Formation of four conjugated osmacyclic species in a one-pot reaction

Article abstract of DOI:10.1021/om8001558

Treatment of HC≡CCH(OH)CH=CH₂ with OsCl ₂(PPh₃)₃ in THF produced the η²-allyl alcohol osmacycle OsCl₂(PPh₃) ₂(CH=C(PPh₃)CH(OH)CH=CH₂) (2) with poor solubility and low stability, which underwent a ligand substitution reaction with PMe₃ to give the more stable analogue [OsCl-(PMe ₃)₃(CH=C(PPh₃)CH(OH)CH=CH₂)]Cl (3). Heating the suspension of 2 in CH₂Cl₂ led to the formation of four interesting conjugated osmacycles in one pot, including the osmabenzene OsCl₂(PPh₃)₂(CHC(PPh₃)CHCHCH) (4), the cyclic osmium η²-allene complex OsCl₂(PPh ₃)2(CH=C(PPh₃)CH=C=CH₂) (5), the osmafuran OsCl₂(PPh₃(CHC(PPh₃)C(CH₂CH ₃)O) (6), and the α,β-unsaturated ketone complex OsCl ₂(PPh₃)₂(CH=C(PPh₃)C(O)C=CH ₂) (7). All of the four products could also be produced in higher yield under appropriate conditions.

Full text of DOI:10.1021/om8001558

2584
Organometallics 2008, 27, 2584–2589
Formation of Four Conjugated Osmacyclic Species in a One-Pot
Reaction
Lei Gong, Yumei Lin, Ting Bin Wen, Hong Zhang, Birong Zeng, and Haiping Xia*
Department of Chemistry, College of Chemistry and Chemical Engineering, and State Key Laboratory for
Physical Chemistry of Solid Surfaces, Xiamen UniVersity, Xiamen, 361005, People’s Republic of China
ReceiVed February 20, 2008
Treatment of HCt CCH(OH)CHdCH2 with OsCl2(PPh3)3 in THF produced the η2-allyl alcohol
osmacycle OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CHdCH2) (2) with poor solubility and low stability, which
underwent a ligand substitution reaction with PMe3 to give the more stable analogue [OsCl-
(PMe3)3(CHdC(PPh3)CH(OH)CHdCH2)]Cl (3). Heating the suspension of 2 in CH2Cl2 led to the
formation of four interesting conjugated osmacycles in one pot, including the osmabenzene
OsCl2(PPh3)2(CHC(PPh3)CHCHCH) (4), the cyclic osmium η2-allene complex OsCl2(PPh3)2(CHd
C(PPh3)CHdCdCH2) (5), the osmafuran OsCl2(PPh3)2(CHC(PPh3)C(CH2CH3)O) (6), and the R,ꢀ-
unsaturated ketone complex OsCl2(PPh3)2(CHdC(PPh3)C(O)CdCH2) (7). All of the four products could
also be produced in higher yield under appropriate conditions.
Scheme 1
Introduction
Metallacycles containing transition metals1–5 are an interesting
class of compounds, due to their special reactivity and properties
compared with those of similar cyclic organics. Over the past
several decades, rapid progress has been made in research on
the syntheses and properties of some archetypical aromatic
metallacycles.
As one class of six-membered delocalized metallacycles
analogous to benzene, metallabenzenes1–3 have attracted
considerable attention, both experimentally and theoretically,
in recent years. Since the first metallabenzene (osmabenzene)
was isolated and characterized in 1982,2a both synthetic
methods and different aromatic topologies of metallabenzenes
have been developed. In contrast, osmabenzenes, as the
pioneers of metallabenzenes, are still limited to only a few
reports.2
* To whom correspondence should be addressed. Fax: (+86)592-218-
6628. E-mail: hpxia@xmu.edu.cn.
(1) For recent reviews, see: (a) Bleeke, J. R. Chem. ReV. 2001, 101,
1205. (b) Landorf, C. W.; Haley, M. M. Angew. Chem., Int. Ed. 2006, 45,
3914. (c) Bleeke, J. R. Acc. Chem. Res. 2007, 40, 1035. (d) Wright, L. J.
Dalton Trans. 2006, 1821.
(2) Some examples of osmabenzenes: (a) Elliott, G. P.; Roper, W. R.;
Waters, J. M. J. Chem. Soc., Chem. Commun. 1982, 811. (b) Hung, W. Y.;
Zhu, J.; Wen, T. B.; Yu, K. P.; Sung, H. H. Y.; Williams, I. D.; Lin, Z.;
Jia, G. J. Am. Chem. Soc. 2006, 128, 13742. (c) Rickard, C. E. F.; Roper,
W. R.; Woodgate, S. D.; Wright, L. J. Angew. Chem., Int. Ed. 2000, 39,
750. (d) Xia, H. P.; He, G. M.; Zhang, H.; Wen, T. B.; Sung, H. H. Y.;
Williams, I. D.; Jia, G. J. Am. Chem. Soc. 2004, 126, 6862. (e) Gong, L.;
Lin, Y.; He, G.; Zhang, H.; Wang, H.; Wen, T. B.; Xia, H. Organometallics
2008, 27, 309.
