C-H bond activation and subsequent C(sp2)-C(sp3) bond formation: Coupling of bromomethyl and triphenylphosphine in an iridium complex

Article abstract of DOI:10.1021/om100187t

Treatment of HC≡CCH(OH)CH=CH₂ with [IrHCl(CO)(PPh ₃)₃]BF₄ at room temperature afforded an iridacyclohexadiene, [Ir(CH=C(PPh₃)CH=CHCH₂)Cl(CO) (PPh₃)₂]BF₄ (1). The reactivity of complex 1 had been investigated. Reaction of 1 with 1 equiv of bromine produced an iridacyclopentadiene, [Ir(CH=C(PPh₃)CH=C(CH₂Br))Cl(CO) (PPh₃)₂]BF₄ (2). When excess bromine was used, iridacyclopentadiene 2 underwent subsequent intramolecular C(sp ²)-C(sp³) coupling between the exocyclic-CH₂Br group and a phenyl of the PPh₃ ligand, leading to the formation of a fused iridacycle complex, [Ir(CH=C(PPh₃)C(Br)=C(CHBr))(P(C ₆H₄)Ph₂)Cl(CO)PPh₃]Br₃ (3). A mechanism for the formation of complex 3 starting from 1 was proposed, in which the process involved a triple C-H activation as well as a rare C(sp ²)-C(sp³) reductive elimination.

Full text of DOI:10.1021/om100187t

2904 Organometallics 2010, 29, 2904–2910
DOI: 10.1021/om100187t
C-H Bond Activation and Subsequent C(sp2)-C(sp3) Bond Formation:
Coupling of Bromomethyl and Triphenylphosphine in an Iridium Complex
Yumei Lin, Hui Xu, Lei Gong, Ting Bin Wen, Xu-Min He,* and Haiping Xia*
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical
Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
Received March 9, 2010
Treatment of HCtCCH(OH)CHdCH2 with [IrHCl(CO)(PPh3)3]BF4 at room temperature afforded
an iridacyclohexadiene, [Ir(CHdC(PPh3)CHdCHCH2)Cl(CO)(PPh3)2]BF4 (1). The reactivity of com-
plex 1 had been investigated. Reaction of 1 with 1 equiv of bromine produced an iridacyclopentadiene,
[Ir(CHdC(PPh3)CHdC(CH2Br))Cl(CO)(PPh3)2]BF4 (2). When excess bromine was used, iridacyclo-
pentadiene 2 underwent subsequent intramolecular C(sp2)-C(sp3) coupling between the exocyclic
-CH2Br group and a phenyl of the PPh3 ligand, leading to the formation of a fused iridacycle complex,
[Ir(CHdC(PPh3)C(Br)dC(CHBr))(P(C6H4)Ph2)Cl(CO)PPh3]Br3 (3). A mechanism for the
formation of complex 3 starting from 1 was proposed, in which the process involved a triple C-H
activation as well as a rare C(sp2)-C(sp3) reductive elimination.
Introduction
transition-metal center, which is expected to be the critical
bond-forming step in coupling reactions, since the me-
tal-carbon bond in a third-row transition-metal complex
is believed to be thermodynamically more stable than that in
a first- or second-row transition-metal complex.5,6 Thus, for
example, for third-row transition-metal complexes, iridium-
mediated catalytic and even stoichiometric C-C bond-form-
ing reactions are much less common than the related chem-
istry of nickel, palladium, and rhodium.6-9 However,
iridium complexes have been used as valuable models for
understanding the mechanisms of catalytic reactions.4,10
Therefore, iridium-catalyzed and iridium-mediated stoichio-
metric C-C bond formation became attractive subjects and
have made impressive progress in recent years.11
The formation of carbon-carbon bonds is at the heart of
the synthesis of organic compounds. Activation of a C-H
bond and subsequent C-C bond formation mediated by
transition-metal complexes are extremely significant topics
and have attracted increasing attention recently.1,2 Among
various strategies to C-H bond activation and C-C bond-
forming, chelation assistance utilizing cyclometalation is
considered to be one of the most promising ways.3
First- and second-row transition-metal complexes of
group VIII have been widely used as catalysts for the C-
C bond formation involving cyclometalation. However,
progress with third-row transition-metal complexes as
catalysts lags far behind.4 This is probably due to the
difficulty of C-C reductive elimination from a third-row
(5) Takeuchi, R. Synlett 2002, 1954.
(6) Li, X.; Appelhans, L. N.; Faller, J. W.; Crabtree, R. H. Organo-
*To whom correspondence should be addressed. (X.-M.H.) Fax:
(þ86)592-218-6628. E-mail: hejin@xmu.edu.cn. (H.P.X.) Fax:
(þ86)592-218-6628. E-mail: hpxia@xmu.edu.cn.
metallics 2004, 23, 3378, and references therein.
(7) See for examples of Ni-catalyzed C-C formation: (a) Phapale,
ꢀ
V. B.; Cardenas, D. J. Chem. Soc. Rev. 2009, 38, 1598. (b) Phapale, V. B.;
ꢀ
~
ꢀ
(1) For recent reviews, see: (a) Trost, B. M.; Toste, F. D.; Pinkerton,
A. B. Chem. Rev. 2001, 101, 2067. (b) Davies, H. M. L.; Beckwith, R. E. J.
Chem. Rev. 2003, 103, 2861. (c) Li, C.-J. Acc. Chem. Res. 2009, 42, 335. (d)
Guisan-Ceinos, M.; Bunuel, E.; Cardenas, D. J. Chem.;Eur. J. 2009, 15,
12681. (c) Son, S.; Fu, G. C. J. Am. Chem. Soc. 2008, 130, 2756.
(8) See for examples of Pd-catalyzed C-C formation: (a) Yin, L.;
Liebscher, J. Chem. Rev. 2007, 107, 133. (b) Beccalli, E. M.; Broggini, G.;
Martinelli, M.; Sottocornola, S. Chem. Rev. 2007, 107, 5318. (c) Aizawa, S.;
Majumder, A.; Yokoyama, Y.; Tamai, M.; Maeda, D.; Kitamura, A. Orga-
nometallics 2009, 28, 6067. (d) Shu, W.; Jia, G.; Ma, S. Org. Lett. 2009, 11,
117. (e) Ariafard, A.; Lin, Z. J. Am. Chem. Soc. 2006, 128, 13010.
(9) See for examples of Rh-catalyzed C-C formation: (a) Colby,
D. A.; Bergman, R. G.; Ellman, J. A. Chem. Rev. 2010, 110, 624. (b)
Lewis, J. C.; Bergman, R. G.; Ellman, J. A. Acc. Chem. Res. 2008, 41, 1013.
