Substituted cyclopentadienyl osmium complexes from the reactions of OsH3Cl(PPh3)3 with fulvenes and cyclopentadienes

Article abstract of DOI:10.1021/om1005066

Two methodologies were developed for the preparation of half-sandwich osmium complexes with the general formula (η⁵-cyclopentadienyl) OsCl(PPh₃)₂. The first approach involves the reactions of OsH₃Cl(PPh₃)₃ with cyclopentadienes. Treatment of OsH₃Cl(PPh₃)₃ with cyclopentadienes gives (η⁵-cyclopentadienyl)OsCl(PPh₃)₂ via C-H oxidative addition of cyclopentadienes followed by reductive elimination of hydrogen. The methodology has enabled us to synthesize a series of half-sandwich osmium complexes containing Cp, Cp*, indenyl, and C₅Me ₄R (R = H, Et, n-Pr). The second approach involves the insertion reactions of OsH₃Cl(PPh₃)₃ with fulvenes. Treatment of OsH₃Cl(PPh₃)₃ with C6-substituted fulvenes produces cleanly monosubstituted cyclopentadienyl osmium complexes (η⁵-C₅H₄CHRR′)OsCl(PPh ₃)₂ (R = H, R′ = p-C₆H₄CH ₃, p-C₆H₄OCH₃, CMe₃; R = R′ = Ph) via hydride transfer to the electrophilic exocyclic carbon of fulvenes. Under similar conditions, OsH₃Cl(PPh₃) ₃ reacts with C6-monosubstituted 1,2,3,4-tetramethylfulvenes to give pentasubstituted cyclopentadienyl osmium complexes (η⁵-C ₅Me₄CH₂R)OsCl(PPh₃)₂ (R = p-C₆H₄CH₃, p-C₆H ₄OCH₃, pyrenyl).

Full text of DOI:10.1021/om1005066

Organometallics 2010, 29, 3571–3581 3571
DOI: 10.1021/om1005066
Substituted Cyclopentadienyl Osmium Complexes from the Reactions of
OsH3Cl(PPh3)3 with Fulvenes and Cyclopentadienes
Sunny Kai San Tse, Wei Bai, Herman Ho-Yung Sung, Ian Duncan Williams, and
Guochen Jia*
Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay,
Kowloon, Hong Kong
Received May 24, 2010
Two methodologies were developed for the preparation of half-sandwich osmium complexes with
the general formula (η5-cyclopentadienyl)OsCl(PPh3)2. The first approach involves the reactions of
OsH3Cl(PPh3)3 with cyclopentadienes. Treatment of OsH3Cl(PPh3)3 with cyclopentadienes gives
(η5-cyclopentadienyl)OsCl(PPh3)2 via C-H oxidative addition of cyclopentadienes followed by
reductive elimination of hydrogen. The methodology has enabled us to synthesize a series of half-
sandwich osmium complexes containing Cp, Cp*, indenyl, and C5Me4R (R = H, Et, n-Pr). The
second approach involves the insertion reactions of OsH3Cl(PPh3)3 with fulvenes. Treatment of
OsH3Cl(PPh3)3 with C6-substituted fulvenes produces cleanly monosubstituted cyclopentadienyl
osmium complexes (η5-C5H4CHRR0)OsCl(PPh3)2 (R = H, R0 = p-C6H4CH3, p-C6H4OCH3, CMe3;
R=R0 =Ph) via hydride transfer to the electrophilic exocyclic carbon of fulvenes. Under similar
conditions, OsH3Cl(PPh3)3 reacts with C6-monosubstituted 1,2,3,4-tetramethylfulvenes to give
pentasubstituted cyclopentadienyl osmium complexes (η5-C5Me4CH2R)OsCl(PPh3)2 (R=p-C6H4-
CH3, p-C6H4OCH3, pyrenyl).
Introduction
activity and selectivity.2 In this regard, it is desirable to
prepare half-sandwich group 8 transition metal cyclopenta-
dienyl complexes with various substituents on the Cp ring.
In fact, a number of half-sandwich ruthenium com-
plexes of various substituted cyclopentadienyl ligands have
been synthesized in the past.3 In contrast, the chemistry of
Half-sandwich group 8 transition metal cyclopentadienyl
complexes play a key role in the development of organome-
tallic chemistry and homogeneous catalysis.1 It has been
demonstrated that replacement of one or more of the hydro-
gens of the cyclopentadienyl (C5H5) ring by other substitu-
ents can lead to significant changes in the reactivity and
catalytic properties of these complexes due to steric and
electronic effects induced by these substituents. For example,
Cp*RuCl(PPh3)2 can efficiently mediate the coupling reac-
tions of azides with terminal alkynes to give selectively 1,5-
disubstituted 1,2,3-triazoles, whereas the analogous complex
CpRuCl(PPh3)2 is much less effective in terms of both
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ust.hk.
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2010 American Chemical Society
Published on Web 07/15/2010
pubs.acs.org/Organometallics

3572 Organometallics, Vol. 29, No. 16, 2010
Tse et al.
half-sandwich osmium complexes with a substituted cyclo-
pentadienyl ligand, with the exception of Cp*Os complexes,4
is still underdeveloped, despite the considerable interest in
the chemistry of half-sandwich CpOs complexes.5 Until now,
a very limited number of half-sandwich osmium complexes
with a substituted cyclopentadienyl ligand other than Cp*
and indenyl are known. Notable examples of these com-
plexes include those with C5Ar5,6 iPr4C5H,7 and C5H4R8-10
groups.
This work concerns syntheses of half-sandwich osmium
cyclopentadienyl complexes of the type (η5-cyclopentadienyl)-
OsCl(PPh3)2. Osmium halo complexes (η5-cyclopentadienyl)-
OsX(PR3)2 are very useful precursors for organometallic syn-
thesis. For example, CpOsBr(PPh3)2 is one of the commonly
used starting materials to make other half-sandwich CpOs
complexes;11 CpOsCl(PiPr3)2 is another versatile starting ma-
terial that has also been used to make over 200 new compounds
and for the development of interesting organometallic chemistry
of osmium.5e,f,12
(4) Examples of recent work: (a) Hayes, P. G.; Gribble, C. W.;
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2007, 26, 2258. (d) Gross, C. L.; Girolami, G. S. Organometallics 2007, 26,
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J. Am. Chem. Soc. 2000, 122, 972.
Previously reported osmium halo complexes (η5-cyclo-
pentadienyl)OsX(PR3)2 are mainly those containing Cp,
Cp*, and indenyl ligands. Several approaches have been
used to synthesize such complexes depending on the ligands.
The cyclopentadienyl complex CpOsBr(PPh3)2 could be
synthesized by refluxing a mixture of H2OsBr6/PPh3/CpH
in alcohols.13-15 CpOsX(PPh3)2 (X = Cl, Br) and CpOsCl-
(PiPr3)2 have been prepared by the metathesis reactions of
cyclopentadienyl anion (e.g., LiCp, TlCp) with haloosmium
(5) Examples of recent work: (a) Castro-Rodrigo, R.; Esteruelas,
ꢀ
ꢀ
~
M. A.; Fuertes, S.; Lopez, A. M.; Lopez, F.; Mascarenas, J. L.; Mozo, S.;
~
Onate, E.; Saya, L.; Villarino, L. J. Am. Chem. Soc. 2009, 131, 15572. (b)
ꢀ
Castro-Rodrigo, R.; Esteruelas, M. A.; Fuertes, S.; Lopez, A. M.; Mozo, S.;
16
complexes OsX2(PPh3)3 and OsH2Cl2(PiPr3)2,17 respec-
~
ꢀ
Onate, E. Organometallics 2009, 28, 5941. (c) Esteruelas, M. A.; Hernandez,
ꢀ
ꢀ
Y. A.; Lopez, A. M.; Olivan, M.; Rubio, L. Organometallics 2008, 27, 799.
tively. It was reported very recently that the complex
CpOsCl(PPh3)2 can be prepared directly from the reaction
of OsCl2(PPh3)3 with cyclopentadiene.18 Other half-sandwich
Cp complexes CpOsX(PR3)2 were usually obtained by ligand
substitution reactions of CpOsX(PPh3)2 (X=Cl, Br)19 and
CpOsCl(PiPr3)2.17 The Cp* complexes Cp*OsX(PR3)2 were
usually prepared from the reactions of PR3 with [Cp*OsBr2]2
or Cp*OsX(COD) (X=Br, Cl),4c,16,20,21 which were in turn
prepared from the reactions of H2OsBr6 with C5Me5H in
alcohols and reactions of K2[OsO2(OH)4]/HX with
C5Me5H/COD,16 respectively. The indenyl complexes (η5-
ꢀ
ꢀ
ꢀ
~
(d) Esteruelas, M. A.; Gonzalez, A. I.; Lopez, A. M.; Olivan, M.; Onate, E.