Recently, we have reported some interesting reactions of the
highly unsaturated C5 dialkyne HCt CCH(OH)Ct CH with
transition-metal-containing complexes bearing phosphine ligands,
which led to the formation of some stable metallacycles,
including osmabenzenes,2d,e ruthenabenzenes,3e,f and bridged
iridacycles.5d These reactions were initiated by the coordination
of the alkyne to the metal center and nucleophilic attack of the
phosphines on the coordinated alkyne. All of the products of
the above reactions contained bulky phosphoniums in the
structures, which acted as protecting groups and thus improved
their stability to some extent.
(3) Some examples of metallabenzenes containing other metals: (a)
Landorf, C. W.; Jacob, V.; Weakley, T. J. R.; Haley, M. M. Organometallics
2004, 23, 1174. (b) Paneque, M.; Posadas, C. M.; Poveda, M. L.; Rendo´n,
´
N.; Santos, L. L.; Alvarez, E.; Salazar, V.; Mereiter, K.; On˜ate, E.
Organometallics 2007, 26, 3403. (c) Jacob, V.; Weakley, T. J. R.; Haley,
´
M. M. Angew. Chem., Int. Ed. 2002, 41, 3470. (d) Alvarez, E.; Paneque,
M.; Poveda, M. L.; Rendon, N. Angew. Chem., Int. Ed. 2006, 45, 474. (e)
Zhang, H.; Xia, H. P.; He, G. M.; Wen, T. B.; Gong, L.; Jia, G. Angew.
Chem., Int. Ed. 2006, 45, 2920. (f) Zhang, H.; Feng, L.; Gong, L.; Wu, L.;
He, G.; Wen, T. B.; Yang, F.; Xia, H. Organometallics 2007, 26, 2705. (g)
Gilbertson, R. D.; Lau, T. L. S.; Lanza, S.; Wu, H.-P.; Weakley, T. J. R.;
Haley, M. M. Organometallics 2003, 22, 3279.
As an offshoot of our continuing interest in constructing stable
metallacycles from C5 units, we now set out to investigate this
type of reaction using HCt CCH(OH)CHdCH26 as the starting
material, expecting that the relatively lower unsaturation of the
building block might lead to different chemistry. To this end,
we have studied the reaction of HCt CCH(OH)CHdCH2 with
OsCl2(PPh3)3,7 a readily accessible starting material for the
syntheses of osmium complexes.8 As expected, we have suc-
cessfully isolated and characterized some interesting stable
(4) Some examples of metallafurans: (a) Grotjahn, D. B.; Hoerter, J. M.;
Hubbard, J. L. J. Am. Chem. Soc. 2004, 126, 8866. (b) Dirnberger, T.;
Werner, H. Organometallics 2005, 24, 5127. (c) Bleeke, J. R. Organome-
tallics 2005, 24, 5190. (d) Li, X.; Chen, P.; Faller, J. W.; Crabtree, R. H.
Organometallics 2005, 24, 4810.
(5) Some recent work on other conjugated metallacycles: (a) Wang, Q.;
Fan, H.; Xi, Z. Organometallics 2007, 26, 775. (b) Chanda, N.; Sharp, P. R.
Organometallics 2007, 26, 3368. (c) Anderson, D. J.; McDonald, R.; Cowie,
M. Angew. Chem., Int. Ed. 2007, 46, 3741. (d) Gong, L.; Wu, L.; Lin, Y.;
Zhang, H.; Yang, F.; Wen, T.; Xia, H. Dalton Trans. 2007, 4122. (e)
Esteruelas, M. A.; Lo´pez, A. M.; Oliva´n, M. Coord. Chem. ReV. 2007, 251,
795. (f) Go´mez, M.; Paneque, M.; Poveda, M. L.; Alvarez, E. J. Am. Chem.
Soc. 2007, 129, 6093. (g) Purohit, C. S.; Verma, S. J. Am. Chem. Soc.
2007, 129, 3488.
(6) Czepa, A.; Hofmann, T. J. Agric. Food. Chem. 2004, 52, 4508.
(7) Jones, P. R.; Caulton, K. G. J. Am. Chem. Soc. 1975, 97, 4221.
