Synthesis and reactivity of rhodium mono-and bis(diolefin) complexes. Characterization of intermediates in the rhodium-catalyzed cyclotetramerization of butadiene

Article abstract of DOI:10.1021/om100554d

Rhodium bis(diolefin) complexes of the general composition [Rh(η⁴-diene)₂(L)]X (diene = butadiene, isoprene, 2,3-dimethylbutadiene; L = PiPr₃, PCy₃, PtBu ₂Me, AsiPr₃, SbiPr₃, CO,

Full text of DOI:10.1021/om100554d

5646 Organometallics 2010, 29, 5646–5660
DOI: 10.1021/om100554d
Synthesis and Reactivity of Rhodium Mono- and Bis(diolefin) Complexes.
Characterization of Intermediates in the Rhodium-Catalyzed
Cyclotetramerization of Butadiene†
Marco Bosch‡ and Helmut Werner*
€
Institut fu€r Anorganische Chemie der Universitat Wurzburg, Am Hubland, D-97074 Wurzburg, Germany.
€
€
‡Present address: BASF Antwerpen N.V., PC/A, B-2040 Antwerp, Belgium.
Received June 4, 2010
Rhodium bis(diolefin) complexes of the general composition [Rh(η4-diene)2(L)]X (diene = buta-
diene, isoprene, 2,3-dimethylbutadiene; L = PiPr3, PCy3, PtBu2Me, AsiPr3, SbiPr3, CO, CNtBu,
CN-2,6-C6H3iPr2; X = CF3SO3, B(Arf)4) were prepared from the nonionic compounds [Rh-
{μ-O2S(O)CF3}(η2-C8H14)2]2 (1) and [Rh{κ1-OS(O)2CF3}(η4-diene)2] (2-4) as precursors. The
reaction of 1 with 1,3-cyclohexadiene led to the formation of [(η6-C6H6)Rh(η4-C6H8)]CF3SO3,
whereas from 1 and 6,60-dimethylfulvene the unsymmetrical sandwich compound [{η5-C5H4CH-
(CH3)2}Rh{η5-C5H4C(dCH2)CH3}]CF3SO3 was obtained. From [Rh{κ2-O2S(O)CF3}(PiPr3)2] and
1,3-cyclohexadiene or 6,60-dimethylfulvene the four-coordinated diene complexes [Rh(η4-diene)-
(PiPr3)2]CF3SO3 were prepared, the cyclohexadiene derivative of which slowly rearranged at room
temperature to cis,cis,trans-[Rh{κ2-O2S(O)CF3}(H)2(PiPr3)2] and benzene. Similarly, [Rh(η4-
C6H8){κ2-iPr2P(CH2)3PiPr2}]CF3SO3, obtained from [Rh(η4-C4H6){κ2-iPr2P(CH2)3PiPr2}]CF3SO3
and 1,3-cyclohexadiene, rearranged at 50 °C to [(η6-C6H6)Rh{κ2-iPr2P(CH2)3PiPr2}]CF3SO3. The
bis(butadiene) complexes [Rh(η4-C4H6)2(PR3)]CF3SO3 (R = iPr, Cy) reacted in CH2Cl2 at ambient
temperature to afford the neutral C-C coupling products [Rh(η3:η3-C8H12){κ1-OS(O)2CF3}(PR3)],
which upon treatment with NaB(Arf)4 gave the ionic compounds [Rh(η3:η3-C8H12)(PR3)]B(Arf)4.
The two isomers [Rh(η4-C4H6)2(PR3)]CF3SO3 and [Rh(η3:η3-C8H12){κ1-OS(O)2CF3}(PR3)] are
likely intermediates in the (cyclo)oligo- and polymerization of butadiene catalyzed by 1/PR3. While
the oligomeric fraction predominantly consists of C12 and C16 olefinic hydrocarbons, the main
component among the C16 tetramers is cis,cis,trans,trans-1,5,9,13-cyclohexadecatetraene.
Introduction
cyclotetramerization has received little attention in the liter-
ature. The obvious reason is that in contrast to the cyclotri-
merization, which was intensively investigated by Wilke and
others,5,6 to the best of our knowledge no efficient and selec-
tive catalyst for the formation of the cyclotetramer has been
discovered. Several attempts, mainly undertaken by research
groups in the perfume and fragrance industry,7 to develop an
appropriate catalytic system remained unsuccessful.
In the context of our work on the use of rhodium(I)
sulfonato compounds to catalyze C-C coupling reactions
of olefins with diphenyldiazomethane,8a we recently repor-
ted that the four-coordinated rhodium(I) triflate [Rh{κ2-
O2S(O)CF3}(PiPr3)2] catalyzes not only the di- and oligo-
merization of ethene but also the polymerization of
butadiene.8b,c An unexpected side product of this process
was 1,5,9,13-cyclohexadecatetraene. Although in the initial
studies the yield of this cyclotetramer was rather low, we
Despite the plethora of studies about the transition-
metal-catalyzed oligo- and polymerization of butadiene,1-4
†Part of the Dietmar Seyferth Festschrift. Dedicated to Professor Dietmar
Seyferth in recognition of his scientific achievements and his prominent role
as chief editor of Organometallics.
(1) (a) Wilke, G. Angew. Chem. 1963, 75, 10-20; Angew. Chem., Int.
Ed. Engl. 1963, 2, 105-115. (b) Jolly, P. W.; Wilke, G. The Organic
Chemistry of Nickel; Academic Press: New York, 1975; Vol. 2, pp
133-212. (c) Jolly, P. W. In Comprehensive Organometallic Chemistry;
Wilkinson, G., Stone, F. G. A., Abel, E. W., Eds.; Pergamon: New York,
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1982; Vol. 8, pp 671-711. (d) Keim, W.; Behr, A.; Roper, M. In
Comprehensive Organometallic Chemistry; Wilkinson, G., Stone,
F. G. A., Abel, E. W., Eds.; Pergamon: New York, 1982; Vol. 8, pp
371-462. (e) Wilke, G.; Eckerle, A. In Applied Homogeneous Catalysis
with Organometallic Compounds; Cornils, B., Herrmann, W. A., Eds.;
VCH: Weinheim, Germany, 2002; Vol. 1, pp 362-380.
(2) Porri, L.; Natta, G.; Gallazzi, M. C. J. Polym. Sci., C 1967, 16,
2525–2537.
(3) Tsuji, J. Adv. Organomet. Chem. 1979, 17, 141–193.
(4) Taube, R.; Sylvester, G. In Applied Homogeneous Catalysis with
Organometallic Compounds; Cornils, B., Herrmann, W. A., Eds.; VCH:
Weinheim, Germany, 2002; Vol. 1, pp 362-380.
(6) (a) Polacek, J.; Antropiusova, H.; Hanus, V.; Petrusova, L.;
Mach, K. J. Mol. Catal. 1985, 29, 165–180. (b) Polacek, J.; Antropiusova,
H.; Petrusova, L.; Mach, K. J. Mol. Catal. 1990, 58, 53–73. (c) Spencer,
M. D.; Wilson, S. R.; Girolami, G. S. Organometallics 1997, 16, 3055–3067.
(7) Ohloff, G. Personal communication, 1992.
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(5) (a) Breil, H.; Heimbach, P.; Kroner, M.; Muller, H.; Wilke, G.
Makromol. Chem. 1963, 69, 18–40. (b) Wilke, G.; Bogdanovic, B.; Hardt,
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P.; Heimbach, P.; Keim, W.; Kroner, M.; Oberkirch, W.; Tanaka, K.;
(8) (a) Werner, H.; Bosch, M.; Hahn, C.; Kukla, F.; Laubender, M.;
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Steinr€ucke, E.; Walter, D.; Zimmermann, H. Angew. Chem. 1966, 78,
157-172; Angew. Chem., Int. Ed. Engl. 1966, 5, 151-164. (c) Wilke, G.
Angew. Chem. 1988, 100, 189-211; Angew. Chem., Int. Ed. Engl. 1988,
27, 185-206.
Manger, M.; Schneider, M. E.; Weberndorfer, B.; Windmuller, B.
J. Chem. Soc., Dalton Trans. 1998, 3549–3558. (b) Schneider, M. E.
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Dissertation, Universitat W€urzburg, 1997. (c) Mohring, U. Dissertation,
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r
2010 American Chemical Society
pubs.acs.org/Organometallics
Published on Web 08/10/2010

Article
Organometallics, Vol. 29, No. 21, 2010 5647
Scheme 1
Scheme 2
the ionic complexes 5a, 6a, and 7 were obtained and isolated
as colorless solids in almost quantitative yield. Salt meta-
thesis of 5a and 6a with NaB(Arf)4 gave the corresponding
tetraaryloborates 5b and 6b, which in solution are somewhat
1
less labile than the triflate counterparts. The H and 13C
NMR spectra of 5a,b, 6a,b, and 7 display only one set of
signals for the proton and carbon atoms of the two butadiene
units, which indicates a symmetric orientation of these
ligands around the metal. In the case of 5a, the s-cis disposi-
tion of the dienes was confirmed by an X-ray structure
analysis.11
The reaction of 2 with 1 equiv of PPh3 led to the formation
of 8, which was characterized by 1H, 13C, 19F, and 31P NMR
spectroscopy. The data are almost identical with those of the
perchlorate [Rh(s-cis-η4-C4H6)2(PPh3)]ClO4, previously pre-
pared by Schrock and Osborn from [Rh(η4-nor-C7H8)-
(PPh3)2]ClO4 and butadiene.12 The reaction of 2 with PMe3
in the ratio of 1:1 in dichloromethane afforded a mixture of
products among which, apart from the starting material, the
cations [Rh(η4-C4H6)2(PMe3)]þ and [Rh(η4-C4H6)(PMe3)3]þ
could be identified by spectroscopic means.13 The more bulky
phosphine PtBu2Ph, which according to Tolman has the
same cone angle as PCy3,14 reacted with 2 to give the un-
charged complex 9, isolated as an orange, slightly air-sensi-
tive solid in 94% yield. In the 1H NMR spectrum of 9 only
three resonances for the butadiene protons appear, which is
noteworthy insofar as, owing to the Cs symmetry of the
molecule, six signals would be expected. As the 13C NMR
spectrum of 9 also shows only two resonances for the C4H6
carbon atoms, we assume that in solution the butadiene
ligand rotates around the diene-rhodium axis, the rotation
being fast on the NMR time scale.
attempted to find out whether there could be a relationship
regarding the mechanism of the rhodium-catalyzed cyclote-
tramerization and the nickel-catalyzed cyclotrimerization
and polymerization of butadiene, the latter being quite well
understood.1,2,4-6,9
In this article we disclose the preparation of a series of
rhodium bis(diolefin) complexes of the general composition
[Rh(η4-diene)2(L)]X (diene = butadiene, isoprene, 2,3-di-
methylbutadiene; L = PR3, AsiPr3, SbiPr3, CO, CNR; X =
CF3SO3, B(Arf)4) and, for diene = butadiene and PR3 =
PiPr3, PCy3, its C-C coupling products [Rh{η3:η3-C8H12)-
(PR3)]X. Several rhodium(I) mono(butadiene) and mono-
(cyclohexadiene) as well as some benzene, cyclopentadienyl,
and π-allyl compounds were also prepared. Finally, the role
of the bis(butadiene) complexes and the η3:η3-C8H12 C-C
coupling products as intermediates in the cyclotetrameriza-
tion reaction will be discussed. Some preliminary results have
already been communicated.10
The starting material 1 reacts not only with butadiene and
its relatives but also with 1,3-cyclohexadiene. The product of
this reaction, however, is not an analogue of 2 but the
benzene rhodium(I) complex 10 (Scheme 2). It is a red-brown
solid, the molar conductivity of which in nitromethane cor-
responds to that of an 1:1 electrolyte. The 1H and 13C NMR
spectra of 10 display the same set of signals for the benzene
and diene protons as was found for the uncharged complexes
[(η6-C6H6)Fe(η4-C6H8)] and [(η6-C6H6)Ru(η4-C6H8)],
respectively.15 Regarding the formation of 10, we assume
that initially either the uncharged compound [Rh{κ1-OS-
(O)2CF3})(η4-C6H8)2] or the triflate of the 16-electron spe-
cies [Rh(η4-C6H8)2]þ is formed, which in several steps rear-
ranges, possibly via [(η5-C6H7)RhH(η4-C6H8)]þ and [(η6-
C6H6)RhH(η3-C6H9)]þ, to the product. The loss of H2 seems
to be supported by the presence of free diene, which is
Results and Discussion
1. Preparation of Rhodium(I) Mono- and Bis(diolefin)
Complexes from [Rh{μ-O2S(O)CF3}(η2-C8H14)2]2 and [Rh-
{K1-OS(O)2CF3}(s-cis-η4-C4H6)2] as the Precursors. In the
context of our studies to elucidate the structure of supposed
intermediates in the rhodium-catalyzed oligo- and polymer-
ization of butadiene, we recently reacted the dimeric triflate-
bridged cyclooctene rhodium(I) complex 1 with excess buta-
diene and isolated the five-coordinated product 2 (Scheme 1).
The structure of the corresponding isoprene derivative 3
(prepared under the same conditions as 2 and 4) was deter-
mined by X-ray crystallography.11 Taking into account that
the addition of 1 equiv of tricyclohexylphosphine to the
nickel(0) compound [Ni(s-cis-η4-C4H4Me2)2] induces the
coupling of the two ligated 2,3-dimethylbutadiene ligands,
we similarly treated compound 2 with PCy3, PiPr3, and
PtBu2Me. In acetone or dichloromethane at room temperature,
(12) (a) Schrock, R. R.; Osborn, J. A. J. Am. Chem. Soc. 1971, 93,
2397–2407. (b) Schrock, R. R.; Osborn, J. A. J. Am. Chem. Soc. 1975, 98,
4450–4455.
(13) Kovalev, I. P.; Kolmogorov, Y. N.; Strelenko, Y. A.; Ignatenko,
A. V.; Vinogradov, M. G.; Nikishin, G. I. J. Organomet. Chem. 1990,
385, 173–185.
(9) (a) Tobisch, S.; Taube, R. Organometallics 1999, 18, 5204–5218.
(b) Tobisch, S. Acc. Chem. Res. 2002, 35, 96–104. (c) Tobisch, S.; Taube, R.
Organometallics 2008, 27, 2159–2162.
(14) Tolman, C. A. Chem. Rev. 1977, 77, 313–348.
€
(10) Bosch, M.; Brookhart, M. S.; Ilg, K.; Werner, H. Angew. Chem.
(15) (a) Fischer, E. O.; Muller, J. Z. Naturforsch., B 1962, 17, 776–
2000, 112, 2388-2391; Angew. Chem., Int. Ed. 2000, 39, 2304-2307.
777. (b) Ittel, S. D.; Van Catledge, F. A.; Jesson, J. P. J. Am. Chem. Soc.
1979, 101, 3874–3884. (c) Pertici, P.; Vitulli, G.; Paci, M.; Porri, L. J. Chem.
Soc., Dalton Trans. 1980, 1961–1964.
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(11) Bosch, M.; Laubender, M.; Weberndorfer, B.; Werner, H. Chem.
Eur. J. 1999, 5, 2203–2211.

5648 Organometallics, Vol. 29, No. 21, 2010
Bosch and Werner
consistent with the observation that by using only 2 equiv of
1,3-C6H8 the yield of 10 is less than 50%. With excess diene,
the yield of the isolated complex was 78%. Previously, it was
mentioned that the reaction of [Rh(μ-Cl)(η4-C6H8)]2 with
AgBF4 in the presence of 1,3-cyclohexadiene gave [(η6-
C6H6)Rh(η4-C6H8)]BF4,16 but no analytical or spectrosco-
pical data for this compound were given.
Scheme 3
Under the same conditions as used for the preparation of
10, the cyclooctene derivative 1 also reacted with 6,6-dimet-
hylfulvene, affording exclusively the unsymmetrical sand-
wich complex 11. It is a colorless air-stable solid, the properties
of which resemble those of the rhodocenium salts [Rh(η5-
1
C5H5)2]X.17 Characteristic features in the H NMR spec-
trum of 11 are two signals for the exocyclic methylene protons
at δ 5.58 and 5.30 and a resonance for the C(dCH2)CH3
methyl protons at δ 2.00. The 13C NMR spectrum of 11
displays six signals for the cyclopentadienyl carbon atoms,
which are split into doublets with a 103Rh,13C coupling con-
stant of 7.1 Hz. The two methylene carbon atoms resonate at
δ 133.5 and 119.2 Hz, and the C(dCH2)CH3 carbon atom
resonates at δ 21.1 Hz. These data perfectly agree with those
of the uncharged complex [{η5-C5H4C(dCH2)CH3}Rh(η4-
nor-C7H8)].18 Since the reaction of 1 with 6,6-dimethylful-
vene does not lead to the symmetrical sandwich complex
[Rh{η5-C5H4CH(CH3)2}2]CF3SO3, which would be expected
if the exocyclic C(CH3)2 fragment of the fulvene is converted to
the CH(CH3)2 unit by hydrogen abstraction from the
solvent,19 we assume that an intramolecular hydrogen transfer
from one methyl group of an initially coordinated η4-C5H4-
C(CH3)2 ligand to a second dimethylfulvene moiety occurs.
The 16-electron cation [Rh{η4-C5H4C(CH3)2}2]þ could be an
intermediate in this process.
compound 13 could not be converted into the coordinatively
saturated 18-electron cation [Rh(η4-C6H8)2(PiPr3)]þ.
The reactions of either 13 with 1 equiv of PiPr3 or of 14
(prepared from [Rh(η3-C3H5)(PiPr3)2] and CF3SO3H)8a with
excess 1,3-cyclohexadiene afforded the four-coordinated
bis(phosphine) complex 15 as a red, slightly air-sensitive
1
solid in 80-85% yield. As for 13, the H NMR spectrum
of 15 displays four resonances for the diene protons at δ 5.29,
4.98, 1.76, and 1.10, and the 31P NMR spectrum shows a
doublet at δ 41.2 with the rather large 103Rh,31P coupling
constant of 170.3 Hz. Solutions of 15 in CH2Cl2 or CD2Cl2
are somewhat labile, and if they are stored at room tempera-
ture, a smooth change of color from red to yellow occurs.
After 24 h, the 1H NMR signals of 15 disappear and those of
the rhodium(III) dihydrido compound 17 and free benzene
are observed. The intensities of the signals of 17 and C6H6
correspond to a ratio of 1:1. The rhodium(III) dihydrido
compound 17 was previously prepared in our laboratory
from 14 and H2.8a
With the aim to prepare the rhodium(I) complex [Rh(η4-
C6H8)2(PiPr3)]CF3SO3 as an analogue of 5a with 1,3-cyclo-
hexadiene as diene ligands, we treated the four-coordinated
precursor 12, generated in situ from 1 and PiPr3,8a with
excess 1,3-C6H8 but isolated the uncharged mono(diene)
compound 13 in virtually quantitative yield (Scheme 3).
The IR spectrum of the orange, only moderately air-sensitive
solid shows for the asymmetric OSO stretching mode an
absorption at 1317 cm-1, which is consistent with the pre-
sence of a monodentate triflate ligand.20 In analogy to 9, the
1H NMR spectrum of 13 displays only four resonances for
the C6H8 protons at δ 5.11, 4.38, 1.88,and 0.94, whereas due
to the Cs symmetry of the molecule eight signals would be
expected. Assuming that a fast rotation of the 1,3-C6H8
ligand around the diene-rhodium axis occurs at room
The uncharged chelate complex 14 also reacts in dichloro-
methane with 6,6-dimethylfulvene to yield the ionic com-
pound 16. The 13C NMR spectrum of the cation displays
four resonances at δ 130.5, 130.4, 91.9, and 77.3 for the
fulvene sp2 carbon atoms, of which only that for the C(CH3)2
carbon does not show a 103Rh,13C coupling.21 Therefore, it
seems that the exocyclic CdC bond is not, or is only slightly,
involved in the coordination to the metal and that a η5- or η6-
bonding mode of the C5H4C(CH3)2 unit is of minor impor-
tance. In solutions of acetone or CH2Cl2 compound 16 is
unstable, but in contrast to 15 it does not rearrange to a
definite product; it produces a rhodium mirror instead.
The bis(butadiene) complex 2 (which with 1 equiv of PiPr3
affords 5a) reacts with PiPr3 in the ratio of 1:3 to give the
crystallographically characterized rhodium(I) compound
[Rh{η3-anti-(iPr3PCH2)CHCHCH2}(PiPr3)2]CF3SO3.11
1
temperature, we measured the H NMR spectrum of 13 in
CD2Cl2 in a lower temperature range. At 183 K, each
resonance of the olefinic protons is split into two slightly
broadened singlets at δ 5.66 and 4.37 and δ 5.04 and 3.39,
respectively. This is in agreement with our assumption. We
note that even with a 10-fold excess of 1,3-cyclohexadiene
(16) Draggett, P. T.; Green, M.; Lowrie, S. F. W. J. Organomet.
Chem. 1977, 135, C60–C62.
(17) (a) Cotton, F. A.; Whipple, R. O.; Wilkinson, G. J. Am. Chem.
Soc. 1953, 75, 3586–3587. (b) Angelici, R. J.; Fischer, E. O. J. Am. Chem.
Soc. 1963, 85, 3733–3735.
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(18) Muller, J.; Stock, R.; Pickardt, J. Z. Naturforsch., B 1983, 38,
1454–1459.
(19) Teuber, R.; Koppe, R.; Linti, G.; Tacke, M. J. Organomet.
Chem. 1997, 545, 105–110.
(20) (a) Lawrance, G. A. Chem. Rev. 1986, 86, 17–33. (b) Thewissen,
M. W.; Marsman, J. W. Recl. Trav. Chem. Pays-Bas 1988, 107, 248–255.
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(21) (a) The other NMR data for the fulvene ligand of 15 correspond
to those of the related complex [Rh(η4-C5H4CPh2){P(OPh)3}2]ClO4.21b
(b) Jeffery, J.; Mawby, R. J.; Hursthouse, M. B.; Walker, N. P. C.
J. Chem. Soc., Chem. Commun. 1982, 1411–1412.

