Electronic effects of substituents on the stability of the iridanaphthalene compound [IrCp{C(OMe)CHC(o-C6H4)(Ph)}(PMe3)]PF6

Article abstract of DOI:10.1039/c4dt02744b

Iridanaphthalene complexes are synthesized from the corresponding methoxy(alkenyl)carbeneiridium compounds. The electronic character of the substituents on the 6-position of the metallanaphthalene ring is crucial from the point of view of the stability of the iridanaphthalene, [IrCp{C(OMe)CHC(o-C₆H₄)(Ph)}(PMe₃)]PF₆, vs. its transformation to the corresponding indanone derivatives. Stability studies of the iridanaphthalene compounds revealed that strong electron donor substituents (-OMe) stabilize the iridanaphthalene, while weak electron donor (-Me) and electron withdrawing (-NO₂) groups favor the formation of indanone derivatives. Two possible indanone isomers can be obtained in the conversion of the unstable iridanaphthalene complexes and a mechanism for the formation of these isomers is proposed. This journal is

Full text of DOI:10.1039/c4dt02744b

Dalton
Transactions
PAPER
Electronic effects of substituents on the
stability of the iridanaphthalene compound
[IrCp*{vC(OMe)CHvC(o-C6H4)(Ph)}(PMe3)]PF6†
Cite this: Dalton Trans., 2014, 43,
17366
M. Talavera,a J. Bravo,a J. Castro,a S. García-Fontán,a J. M. Hermida-Ramónb and
S. Bolaño*a
Iridanaphthalene complexes are synthesized from the corresponding methoxy(alkenyl)carbeneiridium
compounds. The electronic character of the substituents on the 6-position of the metallanaphthalene ring is
crucial from the point of view of the stability of the iridanaphthalene, [IrCp*{vC(OMe)CHvC(o-C6H4)-
(Ph)}(PMe3)]PF6, vs. its transformation to the corresponding indanone derivatives. Stability studies of
the iridanaphthalene compounds revealed that strong electron donor substituents (–OMe) stabilize the
iridanaphthalene, while weak electron donor (–Me) and electron withdrawing (–NO2) groups favor the
formation of indanone derivatives. Two possible indanone isomers can be obtained in the conversion
of the unstable iridanaphthalene complexes and a mechanism for the formation of these isomers is
proposed.
Received 9th September 2014,
Accepted 4th October 2014
DOI: 10.1039/c4dt02744b
www.rsc.org/dalton
We reported iridanaphthalene [IrCp*{vC(OMe)CHvC(o-C6H4)-
(Ph)}(PMe3)]PF6, which is unstable in solution and evolves into
Introduction
Transition-metal cyclometalated complexes have increased 3-phenyl-1-indanone.3c In order to exploit the full potential of
their presence in organometallic chemistry. Much of the iridanaphthalene complexes it is important to understand
growing interest stems from a plethora of applications, for substituent effects on the metallanaphthalene ring. Herein,
example, in organic transformations, catalysis, material we report the synthesis of a series of new methoxy(alkenyl)-
science, and medicinal chemistry.1 Within the large family of carbeneiridium compounds bearing substituents of different
metallacycle compounds, the metallaaromatics have especially electronic behavior and the corresponding iridanaphthalene
attracted attention since they can display both aromatic pro- complexes. In addition, we study how the substituents influ-
perties and organometallic reactivity.2 The metal center, co- ence the conversion of the iridanaphthalene complexes to the
ligands, and substituents on the ring play an important role in corresponding indanone derivatives.
the stabilization of these metallacycle compounds. Xia et al.
have reported how phosphonium substituents on the aromatic
ring are able to stabilize a great variety of osmaaromatic com- Results and discussion
plexes.1b Understanding how substituents on the ring with
different electronic properties affect the stability of these
derivatives is crucial to optimize their synthesis, reactivity
and applications. Metallanaphthalenes or superior analogs
Synthesis and characterization
The methoxy(alkenyl)carbeneiridium complexes 1–3 were pre-
pared by a reaction of [IrCp*Cl(NCMe)(PMe3)]PF6 with the
corresponding propargylic alcohol I–III (Scheme 1). The pro-
ducts 1–3 which contain a –NO2, –OMe or –Me substituent,
are practically unknown and very few examples have been
isolated,3 making their exploration of great interest in order to
respectively, on one of the phenyl rings of the (alkenyl)carbene
gain access to a promising rich chemistry.
ligand were isolated as a mixture of cis/trans isomers with
respect to the Cβ–Cγ double bond.
aDepartamento de Química Inorgánica, Universidad de Vigo, Campus Universitario,
E-36310 Vigo, Spain. E-mail: bgs@uvigo.es
The corresponding mixture of two iridanaphthalene
isomers 4(A,B)–6(A,B) were obtained using our synthetic
route:3c by treatment of 1–3 with AgPF6 at room temperature,
implying an intramolecular C–H bond activation of one phenyl
ring of the (alkenyl)carbene ligand. It is a good general strategy
for the preparation of a family of iridanaphthalene complexes
bDepartamento de Química Física, Universidad de Vigo, Campus Universitario,
E-36310 Vigo, Spain
†Electronic supplementary information (ESI) available: Crystal structure deter-
mination of 4B. CCDC 1010426. For ESI and crystallographic data in CIF or
other electronic format see DOI: 10.1039/c4dt02744b
17366 | Dalton Trans., 2014, 43, 17366–17374
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Dalton Transactions
Paper
Scheme 1 Synthesis of methoxy(alkenyl)carbeneiridium complexes 1–3 and their conversion to the respective iridanaphthalene compounds 4–6.
from different aryl substituents of the (alkenyl)carbene ligand. sphere is completed by a phosphane ligand (PMe3) with a
Isomer A has a substituent on the 6-position of the irida- “three-legged piano stool” structure in an octahedral arrange-
naphthalene skeleton, and the B isomer has a substituent on ment. The iridanaphthalene shows Ir–C bond lengths of 1.965(4)
the para-position of the phenyl ring (Scheme 1).
and 2.037(4) Å. The distance between the iridium atom and
Multidimensional and multinuclear NMR spectra, summar- the plane defined by the five carbon atoms of the ring is 0.425(5)
ized in the Experimental section, supported the proposed Å, showing an envelope distortion. These data are similar to
structure for all complexes and, in particular, the NOESY previously reported iridanaphthalene complexes.3,4
spectra confirm the cis/trans isomerism.
When the mixture of 4(A,B) was treated with
a
How do the substituents influence the stability of the
iridanaphthalene [IrCp*{vC(OMe)CHvC(o-C6H4)(Ph)}-
(PMe3)]PF6?
solution of NaBPh4 in methanol, brown monocrystals of
[IrCp*{vC(OMe)CHvC(o-C6H4)(p-NO2-C6H4)(PMe3)]BPh4 (4B)
were obtained. The structure of 4B was confirmed by single-
crystal X-ray diffraction analysis and the ORTEP representation
of the complex cation 4B accompanied by a selection of dis-
tances and angles is given in Fig. 1. The asymmetric unit of
complex 4B contains an iridium cation complex, a BPh4– anion
and a CH2Cl2 solvent molecule.
We studied the influence of the electronic character of the substitu-
ent on the 6-position of the naphthalene ring on the stability of the
iridanaphthalene complex [IrCp*{vC(OMe)CHvC(o-C6H4)-
(Ph)}(PMe3)]PF6, that is, the degree of conversion of the
iridanaphthalene complex to the corresponding indanone
derivatives, choosing –OMe, –Me, and –NO2 as substituents
due to their different electronic effects.