10.1021/om8001558 CCC: $40.75
2008 American Chemical Society
Publication on Web 04/24/2008

Conjugated Osmacyclic Species
Organometallics, Vol. 27, No. 11, 2008 2585
Scheme 2
The single-crystal X-ray diffraction clearly revealed that
complex 3 contained an η2-allyl alcohol osmacycle. The bond
distances of Os1-C1 (2.075(4) Å), Os1-C4 (2.168(5) Å), and
Os1-C5 (2.135(4) Å) are within the range of typical Os-C
single bonds. The C1-C2 and C4-C5 bond distances (1.356(6)
and 1.342(8) Å, respectively) are typical for a CdC double
bond, while the C2-C3 (1.497(6) Å) and C3-C4 (1.510(7) Å)
bond distances are typical for a C-C single bond. The C3-
O1 bond length (1.417(5) Å) indicates the existence of a
hydroxyl group, which is close to that reported for the η2-allyl
alcohol complex C5Me5(CO)2Re(η2-HCt CCH2OH) (1.45(2)
Å).9
One-Pot Synthesis of Four Conjugated Osmacycles by
Heating Complex 2. During the process of our investigation
on the reactivity of 2, we found that heating a suspension of 2
in dichloromethane at 60 °C in a sealed tube led to the
unexpected formation of the different conjugated osmacyclic
species 4-7 in one pot (Scheme 2). After recrystallization of
the crude product from dichloromethane/ether, four kinds of
crystals with varied forms were collected and isolated manually.
Complex 4 could be isolated as dark green bulky crystals.
The structure established by X-ray diffraction (Figure 2)
indicates that 4 is a typical osmabenzene containing an
essentially planar six-membered metallacycle. The mean rms
(root mean square) deviation from the least-squares plane
through Os1/C1/C2/C3/C4/C5 is 0.0592 Å. Within the metal-
lacycle, the C-C bond distances are observed in the range
Figure 1. Molecular structure for the complex cation of 3. Selected
bond distances (Å) and angles (deg): Os1-C1 ) 2.075(4), Os1-C4
) 2.168(5), Os1-C5 ) 2.135(4), C1-C2 ) 1.356(6), C2-C3 )
1.497(6), C3-C4 ) 1.510(7), C4-C5 ) 1.342(8), O1-C3 )
1.417(5); C1-Os1-C5 ) 85.5(2), C2-C1-Os1 ) 118.9(3),
C1-C2-C3 ) 118.0(4), C2-C3-C4 ) 109.8(4), C3-C4-C5 )
114.0(5), C4-C5-Os1 ) 73.2(3), C3-C4-Os1 ) 114.0(3).
metallacycles and developed a convenient route to prepare four
different conjugated osmacyclic species (an osmabenzene, a
cyclic osmium η2-allene complex, an osmafuran, and an R,ꢀ-
unsaturated ketone complex) in a one-pot reaction.
Results and Discussion
Preparation of η2-Allyl Alcohol Osmacycles. Reaction of
HCt CCH(OH)CHdCH2with OsCl2(PPh3)3 (1) in THF at 0 °C
for 1 h yielded the yellow precipitate 2, which could be isolated
in 65% yield (Scheme 1). Complex 2 has poor solubility in
common organic solvents. It is only slightly soluble in CH2Cl2
and shows very low stability in solution, transforming almost
simultaneously during the dissolving process. As a result, neither
the solution NMR spectroscopic characterization data nor the
single-crystal X-ray diffraction data of 2 are available. However,
in view of our previous experience in the reaction of
HCt CCH(OH)CHt CH with OsCl2(PPh3)3, which led to the
formation of the complex OsCl2(PPh3)2(CHdC(PPh3)CH(OH)-
Ct CH) by nucleophilic attack of PPh3 on the coordinated
alkyne,2d we can infer that 2 is the η2-allyl alcohol osmacycle
OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CHdCH2) formed in a simi-
lar way. The solid-state NMR spectrum and elemental analysis
data of 2 are consistent with this conjecture. Especially, in the
solid-state 13C NMR spectrum, signals attributed to OsCH,
C(PPh3), and CH(OH) were observed at 207.9, 110.2, and 85.8
ppm, respectively, which are comparable with those of
OsCl2(PPh3)2(CHdC(PPh3)CH(OH)Ct CH) (δ 206.5, 111.2,
and 77.8 ppm).2d In addition, the two signals (δ 45.4 and 33.4
ppm) attributed to the carbons of the terminal coordinated double
bond are also close to those for reported η2-olefin complexes.2e
The structural formulation of 2 was further confirmed by the
synthesis of complex 3 from a simple ligand substitution reaction
of 2 with excess PMe3 (Scheme 1). Complex 3 showed better
solubility and higher stability than 2 and could be structurally
characterized. The crystal structure of 3 is shown in Figure 1.
Figure 2. Molecular structure of 4. Selected bond distances (Å)
and angles (deg): Os1-C1 ) 1.977(6), Os1-C5 ) 1.971(5),
C1-C2 ) 1.383(7), C2-C3 ) 1.412(8), C3-C4 ) 1.358(9),
C4-C5 ) 1.417(9); C1-Os1-C5 ) 89.4(2), C2-C1-Os1 )
128.0(4), C1-C2-C3 ) 124.5(6), C2-C3-C4 ) 123.6(5),
C3-C4-C5 ) 125.7(6), C4-C5-Os1 ) 126.8(5).