Article
Organometallics, Vol. 29, No. 21, 2010 5649
Scheme 4
Scheme 5
Under similar conditions, the reaction of 2 with PCy3 in
acetone results in the formation of the corresponding η3-
allylphosphonium derivative 18. The proposed structure (see
Scheme 4) is supported in particular by the 31P NMR spec-
trum, which displays a doublet of doublet of doublets at δ
41.5 for the metal-bound phosphine in a position cis to the
substituted η3-allyl carbon atom and a doublet of doublets at
δ 37.0 for the second metal-bound phosphine. Both signals
exhibit a large 103Rh,31P coupling constant of, respectively,
181.7 and 186.1 Hz. The resonance for the carbon-linked 31P
nuclei appears as a doublet at δ 20.9 and shows a rather small
31P,31P coupling constant of 11.5 Hz. The 1H and 13C NMR
data for the allylphosphonium ligand of 18 correspond to
those of the triisopropylphosphine analogue. In contrast to
PCy3, triphenylphosphine reacts with 2 to yield not an
analogue of 18 but rather the mono(diene) complex
[Rh(η4-C4H6)(PPh3)2]CF3SO3.12b Treatment of this com-
pound with excess PPh3 led to [Rh(PPh3)3]CF3SO3, which
is also well-known.22
range of 1310-1300 cm-1, where an asymmetric OSO
stretching mode for a coordinated triflate would be expected.
The 1H and 13C NMR data for the C8H12 ligand of 19 and 20
are quite similar to those of other transition-metal η3:η3-
octa-2,6-diene-1,8-diyl and η3:η3-2,7-dimethylocta-2,6-diene-
1,8-diyl complexes, such as [(η5-C5H5)Mo(η3:η3-C8H12)-
(L)]BF4 (L = CH3CN, PMe3),23 [Ni(η3:η3-C8H12)(PPh3)],24
[Ru(η3:η3-C8H10Me2)Cl(μ-Cl)]2,25 and [Ru(η3:η3-C8H10Me2)-
(PiPr3)Cl2].26 The NMR data of 19 and 20 confirm that only
one stereoisomer is formed, despite the fact that, in principle,
due to the syn and anti arrangement of the C2H4 bridge and
the exo and endo orientation of the η3-CHCHCH2 units of
the octadienediyl ligand, four diastereoisomers could be an-
ticipated. The syn-exo,endo structure, found in the crystal
for 19, exists also in solution and thus seems to be the
thermodynamically preferred species. The 1H NMR spectra
of 19 and 20 remain unchanged between -90 and 50 °C,
indicating that no isomerization occurs in this range of
temperature.
Not only 5a and 6a but also 5b and 6b react on heating
to afford the isomers 21 and 22 in good yields. The tetra-
aryolborates were also obtained from 19 and 20 and NaB(Arf)4
in dichloromethane. In comparison to 5a and 6a, the phos-
phine complexes 7 and 8 behave differently, and when solu-
tions of these compounds in CH2Cl2 or acetone were stirred
at room temperature or elevated temperatures, a mixture of
products was formed. An analogue of 19 or 20 could not be
detected by NMR spectroscopy. The bis(isoprene) and bis-
(2,3-dimethylbutadiene) complexes [Rh(s-cis-η4-C4H5Me)2-
(PiPr3)]O3SCF3 and [Rh(s-cis-η4-C4H4Me2)2(PiPr3)]O3SCF3,11
structurally related to 5a, undergo no isomerization when
stirred in nitromethane for 6 h at 40 °C and were recovered
unchanged.
2. Thermally Induced C-C Coupling Reactions of the
Phosphine Derivatives [Rh(s-cis-η4-C4H6)2(PR3)]X. As men-
tioned above, solutions of 5a and 6a are not stable for longer
periods of time and undergo a smooth change of color from
1
orange to deep red. Monitoring the change by H NMR
spectroscopy reveals a decrease in the intensity of the signals
for the butadiene protons and the appearance of six new re-
sonances between δ 5.23 and 1.53 in CD2Cl2. If the solutions
of 5a are stored for 3 days or those of 6a for 1 day at room
temperature, the signals of the starting materials disappear.
The rearrangement of 5a and 6a can be facilitated by heating
and in dichloromethane under reflux is completed in 12 h for
5a and in 6 h for 6a. After removal of the solvent and re-
crystallization of the residue from CH2Cl2/pentane, the red,
moderately air-stable solids 19 and 20 were isolated in ca.
75% yield. They can be stored without decomposition under
argon at 0 °C for several days. The elemental analyses of 19
and 20 confirm that they have the same composition as the
precursors 5a and 6a. An intramolecular C-C coupling of
the two butadiene units has obviously occurred, and an
η3:η3-octa-2,6-diene-1,8-diyl ligand is formed (Scheme 5).
For 19, the presence of this ligand as well as the coordina-
tion of the triflate anion to rhodium has been substantiated
by an X-ray structure analysis.10 Apart from the fact that one
terminal C3 fragment of the C8 chain is slightly distorted in
comparison to the other, the noteworthy structural feature is
that the Rh-O bond length of 19 is significantly longer (ca.
The kinetics for the conversion of 5a,b to 19 and 21 and of
1
6a,b to 20 and 22 were determined in CD3NO2 using H
NMR spectroscopy. In each case, the reactions follow a first-
order rate law. At 325 K, the tricyclohexylphosphine deri-
vatives 6a,b react slightly more quickly than the triisopro-
pylphosphine counterparts 5a,b; the difference in the free
energy of activation ΔGq is 1.1(5) kJ mol-1. The anions
CF3SO3- and B(Arf)4- have nearly no influence; i.e., in the
limit of errors the rate constants and the ΔGq values for the
˚
0.18 A) than in the bis(butadiene) complex 2. This could
explain the fact that solutions of both 19 and 20 in nitro-
methane reveal a molar conductivity of ca. 70-75 cm2 Ω-1
mol-1, corresponding to a 1:1 electrolyte. Moreover, the IR
spectra of 19 and 20 in CH2Cl2 show no absorptions in the
(22) (a) Legzdins, P.; Mitchell, R. W.; Rempel, G. L.; Ruddick, J. D.;
Wilkinson, G. J. Chem. Soc. A 1970, 3322–3326. (b) Yared, Y. W.; Miles,
S. L.; Bau, R.; Reed, C. A. J. Am. Chem. Soc. 1977, 99, 7076–7078.
(c) Siedle, A. R.; Newmark, R. A.; Pignolet, L. H.; Howells, R. D. J. Am.
Chem. Soc. 1984, 106, 1511–1512. (d) Pumblett, G.; Garner, C. D.; Clegg,
W. J. Chem. Soc., Dalton Trans. 1985, 1977–1980.
(23) Poli, R.; Wang, L.-S. J. Am. Chem. Soc. 1998, 120, 2831–2842.
€
(24) Benn, R.; Bussemeier, B.; Holle, S.; Jolly, P. W.; Mynott., R.;
Tkatchenko, I.; Wilke, G. J. Organomet. Chem. 1985, 279, 63–86.
(25) Cox, D. N.; Roulet, R. Inorg. Chem. 1990, 29, 1360–1365.
€
€
(26) Werner, H.; Stuer, W.; Jung, S.; Weberndorfer, B.; Wolf, J. Eur.
J. Inorg. Chem. 2002, 1076–1080.

5650 Organometallics, Vol. 29, No. 21, 2010
Bosch and Werner
Table 1. Activation Parameters for the Rearrangement of 5a to 19
and of 6a to 20
Scheme 6
ΔGq (kJ mol-1
)
ΔHq (kJ mol-1
)
ΔSq (J mol-1 K-1
)
5a f 19
6a f 20
99.9(5)
98.8(5)
100.4(5)
99.3(5)
1(2)
2(2)
reactions of 5a,b to 19 and 21 and of 6a,b to 20 and 22 are the
same.
The data for ΔHq and ΔSq, determined from the rate
constants for the rearrangement of 5a to 19 between 314.9
and 343.4 K and for the rearrangement of 6a to 20 between
317.5 and 333.2 K in nitromethane, are summarized in Table 1.
The values for ΔSq are almost zero, indicating that the C-C
coupling of the two butadiene ligands to generate the octa-
dienediyl unit occurs intramolecularly. Since there is nearly
no difference in ΔHq and ΔSq for the reactions of the PiPr3
complexes on one side and of the PCy3 analogues on the
other, one might assume that the initial step of the reactions
consists of the dissociation of the phosphine ligand. While
this could explain why the rate constants and the activation
parameters for the C-C coupling processes to give 19 and 20
are nearly identical, a detailed theoretical investigation of
alternative mechanistic paths for the formation of 19 led
to a different result.27 Using a gradient-corrected DFT
method, it is most likely that the favorable route for the
oxidative addition via C-C coupling starts from the pre-
valent 18-electron species [Rh(s-cis-η4-C4H6)2(PiPr3)]þ,
which under kinetic control initially affords the η3:η3-anti
isomer of the octadienediyl complex. The anti isomer con-
secutively transforms into the η3:η3-syn isomer 19, which is
the thermodynamically preferred species. It is worth noting
that the computationally predicted energy profile is in com-
plete agreement with the experimentally determined kinetic
data.
carbon atoms (Scheme 6). The orange-yellow solid is rather
air-sensitive and soluble in CH2Cl2, acetone, and diethyl
ether. It can be stored under argon at -10 °C for several days.
Each of the 12 protons and the 8 carbon atoms give rise to
1
distinct resonances in the H and 13C NMR spectra of 23,
and each of these resonances is split due to couplings with 1H,
13C, 31P, or 103Rh nuclei. The designation of the signals for
the protons of the phosphoniumoctadienyl moiety occurred
on the basis of COSY and 1H{31P} NMR spectra. The che-
mical shifts of the allylic protons are in good agreement with
those of [Rh{anti-η3-(iPr3PCH2)CHCHCH2}(PiPr3)2]CF3SO3
and other square-planar rhodium(I) η3-allyl compounds.11,28
A phosphoniumoctadienyl ligand similar to that found in 23
was recently generated at ruthenium by treatment of [RuCl2-
(η3:η3-C8H10Me2)(PF3)] with PCy3.26
Similar to the reaction of 5a to 19, the addition of excess
NaCl or KBr to solutions of 5a in acetone at room tempera-
ture resulted in a change of color from orange to red. How-
ever, instead of the octadienediyl derivatives [Rh(η3:η3-
C8H12)(PiPr3)X] (X = Cl, Br) the mono(butadiene) com-
plexes 24 and 25 were formed (Scheme 7). They are analogues
of 9 and 13 with the halide instead of the triflate coordinated
Solutions of 21 and 22 in nitromethane are stable for weeks
at room temperature. When the solutions are heated to 75 °C,
mixtures of products are formed. In the case of 21, the H
1
NMR spectrum showed after a short period of time a doublet
of triplets at δ -23.7, indicating the formation of a rhodium-
(III) dihydrido species similar to 17 (see Scheme 3). Contin-
uous heating led to the disappearance of this signal and the
resonances of 21 as well. After removal of the solvent, a GC
analysis of the oily residue revealed the presence of ethyl-
benzene and vinylcyclohexane as the main organic compo-
nents. If a solution of 21 in CD3NO2 was stirred under a
butadiene atmosphere for 3 h at 30 °C, apart from the
bis(butadiene) complex 5b, a mixture of 4-vinylcyclohexene,
1-ethylcyclohexene, ethylbenzene, and ethylidenecyclohex-
ane in the ratio of 6:1:4:1 was formed. We note that 4-vinyl-
cyclohexene is also the main product in the nickel(0)-
catalyzed dimerization of butadiene, which proceeds via a
nickel(II) η3:η3-octadienediyl intermediate.24 With regard to
the reaction of 21 with butadiene, we assume that the other
organic products (1-ethylcyclohexene, ethylbenzene, and
ethylidenecyclohexane) result from consecutive, rhodium-
catalyzed reactions of initially generated 4-vinylcyclohexene.
A rhodium(III) dihydrido species such as [RhH2(PiPr3)2-
(CH3NO2)2]þ could play a crucial role.
1
to rhodium(I). The H and 13C NMR spectra of 24 and 25
show in CD2Cl2, even at 243 K, broadened signals which in
analogy to 9 probably originate from a fast rotation of the
diene ligand around the butadiene-rhodium axis. The X-ray
structure analysis of 25 revealed a distorted-square-planar
coordination sphere with a Br-Rh-P bond angle of 93.4°.29
As in the case of [Rh{κ1-OS(O)2CF3}(η4-2,3-C4H4Me2)-
(PiPr3)],11 the diene ligand is linked unsymmetrically to the
metal, and the Rh-C distances trans to bromide are sig-
nificantly shorter than those trans to phosphorus. This
illustrates the different trans influences of bromide on one
side and PiPr3 on the other. The trans influence could also
explain why the C-C bond lengths of the two terminal
CHdCH2 fragments of the butadiene ligand in 25 differ by
1
˚
ca. 0.11 A, which is somewhat more than in [Rh{κ -OS-
(O)2CF3}(η4-2,3-C4H4Me2)(PiPr3)]. The Rh-Br and Rh-P
distances in 25 of, respectively, 2.471(1) and 2.306(1) A, agree
˚
quite well with those in related square-planar rhodium(I)
bromo and rhodium(I) triisopropylphosphine compounds.30,31
€
€
(28) (a) Werner, H.; Schafer, M.; Nurnberg, O.; Wolf, J. Chem. Ber.
1994, 127, 27–38. (b) Wiedemann, R.; Fleischer, R.; Stalke, D.; Werner, H.
Organometallics 1997, 16, 866–870.
The addition of 1 equiv of PiPr3 to a solution of 21 in
diethyl ether at 0 °C led to the formation of 23 by nucleo-
philic attack of the phosphine at one of the internal allylic
€
€
(29) Ilg, K. Dissertation, Universitat Wurzburg, 2001.
(30) (a) Jones, W. D.; Kuykendall, V. L. Inorg. Chem. 1991, 30, 2615–
2622. (b) Herrmann, W. A.; Goossen, L. J.; Spiegler, M. J. Organomet.
Chem. 1997, 547, 357–366.
(27) Tobisch, S.; Werner, H. Dalton Trans. 2004, 2963–2968.