The cation consists of
a pentamethylcyclopentadienyl
ligand (Cp*) η5-coordinated to an iridium atom. The metal
The nature of all the indanone derivatives5 (Chart 1) was
confirmed by multidimensional and multinuclear NMR spec-
troscopy (Experimental section).
becomes part of the naphthalene moiety and the coordination
When a solution of the nitroiridanaphthalene isomeric
mixture 4(A,B) (∼57 : 43 mole ratio) in 1,2-dichloroethane was
heated at 338 K for 24 hours, 7b was isolated in a 90% yield
and 4A was recovered unaltered. In an attempt to obtain the
indanone derivative 7a corresponding to 4A, a solution of 4A
in 1,2-dichloroethane was heated at 368 K for 24 hours, result-
ing in a mixture of nitro-indanone derivatives 7a and 7b in a
∼30 : 70 mole ratio (estimated by NMR, 91% yield of the iso-
lated mixture), respectively. This suggests that:
Fig. 1 ORTEP view of the cation [IrCp*{vC(OMe)CHvC(o-C6H4)-
(p-NO2-C6H4)(PMe3)]+ (4B) drawn at a 50% probability level. Hydrogen
atoms are not shown. Selected bond lengths (Å) and angles (deg): Ir–CT,
1.9167(3); Ir–C(11), 1.965(4); Ir–C(15), 2.037(4); Ir–P(1), 2.2754(11); C(11)–
Ir–C(15), 89.47(16); CT–Ir–C(11), 125.49(11); CT–Ir–C(15), 123.26(12);
C(15)–Ir–P(1), 89.46(12); C(11)–Ir–P(1), 87.43(12). CT refers to the centroid
of the Cp* ligand.
Chart 1 Indanone derivatives.
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(1) nitro-iridanaphthalene isomer 4A is more stable than 4B proportion (80% regarding initial quantity). To confirm that 8a
and requires harsher reaction conditions to convert it into the is formed only from 5A and 8b only from 5B, a solution of 5A
indanone derivatives.
in 1,2-dichloroethane was heated at 368 K for 24 hours. 8a
(2) nitro-iridanaphthalene isomer 4A evolves into the nitro- together with 6-methoxy-3-phenylinden-1-one (∼70 : 30 mole
indanone derivatives 7a and 7b, with 7b being the major ratio estimated by NMR, respectively) were obtained and 5A
product. This seems to indicate that during the conversion of was recovered at 78% regarding initial quantity. The formation
4A in the corresponding indanone derivative 7a, a transform- of 8b was not observed. This suggests that the conversion of
ation occurs giving 7b as the major product (path “b” in iridanaphthalene 5A to the respective methoxy-indanone
Scheme 2). It has been tested that 7a does not evolve to 7b derivative is less favored than that of 4A into the corres-
under the same conditions.
ponding nitro-indanone derivatives 7(a,b). In this example, the
The nitro group is an electron-withdrawing group through methoxy group is an electron-withdrawing group and reson-
resonance and induction, and thus the ortho- and para-posi- ance donor but in alkoxy groups the resonance overrides
tions to the nitro group have a positive partial charge. We induction. This means that ortho- and para-positions to the
propose that the reaction follows a mechanism (Scheme 2) methoxy group have a negative partial charge. Thus, formation
where the nitro group stabilizes the carbanion C and favors of carbanion C is not favored and path “b” is not followed.
path “b” over path “a”.6
This significantly increases the stability of iridanaphthalene
Path “a”: involves a carbene migratory insertion, leading to 5A with respect to the formation of the methoxy-indanone
a η1-indenyl intermediate followed by switching from η1 to η3 derivatives and it is only converted in 14% yield through path
hapticity to give the η3-indenyl complex, which detaches from “a” (Scheme 2).
the metallic center to form an indanone derivative.3c
The mixture of methyl-iridanaphthalene isomers 6(A,B)
Path “b”: involves the initial formation of carbanion C, fol- (∼50 : 50 mole ratio) in 1,2-dichloroethane at 338 K for 24 hours
lowed by a rotation over the Cγ–C1 σ bond and abstraction of a gave the methyl-indanone derivatives, 9a and 9b, with a
proton. Subsequent electronic rearrangements and rotations ∼45 : 55 mole ratio (estimated by NMR) in a 91% yield of the
give an iridanaphthalene complex with the substituent in the isolated mixture. In this case, isomer 6A evolved to 9a and 6B to
para-position of the phenyl ring. This finally evolves into the 9b. Because the methyl group is a weak electron donor with no
corresponding indanone derivative.7
resonance effect, the carbanion is not favored and the stability
When a mixture of 5(A,B) (∼33 : 66 mole ratio) in 1,2- of the iridanaphthalene decreases in favor of the methyl-inda-
dichloroethane was heated at 338 K for 24 hours, methoxy- none derivative formation following path “a” (Scheme 2).
indanone derivatives 8a and 8b were obtained in
a
Our results from solution stability studies of the irida-
∼13 : 87 mole ratio (estimated by NMR) (50% yield of the iso- naphthalene compounds presented in this work demonstrate
lated mixture), respectively, and 5A was recovered in a minor that donor substituents (–OMe) on the 6-position of the
Scheme 2 Proposed mechanism for the formation of the indanone derivatives from the iridanaphthalene complex substituted on 6-position of the
naphthalene ring.
17368 | Dalton Trans., 2014, 43, 17366–17374
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Dalton Transactions
Paper
naphthalene skeleton stabilize the iridanaphthalene over the most abundant isotopes and they were acquired using an
indanone derivative formation, whereas weak electron-donor Apex-Qe spectrometer by high resolution electrospray
(–Me) and electron-withdrawing (–NO2) substituents on the technique for the organometallic complexes and a high and low
a
6-position favor the formation of indanone derivatives.
resolution electron impact technique for the organic compounds.
X-ray diffraction analysis
Conclusion
Crystallographic data were collected on a Bruker Smart 1000
CCD diffractometer at CACTI (Universidade de Vigo) using
graphite-monochromated Mo Kα radiation (λ = 0.71073 Å), and
were corrected for Lorentz and polarisation effects. The soft-
ware SMART10 was used for collecting frames of data, indexing
reflections, and the determination of lattice parameters,
SAINT11 for the integration of the intensity of reflections and
scaling, and SADABS12 for empirical absorption correction.
The crystallographic treatment of the compound was per-
formed with the Oscail program.13 The structure was solved by
direct methods and refined by a full-matrix least-squares based
on F2.14 All non-hydrogen atoms were refined with anisotropic
displacement parameters. Hydrogen atoms were included in
idealized positions and refined with isotropic displacement
parameters.
In conclusion, we presented the synthesis of new cis- and
trans-isomers of methoxy(alkenyl)carbeneiridium complexes
containing a nitro, methoxy or methyl substituent on one of
the phenyl rings of the (alkenyl)carbene ligand. A mixture of
two iridanaphthalene isomers was obtained from the
methoxy(alkenyl)carbeneiridium complexes, one with the
substituent on the 6-position of the iridanaphthalene skel-
eton and the other one with the substituent on the para-posi-
tion of the phenyl ring. Given the broad range of properties,
reactivity, and applications related to metallaaromatic com-
pounds and that the metallanaphthalene compounds are
practically unknown,3 it is important to understand how the
substituents on the naphthalene skeleton affect their stabi-
lity. Our studies indicate that the substituents have a signi-
ficant effect on the stability of the iridanaphthalene complex
[IrCp*{vC(OMe)CHvC(o-C6H4)(Ph)}(PMe3)]PF6 in the conver-
sion to their corresponding indanone derivatives, with a
π-donor substituent on the 6-position of the naphthalene
skeleton stabilizing the iridanaphthalene. This information
will be important for further exploration of different ways
to create stable iridanaphthalene compounds to study their
properties and future applications in material science.