(c) Hawkes, K. J.; Cavell, K. J.; Yates, B. F. Organometallics 2008, 27, 4758.
(10) Atwood, J. D. Coord. Chem. Rev. 1988, 83, 93.
ꢀ
Cardenas, D. J. Angew. Chem., Int. Ed. 2003, 42, 384. (e) Trost, B. M.;
Frederiksen, M. U.; Rudd, M. T. Angew. Chem., Int. Ed. 2005, 44, 6630. (f)
ꢀ
Esteruelas, M. A.; Lopez, A. M. Organometallics 2005, 24, 3584.
(2) See for recent examples: (a) Vadola, P. A.; Sames, D. J. Am.
Chem. Soc. 2009, 131, 16525. (b) Flegeau, E. F.; Schneider, U.; Kobayashi,
ꢀ
S. Chem.;Eur. J. 2009, 15, 12247. (c) Esteruelas, M. A.; Hernandez, Y. A.;
ꢀ
ꢀ
~
Lopez, A. M.; Olivan, M.; Onate, E. Organometallics 2007, 26, 2193. (d)
ꢀ
ꢀ
~
Esteruelas, M. A.; Fernandez-Alvarez, F. J.; Olivan, M.; Onate, E. J. Am.
Chem. Soc. 2006, 128, 4596. (e) Bleeke, J. R.; Thananatthanachon, T.; Rath,
N. P. Organometallics 2007, 26, 3904. (f) Bai, T.; Xue, P.; Zhang, L.; Ma, S.;
Jia, G. Chem. Commun. 2008, 2929.
(11) (a) Chin, C. S.; Won, G.; Chong, D.; Kim, M.; Lee, H. Acc.
Chem. Res. 2002, 35, 218. (b) Itoh, J.; Han, S. B.; Krische, M. J. Angew.
Chem., Int. Ed. 2009, 48, 6313. (c) Barchuk, A.; Ngai, M.-Y.; Krische, M. J.
J. Am. Chem. Soc. 2007, 129, 8432. (d) Paneque, M.; Posadas, C. M.;
(3) (a) Ritleng, V.; Sirlin, C.; Pfeffer, M. Chem. Rev. 2002, 102, 1731.
(b) Park, Y. J.; Park, J.-W.; Jun, C.-H. Acc. Chem. Res. 2008, 41, 222. (c) Jun,
C.-H.; Moon, C.-W.; Lee, D.-Y. Chem.;Eur. J. 2002, 8, 2423. (d) Eguillor,
ꢀ
~
ꢀ
Poveda, M. L.; Rendon, N.; Mereiter, K. Organometallics 2007, 26, 3120. (e)
B.; Esteruelas, M. A.; Olivan, M.; Onate, E. Organometallics 2005, 24, 1428.
(e) Zhang, L.; Dang, L.; Wen, T. B.; Sung, H. H.-Y.; Willams, I. D.; Lin, Z.;
Jia, G. Organometallics 2007, 26, 2849. (f) Bleeke, J. R.; Putprasert, P.;
Thananatthanachon, T. Organometallics 2008, 27, 5744.
ꢀ
Jimenez, M. V.; Sola, E.; Lahoz, F. J.; Oro, L. A. Organometallics 2005, 24,
2722. (f) Navarro, J.; Sola, E.; Martín, M.; Dobrionvitch, I. T.; Lahoz, F. J.;
Oro, L. A. Organometallics 2004, 23, 1908. (g) Chin, C. S.; Lee, H.; Noh, S.;
Park, H.; Kim, M. Organometallics 2003, 22, 2119.
(4) Takeuchi, R.; Kezuka, S. Synthesis 2006, 20, 3349.
r
pubs.acs.org/Organometallics
Published on Web 06/04/2010
2010 American Chemical Society

Article
Organometallics, Vol. 29, No. 13, 2010 2905
Scheme 1. Preparation of Iridacyclohexadiene 1
In our recent work, we have developed a convenient route
to prepare some interesting third-row transition-metal-
containing metallacycles,12-15 including metallabenzenes,12
ring-fused metallabenzenoids,13 metallafurans,12c,14 and
bridged metallacycles15 starting from the reactions between
transition-metal-containing complexes and alkynes. As an
outgrowth of our longstanding interest in such reactions, we
16
have studied the reaction of HCtCCH(OH)CHdCH2
with [IrH(CO)Cl(PPh3)3]BF4.17 The reaction led to the for-
mation of an iridacyclohexadiene, [Ir(CHdC(PPh3)CHd
CHCH2)Cl(CO)(PPh3)2]BF4 (1). During our investigation
of the reactivity of 1, we found that it is reactive toward
bromine to produce first iridacyclopentadiene 2, which can
undergo intramolecular C(sp2)-C(sp3) coupling promoted
by the iridium center in the presence of excess bromine to give
the fused iridacycle complex 3. Triple C-H activation
utilizing cyclometalation and C-C reductive elimination is
proposed as the key step for the formation of complex 3
starting from 1 in the mechanism.
Figure 1. Molecular structure of complex 1 (50% probability
thermal ellipsoids). Counteranion and the solvent molecules as
well as some of the hydrogen atoms are omitted for clarity.
˚
Selected bond distances [A] and angles [deg]: Ir(1)-C(1) =
2.061(4), Ir(1)-C(5) =2.131(4), C(1)-C(2) =1.335(6), C(2)-
C(3)=1.473(6), C(3)-C(4)=1.330(6), C(4)-C(5)=1.501(7),
O(1)-C(6) = 1.112(6), Ir(1)-C(6) = 1.938(5), Ir(1)-P(2) =
2.377(1), Ir(1)-P(1) = 2.381(1), C(1)-Ir(1)-C(5) = 91.2(2),
C(2)-C(1)-Ir(1)=129.0(3), C(1)-C(2)-C(3)=125.2(4), C(4)-
C(3)-C(2) = 124.6(4), C(3)-C(4)-C(5) = 130.6(4), C(4)-
C(5)-Ir(1)=118.5(3), P(2)-Ir(1)-P(1)=176.5(1), C(5)-Ir(1)-
Cl(1)=177.7(1), Cl(1)-Ir(1)-C(6)=98.9(1).
Results and Discussion
˚
are 1.473(6) and 1.501(7) A, respectively, consistent with the
Preparation of Iridacyclohexadiene [Ir(CHdC(PPh3)-
CHdCHCH2)Cl(CO)(PPh3)2]BF4 (1). Treatment of [IrHCl-
(CO)(PPh3)3]BF4 with HCtCCH(OH)CHdCH2 in THF at
room temperature led to the precipitation of a white solid
with poor solubility, which could be isolated in 56% yield
and was identified to be an iridacyclohexadiene, [Ir(CHdC-
(PPh3)CHdCHCH2)Cl(CO)(PPh3)2]BF4 (1) (Scheme 1).