Article
Organometallics, Vol. 29, No. 21, 2010 5651
Scheme 7
Scheme 9
Scheme 8
rather inert, and neither undergo a C-C coupling of the two
diene ligands nor react with excess AsiPr3 or SbiPr3 by
1
nucleophilic attack at the C4 moiety. In contrast to the H
and 13C NMR spectra of [Rh(cis-η4-C4H5Me)2(PiPr3)]-
O3SCF3, those of 27 and 30 indicate that not only the anti
isomer but mixtures of the anti and the syn isomers were
formed.32 For 27 the ratio of anti to syn was 91:9, and that for
30 was 86:14.
Passing a slow stream of CO through a solution of 2 in
acetone led, after evaporation of ca. 80% of the solvent and
addition of pentane, to the precipitation of a colorless solid
which by drying in vacuo transforms into a yellow oil. The IR
spectrum of the oil shows several CO stretching modes bet-
ween 2030 and 2160 cm-1, indicating that a mixture of
rhodium carbonyl compounds is present. This is supported
3. Rhodium(I) Mono- and Bis(diolefin) Complexes Con-
taining Ligands Other Than PiPr3 and PCy3. In attempting to
find out whether the replacement of PiPr3 by ligands that are
different in size and σ-donor/π-acceptor properties affects
the C-C coupling of the two butadiene ligands, a series of
compounds of the general composition [Rh(cis-η4-C4H6)2-
(L)]O3SCF3 was prepared. As for 5a, the triisopropylarsine
and triisopropylstibine derivatives 26 and 29 (Scheme 8) were
obtained from 2 and equivalent amounts of AsiPr3 and
SbiPr3. 26 and 29 are colorless solids, which are soluble in
polar solvents and for short periods of time can be handled in
air. Heating solutions of 26 and 29 in nitromethane at 60 °C
for several hours did not result in the formation of the η3:η3-
octadienediyl isomers; instead, the starting materials were
recovered unchanged. The arsine complex 26 proved also to
be inert toward an excess of AsiPr3 and did not afford a
rhodium η3-allyl derivative with a CH2AsiPr3 functionality.
It is worth noting that the reaction of 26 with SbiPr3 in a 1:1
ratio gave the stibine derivative 29 and AsiPr3, while on
treatment of 29 with an equivalent amount of AsiPr3 no
ligand exchange occurred. Since the bond distances increase
in the order Rh-P < Rh-As < Rh-Sb, it seems that not
only the different σ-donor properties of the EiPr3 ligands but
also steric requirements determine the stability of the five-
coordinated bis(butadiene) complexes [Rh(cis-η4-C4H6)2-
(EiPr3)]O3SCF3.
1
by the H NMR spectrum of the oily substance, in which
three sets of signals for the butadiene units appear. We as-
sume that initially the wanted product 33 (see Scheme 9) is
formed, which in vacuo loses the diene ligands in a stepwise
fashion and decomposes to species such as [Rh(η4-C4H6)-
(CO)(OTf)], [Rh(μ-OTf)(CO)2], etc.
To obtain the carbonyl complex 33 in analytically pure
form, dimeric [Rh(μ-Cl)(CO)2]2 (32) was first treated with
CF3SO3Ag and, after AgCl was filtered, subsequently with
butadiene. The colorless solid, dried for only a short period
of time at 0 °C in vacuo, is slightly air-sensitive and readily
soluble in acetone and dichloromethane. The IR spectrum of
33 displays a ν(CO) band at 2096 cm-1, which in comparison
with the uncharged analogues [M(η4-diene)2(CO)] (M = Fe,
Ru)33 is shifted by ca. 100-120 cm-1 to higher wavenum-
bers. In comparison with 26 and 29, the 1H NMR signals for
the butadiene protons of 33 are shifted by 0.4-1.4 ppm to
lower fields, which is consistent with the stronger π-acceptor
capability of CO in relation to AsiPr3 and SbiPr3. The
isocyanide complexes 34-39 were prepared by the same
route as their tertiary phosphine, arsine, and stibine counter-
parts and were completely characterized by analytical and
spectroscopic means. In the case of the isoprene derivatives,
the ratio of anti to syn stereoisomers was 78:22 for 35 and
76:24 for 38. On heating, neither 34 nor 37 undergoes a C-C
coupling reaction to furnish a product with a ligated η3:η3-
C8H12 unit.
The reactions of the bis(isoprene) and bis(2,3-dimethyl-
butadiene) compounds 3 and 4 (Scheme 1) with AsiPr3 and
SbiPr3, carried out under the same conditions used for the
preparation of 26, gave the substitution products 27 and 28
and 30 and 31, which owing to their 1H and 13C spectra are
structurally related to the triisopropylphosphine counter-
parts [Rh(cis-η4-C4H5Me)2(PiPr3)]O3SCF3 and [Rh(cis-η4-
C4H4Me2)2(PiPr3)]O3SCF3.11 Similar to the case for 26 and
29, the isoprene and 2,3-dimethylbutadiene analogues are
(32) In the anti isomers the methyl substituents of the two isoprene
ligands are on opposite sides and in the syn isomers they are on the same
side of the parallel C4 planes.
(33) (a) Koerner von Gustorf, E.; Buchkremer, J.; Pfajfer, Z.;
Grevels, F.-W. Angew. Chem. 1971, 83, 249-250; Angew. Chem., Int.
Ed. Engl. 1971, 10, 260-261. (b) Minniti, D.; Timms, P. L.
J. Organomet. Chem. 1983, 258, C12–C14. (c) Noda, I.; Yasuda, H.;
Nakamura, A. Organometallics 1983, 2, 1207–1214. (d) Cox, D. N.; Roulet,
R. Helv. Chim. Acta 1984, 67, 1365–1367.
(31) (a) Werner, H.; Wiedemann, R.; Steinert, P.; Wolf, J. Chem. Eur.
J. 1997, 3, 127–137. (b) Werner, H.; Schwab, P.; Bleuel, E.; Mahr, N.;
Steinert, P.; Wolf, J. Chem. Eur. J. 1997, 3, 1375–1384. (c) Kovacik, I.;
Laubender, M.; Werner, H. Organometallics 1997, 16, 5607–5609. (d) Gil-
Rubio, J.; Laubender, M.; Werner, H. Organometallics 1998, 17, 1202–1207.
(e) Werner, H.; Bachmann, P.; Laubender, M.; Gevert, O. Eur. J. Inorg.
Chem. 1998, 1217–1224.

5652 Organometallics, Vol. 29, No. 21, 2010
Bosch and Werner
Scheme 10
Scheme 11
occur. The 1H, 13C, and 31P NMR spectra of 43 reveal that
the five-coordinated cation consists of a ca. 7:1 mixture of
two isomers, which differ in the steric arrangement of the bis-
phosphinopropane and trimethylphosphine ligands. In the
major (called basal) isomer 43a, PMe3 and one of the PiPr2
units occupy two of the basal positions of the square pyr-
amid, while in the minor (called apical) isomer 43b both PiPr2
units are in the base. This structural proposal is most clearly
supported by the 31P NMR spectrum of the mixture of the
two isomers, which shows for 43a one doublet of doublets of
doublets for one and a doublet of doublets for the other PiPr2
moiety.38 For 43b, one doublet of doublets is observed for
both PiPr2 units.
The reaction of 40 with 2 equiv of PMe3 afforded, under
the same conditions as used for 43, the four-coordinated
complex 44 by displacement of the butadiene ligand. The
product is quite stable and can be stored under an inert
atmosphere for days at room temperature. The 31P NMR
spectrum of 44 is consistent with the presence of an AA0BB0X
spin system, which was confirmed by simulation using the
WIN-DAISY program of Bruker. The data were in excellent
agreement with those of [RuCl2{κ2-Ph2P(CH2)3PPh2}(PMe-
Ph2)2]39,40 and [Rh(η3-CH2C6H5){κ2-iPr2P(CH2)3PiPr2}].34
4. Rhodium-Catalyzed Cyclotetramerization of Butadiene.
Mechanistic studies on the nickel-catalyzed cyclotrimeriza-
tion of butadiene, carried out in particular by Wilke and his
group, unveiled that a nickel(II) complex of the composition
[Ni(η3:η2:η3-C12H18)] with a chain-like R,ω-bis(η3-allyl)ene
ligand is a key intermediate in this process.1b,5 This species is
presumably generated via the labile bis(butadiene) nickel(0)
[Ni(η4-C4H6)2], which could undergo an oxidative C-C
coupling of the butadiene ligands to give an isomeric [Ni-
(C8H12)] compound with the noncyclic C8H12 ligand either in
a η3:η3 or η1:η3 bonding mode. Subsequent addition of a
third molecule of butadiene leads to the isolated and struc-
turally characterized R,ω-bis(η3-allyl)ene complex [Ni(η3:η2:
η3-C12H18)], which in the presence of excess butadiene
affords 1,5,9-cyclododecatriene by ring closure. The postu-
lated intermediate [Ni(η4-C4H6)2] is then re-formed, and the
catalytic cycle can start again.
The reaction of 2 with 1 equiv of bidentate 1,3-C3H6-
(PiPr2)2 led to the formation of 40 by substitution of the
triflate and one butadiene ligand (Scheme 10). The red air-
stable product is not only inert in the solid state but also in
acetone or dichloromethane solution and does not rearrange
to a η3-allylphosphonium species, as observed for the labile
bis(triisopropylphosphine) analogue [Rh(η4-C4H6)(PiPr3)2]-
CF3SO3.11 A crystallographic study of 40 confirmed the
square-planar coordination sphere around the rhodium
atom with Rh-P distances of 2.297(3) A,29 which agree quite
˚
well with those in [Rh{anti-η3-(iPr3PCH2)CHCHCH2)(PiPr3)2]-
11
˚
PF6 (2.3264(8) and 2.3176(8) A). The bite angle P-Rh-P
of 94.76(12)° is similar to that in [Rh(η3-CH2C6H5){κ2-iPr2P-
(CH2)3PiPr2}] (96.99(4)°)34 and [Rh2H2(μ-H)2)(μ-O2ClO2){κ2-
iPr2P(CH2)3PiPr2}2] (94.9(1)°),35 respectively.
The butadiene complex 40 reacted in dichloromethane
with excess 1,3-C6H8 at room temperature to furnish the
cyclohexadiene counterpart 41 as an orange-red, slightly air-
sensitive solid. The properties as well as the 1H and 31P NMR
data of 41 are in accord with those of the structurally related
bis(triisopropylphosphine) derivative 15. When a solution of
41 in CD2Cl2 was heated at 50 °C, a gradual change of color
1
from red to light red occurred. After 3 h, the H and 31P
NMR signals of 41 had disappeared and a new set of signals
assigned to the rhodium(I) benzene complex 42 could be
observed. Typical data for 42 are the singlet at δ 7.35, cor-
responding to six protons, in the 1H NMR and the doublet at
δ 47.9 in the 31P NMR spectrum. The chemical shifts and the
1J(Rh,P) coupling constant of the phosphorus resonance
are in good agreement with the data for [(η6-C6H6)Rh-
36
(PEt3)2]BF4 and [{η6-C6H5(CH2)3PiPr2-κP}Rh{κ-iPr2P-
(CH2)3C6H5}]PF6,37 respectively.
If the nickel catalysts used for the formation of cyclo-1,5,9-
C12H18 were modified by adding a tertiary phosphine or
The reaction of 40 with 1 equiv of PMe3 in dichloro-
methane at -30 °C resulted in the formation of the 1:1 ad-
duct 43, which was isolated as a yellow solid in excellent yield
(Scheme 11). The anticipated attack of the phosphine at the
butadiene ligand (as takes place in the case of 18) did not
(38) The assignment is based on the difference in the 103Rh,31
P
coupling constants, which for the apical PiPr2 phosphorus atom is
152.0 Hz, in comparison with 1J(Rh,P) = 159.5 Hz for 3a. The
103Rh,31P coupling constant for the basal PiPr2 phosphorus atom is
109.0 Hz, similar to 1J(Rh,P) = 114.5 Hz for the PMe3 phosphorus
atom, which also occupies a basal position.
(39) (a) Baacke, M.; Hietkamp, S.; Morton, S.; Stelzer, O. Chem. Ber.
1982, 115, 1389–1398. (b) Baker, M. V.; Field, L. D. Inorg. Chem. 1987, 26,
2010–2011.
(40) (a) Steinborn, D.; Taube, R. Z. Chem. 1986, 26, 349–359.
(b) Taube, R. In Applied Homogeneous Catalysis with Organometallic
Compounds; Cornils, B., Herrmann, W. A., Eds.; VCH: Weinheim, Germany,
1996; Vol. 1, pp 507-520.
(34) Fryzuk, M. D.; McConville, D. H.; Rettig, S. J. J. Organomet.
Chem. 1993, 445, 245–256.
(35) Tani, K.; Yamagata, T.; Tatsuno, Y.; Saito, T.; Yamagata, Y.;
Yasuoka, N. J. Chem. Soc., Chem. Commun. 1986, 494–495.
(36) Bleeke, J. R.; Donaldson, A. J. Organometallics 1988, 7, 1588–
1596.
(37) Werner, H.; Canepa, G.; Ilg, K.; Wolf, J. Organometallics 2000,
19, 4756–4766.

Article
Organometallics, Vol. 29, No. 21, 2010 5653
phosphite, dimerization of butadiene occurred. In general, a
mixture of dimers is formed with 1,5-cyclooctadiene (COD)
and 4-vinylcyclohexene (VCH) as the main components.
With PCy3, the ratio of COD and VCH is ca. 1:1.1b Wilke
et al. assumed that in one of the initial stages of the reaction
the nickel(II) octadienediyl compound [Ni(η3:η3-C8H12)-
(PR3)] is generated, which undergoes two stepwise η3 to η1
haptotropic shifts to give, apart from transient [Ni(PR3)],
COD and VCH plus minor amounts of other butadiene
dimers.
Scheme 12
Taking these results into consideration, some common
aspects between the nickel-catalyzed dimerization and the
rhodium-catalyzed tetramerization of butadiene are percep-
tible. The first is that the reactions of [Rh{κ1-OS(O)2CF3}-
(η4-C4H6)2] (2), containing a labile triflate ligand, and (the
postulated) [Ni(η4-C4H6)2] with PCy3 occur via oxidative
C-C coupling of the butadiene ligands to yield compounds
with a η3:η3-cyclooctadienediyl ligand. Moreover, the nickel
complexes [Ni(η3:η3-C8H12)(PR3)] as well as the correspond-
ing rhodium derivatives [Rh(η3:η3-C8H12)(PR3)]X (such as
21) react under mild conditions with butadiene to yield a
mixture of C8 hydrocarbons with VCH as one of the main
components.
However, in the absence of free PR3 the bis(butadiene)
nickel compound [Ni(η4-C4H6)2] behaves differently from
the bis(butadiene)phosphine rhodium derivatives 5a and 6a.
While the first reacts with excess butadiene to yield cyclo-
1,5,9-C12H18 almost exclusively, the rhodium complexes 5a
and 6a give (in nitromethane at 75 °C) mixtures of (cyclo)-
oligomers and polymers. As already mentioned,10 the oligo-
meric fraction consists predominantly (ca. 90%) of a mixture
of C12 and C16 hydrocarbons. Among the tetramers, a high
selectivity for the cis,cis,trans,trans isomer of 1,5,9,13-cyclo-
hexadecatetraene was observed. Raising the temperature to
95 °C resulted in a higher percentage of the tetramers in the
oligomeric fraction but also in a significant increase of the
amount of polymers.
To elucidate the influence of the solvent, the type of
phosphine ligand, and the ratio Rh:PR3, a series of experi-
ments was carried out.41 The dimeric rhodium(I) derivative
1 was used as the catalyst precursor. Under standard condi-
tions (10 mL of solvent, 3 mL of butadiene, T = 90 °C, t = 5 h,
Rh:C4H6 = 1:300), the highest amounts of (cyclo)oligomers of
butadiene were formed if 2 mol of PR3 (R = iPr, Cy) was
used per mole of 1. In the absence of phosphine, only traces
of (cyclo)oligomers were formed. The same result is obtained
with the ratio of 1:PR3 = 1:4, probably because in this case a
deactivation of the catalyst occurs. Regarding the influence
of the solvent, the catalytic activity increases significantly in
the order CH3CN = THF < acetone < methanol = nitro-
methane. Similarly, the selectivity for 1,5,9,13-C16H24 com-
pared with C8, C12, and other C16 (cyclo)oligomers42 in-
creases along CH3CN < THF < acetone = methanol <
nitromethane. In methanol and nitromethane, the system 1/
PCy3 is slightly more active than the counterpart 1/PiPr3. A
surprising result is that NiPr3, which in contrast to PiPr3 does
not react with 2 to yield [Rh(s-cis-η4-C4H6)2(NiPr3)]O3SCF3,
proved to be a good cocatalyst and favors the formation of
1,5,9,13-C16H24. In the first 10 min of the reaction (under
standard conditions with the ratio 1:NiPr3 = 1:2) only
1,5,9,13-C16H24 is generated and no other C8, C12, or C16
(cyclo)oligomers can be detected by GC/MS. The system 1/
NiPr3, however, is not stable for a longer period of time, and
after ca. 1 h a distinct decrease in the catalytic activity (and
the selectivity for 1,5,9,13-C16H24 as well) is observed. In
contrast to the case for 5a, which for the catalytic studies was
prepared in situ from 2 and an equimolar amount of PiPr3,
the arsine and stibine analogues 26 and 29 were catalytically
inactive in the presence of butadiene.
To summarize these results, it is not clear as yet what the
final steps of the catalytic cycle for the tetramerization of
butadiene to cis,cis,trans,trans-1,5,9,13-cyclohexatetraene
45 are. With Wilke’s results as a given, we assume that the
ionic intermediate A (which, as mentioned above, is in equi-
librium with the isolated compound 19 in polar solvents such
as nitromethane) reacts in the presence of excess butadiene
by replacing the phosphine ligand to yield the butadiene
adduct B (Scheme 12). This undergoes a 2-fold C-C cou-
pling reaction to generate C and subsequently D. In the final
step, and in the presence of butadiene and PiPr3, the 16-
membered cyclotetraene 45 is formed and the precursor 5a is
regenerated. We assume that the byproducts of the catalytic
reaction (all-trans-1,3,6,10-dodecatetraene, cis,trans,trans-
1,3,6,10-dodecatetraene, trans-1,4-polybutadiene, etc.)42
probably originate from the labile chain-like R,ω-bis(η3-
allyl)diene species D. Similarly, Wilke et al. proposed that
the linear dodecatrienes, observed as byproducts in the
nickel-catalyzed trimerization of butadiene to cyclo-1,5,9-
C12H18, are generated from the open-chain [Ni(η3:η2:η3-
C12H18)] intermediate.1b,5
The unanswered question remains why [Ni(η3:η2:η3-
C12H18)] undergoes a reductive C-C coupling to furnish
cyclo-1,5,9-C12H18 and the related intermediate C preferen-
tially reacts with another molecule of butadiene to give D and
finally 45. One reason could be that [Ni(η3:η2:η3-C12H18)] is a
18-electron and C a 16-electron species. The latter not only is
electronically unsaturated but also has an open coordination
site to which a butadiene molecule can be bound. We assume
that this process is favored in comparison with the addition
of PiPr3, possibly for steric reasons. Although the configu-
ration of D is unknown, a simple model suggests that the co-
ordination of the R,ω-bis(η3-allyl)diene ligand to rhodium(III)
(41) For further details of the catalytic studies see: Bosch, M.
€
€
Dissertation, Universitat Wurzburg, 2001, Chapter 7 and pp 346-356.
(42) GC/MS analyses confirmed that the C12 fraction consists mainly
of a 2:1 mixture of all-trans-1,3,6,10-dodecatetraene and cis,trans,trans-
1,3,6,10-dodecatetraene, in addition to small amounts of all-trans-1,5,9-
cyclododecatriene and cis,trans,trans-1,5,9-cyclododecatriene. The lin-
ear tetraenes, cyclic trienes, and trans-1,4-polybutadiene were identified
by 1H and 13C NMR spectroscopy.