Crystal data and structural refinement details for complex
4B are given in Table 1.
Preparation of cis- and trans-[IrCp*Cl{vC(OMe)–CHv
C(p-NO2–C6H4)(Ph)}(PMe3)]PF6 (1). To a yellow solution of
[IrCp*Cl(NCMe)(PMe3)]PF6 (300 mg, 0.48 mmol) in methanol
(20 mL) 1-(4-nitrophenyl)-1-phenyl-2-propyn-1-ol (159 mg,
Table 1 Crystal data and structure refinement for 4B
Empirical formula
Formula wt
Temp (K)
Wavelength (Å)
Cryst. syst.
C54H58BCl2NO3PIr
1073.89
100(2)
0.71073
Experimental section
Synthetic procedures, materials and methods
Monoclinic
All experiments were carried out under an atmosphere of Space group
P21/n
18.696(2)
11.6073(14)
24.032(3)
a (Å)
argon by Schlenk techniques. Solvents were dried by the usual
b (Å)
c (Å)
procedures8 and, prior to use, distilled under argon. The start-
3c
ing material [IrCp*Cl(NCMe)(PMe3)]PF6
was prepared as α (°)
90
β (°)
112.526(2)
90
4817.2(10)
4
1.481
2.960
2176
0.29 × 0.24 × 0.19
2.36–28.09
described in the literature. All reagents were obtained from
commercial sources except for the propargylic alcohols (I,II,
III), which were synthesized following the method described
by Mantovani et al.9 Unless stated, NMR spectra were recorded
at room temperature on a Bruker ARX-400 instrument, with
γ (°)
V (Å3)
Z
Density (Mg m−3
)
Abs. coeff. (mm−1
F(000)
)
resonating frequencies of 400 MHz (1H), 161 MHz (31P{1H}), Cryst. size (mm)
and 100 MHz (13C{1H}) using the solvent as the internal lock.
1H and 13C{1H} signals are referred to internal TMS and those
of 31P{1H} to 85% H3PO4; downfield shifts (expressed in ppm)
are considered positive. 1H and 13C{1H} NMR (or JMOD) signal
assignments were confirmed by {1H, 1H} COSY, {1H, 1H}
θ range for data collection (°)
Index ranges
–24 ≤ h ≤ 24
–15 ≤ k ≤ 15
–31 ≤ l ≤ 31
No. of rflns collected
No. of indep. rflns
No. of rflns obsd (>2σ)
82 883
11 700 [R(int) = 0.0593]
9026
0.997
Semi-empirical from equivalents
0.4309 and 0.3395
Full-matrix least-squares on F2
11 700/0/577
NOESY, {1H,13C} HSQC, {1H,13C} HMBC and DEPT experi- Data completeness
ments. Coupling constants are given in hertz. The isomer
Abs. cor.
Max. and min. transmission
Refinement method
ratios were determined using relaxation delays as long as 30 s
in order to collect reliable integral data of the 1H NMR resonances. No. of data/restraints/params
Goodness of fit on F2
R indices [I > 2σ(I)]
1.084
Infrared spectra were run on a Jasco FT/IR-6100 spectrometer
using KBr pellets. C, H, and N analyses were carried out with a
R1 = 0.0347, wR2 = 0.0668
R1 = 0.0599, wR2 = 0.0784
5.259 and −3.510
R indices (all data)
Carlo Erba 1108 analyzer. Mass spectra are referred to the Largest diff. peak and hole (e Å–3
)
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0.62 mmol) was added and the mixture was stirred for 20 min. 4JHP = 2.2 Hz, C5(CH3)5); 3.85 (s, 3H, C4–OCH3); 4.05 (s, 3H,
3
The dark red solution obtained was concentrated under Cα–OCH3); 6.93 (d, 2H, JHH = 9.1 Hz, C3H); 7.09–7.12 (m, 2H,
3
vacuum yielding a dark red solid that was washed with Ph); 7.37 (d, 2H, JHH = 9.1 Hz, C2H); 7.43–7.47 (m, 3H, Ph);
1
pentane (3 × 5 mL) and diethylether (2 × 5 mL). Finally, it was 7.49 (s br, 1H, CβH) ppm. 31P{1H} NMR: δ −144.17 (sept, JPF
=
dried under a vacuum giving a mixture of cis-, trans-1 isomers 710.5 Hz, PF6); −31.05 (s, P(CH3)3) ppm. 13C{1H} NMR: δ 9.2
1
in a ∼50 : 50 mole ratio (estimated by NMR), respectively. Yield (s, C5(CH3)5); 15.0 (d, JCP = 40.5 Hz, P(CH3)3); 56.1 (s,
2
(isolated mixture): 400 mg (98%).
C4–OCH3); 68.0 (s, Cα–OCH3); 98.6 (d, JCP = 2.6 Hz, C5(CH3)5);
Anal. calcd for C29H37O3NClF6IrP2 (851.23
g
mol−1): 115.1 (s, 2C C3); 128.7 (s, 2C Ph); 128.7 (s, 2C Ph); 129.4
C 40.92, H 4.38, N 1.65; found: C 41.05, H 4.45, N 1.71. MS (s, 1C Ph); 132.1 (s, C1); 132.3 (s, 2C C2); 136.7 (d, 3JCP = 3.1 Hz,
(m/z): 706.18114 [M]+. IR (cm−1): ν (NO2) 1519 (m), 1346 (m); Cβ); 139.7 (s, Cipso); 163.5 (s, C4); 155.6 (s br, Cγ); 259.4 (d,
(PF6) 840 (s). cis-1: 1H NMR: δ 1.69 (d, 9H, JHP = 11.0 Hz, 2JCP = 11.5 Hz, Cα) ppm.
2
4
P(CH3)3); 1.79 (d, 15H, JHP = 2.2 Hz, C5(CH3)5); 4.20 (s, 3H,
Preparation of cis- and trans-[IrCp*Cl{vC(OMe)–CHv
OCH3); 7.34 (d, 2H, JHH = 8.9 Hz, C2H); 7.37–7.39 (m, 2H, Ph); C(p-CH3–C6H4)(Ph)}(PMe3)]PF6 (3). To a yellow solution of
3
3
7.40–7.60 (m, 3H, Ph); 7.64 (s br, 1H, CβH); 8.30 (d, 2H, JHH
=
=
[IrCp*Cl(NCMe)(PMe3)]PF6 (150 mg, 0.24 mmol) in methanol
(10 mL), 1-(4-methylphenyl)-1-phenyl-2-propyn-1-ol (70 mg,
8.9 Hz, C3H) ppm. 31P{1H} NMR: δ −144.14 (sept, JPF
1
710.9 Hz, PF6); −30.93 (s, P(CH3)3) ppm. 13C{1H} NMR: δ 9.2 0.31 mmol) was added and the mixture was stirred for 15 min.
1
(s, C5(CH3)5); 15.2 (d, JCP = 40.9 Hz, P(CH3)3); 68.9 (s, OCH3); The dark solution obtained was vacuum-concentrated yielding
99.2 (d, JCP = 2.2 Hz, C5(CH3)5); 124.0 (s, 2C C3); 129.2 a dark green solid that was washed with pentane (2 × 5 mL)
2
(s, 2C C2); 129.7 (s, 2C Ph); 129.8 (s, 2C Ph); 132.3 (s, 1C Ph); and diethylether (2 × 5 mL). Finally, it was dried under a
138.9 (s, Cipso); 139.5 (s, Cβ); 146.1 (s, C1); 148.2 (s, C4); 150.7 vacuum giving
a mixture of cis-, trans-3 isomers in a
(s br, Cγ); 264.0 (s br, Cα) ppm. trans-1: H NMR: δ 1.70 (d, 9H, ∼50 : 50 mole ratio (estimated by NMR), respectively. Yield
1
2JHP = 11.0 Hz, P(CH3)3); 1.74 (d, 15H, JHP = 2.1 Hz, C5(CH3)5); (isolated mixture): 153 mg (78%).