Organometallics 2006, 25, 693. (e) Esteruelas, M. A.; Hernandez, Y. A.;
Lopez, A. M.; Olivan, M.; Onate, E. Organometallics 2005, 24, 5989. (f )
Baya, M.; Buil, M. L.; Esteruelas, M. A.; Onate, E. Organometallics 2005,
24, 5180. (g) Bruce, M. I.; Costuas, K.; Ellis, B. G.; Halet, J. F.; Low, P. J.;
Moubaraki, B.; Murray, K. S.; Ouddaï, N.; Perkins, G. J.; Skelton, B. W.;
White, A. H. Organometallics 2007, 26, 3735. (h) Liu, C. W.; Lin, Y. C.;
Huang, S. L.; Cheng, C. W.; Liu, Y. H.; Wang, Y. Organometallics 2007, 26,
3431. (i) Bruce, M. I.; Low, P. J.; Hartl, F.; Humphrey, P. A.; Montigny, F.;
Jevric, M.; Lapinte, C.; Perkins, G. J.; Roberts, R. L.; Skelton, B. W.; White,
A. H. Organometallics 2005, 24, 5241. (j) Lutz, C. M.; Wilson, S. R.;
Shapley, P. A. Organometallics 2005, 24, 3350. (k) Carbo, J. J.; Crochet, P.;
Esteruelas, M. A.; Jean, Y.; Lledos, A.; Lopez, A. M.; Onate, E. Organome-
tallics 2002, 21, 305.
(6) (C5Ar5)OsBr(CO)2 (C5Ar5 = C5Ph5, C5Ph4(p-tBuC6H4, C5(p-
MeC6H4)5) were obtained by oxidative addition reactions of Os3(CO)12
with bromocyclopentadienes C5Ar5Br. Field, L. D.; Hambley, T. W.;
Humphrey, P. A.; Masters, A. F.; Turner, P. Polyhedron 1998, 17, 2587.
(7) (iPr4C5H)OsI(CO)2 was obtained by the reaction of tetraisopro-
pylcyclopentadiene with [(CO)3OsI2]2. Zhang, J.; Huang, K. W.; Szalda,
D. J.; Bullock, R. M. Organometallics 2006, 25, 2209.
ꢀ
ꢀ
ꢀ
~
~
ꢀ
ꢀ
ꢀ
~
C9H7)OsX(PPh3)2 (X = Cl, Br) have been synthesized by the
22,23
reactions of indenyllithium with OsX2(PPh3)3. Half-
sandwich indenyl complexes containing other phosphine
ꢀ
(12) Esteruelas, M. A.; Lopez, A. M. Organometallics 2005, 24, 3584,
and reference therein.
(8) A series of monosubstituted cyclopentadienyl osmium complexes
were synthesized starting from the reactions of [C5H4CH2CH2Y]Li
(Y = PPh2, OMe, NMe2) with OsH2Cl2(PiPr3)2. (a) Esteruelas,
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metallics 1997, 16, 4657.
ꢀ
~
M. A.; Lopez, A. M.; Onate, E.; Royo, E. Organometallics 2004, 23,
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~
5633. (b) Esteruelas, M. A.; Lopez, A. M.; Onate, E.; Royo, E. Organome-
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~
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tallics 2004, 23, 3021. (c) Esteruelas, M. A.; Lopez, A. M.; Onate, E.; Royo,
E. Inorg. Chem. 2005, 44, 4094.
(9) Several monosubstituted cyclopentadienyl osmium complexes
have been obtained from reactions of cyclopentadienyl osmium com-
plexes. For example, CpOsHCl(EPh3)(PiPr3) (E = Si, Ge) react with
LiCH2CN to give (η5-C5H4EPh3)OsH2(CH2CN)(PiPr3) and with LiR
(R = Me, Bu, NR2, PPh2) to give (η5-C5H4R)OsH2(EPh3)(PiPr3);
CpOsH(CtCPh)(SiPh3)(PiPr3) reacts with BuLi followed by MeOH
to give (η5-C5H4SiPh3)OsH(dCdCHPh)(PiPr3). (a) Baya, M.; Crochet,
(18) Caporali, M.; Di Vaira, M.; Peruzzini, M.; Seniori Costantini, S.;
Stoppioni, P.; Zanobini, F. Eur. J. Inorg. Chem. 2010, 152.
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(21) Dub, P. A.; Belkova, N. V.; Lyssenko, K. A.; Silantyev, G. A.;
Epstein, L. M.; Shubina, E. S.; Daran, J. C.; Poli, R. Organometallics
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P.; Esteruelas, M. A.; Onate, E. Organometallics 2001, 20, 240. (b) Baya,
~
M.; Esteruelas, M. A.; Onate, E. Organometallics 2001, 20, 4875.
(10) (η5-C5H4Et)OsH5 was reported recently. Kameo, H.; Shima, T.;
Nakajima, Y.; Suzuki, H. Organometallics 2009, 28, 2535.
(11) Examples of recent work: (a) Byrne, L. T.; Koutsantonis, G. A.;
Sanford, V.; Selegue, J. P.; Schauer, P. A.; Iyer, R. S. Organometallics
2010, 29, 1199. (b) Berven, B. M.; Koutsantonis, G. A.; Skelton, B. W.;
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(22) (a) Gimeno, J.; Gonzalez-Cueva, M.; Lastra, E.; Perez-Carreno,
E.; Garcıa-Granda, S. Inorg. Chim. Acta 2003, 347, 99. (b) Gamasa, M. P.;
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K. M. Polyhedron 2009, 28, 844. (f ) Packheiser, R.; Lohan, M.; Brauer, B.;
Justaud, F.; Lapinte, C.; Lang, H. J. Organomet. Chem. 2008, 693, 2898. (g)
(23) Examples of other osmium sandwich complexes prepared from
Packheiser, R.; Ecorchard, P.; R€ueffer, T.; Lohan, M.; Brauer, B.; Justaud, F.;
the reactions of indenyl lithium with osmium precursors. (a) (η5-C9H7)
€
ꢀ
~
Lapinte, C.; Lang, H. Organometallics 2008, 27, 3444. (h) Packheiser, R.;
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Article
Organometallics, Vol. 29, No. 16, 2010 3573
ligands have been obtained by ligand substitution reactions
of (η5-C9H7)OsX(PPh3)2..21a
Scheme 1
Until now very few osmium complexes (η5-cyclopen-
tadienyl)OsX(PR3)2 with a substituted cyclopentadienyl li-
gand other than Cp* and indenyl were known. As rare
examples, Esteruelas et al. reported the synthesis of OsCl-
(η5-C5H4CH2CH2PPh2)(PiPr3) from the reaction of CCl4
with OsH(η5-C5H4CH2CH2PPh2)(PiPr3),8 and we reported
the synthesis of aryl-substituted indenyl complexes (η5-
C9H6(Ar))OsCl(PPh3)2 from the reductions of carbyne com-
plexes OsCl3(tCCHdCAr2)(PPh3)2 with zinc.24
In this work, we report two general methods for the
preparation of half-sandwich osmium complexes of the type
(η5-cyclopentadienyl)OsCl(PPh3)2 based on the reactions of
the readily available complex OsH3Cl(PPh3)3 with fulvene
derivatives and cyclopentadienes. The methodologies have
enabled us to synthesize a series of half-sandwich osmium
complexes containing Cp, Cp*, indenyl, and various sub-
stituted cyclopentadienyls.
Scheme 2
Results and Discussion
Preparation of Cyclopentadienyl Complexes from the Re-
actions of OsH3Cl(PPh3)3 with Cyclopentadienes. It is known
that cyclopentadienes can react with hydride complexes to
give cyclopentadienyl complexes. For example, treatment
of Re(PPh3)2H7 with cyclopentadiene gives CpReH2-
(PPh3),25,26 and photolysis of ReH5(PMe2Ph)3 with cyclo-
pentadiene in hexane led to CpReH4(PMe2Ph) and CpReH2-
(PMe2Ph)2.27 The reactions presumably proceed through
oxidative addition of C-H of cyclopentadiene (C5H6) fol-
lowed by elimination of H2. These observations prompted us
to investigate the reactions of OsH3Cl(PPh3)3 with several
cyclopentadienes with the hope of obtaining (η5-cyclo-
pentadienyl)OsCl(PPh3)2.
In our initial experiments, we studied the reactions of
OsH3Cl(PPh3)3 with cyclopentadiene and indene. Treatment
of OsH3Cl(PPh3)3 with 3 equiv of freshly distilled cyclopen-
tadiene in toluene at 110 °C for 2 h affords CpOsCl(PPh3)2
(1), which can be isolated as a yellow, air-stable solid in 61%
yield by recystallization from diethyl ether and hexane
(Scheme 1). The reaction can also be carried out at room
temperature in THF, although it takes 2 days to complete the
reaction.
reaction of OsH3Cl(PPh3)3 with cyclopentadiene may also
afford CpOsH(PPh3)2. However, the hydride complex was
not detected in our experiments.
A plausible pathway for the formation of the osmium
cyclopentadienyl complex 1 from the reactions of OsH3Cl-
(PPh3)3 with cyclopentadiene is shown in Scheme 2. OsH3Cl-
(PPh3)3 can lose a molecule of hydrogen to give the
unsaturated 16-electron complex OsHCl(PPh3)3. A cyclo-
pentadiene molecule can then coordinate to the osmium
center to give (η4-C5H6)OsHCl(PPh3)2, which gives inter-
mediate A. Oxidative addition of a C-H bond in cyclopen-
tadiene would give intermediate B, which can undergo
reductive elimination of H2 to give the final product 1. The
mechanism is similar to that proposed by Jones et al. for the
reaction of Re(PPh3)2H7 with cyclopentadiene to give
CpReH2(PPh3).25 In the rhenium system, (η4-C5H6)Re-
(PPh3)2H3 has been identified as the key intermediate. We
have failed to identify the reaction intermediates in our case.