5654 Organometallics, Vol. 29, No. 21, 2010
Bosch and Werner
in D causes a significant ring strain and thus facilitates the
reductive elimination of 45. A theoretical study in prospect
should provide more insight into the energetic aspects and
mechanism of the process.27
Experimental Section
All reactions were carried out under an atmosphere of argon
by Schlenk techniques. NaB(Arf)449 and the rhodium complexes
1,8a 2-4, 5a,11 12, 14,8a and 3250 were prepared as described
in the literature. PiPr3, PCy3, PtBu2Me, and PtBu2Ph were
commercial products from Strem Chemicals. AsiPr3 and SbiPr3
were gifts from members of our research group. The commer-
cially available olefins were used without further purification.
NMR spectra were recorded on Bruker AC 200, Bruker Avance
300, and Bruker AMX 400 instruments at room temperature, if
not stated otherwise. IR spectra were recorded on Perkin-Elmer
1420 and Bruker IFS FT-IR spectrometers. Mass spectra were
recorded on 8200 Finnigan MAT and Varian CH7MAT instru-
ments. Melting points were measured by DTA. Abbreviations
used: s, singlet; d, doublet; t, triplet; q, quartet; sept, septet; m,
multiplet; br, broadened signal. The term vt indicates a virtual
Conclusions
The present investigation has shown that the well-known
rhodium(I) cyclooctene dimer 1 is a suitable starting material
for the preparation of a series of rhodium(I) mono- and bis-
(diolefin) complexes. The most noteworthy representatives
of this series are the bis(butadiene) compounds [Rh(s-cis-η4-
C4H6)2(PR3)]X (5a,b and 6a,b), which catalyze the (cyclo)-
oligomerization of butadiene. The first and rate-determining
step of this reaction consists of the C-C coupling of the
butadiene ligands of 5a,b or 6a,b to afford the rhodium(III)
octadienediyl isomers 19-22, which with excess C4H6 under-
go further C-C coupling reactions leading to C12, C16, and
traces of higher oligomers and to trans-1,4-polybutadiene.
Among these C-C coupling products, the tetramer 45 de-
serves particular attention because, in contrast to the transi-
tion-metal-catalyzed cyclotrimerization, almost nothing is
known about the analogous cyclotetramerization of C4H6.
In 1954, Reed reported that in the nickel-catalyzed oligo-
merization of butadiene with nickel carbonyl phosphine and
phosphite compounds as catalysts, apart from 1,5-cyclooc-
tadiene as the main product (yield 30-40%), a small amount
of a configurationally uncharacterized cyclic tetramer was
obtained.43 Somewhat later, Dzhemilev et al.44 and Miyake
et al.45 generated two catalytic systems from TiCl4/Et2AlCl/
2-vinylfuran and from nickel η3-allyl compounds, both of
which convert butadiene to a mixture of linear and cyclic
oligo- and polyenes. With the titanium system, which was
previously used by Wilke for the polymerization and cyclo-
trimerization of butadiene,46 a mixture of mainly all-trans
cyclotrimers and all-trans cyclotetramers in a ratio of 7:3 was
formed. With the nickel η3-allyl compounds, a variety of C8,
C12, C16, C20, and C24 (cyclo)oligomers were obtained. Among
the cyclotetramers, 45 has not been identified.45 In contrast
to these results, the rhodium(I) bis(butadiene) and rhodium-
(III) cyclooctadienediyl complexes 5a,b, 6a,b, and 19-22
provide a rather narrow product distribution of butadiene
oligomers and polymers and a relatively high selectivity for
45 in the oligomeric fraction.
5
3
triplet, and N = 3J(P,H) þ J(P,H), 1J(P,C) þ J(P,C), or 2J(P,
4
C) þ J(P,C). The coupling constants are given in hertz. The
molar conductivity ΛM was determined in nitromethane using a
Schott CG 851 conductometer equipped with an LF 1050 cell.
Kinetic measurements were carried out in NMR tubes using a
Bruker Avance 300 spectrometer equipped with a variable-
temperature unit. The solvent was CD3NO2. The signals of
B(Arf)4- were used as internal standards for the determination
of the concentration of 19 and 20, respectively. A general
procedure for the catalytic reactions leading to (cyclo)oligo-
mers and polymers of butadiene and for the separation and the
analytical and spectroscopic data for 45 was already given.10
Preparation of [Rh(s-cis-η4-C4H6)2(PiPr3)]B(Arf)4 (5b). A so-
lution of 5a (320 mg, 0.61 mmol) in dichloromethane (20 mL)
was treated at 0 °C with NaB(Arf)4 (541 mg, 0.61 mmol). After it
was warmed to room temperature, the solution was stirred for
30 min. An off-white solid precipitated. The solution was filte-
red, and the filtrate was concentrated to ca. 2 mL in vacuo. After
the argon atmosphere was replaced by butadiene and pentane
(30 mL) was added, a colorless solid was formed. It was
decanted from the solution, washed three times with pentane
(5 mL each), and dried in vacuo: yield 591 mg (83%). Anal.
Calcd for C49H45BF24PRh: C, 47.67; H, 3.67. Found: C, 47.32;
H, 3.54. 1H NMR (200 MHz, CD2Cl2): δ 7.76 (m, 8 H, o-H of
Arf), 7.60 (br s, 4 H, p-H of Arf), 5.55 (m, 4 H, CH2d
3
CHCHdCH2), 3.21 (br d, J(H,H) = 6.9 Hz, 4 H, H of CH2
cis to dCH), 2.54 (m, 3 H, PCHCH3), 1.37 (dd, 3J(P,H) = 13.7,
3J(H,H) = 7.1 Hz, 18 H, PCHCH3), 1.30 (br d, 3J(H,H) = 10.2
Hz, 4 H, H of CH2 trans to dCH). 13C NMR (50.3 MHz,
CD2Cl2): δ 162.2 (q, 1J(B,C) = 49.9 Hz, ipso-C of Arf), 135.2 (br
s, o-C of Arf), 129.3 (qq, 2J(F,C) = 31.6, 4J(F,C) = 2.8 Hz, m-C
of Arf), 125.0 (q, 1J(F,C) = 272.3 Hz, CF3), 117.9 (sept, 3J(F,C) =
3.9 Hz, p-C of Arf), 89.9 (d, 1J(Rh,C)
= 3.3 Hz,
CH2dCHCHdCH2), 52.4 (dd, 2J(Rh,C) = 8.5, 1J(P,C) = 3.4
To increase the amount of 45 and of other C16 isomers,
which could be suitable for the preparation of muscone,47
further variations of the ligand L in the rhodium(I) precursor
[Rh(s-cis-η4-C4H6)2(L)]X might be successful. Our work, as
well as that of Wilke and his group,1,5,24 indicates that for
both the rhodium- and the nickel-catalyzed (cyclo)oligo-
merization of butadiene sterically demanding phosphines
or related phosphites seem to be promising tools. Recent
theoretical investigations support this assumption.48
Hz, CH2dCHCHdCH2), 28.1 (d, 1J(P,C)
= 19.4 Hz,
PCHCH3), 20.3 (s, PCHCH3). 19F NMR (188.2 MHz, CD2Cl2):
δ -63.1 (s). 31P NMR (81.0 MHz, CD2Cl2): δ 47.8 (d, 1J(Rh,P) =
157.8 Hz).
Preparation of [Rh(s-cis-η4-C4H6)2(PCy3)]CF3SO3 (6a). A
solution of 2 (542 mg, 1.40 mmol) in dichloromethane (50 mL)
was treated with PCy3 (391 mg, 1.40 mmol) and stirred for 30
min at room temperature. After the solution was concentrated
to ca. 2 mL in vacuo, the argon atmosphere was replaced by
butadiene and pentane (30 mL) was added. A colorless solid was
formed. It was decanted from the solution, washed three times
with pentane (5 mL each), and dried in vacuo: yield 842 mg
(94%); mp 77 °C dec. ΛM = 72 cm2 Ω-1 mol-1. Anal. Calcd for
C27H45F3O3PRhS: C, 50.62; H, 7.08; S, 5.01. Found: C, 50.86;
H, 6.80; S, 4.68. IR (CH2Cl2): ν(OSOasym) 1265, ν(CFasym) 1161,
(43) Reed, H. W. B. J. Chem. Soc. 1954, 1931–1941.
(44) (a) Dzhemilev, U. M.; Gubaidullin, L. Y. Zh. Org. Khim. 1976,
12, 44-46; Chem. Abstr. 1976, 84, 121244. (b) Tolstikov, G. A.;
Dzhemilev, U. M.; Gubaidullin, L. Y. Izv. Akad. Nauk SSSR, Ser.
Khim. 1975, 2, 487; Chem. Abstr. 1975, 82, 139467.
(45) Miyake, A.; Kondo, H.; Nishino, M. Angew. Chem. 1971, 83,
851-852; Angew. Chem., Int. Ed. Engl. 1971, 10, 802-803.
(46) Wilke, G. Angew. Chem. 1957, 69, 397–398.
(49) Brookhart, M.; Grant, B.; Volpe, A. F., Jr. Organometallics
1992, 11, 3920–3922.
(47) Baker, R. Chem. Rev. 1973, 73, 487–530.
(48) Tobisch, S. Adv. Organomet. Chem. 2003, 49, 167–224.
(50) McCleverty, J. A.; Wilkinson, G. Inorg. Synth. 1966, 8, 211–214.

Article
Organometallics, Vol. 29, No. 21, 2010 5655
ν(OSOsym) 1031 cm-1. 1H NMR (400 MHz, CD2Cl2): δ 5.91 (m,
4 H, CH2dCHCHdCH2), 3.21 (m, 4 H, H of CH2 cis to dCH),
43.19; H, 5.53; S, 6.07. Found: C, 42.95; H, 5.46; S, 6.02. MS
(EI): m/z 528 (Mþ), 474 (Mþ - C4H6), 324 (Mþ - C4H6 -
CF3SO3), 306 (Mþ - PtBu2Ph). IR (CH2Cl2): ν(OSOasym) 1273,
ν(CFsym) 1254, ν(CFasym) 1173, ν(OSOsym) 1031 cm-1. 1H NMR
(400 MHz, CD2Cl2): δ 7.69 (m, 2 H, o-H of C6H5), 7.46 (m, 3 H,
m-H and p-H of C6H5), 5.31 (m, 4 H, CH2dCHCHdCH2), 3.22
(br d, 3J(H,H) = 5.0 Hz, 2 H, H of CH2 cis to dCH), 1.58 (br d,
3J(H,H) = 12.0 Hz, 2 H, H of CH2 trans to dCH), 1.41 (d, 3J(P,
H) = 13.8 Hz, 18 H, PCCH3). 13C NMR (100.6 MHz, CD2Cl2):
δ 134.6 (d, 2J(P,C) = 10.2 Hz, o-C of C6H5), 131.0 (dd, 1J(P,C) =
31.5, 2J(Rh,C) = 2.0 Hz, ipso-C of C6H5), 130.6 (d, 4J(P,C) = 2.0
2.2-1.1 (br m, 37 H, C6H11 and H of CH2 trans to dCH). 13
C
1
NMR (100.6 MHz, CD2Cl2): δ 120.9 (q, J(F,C) = 322.5 Hz,
CF3), 90.8 (br s, CH2dCHCHdCH2), 52.7 (br s, CH2d
CHCHdCH2), 38.2 (br s, CH of C6H11), 31.0 (br s, γ-CH2 of
C6H11), 28.1 (d, 2J(P,C) = 9.2 Hz, R-CH2 of C6H11), 26.8 (s, β-
CH2 of C6H11). 19F NMR (376.4 MHz, CD2Cl2): δ -78.5 (s). 31
P
NMR (162.0 MHz, CD2Cl2): δ 34.2 (d, 1J(Rh,P) = 159.4 Hz).
Preparation of [Rh(s-cis-η4-C4H6)2(PCy3)]B(Arf)4 (6b). This
compound was prepared as described for 5b from 6a (286 mg,
0.45 mmol) and NaB(Arf)4 (399 mg, 0.45 mmol). A colorless
solid was obtained: yield 500 mg (86%); mp 73 °C dec. Anal.
Calcd for C58H57BF24PRh: C, 51.42; H, 4.24. Found: C, 50.93;
H, 4.24. 1H NMR (200 MHz, CD2Cl2): δ 7.75 (m, 8 H, o-H of
Arf), 7.59 (br s, 4 H, p-H of Arf), 5.55 (m, 4 H, CH2d
3
Hz, p-C of C6H5), 128.2 (d, J(P,C) = 9.2 Hz, m-C of C6H5),
89.4 (br s, CH2dCHCHdCH2), 51.8 (br s, CH2dCHCHd
CH2), 36.9 (d, 1J(P,C) = 13.2 Hz, PCCH3), 30.5 (d, 2J(P,C) =
5.1 Hz, PCCH3), signal of CF3 not exactly located. 19F NMR
(376.4 MHz, CD2Cl2): δ -78.1 (s). 31P NMR (81.0 MHz,
CD2Cl2): δ 59.8 (d, 1J(Rh,P) = 180.2 Hz).
3
CHCHdCH2), 3.14 (d, J(H,H) = 6.2 Hz, 4 H, H of CH2 cis
Preparation of [(η6-C6H6)Rh(η4-C6H8)]CF3SO3 (10). A solu-
tion of 1 (270 mg, 0.29 mmol) in diethyl ether/pentane (1:2,
20 mL) was treated with 1,3-cyclohexadiene (500 μL, 5.2 mmol)
and irradiated for 1 h in an ultrasound bath. After the reaction
mixture was stored for 30 min, a red-brown solid precipitated.
The solution was decanted, and the remaining solid residue was
washed three times with pentane (5 mL each) and dried in vacuo:
to dCH), 2.4-1.1 (br m, 37 H, C6H11 and H of CH2 trans to d
CH). 13C NMR (50.3 MHz, CD2Cl2): δ 162.2 (q, 1J(B,C) = 49.6
Hz, ipso-C of Arf), 135.2 (br s, o-C of Arf), 129.3 (qq, 2J(F,C) =
31.3, 4J(F,C) = 2.6 Hz, m-C of Arf), 125.0 (q, 1J(F,C) = 272.5
3
Hz, CF3), 117.9 (sept, J(F,C) = 3.3 Hz, p-C of Arf), 89.9 (d,
1J(Rh,C) = 4.2 Hz, CH2dCHCHdCH2), 52.8 (dd, 2J(Rh,C) =
8.3, 1J(P,C) = 3.7 Hz, CH2dCHCHdCH2), 38.4 (d, 1J(P,C) =
18.5 Hz, CH of C6H11), 31.1 (br s, γ-CH2 of C6H11), 28.1 (d,
2J(P,C) = 9.0 Hz, R-CH2 of C6H11), 26.8 (s, β-CH2 of C6H11).
19F NMR (188.2 MHz, CD2Cl2): δ -63.1 (s). 31P NMR (81.0
MHz, CD2Cl2): δ 34.4 (d, 1J(Rh,P) = 157.6 Hz).
yield 184 mg (78%); mp 102 °C dec. ΛM = 62 cm2 Ω-1 mol-1
Anal. Calcd for C13H14F3O3RhS: C, 38.06; H, 3.44; S, 7.82.
Found: C, 37.77; H, 3.42; S, 7.88. IR (CH2Cl2): ν(OSOasym
.
)
1278, ν(CFsym) 1250, ν(CFasym) 1170, ν(OSOsym) 1031 cm-1. 1H
NMR (200 MHz, CD2Cl2): δ 6.90 (s, 6 H, C6H6), 5.65 (m, 2 H,
CHdCHCH2), 4.64 (m, 2 H, CHdCHCH2), 1.70 (brd, 3J(H,H) =
12.7 Hz, 2 H of dCHCH2), 1.28 (br d, 3J(H,H) = 11.7 Hz, 2 H
of dCHCH2).13CNMR(50.3MHz,CD2Cl2):δ121.4 (q, 1J(F,C) =
321.4 Hz, CF3), 102.6 (d, 1J(Rh,C) = 3.3 Hz, C6H6), 86.0 (d,
1J(Rh,C) = 7.5 Hz, CHdCHCH2), 71.9 (d, 1J(Rh,C) = 14.0
Hz, CHdCHCH2), 25.3 (s, CH2). 19F NMR (188.2 MHz,
CD2Cl2): δ -79.0 (s).
Preparation of [Rh(s-cis-η4-C4H6)2(PtBu2Me)]CF3SO3 (7).
This compound was prepared as described for 6a from 2 (108
mg, 0.28 mmol) and PtBu2Me (56 μL, 0.28 mmol). A colorless
solid was obtained: yield 146 mg (98%); mp 64 °C dec. ΛM = 71
cm2 Ω-1 mol-1. Anal. Calcd for C18H33F3O3PRhS: C, 41.55; H,
6.39; S, 6.16. Found: C, 41.19; H, 6.35; S, 6.10. IR (CH2Cl2):
ν(OSOasym) 1279, ν(CFsym) 1250, ν(CFasym) 1161, ν(OSOsym
)
1031 cm-1 1H NMR (200 MHz, CD2Cl2): δ 5.91 (m, 4 H,
.
CH2dCHCHdCH2), 3.16 (m, 4 H, H of CH2 cis to dCH), 1.53
(d, 2J(P,H) = 6.7 Hz, 3 H, PCH3), 1.12 (d, 3J(P,H) = 13.6 Hz, 18
H, PCCH3), signal of H of CH2 trans to dCH not exactly loc-
ated. 13C NMR (50.3 MHz, CD2Cl2): δ 90.9 (br s, CH2d
Preparation of [{η5-C5H4CH(CH3)2}Rh{η5-C5H4C(dCH2)-
CH3}]CF3SO3 (11). This compound was prepared as described
for 10 from 1 (217 mg, 0.23 mmol) and 6,60-dimethylfulvene (500
μL, 4.1 mmol). A colorless solid was obtained: yield 183 mg
(86%); mp 78 °C dec. ΛM = 105 cm2 Ω-1 mol-1. Anal. Calcd for
C17H20F3O3RhS: C, 43.98; H, 4.34; S, 6.91. Found: C, 43.52; H,
4.17; S, 6.87. IR (CH2Cl2): ν(OSOasym) 1270, ν(CFsym) 1250,
1
CHCHdCH2), 54.5 (br s, CH2dCHCHdCH2), 38.0 (d, J(P,
C) = 12.8 Hz, PCCH3), 30.4 (d, 2J(P,C) = 4.1 Hz, PCCH3), 6.8
(d, 1J(P,C) = 20.6 Hz, PCH3), signal of CF3 not exactly located.
19F NMR (188.2 MHz, CD2Cl2): δ -79.0 (s). 31P NMR (81.0
MHz, CD2Cl2): δ 45.2 (d, 1J(Rh,P) = 159.4 Hz).
1
ν(CFasym) 1160, ν(OSOsym) 1031 cm-1. H NMR (200 MHz,
CD2Cl2): δ 6.05, 5.89, 5.77 (all br s, 8 H, CH of five-membered
rings), 5.58, 5.30 (both br s, 2 H, CdCH2), 2.59 (sept, 3J(H,H) =
6.9 Hz, 1 H, CHCH3), 2.00 (s, 3 H, CH3), 1.16 (d, 3J(H,H) = 6.9
Hz, 6 H, CHCH3). 13C NMR (50.3 MHz, CD2Cl2): δ 133.5 (s, d
Preparation of [Rh(s-cis-η4-C4H6)2(PPh3)]CF3SO3 (8). This
compound was prepared as described for 6a from 2 (178 mg,
0.46 mmol) and PPh3 (121 mg, 0.46 mmol). A colorless solid was
obtained: yield 267 mg (93%). 1H NMR (300 MHz, CD2Cl2): δ
7.63 (m, 6 H, o-H of C6H5), 7.53 (m, 9 H, m-H and p-H of C6H5),
1
CCH3), 121.4 (q, J(F,C) = 321.4 Hz, CF3), 119.2 (s, CH2),
1
119.9, 109.6 (both d, J(Rh,C) = 7.1 Hz, C-R of five-mem-
3
6.03 (m, 4 H, CH2dCHCHdCH2), 3.38 (d, 4 H, J(H,H) =
bered rings), 87.1, 86.7, 85.6, 83.7 (all d, 1J(Rh,C) = 7.1 Hz, CH
of five-membered rings), 26.6 (s, CHCH3), 23.2 (s, CHCH3),
21.1 (s, dCCH3). 19F NMR (188.2 MHz, CD2Cl2): δ -78.6 (s).
Preparation of [Rh{K1-OS(O)2CF3}(η4-C6H8)(PiPr3)] (13). A
solution of 12 was generated in situ from 1 (145 mg, 0.15 mmol)
and PiPr3 (60 μL, 0.31 mmol) in pentane (10 mL) and then trea-
ted with 1,3-cyclohexadiene (1.0 mL, 10.5 mmol). The solution
was stirred for 15 min at room temperature and, after it was
concentrated to ca. 2 mL in vacuo, an orange solid precipitated.
The mixture was cooled to -30 °C, and then the solution was de-
canted from the precipitate. The solid was washed three times
with pentane (-30 °C, 2 mL each) and dried in vacuo: yield 147
mg (97%); mp 87 °C dec. Anal. Calcd for C16H29F3O3PRhS: C,
39.03; H, 5.94; S, 6.51. Found: C, 38.72; H, 5.57; S, 6.19. IR
(CH2Cl2): ν(OSOasym) 1317, ν(CFsym) 1252, ν(CFasym) 1178,
ν(OSOsym) 1031 cm-1. 1H NMR (400 MHz, CD2Cl2): δ 5.11 (br
s, 2 H, CHdCHCH2), 4.38 (br s, 2 H, CHdCHCH2), 2.18 (m, 3
H, PCHCH3), 1.88 (br d, 3J(H,H) = 11.7 Hz, 2 H of CH2CH2),
1.26 (dd, 3J(P,H) = 13.9, 3J(H,H) = 7.2 Hz, 18 H, PCHCH3),
6.3 Hz, H of CH2 cis to dCH), 0.73 (dd, 3J(P,H) = 11.1, 3J(H,H) =
10.2 Hz, H of CH2 trans to dCH). 13C NMR (75.5 MHz,
2
CD2Cl2): δ 134.1 (d, J(P,C) = 10.4 Hz, o-C of C6H5), 132.7
(d, 1J(P,C) = 44.4 Hz, ipso-C of C6H5), 131.3 (d, 4J(P,C) = 2.3
Hz, p-C of C6H5), 129.2 (d, 3J(P,C) = 10.2 Hz, m-C of C6H5),
93.0 (d, 1J(Rh,C) = 2.5 Hz, CH2dCHCHdCH2), 58.4 (dd,
1J(Rh,C) = 8.6, 2J(P,C) = 2.1 Hz, CH2dCHCHdCH2), signal
of CF3 not exactly located. 19F NMR (282.3 MHz, CD2Cl2):
δ -78.8 (s). 31P NMR (121.5 MHz, CD2Cl2):δ 45.6 (d, 1J(Rh,P) =
164.8 Hz).
Preparation of [Rh{K1-OS(O)2CF3}(η4-C4H6)(PtBu2Ph)] (9).
A solution of 2 (70 mg, 0.18 mmol) in dichloromethane (5 mL)
was treated with PtBu2Ph (46 μL, 0.18 mmol) and stirred for 30
min at room temperature. After the solution was concentrated
to ca. 2 mL in vacuo, pentane (10 mL) was added. A red solid
was formed. The mixture was cooled to -30 °C, and then the
solution was decanted from the solid. The solid was washed
three times with pentane (3 mL each) and dried in vacuo: yield 88
mg (94%); mp 69 °C dec. Anal. Calcd for C19H29F3O3PRhS: C,
3
0.94 (br d, J(H,H) = 11.7 Hz, 2 H of CH2CH2). 13C NMR