4.17 (s, 3H, OCH3); 6.97 (s br, 1H, CβH); 7.12–7.15 (m, 2H, Ph);
4
Anal. calcd for C30H40OClF6IrP2 (820.26 g mol−1): C 43.93,
7.40–7.60 (m, 3H, Ph); 7.59 (d, 2H, JHH = 8.9 Hz, C2H); 8.22 H 4.92; found: C 44.06, H 4.96. MS (m/z): 675.21166 [M]+. IR
3
(d, 2H, JHH = 8.9 Hz, C3H) ppm. 31P{1H} NMR: δ −144.14 (cm−1): ν (PF6) 839 (s). cis-3: 1H NMR: δ 1.70 (d, 9H, JHP
=
3
2
(sept, JPF = 710.9 Hz, PF6); −29.41 (s, P(CH3)3) ppm. 13C{1H} 11.0 Hz, P(CH3)3); 1.77 (d, 15H, JHP = 2.2 Hz, C5(CH3)5); 2.42
1
4
1
3
NMR: δ 9.2 (s, C5(CH3)5); 15.2 (d, JCP = 40.9 Hz, P(CH3)3); 69.0 (s, 3H, CH3); 4.10 (s, 3H, OCH3); 7.01 (d, 2H, JHH = 8.1 Hz,
(s, OCH3); 100.2 (s br, C5(CH3)5); 124.3 (s, 2C C3); 130.6 C3H); 7.13 (s br, 1H, CβH); 7.18–7.33 (m, 2H, C2H); 7.36–7.55
(s, 2C C2); 129.4 (s, 2C Ph); 129.7 (s, 2C Ph); 129.8 (s, 1C Ph); (m, 5H, Ph) ppm. 31P{1H} NMR: δ −144.17 (sept, JPF
=
1
137.9 (s, Cipso); 139.8 (s, Cβ); 146.8 (s, C1); 149.0 (s, C4); 150.7 710.6 Hz, PF6); −29.80 (s, P(CH3)3) ppm. 13C{1H} NMR: δ 9.3
1
(s br, Cγ); 264.0 (s br, Cα) ppm.
(s, C5(CH3)5); 15.1 (d, JCP = 40.4 Hz, P(CH3)3); 21.5 (s, CH3);
Preparation of cis- and trans-[IrCp*Cl{vC(OMe)–CHv 68.5 (s, OCH3); 99.4 (d, JCP = 2.17 Hz, C5(CH3)5); 128.7–130.3
2
C(p-OCH3–C6H4)(Ph)}(PMe3)]PF6 (2). To a yellow solution of (all s, 5C Ph + 4C C6H4CH3); 137.9 (s br, Cβ); 139.5 (s, Cipso);
2
[IrCp*Cl(NCMe)(PMe3)]PF6 (150 mg, 0.24 mmol) in methanol 140.7 (s, C1); 140.8 (s, C4); 154.3 (s br, Cγ); 261.6 (d, JCP
=
=
2
(10 mL), 1-(4-methoxyphenyl)-1-phenyl-2-propyn-1-ol (74 mg, 11.1 Hz, Cα) ppm. trans-3: 1H NMR: δ 1.70 (d, 9H, JHP
4
0.31 mmol) was added and the mixture was stirred for 15 min. 10.9 Hz, P(CH3)3); 1.78 (d, 15H, JHP = 2.3 Hz, C5(CH3)5); 2.37
The dark solution obtained was vacuum-concentrated yielding (s, 3H, CH3); 4.08 (s, 3H, OCH3); 7.08–7.12 (m, 2H, Ph);
a dark red solid that was washed with pentane (2 × 5 mL) and 7.18–7.33 (m, 4H, C3H + C2H); 7.36–7.55 (m, 4H, CβH + Ph)
1
diethylether (2 × 5 mL). Finally, it was dried under a vacuum ppm. 31P{1H} NMR: δ −144.17 (sept, JPF = 710.6 Hz, PF6);
giving cis-, trans-2 isomers in a ∼33 : 66 mole ratio (estimated −30.56 (s, P(CH3)3) ppm. 13C{1H} NMR: δ 9.2 (s, C5(CH3)5); 15.0
by NMR), respectively. Yield (isolated mixture): 150 mg (75%).
(d, 1JCP = 40.6 Hz, P(CH3)3); 21.7 (s, CH3); 68.3 (s, OCH3); 98.9 (d,
Anal. calcd for C30H40O2ClF6IrP2 (836.26 g mol−1): C 43.09, 2JCP = 2.3 Hz, C5(CH3)5); 128.7–130.3 (all s, 5C Ph + 4C C6H4CH3);
H 4.82; found: C 43.36, H 4.77. MS (m/z): 691.20651 [M]+; 136.2 (s, C1); 137.3 (s, Cipso); 137.7 (d, JCP = 2.3 Hz, Cβ); 143.2
3
655.22979 [M − HCl]+. IR (cm−1): ν (PF6) 840 (s). cis-2: (s, C4); 154.7 (s br, Cγ); 261.2 (d, 2JCP = 10.3 Hz, Cα) ppm.
2
1H NMR: δ 1.70 (d, 9H, JHP = 11.0 Hz, P(CH3)3); 1.77 (d, 15H,
The synthesis of complexes 1–3 was done with different
4JHP = 2.3 Hz, C5(CH3)5); 3.87 (s, 3H, C4–OCH3); 4.11 (s, 3H, experimental conditions trying to direct the synthesis towards
3
Cα–OCH3); 6.94 (d, 2H, JHH = 9.0 Hz, C3H); 7.01 (s br, 1H, one isomer but a mixture of cis/trans isomers was always
3
CβH); 7.09 (d, 2H, JHH = 9.0 Hz, C2H); 7.37–7.40 (m, 2H, Ph); obtained. Different attempts to separate them by a silica
7.40–7.43 (m, 3H, Ph) ppm. 31P{1H} NMR: δ −144.17 (sept, column were unsuccessful. Using this mixture did not have
1JPF = 710.5 Hz, PF6); −29.59 (s, P(CH3)3) ppm. 13C{1H} NMR: any influence on the cyclometallation reaction since each
1
δ 9.3 (s, C5(CH3)5); 15.0 (d, JCP = 40.5 Hz, P(CH3)3); 55.9 (s, isomer gives the corresponding isomer of iridanaphthalene as
2
C4–OCH3); 68.4 (s, Cα–OCH3); 99.4 (d, JCP = 2.2 Hz, C5(CH3)5); it is observed in the isomers ratio.