Similarly, treatment of OsH3Cl(PPh3)3 with 1.5 equiv of
indene affords osmium indenyl complex (C9H7)OsCl(PPh3)2
(2). Complexes 116 and 221b have been previously prepared
from the reactions of OsCl2(PPh3)3 with LiCp/cyclopenta-
diene and indenyllithium. Our work provided an alternative
route to the complexes.
Encouraged by the successful preparation of cyclopenta-
dienyl and indenyl osmium complexes 1 and 2, we sought to
extend the synthetic protocol to synthesize substituted cyclo-
pentadienyl complexes. Reaction of OsH3Cl(PPh3)3 with
pentamethylcyclopentadiene in a 1:1.5 molar ratio in reflux-
ing toluene leads to the formation of the complex Cp*OsCl-
(PPh3)2 (3) (Scheme 3). As monitored by 31P{1H} NMR
spectroscopy, the reaction is completed in ca. 4 h to give
Cp*OsCl(PPh3)2 as the only product. From the reaction
mixture, Cp*OsCl(PPh3)2 was isolated in 85% yield. To
the best of our knowledge, Cp*OsCl(PPh3)2 has not been
reported previously, although the analogous complexes
The reaction of the hydride complex OsHCl(CO)(PiPr3)2
with cyclopentadiene was known to give the cyclopentadie-
nyl complex OsH(η5-C5H5)(CO)(PiPr3) due to elimination of
HCl instead of H2.28 Reactions between C5R5H (R=H, Me)
and OsX2(CO)4 or [OsX2(CO)3]2 (X = Cl, Br, I) also give
(η5-C5R5)OsX(CO)2 with the elimination of HX.29 Thus
(24) He, G.; Zhu, J.; Hung, W. Y.; Wen, T. B.; Sung, H. H. Y.;
Williams, I. D.; Lin, Z.; Jia, G. Angew. Chem., Int. Ed. 2007, 46, 9065.
(25) (a) Baudry, D.; Ephritikhine, M. J. Chem. Soc., Chem. Commun.
1980, 249. (b) Baundry, D.; Ephritikhine, M.; Felkin, H. J. Organomet.
Chem. 1982, 224, 363.
(26) (a) Jones, W. D.; Maguire, J. A. Organometallics 1987, 6, 1301.
(b) Jones, W. D.; Maguire, J. A. Organometallics 1985, 4, 951. (c) Jones,
W. D.; Maguire, J. A. J. Am. Chem. Soc. 1985, 107, 4544.
(27) Green, M. A.; Huffman, J. C.; Caulton, K. G.; Rybak, W. K.;
Ziolkowski, J. J. J. Organomet. Chem. 1981, 218, C39.
ꢀ
ꢀ
(28) Esteruelas, M. A.; Gomez, A. V.; Lopez, A. M.; Oro, L. A.
Organometallics 1996, 15, 878.
(29) (a) Pourreau, D. B.; Geoffroy, G. L.; Rheingold, A. L.; Geib,
S. J. Organometallics 1986, 5, 1337. (b) Hoyano, J. K.; Graham, W. A. G. J.
Am. Chem. Soc. 1982, 104, 3722. (c) Hoyano, J. K.; May, C. J.; Graham,
W. A. G. Inorg. Chem. 1982, 21, 3095.

3574 Organometallics, Vol. 29, No. 16, 2010
Tse et al.
Scheme 3
first converting fulvenes to cyclopentadienyl anions via their
reactions with reducing agents such as sodium, calcium,32 or
nucleophiles such as lithium or Grignard reagents,33 LiAlH4
and LiBHEt3,34 followed by the reactions of cyclopentadie-
nyl anions with suitable precursors. Cyclopentadienyl com-
plexes could also be obtained from the insertion reactions of
fulvenes with metal alkyl or hydride complexes. For exam-
ple, complexes M(CH2Ph)4 (M = Zr, Hf) react with 6,60-
disubstituted fulvenes to give the insertion products (C5H4-
CMe2CH2Ph)M(CH2Ph)3,35 and Bu2ZrCl2 reacts with 6-aryl-
substituted fulvenes to give a bis(benzylic cyclopentadienyl)-
zirconium dichloride complex presumably through the inser-
tion reaction of a hydride intermediate generated in situ from
β-hydrogen elimination.36 We have recently demonstrated that
monosubstituted cyclopentadienyl ruthenium complexes (η5-
C5H4CH2R)RuCl(PPh3)2 can be readily prepared from the
reaction between RuHCl(PPh3)3 and fulvenes.3c
In light of the success of the preparation of cyclopenta-
dienyl complexes via insertion reactions of fulvene deriva-
tives with metal hydride or alkyl complexes, we envisioned
that a variety of osmium cyclopentadienyl complexes (η5-
cyclopentadienyl)OsCl(PPh3)2 may be prepared from the
reactions of fulvenes with the osmium hydride complex
OsH3Cl(PPh3)3.
To explore the possibility, the reactions between C6-
substituted fulvenes 7S-10S and the osmium hydride com-
plex OsH3Cl(PPh3)3 were investigated (Scheme 4). At room
temperature, the reaction between OsH3Cl(PPh3)3 and ful-
vene 7S (in 1.5:1 molar ratio) in dichloromethane proceeded
to give complex (η5-C5H4CH2tolyl)OsCl(PPh3)2 (7) cleanly.
However the reaction occurred slowly and was completed in
72 h. When the reaction was carried out in THF at 80 °C, the
reaction was completed in 4 h, as monitored by 31P{1H}
NMR spectroscopy. The completion of the reaction is also
indicated by the change in the color of the reaction mixture
from initial orange to pale orange. The desired cyclopenta-
dienyl complex 7 can be isolated as an air-stable yellow
solid by column chromatography on aluminum oxide using
n-hexane followed by 5:1 n-hexane/diethyl ether as the
eluents. Under similar conditions, fulvenes 8S-10S reacted
with OsH3Cl(PPh3)3 to give the corresponding monosubsti-
tuted cyclopentadienyl osmium complexes 8-10, which can
be isolated in moderate to high yields.
All these complexes have been characterized by NMR and
elemental analysis. As expected, the 31P{1H} spectra of the
complexes show a singlet at ca. -2.0 ppm for the two
equivalent PPh3 ligands. The 1H NMR spectra display two
singlet signals at ca. 3.95 and 3.65 ppm for the protons of the
cyclopentadienyl ligands. The structures of complexes (η5-
C5H4CH2C6H4OMe)OsCl(PPh3)2 (8) and (η5-C5H4CH2tBu)-
OsCl(PPh3)2 (10) have been confirmed by X-ray diffraction. As
shown in Figures 4 and 5, both osmium complexes adopt a
30
19c
Cp*RuCl(PPh3)2
known for a long time.
and Cp*OsBr(PPh3)2
have been
Under similar conditions, reactions between OsH3Cl-
(PPh3)3 and other tetramethyl-substituted cyclopentadienes
(C5Me4R, R = H, Et, n-Pr) give the corresponding (η5-
C5Me4R)OsCl(PPh3)2 (R = H (4), Et (5), n-Pr (6)) in mode-
rate to high yields.
The new substituted tetramethylcyclopentadienyl com-
plexes (η5-C5Me4R)OsCl(PPh3)2 (R=Me (3), H (4), Et (5),
n-Pr (6)) are characterized by multinuclear NMR and elemen-
tal analysis. In the 31P{1H} NMR spectra, these complexes
show a sharp singlet for the two equivalent phosphine ligands in
the region of -2.5 to -3.5 ppm. In the 1H NMR spectrum of 3,
the Cp* ring shows a singlet at 1.3 ppm for the methyl groups.
Complexes 4-6 display a characteristic set of two singlets at ca.
1.4 and 1.3 ppm for the two distinguishable methyl groups of
the cyclopentadienyl ring.
The structures of complexes (C5Me5)OsCl(PPh3)2 (3,Figure1),
(η5-C5Me4H)OsCl(PPh3)2 (4, Figure 2), and (η5-C5Me4Pr)OsCl-
(PPh3)2 (6, Figure 3) have been confirmed by X-ray diffraction
studies. In all cases, the complexes adopt a piano stool structure
with PPh3 and Cl ligands as the legs. To prevent steric inter-
action between PPh3 and the substituent on the cyclopenta-
dienyl ligand, the Cl ligand is situated under the n-propyl
substituent in the (η5-C5Me4Pr)OsCl(PPh3)2 complex. In the
case of (η5-C5Me4H)OsCl(PPh3)2, the Cl ligand is situated
under the methyl group of the cyclopentadienyl ligand, while
the PPh3 is located under the C-H substituent. The average
˚
Os-C bond distances (2.247-2.250 A) between the cyclo-
pentadienyl carbons and the osmium center in these com-
plexes are similar and are slightly longer than the one in
CpOsCl(PPh3)2 (2.214 A).16 The bond lengths of Os-Cl and
˚
Os-P agree with those of CpOsCl(PPh3)2.