The structure of 1 established by X-ray diffraction is
shown in Figure 1. It confirms that complex 1 contains an
almost planar six-membered ring, as reflected by the devia-
value of C-C single bonds.18 The Ir(1)-C(1) (2.061(4) A)
and Ir(1)-C(5) (2.131(4) A) bonds compare well with those
of reported iridacyclohexadiene Ir(CHdC(Me)CHdC(Me)-
˚
˚
˚
CH2)(PEt3)3(H) (Ir(1)-C(1) 2.085(6) A and Ir(1)-C(5)
2.189(6) A).19a All these parameters strongly support a cyclo-
˚
hexadiene moiety in complex 1.
The NMR spectroscopic data of 1 are consistent with the
structure shown in Figure 1. In the 1H NMR spectrum, the
characteristic IrCH resonance appeared at δ = 9.4 ppm and
the signals of the two protons bonded to C5 were observed at
δ = 1.9 ppm as a triplet. The signals of protons on C3 and C4
were at δ = 5.8 and 4.9 ppm, respectively, which are typical
for olefinic compounds. The 31P{1H} NMR spectrum showed
a triplet at δ = 18.9 ppm attributed to CPPh3, and the signals
for IrPPh3 were observed at δ = -3.1 ppm as a doublet, with a
P-P coupling constant of 6.5 Hz. In the 13C{1H} NMR
spectrum the metallacycle carbon signals were observed
at δ = 175.1 (C1), 111.0 (C2), 124.4 (C3), 131.9 (C4), and
3.4 (C5) ppm, respectively.
˚
tion of 0.0457 A from the rms planes of the best fit. The
coordination around the iridium atom can be rationalized as
an octahedron with the phosphorus atoms of PPh3 ligands
occupying trans positions (P(1)-Ir(1)-P(2) = 176.5(1)°),
while one chloride atom and one carbonyl ligand are cis
to each other (Cl(1)-Ir(1)-C(6) = 98.9(1)°). As expected,
there is a clear alternation in the C-C bond lengths around
the six-membered ring; C(1)-C(2) and C(3)-C(4) are
˚
1.335(6) and 1.330(6) A, respectively, which are typical
CdC double-bond lengths, while C(2)-C(3) and C(4)-C(5)
The formation of 1 involves nucleophilic attack of PPh3 on
the coordinated alkyne, as is the case in our previous
reactions,12a which is then followed by hydride insertion to
give cyclometalated intermediate C. Apparently, dehydra-
tion occurred to form the iridacyclohexadiene 1 (Scheme 2).
Although metallacyclohexadienes have been proposed
as key intermediates in many reactions,20 the strategies
employed to construct stable metallacyclohexadienes of
general structure related to 1 are still rare.19,21-25 The
first isolable example of metallacyclohexadiene complex
(12) (a) Xia, H.; He, G.; Zhang, H.; Wen, T. B.; Sung, H. H. Y.;
Williams, I. D.; Jia, G. J. Am. Chem. Soc. 2004, 126, 6862. (b) Gong, L.;
Lin, Y.; He, G.; Zhang, H.; Wang, H.; Wen, T. B.; Xia, H. Organometallics
2008, 27, 309. (c) Gong, L.; Lin, Y.; Wen, T. B.; Zhang, H.; Zeng, B.; Xia, H.
Organometallics 2008, 27, 2584. (d) Zhang, H.; Wu, L.; Lin, R.; Zhao, Q.;
He, G.; Yang, F.; Wen, T. B.; Xia, H. Chem.;Eur. J. 2009, 15, 3546.
(13) (a) Liu, B.; Xie, H.; Wang, H.; Wu, L.; Zhao, Q.; Chen, J.; Wen,
T. B.; Cao, Z.; Xia, H. Angew. Chem., Int. Ed. 2009, 48, 5461. (b) Wang,
T.; Li, S.-H.; Zhang, H.; Lin, R.; Han, F.; Lin, Y.; Wen, T. B.; Xia, H. Angew.
Chem., Int. Ed. 2009, 48, 6453.
(14) Lin, Y.; Gong, L.; Xu, H.; He, X.; Wen, T. B.; Xia, H.
Organometallics 2009, 28, 1524.
(15) Gong, L.; Wu, L.; Lin, Y.; Zhang, H.; Yang, F.; Wen, T. B.; Xia,
H. Dalton Trans. 2007, 4122.
(18) Dean, J. A. Lange’s Handbook of Chemistry; McGraw-Hill:
New York, 1998; Chapter 4.39.
(19) (a) Bleeke, J. R.; Peng, W.-J. Organometallics 1987, 6, 1576. (b)
Bleeke, J. R.; Rohde, A. M.; Boorsma, D. W. Organometallics 1993, 12, 970.
(16) Czepa, A.; Hofmann, T. J. Agric. Food. Chem. 2004, 52, 4508.
€
(17) Olgemoller, B.; Bauer, H.; Beck, W. J. Organomet. Chem. 1981,
213, C57.

2906 Organometallics, Vol. 29, No. 13, 2010
Lin et al.
Scheme 2. Possible Mechanism for the Formation of
Iridacyclohexadiene 1
Scheme 3. Reaction of Iridacyclohexadiene 1 with Bromine
[PtC(Ph)dC(Ph)C(Ph)dCHCH2](PPh3)2 was obtained by
Hughes from the ring-opening reactions of 3-vinyl-1-cyclopro-
penes with Pt(η2-C2H4)(PPh3)2.22a The approach has also been
extended to the synthesis of iridacyclohexadiene22b and rhoda-
cyclohexadiene.22c Bleeke et al. have provided a different route
utilizing pentadienide as the source of ring carbon atoms for
synthesis of iridacyclohexadiene species,19 which can be con-
verted to the first examples of iridabenzenes.23 An unprecedented
method for iridacyclohexadienes derived from the [2þ2þ1]
cyclotrimerization between alkynes was also reported.24 A nu-
cleophilic aromatic addition reaction of iridabenzenes or the
hydrogenation of the iridacycloheptatrienes can also lead to
iridacyclohexadienes.25 We documented here another conveni-
ent route to construct iridacyclohexadiene. It is also worth noting
that complex 1 shows excellent air and thermal stability, in view
of the fact that the solid sample remains almost unchanged when
heated at 100 °C under air for 5 h.
Reaction of Iridacyclohexadiene 1 with Bromine. With the
intent of exploring the reactivity of the available iridacyclo-
hexadiene, we have tried the reactions of complex 1 with many
reagents such as HBF4, Cs2CO3, and PMe3; no obvious
conversion was observed at room temperature. However,
the reaction of complex 1 with 1 equiv of bromine afforded
the iridacyclopentadiene2, which could subsequently undergo
intramolecular C(sp2)-C(sp3) coupling to give the fused
iridacycle complex 3 in the presence of excess bromine.