114.4 (s, 2C C3); 129.5 (s, 3C Ph); 130.2 (s, 2C Ph); 131.2 (s, C1);
Preparation of [IrCp*{vC(OMe)–CHvC(o-C6H3–p-NO2)-
131.7 (s, 2C C2); 137.4 (s br, Cβ); 141.1 (s, Cipso); 161.9 (s, C4); (Ph)}(PMe3)]PF6 (4A) and [IrCp*{vC(OMe)–CHvC(o-C6H4)-
2
154.1 (s br, Cγ); 260.6 (d, JCP = 11.9 Hz, Cα) ppm. trans-2: (p-NO2–C6H4)}(PMe3)]PF6 (4B). A dark red solution of the
2
1H NMR: δ 1.70 (d, 9H, JHP = 10.8 Hz, P(CH3)3); 1.78 (d, 15H, mixture cis-, trans-1 (∼50 : 50 mole ratio, 350 mg, 0.41 mmol) in
17370 | Dalton Trans., 2014, 43, 17366–17374
This journal is © The Royal Society of Chemistry 2014

Dalton Transactions
Paper
2
30 mL of dichloromethane was treated with AgPF6 (117 mg, 1H NMR: δ 1.31 (d, 9H, JHP = 9.8 Hz, P(CH3)3); 1.45 (d, 15H,
3
0.45 mmol). The brown solution was stirred for 5 min at room 4JHP = 2.0 Hz, C5(CH3)5); 3.86 (s, 3H, OCH3); 5.98 (d, 1H, JHP
=
3
temperature, and then filtered obtaining a brown oil that was 10.6 Hz, C2H); 6.57 (d, 1H, JHH = 7.6 Hz, C6H4); 6.84 (d, 1H,
treated with pentane obtaining a brown solid that was washed 3JHH = 7.6 Hz, C6H4); 7.41–7.46 (m, 3H, C6H4 + C2′H + C6′H);
with pentane (3 × 5 mL). Finally, the solid was dried under a 7.79–7.84 (m, 1H, C6H4); 8.17–8.22 (m, 2H, C3′H + C5′H) ppm.
1
vacuum obtaining a mixture of isomers 4(A,B) (∼57 : 43 mole ratio 31P{1H} NMR: δ −144.16 (sept, JPF = 710.6 Hz, PF6); −38.92
estimated by NMR, respectively). Yield (mixture isolated): 240 mg (s, P(CH3)3)ppm. 13C{1H} NMR: δ 8.9 (s, C5(CH3)5); 18.2 (d,
2
(72%). This solid was dissolved in dichloromethane and a solu- 1JCP = 38.5 Hz, P(CH3)3); 62.0 (s, OCH3); 96.4 (d, JCP = 2.6 Hz,
tion of NaBPh4 in methanol was added dropwise yielding brown C5(CH3)5); 187.0 (C1, observed by {1H, 13C} HMBC correlations)
monocrystals of complex 4B adequate for X-ray diffraction analysis. ppm.
Anal. calcd for C29H36O3NF6IrP2 (814.77 g mol−1): C 42.75, H
Preparation of [IrCp*{vC(OMe)–CHvC(o-C6H3–p-OCH3)-
4.45, N 1.72; found: C 42.88, H 4.48, N 1.76. MS (m/z): 670.20487 (Ph)}(PMe3)]PF6 (5A) and [IrCp*{vC(OMe)–CHvC(o-C6H4)-
[M]+. IR (cm−1): ν (NO2) 1519 (m) and 1345 (m); (PF6) 839 (s).
(p-OCH3–C6H4)}(PMe3)]PF6 (5B). A dark red solution of the
4A: 1H NMR: δ 1.30 (d, 9H, 2JHP = 10.9 Hz, P(CH3)3); 1.84 (d, mixture cis-, trans-2 (∼33 : 66 mole ratio, 150 mg, 0.18 mmol)
4
5
15H, JHP = 1.7 Hz, C5(CH3)5); 4.50 (d, 3H, JHP = 0.8 Hz, in 10 mL of dichloromethane was treated with AgPF6 (50 mg,
OCH3); 6.80 (d, 1H, JHP = 1.0 Hz, C2H); 7.42–7.47 (m, 2H, Ph); 0.20 mmol). The brown solution was stirred for 5 min at room
4
7.56–7.60 (m, 3H, Ph); 7.79–7.83 (m, 1H, C4H); 7.85–7.90 (m, temperature, and then filtered and vacuum-concentrated
1H,C5H); 8.63 (d, 1H, JHP = 2.4 Hz, C7H) ppm. 31P{1H} NMR: giving a dark green oil that was treated with pentane obtaining
4
δ −144.14 (sept, 1JPF = 711.3 Hz, PF6); −34.43 (s, P(CH3)3) ppm. a dark green solid that was washed with pentane (3 × 5 mL).
13C{1H} NMR: δ 9.6 (s, C5(CH3)5); 14.2 (d, JCP = 41.1 Hz, Finally, the solid was dried under a vacuum obtaining a
1
2
P(CH3)3); 64.9 (s, OCH3); 100.9 (d, JCP = 1.8 Hz, C5(CH3)5); mixture of isomers 5(A,B) (∼33 : 66 mole ratio estimated by
118.0 (s, C5); 121.8 (d, 3JCP = 1.9 Hz, C2); 129.0 (s, 1C Ph); 129.1 NMR, respectively). Yield (isolated mixture): 110 mg (76%).
(s, 2C Ph); 129.3 (s, 2C Ph); 136.2 (d, JCP = 4.7 Hz, C7); 137.2
Anal. calcd for C30H39O2F6IrP2 (799.80 g mol−1): C 45.05,
3
(s, C4); 140.6 (s, C9); 140.9 (s, Cipso); 146.8 (s, C6); 154.2 (d, H 4.91; found: C 45.23, H 4.96. MS (m/z): 655.23038 [M]+.
2JCP = 10.3 Hz, C8); 175.1 (s, C3); 251.2 (d, JCP = 9.7 Hz, C1) IR (cm−1): ν (PF6) 839 (s).
2
ppm. 4B: 1H NMR: δ 1.27 (d, 9H, JHP = 11.0 Hz, P(CH3)3); 1.81
5A: 1H NMR: δ 1.27 (d, 9H, JHP = 10.8 Hz, P(CH3)3); 1.80
2
2
(d, 15H, JHP = 1.7 Hz, C5(CH3)5); 4.43 (d, 3H, JHP = 0.7 Hz, (d, 15H, JHP = 1.6 Hz, C5(CH3)5); 3.91 (s, 3H, C6–OCH3); 4.31
4
5
4
OCH3); 6.59 (d, 1H, JHP = 1.0 Hz, C2H); 7.14–7.17 (m, 2H, (s, 3H, C1–OCH3); 6.54 (s, 1H, C2H); 6.74 (dd, 1H, JHH
=
4
3
C4H + C5H); 7.48–7.51 (m, 1H, C6H); 7.61–7.64 (m, 2H, C2′H + 9.2 Hz, JHH = 2.7 Hz, C5H); 7.37–7.40 (m, 3H, Ph + C7H);
4
C6′H); 7.87–7.88 (m, 1H, C7H); 8.33–8.37 (m, 2H, C3′H + C5′H) 7.50–7.54 (m, 3H, Ph); 7.62 (d, 1H, JHH = 8.9 Hz, C4H) ppm.
