Selective lithiation and phosphane-functionalization of [(η7-C7H7)Ti(η5-C 5H5)] (troticene) and its use for the preparation of early-late heterobimetallic complexes

Article abstract of DOI:10.1021/ja9080056

The cycloheptatrienyl-cyclopentadienyl sandwich complex [(η⁷-C₇H₇)Ti(η⁵-C ₅H₅)] (troticene) can be dilithiated (once at each ring) or selectively monolithiated, either at the seven- or five

Full text of DOI:10.1021/ja9080056

Published on Web 10/28/2009
Selective Lithiation and Phosphane-Functionalization of
[(η7-C7H7)Ti(η5-C5H5)] (Troticene) and Its Use for the
Preparation of Early-Late Heterobimetallic Complexes
Swagat K. Mohapatra, Susanne Bu¨schel, Constantin Daniliuc, Peter G. Jones, and
Matthias Tamm*
Institut fu¨r Anorganische und Analytische Chemie, Technische UniVersita¨t Carolo-Wilhelmina,
Hagenring 30, 38106 Braunschweig, Germany
Received September 21, 2009; E-mail: m.tamm@tu-bs.de
Abstract: The cycloheptatrienyl-cyclopentadienyl sandwich complex [(η7-C7H7)Ti(η5-C5H5)] (troticene) can
be dilithiated (once at each ring) or selectively monolithiated, either at the seven- or five-membered ring,
depending on the reaction conditions. Treatment of the resulting lithiotroticenes with ClPPh2 afforded the
corresponding troticenyl-phosphanes [(η7-C7H6PPh2)Ti(η5-C5H4PPh2)] (1), [(η7-C7H6PPh2)Ti(η5-C5H5)] (2),
or [(η7-C7H7)Ti(η5-C5H4PPh2)] (3). The use of nBuLi/N,N′,N′,N′′,N”-pentamethyldiethylenetriamine (pmdta)
allowed us to isolate the lithium complexes [(η7-C7H6Li)Ti(η5-C5H4Li)]·pmdta (4) and [(η7-C7H7)Ti(η5-
C5H4Li)]·pmdta (5), which were structurally characterized by X-ray diffraction analyses. Reaction of the
monophosphane 3 with Mo(CO)6 and [(tht)AuCl] (tht ) tetrahydrothiophene) afforded the heterobimetallic
complexes [(3)Mo(CO)5] (6) and [(3)AuCl] (7) and also the trimetallic species [(3)2AuCl] (8). The reaction
of trans-[PtCl2(SEt2)2] with the diphosphane 1 led to the formation of cis-[(1)PtCl2] (9), whereas the complexes
trans-[(2)2PtCl2] (10) and trans-[(3)2PtCl2] (11) were isolated by reaction of two equivalents of the
monophosphanes 2 and 3 with trans-[PtCl2(SEt2)2]. The X-ray crystal structures of 6-11 are also reported.
Introduction
In stark contrast, the modification of other sandwich complexes
is significantly less developed and, for instance, little use has
Ever since the first isolation of ferrocene,1 this compound
has displayed a wide range of intriguing and useful forms of
chemical reactivity,2 and its modification has become an
important task in organometallic chemistry.3 Lithiation at the
cyclopentadienyl rings proved to be of particular importance
for the functionalization of the ferrocene moiety,4,5 and conse-
quently, lithioferrocenes are often encountered as intermediates
in the synthesis of ferrocenyl mono- and diphosphane ligands,6
which have attracted considerable attention because of their
relevance for a number of transition metal-catalyzed reactions.2,6
been made of sandwich complexes containing cycloheptatrienyl
(Cht) ligands, even though mixed cycloheptatrienyl-cyclopenta-
dienyl (Cht-Cp) complexes of the type [(η7-C7H7)M(η5-C5H5)]
(M ) group 4-6 metals) have been known for more than three
decades.7 Only recently,8 the interest in these early transition
metal Cht-Cp complexes has become revitalized by indepen-
dent reports from Elschenbroich, Braunschweig and Tamm on
the preparation of ansa-Cht-Cp complexes,9-11 which involved
in all cases the generation of dilithio complexes [(η7-C7H6Li)M(η5-
C5H4Li)] (M ) Ti, V, Cr) of type I (Scheme 1) in the presence
of N,N,N′,N′-tetramethylethylenediamine (tmeda).
(1) (a) Keely, T. J.; Pauson, P. L. Nature 1951, 168, 1039. (b) Miller,
S. A.; Tebboth, J. A.; Tremaine, J. F. J. Chem. Soc. 1952, 632. (c)
Adams, R. D. J. Organomet. Chem. 2001, 637–639.
Clearly, dilithiation can be achieved conveniently for all three
Cht-Cp complexes, troticene (M ) Ti), trovacene (M ) V)
and trochrocene (M ) Cr), and it should be noted that
(2) (a) Ferrocenes; Stepnicka, P., Ed.; Wiley-VCH: Weinheim, Germany,
2008. (b) Ferrocenes; Togni, A., Hayashi, T., Eds.; Wiley-VCH:
Weinheim, 1995.
(3) (a) Herbert, D. E.; Mayer, U. F. J.; Manners, I. Angew. Chem., Int.
Ed. 2007, 46, 5060. (b) Bellas, V.; Rehahn, M. Angew. Chem., Int.
Ed. 2007, 46, 5082. (c) Osakada, K.; Sakano, T.; Horie, M.; Suzaki,
Y. Coord. Chem. ReV. 2006, 250, 1012. (d) Siemeling, U.; Auch, T.-
C. Chem. Soc. ReV. 2005, 34, 584. (e) Stepnicka, P. Eur. J. Inorg.
Chem. 2005, 3787. Atkinson, R. C. J.; Gibson, V. C.; Long, N. J.
Chem. Soc. ReV. 2004, 33, 313. (f) Nguyen, P.; Go`mez-Elipe, P.;
Manners, I. Chem. ReV. 1999, 99, 1515.
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2017. (b) Arraya`s, R. G.; Adrio, J.; Carretero, J. C. Angew. Chem.,
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G.; Parisel, S. L. Coord. Chem. ReV. 2004, 248, 2131. (d) Colacot,
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(4) For dilithiation, see for instance: (a) Bishop, J. J.; Davison, A.; Katcher,
M. L.; Lichtenberg, D. W.; Merrill, R. E.; Smart, J. C. J. Organomet.
Chem. 1971, 27, 241. (b) Kovar, R. F.; Rausch, M. D.; Rosenberg, H.
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2005, 44, 5647. (b) Bartole-Scott, A.; Braunschweig, H.; Kupfer, T.;
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25, 4433. (d) Braunschweig, H.; Kupfer, T.; Lutz, M.; Radacki, K.
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J. Org. Chem. 1995, 60, 2502. (b) Bildstein, B.; Malaun, M.; Kopacka,
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17014 J. AM. CHEM. SOC. 2009, 131, 17014–17023
10.1021/ja9080056 CCC: $40.75  2009 American Chemical Society

Selective Functionalization of Troticene
A R T I C L E S
electron sandwich moieties.16 Finally, reports on the mono-
metalation of trochrocene are scarce, and we are only aware of
an early report from Fischer and Breitschaft, who observed that
metalation with amyl sodium occurred mainly, but not exclu-
sively, at the five-membered ring.17 However, the yields were
reported to be extremely low, and no metalation at all was
achieved by the use of lithium reagents such as PhLi or
nBuLi.12,17
Scheme 1. Lithiation of Cycloheptatrienyl-Cyclopentadienyl
Sandwich complexes
Since monolithiation of troticene was reported to occur
exclusively at the seven-membered ring (Vide supra), only the
troticenyl phosphane 2 was previously accessible by this route.15
Only recently, we reported a method for the synthesis of the
isomeric phosphane [(η7-C7H7)Ti(η5-C5H4PPh2)] (3), which
involved the reduction of the half-sandwich complex [(η5-
C5H4PPh2)TiCl3] with magnesium in the presence of cyclohep-
tatriene (Scheme 2).18 It should be noted, however, that
preparation of this starting material and of the phosphane-
functionalized cyclopentadienyl ligand precursor is rather tedious
and requires two lithiation steps. Accordingly, direct function-
alization of troticene at the five-membered ring would be
advantageous and would also allow direct access to other
functionalized troticene species, and we therefore became
interested in reinvestigating the lithiation of troticene with the
objective of gaining full control over the selectivity of this
reaction. As a result, we report herein the selective mono- and
dilithiation of troticene and its use for the high-yield preparation
of the phosphane ligands 1, 2, and 3 together with a number of
their transition metal complexes. In addition, the X-ray crystal
structures of lithio complexes of type I and III are provided.