A solution containing 1 and bromine in CH2Cl2 with a 1:1
molar ratio was stirred at room temperature for 6 h to give a
light yellow solution, from which the iridacyclopentadiene
[Ir(CHdC(PPh3)CHdC(CH2Br))Cl(CO)(PPh3)2]BF4 (2) could
be isolated in 65% yield. (Scheme 3).
An X-ray single-crystal diffraction experiment has clar-
ified the structure of 2. As shown in Figure 2, the geometry of
the iridium center can be viewed as an octahedron in which
the six coordination sites are occupied by C1 and C4, one
chloride atom, one carbon atom of carbonyl ligand, and two
phosphorus atoms of the phosphine ligands. The distances of
˚
˚
Ir(1)-C(1) (2.070(8) A) and Ir(1)-C(4) (2.068(7) A) agree
with the average for 318 recorded observation for Ir-C-
(vinyl) bonds (2.052 with a SD of 0.048 A).26 The C(1)-C(2)
˚
˚
and C(3)-C(4) bonds length of 1.342(10) and 1.380(11) A,
respectively, indicate a C-C double bond, while the C(2)-C-
˚
(3) bond length is 1.462(11) A, supporting a C-C single
bond.18
The solution NMR spectroscopic data of 2 are consistent
with its solid-state structure. Particularly, the 1H NMR
spectrum of 2 showed the characteristic proton IrCH signal
at δ = 9.1 ppm, and the proton signal on C3 was at δ = 6.6
ppm. The two protons of the exocyclic -CH2Br group were
observed at δ = 2.6 ppm as a broad peak. The 31P{1H} NMR
spectrum showed a doublet at δ = -10.5 ppm (4J(PP) = 4.8
Hz, IrPPh3) for the two equivalent phosphine ligands and a
triplet at δ = 12.0 ppm (4J(PP) = 4.8 Hz, CPPh3) attributed
to the phosphonium group on the ring structure. The NMR
data seem to implicate the presence of a resonance contri-
butor 2A to the structure of 2 shown in Scheme 4.27
In fact, metallacyclopentadienes have always been in-
voked as key intermediates for cyclotrimerization of alkynes,
and their reactions toward alkynes have been studied exten-
sively.28 Especially, various organic compounds obtained
from metallacyclopentadienes have been widely studied.24,29
Iridacyclopentadiene 2 with an exocyclic -CH2Br group
(20) See for examples: (a) Wang, Q.; Liu, L.; Lin, C.; Sun, H.; Zhang,
W.-X.; Xi, Z. Dalton Trans. 2009, 10433. (b) Wen, T. B.; Hung, W. Y.;
Sung, H. H.-Y.; Zhou, Z.; Williams, I. D.; Jia, G. Eur. J. Inorg. Chem. 2007,
ꢀ
ꢀ
2693. (c) Paneque, M.; Poveda, M. L.; Rendon, N.; Alvarez, E.; Carmona, E.
Eur. J. Inorg. Chem. 2007, 2711. (d) Hughes, R. P.; Trujillo, H. A.; Gauri,
A. J. Organometallics 1995, 14, 4319.
(21) (a) Hughes, R. P.; Trujillo, H. A.; Egan, J. W., Jr.; Rheingold,
A. L. J. Am. Chem. Soc. 2000, 122, 2261, and references therein. (b) Yu, T.;
Sun, X.; Wang, C.; Deng, L.; Xi, Z. Chem.;Eur. J. 2005, 11, 1895. (c) Xi,
Z.; Fischer, R.; Hara, R.; Sun, W.-H.; Obora, Y.; Suzuki, N.; Nakajima, K.;
Takahashi, T. J. Am. Chem. Soc. 1997, 119, 12842. (d) Xi, Z.; Huo, S.;
Noguchi, Y.; Takahashi, T. Chem. Lett. 2000, 218.
(22) (a) Grabowski, N. A.; Hughes, R. P.; Jaynes, B. S.; Rheingold,
A. L. J. Chem. Soc., Chem. Commun. 1986, 1694. (b) Hughes, R. P.;
Trujillo, H. A.; Rheingold, A. L. J. Am. Chem. Soc. 1993, 115, 1583. (c)
Egan, J. W.; Hughes, R. P.; Rhelngold, A. L. Organometallics 1987, 6, 1578.
(23) (a) Bleeke, J. R.; Xie, Y.-F.; Peng, W.-J.; Chiang, M. J. Am.
Chem. Soc. 1989, 111, 4118. (b) Bleeke, J. R. Acc. Chem. Res. 1991, 24,
271. (c) Bleeke, J. R.; Behm, R.; Xie, Y.-F.; Chiang, M. Y.; Robinson, K. D.;
Beatty, A. M. Organometallics 1997, 16, 606.
(26) Based on a search of the Cambridge Structural Database, CSD
version 5.31 (November 2009)
(27) (a) Albright, T. A.; Gordon, M. D.; Freeman, W. J.; Schweizer,
E. E. J. Am. Chem. Soc. 1976, 98, 6249. (b) Ackermann, M.; Pascariu, A.;
€
Hocher, T.; Siehl, H.-U.; Berger, S. J. Am. Chem. Soc. 2006, 128, 8434.
(28) Chin, C. S.; Lee, H. Chem.;Eur. J. 2004, 10, 4518, and refs 3
and 5 therein.
(24) Chin, C. S.; Kim, M.; Lee, H.; Noh, S.; Ok, K. M. Organome-
(29) (a) Liu, J.; Zhang, W.-X.; Guo, X.; Hou, Z.; Xi, Z. Organome-
tallics 2007, 26, 6812. (b) Takahashi, T.; Kuzuba, Y.; Kong, F.; Nakajima, K.;
Xi, Z. J. Am. Chem. Soc. 2005, 127, 17188. (c) Xi, Z.; Sato, K.; Gao, Y.; Lu,
J.; Takahashi, T. J. Am. Chem. Soc. 2003, 125, 9568. (d) Zhao, C.; Li, P.;
Cao, X.; Xi, Z. Chem.;Eur. J. 2002, 8, 4292. (e) O'Connor, J. M.; Closson,
A.; Hiibner, K.; Merwin, R.; Gantzel, P.; Roddick, D. M. Organometallics
2001, 20, 3710.
tallics 2002, 21, 4785.
(25) (a) Paneque, M.; Posadas, C. M.; Poveda, M. L.; Rendon, N.;
ꢀ
Santos, L. L.; Alvarez, E.; Salazar, V.; Mereiter, K.; Onate, E. Organo-
ꢀ
~
metallics 2007, 26, 3403. (b) Paneque, M.; Posadas, C. M.; Poveda, M. L.;
ꢀ
~
Rendon, N.; Salazar, V.; Onate, E.; Mereiter, K. J. Am. Chem. Soc. 2003,
125, 9898.