3
ppm. 31P{1H} NMR: δ −144.14 (sept, JPF = 710.7 Hz, PF6); 31P{1H} NMR: δ −144.17 (sept, JPF = 710.4 Hz, PF6); −34.99
1
1
−34.80 (s, P(CH3)3) ppm. 13C{1H} NMR: δ 9.7 (s, C5(CH3)5); 14.1 (s, P(CH3)3) ppm. 13C{1H} NMR: δ 9.7 (s, C5(CH3)5); 14.1 (d,
1
2
(d, JCP = 41.0 Hz, P(CH3)3); 64.1 (s, OCH3); 100.5 (d, JCP
=
1JCP = 40.9 Hz, P(CH3)3); 55.8 (s, C6–OCH3); 63.0 (s, C1–OCH3);
1.9 Hz, C5(CH3)5); 118.5 (d, 3JCP = 2.1 Hz, C2); 123.8 (s, C5); 124.0 100.0 (d, JCP = 2.0 Hz, C5(CH3)5); 110.4 (s, C5); 116.1 (d, JCP
=
2
3
(s, C3′ + C5′); 130.6 (s, C2′ + C6′); 132.1 (s, C4); 133.1 (s, C9); 137.2 2.0 Hz, C2); 126.9 (s, Cipso); 127.9 (d, JCP = 5.2 Hz, C7);
3
(s, C6); 143.2 (d, JCP = 4.7 Hz, C7); 148.1 (s, C4′ + C1′); 156.5 (d, 128.8–129.7 (all s, Ph); 140.5 (s, C4); 142.4 (s, C9); 160.1 (d,
3
2JCP = 10.3 Hz, C8); 175.1 (s, C3); 249.5 (d, 2JCP = 9.9 Hz, C1) ppm. 2JCP = 10.1 Hz, C8); 162.0 (s, C6); 178.7 (s, C3); 241.7 (d, JCP
=
2
Note: During NMR characterization the formation of 7b was 10.6 Hz, C1) ppm. 5B: H NMR: δ 1.24 (d, 9H, JHP = 10.8 Hz,
1
2
4
observed.
P(CH3)3); 1.77 (d, 15H, JHP = 1.6 Hz, C5(CH3)5); 3.90 (s, 3H,
Preparation of [IrCp*{η3-(C9H5)(OMe)(p-NO2–C6H4)}(PMe3)]- C6–OCH3); 4.38 (s, 3H, C1–OCH3); 6.64 (s, 1H, C2H); 7.05 (d,
PF6 (D). In a NMR tube, a mixture of 4(A,B) (57 : 43 mole ratio, 2H, JHH = 8.8 Hz, C3′H + C5′H); 7.09–7.14 (m, 1H, C6H);
3
10 mg, 0.012 mmol) was dissolved in 500 μL of dichloro- 7.14–7.19 (m, 1H, C5H); 7.41 (d, 2H, JHH = 7.13 Hz, C2′H +
3
methane-d2 and heated at 308 K for 7 days. After that, complex C6′H); 7.71 (dd, 1H, JHH = 7.8 Hz, JHH = 1.7 Hz, C4H);
3
4
4A remained unaltered and 4B had almost completely evolved 7.80–7.84 (m, 1H, C7H) ppm. 31P{1H} NMR: δ −144.17 (sept,
to a new complex [IrCp*{η3-(C9H5)(OMe)-(p-NO2–C6H4)}(PMe3)]- 1JPF = 710.4 Hz, PF6); −34.83 (s, P(CH3)3) ppm. 13C{1H} NMR:
1
PF6 (∼10 : 90 mole ratio estimated by NMR, respectively).
δ 9.7 (s, C5(CH3)5); 14.3 (d, JCP = 40.8 Hz, P(CH3)3); 56.0 (s,
2
C6–OCH3); 63.6 (s, C1–OCH3); 99.8 (d, JCP = 2.0 Hz, C5(CH3)5);
3
114.4 (s, C3′ + C5′); 118.7 (d, JCP = 2.0 Hz, C2); 123.6 (s, C5);
131.2 (s, C2′ + C6′); 131.6 (s, C6); 134.2 (s, C1′); 134.5 (s, C9);
137.7 (s, C4); 143.1 (d, 3JCP = 5.1 Hz, C7); 156.0 (d, 2JCP = 9.9 Hz,
C8); 161.8 (s, C4′); 178.9 (s, C3); 246.7 (d, 2JCP = 10.4 Hz, C1) ppm.
Preparation of [IrCp*{vC(OMe)–CHvC(o-C6H3–p-CH3)-
(Ph)}(PMe3)]PF6 (6A) and [IrCp*{vC(OMe)–CHvC(o-C6H4)-
(p-CH3–C6H4)}(PMe3)]PF6 (6B). A green solution of the
mixture cis-, trans-3 (∼50 : 50 mole ratio, 130 mg, 0.16 mmol)
in 10 mL of dichloromethane was treated with AgPF6 (45 mg,
This journal is © The Royal Society of Chemistry 2014
Dalton Trans., 2014, 43, 17366–17374 | 17371

Paper
Dalton Transactions
0.17 mmol). The brown solution was stirred for 5 min at room δ 44.5 (s, C3); 46.7 (s, C2); 123.9 (s, C7); 124.5 (s, C3′ + C5′); 127.2
temperature, and then filtered and vacuum-concentrated (s, C4); 128.8 (s, C6); 129.0 (s, C2′ + C6′); 135.7 (s, C5); 137.3
giving a dark green oil that was treated with pentane obtaining (s, C8); 147.4 (s, C4′); 151.8 (s, C1′); 156.7 (s, C9); 204.6 (s, CO) ppm.
a dark green solid that was washed with pentane (3 × 5 mL).
A dark brown solution of the complex 4A previously isolated
The solid obtained was dried under a vacuum yielding a (60.4 mg, 0.074 mmol) in 10 mL of 1,2-dichloroethane was
mixture of the isomers 6(A,B) (∼50 : 50 mole ratio estimated by stirred and heated at 368 K for 24 hours. The brown solution
NMR, respectively). Yield (isolated mixture): 105 mg (84%).
obtained was vacuum-concentrated yielding a brown oil. The
Anal. calcd for C30H39OF6IrP2 (783.80 g mol−1): C 45.97, H mixture of 7(a,b) (∼30 : 70 mole ratio estimated by NMR,
5.02; found: C 45.19, H 5.07. MS (m/z): 639.22447 [M]+. IR respectively) was extracted with diethylether and purified
(cm−1): ν (PF6) 840 (s).
through a silica column using hexane–AcOEt (7 : 4) as the
2
6A: 1H NMR: δ 1.25 (d, 9H, JHP = 10.9 Hz, P(CH3)3); 1.78 eluent. Yield (isolated mixture): 17 mg (91%) (∼27% for 7a,
(d, 15H, 4JHP = 1.6 Hz, C5(CH3)5); 2.41 (s, 3H, CH3); 4.35 (s, 3H, ∼64% for 7b). 7a: 1H NMR: δ 2.81 (dd, 1H, JHH = 19.5 Hz,
2
OCH3); 6.58 (s, 1H, C2H); 6.94–7.00 (m, 1H, C5H); 7.39–7.42 3JHH = 4.1 Hz, C2H2); 3.35 (dd, 1H, JHH = 19.4 Hz, JHH
=
2
3
(m, 2H, Ph); 7.51–7.56 (m, 4H, H4 + Ph); 7.66–7.68 (m, 1H, 8.2 Hz, C2H2); 4.69 (dd, 1H, JHH = 8.3 Hz, 3JHH = 4.0 Hz, C3H);
3
C7H) ppm. 31P{1H} NMR: δ −144.17 (sept, 1JPF = 710.4 Hz, PF6); 7.12–7.38 (Ph, overlapped with isomer 7b); 7.45 (d, 1H, JHH
=
3
−34.87 (s, P(CH3)3) ppm. 13C{1H} NMR: δ 9.7 (s, C5(CH3)5); 14.2 8.4 Hz, C4H); 8.40 (dd, 1H, JHH = 8.4 Hz, JHH = 2.2 Hz, C5H);
3
4
1
4
(d, JCP = 40.7 Hz, P(CH3)3); 21.3 (s, CH3); 63.4 (s, OCH3); 99.9 8.56 (d, 1H, JHH = 2.1 Hz, C7H) ppm. 13C{1H} NMR: δ 45.0
2
3
(d, JCP = 1.8 Hz, C5(CH3)5); 117.7 (d, JCP = 2.0 Hz, C2); 124.8 (s, C3); 47.5 (s, C2); 119.0 (s, C7); 126.7–130.4 (Ph + C4, over-
(s, C5); 128.6–129.9 (all s, Ph); 131.4 (s, C9); 137.8 (s, C4); 142.1 lapped with isomer 7b); 129.5 (s, C5); 138.1 (s, C8); 142.6
(s, Cipso); 142.9 (s, C6); 143.9 (d, JCP = 4.9 Hz, C7); 157.0 (d, (s, C6); 136.4 (s, C1′); 163.8 (s, C9); 203.8 (s, CO) ppm.
