Vinylidene transition-metal complexes, 48. - A novel route to cationic four-coordinate rhodium(I) complexes with Rh=C bonds

Article abstract of DOI:10.1002/(sici)1099-0682(199904)1999:4<613::aid-ejic613>3.0.co;2-l

The complex [Rh(acetone)₂(C₈H₁₄)₂]PF₆ (2), which is prepared from [RhCl(C₈H₁₄)₂]₂ and AgPF₆ in acetone, reacts with PiPr₃ to afford the PF₆ salt 3 of the cation [Rh(acetone)₂(PiPr₃)₂]⁺ containing the ketone and phosphane ligands in cis dispositions. Treatment of 3 with MeC≡CPh leads to the displacement of one acetone ligand and the formation of the corresponding π-alkyne complex 4. In contrast, from 3 and terminal alkynes such as HC≡CC₆H₄4-Me or HC≡CCPh₂OH the cationic vinylidenerhodium(I) compounds 5 and 6 are obtained. The latter, with C=CHCPh₂OH as the ligand, is rather labile and even at room temperature eliminates water to give the cationic four-coordinate rhodium allenylidene 7. The molecular structure of this compound has been determined by X-ray crystallography. In the presence of pyridine or ammonia, the acetone ligand of 5 and 7 is readily displaced and the substitution products 8-10 are formed almost quantitatively. Anions such as acetate or hydroxide also displace the ketone unit of 7 and yield the neutral allenylidenerhodium(I) complexes trans-[RhX(=C=C=CPh2)(PiPr₃)₂] with X = OAc (11) and OH (12).

Full text of DOI:10.1002/(sici)1099-0682(199904)1999:4<613::aid-ejic613>3.0.co;2-l

FULL PAPER
Vinylidene Transition-Metal Complexes, 48[°]
A Novel Route to Cationic Four-Coordinate Rhodium(I) Complexes with
Rh؍C Bonds
Bettina Windmüller,[a] Oliver Nürnberg,[a] Justin Wolf,[a] and Helmut Werner*[a]
Dedicated to Professor Michael F. Lappert on the occasion of his 70th birthday
Keywords: Rhodium / Ketone complexes / Vinylidene complexes / Allenylidene complexes / Ligand substitution reactions
The complex [Rh(acetone)2(C8H14)2]PF6 (2), which is
temperature eliminates water to give the cationic four-
prepared from [RhCl(C8H14)2]2 and AgPF6 in acetone, reacts coordinate rhodium allenylidene 7. The molecular structure
with PiPr3 to afford the PF6 salt
3
of the cation
of this compound has been determined by X-ray
crystallography. In the presence of pyridine or ammonia, the
acetone ligand of 5 and 7 is readily displaced and the
[Rh(acetone)2(PiPr3)2]+ containing the ketone and phosphane
ligands in cis dispositions. Treatment of 3 with MeCϵCPh
leads to the displacement of one acetone ligand and the substitution products 8–10 are formed almost quantitatively.
formation of the corresponding π-alkyne complex 4. In
contrast, from 3 and terminal alkynes such as HCϵCC6H4–
4-Me or HCϵCCPh2OH the cationic vinylidenerhodium(I)
Anions such as acetate or hydroxide also displace the ketone
unit of and yield the neutral allenylidenerhodium(I)
complexes trans-[RhX(=C=C=CPh2)(PiPr3)2] with X = OAc
7
compounds 5 and 6 are obtained. The latter, with C= (11) and OH (12).
CHCPh2OH as the ligand, is rather labile and even at room
Following the synthesis of the first square-planar structure analysis of a cationic rhodium compound with
allenylidenerhodium(I) complex trans-[RhCl(ϭCϭCϭ RhϭCϭCϭCPh2 as a molecular unit, and an alternative
CPh2)(PiPr3)2],[1] we have recently shown that rhodium al- preparative route to neutral species with XϪ instead of LЈ
lenylidenes of this particular type are useful tools for the as ligands coordinated to rhodium(I).