(8) (a) Balagurova, E. V.; Cheredilin, D. N.; Kolomnikova, G. D.; Tok,
O. L.; Dolgushin, F. M.; Yanovsky, A. I.; Chizhevsky, I. T. J. Am. Chem.
Soc. 2007, 129, 3745. (b) Zhang, L.; Dang, L.; Wen, T. B.; Sung, H. H.-
Y.; Williams, I. D.; Lin, Z.; Jia, G. Organometallics 2007, 26, 2849. (c)
Gauvin, R. M.; Rozenberg, H.; Shimon, L. J. W.; Ben-David, Y.; Milstein,
D. Chem. Eur. J. 2007, 13, 1382.

2586 Organometallics, Vol. 27, No. 11, 2008
Gong et al.
Scheme 3
Scheme 4
Figure 3. Molecular structure of 5. Selected bond distances (Å)
and angles (deg): Os1-C1 ) 2.014(8), Os1-C4 ) 2.205(10),
Os1-C5 ) 2.150(9), C1-C2 ) 1.382(9), C2-C3 ) 1.419(10),
C3-C4 ) 1.282(11), C4-C5 ) 1.390(12); C1-Os1-C5 )
108.2(3), C1-Os1-C4 ) 71.4(4), C5-Os1-C4 ) 37.2(3),
C2-C1-Os1 ) 122.0(6), C1-C2-C3 ) 113.8(7), C2-C3-C4
) 112.2(8), C3-C4-C5 ) 171.0(11), C4-C5-Os1 ) 73.6(6),
C3-C4-Os1 ) 119.8(7).
1.358(9)-1.417(9) Å, and the Os-C bond distances in the ring
are approximately equal (1.977(6) and 1.971(5) Å). The lack
of significant alternations in the C-C bond distances, together
with the planarity of the ring, indicates that the metallacycle
has a delocalized nature. The monophosphonium-substituted
osmabenzene 4 is structurally similar to our previous osma-
benzene [OsCl2(PPh3)2(CHC(PPh3)CHC(PPh3)CH)]OH, bearing
two phosphonium substituents.2d
The NMR spectroscopic data of 4 are consistent with its solid-
state structure. In particular, the 1H NMR spectrum showed the
two characteristic OsCH signals at 20.6 and 18.9 ppm. The
proton opposite to the phosphonium group is more downfield
compared with that at the ortho position. The OsCH signals for
our previously reported iodoosmabenzene OsI2(PPh3)2(CHC-
(PPh3)CHC(I)CH) appeared at 20.1 and 19.0 ppm.2d The two
proton signals on C3 and C4 can be observed at 6.6 and 6.9
ppm, which are close to those of organic aromatic rings. The
facts also suggest that the metallacycle of 4 is delocalized.
A plausible mechanism for the formation of 4 is proposed as
shown in Scheme 3. The process may involve that dissociation
of OH- from 2 gives intermediate A followed by deprotonation
of the R-H to form osmabenzene 4. In addition, we found that
addition of NaHCO3 to the heating system would increase the
yield of 4(Scheme 4), which indicates deprotonation of the R-H
are more facile in the presence of base.
Although osmabenzenes act as the pioneer of metall-
abenzenes,2a the preparation routes of osmabenzenes are lim-
ited.2 The reactions described above provide new available
routes to prepare osmabenzene, which represent an extension
of our previously reported method to synthesize metallabenzenes
via the ring closure reactions.2d,3e,f
Complex 5 was isolated as light green prismatic crystals. The
structure of 5 (Figure 3) contains a conjugated osmacycle with
a terminal double bond of an allene coordinated to the metal
atom, which can also be viewed as a five-membered metalla-
cycle with an exocyclic methylene group coordinated to the
osmium center. The terminal coordinated double bond C4dC5
is almost coplanar with the osmacycle consisting of Os1, C1,
C2, C3, and C4. The coplanarity is reflected by the small
deviation (0.0537 Å) from the rms planes of the best fit through
the six atoms. The allene unit deviates slightly from linearity
with an C3-C4-C5 angle of 171.0°.
The solid-state structure of 5 is also fully supported by the
solution NMR spectroscopic data and elemental analysis. In
1
particular, the H NMR spectrum showed the OsCH signal at
12.0 ppm and the signals attributed to CHCCH2 and CHCCH2
at 7.6 and 2.7 ppm. The 31P{1H} NMR spectrum showed only
two singlets at 5.8 (CPPh3) and -11.0 ppm (OsPPh3), which
suggested a symmetric structure. In the 13C{1H} NMR spectrum,
the signals of OsCH and CPPh3 appeared at 208.7 and 113.0
ppm, while the three carbon signals of the coordinated allene
backbone appeared at 191.1 (CHCCH2), 114.0 (CHCCH2), and
24.8 (CHCCH2) ppm, respectively.
In contrast to the formation of 4, the intermediate A shown
in Scheme 3 can also tautomerize to B and then undergo
deprotonation of the ꢀ-H to generate the osmium allene complex
5. It is well-known that acid can promote the dissociation of
OH-. Consistent with this mechanism, treatment of 2 with acetic
acid in refluxing dichloromethane led to the formation of 5 in
76% yield. To further optimize the reaction conditions, we also
isolated 5 in 85% yield when utilizing acetic anhydride instead
of acetic acid (Scheme 4).