Preparation of Monosubstituted Cyclopentadienyl Com-
plexes from the Reactions of Monosubstituted Fulvenes with
OsH3Cl(PPh3)3. Substituted fulvenes are more easily acces-
sible and handled than cyclopentadiene derivatives. There-
fore they are attractive starting materials for the preparation
of cyclopentadienyl complexes.31 In fact, a number of cyclo-
pentadienyl complexes have been obtained from fulvenes by
(33) Suzuka, T.; Ogasawara, M.; Hayashi, T. J. Org. Chem. 2002, 67,
3355.
(34) Use of LiAlH4: (a) Plazuk, D.; Le Bideau, F.; Perez-Luna, A.;
Stephan, E.; Vessieres, A.; Zakrzewski, J.; Jaouen, G. Appl. Organomet.
Chem. 2006, 20, 168. (b) Hopf, H.; Sankararaman, S.; Dix, I.; Jones, P. G.;
Alt, H. G.; Licht, A. Eur. J. Inorg. Chem. 2002, 1, 123. Use of LiBHEt3: (c)
(30) Oshima, N.; Suzuki, H.; Moro-oka, Y.; Nagashima, H.; Ito, K.
J. Organomet. Chem. 1986, 314, C46.
(31) (a) Erker, G.; Kehr, G.; Frohlich, R. Organometallics 2008, 27, 3.
€
(b) Strohfeldt, K.; Tacke, M. Chem. Soc. Rev. 2008, 37, 1174. (c) Coville,
N. J.; Plooy, K. E.; Pickl, W. Coord. Chem. Rev. 1992, 116, 1.
€
ꢀ
(32) Use of Na, see for example: (a) Fischer, M.; Bonzli, P.; Stofer, B.;
Claffey, J.; Hogan, M.; M€uller-Bunz, H.; Pampillon, C.; Tacke, M.
Neuenschwander, M. Helv. Chim. Acta 1999, 82, 1509. Use of Ca, see for
example: (b) Kane, K. M.; Shapiro, P. J.; Vij, A.; Cubbon, R.; Rheingold,
A. L. Organometallics 1997, 16, 4567. (c) Sinnema, P. J.; Hohn, B.;
Hubbard, R. L.; Shapiro, P. J.; Twamley, B.; Blumenfeld, A.; Vij, A.
Organometallics 2002, 21, 182. (d) Eisch, J. J.; Shi, X.; Owuor, F. A.
Organometallics 1998, 17, 5219.
J. Organomet. Chem. 2008, 693, 526. (d) Strohfeldt, K.; M€uller-Bunz, H.;
ꢀ
Pampillon, C.; Sweeney, N. J.; Tacke, M. Eur. J. Inorg. Chem. 2006, 22,
4621.
(35) Rogers, J. S.; Lachicotte, R. J.; Bazan, G. C. Organometallics
1999, 18, 3976.
(36) Eisch, J. J.; Owuor, F. A.; Shi, X. Organometallics 1999, 18, 1583.

Article
Organometallics, Vol. 29, No. 16, 2010 3575
Figure 1. ORTEP drawing of Cp*OsCl(PPh3)2 (3). Thermal ellipsoids are shown at the 35% probability level. Selected bond lengths
˚
(A) and angles (deg): average Os-C (C5Me5), 2.247; Os-P(1), 2.3243(7); Os-P(2), 2.3132(7); Os-Cl(1), 2.4544(6); P(1)-Os(1)-Cl(1),
93.24(2); P(2)-Os(1)-P(1), 96.51(2).
Figure 2. ORTEP drawing of (η5-C5Me4H)OsCl(PPh3)2 (4). Thermal ellipsoids are shown at the 35% probability level. Selected bond
˚
lengths (A) and angles (deg): average Os-C (C5Me4H), 2.252; Os-P(1), 2.3274(13); Os-P(2), 2.3174(12); Os-Cl(1), 2.4430(13);
P(1)-Os(1)-Cl(1), 93.72(4); P(2)-Os(1)-P(1), 96.86(4).
three-legged piano stool structure with the Cl ligand located
under the pendent group for steric reasons. The pendent group
bends away from the metal center.
In our previous work, we found that reactions between
RuHCl(PPh3)3 and fulvenes having an sp3-CH proton at the
carbon R to the exocyclic carbon give the expected cyclopen-
tadienyl complexes together with a small amount of vinyl-
cyclopentadienyl complexes due to dehydrogenation.3c A simi-
lar result was observed in the reactions of OsH3Cl(PPh3)3 with
fulvene 11S. Treatment of OsH3Cl(PPh3)3 with fulvene 11S

3576 Organometallics, Vol. 29, No. 16, 2010
Tse et al.
Figure 3. ORTEP drawing of (η5-C5Me4Pr)OsCl(PPh3)2 (6). Thermal ellipsoids are shown at the 35% probability level. Selected bond
˚
lengths (A) and angles (deg): average Os-C (C5Me4Pr), 2.248; Os-P(1), 2.3224(6); Os-P(2), 2.3234(5); Os-Cl(1), 2.4632(6);
P(1)-Os(1)-Cl(1), 87.94(2); P(2)-Os(1)-P(1), 97.76(2).
Scheme 4
in THF at 80 °C for 4 h gives the cyclopentadienyl product 11A
and the vinyl-cyclopentadienyl product 11B in a molar ratio
of 4:1 (eq 1), as determined by the integrals of proton signals of
the Cp ring in the 1H NMR spectrum.
Preparation of Pentasubstituted Cyclopentadienyl Com-
plexes from the Reactions of Pentasubstituted Fulvenes with
OsH3Cl(PPh3)3. Having succeeded in the preparation of
monosubstituted cyclopentadienyl osmium complexes from
Polysubstituted fulvenes can be prepared by organic trans-
formation37 or by metal-catalyzed reactions.38 The desired
fulvene derivatives used in this work were prepared from the
reactions of 1,2,3,4-tetramethylcyclopentadiene with the corre-
fulvenes, we have tried to prepare substituted tetramethyl-
sponding aldehydes in methanol in the presence of excess
cyclopentadienyl osmium complexes via the reactions of
OsH3Cl(PPh3)3 with C6-substituted 1,2,3,4-tetramethylfulvenes.
KOtBu as the base, as shown in eq 2 in Scheme 5.
Thus, 6-tolyl-1,2,3,4-tetramethylfulvene (12S) was produced
from the condensation reaction between p-tolylaldehyde and
(37) (a) Krut’ko, D. P.; Borzov, M. V.; Dolomanov, O. V.; Churakov,
A. V.; Lemenovskii, D. A. Russ. Chem. Bull. 2005, 54, 390. (b) Krut'ko,
D. P.; Borzov, M. V.; Veksler, E. N. Russ. Chem. Bull. 2004, 53, 2182. (c)
(38) See for example: (a) Uemura, M.; Takayama, Y.; Sato, F. Org.
Lett. 2004, 6, 5001. (b) Kim, H. J.; Choi, N. S.; Lee, S. W. J. Organomet.
Chem. 2000, 616, 67. (c) Kotora, M.; Matsumura, H.; Gao, G.; Takahashi, T.
Org. Lett. 2001, 3, 3467, and references therein. (d) Radhakrishnan, U.;
Gevorgyan, V.; Yamamoto, Y. Tetrahedron Lett. 2000, 41, 1971.
€
Doring, S.; Erker, G. Synthesis 2001, 43. (d) Jutzi, P.; Heidemann, T.;
Neumann, B.; Stammler, H. G. Synthesis 1992, 1096. (e) Bensley, D. M.;
Mintz, E. A. J. Organomet. Chem. 1988, 353, 93. (f ) Pando, J. C.; Mintz,
E. A. Tetrahedron Lett. 1989, 4811.

Article
Organometallics, Vol. 29, No. 16, 2010 3577
tetramethylcyclopenta-1,3-diene in the presence of KOtBu.
The ligand was isolated as an orange oil by column chroma-
tography using basic Al2O3 as the solid phase and pentane as
the eluent. Following the same procedure, 6-anisolyl-1,2,3,4-
tetramethylfulvene (13S) and 6-pyrenyl-1,2,3,4-tetramethylful-
vene (14S) were prepared in high yield from the corresponding
aldehydes.
The identities of the new fulvenes were assigned on the
basis of NMR and MS spectroscopy. The solid-state struc-
ture of 14S has also been confirmed by X-ray diffraction
(Figure 6). The pyrene group of 14S is not perfectly coplanar
with the fulvene unit, but has a torsion angle of 13.68°. The
bond distances of C(1)-C(2), C(3)-C(4), and C(5)-C(10)
are slightly shorter than those of C(2)-C(3) and C(4)-C(5),
which confirms the structure of the fulvene system.
Having the new ligands in hand, we examined their reac-
tions with OsH3Cl(PPh3)3 for the synthesis of substituted
tetramethylcyclopentadienyl osmium complexes. Treatment
of ligand 12S with OsH3Cl(PPh3)3 in a molar ratio of 1.3:1 in
refluxing toluene resulted in the formation of (η5-C5Me4-
CH2tolyl)OsCl(PPh3)2 (12), which can be isolated in 75.9%
yield after purification by column chromatography. In a
similar fashion, (η5-C5Me4CH2anisolyl)OsCl(PPh3)2 (13)
Scheme 5
Figure 4. ORTEP drawing of (η5-C5H4CH2C6H4OMe)OsCl-
(PPh3)2 (8). Thermal ellipsoids are shown at the 40% probability
˚
level. Selected bond lengths (A) and angles (deg): average Os-C
(C5H4R), 2.209; Os-P(1), 2.320(2); Os-P(2), 2.308(2); Os-
Cl(1), 2.4582(19); P(1)-Os(1)-Cl(1), 91.39(7); P(2)-Os(1)-
P(1), 103.28(7).