5656 Organometallics, Vol. 29, No. 21, 2010
Bosch and Werner
1
(100.6 MHz, CD2Cl2): δ 119.9 (q, J(F,C) = 319.0 Hz, CF3),
9.17; S, 2.87. 1H NMR (400 MHz, CD2Cl2): δ 4.63 (br m, 1 H, H
of allylic CH2 in cis position to central allylic CH), 3.11 (m, 1 H,
PCH2CH), 2.67 (br m, 1 H, H of central allylic CH), 2.33 (m, 6
H, CH of RhPC6H11), 2.27 (m, 1 H, one H of PCH2), 2.05-1.20
(br m, 95 H, CH2 of C6H11, CH of CPC6H11, PCH2, and H of
CH2 in trans position to central allylic CH). 13C NMR (100.6
MHz, CD2Cl2): δ 121.4 (q, 1J(F,C) = 321.9 Hz, CF3), 92.8 (d,
1J(Rh,C) = 5.5 Hz, central allylic CH), 45.1 (br m, PCH2CH),
42.5 (br m, allylic CH2), 39.7, 38.5 (both d, 1J(P,C) = 26.2 Hz,
CH of RhPC6H11), 31.7 (s, γ-CH2 of CPC6H11), 31.4 (d, 1J(P,C) =
37.4 Hz, CH of CPC6H11), 30.9, 30.4 (both s, γ-CH2 of
RhPC6H11), 28.5, 28.4, 28.3, 28.2 (all s, β-CH2 of C6H11),
83.1 (br s, CHdCHCH2), 71.7 (br s, CHdCHCH2), 24.4 (d,
1J(P,C) = 20.4 Hz, PCHCH3), 21.3 (s, CH2), 19.8 (s, PCHCH3).
19F NMR (376.4 MHz, CD2Cl2): δ -78.1 (s). 31P NMR (162.0
MHz, CD2Cl2): δ 50.6 (d, 1J(Rh,P) = 181.4 Hz).
Preparation of [Rh(η4-C6H8)(PiPr3)2]CF3SO3 (15). (a) Asolu-
tion of 14 was generated in situ from 1 (126 mg, 0.13 mmol) and
PiPr3 (104 μL, 0.52 mmol) in dichloromethane (10 mL) at 0 °C and
then treated with 1,3-cyclohexadiene (0.5 mL, 5.2 mmol). A change
of color from violet to red occurred. After it was warmed to room
temperature, the solution was concentrated to ca. 2 mL in vacuo.
Addition of pentane (30 mL) led to the precipitation of a red solid,
which was filtered, washed three times with pentane (0 °C, 5 mL
each), and dried in vacuo: yield 139 mg (82%).
2
27.5, 27.4 (both d, J(P,C) = 13.5 Hz, R-CH2 of RhPC6H11),
27.2 (d, 3J(P,C) = 19.5 Hz, β-CH2 of CPC6H11), 27.0, 26.9 (both
d, 2J(P,C) = 11.0 Hz, R-CH2 of RhPC6H11), 25.8 (s, R-CH2 of
CPC6H11), 16.7 (d, 1J(P,C) = 17.6 Hz, PCH2). 19F NMR (376.4
MHz, CD2Cl2): δ -78.8 (s). 31P NMR (162.0 MHz, CD2Cl2): δ
41.5 (ddd, 1J(Rh,P) = 181.7, 2J(P,P) = 20.8, 4J(P,P) = 11.5 Hz,
(b) A solution of 11 (137 mg, 0.28 mmol) in dichloromethane
(10 mL) was treated at 0 °C with PiPr3 (55 μL, 0.28 mmol) and
stirred for 15 min at 0 °C. After it was warmed to room tem-
perature, the reaction mixture was worked up as described for
1
2
(a): yield 155 mg (85%); mp 53 °C dec. ΛM = 84 cm2 Ω-1 mol-1
.
RhP), 37.0 (dd, J(Rh,P) = 186.1, J(P,P) = 20.8 Hz, RhP),
20.9 (d, 4J(P,P) = 11.5 Hz, CP).
Anal. Calcd for C25H50F3O3P2RhS: C, 46.01; H, 7.72; S, 4.91.
Found: C, 45.49; H, 7.60; S, 4.98. IR (CH2Cl2): ν(OSOasym
1270, ν(CFasym) 1159, ν(OSOsym) 1032 cm-1 1H NMR (400
Preparation of [Rh(η3:η3-C8H12){K1-OS(O)2CF3}(PiPr3)]
(19). A solution of 5a (175 mg, 0.34 mmol) in dichloromethane
(10 mL) was heated under reflux for 6 h. A change of color from
orange to deep red occurred. After the reaction mixture was
cooled to room temperature, the solvent was removed in vacuo.
The oily residue was washed three times with pentane (5 mL
each) and the resulting red solid recrystallized from dichloro-
methane/pentane (1:5): yield 131 mg (75%); mp 104 °C dec.
)
.
MHz, CD2Cl2): δ 5.29 (br s, 2 H, CHdCHCH2), 4.98 (br s, 2 H,
CHdCHCH2), 2.42 (m, 6 H, PCHCH3), 1.76 (br d, 3J(H,H) =
12.4 Hz, 2 H of CH2CH2), 1.37 (dvt, N = 10.1, 3J(H,H) = 6.7
3
Hz, 36 H, PCHCH3), 1.10 (br d, J(H,H) = 12.4 Hz, 2 H of
CH2CH2). 19F NMR (188.2 MHz, CD2Cl2): δ -78.6 (s). 31P
NMR (81.0 MHz, CD2Cl2): δ 41.2 (d, 1J(Rh,P) = 170.3 Hz).
Preparation of [Rh{η4-C5H4C(CH3)2}(PiPr3)2]CF3SO3 (16).
A solution of 14 was generated in situ from 1 (215 mg, 0.23
mmol) and PiPr3 (180 μL, 0.92 mmol) in dichloromethane (20
mL) at room temperature. Addition of 6,60-dimethylfulvene (0.5
mL, 4.1 mmol) led to a change of color from violet to deep green.
The solution was stirred for 15 min and then concentrated to ca.
2 mL in vacuo. After pentane (30 mL) was added, a deep green
solid precipitated. It was separated from the solution, washed
three times with pentane (0 °C, 5 mL each), and dried in vacuo:
Λ
M = 73 cm2 Ω-1 mol-1. Anal. Calcd for C18H33F3O3PRhS: C,
41.55; H, 6.39; S, 6.16. Found: C, 41.37; H, 6.16; S, 6.01. IR
(CH2Cl2): ν(OSOasym) 1260 br, ν(CFsym) 1239, ν(CFasym) 1162,
1
ν(OSOsym) 1031 cm-1. H NMR (400 MHz, CD2Cl2): δ 5.23
(ddd, 3J(H,H) = 11.6, 3J(H,H) = 10.6, 3J(H,H) = 7.0 Hz, 2 H,
CHCHCH2 of allylic system), 4.88 (dd, 3J(H,H) = 7.0,
4J(H,H) = 1.8 Hz, 2 H, cis-disposed H of allylic CH2), 4.21
(ddd, 3J(H,H) = 10.6, 3J(H,H) = 3.5, 4J(H,H) = 1.8 Hz, 2 H,
CHCHCH2 of allylic system), 3.07 (dd, 3J(H,H) = 11.6, 3J(P,H) =
6.3 Hz, 2 H, trans-disposed H of allylic CH2), 2.63 (m, 3 H,
PCHCH3), 2.28, 1.53 (both m, 2 H each, CH2 next to the allylic
system), 1.28 (dd, 3J(P,H) = 14.3, 3J(H,H) = 7.0 Hz, 9 H,
yield 278 mg (89%); mp 118 °C dec. ΛM = 102 cm2 Ω-1 mol-1
Anal. Calcd for C27H52F3O3P2RhS: C, 47.79; H, 7.72; S, 4.73.
Found: C, 47.29; H, 7.26; S, 4.65. IR (CH2Cl2): ν(OSOasym
.
)
3
3
1277, ν(CFsym) 1252, ν(CFasym) 1157, ν(OSOsym) 1031 cm-1. 1H
NMR (200 MHz, CD3NO2): δ 5.86 (br s, 2 H, dCHCHd of five-
membered ring), 5.54 (br s, 2 H, CHdCHC of five-membered
ring), 2.40 (m, 6 H, PCHCH3), 1.38 (dd, 3J(P,H) = 14.1, 3J(H,
H) = 7.0 Hz, 18 H, PCHCH3), 1.36 (dd, 3J(P,H) = 14.1, 3J(H,
H) = 7.0 Hz, 18 H, PCHCH3), 1.19 (br s, 6 H, dCCH3). 13C
NMR (50.3 MHz, CD3NO2): δ 130.5 (s, dCCH3), 130.4 (m,
PCHCH3), 1.15 (dd, J(P,H) = 13.8, J(H,H) = 7.3 Hz, 9 H,
PCHCH3). 13C NMR (100.6 MHz, CD2Cl2): δ 120.7 (q, 1J(F,C) =
320.5 Hz, CF3), 97.0 (d, J(Rh,C) = 5.3 Hz, CHCHCH2 of
1
1
2
allylic system), 91.1 (dd, J(Rh,C) = 8.4, J(P,C) = 6.4 Hz,
CHCHCH2 of allylic system), 69.9 (dd, 1J(Rh,C) =6.1, 2J(P,C) =
3.8 Hz, CHCHCH2 of allylic system), 29.2 (s, CH2 next to the
allylic system), 27.1 (d, 1J(P,C) = 18.3 Hz, PCHCH3), 19.8, 19.6
(both s, PCHCH3). 19F NMR (376.4 MHz, CD2Cl2): δ -78.8 (s).
31P NMR (162.0 MHz, CD2Cl2): δ 40.1 (d, 1J(Rh,P) = 170.4 Hz).
Preparation of [Rh(η3:η3-C8H12){K1-OS(O)2CF3}(PCy3)]
(20). This compound was prepared as described for 19 from 6a
(493 mg, 0.77 mmol) in dichloromethane (10 mL). Time of
reaction: 3 h. A red solid was obtained: yield 365 mg (74%); mp
123 °C dec. ΛM = 71 cm2 Ω-1 mol-1. Anal. Calcd for C27H45-
F3O3PRhS: C, 50.62; H, 7.08; S, 5.00. Found: C, 49.94; H, 6.98;
S, 4.87. IR (CH2Cl2): ν(OSOasym) 1260 br, ν(CFsym) 1253,
1
-C- of five-membered ring), 122.5 (q, J(F,C) = 321.4 Hz,
CF3), 91.9 (d, 1J(Rh,C) = 7.1 Hz, dCHCHd of five-membered
ring), 77.3 (dt, 1J(Rh,C) = 1J(P,C) = 4.1 Hz, CHdCHC of five-
membered ring), 29.7 (vt, N = 19.4 Hz, PCHCH3), 24.8
(s, dCCH3), 21.5, 20.7 (both s, PCHCH3). 19F NMR (188.2
MHz, CD3NO2): δ -78.6 (s). 31P NMR (81.0 MHz, CD3NO2): δ
52.4.2 (d, 1J(Rh,P) = 188.2 Hz).
Generation of cis,cis,trans-[Rh{K2-O2S(O)CF3}(H)2(PiPr3)2]
(17). A solution of 15 (23 mg, 0.04 mmol) in CD2Cl2 (0.5 mL)
was stored in an NMR tube for 12 h at room temperature. A
slow change of color from red to orange and finally to pale
yellow occurred. After the H NMR signals of 15 had disap-
peared, only those of 17 and free benzene could be detected. For
analytical and spectroscopic data of 17 see ref 8a.
1
ν(CFasym) 1161, ν(OSOsym) 1031 cm-1. H NMR (400 MHz,
CD2Cl2):δ5.25 (ddd, 3J(H,H) = 11.3, 3J(H,H) =10.6, 3J(H,H) =
7.0 Hz, 2 H, CHCHCH2 of allylic system), 4.82 (dd, 3J(H,H) = 7.0,
4J(H,H) = 1.4 Hz, 2 H, cis-disposed H of allylic CH2), 4.21 (dd,
1
3
3J(H,H) = 10.6, J(H,H) = 3.2 Hz, 2 H, CHCHCH2 of allylic
Preparation of [Rh{anti-η3-(Cy3PCH2)CHCHCH2}(PCy3)2]-
CF3SO3 (18). A solution of 2 (45 mg, 0.12 mmol) in acetone (10
mL) was treated with PCy3 (118 mg, 0.42 mmol) and stirred for
15 min at room temperature. After the solution was concen-
trated to ca. 2 mL in vacuo, pentane (30 mL) was added. A
yellow air-sensitive solid was formed, which was filtered, washed
three times with pentane (5 mL each), and dried in vacuo: yield
system), 2.99 (dd, 3J(H,H) = 11.3, 3J(P,H) = 6.3 Hz, 2 H, trans-
disposed H of allylic CH2), 2.32(m, 5H, CHofC6H11 and one H of
CH2 next to the allylic system), 2.0-1.1 (br m, 32 H, CH2 of C6H11
and one H of CH2 next to the allylic system). 13C NMR (100.6
1
MHz, CD2Cl2): δ 120.8 (q, J(F,C) = 321.5 Hz, CF3), 97.4 (d,
1J(Rh,C) = 5.1 Hz, CHCHCH2 of allylic system), 92.7 (dd, 1J(Rh,
C) = 9.1, 2J(P,C) = 7.1 Hz, CHCHCH2 of allylic system), 70.1
(dd, 1J(Rh,C) = 6.6, 2J(P,C) = 3.6 Hz, CHCHCH2 of ally-
110 mg (80%); mp 132 °C dec. Anal. Calcd for C59H105
F3O3P3RhS: C, 61.76; H, 9.22; S, 2.80. Found: C, 61.50; H,
-
1
lic system), 37.0 (d, J(P,C) = 17.3 Hz, CH of C6H11), 30.5 (d,