It is now well established that allenes are useful building
blocks in synthetic transformations to construct a variety of
compounds.10 Various stable coordinated allene complexes
containing different metals and structures have been isolated.11–13
However, as interesting species of these, osmium allene
complexes12,13a and cyclic metal allene complexes13 have been
limited to a few scattered reports. Complex 5 is a rare example
of a cyclic osmium η2-allene complex, which may be compared
with the allenylcarbene complexes OsCl2(dCPh-η2-CHdCd
(9) Casey, C. P.; Selmeczy, A. D.; Nash, J. R.; Yi, C. S.; Powell, D. R.;
Hayashi, R. K. J. Am. Chem. Soc. 1996, 118, 6698.
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Chem. Soc. 2007, 129, 14148. (e) Yoshino, T.; Ng, F.; Danishefsky, S. J.
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Res. 2003, 36, 701.

Conjugated Osmacyclic Species
Organometallics, Vol. 27, No. 11, 2008 2587
Scheme 5
temperature for about 30 h (Scheme 5). To the best of our
knowledge, 6 could be viewed as the first phosphonium salt of
metallafuran.
Another product, 7, was isolated as red prismatic crystals in
5% yield. Complex 7 was identified to be the R,ꢀ-unsaturated
ketone complex OsCl2(PPh3)2(CHdC(PPh3)C(O)CHdCH2),
which has been reported previously by us.2e Formally, complex
7 was formed via elimination of H2 from 2 in the reaction. The
introduction of oxygen into the system could improve the yield
of 7.
According to our initial design, the introduction of phospho-
niums to the metallacycles indeed improved the stability of these
complexes to some extent. In the solid state, all four of the
conjugated osmacycles are air-stable. Remarkably, the powders
of allene complex 5 and osmafuran 6 remained almost un-
changed when they were heated at 80 °C in air for several hours,
and the R,ꢀ-unsaturated ketone complex 7 remained stable even
when heated at 200 °C in air for 5 h.
Figure 4. Molecular structure of 6. Selected bond distances (Å)
and angles (deg): Os1-C1 ) 1.904(10), Os1-O1 ) 2.124(7),
C1-C2 ) 1.395(15), C2-C3 ) 1.404(15), C3-O1 ) 1.262(12),
C3-C4 ) 1.499(15), C4-C5 ) 1.480(18); C1-Os1-O1 )
78.5(4), C2-C1-Os1 ) 116.5(7), C3-O1-Os1 ) 113.2(6),
C1-C2-C3 ) 114.7(9), C2-C3-C4 ) 126.9(10), C3-C4-C5
) 112.8(11), C2-C3-O1 ) 116.4(9).
CH(Ph)(PPh3)213a and [CpRu(dC(Rc)-η2-CHdCdCH(Rc)(PP-
h3)]PF6.13b,c In sharp contrast to 5 which has a larger conjugated
planar metallacycle with the terminal double bond of allene
coordinated to osmium, the allenylcarbene complexes contain
bent four-membered metallacycles with internal double bonds
of allene coordinated to the metals. It is worth noting that
complex 5 shows remarkable air stability; even a solution of 5
can remain unchanged for over 1 month.
Conclusion
We have found an efficient one-pot method to prepare four
various conjugated osmacycles, which could also be prepared
in higher yield under the appropriate reaction conditions. This
new method allowed us to obtain interesting stable complexes
containing phosphoniums in the metallacyclic rings.
Complex 6 was collected as brownish bulky crystals and
identified to be a 2-osmafuran, which has been established by
the solution NMR spectroscopic data as well as the solid-state
structure (Figure 4). A possible mechanism for the generation
of 6 may include multiple hydrogen migration steps. Formally,
the alcohol is dehydrogenated, accompanied by hydrogenation
of the terminal alkene in the transformation of 2 to 6, which
can be regarded as an intramolecular version of transfer
hydrogenation.14 Additionally, 6 could be isolated in higher yield
(88%) when the suspension of 2 in CH2Cl2 was stirred at room
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 distilled
under nitrogen from sodium benzophenone (ether, tetrahydrofuran)
or calcium hydride (dichloromethane). The starting materials
HCt CCH(OH)CHdCH2 and OsCl2(PPh3)3 were synthesized by
literature procedures. Column chromatography was performed on
neutral alumina gel (200-300 mesh). All of 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
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Schottenberger, H.; Calhorda, M. J.; Veiros, L. F. Chem. Eur. J. 2002, 8,
3948.
(14) (a) Ouellet, S. G.; Walji, A. M.; Macmillan, D. W. C. Acc. Chem.
Res. 2007, 40, 1327. (b) Quan, M.; Sanchez, D.; Wasylkiw, M. F.; Smith,
D. K. J. Am. Chem. Soc. 2007, 129, 12847. (c) Ikariya, T.; Blacker, A. J.
Acc. Chem. Res. 2007, 40, 1300.
