3), 1.07 (s, 9H, SiC(CH3)3), 0.62 (s, 6H,
Si(CH3)2). 13C NMR (90 MHz, CDCl3): d (ppm) 175.9 (C@O), 175.6
(C@O), 155.4, 154.1, 153.8, 145.7, 132.7, 132.4, 125.6, 125.2,
124.5, 121.9, 121.6, 119.6, 115.9, 115.4, 113.5, 75.5 (C5H5), 51.2
(OCH3), 26.8 (SiC(CH3)3), 19.4 (SiC(CH3)3), ꢀ3.6 (Si(CH3)2). 31P
4.3.5. Compound 6b
TBS protected complex 6b (9.6 mg, 0.014 mmol) was taken up
in dry CH2Cl2 (1.5 mL). To this was added a 1.0 M solution of TBAF
in THF (42 lL, 0.042 mmol) causing the reaction to immediately
turn purple. After stirring at room temperature for 5 min, the reac-
tion was quenched by exposing it to acetic acid vapor. The reaction
was then concentrated and subjected to flash chromatography
over silica gel with toluene:acetone (50:1). The product 6b eluted
as a dark green band (8.0 mg, quant.). 1H NMR (500 MHz, DMSO-
d6): d (ppm) 10.89 (s, 1H, NH), 9.35 (d, J = 5.2 Hz, 1H, Ar), 8.86 (d,
J = 8.3 Hz, 1H, Ar), 8.64 (d, J = 7.9 Hz, 1H, Ar), 7.68 (d, J = 8.2 Hz,
1H, Ar), 7.57 (dd, J = 8.4, 5.1 Hz, 1H, Ar), 7.50 (t, J = 8.1 Hz, 1H,
Ar), 7.29 (t, J = 7.8 Hz, 1H, Ar), 4.70 (s, 5H, C5H5), 0.94 (m, 6H,
P(CH2CH3)3), 0.66 (dt, J = 14.6, 7.3 Hz, 9H, P(CH2CH3)3). 13C NMR
(125 MHz, DMSO-d6): d (ppm) 171.0 (C@O), 170.8 (C@O), 154.1,
153.7, 153.2, 144.1, 130.0, 129.5, 125.3, 123.7, 123.4, 122.3,
NMR (122 MHz, CDCl3): d (ppm) 154.4. IR (film):
2932, 2852, 1742 (C@O), 1685 (C@O), 1581, 1499, 1415, 1338,
m
(cmꢀ1) 2947,
1318, 1281, 1228, 1168, 1124, 1021, 828, 747. HRMS calcd for
C
32H37N3O5PRuSi (M+H)+ 692.1278, found (M+H)+ 692.1289.
4.3.8. Compound 6d
TBS-protected complex 5d (12.5 mg, 0.018 mmol) was taken up
in 2 mL of dry CH2Cl2 and cooled to 0 °C. To this was added a 1.0 M
121.2, 118.9, 116.2, 114.0, 110.7, 72.2 (C5H5), 16.6 (d, JC–P
=
solution of TBAF in THF (19.1 lL, 0.019 mmol) causing the reaction
23 Hz, P(CH2CH3)3), 7.2 (P(CH2CH3)3). IR (film):
m
(cmꢀ1) 3113,
to immediately turn red. After stirring for 15 min at 0 °C, the reac-
tion was quenched by exposing it to acetic acid vapor. The reaction
was then concentrated and subjected to flash chromatography
over silica gel with toluene:acetone 20:1. The product 6d eluted
as a dark purple band that dried to a blue green solid (5.9 mg,
91%) based on recovered starting material. 1H NMR (500 MHz,
CDCl3): d (ppm) 9.07 (m, 2H, Ar), 8.86 (d, J = 7.8 Hz, 1H, Ar), 7.62
(d, J = 8.1 Hz, 1H, Ar), 7.44 (br s, 1H, NH), 7.40 (m, 2H, Ar), 4.83
(s, 5H, C5H5), 3.14 (d, J = 11.3 Hz, 9H, P(OCH3)3). 13C NMR
(90 MHz, CDCl3): d (ppm) 170.2 (C@O), 170.1 (C@O), 155.7, 154.3,
153.8 (d, JC–P = 2.8 Hz), 145.4, 132.1, 131.0, 126.0, 125.2, 124.4,
122.3, 121.8, 119.9, 116.1, 116.0, 111.1, 75.5 (d, JC–P = 3.3 Hz,
C5H5), 51.3 (d, JC–P = 3.0 Hz, P(OCH3)3). 31P NMR (122 MHz, CDCl3):
3042, 2966, 2932, 2727, 1742 (C@O), 1700 (C@O), 1579, 1528,
1492, 1418, 1342, 1286, 1260, 1226, 1182, 1126, 1029, 796, 751,
707. HRMS calcd for C28H28N3O2PRu (M)+ 571.0963, found (M)+
571.0969.