Article
Organometallics, Vol. 29, No. 21, 2010 5657
3J(P,C) = 2.0 Hz, β-CH2 of C6H11), 29.3 (s, CH2 next to the ally-
lic system), 28.1 (d, 2J(P,C) = 9.2 Hz, R-CH2 of C6H11), 28.0 (d,
2J(P,C) = 8.1 Hz, R-CH2 of C6H11), 26.5 (s, γ-CH2 of C6H11).
19F NMR (376.4 MHz, CD2Cl2): δ -78.7 (s). 31P NMR (162.0
MHz, CD2Cl2): δ 28.1 (d, 1J(Rh,P) = 167.8 Hz).
system), 28.0 (d, 2J(P,C) = 11.0 Hz, R-CH2 of C6H11), 27.9 (d,
2J(P,C) = 10.5 Hz, R-CH2 of C6H11), 26.5, 26.4 (both s, γ-CH2
of C6H11). 19F NMR (376.4 MHz, CD2Cl2): δ -78.7 (s). 31P
NMR (121.5 MHz, CD2Cl2): δ 28.8 (d, 1J(Rh,P) = 164.0 Hz).
Preparation of [Rh{η2:η3-CH2dCHCH(PiPr3)(CH2)2CHC-
HCH2}(PiPr3)]B(Arf)4 (23). A solution of 21 (274 mg, 0.22
mmol) in diethyl ether (10 mL) was treated at 0 °C with PiPr3
(43 μL, 0.22 mmol). After it was warmed to room temperature,
the solution was stirred for 15 min. A change of color from red to
orange occurred. The solvent was reduced in vacuo, and the oily
residue was washed twice with pentane (5 mL each). After the
residue was stored for 12 h at 0 °C, an orange-yellow, air-
sensitive solid was obtained: yield 305 mg (98%); mp 35 °C dec.
Anal. Calcd for C58H66BF24P2Rh: C, 49.95; H, 4.77; F, 32.69; P,
4.44. Found: C, 49.70; H, 4.79; F, 32.46; P, 4.30. 1H NMR (400
MHz, CD2Cl2): δ 7.75 (m, 8 H, o-H of Arf), 7.59 (s, 4 H, p-H of
Arf), 4.40 (m, 1 H, CHCHCH2 of allylic system), 3.53 (dd, 3J(H,
H) = 3J(P,H) = 7.2 Hz, 1 H, cis-disposed H of allylic CH2), 3.02
(m, 1 H, CHdCH2 of vinyl unit), 2.97 (dsept, 2J(P,H) = 13.5,
3J(H,H) = 7.0 Hz, 3 H, PCHCH3 of PiPr3 bound to C), 2.88 (m,
1 H, CHCHCH2 of allylic system), 2.85 (m, 1 H, cis-disposed H
of vinylic CH2), 2.49 (m, 3 H, PCHCH3 of PiPr3 bound to Rh),
2.36, 2.16 (both m, 1 H each, CH2CHPiPr3), 2.15 (d, 3J(H,H) =
11.4 Hz, 1 H, trans-disposed H of allylic CH2), 2.01 (d, 3J(H,H) =
12.3 Hz, 1 H, trans-disposed H of vinylic CH2), 1.76 (dd, 2J(P,H) =
12.4, 3J(H,H) = 11.3 Hz, 1 H, CHPiPr3), 2.36, 1.63 (both m, 2 H
each, CH2 next to the allylic system), 1.45, 1.40 (both dd, 3J(P,H) =
15.0, 3J(H,H) = 7.3 Hz, 9 H each, PCHCH3 of PiPr3 bound to
C), 1.34, 1.22 (both m, 1 H each, CH2 next to the allylic system),
1.18, 1.15 (both dd, 3J(P,H) = 12.9, 3J(H,H) = 7.2 Hz, 9 H each,
PCHCH3 of PiPr3 bound to Rh). 13C NMR (100.6 MHz,
Preparation of [Rh(η3:η3-C8H12)(PiPr3)]B(Arf)4 (21). (a) A
solution of 5b (242 mg, 0.20 mmol) in dichloromethane (10 mL)
was heated under reflux for 12 h. A change of color from orange
to deep red occurred. After the reaction mixture was cooled to
room temperature, the solvent was removed in vacuo. The oily
residue was washed three times with pentane (5 mL each) and
the resulting red solid recrystallized from ether/pentane (1:5):
yield 167 mg (69%).
(b) A solution of 19 (100 mg, 0.19 mmol) in dichloromethane
(20 mL) was treated at 0 °C with NaB(Arf)4 (170 mg, 0.19
mmol). After it was warmed to room temperature, the solution
was stirred for 1 h. An off-white solid precipitated. The solution
was decanted from the precipitate and then concentrated to ca. 2
mL in vacuo. Addition of pentane (30 mL) led to the formation
of a red solid, which was filtered, washed three times with
pentane (5 mL each), and dried in vacuo: yield 213 mg (90%);
mp 110 °C dec. ΛM = 63 cm2 Ω-1 mol-1. Anal. Calcd for C49-
1
H45BF24PRh: C, 47.67; H, 3.67. Found: C, 47.78; H, 3.46. H
NMR (200 MHz, CD2Cl2): δ 7.76 (m, 8 H, o-H of Arf), 7.60 (br s,
4 H, p-H of Arf), 5.23 (ddd, 3J(H,H) = 11.5, 3J(H,H) = 10.8,
3J(H,H) = 6.9 Hz, 2 H, CHCHCH2 of allylic system), 4.88 (d,
3J(H,H) = 6.9 Hz, 2 H, cis-disposed H of allylic CH2), 4.23 (dd,
3J(H,H) = 10.8, 3J(H,H) = 3.5 Hz, 2 H, CHCHCH2 of allylic
system), 2.97 (dd, 3J(H,H) = 11.6, 3J(P,H) = 6.4 Hz, 2 H, trans-
disposed H of allylic CH2), 2.62 (m, 3 H, PCHCH3), 2.36, 1.63
(both m, 2 H each, CH2 next to the allylic system), 1.27 (dd, 3J(P,
H) = 14.8, 3J(H,H) = 7.1 Hz, 9 H, PCHCH3), 1.13 (dd,
3J(P,H) = 14.4, 3J(H,H) = 7.1 Hz, 9 H, PCHCH3). 13C
1
CD2Cl2): δ 162.2 (q, J(B,C) = 49.9 Hz, ipso-C of Arf), 135.2
(br s, o-C of Arf), 129.3 (qq, 2J(F,C) = 31.5, 4J(F,C) = 2.9 Hz,
1
1
NMR (100.6 MHz, CD2Cl2): δ 162.2 (q, J(B,C) = 49.9 Hz,
m-C of Arf), 125.0 (q, J(F,C) = 272.4 Hz, CF3), 117.9 (sept,
ipso-C of Arf), 135.3 (br s, o-C of Arf), 129.3 (qq, 2J(F,C) = 31.4,
4J(F,C) = 2.8 Hz, m-C of Arf), 125.0 (q, 1J(F,C) = 272.5 Hz,
CF3), 117.9 (m, p-C of Arf), 98.4 (d, 1J(Rh,C) = 4.6 Hz,
3J(F,C) = 3.8 Hz, p-C of Arf), 100.1 (dd, 1J(Rh,C) = 4.6, 2J(P,
C) = 1.5 Hz, CHCHCH2 of allylic system), 68.4 (ddd, 1J(Rh,C) =
15.6, 2J(P,C) = 6.1, 2J(P0,C) = 1.4 Hz, CHdCH2 of vinyl unit),
55.6 (ddd, 1J(Rh,C) = 11.1, 2J(P,C) = 4.4, 2J(P0,C) = 2.3 Hz,
CHCHCH2 of allylic system), 45.8 (ddd, 1J(Rh,C) = 8.3, 2J(P,
C) = 2J(P0,C) = 2.9Hz, CH2 of allylic system), 36.4 (d, 1J(P,C) =
27.6 Hz, CHPiPr3), 33.3 (d, 3J(P,C) = 4.4 Hz, CH2 next to the
1
2
CHCHCH2 of allylic system), 98.3 (dd, J(Rh,C) = 8.3, J(P,
C) = 5.5 Hz, CHCHCH2 of allylic system), 69.6 (dd, 1J(Rh,C) =
6.0, 2J(P,C) = 4.2 Hz, CH2 of allylic system), 29.6 (s, CH2 next
1
to the allylic system), 27.4 (d, J(P,C) = 19.4 Hz, PCHCH3),
20.0, 20.1 (both s, PCHCH3). 19F NMR (188.2 MHz, CD2Cl2): δ
-63.1 (s). 31P NMR (81.0 MHz, CD2Cl2): δ 42.0 (d, 1J(Rh,P) =
165.3 Hz).
1
2
allylic system), 31.6 (dd, J(Rh,C) = 11.6, J(P,C) = 1.4 Hz,
CH2 of vinyl unit), 26.6 (d, J(P,C) = 17.4 Hz, PCHCH3 of
1
1
PiPr3 bound to Rh), 21.8 (d, J(P,C) = 39.2 Hz, PCHCH3 of
Preparation of [Rh(η3:η3-C8H12)(PCy3)]B(Arf)4 (22). This
compound was prepared as described for 21, either following
method a from 6b (360 mg, 0.27 mmol; time of reaction 3 h) or
following method b from 20 (78 mg, 0.12 mmol) and NaB(Arf)4
(108 mg, 0.12 mmol). A red solid was obtained: yield 284 mg
(69%) from method a and 145 mg (88%) from method b; mp
115 °C dec. ΛM = 48 cm2 Ω-1 mol-1. Anal. Calcd for C58H57-
PiPr3 bound to C), 20.2, 19.8 (both s, PCHCH3 of PiPr3 bound
to Rh), 17.5, 17.4 (both d, 2J(P,C) = 3.6 Hz, PCHCH3 of PiPr3
2
bound to C), 16.7 (d, J(P,C) = 2.9 Hz, CH2CHPiPr3). 19F
NMR (376.4 MHz, CD2Cl2): δ -62.7 (s). 31P NMR (162.0
MHz, CD2Cl2): δ 51.8 (dd, 1J(Rh,P) = 168.7, 4J(P,P) = 9.3 Hz,
RhPiPr3), 39.2 (dd, 3J(Rh,P) = 7.6, 4J(P,P) = 9.3 Hz, CPiPr3).
Preparation of [RhCl(η4-C4H6)(PiPr3)] (24). A solution of 5a
(134 mg, 0.26 mmol) in acetone (10 mL) was treated with NaCl
(100 mg, 1.71 mmol) and stirred for 2 h at room temperature. An
off-white solid precipitated, which was filtered, and the filtrate
was brought to dryness in vacuo. The oily residue was recrys-
tallized from diethyl ether at -20 °C to give a microcrystalline
red solid: yield 72 mg (79%); mp 74 °C dec. Anal. Calcd for
C13H27ClPRh: C, 44.27; H, 7.72. Found: C, 44.03; H, 7.56. MS
(EI): m/z 353 (Mþ), 316 (Mþ - Cl), 299 (Mþ - C4H6), 263 (Mþ
- Cl - C4H6). 1H NMR (400 MHz, CD2Cl2): δ 5.10 (br s, 2 H,
CH2dCHCHdCH2), 3.21 (br s, 2 H, H of CH2 cis to dCH),
2.39 (m, 3 H, PCHCH3), 1.83 (br s, 2 H, H of CH2 trans
1
BF24O3PRh: C, 51.42; H, 4.24. Found: C, 51.62; H, 4.34. H
NMR (300 MHz, CD2Cl2): δ 7.76 (m, 8 H, o-H of Arf), 7.60 (s,
4 H, p-H of Arf), 5.24 (ddd, 3J(H,H) = 11.5, 3J(H,H) = 10.9,
3J(H,H) = 7.0 Hz, 2 H, CHCHCH2 of allylic system), 4.84 (dd,
3J(H,H) = 7.0, 4J(H,H) = 1.3 Hz, 2 H, cis-disposed H of allylic
CH2), 4.21 (dd, 3J(H,H) = 10.9, 3J(H,H) = 3.5 Hz, 2 H,
3
3
CHCHCH2 of allylic system), 2.95 (dd, J(H,H) = 11.5, J(P,
H) = 6.3 Hz, 2 H, trans-disposed H of allylic CH2), 2.35 (m, 5 H,
CH of C6H11 and one H of CH2 next to the allylic system),
2.1-1.1 (br m, 32 H, CH2 of C6H11 and one H of CH2 next to the
allylic system). 13C NMR (75.5 MHz, CD2Cl2): δ 162.2 (q, 1J(B,
C) = 49.8 Hz, ipso-C of Arf), 135.2 (br s, o-C of Arf), 129.3 (qq,
2J(F,C) = 31.5, 4J(F,C) =2.8Hz, m-C of Arf), 125.0 (q, 1J(F,C) =
272.6 Hz, CF3), 117.9 (sept, 3J(F,C) = 3.9 Hz, p-C of Arf), 98.4
(d, 1J(Rh,C) = 5.3 Hz, CHCHCH2 of allylic system), 97.8 (dd,
1J(Rh,C) = 8.7, 2J(P,C) = 6.0 Hz, CHCHCH2 of allylic
3
3
to dCH), 1.27 (dd, J(P,H) = 13.6, J(H,H) = 7.2 Hz, 18 H,
PCHCH3). 31P NMR (162.0 MHz, CD2Cl2):δ48.5 (d, 1J(Rh,P) =
172.9 Hz).
Preparation of [RhBr(η4-C4H6)(PiPr3)] (25). This compound
was prepared as described for 24 from 5a (201 mg, 0.39 mmol)
and NaBr (250 mg, 2.10 mmol) in acetone (10 mL). A red solid
was obtained: yield 118 mg (76%); mp 70 °C dec. Anal. Calcd for
C13H27BrPRh: C, 39.32; H, 6.85. Found: C, 39.00; H, 6.79. 1H
1
2
system), 70.0 (dd, J(Rh,C) = 6.3, J(P,C) = 4.2 Hz, CH2 of
allylic system), 37.3 (d, 1J(P,C) = 18.4 Hz, CH of C6H11), 31.1,
31.0 (both s, β-CH2 of C6H11), 29.5 (s, CH2 next to the allylic