1
MHz; 31P, 162.0 MHz) spectrometer. H and 13C NMR chemical
shifts are relative to TMS, and 31P NMR chemical shifts are relative
to 85% H3PO4. Elemental analysis data were obtained on a Thermo
Quest Italia SPA EA 1110 instrument.
OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CHdCH2) (2). A mixture
of OsCl2(PPh3)3 (1.00 g, 0.96 mmol) and HCt CCH(OH)CHdCH2
(86.1 mg, 1.05 mmol) in THF (4 mL) was stirred at 0 °C for 1 h
to give a brown-yellow suspension. The yellow solid was collected
by filtration, washed with CH2Cl2 (2 × 2 mL), and then dried under
vacuum (0.70 g, 65%). The solid-state NMR experiment was
performed on a Bruker AV300 spectrometer operating at a MAS
frequency of 11 KHz using a Bruker 4 mm probe. Solid-state 31P
NMR (121.5 MHz): δ 7.3 (CPPh3), -7.1 ppm (OsPPh3). Solid-
state 13C NMR (75.5 MHz): δ 207.9 (OsCH), 110.2 (C(PPh3)),
85.8 (CH(OH)), 45.4 (CHCH2), 33.4 ppm (CHCH2). Anal. Calcd
for C59H51OP3Cl2Os: C, 62.71; H, 4.55; Found: C, 62.32; H, 4.65.
[OsCl(PMe3)3(CHdC(PPh3)CH(OH)CHdCH2)]Cl (3). A so-
lution of PMe3 in THF (1.0 M, 3.0 mL, 3.0 mmol) was added to a
suspension of OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CHdCH2) (2;
0.34 g, 0.30 mmol) in CH2Cl2 (10 mL). The mixture was stirred at
room temperature for about 12 h to give a light yellow solution.

2588 Organometallics, Vol. 27, No. 11, 2008
Gong et al.
Table 1. Crystal Data and Structure Refinement Details for 3-6
3
4
5
6
empirical formula
formula wt
temp, K
C33H50Cl4OsOP4
918.61
173(2)
C59H49Cl2OsP3
1111.99
223(2)
C59H49Cl2OsP3
1111.99
223(2)
C59.75H52.50Cl3.5OsO1.50P3
1201.70
223(2)
radiation (Mo KR), Å
0.710 73
triclinic
P1
0.710 73
monoclinic
P21/c
11.8066(7)
23.73951(15)
17.4227(4)
90
90.885(4)
90
4882.7(4)
4
0.710 73
monoclinic
P21/c
12.4030(5)
18.5440(8)
21.4896(8)
90
102.065(4)
90
4833.5(3)
4
0.710 73
triclinic
P1
cryst syst
j
j
space group
a, Å
b, Å
11.1653(4)
12.7631(3)
13.6141(4)
87.747(2)
85.366(2)
83.153(2)
1919.07(10)
2
12.249(2)
12.959(2)
20.138(3)
98.431(3)
95.354(3)
113.906(3)
2849.3(8)
2
c, Å
R, deg
ꢀ, deg
γ, deg
V, Å3
Z
dcalcd, g cm-3
abs coeff, mm-1
F(000)
1.590
3.793
920
1.513
2.859
2232
1.528
2.888
2232
1.401
2.525
1207
cryst size, mm
no. of rflns collected
no. of indep rflns
0.28 × 0.25 × 0.20
0.28 × 0.24 × 0.20
0.29 × 0.16 × 0.08
0.35 × 0.24 × 0.20
14 019
48 489
21 519
20 698
6592
8484
8433
9932
no. of obsd rflns (I > 2σ(I)) 5597
7035
8484/6/586
1.031
4565
8433/25/586
1.061
9110
9932/54/658
1.039
no. of data/restraints/params 6592/18/388
goodness of fit on F2
final R (I > 2σ(I))
R indices (all data)
1.009
R1 ) 0.0280, wR2 ) 0.0677 R1 ) 0.0509, wR2 ) 0.0804 R1 ) 0.0493, wR2 ) 0.0796 R1 ) 0.0797, wR2 ) 0.2203
R1 ) 0.0353, wR2 ) 0.696 R1 ) 0.0663, wR2 ) 0.0876 R1 ) 0.1011, wR2 ) 0.0861 R1 ) 0.0859, wR2 ) 0.2262
The volume of the solution was reduced to approximately 1 mL
under vacuum. Addition of diethyl ether (10 mL) to the solution
gave a white precipitate, which was collected by filtration, and
subsequent recrystallization of the crude product from dichlo-
0.35 mmol) and AcOH (0.057 mL, 1.0 mmol) in dichloromethane
(10 mL) was stirred at reflux for ca. 1 h to give a green solution.
The solvent was evaporated to dryness under vacuum, and the
resulting residue was washed with ether (5 × 3 mL) and then dried
under vacuum. Yield: 0.30 g, 76%.
Method D. OsCl2(PPh3)2(CHdC(PPh3)CHdCdCH2) (5). A
mixture of OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CH)CH2) (2) (0.40
g, 0.35 mmol) and Ac2O (0.16 mL, 1.7 mmol) in dichloromethane
(10 mL) was stirred at reflux for ca. 1 h to give a green solution.