4.3.6. Compound 6c
To an argon saturated solution of CH2Cl2 (3 mL) at 0 °C, was
added ligand 4 (10.0 mg, 0.025 mmol) and precursor complex 1
(10.8 mg, 0.025 mmol) to give a dark solution. After stirring
5 min at 0 °C, (ꢀ)-sparteine was added (6.9
lL, 0.030 mmol) caus-
ing the reaction to become dark purple. After stirring for 45 min at
0 °C, P(CH2OH)3 (9.3 mg, 0.075 mmol) was added and the reaction
was allowed to warm slowly to room temperature. After 1 h, the
green reaction was concentrated and subjected to flash chromatog-
raphy over silica gel with a 35:1 CH2Cl2:MeOH mobile phase
ramped slowly to 15:1 CH2Cl2:MeOH. The product 5c eluted as a
blue purple band that also contained sparteine. This residue was
taken up in 2 mL of dry CH2Cl2. To this solution was added a
d (ppm) 154.1. IR (film):
m
(cmꢀ1) 3207, 3049, 2919, 2854, 1746
(C@O), 1695 (C@O), 1582, 1532, 1491, 1417, 1343, 1287, 1263,
1226, 1152, 1124, 1017, 743. HRMS calcd for C26H23N3O5PRu
(M+H)+ 578.0413, found (M+H)+ 578.0421.
4.3.9. Compound 5e
Free ligand 4 (17.4 mg, 0.0419 mmol) and complex 1 (20.0 mg,
0.0461 mmol) were added together to a dry 10 mL two-necked
round bottomed flask and placed under argon. The flask was cooled
to 0 °C and CH2Cl2 (4 mL) was added turning the reaction dark
1.0 M solution of TBAF in THF (38 lL, 0.038 mmol) causing the
reaction color to immediately lighten. After stirring for 5 min at
room temperature, the reaction was quenched by exposing it to
acetic acid vapor. The reaction was then concentrated and sub-
jected to flash chromatography over silica gel with CH2Cl2:MeOH
20:1. The product 6c eluted as a dark green band that dried to a
green solid (3.2 mg, 22% two steps). 1H NMR (500 MHz, CDCl3): d
(ppm) 9.39 (d, J = 5.1 Hz, 1H, Ar), 9.00 (d, J = 8.4 Hz, 1H, Ar), 8.80
(d, J = 7.6 Hz, 1H, Ar), 8.01 (s, 1H, NH), 7.68 (d, J = 8.2 Hz, 1H, Ar),
7.56–7.51 (m, 2H, Ar), 7.34 (t, J = 7.9 Hz, 1H, Ar), 4.81 (s, 5H,
C5H5), 3.71 (d, J = 13.2 Hz, 3H, P(CH2OH)3), 3.61 (d, J = 13.2 Hz,
maroon. After stirring 5 min at 0 °C, (ꢀ)-sparteine (13.8
lL,
0.060 mmol) was added causing the reaction to become dark pur-
ple. After stirring for 45 min at 0 °C, the reaction was purged with
freshly generated PF3 gas using argon as a carrier gas, while slowly
warming to room temperature. During this time, the reaction be-
came deep red. After 2 h, the reaction was concentrated and sub-
jected to silica gel chromatography with toluene:acetone 50:1.