Article
Organometallics, Vol. 29, No. 13, 2010 2907
Figure 3. Molecular structure of complex 3 (50% probability
thermal ellipsoids). Counteranion and the solvent molecules as
well as some of the hydrogen atoms are omitted for clarity.
Figure 2. Molecular structure of complex 2 (50% probability
thermal ellipsoids). Counteranion and the solvent molecules as
well as some of the hydrogen atoms are omitted for clarity.
˚
˚
Selected bond distances [A] and angles [deg]: Ir(1)-C(1) =
Selected bond distances [A] and angles [deg]: Ir(1)-C(1) =
2.052(13), Ir(1)-C(4)=2.082(14), C(1)-C(2)=1.358(18), C(2)-
C(3)=1.448(18), C(3)-C(4)=1.290(17), C(4)-C(5)=1.485(19),
O(1)-C(6) = 1.141(17), Ir(1)-C(6) = 1.920(18), Ir(1)-P(2) =
2.389(4), Ir(1)-P(1)=2.335(4), Br(1)-C(3)=1.942(12), Br(2)-
C(5) = 1.895(14), C(5)-C(136) = 1.55(2), C(1)-Ir(1)-C(4) =
77.9(5), C(2)-C(1)-Ir(1)=116.7(10), C(1)-C(2)-C(3)=111.6-
(12), C(4)-C(3)-C(2)=120.1(12), C(3)-C(4)-Ir(1)=113.6(10),
P(2)-Ir(1)-P(1)=176.5(2), C(4)-C(5)-C(136)=114.2(12).
constant of 295.1 Hz. In the 13C{1H} NMR spectrum, the
cyclopentadiene moiety resonances appeared at δ = 198.4
(C1), 122.3 (C2), 116.4 (C3), and 149.2 (C4) ppm,
respectively. The CO resonance was observed at δ = 174.0
ppm.
2.070(8), Ir(1)-C(4) = 2.068(7), C(1)-C(2) = 1.342(10), C-
(2)-C(3) = 1.462(11), C(3)-C(4) = 1.380(11), C(4)-C(5) =
1.477(12), O(1)-C(6) = 1.140(9), Ir(1)-P(2) = 2.368(2), Ir(1)-
P(1)= 2.378(2), Br(1)-C(5)=1.916(8), C(1)-Ir(1)-C(4)= 79.4(3),
C(2)-C(1)-Ir(1) = 115.4(6), C(1)-C(2)-C(3) = 115.4(7), C(4)-
C(3)-C(2) =116.0(7), C(3)-C(4)-Ir(1) = 113.7(6), P(2)-Ir-
(1)-P(1) = 173.6(1).
Scheme 4. Resonance Structures of 2
A plausible mechanism for the formation of complexes 2
and 3 is proposed in Scheme 5. Electrophilic abstraction of
the alkyl carbon (C5) of complex 1 by Br2 followed by
coordination of the double bond to the Ir center gives an
η2-olefin coordinated iridacycle D. Dissociation of a PPh3
ligand and oxidative addition of the vinyl C-H bond
produces a monophosphine metal-hydride intermediate E,
which then undergoes deprotonation of the hydrido ligand
and recoordination of a PPh3 ligand to afford the iridacy-
clopentadiene 2. Electrophilic substitution reaction of 2 with
bromine could produce first intermediate F and then give
bromine-substituted complex G by deprotonation. Dissocia-
tion of a PPh3 ligand from G can provide a vacant site for the
oxidative addition of the ortho phenyl C-H bond of the PPh3
ligand on Ir to form the hydrido intermediate H. Ortho-
metalation of the aryl ring of a phosphine attached to a metal
is a widely occurring reaction, and this type of reaction is one
of the earliest examples of metal activation of a C-H bond.30
The hydride in H can be removed by the excess Br2 in the
form of HBr via an electrophilic subtraction. Again, the
C-H bond of the exocyclic -CH2Br group can be activated
to give an agostic species I. Subsequent abstraction of the
agostic proton by counterion Br- results in a seven-coordinated
iridium species J. Eventually, reductive elimination of the two
might be used as a potential starting material for the synth-
esis of organic species.
Interestingly, the reaction of iridacyclohexadiene 1 with
an excess (10 equiv) of bromine at room temperature
afforded the fused iridacycle complex [Ir(CHdC(PPh3)
C(Br)dC(CHBr))(P(C6H4)Ph2)Cl(CO)PPh3]Br3 (3) in an
isolated yield of 81%. Treatment of isolated iridacyclopenta-
diene 2 with an excess of bromine also led to the formation of 3.
As shown in Figure 3, complex 3 contains an iridacyclo-
pentadiene moiety that is similar to that of complex 2.
However, the coupling between a phenyl of a PPh3 ligand
and the exocyclic -CH2Br group occurred to construct a six-
membered ring, which is fused with cyclopentadiene. The
˚
single-bond distance for Br(2)-C(5) (1.895(14) A) is com-
˚
parable with that of Br(1)-C(5) (1.916(8) A) in complex 2.
˚
The bond length of Br(1)-C(3) (1.942(12) A) clearly indi-
cates that bromination has occurred at C(3). The C(136)-C-
18
˚
(5) bond distance of 1.55(2) A is a typical C-C single bond.
The 1H NMR spectrum of 3 in CD2Cl2 showed the
characteristic IrCH proton signal at δ = 9.7 ppm. The
proton signal on C5 was at δ = 7.0 ppm according to
1H-13C HMQC. In the 31P{1H} NMR spectrum, the signal
at δ = 16.6 (dd, 4J(PP) = 6.0 Hz, 4J(PP) = 2.8 Hz, CPPh3)
ppm was attributed to the phosphonium group on the ring
structure. The two phosphine ligand signals appeared at δ =
1.6 and -17.1 ppm, respectively, with a large P-P coupling
(30) (a) Ryabov, A. D. Chem. Rev. 1990, 90, 403. (b) Dehand, J.;
Pfeffer, M. Coord. Chem. Rev. 1976, 18, 327. (c) Bruce, M. I. Angew.
Chem., Int. Ed. Engl. 1977, 16, 73. (d) Cooper, A. C.; Huffman, J. C.;
Caulton, K. G. Organometallics 1997, 16, 1974. (e) Huang, Y.-H.; Huang,
W.-W.; Lin, Y.-C.; Huang, S.-L. Organometallics 2010, 29, 38.

2908 Organometallics, Vol. 29, No. 13, 2010
Scheme 5. Plausible Mechanism for the Formation of Complexes 2 and 3
Lin et al.
hydrocarbyl ligands from the Ir center and recoordination of a
PPh3 ligand afford the C(sp2)-C(sp3) coupling product 3.