generation of metal bound species that are hardly accessible
by other preparative routes.[2] After having characterized a
series of compounds of the general composition trans-
Precursors of the General Composition
[RhX(ϭCϭCϭCRRЈ)(PiPr3)2] (X ϭ Cl, I, CN, OH, OPh,
cis-[Rh(acetone)2(L)2]؉
OAc, OTos),[3] we became interested to find out whether
also four-coordinate cationic allenylidenerhodium(I) com-
The procedure which we recently used for the synthesis
plexes [Rh(L)(ϭCϭCϭCRRЈ)(PiPr3)2]ϩ (L ϭ two-electron
of the above-mentioned compounds trans-[Rh(py)(L)-
donor ligand) can be obtained. Recent attempts from our
(PiPr3)2]X with L ϭ CO, C2H4 and CϭCHR[5] turned out
laboratory with the aim to prepare the cation trans-[Rh(ϭ
to be not the method of choice for L ϭ CϭCϭCPh2. Treat-
CϭCϭCPh2)2(PiPr3)2]ϩ unexpectedly led, via a novel CϪC
ment of the mixture of [Rh(η3-C3H5)(PiPr3)2] and
coupling, to the formation of two isomeric hexapentaene-
[pyH]BF4 with the propargylic alcohol HCϵCCPh2OH in
rhodium(I) compounds of which the isomer having the
acetone at room temperature led, within a short period of
polyene coordinated in an unsymmetrical fashion is the
time, to the formation of a deep red solution from which a
thermodynamically more stable.[4] However, after we found
red, moderately air-sensitive solid was obtained after re-
that carbonyl-, ethene- and even vinylidenerhodium deriva-
moval of the solvent. According to the NMR spectra it con-
tives such as trans-[Rh(py)(L)(PiPr3)2]ϩ and trans-
sisted mainly of our target, the allenylidene complex trans-
[Rh(NH3)(L)(PiPr3)2]ϩ (L ϭ CO, C2H4, CϭCHR) are ac-
[Rh(py)(ϭCϭCϭCPh2)(PiPr3)2]BF4 but also contained
Ϫ
Ϫ
cessible and, with BF4 or PF6 as counterion, stable un-
der ambient conditions,[5] we felt encouraged to prepare
also the corresponding species with L ϭ CϭCϭCRRЈ.
In this paper we report the synthesis of complexes trans-
[Rh(LЈ)(ϭCϭCϭCPh2)(PiPr3)2]PF6, the first X-ray crystal
some impurities. Despite several attempts these could not
be completely separated from the dominating species.
Therefore, we developed an alternative route to the cat-
ions [Rh(LЈ)(ϭCϭCϭCPh2)(PiPr3)2]ϩ by using the dimeric
bis(cyclooctene)rhodium(I) complex 1 as the starting mate-
rial. If a suspension of 1 in acetone is treated with a solu-
tion of AgPF6 in the same solvent at 0°C, a brownish yel-
low solution is formed from which the PF6 salt 2 can be
isolated in 74% yield. The yellow microcrystalline solid
[°]
Part 47: J. Wolf, W. Stüer, C. Grünwald, O. Gevert, M. Lauben-
der, H. Werner, Eur. J. Inorg. Chem. 1998, 1827Ϫ1834.
[a]
Institut für Anorganische Chemie der Universität Würzburg,
Am Hubland, D-97074 Würzburg, Germany
Eur. J. Inorg. Chem. 1999, 613Ϫ619
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1999
1434Ϫ1948/99/0404Ϫ0613 $ 17.50ϩ.50/0
613

B. Windmüller, O. Nürnberg, J. Wolf, H. Werner
FULL PAPER
(which decomposes at 58°C) has been characterized by el- the 13C-NMR spectrum at δ ϭ 75.0 (ϵCPh) and 64.5
emental analysis, conductivity measurements and spectro- (ϵCMe) and also the IR band at 1885 cmϪ1 assigned to
1
scopic techniques. Although the H-NMR data cannot de- ν(CϵC). The RhϪP coupling of the single 31P-NMR reso-
cide whether the structure proposed in Scheme 1 is correct, nance of 4 (116.3 Hz) is considerably smaller than that of
in analogy to the related cation [Rh(acetone)2(C8H12)]ϩ the 3 (204.9 Hz) which also supports the trans position of the
cis arrangement of the acetone ligands seems most likely.[6] two PiPr3 groups.
Scheme 1
After the isolation of the cationic compound 2 the inter-
Treatment of compound 3 with HCϵCC6H4Ϫ4-Me as a
esting question arose whether the acetone or the cyclooc- representative of a terminal acetylene derivative affords in-
tene ligands are more weakly bound to the metal center. stead of an alkyne complex the vinylidene isomer 5 almost
The experiment revealed that upon treatment of a suspen- quantitatively. If the 1-alkyne is added to a solution of 3 in
sion of 2 in ether/acetone with two equivalents of PiPr3 the diethyl ether/acetone at Ϫ78°C, a rapid change of color
olefinic groups are preferentially displaced. Upon recrystal- from violet to orange takes place indicating (see: compound
lization from acetone/diethyl ether the bis(phosphane) com- 4 is orange) that in the initial step the cation [Rh(Oϭ
plex 3 was isolated as a violet air-sensitive solid in 98% CMe2)(HCϵCR)(PiPr3)2]ϩ (R
ϭ p-tolyl) is probably
yield. The 31P-NMR spectrum of 3 displays a doublet at formed. However, even at Ϫ78°C after a few minutes the
δ ϭ 60.3 with a large RhϪP coupling that is typical for a color of the solution changes again to violet and a violet
cis-disposed [Rh(PiPr3)2] unit.[7]
solid precipitates. Upon warming to room temperature, re-
moval of the solvent and recrystallization of the residue
from acetone/diethyl ether the product was obtained in 95%
yield. In agreement with the spectroscopic data of other vi-
nylidenerhodium(I) complexes,[5][9][10] the 13C-NMR spec-
trum of 5 displays two signals (both doublets of triplets) in
the low-field region at δ ϭ 309.3 and 113.3 which are as-
signed to the α- and β-carbon atoms of the vinylidene li-
gand, respectively.