The product 5e eluted as a bright red band (10.5 mg). Some TBS-
deprotected material (6e) could be eluted as a more polar purple
band (1.0 mg) resulting in an overall yield of 43%. 1H NMR
(360 MHz, CDCl3): d (ppm) 9.26 (dt, J = 8.3, 1.1 Hz, 1H, Ar), 8.88
(m, 2H, Ar), 7.57 (ddd, J = 8.4, 7.0, 1.3 Hz, 1H, Ar), 7.47 (dd, J = 8.3,
5.1 Hz, 1H, Ar), 7.41 (m, 2H, Ar), 5.14 (d, J = 1.3 Hz, 5H, C5H5),
3H, P(CH2OH)3). IR (film):
m
(cmꢀ1) 3410 (br, OH), 3263, 2922,
2852, 1743 (C@O), 1698 (C@O), 1579, 1523, 1493, 1469, 1418,
1343, 1287, 1261, 1227, 1187, 1098, 1076, 1024, 845, 821, 797,
748, 708, 637. HRMS calcd for
C
26H23N3O5PRu (M-CH3)+
562.0106, found (M-CH3)+ 562.0033.

40
C. Streu et al. / Inorganica Chimica Acta 377 (2011) 34–41
1.06 (s, 9H, SiC(CH3)3), 0.62 (s, 6H, Si(CH3)2). 13C NMR (90 MHz,
CDCl3): d (ppm) 175.7 (C@O), 175.1 (C@O), 155.1, 154.4 (d, JC–P
4.3.12. Compound 8
=
To a N2-saturated solution of CH2Cl2/MeCN (2 mL/0.4 mL) were
added ligand 9b (30 mg, 0.048 mmol) and ruthenium complex 1
(25.1 mg, 0.058 mmol) as solids. After stirring for 5 min at 0 °C,
N,N-diisopropylethylamine (10
mixture was allowed to warm to room temperature and stirred
overnight. A 1 M solution of PMe3 in THF (144 L, 0.144 mmol)
3.4 Hz), 153.4, 145.2, 134.5, 133.2, 126.3, 125.5, 124.5, 122.1,
122.1, 120.1, 115.9, 115.2, 114.5, 79.0 (d, JC–P = 4.3 Hz, C5H5), 26.7
(SiC(CH3)3), 19.4 (SiC(CH3)3), -3.7 (Si(CH3)2). 31P NMR (122 MHz,
lL, 0.058 mmol) was added. The
CDCl3): d (ppm) 134 (q, JP–F = 1341 Hz). IR (film):
m
(cmꢀ1) 2926,
2854, 1740 (C@O), 1688 (C@O), 1586, 1504, 1416, 1337, 1262,
l
1229, 1180, 1127, 1046, 849 (P–F), 747, 663, 576. HRMS calcd for
C
was added to the purple solution. After 1 h, the green solution
was concentrated and subjected to flash chromatography over sil-
ica gel with hexanes:EtOAc (first 10:1, then 8:1). The product was
concentrated to a green solid (18.5 mg) that was carried forward
without characterization. To a solution (5.2 mg) in CH2Cl2 (2 mL)
28H28F3N3O2PRuSi (M+H)+ 656.0679, found (M+H)+ 656.0687.
4.3.10. Compound 6e
TBS-protected complex 5e (10.5 mg, 0.016 mmol) was taken up
in dry CH2Cl2 (2 mL) and cooled to 0 °C. To this was added tetrabu-
tylammonium fluoride (1.0 M solution in THF) (17.6 lL,
at 0 °C was added a 1 M solution of TBAF in hexane (18 lL,
0.018 mmol). After stirring for 5 min at 0 °C, the reaction was
quenched with one drop of glacial acetic acid. The solution was
then concentrated and subjected to flash chromatography over sil-
ica gel with CH2Cl2:MeOH (first 100:1, then 50:1). The complex 8
was concentrated to a green solid (2.9 mg, 36% over both steps).