The solvent was evaporated to dryness under vacuum, and the
resulting residue was washed with ether (5 × 3 mL) and then dried
under vacuum. Yield: 0.33 g, 85%. 1H NMR (400.1 MHz, CDCl3):
δ12.0 (d, 3J(PH) ) 16.0 Hz, 1H, OsCH), 7.6 (d, 3J(PH) ) 6.8 Hz,
1H, OsCHC(PPh3)CH, obscured by the phenyl signals and con-
1
romethane/hexane yielded white crystals. Yield: 0.22 g, 88%. H
NMR (300.1 MHz, CD2Cl2): δ 9.4 (d, 3J(PH) ) 25.5 Hz, 1H,
4
OsCH), 5.7 (d, J(PH) ) 4.5 Hz, 1H, OH), 5.4 (br, 1H, CHOH),
3.5 (m, 1H, CHCH2), 2.1 (m, 2H, CHCH2), 7.4-7.8 (m, 15H, PPh3),
1.1-1.9 ppm (m, 27H, PMe3). 31P{1H} NMR (121.5 MHz,
4
CD2Cl2): δ 13.6 (dt, J(PP) ) 28.2, 4.7 Hz, CPPh3), -46.7 (dd,
2J(PP) ) 21.6 Hz, 4J(PP) ) 4.7 Hz, OsPMe3), -55.6 ppm (dt,
2
4J(PP) ) 28.2 Hz, J(PP) ) 21.6 Hz, OsPMe3). Anal. Calcd for
C32H48OP4Cl2Os: C, 46.10; H, 5.80. Found: C, 46.07; H, 5.76.
Method A. One-Pot Reaction To Synthesize OsCl2(PPh3)2-
(CHC(PPh3)CHCHCH) (4), OsCl2(PPh3)2(CHdC(PPh3)CHd
CdCH2) (5), OsCl2(PPh3)2(CHC(PPh3)C(CH2CH3)O) (6), and
OsCl2(PPh3)2(CHdC(PPh3)C(O)CHdCH2) (7). A suspension of
OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CHdCH2) (2; 0.40 g, 0.35
mmol) in dichloromethane (8 mL) was heated to 60 °C for 6 h in
a sealed tube. Then the reaction system was cooled to room
temperature and depressurized to atmospheric pressure. A green
solution was collected, concentrated to 3 mL under vacuum, and
then layered with diethyl ether (6 mL). Dark green bulky crystals
of 4 (0.11 g, 28%), light green prismatic crystals of 5 (0.16 g, 40%),
brownish bulky crystals of 6 (0.044 g, 11%), and red prismatic
crystals of 7 (0.020 g, 5%) were collected and isolated manually.
Method B. OsCl2(PPh3)2(CHC(PPh3)CHCHCH) (4). A mix-
ture of OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CHdCH2) (2; 0.40 g,
0.35 mmol) and NaHCO3 (30 mg, 0.36 mmol) in dichloromethane
(10 mL) was stirred at reflux for ca. 1 h to give a green solution,
which was concentrated to 3 mL under vacuum and then layered
with diethyl ether (8 mL). Dark green bulky crystals of 4 (0.17 g,
43%) and light green prismatic crystals of 5 (0.16 g, 40%) could
be collected and isolated manually. 1H NMR (300.1 MHz, CD2Cl2):
1
3
firmed by H-13C HMQC), 2.7 (t, J(PH) ) 6.0 Hz, 2H, CCH2),
6.9-7.8 ppm (m, 45H, PPh3). 31P{1H} NMR (162.0 MHz, CDCl3):
δ 5.8 (s, CPPh3), -11.0 ppm (s, OsPPh3). 13C{1H} NMR (75.5
3
MHz, CD2Cl2): δ 208.7 (br, OsCH), 191.1 (d, J(PC) ) 23.5 Hz,
CHCCH2), 114.0 (d, 2J(PC) ) 27.2 Hz, CHCCH2), 113.0 (d, 1J(PC)
) 76.3 Hz, C(PPh3)), 24.8 (s, CCH2), 120.0-134.0 ppm (m, PPh3).
Anal. Calcd for C59H49P3Cl2Os: C, 63.72; H, 4.44. Found: C, 63.57;
H, 4.80.
Method E. OsCl2(PPh3)2(CHC(PPh3)C(CH2CH3)O) (6). A
suspension of OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CHdCH2) (2;
0.40 g, 0.35 mmol) in dichloromethane (15 mL) was stirred at room
temperature for 30 h to give a brown solution. The volume of the
mixture was reduced to approximately 2 mL under vacuum.