Cationic Complexes with Rh؍C Bonds
The bis(acetone)rhodium(I) complex 3 proved to be an
ideal precursor for the preparation of cationic vinylidene
and allenylidene rhodium(I) derivatives. In order to test
whether one of the metal bound ketones can be selectively
replaced by an alkyne ligand, we first carried out the reac-
tion of 3 with MeCϵCPh. It leads to the alkyne complex 4
The course of the reaction of the bis(acetone)rhodium(I)
(Scheme 2) as an orange air-sensitive solid in 75% yield. compound 3 with the propargylic alcohol HCϵCCPh2OH
1
In contrast to 3, the H-NMR spectrum of 4 displays two in diethyl ether/acetone is at least in the initial stage quite
resonances for the CH3 protons of the isopropyl moieties, similar to that of 3 with HCϵCC6H4Ϫ4-Me (see Scheme
the virtual coupling of both points to a trans arrangement 3). If the solution, after it was stirred at Ϫ78°C for 2 min
of the phosphane ligands.[8] Typical features of the π- and then warmed to 0°C, was quickly worked up an or-
bonded unsymmetrical alkyne unit are the two signals in ange-red solid was isolated which based on the NMR spec-
Scheme 2
614
Eur. J. Inorg. Chem. 1999, 613Ϫ619

Vinylidene Transition-Metal Complexes, 48
FULL PAPER
tra consists of a mixture of the functionalized vinylidene [P1, P2, Rh, O1, C1] and we assume that this minimizes the
compound 6 and the allenylidene complex 7, the first being steric repulsion between the OϭCMe2 and the PiPr3 li-
the dominating species. Attempts to obtain 6 as an analyti- gands.
cally pure solid failed since the crude product upon disso-
lution, e.g., in acetone or dichloromethane smoothly con-
verted completely to 7. In acetone at room temperature, the
formation of 7 is completed in ca. 15 min. Removal of the
solvent and recrystallization of the residue from acetone/
Ligand Substitution Reactions of Compounds
5 and 7
diethyl ether gave orange crystals which were characterized
The observation that in the starting material 3 one of
by elemental analysis, conductivity measurements and spec- the ketone ligands could be easily replaced by an alkyne,
troscopic means. In contrast to the neutral compounds vinylidene or allenylidene unit, led us to try to substitute
trans-[RhCl{ϭCϭCϭC(Ph)R}(PiPr3)2],[1][11] in the 13C- also the remaining acetone moiety in the cations trans-
NMR spectrum of 7 the resonances of the α-and β-carbon [Rh(OϭCMe2)(L)(PiPr3)2]ϩ by an olefin, alkyne or even a
atoms of the RhϭCϭCϭC moiety could not be observed, more typical π-acceptor ligand such as CO. However, all
even if a saturated solution of 7 in [D6]acetone was used. these attempts failed. Nevertheless, the displacement of ace-
The signal of the respective γ-carbon atom appears at δ ϭ tone in the vinylidene and allenylidene complexes 5 and 7
150.8 as a singlet.
can be achieved with N-donors such as pyridine or am-
Scheme 3
In order to confirm the structure proposed for 7 [which monia under very mild conditions. After workup the substi-
is the first cationic allenylidenerhodium(I) complex], an X- tution products 8Ϫ10 were isolated in 85Ϫ90% yield
ray crystal structure analysis was carried out. The result is (Scheme 4). The properties of the pyridine- and ammonia-
shown in Figure 1. The coordination geometry around the containing cationic compounds are very similar to those of
rhodium center is almost exactly square-planar with bond the acetone derivatives 5 and 7 and thus deserve no further
angles P1ϪRhϪP2 and O1ϪRhϪC1 of 176.78(2)° and comment. It should be mentioned, however, that since for
˚
178.67(9)°. The RhϪC1 distance is 1.822(2) A and thus the preparation of 10 aqueous ammonia was used as the
somewhat shorter than in trans-[RhCl{ϭCϭCϭ substrate, the CϭCϭCPh2 ligand is not attacked by OHϪ
[11]
˚
C(Ph)C6H4Ϫ2-Me}(PiPr3)2] [1.855(5) A].