Figure 5. ORTEP drawing of (η5-C5H4CH2CMe3)OsCl(PPh3)2 (10). Thermal ellipsoids are shown at the 35% probability level.
˚
Selected bond lengths (A) and angles (deg): average Os-C (C5H4R), 2.220; Os-P(1), 2.3088(15); Os-P(2), 2.3049(14); Os-Cl(1),
2.4565(15); P(1)-Os(1)-Cl(1), 94.56(5); P(2)-Os(1)-P(1), 99.16(5).

3578 Organometallics, Vol. 29, No. 16, 2010
Tse et al.
˚
Figure 6. ORTEP drawing of 14S. Thermal ellipsoids are shown at the 40% probability level. Selected bond lengths (A) and angles
(deg): C(1)-C(2), 1.339(2); C(2)-C(3), 1.482(2); C(3)-C(4), 1.345(2); C(4)-C(5), 1.491(2); C(5)-C(10), 1.342(2).
Scheme 6
and (η5-C5Me4CH2pyrenyl)OsCl(PPh3)2 (14) were obtained
from the reactions using S13 and S14, respectively.
All these complexes have been characterized by NMR and
elemental analysis. The 31P{1H} NMR spectra of complex
1
12-14 show a singlet at ca. -2 to -3 ppm. The H NMR
spectra display a set of three singlets at ca. 2.8, 1.2, and 1.1 ppm
with an intensity ratio of 1:3:3 for the CH2 and the methyl
groups. The solid-state structure of complex 12 (containing a
tolyl pendant group) has been determined by X-ray analysis.
Figure 7. ORTEP drawing of (η5-C5Me4CH2C6H4Me)OsCl
(PPh3)2 (12). Thermal ellipsoids are shown at the 35% prob-
˚
ability level. Selected bond lengths (A) and angles (deg): average
Os-C (C5Me4R), 2.243; Os-P(1), 2.3153(9); Os-P(2), 2.3317
(10); Os-Cl(1), 2.4727(10); P(1)-Os(1)-Cl(1), 87.14(3); P(2)-
Os(1)-P(1), 99.48(4).
Like the monosubstituted cyclopentadienyl complexes, the sub-
stituted tetramethylcyclopentadienyl complex 12 also adopts
a piano stool structure (Figure 7). The bond lengths and
bond angles are also similar to those of the cyclopentadienyl
complexes.
Conclusion
approach involves the reactions of OsH3Cl(PPh3)3 with
fulvenes. Treatment of OsH3Cl(PPh3)3 with C6-substitued
fulvenes gives monosubstituted cyclopentadienyl complexes.
6-Substituted-1,2,3,4-tetramethylfulvenes can be efficiently
synthesized by condensation reactions between 1,2,3,4-tetra-
methylcyclopentadiene and aldehydes in the presence of
KOtBu. The new fulvenes readily react with OsH3Cl(PPh3)3
to give complexes (η5-C5Me4CH2R)OsCl(PPh3)2.
In conclusion, we have developed two methodologies for
the preparation of half-sandwich osmium complexes with
the general formula (η5-cyclopentadienyl)OsCl(PPh3)2 using
OsH3Cl(PPh3)3 as the starting material. The first approach
involves the reactions of OsH3Cl(PPh3)3 with cyclopenta-
dienes. Thus, (η5-cyclopentadienyl)OsCl(PPh3)2 can be con-
veniently synthesized from the reactions of OsH3Cl(PPh3)3
with cyclopentadienes through C-H oxidative addition of
cyclopentadiene followed by reductive elimination of hydro-
gen. The methodology has enabled us to synthesize a series of
half-sandwich osmium complexes containing Cp, Cp*, in-
denyl, and several substituted cyclopentadienyls. The second
Experimental Section
All manipulations were carried out under a nitrogen atmo-
sphere using standard Schlenk techniques, unless otherwise
stated. Solvents were distilled under nitrogen from sodium

Article
Organometallics, Vol. 29, No. 16, 2010 3579
and benzophenone (n-hexane, diethyl ether), sodium (THF,
benzene), or calcium hydride (CH2Cl2). The starting materials
OsH3Cl(PPh3)3,39 S7/S8,40 S9,41 and S10/S1142 were prepared
following the procedures described in the literature. All other
reagents were used as purchased from Aldrich Chemical Co.
Microanalyses were performed by M-H-W Laboratories (Phoe-
13C{1H} NMR (75.5 MHz, CD2Cl2): δ 138.55 (d, J = 46.9 Hz),
134.94 (s), 128.47 (s), 126.66 (s) (PPh3), 90.01 (s), 87.65 (s), 83.84
(s) (C5Me4), 17.06 (s), 12.48 (s) (-Et), 8.86 (s), 8.60 (s) (C5Me4).
31P{1H} NMR (121.5 MHz, C6D6): δ -3.38 ppm (s). Anal.
Calcd for C47H47ClOsP2: C, 62.76; H, 5.27. Found: C, 62.87; H, 5.17.
(η5-C5Me4Pr)OsCl(PPh3)2 (6). OsH3Cl(PPh3)3 (506 mg, 0.50
mmol), C5Me4Hn-Pr (116 mg, 0.71 mmol, 1.4 equiv). Reaction
time: 8 h. Yield: 341 mg, 75.1%. 1H NMR (300 MHz, C6D6): δ
7.89 (br, 12H, PPh3), 7.04 (br, 18H, PPh3), 1.67 (t, J = 7.6 Hz,
2H, CH2CH2CH3); 1.44 (s, 6H, CH3 of C5Me4nPr); 1.37-1.34
(m, 8H, CH3 of C5Me4Pr and CH2CH2CH3), 0.87 (t, J = 7.2 Hz,
3H, CH2CH2CH3). 13C{1H} NMR (75.5 MHz, CD2Cl2): δ
138.73, (d, J = 47.3 Hz), 135.12 (s), 128.46 (s), 126.80 (s)
(PPh3), 90.03 (s), 87.29 (s), 85.15 (s) (C5Me4), 26.32 (s), 21.95
(s), 14.65 (s) (n-Pr), 9.05 (s) (C5Me4). 31P{1H} NMR (C6D6,
121.5 MHz): δ -3.46 ppm (s). Anal. Calcd for C48H49ClOsP2: C,
63.11; H, 5.41. Found: C, 63.05; H, 5.35.
1
nix, AZ). H, 13C{1H}, and 31P{1H} NMR spectra were col-
lected on a Bruker-400 spectrometer (400 MHz) or a Bruker
ARX-300 spectrometer (300 MHz). 1H and 13C NMR shifts are
relative to TMS, and 31P chemical shifts are relative to 85%
H3PO4. MS spectra were recorded on a Finnigan TSQ7000
spectrometer.
Synthesis of CpOsCl(PPh3)2 (1). A mixture of freshly distil-
lated cyclopentadiene (50 μL, 0.61 mmol) and OsH3Cl(PPh3)3
(208 mg, 0.20 mmol) in 10 mL of toluene was refluxed for 2 h.
After removal of the solvent, the residue was washed with
n-hexane and diethyl ether and dried under vacuum to give a yellow
solid. Yield: 102 mg, 61.1%. The NMR data match with the
literature values.16 1H NMR (400 MHz, CDCl3): δ 7.30-7.11 (m,
30H, PPh3), 4.31 (s, 5H, Cp). 31P{1H} NMR (161.97 MHz, CDCl3):
δ -2.51 ppm (s).
General Procedure for the Synthesis of (η5-C5H4R)OsCl
(PPh3)2 (7-11) Using Fulvenes 7S-11S. A solution of fulvene
in THF (5 mL) was added to a solution of OsH3Cl(PPh3)3 in
THF (5 mL). The mixture was refluxed for 4 h. After the
completion of the reaction, all volatiles were removed under
reduced pressure. The residue was purified by column chroma-
tography on aluminum oxide using n-hexane and 5:1 n-hexane/
Et2O as the eluting solvents. Removal of solvents afforded
corresponding cyclopentadienyl complexes as yellow solids.
(η5-C5H4CH2tolyl)OsCl(PPh3)2 (7). 6-Tolylfulvene (7S) (107
mg, 0.63 mmol), OsH3Cl(PPh3)3 (412 mg, 0.41 mmol). Yield:
259 mg, 69.4%. 1H NMR (300 MHz, CD2Cl2): δ 7.31-7.05 (m,
34H, PPh3 and aromatic protons of tolyl), 4.03 (s, 2H, C5H4),
3.71 (s, 2H, C5H4), 3.44 (s, 2H, CH2), 2.28 (s, 3H, Me of tolyl).