5658 Organometallics, Vol. 29, No. 21, 2010
Bosch and Werner
NMR (400 MHz, CD2Cl2): δ 5.10 (br s, 2 H, CH2d
CHCHdCH2), 3.35 (br d, J(H,H) = 5.0 Hz, 2 H, H of CH2
MHz, CD2Cl2): δ 121.3 (q, 1J(F,C) = 321.3 Hz, CF3), 107.5 (d,
1J(Rh,C) = 3.8 Hz, CHCH3), 48.7 (d, 1J(Rh,C) = 9.5 Hz, CH2),
3
cis to dCH), 2.44 (m, 3 H, PCHCH3), 1.82 (br d, 3J(H,H) = 10.0
Hz, 2 H, H of CH2 trans to dCH), 1.27 (dd, J(P,H) = 13.5,
27.6 (d, J(Rh,C) = 2.0 Hz, AsCHCH3), 20.9 (s, AsCHCH3),
2
3
17.7 (s, dCCH3). 19F NMR (376.4 MHz, CD2Cl2): δ -78.7 (s).
Preparation of [Rh(s-cis-η4-C4H6)2(SbiPr3)]CF3SO3 (29).
This compound was prepared as described for 26 from 2 (78
mg, 0.08 mmol) and SbiPr3 (17 μL, 0.08 mmol). A colorless solid
was obtained: yield 92 mg (91%); mp 137 °C dec. Anal. Calcd for
C18H33F3O3RhSSb: C, 35.37; H, 5.44; S, 5.25. Found: C, 35.37;
H, 5.33; S, 5.34. IR (CH2Cl2): ν(OSOasym) and ν(CFsym) 1260 br,
3J(H,H) = 7.3 Hz, 18 H, PCHCH3). 13C NMR (100.6 MHz,
CD2Cl2): δ 90.0 (br s, CH2dCHCHdCH2), 54.0 (br s,
CH2dCHCHdCH2), 25.3 (d, J(P,C) = 21.0 Hz, PCHCH3),
1
20.1 (s, PCHCH3). 31P NMR (162.0 MHz, CD2Cl2): δ 48.7 (d,
1J(Rh,P) = 173.0 Hz).
Preparation of [Rh(s-cis-η4-C4H6)2(AsiPr3)]CF3SO3 (26). A
solution of 2 (128 mg, 0.33 mmol) in acetone (10 mL) was treated
with AsiPr3 (65 μL, 0.33 mmol). After the solution was stirred
for 15 min at room temperature, it was concentrated to ca. 3 mL
in vacuo. Addition of pentane (20 mL) led to the formation of a
colorless solid, from which the solution was decanted. The solid
residue was washed four times with pentane (5 mL each) and
dried in vacuo: yield 166 mg (88%); mp 125 °C dec. Anal. Calcd
for C18H33AsF3O3RhS: C, 38.31; H, 5.89; S, 5.68. Found: C,
1
ν(CFasym) 1151, ν(OSOsym) 1031 cm-1. H NMR (200 MHz,
CD2Cl2): δ 5.83 (m, 4 H, CH2dCHCHdCH2), 2.97 (br d, 3J(H,
H) = 6.9 Hz, 4 H, H of CH2 cis to dCH), 2.73 (sept, 3J(H,H) =
3
7.4 Hz, 3 H, SbCHCH3), 1.51 (d, J(H,H) = 7.4 Hz, 18 H,
SbCHCH3), 1.49 (br d, 3J(H,H) = 9.9 Hz, 4 H, 4 H, H of CH2
trans to dCH). 13C NMR (50.3 MHz, CD2Cl2): δ 121.2 (q, 1J(F,
C) = 320.8 Hz, CF3), 87.9 (d, 1J(Rh,C) = 4.6 Hz, CH2dCHC-
1
HdCH2), 45.4 (d, J(Rh,C) = 8.3 Hz, CH2dCHCHdCH2),
21.8 (s, SbCHCH3), 21.0 (d, J(Rh,C) = 2.8 Hz, SbCHCH3).
2
38.09; H, 5.75; S, 5.78. IR (CH2Cl2): ν(OSOasym) and ν(CFsym
)
1260 br, ν(CFasym) 1152, ν(OSOsym) 1033 cm-1. 1H NMR (400
MHz, CD2Cl2): δ 5.86 (m, 4 H, CH2dCHCHdCH2), 3.16 (br d,
3J(H,H) = 7.5 Hz, 4 H, H of CH2 cis to dCH), 2.69 (sept, 3J(H,
H) = 7.2 Hz, 3 H, AsCHCH3), 1.47 (br d, 3J(H,H) = 9.7 Hz, 4
H, H of CH2 trans to dCH), 1.44 (d, 3J(H,H) = 7.2 Hz, 18 H,
AsCHCH3). 13C NMR (100.6 MHz, CD2Cl2): δ 121.3 (q, 1J(F,
C) = 321.1 Hz, CF3), 90.0 (d, 1J(Rh,C) = 3.6 Hz, CH2d
CHCHdCH2), 49.9 (d, 1J(Rh,C) = 8.0 Hz, CH2dCHCHd
CH2), 28.7(d, 2J(P,C) = 2.2Hz, AsCHCH3), 20.8(s, AsCHCH3).
19F NMR (376.4 MHz, CD2Cl2): δ -78.7 (s).
19F NMR (188.2 MHz, CD2Cl2): δ -79.1 (s).
Preparation of [Rh(s-cis-η4-C4H5Me)2(SbiPr3)]CF3SO3 (30).
This compound was prepared as described for 26 from 3 (96 mg,
0.25 mmol) and SbiPr3 (53 μL, 0.25 mmol). A colorless solid was
obtained, which according to the 1H and 13C NMR spectra
consists of a 6:1 mixture of the anti and syn isomers: yield 154 mg
(97%); mp 132 °C dec. Anal. Calcd for C20H37F3O3RhSSb: C,
37.58; H, 5.83; S, 5.02. Found: C, 37.35; H, 5.76; S, 5.06. IR
(CH2Cl2): ν(OSOasym) and ν(CFsym) 1260 br, ν(CFasym) 1154,
ν(OSOsym) 1031 cm-1. 1H NMR (400 MHz, CD2Cl2): anti iso-
Preparation of [Rh(s-cis-η4-C4H5Me)2(AsiPr3)]CF3SO3 (27).
This compound was prepared as described for 26 from 3 (101
mg, 0.26 mmol) and AsiPr3 (51 μL, 0.26 mmol). A colorless solid
was obtained, which according to the 1H and 13C NMR spectra
consists of a 9:1 mixture of the anti and syn isomers: yield 140 mg
(89%); mp 132 °C dec. Anal. Calcd for C20H37AsF3O3RhS: C,
40.55; H, 6.30; S, 5.41. Found: C, 40.13; H, 6.31; S, 5.56. IR
(CH2Cl2): ν(OSOasym) and ν(CFsym) 1260 br, ν(CFasym) 1151,
3
mer, δ 4.96 (dd, J(H,H) = 9.4 and 7.6 Hz, 2 H, CH2dCH-
CCH3), 3.06 (dd, 3J(H,H) = 7.6, 2J(H,H) = 1.5 Hz, 2 H, H of
CH2 cis to dCH), 2.85 (br s, 2 H, H of CH2 cis to dCCH3), 2.70
(sept, 3J(H,H) = 7.4 Hz, 3 H, SbCHCH3), 2.29 (s, 6 H, dCCH3),
1.51, 1.50 (both d, 3J(H,H) = 7.4 Hz, 9 H each, SbCHCH3), 1.41
(br d, 3J(H,H) = 9.4 Hz, 2 H, H of CH2 trans to dCH), 1.23 (s, 2
H, H of CH2 trans to dCCH3); syn isomer, δ 5.52 (m, 2 H,
CH2dCHCCH3), 2.92 (s, 2 H, H of CH2 cis to dCCH3), 2.81
(dd, 3J(H,H) = 7.2, 2J(H,H) = 1.4 Hz, 2 H, H of CH2 cis
to dCH), other signals of syn isomer not exactly located. 13C NMR
(100.6 MHz, CD2Cl2): anti isomer, δ 121.3 (q, 1J(F,C) = 321.5
Hz, CF3), 107.8 (d, 1J(Rh,C) = 4.1 Hz, CHCH3), 96.0 (d, 1J(Rh,
C) = 4.7 Hz, CHdCH2),44.3(d,1J(Rh,C) =8.1Hz,CH2dCCH3),
42.4 (d, 1J(Rh,C) = 8.1 Hz, CH2dCH), 21.9 (s, dCCH3), 21.8
(s, SbCHCH3), 20.9 (d, 2J(P,C) = 2.0 Hz, SbCHCH3]; syn
isomer, δ 109.5 (d, 1J(Rh,C) = 3.5 Hz, CHCH3), 85.9 (d, 1J(Rh,
ν(OSOsym) 1031 cm-1 1H NMR (400 MHz, CD2Cl2): anti
.
isomer, δ 4.89 (dd, 3J(H,H) = 10.6 and 7.3 Hz, 2 H,
CH2dCHCCH3), 3.22 (dd, 3J(H,H) = 7.3, 2J(H,H) = 1.4 Hz,
2 H, H of CH2 cis to dCH), 3.01 (s, 2 H, H of CH2 cis
to dCCH3), 2.65 (sept, 3J(H,H) = 7.2 Hz, 3 H, AsCHCH3), 2.26
(s, 6 H, dCCH3), 1.43, 1.42 (both d, 3J(H,H) = 7.2 Hz, 9 H each,
AsCHCH3), 1.38 (br d, 3J(H,H) = 10.6 Hz, 2 H, H of CH2 trans
to dCH), 1.21 (s, 2 H, H of CH2 trans to dCCH3); syn isomer, δ
5.51 (m, 2 H, CH2dCHCCH3), 3.11 (s, 2 H, H of CH2 cis
1
C) = 4.5 Hz, CHdCH2), 44.8 (d, J(Rh,C) = 8.1 Hz, CH2d
3
CCH3), 43.0 (d, 1J(Rh,C) = 9.1 Hz, CH2dCH), 22.6 (s, d
CCH3), other signals of syn isomer not exactly located.
19F NMR (376.4 MHz, CD2Cl2): δ -78.6 (s).
to dCCH3), 3.02 (br d, J(H,H) = 7.2 Hz, 2 H, H of CH2 cis
to dCH), other signals of syn isomer not exactly located. 13C
NMR (100.6 MHz, CD2Cl2): anti isomer, δ 121.3 (q, 1J(F,C) =
321.4 Hz, CF3), 110.3 (d, 1J(Rh,C) = 3.6 Hz, CHCH3), 98.0 (d,
Preparation of [Rh(s-cis-η4-C4H4Me2)2(SbiPr3)]CF3SO3 (31).
This compound was prepared as described for 26 from 4 (50 mg,
0.12 mmol) and SbiPr3 (25 μL, 0.12 mmol). A colorless solid was
obtained: yield 76 mg (95%); mp 146 °C dec. Anal. Calcd for
C22H41F3O3RhSSb: C, 39.60; H, 6.19; S, 4.81. Found: C, 39.33;
H, 6.34; S, 4.72. IR (CH2Cl2): ν(OSOasym) and ν(CFsym) 1260 br,
1
1J(Rh,C) = 4.4 Hz, CHdCH2), 48.6 (d, J(Rh,C) = 8.7 Hz,
CH2dCCH3), 46.9 (d, 1J(Rh,C) = 8.0 Hz, CH2dCH), 28.2 (d,
2J(P,C) = 1.4 Hz, AsCHCH3), 22.1 (s, dCCH3), 20.8 (s,
AsCHCH3); syn isomer, δ 112.7 (d, 1J(Rh,C) = 3.6 Hz,
CHCH3), 87.8 (d, 1J(Rh,C) = 4.4 Hz, CHdCH2), 49.8 (d,
1J(Rh,C) = 8.7 Hz, CH2dCCH3), 47.3 (d, 1J(Rh,C) = 8.7
1
ν(CFasym) 1154, ν(OSOsym) 1031 cm-1. H NMR (200 MHz,
2
CD2Cl2): δ 2.79 (d, 2J(H,H) = 1.5 Hz, 4 H, H of CH2 cis to d
CCH3), 2.70 (sept, 3J(H,H) = 7.4 Hz, 3 H, SbCHCH3), 1.93 (s,
12 H, dCCH3), 1.51 (d, 3J(H,H) = 7.4 Hz, 18 H, SbCHCH3),
1.21 (br s, 4 H, H of CH2 trans to dCCH3). 13C NMR (100.6
MHz, CD2Cl2): δ 121.3 (q, 1J(F,C) = 321.3 Hz, CF3), 104.3 (d,
1J(Rh,C) = 3.7 Hz, CHCH3), 43.7 (d, 1J(Rh,C) = 9.2 Hz, CH2),
Hz, CH2dCH), 28.1 (d, J(P,C) = 1.5 Hz, AsCHCH3), other
signals of syn isomer not exactly located. 19F NMR (376.4 MHz,
CD2Cl2): δ -78.7 (s).
Preparation of [Rh(s-cis-η4-C4H4Me2)2(AsiPr3)]CF3SO3 (28).
This compound was prepared as described for 26 from 4 (183
mg, 0.44 mmol) and AsiPr3 (87 μL, 0.44 mmol). A colorless solid
was obtained: yield 228 mg (84%); mp 148 °C dec. Anal. Calcd
for C22H41AsF3O3RhS: C, 42.59; H, 6.66; S, 5.17. Found: C,
2
21.8 (s, SbCHCH3), 20.9 (d, J(Rh,C) = 1.9 Hz, SbCHCH3),
17.4 (s, dCCH3). 19F NMR (376.4 MHz, CD2Cl2): δ -79.2 (s).
Preparation of [Rh(s-cis-η4-C4H6)2(CO)]CF3SO3 (33). A solu-
tion of 32 (320 mg, 0.82 mmol) in dichloromethane (30 mL) was
treated with a solution of CF3SO3Ag (423 mg, 1.64 mmol) in
diethyl ether (10 mL) and stirred for 1 h at room temperature. The
precipitate was filtered, and a stream of butadiene was passed
through the orange-red filtrate for 10 s. A change of color from
42.24; H, 6.36; S, 5.19. IR (CH2Cl2): ν(OSOasym) and ν(CFsym
)
1260 br, ν(CFasym) 1154, ν(OSOsym) 1032 cm-1. 1H NMR (400
MHz, CD2Cl2): δ 2.99 (d, 2J(H,H) = 1.5 Hz, 4 H, H of CH2 cis
to dCCH3), 2.65 (sept, 3J(H,H) = 7.3 Hz, 3 H, AsCHCH3), 1.90
(s, 12 H, dCCH3), 1.43 (d, 3J(H,H) = 7.3 Hz, 18 H, AsCHCH3),
1.21 (br s, 4 H, H of CH2 trans to dCCH3). 13C NMR (100.6

Article
Organometallics, Vol. 29, No. 21, 2010 5659
orange-red to off-white occurred. The solution was concentrated to
ca. 5 mL in vacuo, and pentane (30 mL) was added. A colorless solid
precipitated, from which the solution was decanted. The solid residue
was washed three times with pentane (5 mL each) and dried in vacuo
for 15 min at 0 °C: yield 465 mg (73%); mp 83 °C dec. Anal. Calcd for
C10H12F3O4RhS: C, 30.94; H, 3.12; S, 8.26. Found: C, 30.61; H, 3.00;
S, 8.06. IR (CH2Cl2): ν(CO) 2096, ν(OSOasym) 1260, ν(CFsym) 1250,
4 H, H of CH2 cis to dCCH3), 1.85 (s, 12 H, dCCH3), 1.68 (d,
2J(H,H) = 1.7 Hz, 4 H, H ofCH2 trans to dCCH3), 1.63 (br s, 9 H,
NCCH3). 13C NMR (100.6 MHz, CD2Cl2):
δ 141.6 (dt,
1J(Rh,C) = 71.7, 1J(14N,C) = 17.1 Hz, CN), 121.2 (q, 1J(F,C) =
1
320.9 Hz, CF3), 108.5 (d, J(Rh,C) = 4.1 Hz, CHCH3), 60.1 (t,
1J(14N,C) = 4.6 Hz, NCCH3), 51.4 (d, 1J(Rh,C) = 9.2 Hz,
CH2dCCH3), 30.8 (s, NCCH3), 17.6 (s, dCCH3). 19F NMR
(376.4 MHz, CD2Cl2): δ -78.6 (s).
ν(CFasym) 1163, ν(OSOsym) 1031 cm-1
.
1H NMR (400 MHz,
3
acetone-d6): δ 6.27 (m, 4 H, CH2dCHCHdCH2), 3.63 (d, J(H,
H) = 7.0 Hz, 4 H, H of CH2 cis to dCH), 2.80 (d, 3J(H,H) = 10.0
Hz, 4 H, H of CH2 trans to dCH). 13C NMR (100.6 MHz, acetone-
d6): δ 197.1 (d, 1J(Rh,C) = 77.6 Hz, CO), 121.5 (q, 1J(F,C) = 328.0
Hz, CF3),96.1(d,1J(Rh,C) =3.8Hz,CH2dCHCHdCH2),56.3(d,
1J(Rh,C) = 7.6 Hz, CH2dCHCHdCH2). 19F NMR (376.4 MHz,
acetone-d6): δ -78.4 (s).
Preparation of [Rh(s-cis-η4-C4H6)2(CN-2,6-C6H3iPr2)]CF3-
SO3 (37). This compound was prepared as described for 26
from 2 (57 mg, 0.15 mmol) and CN-2-C6H3iPr2 (40 μL, 0.16
mmol). A colorless solid was obtained: yield 82 mg (95%); mp 69
°C dec. Anal. Calcd for C22H29F3NO3RhS: C, 48.27; H, 5.33; N,
2.55; S, 5.85. Found: C, 47.98; H, 5.02; N, 2.46; S, 5.99. IR
(CH2Cl2): ν(CN) 2172, ν(OSOasym) 1275, ν(CFsym) 1253,
Preparation of (Rh(s-cis-η4-C4H6)2(CNtBu)]CF3SO3 (34).
This compound was prepared as described for 26 from 2 (44
mg, 0.12 mmol) and CNtBu (14 μL, 0.12 mmol). A colorless
solid was obtained: yield 53 mg (98%); mp 67 °C dec. Anal.
Calcd for C14H21F3NO3RhS: C, 37.93; H, 4.77; N, 3.16; S, 7.23.
Found: C, 37.54; H, 4.47; N, 3.47; S, 6.80. IR (CH2Cl2): ν(CN)
2196, ν(OSOasym) 1275, ν(CFsym) 1255, ν(CFasym) 1170,
ν(CFasym) 1172, ν(OSOsym) 1031 cm-1. H NMR (200 MHz,
1
CD2Cl2): δ 7.50 (m, 1 H, p-H of C6H3), 7.33 (m, 2 H, m-H of
C6H5), 6.06 (m, 4 H, CH2dCHCHdCH2), 3.38 (d, 3J(H,H) =
7.1 Hz, 4 H, H of CH2 cis to dCH), 3.37 (sept, 3J(H,H) = 6.9
Hz, 2 H, CHCH3), 2.05 (d, 3J(H,H) = 9.9 Hz, 4 H, H of CH2
trans to dCH), 1.37 (d, 3J(H,H) = 6.9 Hz, 6 H, CHCH3). 13
C
NMR (50.3 MHz, CD2Cl2): 145.8 (s, o-C of C6H3), 131.4 (s, p-C
of C6H5), 124.3 (s, m-C of C6H5), 121.4 (q, 1J(F,C) = 321.5 Hz,
CF3), 92.4 (d, 1J(Rh,C) = 3.5 Hz, CH2dCHCHdCH2), 52.4 (d,
1J(Rh,C) = 7.7 Hz, CH2dCHCHdCH2), 30.8 (s, CHCH3),
22.6 (s, CHCH3); signals of ipso-C of C6H3 and CN not exactly
located. 19F NMR (376.4 MHz, CD2Cl2): δ -78.7 (s).
1
ν(OSOsym) 1031 cm-1. H NMR (400 MHz, CD2Cl2): δ 5.85
(m, 4 H, CH2dCHCHdCH2), 3.22 (d, 3J(H,H) = 6.5 Hz, 4 H,
H of CH2 cis to dCH), 1.90 (d, 3J(H,H) = 9.7 Hz, 4 H, H of CH2
trans to dCH), 1.68 (s, CCH3). 13C NMR (100.6 MHz, CD2Cl2):
δ 139.9 (dt, 1J(Rh,C) = 75.3, 1J(14N,C) = 17.8 Hz, CN), 121.3
(q, 1J(F,C) = 321.4 Hz, CF3), 91.7 (d, 1J(Rh,C) = 4.1 Hz,
CH2dCHCHdCH2), 60.3 (t, 1J(14N,C) = 4.6 Hz, CCH3), 52.4
Preparation of [Rh(s-cis-η4-C4H5Me)2(CN-2,6-C6H3iPr2)]-
CF3SO3 (38). This compound was prepared as described for
26 from 3 (85 mg, 0.22 mmol) and CNtBu (25 μL, 0.22 mmol). A
1
(d, J(Rh,C) = 7.1 Hz, CH2dCHCHdCH2), 30.6 (s, CCH3).
19F NMR (376.4 MHz, CD2Cl2): δ -78.7 (s).
colorless solid was obtained, which according to the 1H and 13
C
Preparation of [Rh(s-cis-η4-C4H5Me)2(CNtBu)]CF3SO3 (35).
This compound was prepared as described for 26 from 3 (85 mg,
0.22 mmol) and CNtBu (25 μL, 0.22 mmol). A colorless solid
was obtained, which according to the 1H and 13C NMR spectra
consists of a 4:1 mixture of the anti and syn isomers: yield 95 mg
(92%); mp 101 °C dec. Anal. Calcd for C16H25F3NO3RhS: C,
40.77; H, 5.34; N, 2.97; S, 6.80. Found: C, 40.46; H, 4.97; N,
3.24; S, 6.43. IR (CH2Cl2): ν(CN) 2195, ν(OSOasym) 1275,
NMR spectra consists of a 4:1 mixture of the anti and syn
isomers: yield 95 mg (92%); mp 101 °C dec. Anal. Calcd for
C16H25F3NO3RhS: C, 40.77; H, 5.34; N, 2.97; S, 6.80. Found: C,
40.46; H, 4.97; N, 3.24; S, 6.43. IR (CH2Cl2): ν(CN) 2195,
ν(OSOasym) 1275, ν(CFsym) 1254, ν(CFasym) 1171, ν(OSOsym
)
1
1032 cm-1. H NMR (400 MHz, CD2Cl2): anti isomer, δ 5.04
3
(dd, J(H,H) = 10.6 and 7.4 Hz, 2 H, CH2dCHCCH3), 3.27
(dd, 3J(H,H) = 7.4, 2J(H,H) = 2.0 Hz, 2 H, H of CH2 cis
to dCH), 3.09 (s, 2 H, H of CH2 trans to dCCH3), 2.19 (s, 6
H, dCCH3), 1.82 (d, 3J(H,H) = 10.6 Hz, 2 H, H of CH2 trans
to dCH), 1.65 (br s, 11 H, NCCH3 and H of CH2 cis to dCCH3);
syn isomer, δ 5.57 (m, 2 H, CH2dCHCCH3), 3.16 (s, 2 H, H of
CH2 trans to dCCH3), 3.05 (br d, 3J(H,H) = 7.2 Hz, 2 H, H of
CH2 cis to dCH), 1.95 (s, 6 H, CCH3), 1.67 (br d, 3J(H,H) =
10.6 Hz, 2 H, H of CH2 trans to dCH), 1.51 (br s, 9 H, NCCH3),
1.47 (s, 2 H, H of CH2 cis to dCCH3). 13C NMR (100.6 MHz,
CD2Cl2): anti isomer, δ 139.8 (dt, 1J(Rh,C) = 73.2, 1J(14N,C) =
ν(CFsym) 1254, ν(CFasym) 1171, ν(OSOsym) 1032 cm-1
.
1H
3
NMR (400 MHz, CD2Cl2): anti isomer, δ 5.04 (dd, J(H,H) =
10.6 and 7.4 Hz, 2 H, CH2dCHCCH3), 3.27 (dd, 3J(H,H) = 7.4,
2J(H,H) = 2.0 Hz, 2 H, H of CH2 cis to dCH), 3.09 (s, 2 H, H of
CH2 trans to dCCH3), 2.19 (s, 6 H, dCCH3), 1.82 (d, 3J(H,H) =
10.6 Hz, 2 H, H of CH2 trans to dCH), 1.65 (br s, 11 H, NCCH3
and H of CH2 cis to dCCH3); syn isomer, δ 5.57 (m, 2 H,
CH2dCHCCH3), 3.16 (s, 2 H, H of CH2 trans to dCCH3), 3.05
(br d, 3J(H,H) = 7.2 Hz, 2 H, H of CH2 cis to dCH), 1.95 (s, 6 H,
3
1
CCH3), 1.67 (br d, J(H,H) = 10.6 Hz, 2 H, H of CH2 trans
17.0 Hz, CN), 121.4 (q, J(F,C) = 321.5 Hz, CF3), 111.8 (d,
1J(Rh,C) = 4.1 Hz, CHCH3), 98.9 (d, 1J(Rh,C) = 5.1 Hz, CHd
CH2), 60.2 (t, 1J(14N,C) = 4.6 Hz, NCCH3), 51.4 (d, 1J(Rh,C) =
to dCH), 1.51 (br s, 9 H, NCCH3), 1.47 (s, 2 H, H of CH2 cis
to dCCH3). 13C NMR (100.6 MHz, CD2Cl2): anti isomer, δ 139.8
(dt, 1J(Rh,C) = 73.2, 1J(14N,C) = 17.0 Hz, CN), 121.4 (q, 1J(F,
C) = 321.5 Hz, CF3), 111.8 (d, 1J(Rh,C) = 4.1 Hz, CHCH3),
98.9 (d, 1J(Rh,C) = 5.1 Hz, CHdCH2), 60.2 (t, 1J(14N,C) = 4.6
1
8.1 Hz, CH2dCCH3), 49.5 (d, J(Rh,C) = 8.1 Hz, CH2dCH),
30.6 (s, NCCH3), 21.9 (s, dCCH3); syn isomer, δ 113.0 (d, 1J(Rh,
C) = 3.9 Hz, CHCH3), 90.1 (d, 1J(Rh,C) = 4.8 Hz, CHdCH2),
58.5 (t, 1J(14N,C) = 5.0 Hz, NCCH3), 52.0(d, 1J(Rh,C) = 8.5Hz,
1
Hz, NCCH3), 51.4 (d, J(Rh,C) = 8.1 Hz, CH2dCCH3), 49.5
(d, 1J(Rh,C) = 8.1 Hz, CH2dCH), 30.6 (s, NCCH3), 21.9
(s, dCCH3); syn isomer, δ 113.0 (d, 1J(Rh,C) = 3.9 Hz, CHCH3),
90.1 (d, 1J(Rh,C) = 4.8 Hz, CHdCH2), 58.5 (t, 1J(14N,C) = 5.0
1
CH2dCCH3), 50.1 (d, J(Rh,C) = 9.1 Hz, CH2dCH), 30.4 (s,
NCCH3), 20.3 (s, dCCH3), other signals of syn isomer not exactly
located. 19F NMR (376.4 MHz, CD2Cl2): δ -78.7 (s).
1
Preparation of [Rh(s-cis-η4-C4H4Me2)2(CN-2,6-C6H3iPr2)]-
CF3SO3 (39). This compound was prepared as described for
26 from 4 (76 mg, 0.18 mmol) and CN-2,6-C6H3iPr2 (42 μL, 0.18
mmol). A colorless solid was obtained: yield 108 mg (98%); mp
120 °C dec. Anal. Calcd for C26H35F3NO3RhS: C, 51.91; H,
5.86; N, 2.32; S, 5.33. Found: C, 51.57; H, 5.68; N, 2.45; S, 5.12.
IR (CH2Cl2): ν(CN) 2163, ν(OSOasym) 1278, ν(CFsym) 1253,
Hz, NCCH3), 52.0 (d, J(Rh,C) = 8.5 Hz, CH2dCCH3), 50.1
(d, 1J(Rh,C) = 9.1 Hz, CH2dCH), 30.4 (s, NCCH3), 20.3
(s, dCCH3), other signals of syn isomer not exactly located.
19F NMR (376.4 MHz, CD2Cl2): δ -78.7 (s).
Preparation of [Rh(s-cis-η4-C4H4Me2)2(CNtBu)]CF3SO3 (36).
This compound was prepared as described for 26 from 4 (142 mg,
0.34 mmol) and CNtBu (42 μL, 0.35 mmol). A colorless solid was
obtained: yield 138 mg (81%); mp 130 °C dec. Anal. Calcd for
C18H29F3NO3RhS: C, 43.29; H, 5.85; N, 2.80; S, 6.42. Found: C,
42.90; H, 5.42; N, 2.82; S, 6.25. IR (CH2Cl2): ν(CN) 2190,
ν(OSOasym) 1275, ν(CFsym) 1250, ν(CFasym) 1171, ν(OSOsym) 1031
cm-1. 1H NMR (400 MHz, CD2Cl2): δ 3.03 (d, 2J(H,H) = 1.7 Hz,
1
ν(CFasym) 1170, ν(OSOsym) 1031 cm-1. H NMR (400 MHz,
CD2Cl2): δ 7.48 (m, 1 H, p-H of C6H3), 7.31 (m, 2 H, m-H of
C6H5), 3.31 (sept, J(H,H) = 7.0 Hz, 2 H, CHCH3), 3.21 (d,
3
2J(H,H) = 1.4 Hz, 4 H, H of CH2 cis to dCCH3), 1.94 (s,
12 H, dCCH3), 1.84 (s, 4 H, H of CH2 trans to dCCH3), 1.35 (d,