The shorten- or H2O as a nucleophile as was observed with a variety of
ing is surprising insofar as in cationic rhodium(I) species cationic six-coordinate allenylidenemetal complexes.[12] The
the degree of π-back bonding should be smaller compared 13C-NMR spectrum of 9 displays the three expected signals
to structurally related neutral derivatives. The bond length for the α-, β- and γ-carbon atoms of the RhϪCϪCϪC
C1ϪC2 [1.267(3) A] is slightly longer and the bond length chain at δ ϭ 270.4, 229.6 and 150.9, of which those at
C1ϪC3 [1.343(3) A] slightly shorter than in the above- lowest fields (assigned to α-C and β-C) are split into
˚
˚
mentioned
allenylidene(chloro)rhodium(I)
compound doublets of triplets.
˚
˚
[C1ϪC2 ϭ 1.239(8) A, C2ϪC3 ϭ 1.370(9) A], indicating
In order to illustrate that the acetone ligand of com-
that for the bonding situation the resonance structure B pound 7 can also be displaced by coordinating anions, the
(Figure 2) is less important in the cationic complex than in known acetato- and hydroxorhodium(I) derivatives 11 and
the neutral analog. The RhϪCϪCϪC chain is nearly linear, 12 were prepared by this route (Scheme 5). From 7 as the
with only a slight bending at the carbon atom C2. The starting material and with CH3CO2Na or KOH as the sub-
planes of the two phenyl groups are not perpendicular to strate, the isolated yield of 11 and 12 is ca. 80%. The neutral
each other like the aryl rings in trans-[RhCl{ϭCϭCϭ allenylidene complex 12 with OH in trans position to the
C(Ph)C6H4Ϫ2-Me}(PiPr3)2] but form a dihedral angle of C3Ph2 unit was originally prepared from the chloro com-
68.31(8)°. The atoms O1, C34, C35 and C36 of the acetone pound trans-[RhCl(ϭCϭCϭCPh2)(PiPr3)2] and KOtBu in
ligand lie in a plane which is orthogonal to the central plane C6H6/tBuOH and upon treatment with acetic acid trans-
Eur. J. Inorg. Chem. 1999, 613Ϫ619
615

B. Windmüller, O. Nürnberg, J. Wolf, H. Werner
FULL PAPER
Figure 1. Molecular structure (ORTEP plot) of the cation of compound 7; the hydrogen atoms are omitted for clarity; selected bond
˚
lengths (A) and angles [°]: RhϪP1 2.3557(6), RhϪP2 2.3513(6), RhϪO1 2.078(2), RhϪC1 1.822(2), C1ϪC2 1.267(3), C2ϪC3 1.343(3),
C3ϪC4 1.472(3), C3ϪC5 1.491(3), O1ϪC34 1.216(3); P1ϪRhϪP2 176.78(2), P1ϪRhϪO1 90.08(5), P1ϪRhϪC1 90.11(6), P2ϪRhϪO1
92.41(5), P2ϪRhϪC1 87.45(6), O1ϪRhϪC1 178.67(9), RhϪC1ϪC2 178.1(2), C1ϪC2ϪC3 172.6(2), C2ϪC3ϪC4 122.8(2), C2ϪC3ϪC5
118.2(2), O1ϪC34ϪC35 119.1(3), O1ϪC34ϪC36 122.4(3)
um(I) complexes of the general composition trans-[RhX(ϭ
CϭCϭCPh2)(PiPr3)2].
Figure 2. Resonance structures for allenylidenemetal complexes
Concluding Remarks
formed to the acetato derivative.[2b][3] Some exploratory
The present investigation has shown that in addition to
studies indicate that it is possible to substitute the acetone the well-known neutral rhodium allenylidenes trans-
Ϫ
ligand of 7 also by C-nucleophiles such as CH(CN)2 or [RhX(ϭCϭCϭCRRЈ)(PiPr3)2] structurally related cationic
CNϪ and thus the reaction of 7 with XϪ could be an complexes trans-[Rh(ϭCϭCϭCPh2)(L)(PiPr3)2]ϩ with L ϭ
alternative route for the preparation of allenylidenerhodi- acetone, pyridine or ammonia are also accessible. The
Scheme 4
616
Eur. J. Inorg. Chem. 1999, 613Ϫ619

Vinylidene Transition-Metal Complexes, 48
FULL PAPER
Scheme 5
m, 24 H, CH2 of C8H14). Ϫ C22H40F6O2PRh (584.4): calcd. C
45.21, H 6.90; found C 44.98, H 6.61.
method of choice for preparing these compounds (as the
PF6 salts) is the “alkynol route”, which was developed by
Selegue[13] and later used by us[3][14] and several other
groups as well.[15][16] The most remarkable feature is that
the starting material 3 (which despite the lability of the ace-
tone-metal bonds has been isolated and fully characterized)
reacts with terminal alkynes HCϵCR, including the pro-
pargylic alcohol HCϵCCPh2OH, almost instantaneously
to give cationic vinylidene compounds with RhϭCϭCHR
as the central unit. Since all attempts to detect the corre-
sponding alkynerhodium(I) derivatives assumed to be
formed in the initial step failed, we conclude that the metal-
assisted isomerization of HCϵCR to CϭCHR takes place
considerably faster in the coordination sphere of a four-
coordinate cationic than of a related neutral d8 metal center.