Scheme 2. Preparation of Phosphane-Functionalized Troticenes
dilithiation of troticene had been observed for the first time as
early as 1974 by de Liefde Meijer.12 Fifteen years later, Rausch
and co-workers provided a viable protocol for the isolation of
the titanium species [(η7-C7H6Li)Ti(η5-C5H4Li)]·tmeda and its
use for the preparation of troticenyl diphosphane ligands such
as [(η7-C7H6PPh2)Ti(η5-C5H4PPh2)] (dppti, 1) (Scheme 2).13,14
Surprisingly, the picture is much less clear-cut for the monolithio
complexes [(η7-C7H6Li)M(η5-C5H5)] (II) and [(η7-C7H7)M(η5-
C5H4Li)] (III): For troticene, monolithiation was reported to
proceed exclusively at the seven-membered ring (Scheme 1,
type II),12,14 which allowed, inter alia, the selective synthesis
of troticenyl monophosphanes such as [(η7-C7H6PPh2)Ti(η5-
C5H5)] (2).15 In contrast, lithiation of trovacene was achieved
exclusively at the five-membered ring, and the resulting [(η7-
C7H7)V(η5-C5H4Li)] intermediate (Scheme 1, type III) was
mainly involved in the preparation of numerous poly(trovacenes)
that were used to study the intermetallic communication
(exchange coupling) between the resulting paramagnetic 17-
Results and Discussion
Dilithiation of Troticene. Although the dilithiation of troticene
with n-butyllithium and tmeda is well-established, we were
interested in identifying the optimum conditions for the genera-
tion of dilithiotroticene [(η7-C7H6Li)Ti(η5-C5H4Li)] and also in
structurally characterizing this reactive intermediate. In our
hands, the best results were obtained when the preformed
lithiating reagent, prepared from equimolar amounts of n-
butyllithium and N,N′,N′,N′′,N′′-pentamethyldiethylenetriamine
(pmdta), is slowly added to a suspension of troticene in hexane,
followed by stirring overnight. Filtration and washing with
hexane afforded a green pyrophoric solid in high yield (86%),
which can be stored for several days under an inert atmosphere
at room temperature. As indicated by elemental analysis, this
material has the composition [(η7-C7H6Li)Ti(η5-C5H4Li)]·pmdta
(4) and is sufficiently pure to be used directly for further
transformations.
(16) (a) Elschenbroich, C.; Plackmeyer, J.; Nowotny, M.; Behrendt, A.;
Harms, K.; Pebler, J.; Burghaus, O. Chem.sEur. J. 2005, 11, 7427.
(b) Elschenbroich, C.; Plackmeyer, J.; Nowotny, M.; Harms, K.; Pebler,
J.; Burghaus, O. Inorg. Chem. 2005, 44, 955. (c) Elschenbroich, C.;
Wolf, M.; Pebler, J.; Harms, K. Organometallics 2004, 23, 454. (d)
Elschenbroich, C.; Plackmeyer, J.; Harms, K.; Burghaus, O.; Pebler,
J. Organometallics 2003, 22, 3367. (e) Elschenbroich, C.; Wolf, M.;
Schiemann, O.; Harms, K.; Burghaus, O.; Pebler, J. Organometallics
2002, 21, 5810. (f) Elschenbroich, C.; Lu, F.; Harms, K. Organome-
tallics 2002, 21, 5152. (g) Elschenbroich, C.; Schiemann, O.; Burghaus,
O.; Harms, K.; Pebler, J. Organometallics 1999, 18, 3273. (h)
Elschenbroich, C.; Wolf, M.; Burghaus, O.; Harms, K.; Pebler, J. Eur.
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(11) (a) Tamm, M.; Kunst, A.; Bannenberg, T.; Herdtweck, E.; Sirsch, P.;
Elsevier, C. J.; Ernsting, J. M. Angew. Chem., Int. Ed. 2004, 43, 5530.
(b) Tamm, M.; Kunst, A.; Herdtweck, E. Chem. Commun. 2005, 1729.
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Organometallics 2007, 26, 417.
(12) Groenenboom, C. J.; de Liefde Meijer, H. J.; Jellinek, F. J. Organomet.
Chem. 1974, 69, 235.
(13) (a) Rausch, M. D.; Ogasa, M.; Ayers, M. A.; Rogers, R. D.; Rollins,
A. N. Organometallics 1991, 10, 2481. (b) Kool, L. B.; Ogasa, M.;
Rausch, M. D.; Rogers, R. D. Organometallics 1989, 8, 1785. (c)
Ogasa, M.; Rausch, M. D.; Rogers, R. D. J. Organomet. Chem. 1991,
403, 279.
(14) Rausch, M. D.; Ogasa, M.; Rogers, R. D.; Rollins, A. N. Organome-
tallics 1991, 10, 2084.
(17) Fischer, E. O.; Breitschaft, S. Chem. Ber. 1966, 99, 2905.
(18) Bu¨schel, S.; Jungton, A.-K.; Bannenberg, T.; Randoll, S.; Hrib, C. G.;
Jones, P. G.; Tamm, M. Chem.sEur. J. 2009, 15, 2176.
(15) (a) Demerseman, B.; Dixneuf, P. H. J. Organomet. Chem. 1981, 210,
C20. (b) Demerseman, B.; Dixneuf, P. H.; Douglade, J.; Meicier, R.
Inorg. Chem. 1982, 21, 3942.
(19) Walczak, M.; Walczak, K.; Mink, R.; Rausch, M. D.; Stucky, G. J. Am,
Soc. 1978, 100, 6382.
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A R T I C L E S
Mohapatra et al.
Scheme 3. Dilithiation of Troticene and Preparation of
1,1′-Bis(diphenylphosphanyl)troticene (1)
thf complexes [(η6-C6H5Li)2Cr]2 · 7thf,21 [(η6-C6H5Li)2Mo]2 ·
6thf,22 and [(η6-C6H5Li)2V]2 · 7thf23 exhibit more strongly
distorted molecular structures.
The crystal structure of dilithiated trochrocene, [(η5-
C5H4Li)Cr(η7-C7H6Li)]2 ·8thf, displays a closely related dimeric
arrangement with the terminal Li atoms stabilized by thf
coordination.10d It is interesting to note, however, that this
structure is inverted with regard to the positions of the Cht and
Cp rings, and in contrast to 4, the ipso-C5H4 carbon atoms adopt
the bridging position in the central Li2C2 rhomboid. This
difference is a clear indication of the different metalation
behavior of the Cp and Cht ligands in troticene and trochrocene.
Whereas the chromium-carbon distances in the latter structure
are very similar, the titanium-carbon distances to the seven-
membered rings [2.175(2)-2.219(2) Å/2.172(2)-2.217(2) Å]
are significantly shorter than those to the five-membered rings
[2.292(2)-2.356(2) Å/2.295(2)-2.362(2) Å], revealing, as
expected for troticene,24 a much stronger interaction between
the metal center and the Cht ring.8,25 With regard to the position
of the bridging lithium atoms in 4, this molecular structure could
beregardedasanansa-Cht-Cpcomplexorlithia[1]troticenophane,
respectively. In contrast to other covalently linked troti-
cenophanes,11 however, bridging of the Cht and Cp rings by
lithium does not impose appreciable strain on the troticene
sandwich structure, as indicated by the angles 2.9° (molecule
1) and 4.2° (molecule 2) between the best planes of the five-
and seven-membered rings.
To test the suitability of the dilithio complex 4 as a starting
material for the preparation of functionalized troticenes, it was
further used for the preparation of the previously reported
troticenyl diphosphane dppti (1);13 addition of an ethereal
solution of chlorodiphenylphosphane to a suspension of 4 in
diethyl ether afforded 1 as a blue-green solid in high yield (92%,
Scheme 3). Although Rausch reported a similar yield via
lithiation with nBuLi/tmeda,13b we have to conclude that, in
our hands, the use of pmdta and the isolation of the intermediate
4 has proved to be clearly superior. The 31P NMR spectrum of
4 exhibits two singlet resonances at 18.6 and -17.7 ppm for
the C7H6PPh2 and C5H4PPh2 phosphorus atoms, respectively,
and these values are virtually identical to those published
previously.13b
Figure 1. ORTEP view of [(η7-C7H6Li)Ti(η5-C5H4Li)]·pmdta (4). Molecule
1 is shown, and hydrogen atoms are omitted for clarity. Selected bond
lengths [Å] and angles [°] for molecule 1: Li1-C1 2.246(3), Li1-C1′
2.126(3), Li1-C8 2.170(3), Li2-C8 2.150(3), Li2-N1 2.115(3), Li2-N2
2.095(3), Li2-N3 2.120(3), Ti-CCht 2.175(2)-2.219(2), Ti-CCp 2.292(2)-
2.356(2); C1-Li1-C1′ 110.59(13), C1-Li1-C8 101.69(12), C8-Li1-C1′
147.29(14), Li1-C1-Li1′ 69.41(13), Li1-C8-Li2 83.05(11), N1-Li2-N2
88.02(11), N1-Li2-N3 116.58(13), N2-Li1-N3 87.02(11).