13C{1H} NMR (75.5 MHz, CD2Cl2): 139.32 (d, J=48.1 Hz),
133.95 (t, J = 4.7 Hz), 128.71 (s), 127.25 (t, J=4.4 Hz) (PPh3),
137.68 (s), 135.76 (s), 129.05 (s), 128.89 (Carom. of tolyl), 106.54
(s), 76.03 (s), 75.97 (s), 72.56 (s, C5H4), 32.26 (s, C5H4CH2-),
20.74 (s, CH3 of tolyl). 31P{1H}NMR (121.5 MHz, CD2Cl2): δ
-2.28 ppm (s). Anal. Calcd for C49H43ClOsP2: C, 64.01; H, 4.71.
Found: C, 64.23; H, 4.90.
Synthesis of (C9H7)OsCl(PPh3)2 (2). A mixture of indene
(90%) (50 μL, 0.38 mmol) and OsH3Cl(PPh3)3 (260 mg, 0.26
mmol) in 10 mL of toluene was refluxed for 18 h. The product
was purified by column chromatography using Al2O3 as the
solid phase. The indene and PPh3 were first eluted out by a
n-hexane/DCM (6:1) mixture. The product was then eluted out
with DCM. The product was isolated as an orange solid. Yield:
68.0 mg, 30.7%. The NMR data match with the literature
values. 1H NMR (400 MHz, CD2Cl2): δ 7.14-7.11 (m, 6H,
PPh3 and indenyl), 7.03 (br s, 25H, PPh3), 6.84-6.82 (m, 3H,
indenyl), 4.84 (s, 1H, indenyl), 4.18 (s, 2H, indenyl). 31P{1H}
NMR (161.97 MHz, CD2Cl2): δ -1.58 ppm (s).
General Procedure for the Synthesis of (η5-C5Me4R)OsCl
(PPh3)2 from Substituted Tetramethylcyclopentadienes (3-6).
A mixture of cyclopentadiene (ca. 1.5 equiv) and OsH3Cl
(PPh3)3 in 20 mL of toluene was refluxed for 4 h. After the
completion of the reaction, the solvent was removed by evaporation
under vacuum. The residue was washed with n-hexane and Et2O
and dried under vacuum to give a yellow solid.
(η5-C5H4CH2C6H4OMe)OsCl(PPh3)2 (8). 6-Anisolylfulvene
(8S) (110 mg, 0.60 mmol), OsH3Cl(PPh3)3 (403 mg, 0.40 mmol).
Yield: 212 mg, 57.1%. 1H NMR (300 MHz, C6D6): δ 7.74 (br,
10H, PPh3), 7.40 (d, J = 8.5 Hz, C6H4OMe), 7.07 (br, 20H,
PPh3), 6.90 (d, J = 8.5 Hz, C6H4OMe), 4.33 (s, 2H, C5H4), 4.04
(s, 2H, CH2), 3.95 (s, 2H, C5H4), 3.45 (s, 3H, OMe). 13C{1H}
NMR (75.5 MHz, CD2Cl2): δ 139.42 (d, J = 49.1 Hz), 133.96
(s), 128.70 (s), 127.24 (s) (PPh3), 132 (s), 129.99 (s), 113.75 (s),
106.83 (s) (Carom. of anisolyl), 75.90 (s), 72.51 (s) (C5H4), 31.73
(s) (C5H4CH2), 13.93 (s) (OMe). 31P{1H} NMR (121.5 MHz,
C6D6): -2.38 ppm (s). Anal. Calcd for C49H43ClOOsP2: C,
62.91; H, 4.63. Found: C, 62.83; H, 4.77.
(C5Me5)OsCl(PPh3)2 (3). OsH3Cl(PPh3)3 (1.287 g, 1.27 mmol),
C5Me5H (300 μL, 1.92 mmol, 1.5 equiv). Reaction time: 4 h. Yield:
949 mg, 85%. 1H NMR (300 MHz, C6D6): δ 7.86 (br, 12H, PPh3),
7.04 (br, 18H, PPh3), 1.30 (s, 15H, CH3 of Cp*). 13C{1H} NMR
(75.45 MHz, CD2Cl2): δ 138.60 (d, J = 46.9 Hz), 135.08 (s), 128.49
(s), 126.83 (s) (PPh3), 86.50 (s) (C5Me5), 9.00 (s) (C5Me5). 31P{1H}
NMR (121.5 MHz, C6D6): δ -2.54 ppm (s). Anal. Calcd for
C46H45ClOsP2: C, 62.39; H, 5.12. Found: C, 62.37; H, 5.08.
(η5-C5Me4H)OsCl(PPh3)2 (4). OsH3Cl(PPh3)3 (331 mg, 0.33
mmol), C5Me4H2 (85%) (87 μL, 0.49 mmol, 1.5 equiv). Reaction
time: 4 h. Yield: 230 mg, 84.1%. 1H NMR (300 MHz, C6D6): δ
7.81 (br, 10H, PPh3), 7.05 (br, 20H, PPh3), 4.14 (s, 1H, CH of
C5Me4H), 1.38 (s, 6H, CH3 of C5Me4H), 1.23 (s, 6H, CH3 of
C5Me4H). 13C{1H} NMR (75.5 MHz, CD2Cl2): δ 138.98 (d, J=
47.9 Hz), 134.61 (s), 128.39 (s), 126.87 (s) (PPh3), 91.32 (s), 82.42
(s), 78.20 (s) (C5Me4H), 9.50 (s), 8.54 (s) (C5Me4H). 31P{1H}
NMR (121.5 MHz, C6D6): δ -2.73 ppm (s). Anal. Calcd for
C45H43ClOsP2: C, 62.02; H, 4.97. Found: C, 62.06; H, 4.77.
(η5-C5Me4Et)OsCl(PPh3)2 (5). OsH3Cl(PPh3)3 (211 mg, 0.21
mmol), C5Me4HEt (97%) (55 μL, 0.31 mmol, 1.5 equiv). Reac-
(η5-C5H4CHPh2)OsCl(PPh3)2 (9). 6,60-Diphenylfulvene (9S)
(102 mg, 0.44 mmol), OsH3Cl(PPh3)3 (0.300 mg, 0.30 mmol).
1
Yield: 196 mg, 67.6%. H NMR (300 MHz, C6D6): δ 7.85 (d,
J = 6.4 Hz, 4H, Ph), 7.73 (br, 12H, PPh3), 7.30 (br, 3H, Ph), 7.16
(t, J=6.4 Hz, 3H, Ph), 7.02 (br, 18H, PPh3), 6.35 (s, 1H, CHPh2),
4.17 (s, 2H, C5H4), 3.57 (s, 2H, C5H4). 31P{1H}NMR (121.5
MHz, C6D6): δ -1.41 ppm (s). Anal. Calcd for C54H45ClOsP2:
C, 66.08; H, 4.62. Found: C, 65.97; H, 4.67.
(η5-C5H4CH2tBu)OsCl(PPh3)2 (10). 6-tert-Butylfulvene (10S)
(60.0 mg, 0.45 mmol), OsH3Cl(PPh3)3 (203 mg, 0.20 mmol). Yield:
135 mg, 76.3%. 1H NMR (300 MHz, CD2Cl2): δ 7.23-7.02 (m,
30H, PPh3), 3.95 (s, 2H, C5H4), 3.65 (s, 2H, C5H4), 1.86 (s, 2H,
CH2), 0.81 (s, 9H, CH3). 13C{1H} NMR (75.5 MHz, CD2Cl2): δ
138.71 (d, J = 50.6 Hz), 133.12 (s), 127.79 (s), 126.37 (s) (PPh3),
102.43 (s), 77.12 (t, J=4.5 Hz), 71.56 (s, C5H4), 40.50 (s, C5H4CH2),
29.93 (s, CMe3), 28.76 (s, CMe3). 31P{1H} NMR (121.5 MHz,
CD2Cl2): δ -1.23 ppm (s). Anal. Calcd for C46H45ClOsP2: C,
62.39; H, 5.12. Found: C, 62.62; H, 5.16.
1
tion time: 6 h. Yield: 125.6 mg, 67.5%. H NMR (300 MHz,
C6D6): δ 7.86 (br, 12H, PPh3), 7.04 (br, 18H, PPh3), 1.77 (q, J =
7.4 Hz, 2H, CH2CH2), 1.40 (s, 6H, CH3 of C5Me4Et), 1.37
(s, 6H, CH3 of C5Me4Et), 0.92 (t, J=7.4 Hz, 3H, CH2CH3).
(39) Ferrando, G.; Caulton, K. G. Inorg. Chem. 1999, 38, 4168.
€
(40) Otter, A.; Muhle, H.; Neuenschwander, M.; Kellerhals, H. P.
Helv. Chim. Acta 1979, 62, 1626.
(41) Miller, S. A.; Bercaw, J. E. Organometallics 2004, 23, 1777.
(42) Stone, K. J.; Little, R. D. J. Org. Chem. 1984, 49, 1849.
(η5-C5H4cyclopentyl)OsCl(PPh3)2 (11A) and (η5-C5H4cyclo-
pentenyl)OsCl(PPh3)2 (11B). 6-Cyclopentylfulvene (11S) (43 mg,

3580 Organometallics, Vol. 29, No. 16, 2010
Tse et al.