With regard to the subsequent conversion of the RhϭCϭ
CHCPh2OH to the RhϭCϭCϭCPh2 unit we note that in
the case of the cationic species the elimination of water also
occurs much more readily than for the analogous neutral
derivative and that neither the presence of Al2O3 nor of
Brønsted acids HX is necessary for this process.
2. Preparation of cis-[Rh(O؍CMe2)2(PiPr3)2]PF6 (3): A suspension
of 90 mg (0.15 mmol) of 2 in 10 mL of diethyl ether/acetone (9:1)
was treated at Ϫ78°C with 62 µL (0.31 mmol) of PiPr3. Under
continuous stirring the reaction mixture was slowly warmed to
room temp. (ca. 30 min) which led to a change of color from yellow
to dark violet. Moreover, a small amount of a violet solid precipi-
tated. The solution was concentrated to ca. 1 mL in vacuo and then
10 mL of diethyl ether was added. After the mixture was stored for
2 h, the violet precipitate was separated from the mother liquor,
washed three times with 2-mL portions of diethyl ether and dried;
yield 103 mg (98%); dec. temp. 83°C; Λ ϭ 110 cm2ΩϪ1molϪ1. Ϫ
IR (CH2Cl2): ν˜ ϭ 1705, 1653 cmϪ1 (CϭO). Ϫ 1H NMR (200 MHz,
(CD3)2CO): δ ϭ 2.08 (s, 12 H, OϭCMe2), 2.03 (m, 6 H, PCHCH3),
1.40 [dd, J(PH) ϭ 13.1, J(HH) ϭ 7.3 Hz, 36 H, PCHCH3]. Ϫ 31P
NMR (81.0 MHz, (CD3)2CO): δ ϭ 60.3 [d, J(RhP) ϭ 204.9 Hz].
Ϫ C24H54F6O2P3Rh (684.5): calcd. C 42.11, H 7.95; found C 42.62,
H 7.84.
3. Preparation of trans-[Rh(O؍CMe2)(MeCϵCPh)(PiPr3)2]PF6 (4):
A suspension of 103 mg (0.15 mmol) of 3 in 10 mL of diethyl ether/
acetone (9:1) was treated at Ϫ78°C with 19 µL (0.15 mmol) of
MeCϵCPh. After the reaction mixture was slowly warmed to room
temp. (ca. 30 min), it was worked up analogously as described for
3. Orange microcrystalline solid; yield 84 mg (75%); dec. temp.
44°C; Λ ϭ 77 cm2ΩϪ1molϪ1. Ϫ IR (CH2Cl2): ν˜ ϭ 1885 (CϵC),
Experimental Section
1
1707 cmϪ1 (CϭO). Ϫ H NMR (400 MHz, (CD3)2CO): δ ϭ 7.68
General: All operations were carried out under argon using Schlenk
techniques. The starting material [RhCl(C8H14)2]2 (1)[17] and the
propargylic alcohol HCϵCCPh2OH[18] were prepared as described
in the literature. The other alkynes were commercial products from
ABCR and Aldrich. Ϫ IR: Perkin-Elmer 1420. Ϫ NMR: Bruker
AC 200 and AMX 400 [dvt ϭ doublet of virtual triplets; N ϭ
3J(PH) ϩ 5J(PH) or 2J(PC) ϩ 4J(PC), respectively]. Ϫ Conductivity
measurements in nitromethane with a Schott Konduktometer CG
851. Ϫ Melting and decomposition points determined by DTA.
(m, 5 H, C6H5), 2.50 (br. s, 3 H, ϵCMe), 2.08 (s, 6 H, OϭCMe2),
1.94 (m, 6 H, PCHCH3), 1.37 [dvt, N ϭ 13.5, J(HH) ϭ 7.0 Hz, 18
H, PCHCH3], 1.12 [dvt, N ϭ 13.1, J(HH) ϭ 6.8 Hz, 18 H,
PCHCH3]. Ϫ 13C NMR (100.6 MHz, (CD3)2CO): δ ϭ 206.2 (s,
OϭCMe2), 130.9, 129.1, 128.8, 127.7 (all s, C6H5), 75.0 (br. m,
ϵCPh), 64.5 (br. m, ϵCMe), 30.4 (s, OϭCCH3), 23.5 (vt, N ϭ 17.7
Hz, PCHCH3), 20.8, 19.6 (both s, PCHCH3), 13.2 (s, ϵCCH3). Ϫ
31P NMR (81.0 MHz, (CD3)2CO): δ ϭ 33.9 [d, J(RhP) ϭ 116.3
Hz]. Ϫ C30H56F6OP3Rh (742.6): calcd. C 48.52, H 7.60; found C
48.42, H 7.33.