1H NMR (400 MHz, DMSO-d6): d (ppm) 11.04 (s, 1H, NH), 10.47
(d, J = 8.6 Hz, 1H, Ar), 9.96 (d, J = 2.1 Hz, 1H, Ar), 9.05 (s, 1H, OH),
8.28 (d, J = 2.4 Hz, 1H, Ar), 8.23 (d, J = 7.8 Hz, 1H, Ar), 7.95 (t,
J = 8.2 Hz, 1H, Ar), 7.84 (t, J = 7.7 Hz, 1H, Ar), 7.42 (d, J = 8.6 Hz,
1H, Ar), 7.09 (dd, J = 8.6, 2.5 Hz, 1H, Ar), 4.74 (s, 5H, C5H5), 0.74
(d, JH–P = 9.1 Hz, 6H, P(CH3)3). 13C NMR (100.6 MHz, DMSO-d6): d
(ppm) 171.0 (C@O), 170.5 (C@O), 156.6 (d, JC–P = 4.1 Hz), 154.3,
150.8, 147.9, 139.9, 131.1, 130.4, 130.1 (d, JC–P = 0.9 Hz), 128.7,
127.9, 127.7, 127.6 (d, JC–P = 2.1 Hz), 123.5, 119.7, 116.4, 115.9,
0.018 mmol) causing the reaction to immediately turn purple.
After stirring for 3 min at 0 °C, the reaction was quenched by
exposing it to acetic acid vapor. The reaction was then concen-
trated and subjected to silica gel chromatography with tolu-
ene:acetone 10:1. The product 6e eluted as a light purple band
(4.0 mg, 46%). 1H NMR (500 MHz, DMSO-d6): d (ppm) 11.07 (s,
1H, NH), 9.28 (d, J = 5.0 Hz, 1H, Ar), 9.09 (d, J = 8.2 Hz, 1H, Ar),
8.66 (d, J = 7.9 Hz, 1H, Ar), 7.75 (dd, J = 8.4, 5.1 Hz, 1H, Ar), 7.55
(m, 2H, Ar), 7.35 (ddd, J = 8.0, 5.5, 2.5 Hz, 1H, Ar), 5.44 (s, 5H,
C5H5). 13C NMR (125 MHz, CDCl3): d (ppm) 169.9 (C@O), 169.6
(C@O), 155.3, 154.6 (d, JC–P = 2.6 Hz), 153.5, 144.8, 134.2, 131.5,
126.7, 125.4, 124.3, 122.4, 122.3, 120.5, 116.5, 115.3, 112.2, 79.0
(d, JC–P = 3.8 Hz, C5H5). 31P NMR (122 MHz, CDCl3): d (ppm) 134
115.8, 110.9, 109.3, 72.7 (d, JC–P = 2.3 Hz, C5H5), 16.7 (d, JC–P
=
(q, JP–F = 1341 Hz). IR (film):
m
(cmꢀ1) 3192, 2920 , 2854 , 1746
25.7 Hz, P(CH3)3). IR (film):
m
(cmꢀ1) 3419 (br, OH), 3127, 2925,
(C@O), 1700 (C@O), 1581, 1538, 1519, 1494, 1460, 1417, 1343,
2853, 1741 (C@O), 1694 (C@O), 1678, 1581, 1492, 1464, 1335,
947, 756. HRMS calcd for C29H25N3O3PRu (M+H)+ 596.0679, found
(M+H)+ 596.0666.
1291, 1262, 1229, 1151, 1011, 854 (P–F), 741. HRMS calcd for
C
22H14F3N3O2PRu (M+H)+ 541.9814, found (M+H)+ 541.9816.