The composition of 4 was also confirmed spectroscopically;
1
the H NMR spectrum exhibits three broad multiplets for the
Cht (δ ) 6.24, 5.99, and 5.62 ppm) and a broad multiplet for
the Cp hydrogen atoms (δ ) 5.89 ppm), which is for both rings
downfield from the corresponding troticene resonances (δ )
4.90, C5H5; δ ) 5.42 ppm, C7H7). Furthermore, the isolation
of suitable single crystals of 4·toluene from a saturated toluene
solution at -30 °C allowed us to determine the X-ray crystal
structure of 4. The asymmetric unit contains two halves of two
independent centrosymmetric complexes of the type [(η7-
C7H6Li)Ti(η5-C5H4Li)]2 · 2pmdta (and one toluene molecule),
and Figure 1 shows the complete molecule 1 as a representative
of the two structurally closely related dimers. In each molecule,
the troticene units are connected by two symmetry-equivalent
bridging lithium atoms (Li1/Li1′ in molecule 1, Li3/Li3′ in
molecule 2). Each independent lithium atom is bound to one
carbon atom of each equivalent C7H6 ring (Li1 to C1/C1′, Li3
to C22/C22′) and to one carbon atom (Li1 to C8, Li3 to C29)
of the independent C5H4 ring, affording a central Li2C2 rhomboid
with lithium-carbon distances of 2.247(3) Å (Li1-C1) and
2.125(3) Å (Li1-C1′) in molecule 1 and 2.252(3) Å (Li3-C22)
and 2.108(3) Å (Li3-C22′) in molecule 2. These lithium atoms
display a distorted trigonal-planar environment, with angle sums
of 359.6° at Li1 and 358.8° at Li3. The two additional terminal
lithium atoms (Li2/Li2′, Li4/Li4′) in each molecule are bound
to the same C5H4 carbon atoms (Li2 to C8, Li4 to C29), which
thereby bridge the two types of Li atoms, and their coordination
sphere is completed by three pmdta nitrogen atoms to afford
highly distorted tetrahedral geometries. The same structural
motif has been observed for the dimeric pmdta complexes [(η5-
C5H4Li)2Fe] ·pmdta19 and [(η5-C5H4Li)Mn(η6-C6H5Li)] ·pmdta,20
and the Li-C and Li-N distances in 4 are in good agreement
with the values reported for these complexes. In contrast, the
Monolithiation of Troticene. As described above, monolithia-
tion of troticene has been reported to occur exclusively at the
seven-membered ring,12,14 which allowed, for instance, the
preparation of the monophosphane [(η7-C7H6PPh2)Ti(η5-C5H5)]
(2) in satisfactory yield.15 This route is fully reproducible and,
in our hands, 2 was isolated in 73% yield after stirring an
(21) Braunschweig, H.; Kupfer, T. Organometallics 2007, 26, 4634.
(22) Braunschweig, H.; Buggisch, N.; Englert, U.; Homberger, M.; Kupfer,
T.; Leusser, D.; Lutz, M.; Radacki, K. J. Am. Soc. 2007, 129, 4840.
(23) Braunschweig, H.; Kaupp, M.; Adams, C. J.; Kupfer, T.; Radacki,
K.; Schinze, S. J. Am. Soc. 2008, 130, 11376.
(24) Lyssenko, K. A.; Antipin, M. Y.; Ketkov, S. Y. Russ. Chem. Bull.
Int. Ed. 2001, 50, 130.
(20) Braunschweig, H.; Kupfer, T.; Radacki, K. Angew. Chem., Int. Ed.
2007, 46, 1630.
(25) Menconi, G.; Kaltsoyannis, N. Organometallics 2005, 24, 1189.
9
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Selective Functionalization of Troticene
A R T I C L E S
Scheme 4. Selective Monolithiation of Troticene and Preparation of
Isomeric Mono(diphenylphosphanyl)troticenes 2 and 3
Figure 2. ORTEP view of [(η7-C7H7)Ti(η5-C5H4Li)]·pmdta (5). Hydrogen
atoms are omitted for clarity. Selected bond lengths [Å] and angles [°]:
Li-C8 2.115(3), Li-N1 2.121(3), Li-N2 2.127(3), Li-N3 2.123(3),
Ti-CCht 2.224(2)-2.250(2), Ti-CCp 2.280(2)-2.335(2); C8-Li-N1
114.68(14), C8-Li-N2 123.76(15), C8-Li-N3 123.79(15), N1-Li-N2
85.60(12), N1-Li-N3 112.65(14), N2-Li-N3 87.95(12).
To unambiguously confirm lithium coordination at the Cp
ring, an X-ray crystal structure determination was performed
on single crystals of 5 that were obtained from a toluene solution
at -30 °C. The molecular structure of 5 is shown in Figure 2,
revealing that the lithium atom is bound to the C5H4 ring [Li-C8
) 2.115(3) Å]. The lithium coordination sphere is completed
by coordination of three pmdta nitrogen atoms to afford a highly
distorted tetrahedral environment with acute N1-Li-N2 and
N2-Li-N3 angles of 85.60(12)° and 87.95(12)°, respectively.
The orientation of the Cht and Cp ring planes deviates by 6.7°
from that expected for an ideal sandwich structure, which is
presumably a result of the steric requirements of the Li(pmdta)
moiety. It was calculated, however, that bending apart of the
Cht and Cp rings in troticene carries only a small energy
penalty.8 Naturally, the convenient isolation of the pmdta
complex 5 suggested that it should also be a superior starting
material for the preparation of the monophosphane [(η7-
C7H7)Ti(η5-C5H4PPh2)] (3), and indeed, this compound was
isolated in 84% yield from the reaction of ClPPh2 with 5 in
diethyl ether.
equimolar mixture of troticene and n-BuLi/hexane in diethyl
ether for 3 h at room temperature followed by addition of an
ethereal solution of ClPPh2 at -78 °C (Scheme 4). The 1H NMR
spectrum is in agreement with the previously published data.15b
In addition, the 31P NMR spectrum exhibits a singlet resonance
at 18.5 ppm, which is indicative of phosphorus-substitution at
the seven-membered ring.
We observed, however, that mixtures of the two regioisomers
[(η7-C7H6PPh2)Ti(η5-C5H5)] (2) and [(η7-C7H7)Ti(η5-C5H4PPh2)]
(3) were obtained if the nBuLi/troticene solution was allowed
to react for prolonged periods of time, indicating that the
lithiation at the five-membered ring might be thermodynamically
favored. Indeed, [(η7-C7H7)Ti(η5-C5H4PPh2)] (3) could be
isolated as the sole product in analytically pure form in 62%
yield after stirring in diethyl ether for 36 h, followed by
quenching with ClPPh2 (Scheme 4). The 31P NMR resonance
is observed at -17.5 ppm, which is a clear indication of
phosphorus-substitution at the five-membered ring. The spec-
troscopic data are in full agreement with those previously
published for a sample of 3, which had been prepared by the
reductive method shown in Scheme 2.18 Since amines have a
marked effect on the basicity of organolithium compounds26
and since the use of pmdta has also been beneficial for the
dilithiation of troticene (Vide supra), we anticipated that the
thermodynamically favored lithio complex [(η7-C7H7)Ti(η5-
C5H4Li)] should be conveniently accessible by reaction of
troticene with n-BuLi/pmdta in hexane. Consequently, a dark
green pyrophoric solid was isolated in almost quantitative yield
(95%) after stirring for 4.5 h at room temperature, followed by
filtration and washing with hexane. Elemental analysis indicated
that this material has the composition [(η7-C7H7)Ti(η5-
C5H4Li)]·pmdta (5) and is sufficiently pure to be used directly
for further transformations; it can also be stored under an inert
atmosphere at room temperature for several days and was fully
characterized by means of NMR spectroscopy. Thus, two
characteristic pseudotriplets corresponding to the R- and ꢀ-C5H4
Syntheses of Troticenyl Phosphane Metal Complexes. The
availability of the troticenyl diphosphane 1 and of the mono-
phosphanes 2 and 3 encouraged us to prepare a few selected
transition metal complexes and to compare their coordination
behavior with that of ferrocenyl phosphanes. Since several
transition metal complexes containing the monophosphane [(η7-
C7HPPh2)Ti(η5-C5H5)] (2) are known, for example, [(2)M(CO)x]
(M ) Ni, x ) 3; M ) Fe, x ) 4; M ) Mo, x ) 5),15 we aimed
at synthesizing similar complexes with its regioisomer [(η7-
C7H7)Ti(η5-C5H4PPh2)] (3). Thus, the reaction of 3 with
Mo(CO)6 in a boiling toluene/thf mixture afforded the molyb-
denum complex [(3)Mo(CO)5] (6) as a green solid in moderate
yield (Scheme 5). The strong low-field shift of the 31P NMR
resonance from -17.5 ppm in 3 to 23.0 ppm in 6 gives a clear
indication of metal-phosphane coordination. The IR spectrum
exhibits four CO absorptions at 2069 (A1(2)), 1981 (B1), 1934
(A1(1)) and 1917 (E) cm-1, which are similar to those recorded
for [(2)Mo(CO)5] (2080, 1995, 1940, and 1915 cm-l).15b Since
(2)
the A1 CO stretching mode has been used as a qualitative
indicator for comparison of the relative donor abilities of various
phosphanes,27 it can be concluded that the phosphane 3 is a
better donor than its regioisomer 2. Complex 6 was additionally
characterized by X-ray diffraction analysis, and the molecular
1
protons are observed at 6.05 and 5.67 ppm in the H NMR
spectrum together with a singlet resonance for the C7H7
hydrogen atoms at 5.61 ppm.
(26) (a) Seyferth, D. Organometallics 2006, 25, 2. (b) Seyferth, D.
Organometallics 2009, 28, 2.