1. Preparation of cis-[Rh(O؍CMe2)2(C8H14)2]PF6 (2): A suspen-
sion of 404 mg (0.56 mmol) of 1 in 30 mL of acetone was treated
dropwise at 0°C with a solution of 276 mg (1.09 mmol) of AgPF6 4. Preparation of trans-[Rh(O؍CMe2)(؍C؍CHC6H4؊4-Me)(Pi-
in 2 mL of acetone. Under continuous stirring the reaction mixture
was slowly warmed to room temp. (ca. 20 min) and after it was
Pr3)2]PF6 (5): A suspension of 103 mg (0.15 mmol) of 3 in 10 mL
of diethyl ether/acetone (9:1) was treated at Ϫ78°C with 19 µL
stored for 1 h the solution was filtered. The filtrate was concen- (0.15 mmol) of HCϵCC6H4Ϫ4-Me. A rapid change of color from
trated to ca. 5 mL in vacuo and 20 mL of diethyl ether was added.
A yellow microcrystalline solid precipitated which was separated
from the mother liquor, washed three times with 2-mL portions of
violet to orange occurred which after ca. 5 min was followed by a
reverse change of color from orange to violet. Upon continuous
stirring a violet solid precipitated. The reaction mixture was slowly
warmed to room temp. (ca. 30 min), and after it was stirred for 8
diethyl ether and dried; yield 471 mg (74%); dec. temp. 58°C; Λ ϭ
1
80 cm2ΩϪ1molϪ1. Ϫ H NMR (200 MHz, CD3NO2): δ ϭ 2.97 (m, h the solvent was removed in vacuo. The residue was dissolved in
4 H, ϭCH of C8H14), 2.42 (s, 12 H, OϭCMe2), 2.25, 1.62, 1.42 (all 1 mL of acetone and 20 mL of diethyl ether was added to the
Eur. J. Inorg. Chem. 1999, 613Ϫ619
617

B. Windmüller, O. Nürnberg, J. Wolf, H. Werner
FULL PAPER
solution. Violet crystals were formed which were washed three
rated from the mother liquor, washed three times with 2-mL por-
tions of diethyl ether and dried; yield 86 mg (91%); dec. temp.
times with 2-mL portions of diethyl ether and dried; yield 106 mg
1
(95%); dec. temp. 98°C; Λ ϭ 92 cm2ΩϪ1molϪ1. Ϫ H NMR [400 96°C. Ϫ 1H NMR (200 MHz, CD3NO2): δ ϭ 8.03 (m, 5 H,
MHz, (CD3)2CO]: δ ϭ 6.65 (m, 4 H, C6H4), 2.46 (m, 6 H,
NC5H5), 6.63 (m, 4 H, C6H4), 2.42 (m, 6 H, PCHCH3), 2.28 (s, 3
PCHCH3), 2.30 (s, 3 H, C6H4CH3), 2.08 (s, 6 H, OϭCMe2), 1.38 H, C6H4CH3), 1.39 [dvt, N ϭ 14.0, J(HH) ϭ 7.0 Hz, 36 H,
[dvt, N ϭ 14.0, J(HH) ϭ 7.0 Hz, 36 H, PCHCH3]; signal of ϭCH PCHCH3]; signal of ϭCH proton probably covered by signal of
proton probably covered by signal of PCHCH3 protons. Ϫ 13C
PCHCH3 protons. Ϫ 13C NMR (50.3 MHz, CD3NO2): δ ϭ 309.2
NMR [100.6 MHz, (CD3)2CO]: δ ϭ 309.3 [dt, J(RhC) ϭ 61.4, [dt, J(RhC) ϭ 61.2, J(PC) ϭ 17.4 Hz, RhϭC], 151.8, 140.5, 136.2,
J(PC) ϭ 17.6 Hz, RhϭC], 206.3 (s, OϭCMe2), 136.2, 129.8, 126.8, 129.7, 127.3, 126.8, 121.5 (all s, NC5H5 and C6H4), 114.3 [dt,
120.6 (all s, C6H4), 113.3 [dt, J(RhC) ϭ 16.1, J(PC) ϭ 6.0 Hz, J(RhC) ϭ 16.0, J(PC) ϭ 6.1 Hz, ϭCH], 24.6 (vt, N ϭ 20.9 Hz,
ϭCH], 30.3 (s, OϭCCH3), 24.3 (vt, N ϭ 20.9 Hz, PCHCH3), 20.8
PCHCH3), 21.1 (s, C6H4CH3), 20.1 (s, PCHCH3). Ϫ 31P NMR
(s, C6H4CH3), 20.1 (s, PCHCH3). Ϫ 31P NMR (162.0 MHz, [162.0 MHz, (CD3)2CO]: δ ϭ 40.3 [d, J(RhP) ϭ 134.9 Hz].
(CD3)2CO): δ ϭ 42.5 [d, J(RhP) ϭ 135.1 Hz]. Ϫ C30H56F6OP3Rh C32H55F6NP3Rh (763.6): calcd. C 50.33, H 7.62, N 1.83; found C
(742.6): calcd. C 48.52, H 7.60; found C 48.56, H 7.62.