0.32 mmol), OsH3Cl(PPh3)3 (203 mg, 0.20 mmol). Yield: 106 mg,
63.9%. Molar ratio of 11A to 11B = 4:1 (based on the integrations
of Cp proton signals). Characteristic 1H signals of 11A (300 MHz,
CD2Cl2): δ 4.11 (s, 2H, Cp), 3.87 (s, 2H, Cp), 2.90 (quintet, J = 8.3
Hz, 1H, CpCH of cyclopentyl), 2.19-2.13 (m, 2H cyclopentyl),
1.82-1.78 (m, 4H, cyclopentyl), 1.63-1.53 (m, 2H, cyclopentyl).
Characteristic signals of 11B (300 MHz, CD2Cl2): δ 5.90 (br t,
1H, =CH), 4.50 (s, 2H, C5H4), 3.83 (s, 2H, C5H4), 2.87 (br dt, 2H,
cyclopentyl), 2.19-2.13 (m, 2H, cyclopentyl), 1.82-1.78 (m, 2H,
cyclopentenyl). The 1H NMR signals of PPh3 in 11A and 11B are
overlapped in the region 7.48-7.15 ppm, and other CH2 signals are
overlapped in the region 2.65-1.28 ppm. 31P{1H} NMR (161.98
MHz, CD2Cl2): -2.10 (s, 11A), -2.80 ppm (s, 11B). Anal. Calcd
for C46H43ClP2Os: C, 62.54; H, 4.91. Found: C, 62.76; H, 4.98.
reaction was monitored by TLC. After the completion of the
reaction (19 h), the product was extracted with DCM (10 mL ꢀ 3),
washed with a brine solution (10 mL ꢀ 2), and dried over
Na2SO4. The product was purified by column chromatography
on basic aluminum oxide using hexane/ethyl acetate (10:1) as the
eluent. Yield: 244 mg (orange solid), 52.1%. 1H NMR (300
MHz, d-acetone): δ 8.41 (d, J = 5.6 Hz, 1H, aromatic H), 8.40 (s,
1H, aromatic H), 8.39 (d, J = 6.0 Hz, 1H, aromatic H), 8.35 (s,
1H, aromatic H), 8.32 (s, 1H, aromatic H), 8.29 (s, 2H, aromatic
H), 8.19 (t, J = 7.6 Hz, 1H, aromatic H), 8.09 (d, J = 7.6 Hz, 1H,
aromatic H), 7.82 (s, 1H, CH(pyrenyl)), 2.26 (s, 3H, CH3), 2.02
(s, 3H, CH3), 1.89 (s, 3H, CH3), 1.32 (s, 3H, CH3). 13C{1H}
NMR (75.5 MHz, d-acetone): 149.57 (s), 141.71 (s), 137.12 (s),
132.92 (s), 131.53 (s), 131.16 (s), 130.98 (s), 129.05 (s), 128.14 (s),
127.67 (s), 127.55 (s), 127.51 (s), 127.33 (s), 127.27 (s), 126.34
(s), 125.47 (s), 125.39 (s), 125.10 (s), 124.90 (s), 124.63 (s), 124.40
(s), 122.43 (s), 12.26 (s), 10.59 (s), 10.41 (s), 9.11 (s). MS (TOF
LD+): m/z 334.11 (M).
Synthesis of (η5-C5Me4CH2tolyl)OsCl(PPh3)2 (12). 6-Tolyl-
1,2,3,4-tetramethylfulvene (12S) (53 mg, 0.25 mmol, 1.6 equiv)
in toluene (6 mL) was added to a solution of OsH3Cl(PPh3)3 (155
mg, 0.15 mmol) in toluene (2 mL). The reaction mixture was
refluxed for 3.5 h. After the completion of the reaction, all
volatiles were removed under reduced pressure. The residue was
purified by column chromatography on Al2O3 with pentane/
diethyl ether (10:1) followed by pentane/DCM (1:1) as the
eluting solvents. Pure product was isolated as a yellow solid.
Yield: 113 mg, 75.9%. 1H NMR (400 MHz, CD2Cl2): δ 7.45 (br,
13H, PPh3), 7.17 (br, 7H, PPh3), 7.08 (br, 10H, PPh3), 6.95 (d,
J = 8 Hz, 2H, aromatic H of tolyl), 6.72 (d, J = 8 Hz, 2H,
aromatic H of tolyl), 2.56 (s, 2H, CH2-tolyl), 2.23 (s, 3H, CH3 of
Preparation of 6-Tolyl-1,2,3,4-tetramethylfulvene (12S). 1,2,3,4-
Tetramethylcyclopentadiene (85%) (250 μL, 1.40 mmol) was
added dropwisely to a Schlenk flask containing KOtBu (1.558 g,
13.88 mmol, 9.9 equiv) followed by addition of MeOH (8 mL) and
p-tolylaldehyde (97%) (230 μL, 1.88 mmol, 1.3 equiv). The mixture
was heated at 70 °C. The reaction was monitored by TLC. After
the completion of the reaction (15 h), the product was extracted
with n-pentane (10 mL ꢀ 3), washed with a brine solution (10 mL ꢀ
2), and dried over Na2SO4. The product was purified by column
chromatography on basic aluminum oxide using n-pentane as the
tolyl), 1.10 (s, 6H, CH3 of C5H4), 1.06 (s, 6H, CH3 of C5H4). 13
C
{1H} NMR (75.5 MHz, CD2Cl2): δ 138.41 (d, J = 46.9 Hz),
134.99 (s), 128.44 (s), 126.73 (s) (PPh3), 136.92 (s), 131.92 (s),
128.72 (s), 128.01 (s) (Carom. of tolyl), 87.26 (s), 86.93 (s), 85.88
(s) (C5Me4), 29.21 (s) (CH2-tolyl), 20.64 (s) (CH3 of tolyl), 9.31
(s), 8.96 (s) (C5Me4). 31P{1H} NMR (161.97 MHz, CD2Cl2): δ
-3.42 ppm (s). Anal. Calcd for C53H51ClP2Os: C, 65.25; H, 5.27.
Found: C, 62.65; H, 5.25.
1
eluent. Yield: 189 mg (orange oil), 60.2%. H NMR (300 MHz,
CDCl3): δ 7.36 (d, J = 7.9 Hz, 2H, Harom.of tolyl), 7.28 (d, J = 7.9
Hz, 2H, Harom.of tolyl), 7.22 (s, 1H, CH(tolyl)), 2.51 (s, 3H, CH3 of
tolyl), 2.22 (s, 3H, CH3 of C5Me4), 2.02 (s, 3H, CH3 of C5Me4), 1.98
(s, 3H, CH3 of C5Me4), 1.77 (s, 3H, CH3 of C5Me4). 13C{1H} NMR
(75.5 MHz, CDCl3): δ 146.69 (s), 141.96 (s), 137.32 (s), 137.03 (s),
134.57 (s), 130.49 (s), 129.62 (s), 128.63 (s), 125.66 (s), 122.48 (s),
21.40 (s), 13.59 (s), 11.44 (s), 11.35 (s), 9.84 (s). MS (TOF EI+): m/z
224.15 (M).
Synthesis of (η5-C5Me4CH2anisolyl)OsCl(PPh3)2 (13). 6-An-
isolyl-1,2,3,4-tetramethylfulvene (13S) (143 mg, 0.59 mmol, 1.3
equiv) in toluene (6 mL) was added to the solution of OsH3Cl
(PPh3)3 (461 mg, 0.45 mmol) in toluene (2 mL). The reaction
mixture was refluxed for 2 h. After the completion of the reac-
tion, all volatiles were removed under reduced pressure. The
product was washed with n-hexane and diethyl ether and dried
under vacuum. Yield: 345 mg, 76.6%. 1H NMR (300 MHz,
CD2Cl2): δ 7.57 (br, 13H, PPh3), 7.40-7.27 (m, 7H, PPh3), 7.20
(br, 10H, PPh3), 6.86 (d, J = 8.6 Hz, 2H, aromatic H of
anisolyl), 6.79 (d, J = 8.6 Hz, 2H, aromatic H of anisolyl),
3.82 (s, 3H, OCH3), 2.47 (s, 2H, CH2-anisolyl), 1.23 (s, 6H, CH3
of C5Me4), 1.19 (s, 6H, CH3 of C5Me4). 13C{1H} NMR (75.5
MHz, CD2Cl2): δ 157.75 (s), 132.06 (s), 129.04 (s), 113.45 (s)
(aromatic C of anisolyl), 138.42 (d, J=47 Hz), 135.01 (s), 128.45
(s), 126.74 (s) (PPh3), 87.14 (s), 86.96 (s), 86.11 (s) (C5Me4), 55.18
(s) (OCH3), 28.76 (s) (CH2-anisolyl), 9.31 (s), 8.96 (s) (C5Me4).
31P{1H} NMR (121.5 MHz, CD2Cl2): δ -3.38 ppm (s). Anal.
Calcd for C53H51ClOOsP2: C, 64.20; H, 5.18. Found: C, 64.38;
H, 5.09.
Preparation of 6-Anisolyl-1,2,3,4-tetramethylfulvene (13S).
1,2,3,4-Tetramethylcyclopentadiene (85%) (250 μL, 1.40 mmol)
was added dropwisely to a Schlenk flask containing KOtBu
(1.602 g, 14.28 mmol, 10.2 equiv) followed by addition of MeOH
(8 mL) and p-anisolylaldehyde (98%) (260 μL, 2.10 mmol, 1.5
equiv). The mixture was heated at 70 °C. The reaction was
monitored by TLC. After the completion of the reaction (19 h),
the product was extracted with n-pentane (10 mL ꢀ 3), washed
with a brine solution (10 mL ꢀ 2), and dried over Na2SO4. The
product was purified by column chromatography on basic
aluminum oxide using hexane/ethyl acetate (10:1) as the eluent.