(27) Palcic, J. D.; Baughman, R. G.; Golynski, M. V.; Frawley, S. B.; Peters,
R. G. J. Organomet. Chem. 2005, 690, 534.
9
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A R T I C L E S
Mohapatra et al.
Scheme 5. Preparation of Molybdenum and Gold(I) Complexes
Containing the (Diphenylphosphanyl)troticene 3a
a tht ) tetrahydrothiophene.
Figure 4. ORTEP view of one independent molecule of [(3)AuCl] (7).
Hydrogen atoms are omitted for clarity. Selected bond lengths [Å] and angles
[°] in molecule 1: Au1-P1 2.216(3), Au1-Cl1 2.287(3), Ti1-CCht
2.178(13) - 2.211(12), Ti1-CCp 2.287(14)-2.327(13); P1-Au1-Cl1
178.60(18). Molecule 2: Au2-P2 2.219(3), Au2-Cl2 2.302(3), Ti2-CCht
2.189(13)-2.218(13), Ti2-CCp 2.320(11)-2.376(14); P2-Au2-Cl2
178.63(15).
with the composition [(3)AuCl] (7). As also observed for the
Mo complex 6, phosphane coordination effects a pronounced
downfield shift of the 31P NMR resonance, which is observed
at 21.5 ppm. Complex 7 crystallizes in the space group P21
with two independent molecules and two thf molecules in the
asymmetric unit, and Figure 4 shows molecule 1 as a repre-
sentative of the two structurally closely related molecules. As
expected for Au(I) compounds, 7 displays a linear P-Au-Cl
axis31 with angles P1-Au1-Cl1 ) 178.60(18)° (molecule 1)
and P2-Au2-Cl2 ) 178.63(15)° (molecule 2). The P-Au
[2.216(3)/2.219(3) Å] and Au-Cl [2.287(3)/2.302(3) Å] dis-
tances in 7 are similar to those previously determined for gold(I)
chloride complexes containing (diphenylphosphanyl)ferrocene
ligands.29
Treatment of the gold(I) precursor [(tht)AuCl] with 2 equiv
of 3 afforded the 2:1 complex [(3)2AuCl] (8) as a turquoise
solid in good yield. The 31P NMR spectrum exhibits a single
resonance at 19.5 ppm (in CD2Cl2), indicating the presence of
two identical phosphorus nuclei. The molecular structure of 8
was established by X-ray diffraction analysis (Figure 5). The
molecule displays crystallographic C2 symmetry with the Au
and Cl atoms lying on the C2 axis. Accordingly, the gold(I)
atom is in a perfectly planar environment; nevertheless, its
coordination sphere is strongly distorted from ideal trigonal
planarity, since the P-Au-P′ angle [139.08(5)°] is significantly
larger than the P-Au-Cl/P′-Au-Cl angles [110.46(2)°]. The
Au-P and Au-Cl distances are 2.3167(9) Å and 2.5656(14)
Å, which is appreciably longer than the corresponding distances
in the monophosphane complex 7. This elongation is in
agreement with the trend observed for other three-coordinated
gold(I) complexes,32 including related P2AuCl complexes
containing ferrocenyl phosphane ligands.30
Figure 3. ORTEP view of [(3)Mo(CO)5] (6). Hydrogen atoms are omitted
for clarity. Selected bond lengths [Å] and angles [°]: Mo-P 2.5423(4),
Mo-C25 2.0397(15), Mo-C26 2.0542(14), Mo-C27 2.0548(15), Mo-C28
2.0428(14), Mo-C29 2.0113(16), Ti-CCht 2.1984(15)-2.2100(14), Ti-CCp
2.3337(13)-2.3428(12), P-C8 1.8154(13); P-Mo-C25 98.02(4), P-Mo-
C26 89.46(4), P-Mo-C27 86.06(4), P-Mo-C28 90.27(4), P-Mo-C29
175.50(5).
structure is shown in Figure 3. The Mo atom resides in a slightly
distorted octahedral environment, while the titanium atom
displays only a small deviation from an ideal sandwich structure
with a dihedral Cht-Cp angle of 4.1°. The Mo-P bond of
2.5423(4) Å is shorter than that determined for [(2)Mo(CO)5]
(2.563(2) Å),15b further corroborating the slightly stronger donor
ability of 3. Both Mo-P distances fall in the range observed
for other Mo(CO)5 complexes containing related metallo phos-
phane ligands.28
The monophosphane 3 was additionally employed in the
preparation of gold(I) complexes, since numerous Au(I) com-
plexes containing analogous ferrocenyl phosphane ligands have
been prepared and structurally characterized.29,30 The reaction
of 3 with 1 equiv of the Au(I) precursor compound [(tht)AuCl]
(tht ) tetrahydrothiophene) led to the formation of a green solid
For comparison of the ligand properties of the various
troticenyl mono- and diphosphanes, we aimed at the preparation
of a series of complexes in which 1-3 are coordinated to the
same complex fragment. The PtCl2 fragment was chosen, since
(28) (a) Hor, T. S. A.; Phang, L.-T.; Liu, L.-K.; Wen, Y.-S. J. Organomet.
Chem. 1990, 397, 29. (b) DuBois, D. L.; Eigenbrot, C. W., Jr.;
Miedaner, A.; Smart, J. C. Organometallics 1986, 5, 1405. (c) Phang,
L.-T.; Au-Yeung, S. C. F.; Hor, T. S. A.; Khoo, S. B.; Zhou, Z.-Y.;
Mak, T. C. W. J. Chem. Soc., Dalton Trans. 1993, 165.
(29) (a) Aguado, J. E.; Canales, S.; Gimeno, C. M.; Jones, P. G.; Laguna,
A.; Villacampa, M. D. Dalton Trans. 2005, 3005. (b) Ro¨ꢀler, K.;
Ru¨ffer, T.; Walfort, B.; Packheiser, R.; Holze, R.; Zharnikov, M.; Lang,
H. J. Organomet. Chem. 2007, 692, 1530. (c) Hill, D. T.; Girard, G. R.;
McCabe, F. L.; Johnson, R. K.; Stupik, P. D.; Zhang, J. H.; Reiff,
W. M.; Egglestons, D. S. Inorg. Chem. 1989, 28, 3529. (d) Canales,
F.; Gimeno, M. C.; Jones, P. G.; Laguna, A.; Sarroca, C. Inorg. Chem.
1997, 36, 5206. (e) Segapelo, T. V.; Guzei, I. A.; Darkwa, J. J.
Organomet. Chem. 2008, 693, 701.
(30) (a) Viotte, M.; Gautheron, B.; Kubicki, M. M.; Mugnier, Y.; Parish,
R. V. Inorg. Chem. 1995, 34, 3465. (b) Houlton, A.; Mingos, D. M. P.;
Murphy, D. M.; Williams, D. J.; Phan, L.-T.; Hor, T. S. A. J. Chem.
Soc., Dalton Trans. 1993, 3629. (c) Phang, L.-T.; Hor, T. S. A.; Zhou,
Z.-Y.; Mak, T. C. W. J. Organomet. Chem. 1993, 469, 253.
(31) Caravajal, M. A.; Novoa, J. J.; Alvarez, S. J. Am. Chem. Soc. 2004,
126, 1465.
(32) Gimeno, M. C.; Laguna, A. Chem. ReV. 1997, 97, 511.
9
17018 J. AM. CHEM. SOC. VOL. 131, NO. 46, 2009

Selective Functionalization of Troticene
A R T I C L E S
Figure 6. 31P NMR spectrum of 9 in CD2Cl2; the satellites are due to
31P-195Pt coupling, whereas the 31P-31P coupling is not resolved in this
presentation.
Figure 5. ORTEP view of [(3)2AuCl] (8). Hydrogen atoms are omitted
for clarity. Selected bond lengths [Å] and angles [°]: Au-P 2.3167(9),
Au-Cl 2.5656(14), Ti-CCht 2.184(4)-2.219(4), Ti-CCp 2.334(3)-2.377(4);
P-Au-P′ 139.08(5), P-Au-Cl 110.46(2).