3
2JCP = 10.2 Hz, C8); 179.3 (s, C3); 245.7 (d, JCP = 10.3 Hz, C1)
Preparation of 6-methoxy-3-phenylindan-1-one (8a) and
2
ppm. 6B: 1H NMR: δ 1.25 (d, 9H, JHP = 10.9 Hz, P(CH3)3); 1.78 3-(4-methoxyphenyl)indan-1-one (8b). A dark brown solution
(d, 15H, 4JHP = 1.6 Hz, C5(CH3)5); 2.47 (s, 3H, CH3); 4.37 (s, 3H, of a 5(A,B) mixture (∼33 : 66 mole ratio, 100 mg, 0.125 mmol)
OCH3); 6.63 (s, 1H, C2H); 7.10–7.14 (m, 2H, C5H + C6H); in 10 mL of 1,2-dichloroethane was stirred and heated at 338 K
2
7.32–7.35 (m, 4H, C6H4CH3); 7.66–7.70 (m, 1H, C4H); 7.81–7.84 for 24 hours. The brown solution obtained was vacuum-con-
(m, 1H, C7H) ppm. 31P{1H} NMR: δ −144.17 (sept, JPF
=
centrated yielding a brown oil from which 8(a,b) were extracted
1
710.4 Hz, PF6); −35.05 (s, P(CH3)3) ppm. 13C{1H} NMR: δ 9.7 with diethylether. The solid that remained after the extraction
1
(s, C5(CH3)5); 14.1 (d, JCP = 40.8 Hz, P(CH3)3); 21.5 (s, CH3); was washed with pentane (3 × 4 mL) and it was identified as
2
63.6 (s, OCH3); 100.0 (d, JCP = 1.9 Hz, C5(CH3)5); 118.7 (d, the complex 5A (80% recovered regarding the initial quantity,
3JCP = 2.1 Hz, C2); 123.6 (s, C5); 128.6–129.9 (all s, C6H4CH3); 26.4 mg, 0.033 mmol). The mixture 8(a,b) (∼13 : 87 mole ratio
131.7 (s, C6); 134.4 (s, C9); 137.9 (s, C4); 139.1 (s, C1′); 140.7 estimated by NMR, respectively) was purified through a silica
(s, C4′); 143.0 (d, 3JCP = 5.0 Hz, C7); 156.1 (d, 2JCP = 10.1 Hz, C8); column using hexane–AcOEt (7 : 4) as the eluent. Yield (iso-
179.0 (s, C3); 247.6 (d, 2JCP = 10.4 Hz, C1) ppm.
lated mixture): 15 mg (50%) (∼19% for 8a calculated on
Note: During NMR characterization the formation of 9b complex 5A, ∼65% for 8b calculated on complex 5B). Anal.
(∼5%) was observed.
calcd for C16H14O2 (238.29 g mol−1): C 80.65, H 5.92; found:
Preparation of 6-nitro-3-phenylindan-1-one (7a) and 3-(4- C 80.92, H 6.01. MS (m/z): 239.1024 [M + 1]+; 238.0992 [M];
nitrophenyl)indan-1-one (7b). A dark brown solution of a 4(A,B) 223.08 [M − CH3]+. IR (cm−1): ν (CO) 1710 (s). 8b: 1H NMR:
mixture (∼57 : 43 mole ratio, 106 mg, 0.13 mmol) in 10 mL of δ 2.60 (dd, 1H, JHH = 19.1 Hz, JHH = 3.9 Hz, C2H2); 3.18 (dd,
2
3
1,2-dichloroethane was stirred and heated at 338 K for 1H, JHH = 19.2 Hz, JHH = 8.0 Hz, C2H2); 3.77 (s, 3H, OCH3);
2
3
24 hours. The brown solution obtained was vacuum-concen- 4.55 (dd, 1H, JHH = 7.9 Hz, JHH = 3.9 Hz, C3H); 6.84 (d, 2H,
3
3
trated yielding a brown oil from which the indanone 7b was 3JHH = 8.7 Hz, C3′H + C5′H); 7.05 (d, 2H, JHH = 8.7 Hz, C2′H +
3
extracted with diethylether. The solid that remained after the C6′H); 7.26 (d, 1H, 3JHH = 7.7 Hz, C4H); 7.41 (t, 1H, 3JHH = 7.4 Hz,
extraction was washed with pentane (3 × 4 mL) and it was C6H); 7.55–7.61 (m, 1H, C5H); 7.75 (d, 1H, JHH = 7.6 Hz, C7H)
3
identified as the complex 4A without alteration (60.4 mg, ppm. 13C{1H} NMR: δ 44.0 (s, C3); 47.3 (s, C2); 55.6 (s, OCH3);
0.074 mmol). The indanone 7b was purified through a silica 114.5 (s, C3′ + C5′); 123.4 (s, C7); 127.2 (s, C4); 128.1 (s, C6);
column using hexane–AcOEt (7 : 4) as the eluent. 7b: yield (cal- 129.0 (s, C2′ + C6′); 135.3 (s, C5); 136.3 (s, C1′); 137.1 (s, C8);
culated on the complex 4B): 12.8 mg (90%). Anal. calcd for 158.7 (s, C9); 159.0 (s, C4′); 206.0 (s, CO) ppm.