Yield: 188 mg (orange oil), 55.7%. 1H NMR (300 MHz, d-ace-
tone): δ 7.39 (d, J=8.6 Hz, 2H, aromatic H), 7.14 (s, 1H, CH
(anisolyl)), 7.05 (d, J=8.6 Hz, 2H, aromatic H), 3.98 (s, 3H,
OCH3), 2.04 (s, 3H, CH3), 1.94 (s, 3H, CH3), 1.90 (s, 3H, CH3),
1.74 (s, 3H, CH3). 13C{1H} NMR (75.5 MHz, d-acetone): δ
159.53 (s), 146.59 (s), 141.29 (s), 136.05 (s), 131.14 (s), 129.63 (s),
129.36 (s), 125.38 (s), 121.71 (s), 113.36 (s), 154.73 (s), 133.07 (s),
10.50 (s), 10.47 (s), 9.04 (s). MS (TOF LD+): m/z 226.38 (M -
CH3).
Synthesis of (η5-C5Me4CH2pyrenyl)OsCl(PPh3)2 (14). 6-Pyr-
enyl-1,2,3,4-tetramethylfulvene (14S) (137 mg, 0.41 mmol, 1.3
equiv) in toluene (6 mL) was added to the solution of OsH3Cl
(PPh3)3 (321 mg, 0.32 mmol) in toluene (2 mL). The reaction
mixture was refluxed for 3 h. After the completion of the reac-
tion, all volatiles were removed under reduced pressure. The
product was washed with n-hexane and diethyl ether and dried
under vacuum. Yield: 263 mg, 76.6%. 1H NMR (300 MHz,
CD2Cl2): δ 8.36-8.28 (m, 3H, pyrenyl), 8.16-8.04 (m, 5H,
pyrenyl), 7.66 (br, 12H, PPh3), 7.52 (d, J = 7.8, 1H, pyrenyl), 7.31
(br, 8H, PPh3), 7.25 (br, 10H, PPh3), 3.42 (s, 2H, CH2-pyrenyl), 1.35
Preparation of 6-Pyrenyl-1,2,3,4-tetramethylfulvene (14S).
1,2,3,4-Tetramethylcyclopentadiene (85%) (250 μL, 1.40 mmol)
was added dropwisely to a flask containing KOtBu (1.642 g,
14.63 mmol, 10.5 equiv) followed by addition of MeOH (5 mL)
and 1-pyrenylcarboxaldehyde (98%) (394 mg, 1.71 mmol, 1.22
equiv) in THF (5 mL). The mixture was heated at 70 °C. The

Article
Organometallics, Vol. 29, No. 16, 2010 3581
Table 1. Crystal Data and Structure Refinement for 3, 4, 6, 8, 10, 14S, and 12
3
4
6
8
10
14S
C26H22
12
formula
fw
C
46H45-
ClOsP2
C45H43
ClOsP2
871.38
-
C48H49ClOsP2
CH2Cl2
998.39
C49H43
ClOOsP2
935.42
-
C46H45
ClOsP2
885.41
-
C53H51ClOsP2 +
0.5CH2Cl2
1017.99
3
885.41
334.44
˚
wavelength, A
cryst syst
space group
0.71073
monoclinic
P2(1)/c
17.135(2)
10.6770(13)
20.526(3)
90
101.6230(10)
90
3678.2(8)
4
1.599
3.660
1776
2.03-26.00
36 908
7175 (R(int)
= 0.0371)
7175/0/456
1.54178
monoclinic
I2/a
20.6600(2)
10.64450(10)
34.0135(4)
90
102.7770(10)
90
7294.87(13)
8
1.587
8.343
3488
2.66-67.00
12 670
6259 (R(int)
= 0.0307)
6259/0/451
1.54178
triclinic
P1
0.71073
monoclinic
P2(1)/c
17.1453(6)
10.1364(4)
23.1151(8)
90
95.258(3)
90
4000.3(3)
4
1.553
3.372
1872
2.34-26.00
30 557
7725 (R(int)
= 0.1053)
7725/0/488
1.54178
monoclinic
P2(1)/c
12.3351(2)
10.5747(2)
29.3780(6)
90
94.228(2)
90
3821.64(12)
4
1.539
7.972
1776
3.59-67.50
15 058
6702 (R(int)
= 0.0622)
6702/6/454
1.54178
monoclinic
P2(1)/c
29.3956(9)
6.5728(2)
9.5187(3)
90
99.019(2)
90
1816.38(10)
4
1.223
0.518
712
6.91-67.50
9931
3204 (R(int)
= 0.0405)
3204/0/239
0.71073
monoclinic
P2(1)/n
12.51560(10)
20.4199(2)
17.1641(2)
90
94.4070(10)
90
4373.61(8)
4
1.546
3.148
2052
2.32-29.04
55 911
10873 (R(int)
= 0.0673)
10 873/2/531
˚
a, A
10.8929(3)
12.7255(3)
16.4403(5)
78.940(2)
71.202(3)
87.621(2)
2116.78(10)
2
1.566
8.401
1004
3.54-71.28
27 991
˚
b, A
˚
c, A
R, deg
β, deg
γ, deg
V, A
Z
˚
Dcalcd, g cm-3
abs coeff, mm-1
F(000)
θ range, deg
no. of reflns
no. of
indep reflns
no. of data/
restraints/params
goodness of fit
on F2
7679 (R(int)
= 0.0252)
7679/2/519
1.010
1.001
1.002
1.057
1.026
1.005
1.027
final R indices
(I > 2σ(I))
largest diff
peak and
R1 = 0.0213, R1 = 0.0367,
wR2 = 0.0473 wR2 = 0.0806
R1 = 0.0210,
wR2 = 0.0519
0.932 and
R1 = 0.0687,
wR2 = 0.0888
1.556 and
R1 = 0.0392,
wR2 = 0.0656
0.995 and
R1 = 0.0432,
wR2 = 0.1074
0.198
R1 = 0.0422,
wR2 = 0.0726
1.394 and
1.473 and
-0.401
3.455 and
-1.321
-0.958
-3.251
-0.920
and -0.131
-2.273
-3
˚
hole, e A
(s, 6H, CH3 of C5Me4), 1.21 (s, 6H, CH3 of C5Me4). 13C{1H}NMR
(75.5 MHz, CD2Cl2): δ 138.43 (d, J = 48 Hz), 135.05 (s), 128.55 (s),
126.86 (s) (PPh3), 133.60 (s), 131.48 (s), 130.92 (s), 129.52 (s), 128.68
(s), 127.40 (s), 127.04 (s), 126.55 (s), 125.94 (s), 124.93 (s), 124.83 (s),
124.75 (s), 124.72 (s), 124.60 (s), 124.52 (s), 123.50 (s) (pyrenyl), 88.65
(s), 87.19 (s), 83.99 (s) (C5Me4), 26.65 (s) (CH2-pyrenyl), 9.12 (s), 9.06
(s) (C5Me4). 31P{1H} NMR (121.5 MHz, CD2Cl2): δ -3.38 ppm (s).
Anal. Calcd for C62H53ClOsP2: C, 68.59; H, 4.92. Found: C, 68.65;
H, 5.01.
X-ray Crystallography Studies of 3, 4, 6, 8, 10, 14S, and 12. The
crystal of 14S suitable for X-ray analysis was obtained by slow
evaporation of solvent of a methanol/hexane (1:3) solution.
Single crystals of others were obtained by layer diffusion using
a DCM/n-hexane mixture at room temperature. The crystals
were mounted on a glass fiber. The diffraction intensity data of 3
were collected with a Bruker Smart APEX CCD X-ray diffracto-
meter at T = 100 K. The diffraction intensity data of the rest were
collected with an Oxford Diffraction Gemini S Ultra X-ray
diffractometer. Data of 4, 6, 8, 10, and 12 were collected at
T = 173 K, while those for 14S were collected at T = 203 K.
Lattice determination and data collection of 3 were carried out
using SMART v.5.625 software. Data reduction and absorption
correction by empirical methods were performed using SAINT
v 6.26 and SADABS v 2.03, respectively. Lattice determination,
data collection, and reduction of the rest were carried out using
CrysAlisPro 171.33.46. Absorption correction was performed
using SADABS built into the CrysAlisPro program suite. Struc-
ture solutionandrefinement for all datawereperformed using the
SHELXTL v.6.10 software package. All the structures were
solved by direct methods, expanded by difference Fourier synth-
eses, and refined by full-matrix least-squares on F2. All non-
hydrogen atoms were refined anisotropically with a riding model
for the hydrogen atoms, except for those disordered groups that
have been re-examined and refined as a disordered model with
appropriate partial occupancies applied. Further details on crys-
tal data, data collection, and refinements are summarized in
Table 1.
Acknowledgment. This work was supported by the
Hong Kong Research Grant Council (HKUST 601306
and HKU1/CRF/08).
Supporting Information Available: X-ray crystallographic
files (CIF). This material is available free of charge via the
Internet at http://pubs.acs.org.