Scheme 6. Preparation of Platinum(II) Complexes Containing the
Troticene-Phosphane Ligands 1, 2, and 3
numerous square-planar platinum(II) dichloride complexes
containing ferrocenyl phosphane ligands have been studied. In
particular, platinum complexes of 1,1′-bis(diphenylphosphanyl)-
ferrocene, [(η5-C5H4PPh2)2Fe] (dppf), have been studied exten-
sively in the past, and the dichloride [(dppf)PtCl2] has found
diverse applications, for example, in homogeneous catalysis33
and materials science,34 and has also been used for the
construction of supramolecular architectures35 and heteropoly-
metallic arrays36 and for the stabilization of numerous ligand
systems such as sulfur- or selenium-containing ligands,37
carboxylate ligands,38and hydridic species.39 In addition, ligand
exchange reactions at the (dppf)Pt moiety have been widely
studied, with particular emphasis on the interaction with ligands
of bioinorganic or medicinal relevance.40 The analogous
titanium-platinum complex cis-[(1)PtCl2] (9) was prepared in
high yield by the reaction of dppti (1) with trans-[PtCl2(SEt2)2]41
(Scheme 6). In agreement with the presence of two different
phosphorus nuclei, the 31P NMR spectrum of 9 displays two
doublets at 38.4 (C7H6PPh2) and 10.5 ppm (C5H4PPh2) with a
2J(31P-31P) coupling constant of 13.4 Hz (Figure 6). Further-
more, these resonances show large 31P-195Pt couplings of 3812
and 3780 Hz, respectively, which is in agreement with the
1J(31P-195Pt) coupling constant reported for [(dppf)PtCl2] (3778
Hz),42 although a lower range (3480-3680 Hz) has been
ascribed to cis-[PtCl2(PR3)2] complexes.43
The molecular structure of 9 was also established by X-ray
diffraction analysis (Figure 7), confirming the cis-configuration
of the P2PtCl2 moiety. The Pt atom resides in a square-planar
environment with a P1-Pt-P2 bite angle of 98.02(5)°, which
is slightly smaller than the corresponding angles reported for
the X-ray crystal structures of [(dppf)PtCl2] (99.0°),42
(33) (a) Vasapollo, G.; Toniolo, L.; Cavinato, G.; Bigoli, F.; Lanfranchi,
M.; Pellinghelli, M. A. J. Organomet. Chem. 1994, 481, 173. (b)
Wicht, D. K.; Zhuravel, M. A.; Gregush, R. V.; Glueck, D. S.; Guzei,
I. A.; Liable-Sands, L. M.; Rheingold, A. L. Organometallics 1998,
17, 1412. (c) Colacot, T. J.; Fair, R. J., Jr.; Boyko, W. J. Phosphorus,
Sulfur Silicon Relat. Elem. 1999, 144-146, 49. (d) Colacot, T. J.;
Qian, H.; Cea-Olivares, R.; Hernandez-Ortega, S. J. Organomet. Chem.
2001, 637-639, 691. (e) Zhang, F.; Ba¨uerle, P. J. Am. Chem. Soc.
2007, 129, 3090.
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De Souza Filho, J. D.; Ardisson, J. D.; Ayala, J. D.; Bombieri, G.
Polyhedron 2004, 23, 63. (b) Shavaleev, N. M.; Adams, H.; Best, J.;
Weinstein, J. A. J. Organomet. Chem. 2007, 692, 921.
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1996, 15, 904. (b) Bohle, D. S.; Stasko, D. Chem. Commun. 1998,
567. (c) Sun, S.-S.; Anspach, J. A.; Lees, A. J.; Zavalij, P. Y.
Organometallics 2002, 21, 685. (d) Teo, P.; Foo, D. M. J.; Koh, L. L.;
Hor, T. S. A. Dalton Trans. 2004, 3389. (e) Bar, A. K.; Chakrabarty,
R.; Mostafa, G.; Mukherjee, P. S. Angew. Chem., Int. Ed. 2008, 47,
8455. (f) Teo, P.; Koh, L. L.; Hor, T. S. A. Inorg. Chem. 2008, 47,
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Mak, T. C. W.; Hor, T. S. A. J. Chem. Soc., Dalton Trans. 1996,
2207. (b) Al-Allaf, T. A. K.; Schmidt, H.; Merzweiler, K.; Wagner,
C.; Steinborn, D. J. Organomet. Chem. 2003, 678, 48.
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G.; Demartin, F.; Manassero, M. Inorg. Chem. 1989, 28, 404. (b)
Haggerty, B. S.; Housecroft, C. E.; Rheingold, A. L.; Shaykh, B. A. M.
J. Chem. Soc., Dalton Trans. 1991, 2175. (c) Zhuravel, M. A.; Glueck,
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17, 574.
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Chim. 1988, 153, 67. (b) Corain, B.; Longato, B.; Favero, G.; Ajo,
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Dalton Trans. 1997, 3277. (d) Pettinari, C.; Marchetti, F.; Cingolani,
A.; Troyanov, S. I.; Drozdov, A. J. Chem. Soc., Dalton Trans. 1998,
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2002, 659, 107. (f) Knight, E. R.; Cowley, A. R.; Hogarth, G.; Wilton-
Ely, J. D. E. T. Dalton Trans. 2009, 607. (g) Knight, E. R.; Leung,
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2001, 20, 3189. (b) Noh, D. Y.; Seo, E. M.; Lee, H. J.; Jang, H. Y.;
Choi, M. G.; Kim, Y. H.; Hong, J. Polyhedron 2001, 20, 1939. (c)
Burchell, C. J.; Aucott, S. M.; Milton, H. L.; Slawin, A. M. Z.;
Woollins, J. D. Dalton Trans. 2004, 369. (d) Burchell, C. J.; Aucott,
S. M.; Slawin, A. M. Z.; Woollins, J. D. Dalton Trans. 2005, 735. (e)
Burchell, C. J.; Aucott, S. M.; Slawin, A. M. Z.; Woollins, J. D. Eur.
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Nieger, M.; Pietschnig, R. Inorg. Chem. 2005, 44, 2798.
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9
J. AM. CHEM. SOC. VOL. 131, NO. 46, 2009 17019

A R T I C L E S
Mohapatra et al.
Figure 7. ORTEP view of [(1)PtCl2] (9). Hydrogen atoms are omitted for
clarity. Selected bond lengths [Å] and angles [°]: Pt-P1 2.2507(15), Pt-P2
2.2672(15),Pt-Cl12.3506(13),Pt-Cl22.3433(15),Ti-CCht 2.153(5)-2.218(6),
Ti-CCp 2.293(5)-2.315(5); P1-Pt-P2 98.02(5), P1-Pt-Cl1 90.51(5),
P2-Pt-Cl2 84.81(5), Cl1-Pt-Cl2 86.90(5).
[(dppf)PtCl2]·CHCl3 (99.3°),44 and [(dppf)PtCl2]·0.5acetone
(99.3°).45 The Pt-P bond distances in 9 are also very similar
to those reported for the dppf analogue, with the Pt-P1 bond
[2.2507(15) Å] being somewhat shorter than Pt-P2 [2.2672(15)
Å]; this correlates with the slightly larger 31P-195Pt coupling
constant determined for the C7H6PPh2 phosphorus atom (Vide
supra). It should be noted that complex 9 can be regarded as a
[3]troticenophane with a P1-Pt-P2 bridge between the seven-
and five-membered rings; this three-atom bridge, however, does
not impose considerable strain, and the angle between the Cht
and Cp ring planes of 8.0° indicates only a relatively small
deviation from an unstrained sandwich structure.8
Figure 8. ORTEP views of [(2)2PtCl2] (10, top) and [(3)2PtCl2] (11,
bottom). Hydrogen atoms are omitted for clarity. Selected bond lengths
[Å] and angles [°] for 10: Pt-P 2.3386(9), Pt-Cl 2.3130(10), Ti-CCht
2.181(5)-2.220(4), Ti-CCp 2.300(5)-2.321(5); P-Pt-Cl 92.67(4), P-Pt-Cl′
87.33(4). 11: Pt-P 2.3215(8), Pt-Cl 2.3042(7), Ti-CCht 2.199(4)-2.223(3),
Ti-CCp 2.332(3)-2.340(3); P-Pt-Cl 92.87(3), P-Pt-Cl′ 87.13(3).
Fe(η5-C5H4PPh2)]47 and [(η5-C5H5CO2H)Fe(η5-C5H4PPh2)].48
The Pt-P and Pt-Cl bond lengths in 10 and 11 also fall in the
ranges found for these ferrocene analogs.
The reaction of trans-[PtCl2(SEt2)2] with 2 equiv of the
monophosphanes 2 and 3 afforded the complexes trans-
[(2)2PtCl2] (10) and trans-[(3)2PtCl2] (11) as green solids in good
yield. The trans-orientation of the phosphane ligands can be
assigned by 31P NMR spectroscopy, since the phosphorus
resonances of 10 (31.5 ppm) and 11 (6.7 ppm) show 31P-195Pt
couplings of 2652 and 2634 Hz, respectively, that are signifi-
cantly smaller than those in the cis-configured complex 9 and
fall in the range ascribed to trans-[PtCl2(PR3)2] complexes.42,43
Single crystals of 10·3CH2Cl2 and 11·2CH2Cl2 were subjected
to X-ray diffraction analyses, and the resulting molecular
structures exhibit the expected trans-configuration (Figure 8).