4.4. X-ray crystallography
4.3.11. Compound 7
To an argon saturated solution of CH2Cl2 (2 mL) was added li-
Single crystals suitable for X-ray diffraction studies were grown
by slow diffusion of pentane into a solution of 3 in chloroform. This
complex, C32H28N3PO2Ru, crystallized in the triclinic space group
gand 9a (10.0 mg, 0.022 mmol) and ruthenium precursor
(10.0 mg, 0.023 mmol) as solids to give a dark solution. After stir-
ring for 5 min at 0 °C, (ꢀ)-sparteine was added (6.6 L,
0.029 mmol) causing the reaction to turn dark purple. After stirring
for 45 min at 0 °C, a 1.0 M solution of PMe3 in THF (66 L,
1
ꢀ
l
P1 with a = 7.9943(7) Å, b = 10.5921(9) Å, c = 16.772(2) Å,
a
= 105.989(3)°, b = 91.311(2)°, c
= 98.649(2)°, V = 1346.7(2) Å3,
l
Z = 2 and dcalc = 1.526 g/cm3. X-ray intensity data were collected
0.066 mmol) was added and the reaction was allowed to warm
slowly to room temperature. After 1 h, the green reaction was con-
centrated and subjected to flash chromatography over silica gel
with a hexanes:EtOAc 10:1. The TBS protected product of this reac-
tion was concentrated to a green solid (4.9 mg) that was carried
forward without characterization. To a solution of the TBS pro-
tected complex (4.9 mg, 0.007 mmol) in CH2Cl2 (2 mL) at 0 °C
on a Rigaku Mercury CCD area detector employing graphite-mono-
chromated Mo K
a radiation (k = 0.71073 Å) at a temperature of
143 K. Preliminary indexing was performed from a series of twelve
0.5° rotation images with exposures of 60 s. A total of 830 rotation
images were collected with a crystal to detector distance of 35 mm,
a 2h swing angle of ꢀ10°, rotation widths of 0.5° and exposures of
30 s: scan no. 1 was a /-scan from 52.5° to 262.5° at
x
= 10° and
= ꢀ90°
-scan from ꢀ20° to 4° at
= ꢀ90° and / = 315°; scan no. 4 was an -scan from ꢀ20° to 8°
= ꢀ90° and / = 225°. Rotation images were processed using
(F2) values
was added a 1.0 M solution of TBAF in THF (19.0
lL, 0.019 mmol)
x
= 20°; scan no. 2 was an
x
-scan from ꢀ20° to 20° at
v
causing the reaction to immediately become red colored. After stir-
ring for 15 min at 0 °C, the reaction was quenched with 1 drop of
HOAc. The reaction was then concentrated and subjected to flash
chromatography over silica gel with toluene:acetone 10:1. The
product 7 concentrated to a green solid (2.4 mg, 59%). 1H NMR
(500 MHz, CDCl3): d (ppm) 10.55 (d, J = 9.0 Hz, 1H, Ar), 9.63 (s,
1H, Ar), 9.03 (d, J = 7.8 Hz, 1H, Ar), 7.96 (t, J = 7.5 Hz, 1H, Ar), 7.79
(t, J = 5.8 Hz, 1H, Ar), 7.61 (t, J = 7.6 Hz, 1H, Ar), 7.53 (m, 2H, Ar),
7.39 (m, 2H, Ar and NH), 4.65 (s, 5H, C5H5), 0.83 (d, J = 8.5 Hz,
9H, P(CH3)3). 13C NMR (125 MHz, DMSO-d6): d (ppm) 171.1
(C@O), 170.5 (C@O), 157.2, 154.6, 153.8, 139.7, 130.8, 130.7,
130.1, 128.8, 128.1, 127.7, 126.4, 125.3, 124.6, 123.1, 119.9,
and / = 135°; scan no. 3 was an
x
v
x
at
v
CrystalClear, producing a listing of unaveraged F2 and
r
which were then passed to the CrystalStructure program package
for further processing and structure solution on a Dell Pentium
III computer. A total of 10950 reflections were measured over the
ranges 5.06 6 2h 6 50.04°, ꢀ9 6 h 6 8, ꢀ12 6 k 6 12, ꢀ19 6 l 6 19
yielding 4716 unique reflections (Rint = 0.0262). The intensity data
were corrected for Lorentz and polarization effects and for absorp-
tion using REQAB (minimum and maximum transmission 0.824,
1.000). The structure was solved by direct methods (SIR97). Refine-
ment was by full-matrix least squares based on F2 using SHELXL-97.