49.56, H 7.62, N 1.50.
8. Preparation of trans-[Rh(؍C؍C؍CPh2)(py)(PiPr3)2]PF6 (9):
Analogously as described for 8, by using 123 mg (0.15 mmol) of 7
and ca. 0.5 mL of pyridine as starting materials. Red-violet solid;
yield 109 mg (87%); dec. temp. 98°C. Ϫ IR (CH2Cl2): ν˜ ϭ 1916
cmϪ1 (CϭCϭC). Ϫ 1H NMR (400 MHz, CD3NO2): δ ϭ 8.38, 7.48,
7.27 (all m, 5 H, NC5H5), 7.92, 7.59, 7.37 (all m, 10 H, C6H5), 2.16
(m, 6 H, PCHCH3), 1.24 [dvt, N ϭ 13.7, J(HH) ϭ 6.6 Hz, 36 H,
PCHCH3]. Ϫ 13C NMR (100.6 MHz, CD3NO2): δ ϭ 270.4 [dt,
J(RhC) ϭ 56.0, J(PC) ϭ 19.0 Hz, RhϭC], 229.6 [dt, J(RhC) ϭ
15.0, J(PC) ϭ 9.0 Hz, RhϭCϭC], 153.2, 140.3, 131.1, 129.7, 128.1,
127.3, 126.5 (all s, NC5H5 and C6H5), 150.9 (s, ϭCPh2), 26.4 (vt,
N ϭ 20.0 Hz, PCHCH3), 20.5 (s, PCHCH3). Ϫ 31P NMR (162.0
5. Generation of trans-[Rh(O؍CMe2)(؍C؍CHCPh2OH)-
(PiPr3)2]PF6 (6): A suspension of 103 mg (0.15 mmol) of 3 in 10
mL of diethyl ether/acetone (9:1) was treated at Ϫ78°C with 31 mg
(0.15 mmol) of HCϵCCPh2OH. A rapid change of color from vi-
olet to orange occurred. After the solution was stirred for 2 min
and then warmed to 0°C, it was concentrated to ca. 1 mL in vacuo.
Upon dropwise addition of diethyl ether and subsequently of pen-
tane (ca. 10 mL) an orange-red solid precipitated which was sepa-
rated from the mother liquor, washed three times with 2-mL por-
tions of diethyl ether, then with 2 mL of pentane, and dried. The
1H- and 31P-NMR spectra revealed that besides 6 also compound
7 was formed. Ϫ IR (CH2Cl2): ν˜ ϭ 3410 (OH), 1642 cmϪ1 (CϭC).
MHz, CD3NO2):
δ ϭ 38.2 [d, J(RhP) ϭ 134.0 Hz]. Ϫ
Ϫ
1H NMR [400 MHz, (CD3)2CO]: δ ϭ 7.57 (m, 10 H, C6H5),
C38H57F6NP3Rh (837.7): calcd. C 54.99, H 6.86, N 1.67; found C
54.87, H 7.20, N 1.79.
3.05 (br. s, 1 H, OH), 2.41 (m, 6 H, PCHCH3), 2.08 (s, 6 H, Oϭ
CMe2), 1.30 [dvt, N ϭ 13.9, J(HH) ϭ 6.8 Hz, 36 H, PCHCH3];
signal of ϭCH proton probably covered by signal of PCHCH3 pro-
tons. Ϫ 13C NMR [100.6 MHz, (CD3)2CO]: δ ϭ 206.3 (s, Oϭ
CMe2), 130.2, 128.4, 125.9 (all s, C6H5), 117.8 [dt, J(RhC) ϭ 17.1,
J(PC) ϭ 6.0 Hz, ϭCH], 72.0 (s, CPh2OH), 30.2 (s, OϭCCH3), 23.9
(vt, N ϭ 20.7 Hz, PCHCH3), 19.8 (s, PCHCH3); signal of RhϭC
not exactly located. Ϫ 31P NMR [162.0 MHz, (CD3)2CO]: δ ϭ 42.3
[d, J(RhP) ϭ 135.9 Hz].
9. Preparation of trans-[Rh(؍C؍C؍CPh2)(NH3)(PiPr3)2]PF6 (10):
A solution of 123 mg (0.15 mmol) of 7 in 10 mL of CH2Cl2 was
treated at Ϫ20°C with 2.8 mL of a 0.55  solution of NH4OH
(0.15 mmol) in water. The solution was slowly warmed to room
temp. and, after it was continuously stirred for 1 h, concentrated
to ca. 1 mL in vacuo. The solution was then layered with 10 mL
of diethyl ether and upon storing for 6 h at room temp. red crystals
were formed. The crystals were separated from the mother liquor,
washed three times with 2-mL portions of diethyl ether and pen-
tane and dried; yield 116 mg (85%); dec. temp. 134°C. Ϫ IR
(CH2Cl2): ν˜ ϭ 1905 cmϪ1 (CϭCϭC). Ϫ 1H NMR (400 MHz,
CD3NO2): δ ϭ 7.89, 7.31 (both m, 10 H, C6H5), 2.52 (m, 6 H,
PCHCH3), 1.32 [dvt, N ϭ 13.4, J(HH) ϭ 6.7 Hz, 36 H, PCHCH3].