Both molecules display crystallographic inversion symmetry,
rendering the platinum environment perfectly planar with linear
P-Pt-P′ and Cl-Pt-Cl′ axes. The P-Pt-Cl and P-Pt-Cl′
angles in 10 and 11 are 92.67(4)°/87.33(4)° and 92.87(3)°/
87.13(3)°, respectively, revealing in both cases a slight distortion
from a perfectly square toward a rhomboid geometry. Interest-
ingly, the same crystallographic inversion symmetry was
observed for trans-P2PtCl2 complexes containing the related
(diphenylphosphanyl)ferrocene ligand, [(η5-C5H5)Fe(η5-C5H4-
PPh2)],46 or functionalized systems such as [(η5-C5H4OMe)-
Conclusion
Although the first reports on the lithiation of [(η7-C7H7)Ti(η5-
C5H5)] (troticene) appeared more than 30 years ago, our present
contribution demonstrates for the first time that selective mono-
and dilithiation of this 16-electron sandwich molecule can be
conveniently achieved. Whereas the previously observed mono-
lithiation at the Cht ring is apparently kinetically controlled,
the formation of the thermodynamically favored Cp-metalated
lithiotroticene is observed after prolonged reaction times; better
yet, this species is conveniently accessible by using a combina-
tion of n-BuLi and the triamine pmdta. Accordingly, selective
functionalization of troticene is possible, which has been
demonstrated by the syntheses of the troticenyl mono- and
diphosphanes 1-3. It should be noted that the transition metal
complexes derived from these phosphanes do not display any
secondary interactions involving the titanium atom, a situation
that is different from the reactivity of analogous zirconium- or
hafnium-based sandwich complexes.8,18,49,50 Therefore, tro-
(47) Atkinson, R. C. J.; Gibson, V. C.; Long, N. J.; White, A. J. P.;
Williams, D. J. Organometallics 2004, 23, 2744.
(44) Mu¨ller, A. Acta Crystallogr. 2007, E63, m210.
(45) Clemente, D. A.; Pilloni, G.; Corain, B.; Longato, V.; Tiripicchio-
Camellini, M. Inorg. Chim. Acta 1986, 115, L9.
(48) Stepnicka, P.; Podlaha, J.; Gyepes, R.; Polasek, M. J. Organomet.
Chem. 1998, 552, 293.
(49) Tamm, M.; Kunst, A.; Bannenberg, T.; Herdtweck, E.; Schmid, R.
Organometallics 2005, 24, 3163.
(46) (a) Otto, S.; Roodt, A. Acta Crystallogr. 1997, C53, 1414. (b) Long,
N. J.; White, A. J. P.; Williams, D. J.; Younus, M. J. Organomet.
Chem. 2002, 649, 94.
(50) Bu¨schel, S.; Bannenberg, T.; Hrib, C. G.; Glo¨ckner, A.; Jones, P. G.;
Tamm, M. J. Organomet. Chem. 2009, 694, 1244.
9
17020 J. AM. CHEM. SOC. VOL. 131, NO. 46, 2009

Selective Functionalization of Troticene
A R T I C L E S
Table 1. Crystallographic Data
4·toluene
5
6
7·THF
8
9
10·3CH2Cl2
11·2CH2Cl2
Empirical formula C49H74Li4N6Ti2 C21H34LiN3Ti C29H21MoO5PTi C28H29AuClOPTi C48H42AuClP2Ti2 C36H30Cl2P2PtTi C51H48Cl8P2PtTi2 C50H46Cl6P2PtTi2
a (Å)
b (Å)
c (Å)
R (deg)
ꢀ (deg)
γ (deg)
V (Å3)
Z
12.0047(4)
12.0319(4)
17.3320(6)
90.282(2)
94.171(4)
101.030(2)
2450.22(14)
2
20.9957(4)
7.9976(2)
12.6211(2)
90
90
90
31.9896(4)
10.0260(10)
17.1398(2)
90
107.5819(12)
90
10.2073(2)
13.3413(2)
18.5216(4)
90
91.036(2)
90
25.8727(10)
8.2464(2)
20.6849(8)
90
118.242(4)
90
10.3864(14)
13.1253(2)
22.9240(3)
90
90
90
11.4048(3)
15.3408(4)
14.5731(5)
90
98.262(3)
90
10.0746(6)
10.5051(10)
12.4587(8)
114.280(8)
92.360(6)
103.396(6)
1155.30(15)
1
2119.27(7)
4
5240.45(10)
8
2521.83(8)
4
3887.9(2)
4
3125.13(8)
4
2523.23(13)
2
formula weight
space group
T (°C)
870.70
P1
-173
0.71073
1.180
0.364
0.0331
0.0537
383.35
Pna21
-173
1.54184
1.201
3.461
0.0272
0.0731
624.27
C2/c
-173
0.71073
1.582
0.882
692.80
P21
-173
1.54184
1.825
15.189
0.0606
0.1495
1008.97
C2/c
-173
0.71073
1.724
4.352
838.43
P212121
-173
0.71073
1.782
5.026
0.0299
0.0337
1297.32
P21/n
-173
0.71073
1.708
3.597
1212.40
P 1
-173
0.71073
1.743
3.810
0.0242
0.0394
j
j
λ (Å)
Dcalcd (g cm-3
)
µ (mm-1
R(Fo)
)
0.0208
0.0429
0.0261
0.0531
0.0303
0.0547
2
Rw(Fo )
d8): δ 6.24 (m br, 2H, C7H6), 5.99 (m br, 2H, C7H6), 5.89 (m br,
4H, C5H4), 5.62 (m br, 2H, C7H6), 2.00-1.76 (br, 23H, pmdta).
Synthesis of [(η7-C7H7)Ti(η5-C5H4Li)]·pmdta (5). A suspen-
sion of troticene (0.5 g, 2.45 mmol) was prepared in 15 mL of
hexane at room temperature. In an additional flask, a solution of
lithiating agent was made from n-butyllithium (1.6 M, 2.57 mmol),
pmdta (0.54 mL, 2.57 mmol) in 7 mL of hexane. Then, the lithiating
mixture was stirred for 10 min and then slowly added to the original
suspension of troticene. The solution was stirred for 4.5 h, at which
time the blue solution had completely changed into a dark green
suspension. The solid was filtered off and washed repeatedly with
hexane. Drying under high vacuum yielded a dark green pyrophoric
crystalline solid (0.89, 95% yield). The solid can be stored for
several days under an inert atmosphere at room temperature.
Suitable crystals for X-ray analysis were obtained by cooling a
saturated solution of 5 · pmdta in toluene to -30 °C. Elemental
analysis (%) calcd for C21H34LiN3Ti: C, 65.80; H, 8.94; N, 10.96.
Found: C, 65.28; H, 8.85; N, 11.10. 1H NMR (600 MHz, benzene-
d6): δ 6.05 (t, 2H C5H4), 5.67 (t, 2H, C5H4), 5.61 (s, 7H, C7H7),
1.92-1.64 (br, 23H, pmdta). 13C{1H} NMR (150.9 MHz, benzene-
d6): δ 128.9 (s, i-C5H4), 112.0 (s, R-C5H4), 101.3 (s, ꢀ-C5H4), 83.5
(s, C7H7), 57.7 (s, CH2NMe2), 53.9 (s, CH2NMe), 46.2 (s, N(CH3)2),
45.3 (s, NCH3).
ticene, which is moderately air-stable in the solid-state, can be
regarded as an asymmetric analogue of ferrocene, and in view
of the ubiquity of ferrocene derivatives in the chemical sciences,
the potential for the development of an equally rich chemistry
based on the selective functionalization of troticene can be
envisaged.
Experimental Section
General Procedures. All operations were performed in a
glovebox in a dry argon atmosphere (MBraun 200B) or on a high-
vacuum line using Schlenk technique. Commercial grade solvents
were purified by a solvent purification system from MBraun GmbH
and stored over molecular sieves (4 Å) prior to their use.
Troticene,15b trans-Pt(SEt2)Cl241 and (tht)AuCl51 were synthesized
according to previous methodology reported in the literature.
n-Butyllithium (1.6 M in Hexane, Aldrich) and Mo(CO)6 (Aldrich)
were used as received. N,N′,N′,N′′,N′′-pentamethyldiethylenetri-
amine (Aldrich) was purified by distillation over CaH2. Chlo-
rodiphenylphosphane (Aldrich) was distilled under high vacuum.
Elemental analysis (C, H, N) was performed by combustion and
gas chromatographical analysis with an Elementar Vario MICRO
elemental analyzer. The 1H, 13C and 31P NMR spectra were recorded
on Bruker DPX 200 (200 MHz), Bruker AV 300 (300 MHz), Bruker
DRX 400 (400 MHz) and Bruker AVII 600 (600 MHz) devices.
The chemical shifts are expressed in parts per million (ppm) with
tetramethylsilane (TMS) as an internal standard. Coupling constants
(J) are reported in Hertz (Hz), and splitting patterns are indicated
as s (singlet), d (doublet), t (triplet), q (quartet), vq (virtual quartet),
m (multiplet), sept (septet), and br (broad). The reactions involving
gold were performed under exclusion of light.
Synthesis of [(η7-C7H6PPh2)Ti(η5-C5H4PPh2)] (1). A suspen-
sion of dilithiotroticene 4 (0.6 g, 1.53 mmol) was prepared in 15
mL of diethyl ether and the reaction vessel was chilled to -78 °C.