Addition of diethyl ether (10 mL) to the solution gave a brownish
green precipitate, which was collected by filtration, and subsequent
recrystallization of the crude product from dichloromethane/ether
yielded green crystals. Yield: 0.35 g, 88%. 1H NMR (300.1 MHz,
CD2Cl2): δ 14.9 (d, 3J(PH) ) 12.0 Hz, 1H, OsCH), 2.2 (dq, 2J(HH)
3
2
) 15.0 Hz, J(HH) ) 7.2 Hz, 1H, CH2CH3), 1.8 (dq, J(HH) )
15.0 Hz, 3J(HH) ) 7.2 Hz, 1H, CH2CH3), 0.8 (dd, 2J(HH) ) 7.2,
7.2 Hz, 3H, CH2CH3), 6.9-7.8 ppm (m, 45H, PPh3). 31P{1H} NMR
3
3
δ 20.6 (dt, J(HH) ) 7.7 Hz, J(PH) ) 3.6 Hz, 1H, OsCHCH),
18.9 (dt, 3J(PH) ) 20.7 Hz, 3J(PH) ) 2.6 Hz, 1H, OsCHC(PPh3)),
2
3
3
(121.5 MHz, CD2Cl2): δ 15.1 (s, CPPh3), -2.9 (d, J(PP) ) 16.9
6.9 (dd, J(PH) ) 12.3 Hz, J(HH) ) 7.7 Hz, 1H, OsCHCHCH),
Hz, OsPPh3), -5.7 ppm (d, 2J(PP) ) 16.9 Hz, OsPPh3). 13C{1H}
3
6.6 (t, J(HH) ) 7.7 Hz, 1H, OsCHCH), 7.0-7.9 ppm (m, 45H,
NMR (100.6 MHz, CD2Cl2): δ 241.0 (br, OsCH), 205.8 (d, 2J(PC)
PPh3). 31P{1H} NMR (121.5 MHz, CD2Cl2): δ 18.0 (s, CPPh3),
-13.0 ppm (s, OsPPh3). Anal. Calcd for C59H49P3Cl2Os: C, 63.72;
H, 4.44. Found: C, 63.78; H, 4.70.
1
) 10.1 Hz, C(O)CH2CH3), 113.0 (d, J(PC) ) 88.6 Hz, CPPh3),
31.5 (s, CH2CH3), 10.1 (s, CH2CH3), 121.4-138.2 ppm (m, PPh3).
Anal. Calcd for C59H51OP3Cl2Os: C, 62.71; H, 4.55. Found: C,
62.40; H, 4.87.
Method C. OsCl2(PPh3)2(CHdC(PPh3)CHdCdCH2) (5). A
mixture of OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CHdCH2) (2; 0.40 g,

Conjugated Osmacyclic Species
Organometallics, Vol. 27, No. 11, 2008 2589
Method F. OsCl2(PPh3)2(CHdC(PPh3)C(O)CHdCH2) (7). A
suspension of OsCl2(PPh3)2(CHdC(PPh3)CH(OH)CHdCH2) (2;
0.40 g, 0.35 mmol) in dichloromethane (8 mL) was heated at 60
°C for 6 h under an air atmosphere in a sealed tube. Then the
reaction system was cooled to room temperature and depressurized
to atmospheric pressure. The volume of the mixture was reduced
to approximately 2 mL under vacuum. A red powder deposited,
which was collected by filtration, washed with chloroform (2 mL
× 2), and dried under vacuum. Yield: 0.11 g, 28%. 1H NMR
KR radiation (λ ) 0.710 73 Å). Multiscan or empirical absorption
corrections (SADABS) 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. All non-H atoms were refined
anisotropically. Hydrogen atoms were introduced at their geometric
positions and refined as riding atoms. CCDC 675408 (3), 671116
(4), 671118 (5), and 671117 (6) contain the supplementary
crystallographic data for this paper. Details on crystal data, data
collection, and refinements are summarized in Table 1.
3
(CDCl3, 300.1 MHz): δ 13.1 (d, J(PH) ) 15.0 Hz, 1 H, OsCH),
3.5 (m, 1 H, CHCH2), 3.1 (m, 1 H, CHCH2), 2.6 (m, 1 H, CHCH2),
6.8-7.9 (m, 45 H, PPh3). 31P{1H} NMR (CDCl3, 121.5 MHz): δ
2
Acknowledgment. This work was financially supported
by the program for New Century Excellent Talents in
University of China (No. NCET-04-0603) and the National
Science Foundation of China (No. 20572089).
7.6 (s, CPPh3), -2.4 (d, J(PP) ) 255.2 Hz, OsPPh3), -14.3 (d,
2J(PP) ) 255.2 Hz, OsPPh3). Anal. Calcd for C59H49OP3Cl2Os: C,
62.82; H, 4.38. Found: C, 62.84; H, 4.52.
X-ray Crystal Structure Determination of 3-6. Crystals
suitable for X-ray diffraction were grown from CH2Cl2 or CHCl3
solutions layered with ether or n-hexane for complexes 3-6.
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 or a
Bruker Apex CCD area detector using graphite-monochromated Mo
Supporting Information Available: CIF files giving X-ray
crystallographic data for 3-6. This material is available free of
charge via the Internet at http://pubs.acs.org.
OM8001558