In an attempt to get some insight into the mechanism for
the formation of 3, we have tried to monitor the reaction of 2
with different amounts of bromine by NMR. Upon treat-
ment of 2 with 1 or 2 equiv of bromine at room temperature,
no appreciable reaction could be observed even after 3 days.
When the reaction of 2 with 3 equiv of bromine in CDCl3 was
monitored by 31P{1H} NMR, two sets of new 31P signals at
δ = 13.0(t), -14.3(d) ppm (J(PP) = 12.0 Hz) and δ =
11.8(t), -9.6(d) ppm (J(PP) = 4.5 Hz) started to appear
simultaneously in 6 h, indicating the formation of a small
amount of two new species with two equivalent phosphine
ligands on metal centers, respectively. However, the reaction
proceeded very slowly. As can be indicated by the in situ
31P{1H} NMR spectra, complex 2 was still the dominant
species (∼85%) in the solution when the reaction was almost
suspended after 2 days. Although further increasing the ratio
of bromine could speed up the reaction at the early stage, the
two newly formed species could undergo further reaction to
evolve to the final product 3 in the solution, and the 31P{1H}
NMR spectra for the reaction process became even more
complicated. Therefore, it is difficult to isolate and charac-
terize the intermediates from the reaction. Nevertheless, the
pattern of the 31P{1H} NMR signals for the two above-
mentioned detectable intermediates supported that bromine
substitution at C(3) of 2 should take place before the ortho-
metalation of the PPh3 ligand for the formation of 3.
Transformation of I to J can be formally viewed as an
electrophilic substitution, in which the positively charged
metal center acts as the electrophile and the agostic proton is
subtracted by the Br- counterion. Similar roles played by
Cl-, which can abstract an agostic H in the electrophilic
substitution mechanism, have already been postulated for
the reaction of CH4 with (bpym)PtCl2,31a-c the cycloisome-
rizations of bromoallenyl ketones with Au(PH3)Cl,31d as
well as for the isomerization of intramolecularly coordinated
η2-allene complex [Os{CHdC(PPh3)C(CH3)=η2-CdCH2}-
(PhCN)2(PPh3)2]Cl2 to osmabenzene [Os{CHC(PPh3)C(CH3)-
CHCH}(PhCN)2(PPh3)2]Cl2.31e
It is worthy to note that, in principle, both C-H and C-Br
bonds in the -CH2Br group of H can be possibly activated.
Apparently, only C-H activation occurred in our reaction,
however. Selective C-H activation in the presence of C-X
bonds has been reported for Pd, Rh, Au, and Ir system.32-35
The reactions of the (PNP)Ir fragment with haloarenes
(32) Selective C-H activation for Pd: (a) Zaitsev, V. G.; Daugulis, O.
J. Am. Chem. Soc. 2005, 127, 4156. (b) Kalyani, D.; Deprez, N. R.; Desai,
L. V.; Sanford, M. S. J. Am. Chem. Soc. 2005, 127, 7330.
(33) Selective C-H activation for Rh: (a) Gatard, S.; Celenligil-
Cetin, R.; Guo, C.; Foxman, B. M.; Ozerov, O. V. J. Am. Chem. Soc.
2006, 128, 2808. (b) Gatard, S.; Guo, C.; Foxman, B. M.; Ozerov, O. V.
Organometallics 2007, 26, 6066.
(34) Selective C-H activation for Au: Fuchita, Y.; Utsunomiya, Y.;
Yasutake, M. J. Chem. Soc., Dalton Trans. 2001, 16, 2330.
(35) Selective C-H activation for Ir: (a) Zhu, Y.; Fan, L.; Chen,
C.-H.; Finnell, S. R.; Foxman, B. M.; Ozerov, O. V. Organometallics
2007, 26, 6701. (b) Fan, L.; Parkin, S.; Ozerov, O. V. J. Am. Chem. Soc.
2005, 127, 16772. (c) Chotana, G. A.; Rak, M. A.; Smith, M. R., III. J. Am.
Chem. Soc. 2005, 127, 10539. (d) Ben-Ari, E.; Gandelman, M.; Rozenberg,
H.; Shimon, L. J. W.; Milstein, D. J. Am. Chem. Soc. 2003, 125, 4714. (e)
Tellers, D. M.; Yung, C. M.; Arndtsen, B. A.; Adamson, D. R.; Bergman,
R. G. J. Am. Chem. Soc. 2002, 124, 1400. (f) Ishiyama, T.; Takagi, J.; Ishida,
K.; Miyaura, N.; Anastasi, N. R.; Hartwig, J. F. J. Am. Chem. Soc. 2002, 124,
390. (g) Cho, J.-Y.; Tse, M. K.; Holmes, D.; Maleczka, R. E., Jr.; Smith, M. R.,
III. Science 2002, 295, 305.
(31) (a) Kua, J.; Xu, X.; Periana, R. A.; Goddard, W. A., III.
Organometallics 2002, 21, 511. (b) Xu, X.; Kua, J.; Periana, R. A.; Goddard,
W. A., III. Organometallics 2003, 22, 2057. (c) Xu, X.; Fu, G.; Goddard,
W. A., III.; Periana, R. A. Stud. Surf. Sci. Catal. 2004, 147, 505. (d) Xia, Y.;
Dudnik, A. S.; Gevorgyan, V.; Li, Y. J. Am. Chem. Soc. 2008, 130, 6940. (e)
Gong, L.; Chen, Z.; Lin, Y.; He, X.; Wen, T. B.; Xu, X.; Xia, H. Chem.;Eur.
J. 2009, 15, 6258.

Article
Organometallics, Vol. 29, No. 13, 2010 2909
showed that C-H activation was favored kinetically,
whereas the C-X (X = Cl, Br) activation was preferred
thermodynamically.35b It has also been reported that C-H
activation in haloarenes is more likely to be successful with Ir
(5d metal) than Rh (4d metal).33a
[Ir(CHdC(PPh3)CHdCHCH2)Cl(CO)(PPh3)2]BF4 (1).
mixture of [IrHCl(CO)(PPh3)3]BF4 (500 mg, 0.44 mmol) and
HCtCCH(OH)CHdCH2 (37 mg, 0.45 mmol) in THF (10 mL)
was stirred at room temperature for 3 days to give a white
suspension. The solid was collected by filtration, washed with
THF (2 ꢁ 2 mL) and Et2O (10 mL), and then dried under
vacuum (yield: 295 mg, 56%). 1H NMR (CDCl3, 400.1 MHz): δ
9.4 (d, 3J(PH) = 29.2 Hz, 1 H, IrCH), 6.8-7.8 (m, 45 H, PPh3),
5.8 (dd, 3J(PH) = 9.6 Hz, 3J(HH) = 9.6 Hz, 1 H, IrCHCCH),
4.9 (m, 1 H, IrCH2CH), 1.9 (t, 3J(PH) = 11.6 Hz, 2 H, IrCH2)
ppm. 31P{1H} NMR (CDCl3, 162.0 MHz): δ 18.9 (t, 4J(PP) =
6.5 Hz, CPPh3), -3.1 (d, 4J(PP) = 6.5 Hz, IrPPh3) ppm.
13C{1H} NMR (CD2Cl2, 75.5 MHz): δ 175.1 (td, 2J(PC) =
A
It should also be mentioned that C-H activation and
C-C reductive elimination through an Ir(V) intermediate
have been recently supported both theoretically and
experimentally.36 In our case, the related process of C-H
activation steps in the formation of complex 3 is probably
promoted by the synergistic effects of iridium and bromine.