A solution of diphenylchlorophosphane (0.6 mL, 3.3 mmol) in
diethyl ether (7 mL) was slowly added via a dropping funnel to
the above reaction mixture, which was then allowed to warm slowly
to room temperature and was stirred overnight. At this time, a blue-
green suspension was obtained. All volatiles were removed under
vacuum and the residue was extracted in hot toluene and filtered
through Celite. The solvent was evaporated and the crude solid
was washed with hexane to remove excess of diphenylchlorophos-
phane. Drying the solid afforded a light blue-green solid 2 in high
yield (0.810 g, 92% yield). Elemental analysis (%) calcd for
C36H30P2Ti: C, 75.53; H, 5.28. Found: C, 74.36; H, 5.55. 1H NMR
(200 MHz, benzene-d6): δ 7.49 - 6.99 (m, 20H, PC6H5), 5.80 (t,
2H C7H6), 5.42 (m, 4H, C7H6), 5.05 (m, 4H, C5H4). 13C{1H} NMR
Synthesis of [(η7-C7H6Li)Ti(η5-C5H4Li)] ·pmdta (4). A slurry
of troticene (1.53 g, 7.50 mmol) was suspended in hexane (20 mL)
at room temperature. In an additional flask, a solution of the
lithiating agent was prepared by the addition of n-butyllithium (1.6
M, 18.75 mmol) and pmdta (3.9 mL, 18.75 mmol) in 10 mL of
hexane. The resulting mixture was stirred for 10 min and was then
slowly added to the above suspension of troticene via a dropping
funnel. The reaction, which gradually changed from blue slurry to
a dark-green suspension, was allowed to stir overnight. The solid
was isolated by filtration, followed by repeated washing with
hexane. The product was thoroughly dried under high vacuum,
affording a green pyrophoric solid in high yield (2.48 g, 86%).
The solid can be stored for several days under an inert atmosphere
at room temperature. X-ray quality crystals could be obtained by
cooling a saturated solution of 4 in toluene to -30 °C. Elemental
analysis (%) calcd for C21H33Li2N3Ti: C, 64.79; H, 8.54; N, 10.79.
Found: C, 64.32; H, 8.66; N, 11.37. 1H NMR (200 MHz, toluene-
1
(50.3 MHz, benzene-d6): δ 141.4 (d, JC-P ) 14.3 Hz, i-C6H5),
1
2
140.4 (d, JC-P ) 12.5 Hz, i-C6H5), 134.7 (d, JC-P ) 20.1 Hz,
2
o-C6H5), 134.5 (d, JC-P ) 20.2 Hz, o-C6H5) 133.4 (m, p-C6H5),
132.0 (m, p-C6H5), 129.5 (m, m-C6H5), 128.9 (m, m-C6H5), 111.0
(d, 1JC-P ) 10.2 Hz, i-C5H4), 104.7 (d, 2JC-P ) 13.5 Hz, R-C5H4),
3
1
101.9 (d, JC-P ) 13.5 Hz, ꢀ-C5H4), 95.1 (d, JC-P ) 10.8 Hz,
2
3
i-C7H6), 94.2 (d, JC-P ) 26.3 Hz, R-C5H4), 89.9 (d, JC-P ) 8.7
Hz, ꢀ-C5H4), 89.1 (m, γ-C7H6). 31P{1H}NMR (81 MHz, benzene-
d6): δ 18.6 (s, C7H6PPh2), -17.7 (s, C5H4PPh2).
Synthesis of [(η7-C7H6PPh2)Ti(η5-C5H5)] (2). Compound 2 was
synthesized according to a modification of the procedure outlined
(51) Uson, R.; Laguna, A.; Laguna, R. Inorg. Synth. 1989, 27, 85.
9
J. AM. CHEM. SOC. VOL. 131, NO. 46, 2009 17021

A R T I C L E S
Mohapatra et al.
by Dixneuf et al.15b To a blue suspension of troticene (0.475 mg,
2.32 mmol) in 20 mL of diethyl ether, 0.157 mL of 1.6 M
n-butyllithium (2.51 mmol) in hexane was added slowly via a
syringe at room temperature and the mixture was stirred for 3 h at
room temperature. During the reaction, the blue suspension gradu-
ally changed into a dark green solution. The resulting solution was
cooled to -78 °C and a solution of diphenylchlorophosphane (0.481
mL, 2.68 mmol) in 5 mL of diethyl ether was slowly added via a
dropping funnel. The reaction mixture was allowed to warm slowly
to room temperature and stirred overnight. All the volatiles were
evaporated under vacuum and the residue was extracted with toluene
and dried under vacuum. The green solid was washed with hexane
and dried under high vacuum affording 662 mg of 1 (73% yield).
1H NMR (200 MHz, benzene-d6): δ 7.53-7.02 (m, 10H, PC6H5),
5.82 (m, 2H C7H6), 5.41 (m, 4H, C7H6), 4.82 (s, 5H, C5H4).
31P{1H}NMR (81 MHz, benzene-d6): δ 18.5 (s, C7H6PPh2). These
values are in agreement with those reported previously.15b
131.6 (br, m-C6H5), 131.2 (br, p-C6H5), 128.9 (br, o-C6H5), 103.4
(R-C5H4), 101.2 (ꢀ-C5H4), 88.5 (C7H7). 31P{1H} NMR (81 MHz,
benzene-d6): δ 21.5 (s, PPh2).
Synthesis of [(3)2AuCl] (8). A total of 100 mg (0.26 mmol) of
3 was dissolved in 10 mL of thf and cooled to -30 °C. Over a
period of 30 min, this solution was added dropwise to a solution
of 41 mg (0.13 mmol) of [(tht)AuCl] and dissolved in 5 mL of thf,
at -78 °C. The reaction mixture was allowed to warm gradually
to room temperature and filtered through a plug of Celite. The
solvent was removed in high vacuum and the greyish-green residue
was extracted with CH2Cl2, filtered and dried, giving 8 as a turquoise
solid in good yields (83 mg, 0.08 mmol, 62%). 1H NMR (400 MHz,
dichloromethane-d2): δ 6.57 (m, 8H, o-C6H5), 6.17 (m, 10H, C6H5),
5.55 (br, 4H, R-C5H4), 5.50 (s, 14H, C7H7), 5.41 (br, 4H, ꢀ-C5H4).
1
13C{1H} NMR (100 MHz, dichloromethane-d2): δ 133.9 (d, JCP
) 11.8 Hz, i-C6H5),131.7 (br, m-C6H5), 131.2 (br, p-C6H5), 129.2
(d, 2JCP ) 9.8 Hz, o-C6H5), 103.2 (br, R-C5H4), 101.3 (br, ꢀ-C5H4),
88.3 (s, C7H7). 31P{1H} NMR (121 MHz, dichloromethane-d2) δ
19.5 (br, PPh2).
Synthesis of [(η7-C7H7)Ti(η5-C5H4PPh2)] (3). A solution chlo-
rodiphenylphosphane (0.2 mL, 1.1 mmol) in diethyl ether (5 mL)
was added slowly to a suspension of monolithiotroticcene 5 (0.35
g, 0.91 mmol) in 20 mL of hexane at -78 °C. The mixture was
warmed to room temperature and stirred overnight, whereby it
slowly changed from a green suspension to a light green solution.
The filtrate was dried under vacuum and the solid was washed with
two small portions of cold hexane (2 × 3 mL). The residue was
dried under vacuum affording a light green solid (0.29 mg, 84%
yield). 1H NMR (200 MHz, chloroform-d1): δ 7.36-7.11 (m, 10H,
Synthesis of cis-[(1)PtCl2] (9). To a dichloromethane (10 mL)
solution of 1 (141 mg, 0.246 mmol) was added a solution of trans-
Pt(SEt2)2Cl2 (110 mg, 0.246 mmol) in 5 mL of dichloromethane
via syringe at room temperature. The solution, which gradually
changed from a light blue-green to green color, was allowed to stir
overnight. The solvent was removed under reduced pressure and
the residue was washed with toluene and then with hexane. Drying
under vacuum afforded a green solid (180 mg, 87% yield). Suitable
crystals for X-ray analysis could be obtained by slow diffusion of
hexane into a dichloromethane solution of 9 at -30 °C. Elemental
analysis (%) calcd for C36H30Cl2P2PtTi: C, 51.57; H, 3.61. Found:
PC6H5), 5.44 (s, 7H C7H7), 5.37 (t, 2H, C5H4), 5.15 (t, 2H, C5H4).