5660 Organometallics, Vol. 29, No. 21, 2010
Bosch and Werner
3J(H,H) = 7.0 Hz, 12 H, CHCH3). 13C NMR (100.6 MHz,
CD2Cl2): 145.7 (s, o-C of C6H3), 131.3 (s, p-C of C6H5), 124.3 (s,
6H, C6H6), 2.00 (m, 4 H, PCHCH3), 1.72(m, 2H, PCH2CH2), 1.61
(m, 4 H, PCH2CH2), 1.2 (br m, 24 H PCHCH3). 31P NMR (81.0
MHz, CD2Cl2): δ 47.9 (d, 1J(Rh,P) = 189.9 Hz).
1
m-C of C6H5), 121.3 (q, J(F,C) = 321.4 Hz, CF3), 109.3 (d,
1J(Rh,C) = 3.0 Hz, dCCH3), 51.0 (d, 1J(Rh,C) = 9.1 Hz,
CH2dC), 30.7 (s, CHCH3), 22.6 (s, CHCH3), 17.4 (s, dCCH3);
signals of ipso-C of C6H3 and CN not exactly located. 19F NMR
(376.4 MHz, CD2Cl2): δ -79.1 (s).
Preparation of [Rh(η4-C4H6){K2-iPr2P(CH2)3PiPr2}(PMe3)]-
CF3SO3 (43a,b). A solution of 40 (105 mg, 0.18 mmol) in
dichloromethane (20 mL) was treated with PMe3 (18 μL, 0.18
mmol) at -30 °C. A quick change of color from red to orange
occurred. After the solution was warmed to room temperature,
it was stirred for 30 min. The reaction mixture was concentrated
to ca. 3 mL in vacuo, and pentane (15 mL) was added. A yellow
suspension was formed; after it was stored for 30 min, a yellow
solid precipitated. The solution was decanted, and the solid
residue was washed three times with pentane (5 mL each) and
dried in vacuo. According to the NMR spectra it consists of a ca.
7:1 mixture of the basal and apical isomers 43a,b: yield 102 mg
(86%); mp 76 °C dec. Anal. Calcd for C23H49F3O3P3RhS: C,
41.95; H, 7.50; S, 4.87. Found: C, 41.69; H, 7.30; S, 4.64. IR
Preparation of [Rh(η4-C4H6){K2-iPr2P(CH2)3PiPr2}]CF3SO3
(40). A solution of 2 (210 mg, 0.54 mmol) in dichloromethane
(20 mL) was treated with 1,3-C3H6(PiPr2)2 (168 μL, 0.54 mmol)
at -10 °C. After the solution was warmed to room temperature,
it was stirred for 30 min. A change of color from light orange to
red occurred. The reaction mixture was concentrated to ca. 3 mL
in vacuo, and pentane (15 mL) was added. A red solid pre-
cipitated, from which the solution was decanted. The solid
residue was washed three times with pentane (5 mL each) and
dried in vacuo: yield 299 mg (95%); mp 104 °C dec. Anal. Calcd
for C20H40F3O3P2RhS: C, 41.24; H, 6.92; S, 5.50. Found: C,
(CH2Cl2): ν(OSOasym) and ν(CFsym) 1270-1250 br, ν(CFasym
)
1155, ν(OSOsym) 1030 cm-1. 1H NMR (400 MHz, CD2Cl2); 43a,
δ 5.78, 5.14 (both br s, 1 H each, dCHCHd), 2.60 (m, 2 H, one H
of dCHCH2 cis to dCH and one H of PCHCH3), 2.50, 2.37
(both m, 2 H, PCHCH3), 2.28 (br s, 1 H, one H of dCHCH2 cis
to dCH), 2.21 (m, 3 H, PCHCH3 and PCH2CH2), 2.01, 1.61
(both m, 4 H, PCH2CH2), 1.40 (d, 2J(P,H) = 7.9 Hz, 9 H,
PCH3), 1.36-1.15 (br m, 24 H, PCHCH3), 1.06, 0.71 (both m, 1
H each, H of dCHCH2 trans to dCH); 43b, δ 5.84 (m,
2 H, dCHCHd), 1.62 (d, 2J(P,H) = 7.9 Hz, 9 H, PCH3), 0.37 (m,
2 H, H of dCHCH2 trans to dCH), other signals not exactly located.
13CNMR(100.6MHz,CD2Cl2):43a,δ120.9 (q, 1J(F,C) =321.0 Hz,
CF3), 86.5, 86.0 (both br s, dCHCHd), 39.5 (ddd, 1J(Rh,C) = 6.2,
40.95; H, 6.58; S, 5.43. IR (CH2Cl2): ν(OSOasym) and ν(CFsym
)
1270-1250 br, ν(CFasym) 1154, ν(OSOsym) 1030 cm-1. 1H NMR
(400 MHz, CD2Cl2): δ 5.50 (m, 2 H, CH2dCHCHdCH2), 4.34
(m, 2 H, H of CH2 cis to dCH), 2.75 (d, 3J(H,H) = 13.5 Hz, 2 H,
H of CH2 trans to dCH), 2.43 (m, 2 H, PCHCH3), 2.06 (br m, 4
H PCHCH3 and PCH2CH2), 1.66 (m, 4 H, PCH2CH2), 1.32 (dd,
3
3J(P,H) = 17.4, J(H,H) = 7.2 Hz, 6 H, PCHCH3), 1.22 (dd,
3
3J(P,H) = 12.9, J(H,H) = 7.0 Hz, 6 H, PCHCH3), 1.08 (dd,
3
3J(P,H) = 15.9, J(H,H) = 7.2 Hz, 6 H, PCHCH3), 1.07 (dd,
3J(P,H) = 15.3, 3J(H,H) = 6.9 Hz, 6 H, PCHCH3). 13C NMR
1
(100.6 MHz, CD2Cl2): δ 121.3 (q, J(F,C) = 321.8 Hz, CF3),
99.9 (d, 1J(Rh,C) = 5.5 Hz, CH2dCHCHdCH2), 63.6 (dt,
2
1J(Rh,C) = 6.2, J(P,C) = 4.9 Hz, CH2dCHCHdCH2), 30.9
1
2J(P,C) = 37.4 and 7.6 Hz, CHdCH2), 37.7 (ddd, J(Rh,C) =
2
(vt, N = 26.4 Hz, PCHCH3), 28.2 (vt, N = 26.4 Hz, PCHCH3),
22.8 (vt, N = 3.5 Hz, PCH2CH2), 21.4 (vt, N = 4.8 Hz,
PCHCH3), 19.4, 19.3, 17.8 (all s, PCHCH3), 17.7 (vt, N =
31.4 Hz, PCH2CH2). 19F NMR (376.4 MHz, CD2Cl2):δ -78.7 (s).
31P NMR (162.0 MHz, CD2Cl2): δ 30.0 (d, 1J(Rh,P) = 165.1 Hz).
Preparation of [Rh(η4-C6H8){K2-iPr2P(CH2)3PiPr2}]CF3SO3
(41). A solution of 40 (192 mg, 0.33 mmol) in dichloromethane
(20 mL) was treated with 1,3-cyclohexadiene (200 μL, 2.10 mmol)
and stirred for 6 h at roomtemperature. The reaction mixture was
concentrated to ca. 3 mL in vacuo, and pentane (15 mL) was
added. An orange-red solid precipitated, from which the solution
was decanted. The solid residue was washed three times with pen-
tane (5 mL each) and dried in vacuo: yield 161 mg (80%); mp 87 °C
dec. Anal. Calcd for C22H42F3O3P2RhS: C, 43.43; H, 6.96; S, 5.27.
Found: C, 43.23; H, 6.66; S, 5.20. IR (CH2Cl2): ν(OSOasym) and
6.2, J(P,C) = 41.0 and 9.0 Hz, CHdCH2), 32.3, 32.1 (both
m, PCHCH3), 31.7 (dd, 1J(P,C) = 19.1, 3J(P,C) = 3.5 Hz,
PCHCH3), 28.8 (d, 1J(P,C) = 18.1 Hz, PCHCH3), 25.1 (d, 1J(P,
C) = 18.1 Hz, PCH2CH2), 22.8 (dd, 1J(P,C) = 23.2, 3J(P,C) =
1
3.5 Hz, PCH2CH2), 20.8 (d, J(P,C) = 24.8 Hz, PCH3), 21.4,
21.3, 20.1, 20.0, 19.9, 19.8, 19.2, 18.5 (all s, PCHCH3), 19.7 (s,
PCH2CH2); 43b, 87.9 (s, dCHCHd), 41.4 (dd, 1J(Rh,C) = 7.3,
2J(P,C) = 15.0 Hz, CHdCH2), 29.6 (m, PCHCH3), 29.3 (vt,
N = 21.8 Hz, PCHCH3), other signals not exactly located. 19F
NMR (376.4 MHz, CD2Cl2): δ -78.9 (s). 31P NMR (162.0 MHz,
CD2Cl2): 43a, δ 21.6 (ddd, 1J(Rh,P) = 152.0, 2J(P,P) = 18.5 and
5.4 Hz, PCHCH3), 17.9 (dt, 1J(Rh,P) = 109.0, 2J(P,P) = 18.5 Hz,
PCHCH3), -21.1 (ddd, 1J(Rh,P) = 114.2, 2J(P,P) = 18.5 and 5.4
Hz, PCH3); 43b, δ 15.9 (dt, 1J(Rh,P) = 113.3, 2J(P,P) = 8.7 Hz,
PCHCH3), -20.0 (dt, 1J(Rh,P) = 160.2, 2J(P,P) = 8.7 Hz,
PCH3).
ν(CFsym) 1270-1250 br, ν(CFasym) 1151, ν(OSOsym) 1032 cm-1
.
1H NMR (400 MHz, CD2Cl2): δ 5.37, 5.18 (br s, 2 H, CHd
CHCH2), 5.18 (br s, 2 H, CHdCHCH2), 2.45 (m, 2 H, PCHCH3),
2.05 (br m, 4 H, PCHCH3 and PCH2CH2), 1.88 (br d, 3J(H,H) =
11.7 Hz, 2 H of dCHCH2), 1.66 (m, 4 H, PCH2CH2), 1.55 (br d,
3J(H,H) = 11.7 Hz, 2 H of dCHCH2), 1.34 (dd, 3J(P,H) = 16.7,
3J(H,H) = 7.4 Hz, 6 H, PCHCH3), 1.23 (dd, 3J(P,H) = 12.7, 3J(H,
H) = 6.9 Hz, 6 H, PCHCH3), 1.08 (dd, 3J(P,H) = 15.5, 3J(H,H) =
7.0Hz,6H,PCHCH3),1.06(dd,3J(P,H) =15.6,3J(H,H) =6.7Hz,
6 H, PCHCH3). 13C NMR (100.6 MHz, CD2Cl2): δ 121.4 (q,
1J(F,C) = 321.4 Hz, CF3), 92.8 (d, 1J(Rh,C) = 5.1 Hz, CHdCH-
CH2), 81.5 (dt, 1J(Rh,C) = 6.1, 1J(P,C) = 5.1 Hz, CHdCHCH2),
30.4 (vt, N= 24.4Hz, PCHCH3), 27.7 (vt, N =24.4 Hz, PCHCH3),
23.2 (vt, N = 3.0 Hz, PCH2CH2), 21.2 (vt, N = 4.0 Hz, PCHCH3),
21.1 (s, dCHCH2), 19.3, 19.0, 17.7 (all s, PCHCH3), 18.0 (vt, N =
30.6 Hz, PCH2CH2). 19F NMR (376.4 MHz, CD2Cl2): δ -78.8 (s).
31P NMR (162.0 MHz, CD2Cl2): δ 29.5 (d, 1J(Rh,P) = 166.9 Hz).
Generation of [(η6-C6H6)Rh{K2-iPr2P(CH2)3PiPr2}]CF3SO3
(42). A solution of 41 (63 mg, 0.10 mmol) in CD2Cl2 (0.5 mL) was
heated at 50 °C in an oil bath. Following the course of the reaction
by 1H and 31P NMR spectroscopy revealed a continuous decrease
in intensity of the signals of 41 and a continuous increase in intensity
of the signals of 42. After 3 h, the signals of 41 had disappeared.
Data for 42 are as follows. 1H NMR (200 MHz, CD2Cl2): δ 7.35 (s,
Preparation of [Rh{K2-iPr2P(CH2)3PiPr2}(PMe3)2]CF3SO3
(44). This compound was prepared as described for 43 from 40
(123 mg, 0.21 mmol) and PMe3 (54 μL, 0.52 mmol). A yellow
solid was obtained: yield 133 mg (91%); mp 56 °C dec. Anal.
Calcd for C22H52F3O3P4RhS: C, 38.83; H, 7.70; S, 4.71. Found:
C, 38.51; H, 7.57; S, 4.59. IR (CH2Cl2): ν(OSOasym) and
ν(CFsym) 1270-1250 br, ν(CFasym) 1152, ν(OSOsym) 1033
1
3
cm-1. H NMR (400 MHz, CD2Cl2): δ 2.14 (dq, J(P,H) =
14.7, 3J(H,H) = 7.2 Hz, 2 H, PCH2CH2), 2.01 (m, 4 H,
PCHCH3), 1.77 (m, 4 H, PCH2CH2), 1.47 (d, J(P,H) = 5.8
2
Hz, 18 H, PCH3), 1.36-1.15 (br m, 24 H, PCHCH3), 1.26 (dd,
3J(P,H) = 12.1, 3J(H,H) = 7.2 Hz, 12 H, PCHCH3), 1.24 (dd,
3J(P,H) = 16.0, 3J(H,H) = 7.2 Hz, 12 H, PCHCH3). 13C NMR
1
(100.6 MHz, CD2Cl2): δ 121.3 (q, J(F,C) = 321.4 Hz, CF3),
28.6 (both m, PCHCH3), 21.8 (br s, PCHCH3), 21.1 (m, PCH3),
19.5 (s, PCH2CH2), 18.7 (s, PCHCH3), 17.5 (vt, N = 20.3 Hz,
PCH2CH2). 19F NMR (376.4 MHz, CD2Cl2): δ -78.7 (s). 31P
NMR (162.0 MHz, CD2Cl2): δ 30.5 (AA0 part of an AA0BB0X
spin system,, 1J(Rh,P) = -131.0, 2J(P,P) = 270.5, -43.1, and
-46.4 Hz, PCHCH3), -19.3 (BB0 part of an AA0BB0X spin
system, 1J(Rh,P) = -132.0, 2J(P,P) = 270.5, -43.1, and -46.4
Hz, PCH3).