Iridium can readily undergo cyclometalation and has proven
effective in catalytic reactions involving C-H activation
through chelation assistance.37 Bromine is used as a strong
oxidant and facilitates the abstraction of the hydrido ligand,
which, in turn, is favorable for the subsequent electrophilic
C-H activation. Additionally, previous reports of C-C
reductive elimination from the iridium center usually involve
vinyl-vinyl or vinyl-acyl to form a conjugated system,
while C(sp2)-C(sp3) reductive elimination reactions from
iridium are still scarce.6
2
11.5 Hz, J(PC) = 3.5 Hz, IrCCH), 174.6 (m, CO), 131.9 (d,
2
3J(PC) = 11.8 Hz, IrCHC(PPh3)CHCH), 124.4 (d, J(PC) =
21.1 Hz, IrCHCCH), 111.0 (dt, 1J(PC) = 71.7 Hz, 3J(PC) = 4.7
2
Hz, IrCHC(PPh3)), 3.4 (t, J(PC) = 3.5 Hz, IrCH2), 110.0-
136.0 (m, PPh3) ppm. Anal. Calcd (%) for C60H50ClOIrP3BF4:
C 60.33, H 4.22. Found: C 60.46, H 4.58.
[Ir(CHdC(PPh3)CHdC(CH2Br))Cl(CO)(PPh3)2]BF4 (2). A
mixture of [Ir(CHdC(PPh3)CHdCHCH2)Cl(CO)(PPh3)2]-
BF4 (1) (500 mg, 0.42 mmol) and Br2 (22 μL, 0.43 mmol) in
CH2Cl2 (15 mL) was stirred at room temperature for 24 h to give
a yellow suspension. The volume of the solution was reduced to
approximately 1 mL under vacuum. Addition of diethyl ether
(10 mL) to the solution gave a yellow precipitate, which was
collected by filtration, washed with diethyl ether (2 ꢁ 5 mL), and
dried under vacuum. The residue was purified by column
chromatography (neutral alumina, eluent: dichloromethane/
Conclusion
The thermally stable iridacyclohexadiene [Ir(CHd
C(PPh3)CHdCHCH2)Cl(CO)(PPh3)2]BF4 (1) can be easily
synthesized from the reaction of readily accessible HCt
CCH(OH)CHdCH2 with [IrHCl(CO)(PPh3)3]BF4. Reac-
tion of complex 1 with 1 equiv of bromine leads to the
formation of iridacyclopentadiene [Ir(CHdC(PPh3)CHd
C(CH2Br))Cl(CO)(PPh3)2]BF4 (2). When excess bromine is
provided, iridacyclopentadiene 2 can subsequently undergo
intramolecular C(sp2)-C(sp3) coupling between the exo-
cyclic -CH2Br group and a phenyl of a PPh3 ligand at
the iridium, which results in the formation of the fused
1
acetone, 12:1) (yield: 345 mg, 65%). H NMR (CDCl3, 400.1
MHz): δ 9.1 (d, 3J(PH) = 20.4 Hz, 1 H, IrCH), 6.9-7.9 (m, 45
H, PPh3), 6.6 (br, 1 H, IrCHC(PPh3)CH), 2.6 (br, 2 H, CH2Br)
ppm. 31P{1H} NMR (CDCl3, 162.0 MHz): δ 12.0 (t, 4J(PP) =
4.8 Hz, CPPh3), -10.5 (d, 4J(PP) = 4.8 Hz, IrPPh3). Anal.
Calcd (%) for C60H49IrOClBrP3BF4: C 56.60, H 3.88. Found: C
57.02, H 4.24.
[Ir(CHdC(PPh3)C(Br)dC(CHBr))(P(C6H4)Ph2)Cl(CO)PPh3]-
Br3 (3). Method A: A mixture of [Ir(CHdC(PPh3)CHd
CHCH2)Cl(CO)(PPh3)2]BF4 (1) (500 mg, 0.42 mmol) and Br2
(215 μL, 4.20 mmol) in CH2Cl2 (10 mL) was stirred at room
temperature for 3 days to give a yellow suspension. The volume
of the solution was reduced to approximately 1 mL under
vacuum. Addition of diethyl ether (10 mL) to the solution gave
a yellow precipitate, which was collected by filtration, washed
with diethyl ether (2 ꢁ 5 mL), and dried under vacuum (yield: 509
mg, 81%). Method B: A mixture of [Ir(CHdC(PPh3)CHd
C(CH2Br))Cl(CO)(PPh3)2]BF4 (2) (500 mg, 0.39 mmol) and Br2
(200 μL, 3.90 mmol) in CH2Cl2 (15 mL) was stirred at room
temperature for 3 days to give a yellow suspension. The volume
of the solution was reduced to approximately 1 mL under
vacuum. Addition of diethyl ether (10 mL) to the solution gave
a yellow precipitate, which was collected by filtration, washed
with diethyl ether (2 ꢁ 5 mL), and dried under vacuum (yield: 492
mg, 83%). 1H NMR (CD2Cl2, 300.1 MHz): δ 9.7 (dd, 3J(PH) =
20.2 Hz, 3J(PH) = 3.0 Hz, 1 H, IrCH), 7.0 (1 H, CHBr, obscured
by the phenyl signals and confirmed by 1H-13C HMQC),
6.6-7.9 (m, 44 H, PPh3) ppm. 31P{1H} NMR (CD2Cl2, 121.5
MHz): δ 16.6 (dd, 4J(PP) = 6.0 Hz, 4J(PP) = 2.8Hz, CPPh3), 1.6
(dd, 2J(PP) = 295.1 Hz, 4J(PP) = 2.8 Hz, IrPPh3), -17.1 (dd,
iridacycle complex [Ir(CHdC(PPh3)C(Br)dC(CHBr))(P(C6
H4)Ph2)Cl(CO)PPh3]Br3 (3). The proposed mechanism for
the formation of complex 3 from 1 involves triple C-H acti-
vation as well as a rare C(sp2)-C(sp3) reductive elimination.