1
13C{1H} NMR (50.3 MHz, chloroform-d1): δ 139.4 (d, JC-P
)
2
10.4 Hz, i-C6H5), 133.7 (d, JC-P ) 20.1 Hz, o-C6H5), 128.9 (s,
p-C6H5), 128.4 (d, 2JC-P ) 6.8 Hz, m-C6H5), 108.4 (d, 1JC-P ) 9.5
C, 51.93; H, 3.84. H NMR (400 MHz, dichloromethane-d2): δ
1
Hz, i-C5H4), 102.7 (d, 2JC-P ) 13.7 Hz, R-C5H4), 99.9 (d, 3JC-P
)
7.85-7.13 (m, 20H, P(C6H5)2), 5.91 (m, 2H, R7H6), 5.81 (m, 2H,
ꢀ-C7H6), 5.62 (m, 2H, γ-C7H6), 5.16 (m, 2H, ꢀ-C5H4), 4.87 (m,
2H, R-C5H4). 13C{1H} NMR (100 MHz, dichloromethane-d2): δ
4.0 Hz, ꢀ-C5H4), 87.2 (s, C7H6). 31P{1H} NMR (81 MHz, chloroform-
d1): δ -17.5 (s, C5H4PPh2). Full analytical data of this compound
were published recently.18
2
2
136.2 (d, JC-P ) 10.9 Hz, o-C6H5), 134.8 (d, JC-P ) 10.9 Hz,
4
Synthesis of [(3)Mo(CO)5] (6). A total of 200 mg (0.52 mmol)
of 3 and 1 equiv (136 mg, 0.52 mmol) of [Mo(CO)6] were placed
in a Schlenk tube with 15 mL of toluene and 5 mL of thf. The
reaction mixture was heated to reflux for 2 h. After filtration through
a plug of Celite, the solvent was removed in high vacuum. The
green residue was washed with hexane and dried in high vacuum,
yielding 82 mg (0.13 mmol, 24%) of 6. Suitable crystals for X-ray
diffraction analysis were obtained by cooling a saturated thf solution
of 6 to -30 °C. Anal. Calcd for C29H21MoO5PTi: C, 55.80; H,
3.39. Found: C, 56.81; H, 3.66. 1H NMR (200 MHz, benzene-d6):
δ 7.45 (m, 4H, o-C6H5); 7.05 (m, 6H, C6H5); 5.40 (s, 7H, C7H7);
5.41 (m, 2H, ꢀ-C5H4), 5.12 (m, 2H, R-C5H4). 13C{1H} NMR (50
o-C6H5), 131.6 (1JC-P ) 65.0 Hz, i-C6H5), 131.4 (d, JC-P ) 2.3
Hz, p-C6H5), 131.3 (1JC-P ) 67.3 Hz, i-C6H5), 131.2 (d, JC-P
)
4
3
2.3 Hz, p-C6H5), 128.2 (d, JC-P ) 12.0 Hz, m-C6H5), 127.8 (d,
3JC-P ) 11.6 Hz, m-C6H5), 104.8 (d, JC-P ) 9.3 Hz, R-C5H4),
2
2
102.5 (d, JC-P ) 7.9 Hz, ꢀ-C5H4), 93.3 (d, JC-P ) 14.2 Hz,
ꢀ-C7H6), 90.5 (s, γ-C7H6), 89.7 (d, JC-P ) 13.8 Hz, R-C7H6).
31P{1H} NMR (162 MHz, dichloromethane-d2): δ 38.3 (m, JP-P
2
1
2
) 13.4 Hz, JP-Pt ) 3812 Hz, C7H6PPh2), 10.5 (d, JP-P ) 13.4
1
Hz, C5H4PPh2, JP-Pt ) 3780 Hz).
Synthesis of trans-[(2)2PtCl2] (10). A solution of 2 (135 mg,
0.347 mmol) dissolved in 10 mL of dichloromethane was added
dropwise to a solution of trans-Pt(SEt2)2Cl2 (76.5 mg, 0.171 mmol)
in dichloromethane (5 mL). The reaction mixture was allowed to
stir overnight at room temperature, during which time a light blue-
green solid precipitated out. The supernatant liquid was decanted
from the green solid. Drying the residue under vacuum afforded
light green solid 10 (147 mg, 81% yield). Suitable crystals for X-ray
analysis could be obtained by cooling a saturated solution of 10 in
dichloromethane to -30 °C. Elemental analysis (%) calcd for
C48H42Cl2P2PtTi2: C, 55.30; H, 4.06. Found: C, 54.57; H, 4.25. 1H
NMR (600 MHz, dichloromethane-d2): δ 7.90-7.12 (m, 10H,
P(C6H5)4), 5.89 (m, 2H, C7H6), 5.70 (m, 4H, C7H6), 5.43 (s, 5H,
C5H5). 13C{1H} NMR (150.9 MHz, dichloromethane-d2): δ 135.3
(m, i-C6H5), 129.3 (m, o-C6H5), 128.5 (m, p-C6H5), 125.6 (m,
m-C6H5), 101.8 (m, γ-C7H6), 100.4 (s, C5H5), 99.9 (m, ꢀ-C7H6),
98.8 (m, R-C7H6), 87.1 (m, i-C7H6).31P{1H} NMR (81 MHz,
1
MHz, benzene-d6): δ 206.8 (s, CO), 206.6 (s, CO), 139.9 (d, JCP
) 38.3 Hz, i-C6H5), 133.1 (d, 2JC-P ) 12.6 Hz, o-C6H5), 130.8 (s,
3
p-C6H5), 128.8 (d, JCP ) 1.5 Hz, m-C6H5), 108.0 (d,1JCP ) 37.5
2
Hz, i-C5H4), 104.5 (d, JC-P ) 11.4 Hz, R-C5H4), 100.5 (3JC-P
)
7.6 Hz, ꢀ-C5H4), 88.4 (s, C7H7). 31P{1H} NMR (81 MHz, benzene-
d6): δ 23.0 (s, PPh2). IR(ATR): 2069, 1981, 1934, 1917 cm-1 (υ
(CO)).
Synthesis of [(3)AuCl] (7). A total of 165 mg (0.51 mmol) of
[(tht)AuCl] was dissolved in the least amount of CH2Cl2 and cooled
to -78 °C. One equivalent of 3 (200 mg, 0.56 mmol) was dissolved
in 10 mL of CH2Cl2, transferred into a dropping funnel, cooled to
-30 °C and slowly added to the Au(I) solution. The reaction
mixture was allowed to warm to room temperature overnight and
filtered through a plug of Celite followed by removal of the solvent.
The green, oily residue was washed with hexane until it became a
green solid. Compound 7 was obtained in moderate yields (97 mg,
0.16 mmol, 31%) and a suitable crystal for X-ray diffraction analysis
was obtained by slow diffusion of pentane into a saturated solution
of 7 in thf at -30 °C. Anal. Calcd for C24H21AuClPTi: C, 46.44;
1
dichloromethane-d2): δ 31.4 (s, PPh2C7, JPt-P ) 2652 Hz).
Synthesis of trans-[(3)2PtCl2] (11). A solution of 3 (120.3 mg,
0.310 mmol) dissolved in 10 mL of toluene was added dropwise
to a solution of trans-Pt(SEt2)2Cl2 (69 mg, 0.154 mmol) in toluene
(5 mL). The reaction mixture was allowed to stir for 5 h at room
temperature, during which time a dark green suspension had formed.
The solvent was dried under reduced pressure and the residue was
dissolved in dichloromethane and kept at -30 °C. After 8 h, a green
1
H 3.41. Found: C, 47.07; H, 3.89. H NMR (200 MHz, benzene-
d6): δ 7.21 (m, 4H, o-C6H5), 6.87 (br m, 6H, C6H5), 5.46 (s, 7H,
C7H7), 4.86 (m, 4H, C5H4). 13C (100 MHz, dichloromethane-d2): δ
9
17022 J. AM. CHEM. SOC. VOL. 131, NO. 46, 2009

Selective Functionalization of Troticene
A R T I C L E S
formed solid, suitable for X-ray analysis, had crystallized. Drying
under vacuum afforded 124 mg of 11 (77% yield). Elemental
analysis (%) calcd for C50H46Cl6P2PtTi2: C, 49.53; H, 3.82. Found:
C, 51.47; H, 4.72 (the values may be attributed to partial loss of
dichloromethane from the crystalline sample). 1H NMR (600 MHz,
dichloromethane-d2): δ 7.80-7.03 (m, 10H, P(C6H5)4), 5.70 (s, 7H,
C7H7), 5.60 (m, 2H, C5H4), 5.46 (m, 2H, C5H4). 13C{1H} NMR
(150.9 MHz, dichloromethane-d2): δ 134.4 (m, i-C6H5), 131.2 (m,
o-C6H5), 128.5 (m, p-C6H5), 125.5 (m, m-C6H5), 105.6 (m, i-C5H4),
103.3 (m, R-C5H4), 100.4 (m, ꢀ-C5H4), 88.3 (s, C7H7). 31P{1H}
a riding model. Numerical details are summarized in Table 1.
Special features and exceptions: for compounds 4-6, 8 and 11, H
atoms of the rings were refined freely but with C-H distances
constrained equally. For compounds 5, 7, and 9, which crystallize
by chance in noncentrosymmetric space groups, the Flack parameter
refined to 0.379(5) (racemic twin), 0.016(15), and 0.005(5),
respectively. The two dichloromethane molecules of structure 10
are both disordered (one over an inversion center). The crystal of
compound 7 was twinned, but the closeness of ꢀ to 90° prevented
successful untwinning despite repeated efforts. For this reason, the
R values and residual electron density are unsatisfactory.
1
NMR (161.9 MHz, dichloromethane-d2): δ 6.7 (s, PPh2C5, JPt-P
) 2634 Hz).
Acknowledgment. This work was supported by the Deutsche
Forschungsgemeinschaft (DFG) through grant Ta 189/5-3.
X-ray Crystal Structure Determinations. Data were recorded
on area detectors (Oxford Diffraction) at low temperature. Absorp-
tion corrections were performed on the basis of multiscans.
Structures were refined anisotropically using the program SHELXL-
97.52 Hydrogen atoms were included using rigid methyl groups or
Supporting Information Available: CIF files for each of the
crystal structures. This material is available free of charge via
the Internet at http://pubs.acs.org.
(52) Sheldrick, G. M. Acta Crystallogr. 2008, A64, 112.
JA9080056
9
J. AM. CHEM. SOC. VOL. 131, NO. 46, 2009 17023