C15H11O3N (253.26 g mol−1): C 71.14, H 4.38, N 5.53; found:
A dark brown solution of the complex 5A previously isolated
C 71.21, H 4.40, N 5.57. MS (m/z): 254.0769 [M + 1]+; 253.0736 (26.4 mg, 0.033 mmol) in 10 mL of 1,2-dichloroethane was
[M]; 207.08 [M − NO2]+. IR (cm−1): ν (CO) 1712 (s); (NO2) stirred and heated at 368 K for 24 hours. The brown solution
1
2
1518 (s) and 1348 (s). H NMR: δ 2.64 (dd, 1H, JHH = 19.2 Hz, obtained was vacuum-concentrated yielding a brown oil. A
3JHH = 3.9 Hz, C2H2); 3.26 (dd, 1H, JHH = 19.2 Hz, JHH = 8.2 mixture of 8a and 6-methoxy-3-phenylinden-1-one (∼70 : 30 mole
2
3
Hz, C2H2); 4.74 (dd, 1H, JHH = 8.2 Hz, JHH = 3.7 Hz, C3H); ratio, respectively) was extracted with diethylether and purified
7.24–7.28 (m, 1H, C4H); 7.30–7.34 (m, 2H, C2′H + C6′H); through a silica column using hexane–AcOEt (7 : 4) as the
7.45–7.51 (m, 1H, C6H); 7.60–7.65 (m, 1H, C5H); 7.79–7.83 eluent. Yield (isolated mixture): 1.6 mg (∼14% for 8a). The
(m, 1H, C7H); 8.14–8.19 (m, 2H, C3′H + C5′H) ppm. 13C{1H} NMR: solid that remained after the extraction was washed with
3
3
17372 | Dalton Trans., 2014, 43, 17366–17374
This journal is © The Royal Society of Chemistry 2014

Dalton Transactions
Paper
pentane (3 × 4 mL) and it was identified as the complex 5A
Chem. Res., 2014, 47, 341–354 and references within;
(c) J. Chen and G. Jia, Coord. Chem. Rev., 2013, 257, 2491–
2521; (d) J. Campos, M. F. Espada, J. López-Serrano and
E. Carmona, Inorg. Chem., 2013, 52, 6694–6704 and refer-
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5 Indanone derivatives 8(a,b) and 9(a,b): (a) B. V. Ramulu,
A. G. K. Reddy and G. Satyanarayana, Synlett, 2013, 868–
872; (b) R. Rendy, Y. Zhang, A. McElrea, A. Gomez and
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(78% recovered regarding the initial quantity, 16.4 mg,
2
0.033 mmol). 8a: 1H NMR: δ 2.64 (dd, 1H, JHH = 19.2 Hz,
2
3
3JHH = 3.6 Hz, C2H2); 3.22 (dd, 1H, JHH = 19.1 Hz, JHH = 7.9
Hz, C2H2); 3.86 (s, 3H, OCH3); 4.53 (dd, 1H, JHH = 7.8 Hz,
3
3JHH = 3.7 Hz, C3H); 7.10–7.14 (m, 2H, Ph); 7.15–7.17 (m, 2H,
C4H + C5H); 7.20–7.25 (m, 2H, C7H + Ph); 7.28–7.33 (m, 2H, Ph)
ppm. 13C{1H} NMR: δ 44.1 (s, C3); 47.9 (s, C2); 56.1 (s, OCH3);
104.8 (s, C7); 124.4 (s, C5); 127.2 (s, 2C Ph); 127.8 (s, 1C Ph);
127.9 (s, 2C Ph); 128.0 (s, C4); 160.2 (C6, observed by {1H, 13C}
HMBC correlations) ppm. Due to the final product mixture,
the rest of the signals could not be assigned.
Preparation of 6-methyl-3-phenylindan-1-one (9a) and
3-(4-methylphenyl)indan-1-one (9b). A dark green suspension
of 6(A,B) (∼50 : 50 mole ratio, 80 mg, 0.10 mmol) in 10 mL of
1,2-dichloroethane was stirred and heated at 338 K for 24 hours.
The brown solution obtained was filtered and vacuum-concen-
trated giving a brown oil. The mixture of 9(a,b) (∼45 : 55 mole
ratio, respectively) was purified through a silica column using
hexane–AcOEt (95 : 5) as the eluent. Yield (isolated mixture):
20.2 mg (91%) (∼41% for 9a calculated on complex 6A, ∼50%
for 9b calculated on complex 6B).
Anal. calcd for C16H14O (222.29 g mol−1): C 86.45, H 6.35;
found: C 86.62, H 6.39. MS (m/z): 223.1079 [M + 1]+; 222.1040
[M]; 207.08 [M − CH3]+; 145.06 [M − Ph]+; 130.04 [M − C6H4
1
− CH3]+. IR (cm−1): ν (CO) 1713 (s). 9a: H NMR: δ 2.42 (s, 3H,
2
3
CH3); 2.64 (dd, 1H, JHH = 19.1 Hz, JHH = 3.6 Hz, C2H2); 3.20
(dd, 1H, JHH = 19.1 Hz, JHH = 8.0 Hz, C2H2); 4.55 (dd, 1H,
2
3
3JHH = 7.8 Hz, JHH = 3.9 Hz, C3H); 7.13–7.18 (m, 4H, C4H +
3
Ph); 7.28–7.33 (m, 2H, Ph); 7.39–7.44 (m, 1H, C5H); 7.55–7.60
(m, 1H, C7H) ppm. 13C{1H} NMR: δ 21.2 (s, CH3); 44.4 (s, C3);
47.5 (s, C2); 123.3 (s, C7); 126.8 (s, C4); 127.2 (s, 1C Ph); 128.0
(s, 2C Ph); 129.2 (s, 2C Ph); 135.6 (s, C5); 137.1 (s, C8); 138.4
(s, C6); 144.6 (s, C1′); 155.8 (s, C9); 205.9 (s, CO) ppm. 9b:
2
1H NMR: δ 2.32 (s, 3H, CH3); 2.63 (dd, 1H, JHH = 19.1 Hz,
2
3
3JHH = 3.8 Hz, C2H2); 3.18 (dd, 1H, JHH = 19.1 Hz, JHH
=
8.0 Hz, C2H2); 4.56 (dd, 1H, JHH = 7.8 Hz, 3JHH = 3.9 Hz, C3H);
3
7.02 (d, 2H, JHH = 8.1 Hz, C2′H + C6′H); 7.13 (d, 2H, JHH
=
3
3
7.7 Hz, C3′H + C5′H); 7.22–7.29 (m, 1H, C4H); 7.39–7.44 (m, 1H,
C6H); 7.55–7.60 (m, 1H, C5H); 7.76 (d, 1H, JHH = 7.7 Hz, C7H)
3
ppm. 13C{1H} NMR: δ 21.1 (s, CH3); 44.4 (s, C3); 47.1 (s, C2);
123.4 (s, C7); 127.1 (s, C4); 127.8 (s, C2′ + C6′); 128.0 (s, C6);
129.8 (s, C3′ + C5′); 135.3 (s, C5); 137.0 (s, C4′); 137.1 (s, C8);
141.3 (s, C1′); 158.6 (s, C9); 206.0 (s, CO) ppm.
6 In the proposed mechanism, path “a” is known (ref. 2c and
references within); path “b” is proposed to explain the for-
mation of the indanone derivatives where the substituent
resides on the phenyl substituent.
7 In order to obtain more information about this reaction, a
solution of the mixture 4(A,B) (∼57 : 43 mole ratio) was
prepared in CD2Cl2. After six days at 308 K. 4A remained
unaltered and 4B had almost completely evolved to the
intermediate [IrCp*{η3-(C9H5)(OMe)(p-NO2–C6H4)}(PMe3)]-
PF6 (D) (∼10 : 90 mole ratio estimated by NMR, respectively)
in accordance with our results in a previous work.3c
Acknowledgements
We thank the University of Vigo CACTI services for recording
the NMR spectra. M. T. thank the University of Vigo for
funding through a Predoctoral Fellowship.
Notes and references
8 D. D. Perrin and W. L. F. Armarego, Purification of Labora-
tory Chemicals, Butterworth/Heinemann, London/Oxford,
3rd edn, 1988.
1 (a) M. Albrecht, Chem. Rev., 2010, 110, 576–623 and refer-
ences within; (b) X.-Y. Cao, Q. Zhao, Z. Lin and H. Xia, Acc.
This journal is © The Royal Society of Chemistry 2014
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17374 | Dalton Trans., 2014, 43, 17366–17374
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