Experimental Section
General Considerations. All manipulations were carried out at
room temperature under a nitrogen atmosphere using standard
Schlenk techniques, unless otherwise stated. Solvents were dis-
tilled under nitrogen from sodium benzophenone (ether, tetra-
hydrofuran) or calcium hydride (dichloromethane). The
17
starting material [IrHCl(CO)(PPh3)3]BF4 and HCtCCH-
16
(OH)CHdCH2 were synthesized by literature procedures.
All the NMR spectra were recorded with a Bruker AV300 (1H
300.1 MHz; 13C 75.5 MHz; 31P 121.5 MHz) or a Bruker AV400
(1H 400.1 MHz; 13C 100.6 MHz; 31P 162.0 MHz) spectrometer.
1H and 13C NMR chemical shifts are relative to TMS, and 31
P
NMR chemical shifts are relative to 85% H3PO4. Elemental
analyses data were obtained on an Elementar Analysensyetem
GmbH Vario EL III instrument.
4
2J(PP) = 295.1 Hz, J(PP) = 6.0 Hz, IrPPh3). 13C{1H} NMR
plus HMQC (CD2Cl2, 75.5 MHz): δ 198.4 (d, 2J(PC) = 10.1 Hz,
IrCHC(PPh3)), 174.0 (m, CO), 149.2 (d, 2J(PC) = 11.9
(36) (a) Klei, S. R.; Tilley, T. D.; Bergman, R. G. J. Am. Chem. Soc.
2000, 122, 1816, and references therein. (b) Tamura, H.; Yamazaki, H.; Sato,
H.; Sakaki, S. J. Am. Chem. Soc. 2003, 125, 16114. (c) Bernskoetter, W. H.;
Lobkovsky, E.; Chirik, P. J. Organometallics 2005, 24, 4367. (d) Esteruelas,
1
Hz, IrCC(Br)), 122.3 (d, J(PC) = 61.1 Hz, CPPh3), 116.4 (d,
3J(PC) = 22.8 Hz, IrCHC(PPh3)C(Br)), 60.7 (s, CHBr), 124.7-
139.7 (m, PPh3) ppm. Anal. Calcd (%) for C60H46IrOBr5ClP3: C
47.94, H 3.08. Found: C 48.14, H 2.68.
~
M. A.; Lahoz, F. J.; Onate, E.; Oro, L. A.; Rodríguez, L. Organometallics
1996, 15, 823.
(37) Li, X.; Chen, P.; Faller, J. W.; Crabtree, R. H. Organometallics
2005, 24, 4810, and references therein.
X-ray Crystal Structures Determination of 1, 2, and 3. Crystals
suitable for X-ray diffraction were grown from CH2Cl2 or

2910 Organometallics, Vol. 29, No. 13, 2010
Table 1. Crystal Data and Structure Refinement for 1, 2, and 3
Lin et al.
1 CH2Cl2
3
2 0.25CH2Cl2
3
3 0.5CH2Cl2
3
empirical formula
C60H50ClIrP3O
BF4 CH2Cl2
1194.43
223(2)
0.71073
triclinic
P1
14.099(3)
14.656(2)
14.670(2)
105.785(12)
96.294(13)
104.262(15)
2775.9(8)
2
1.531
1280
0.40 ꢁ 0.25 ꢁ 0.20
2.21-26.00
26 060
C60H49ClBrIrP3O BF4
3
C60H46ClBr2IrP3O
Br3 0.5CH2Cl2
1503.12
173(2)
0.71073
triclinic
P1
11.8828(9)
15.1966(13)
17.9860(14)
107.820(7)
106.346(7)
97.560(7)
2881.6(4)
2
1.781
1498
0.20 ꢁ 0.14 ꢁ 0.10
2.05-25.00
24 357
3
3
3
0.25CH2Cl2
1273.33
123(2)
3
3
fw
temperature, K
˚
radiation (Mo KR), A
cryst syst
space group
0.71073
triclinic
P1
˚
a, A
12.1921(7)
14.7377(10)
15.8268(8)
91.655(5)
91.188(4)
99.375(5)
2803.7(3)
2
1.533
1285
0.40 ꢁ 0.24 ꢁ 0.10
2.74-25.00
33 339
9859
9859/16/661
1.005
R1 = 0.0456,
wR2 = 0.1167
R1 = 0.0631,
wR2 = 0.1270
˚
b, A
˚
c, A
R, deg
β, deg
γ, deg
3
˚
V, A
Z
dcalcd, g cm-3
F(000)
cryst size, mm
θ range, deg
reflns collected
indep reflns
data/restraints/params
goodness-of-fit on F2
final R (I > 2σ(I))
10 859
10 859/0/667
0.998
R1 = 0.0331,
wR2 = 0.0769
R1 =0.0499,
wR2 =0.0828
10 132
10 132/9/652
1.039
R1 = 0.0695,
wR2 = 0.1707
R1 = 0.1169,
wR2 = 0.1816
R indices (all data)
CHCl3 solutions layered with ether or hexane for all complexes.
Selected crystals were mounted on top of a glass fiber and
transferred into a cold stream of nitrogen. Data collections were
performed on an Oxford Gemini S Ultra CCD area detector
using graphite-monochromated Mo KR radiation (λ = 0.71073
distances and Cl-C-Cl angle restraints. CCDC-761743 (1),
761744 (2), and 761745 (3) contain the supplementary crystal-
lographic data for this paper. Details on crystal data, data
collection, and refinements are summarized in Table 1.
˚
A). Multiscan or empirical absorption corrections (SADABS)
Acknowledgment. This work was financially supported
by the National Natural Science Foundation of China
(No. 20872123) and National Natural Science Funds for
Distinguished Young Scholar (No. 20925208).
were applied. All structures were solved by direct methods,
expanded by difference Fourier syntheses, and refined by full-
matrix least-squares on F2 using the Bruker SHELXTL-97
program package. Non-H atoms were refined anisotropically
unless otherwise stated. Hydrogen atoms were introduced at
their geometric positions and refined as riding atoms. The
disordered CH2Cl2 solvent in 2 was refined isotropically using
fixed C-Cl distances and Cl-C-Cl angle restraints with site
occupancy of 0.25. The hemisolvating CH2Cl2 molecule in 3 was
refined with isotropic thermal parameters using fixed C-Cl
Supporting Information Available: X-ray crystallographic
files (CIF). ORTEP views of the whole structure of 1, 2, and 3,
including the anions and the solvent molecules. These materials
are available free of charge via the Internet at http://pubs.
acs.org.