All reflections were used during refinement (F2’s that were exper-
imentally negative were replaced by F2 = 0). The weighting scheme
118.5, 115.9, 115.7, 112.5, 72.8 (d, JC–P = 2.4 Hz, C5H5), 16.7 (d, JC–P
=
25.8 Hz, P(CH3)3). IR (film):
m
(cmꢀ1) 3121, 3056, 2961, 2921,
2850, 2741, 1743 (C@O), 1696 (C@O), 1618, 1579, 1533, 1462,
1423, 1380, 1328, 1293, 1227, 1123, 1022, 814, 758. HRMS calcd
for C29H24N3O2PRu (M)+ 579.0650, found (M)+ 579.0861.
used was w = 1/[
3. Non-hydrogen atoms were refined anisotropically and hydrogen
r
2(F2o ) + 0.0595P2 + 1.5778P] where P = (Fo2 + 2F2c )/

C. Streu et al. / Inorganica Chimica Acta 377 (2011) 34–41
41
(h) C.L. Davies, E.L. Dux, A.-K. Duhme-Klair, Dalton Trans. (2009) 10141;
(i) C.G. Hartinger, P.J. Dyson, Chem. Soc. Rev. (2009) 38, 391;
(j) R.H. Fish, Aust. J. Chem. 63 (2010) 1505;
(k) E.A. Hillard, G. Jaouen, Organometallics 30 (2011) 20;
(l) G. Gasser, I. Ott, N. Metzler-Nolte, J. Med. Chem. 54 (2011) 3.
atoms were refined using a ‘‘riding’’ model. Refinement converged
to R1 = 0.0408 and wR2 = 0.1039 for 4216 reflections for which
F > 4
4716 unique, non-zero reflections and 356 variables. The maxi-
mum in the final cycle of least squares was 0.001 and the
r(F) and R1 = 0.0459, wR2 = 0.1087 and GOF = 1.063 for all
[2] This is for example illustrated by a review of drugs approved by the US
Food and Drug Administration during 2007 in which not single
D/r
a
two most prominent peaks in the final difference Fourier were
+1.409 and ꢀ0.787 eÅ3. Table 1 lists cell information, data collec-
tion parameters, and refinement data.
compound contains a metal atom. See: B. Hughes, Nat. Rev. Drug Discov.
7 (2008) 107.
[3] For a very recent example, see: L. Feng, Y. Geisselbrecht, S. Blanck, A. Wilbuer,
G.E. Atilla-Gokcumen, P. Filippakopoulos, K. Kräling, M.A. Celik, K. Harms, J.
Maksimoska, R. Marmorstein, G. Frenking, S. Knapp, L.-O. Essen, E. Meggers, J.
Am. Chem. Soc. 133 (2011) 5976.
[4] E. Meggers, Curr. Opin. Chem. Biol. 11 (2007) 287.
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Acknowledgements
We would like to thank Prof. Jeffrey D. Winkler (Department of
Chemistry, University of Pennsylvania) for generously providing
equipment and facilities as well as his helpful discussions on the
topic. We would also like to thank Dr. Nicholas Pagano for assis-
tance with the TrkA assay.
Appendix A. Supplementary material
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45.
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Supplementary data associated with this article can be found, in
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