6. Preparation of trans-[Rh(O؍CMe2)(؍C؍C؍CPh2)(PiPr3)2]PF6
(7): A suspension of 103 mg (0.15 mmol) of 3 in 10 mL of diethyl
ether/acetone (9:1) was treated at Ϫ78°C with 31 mg (0.15 mmol)
of HCϵCCPh2OH, and upon warming to room temp. was stirred
for 15 h. The solvent was removed, the residue was dissolved in 1
mL of acetone and the solution was layered with 20 mL of diethyl
ether. Orange crystals were formed which were separated from the
mother liquor, washed three times with 2-mL portions of diethyl
ether, once with 2 mL of pentane, and dried; yield 93 mg (76%);
dec. temp. 62°C; Λ ϭ 87 cm2ΩϪ1molϪ1. Ϫ IR (KBr): ν˜ ϭ 1873
cmϪ1 (CϭCϭC). Ϫ 1H NMR [400 MHz, (CD3)2CO]: δ ϭ 7.73 (m,
10 H, C6H5), 2.49 (m, 6 H, PCHCH3), 2.18 (s, 6 H, OϭCMe2),
1.41 [dvt, N ϭ 13.8, J(HH) ϭ 7.1 Hz, 36 H, PCHCH3]. Ϫ 13C
NMR [100.6 MHz, (CD3)2CO]: δ ϭ 206.3 (s, OϭCMe2), 150.8 (s,
RhϭCϭCϭC), 130.5, 130.3, 126.5 (all s, C6H5), 30.2 (s, OϭCCH3),
24.8 (vt, N ϭ 20.6, PCHCH3), 20.0 (s, PCHCH3); signals of α- and
β-carbon atoms of RhϭCϭCϭC unit not exactly located. Ϫ 31P
NMR [162.0 MHz, (CD3)2CO]: δ ϭ 41.8 [d, J(RhP) ϭ 132.7 Hz].
Ϫ C36H58F6OP3Rh (816.7): calcd. C 52.94, H 7.16, Rh 12.60; found
C 52.51, H 6.87, Rh 13.00.
Ϫ
13C NMR (100.6 MHz, CD3NO2): δ ϭ 269.1 (br. m, RhϭC),
230.5 [dt, J(RhC) ϭ 19.0 J(PC) ϭ 7.0 Hz, RhϭCϭC], 151.8 (s,
ϭCPh2), 152.4, 130.7, 130.1, 127.0 (all s, C6H5), 25.5 (vt, N ϭ 20.0
Hz, PCHCH3), 20.4 (s, PCHCH3). Ϫ 31P NMR (162.0 MHz,
CD3NO2): δ ϭ 41.6 [J(RhP) ϭ 131.0 Hz]. Ϫ C33H55F6NP3Rh
(775.6): calcd. C 51.10, H 7.15, N 1.81; found C 50.87, H 7.12,
N 1.78.
10. Preparation of trans-[Rh(OAc)(؍C؍C؍CPh2)(PiPr3)2] (11): A
suspension of 123 mg (0.15 mmol) of 7 in 10 mL of diethyl ether/
acetone (9:1) was treated at Ϫ78°C with 12 mg (0.15 mmol) of
sodium acetate. A rapid change of color from deep orange to green
occurred. Under continuous stirring the reaction mixture was
warmed to room temp. and then brought to dryness in vacuo. The
residue was extracted with 20 mL of diethyl ether, and the solvent
was removed from the extract. The residue was dissolved in 2 mL
of acetone and the solution was stored at Ϫ20°C for 8 h. Green
7. Preparation of trans-[Rh(؍C؍CHC6H4؊4-Me)(py)(PiPr3)2]PF6
(8): A suspension of 111 mg (0.15 mmol) of 5 in 10 mL of diethyl crystals were formed which were separated from the mother liqour,
ether was treated at Ϫ78°C with an excess (ca. 0.5 mL) of pyridine
which led to the precipitation of a red-violet solid. After the reac-
tion mixture was warmed under continuous stirring to room temp.
(ca. 30 min), it was stored for 1 h. The red-violet solid was sepa-
washed three times with 2-mL portions of acetone (Ϫ20°C) and
dried; yield 82 mg (81%). Compound 11 was identified by compari-
son of the IR and NMR data with those of an authentic
sample.[2b][19]
618
Eur. J. Inorg. Chem. 1999, 613Ϫ619

Vinylidene Transition-Metal Complexes, 48
FULL PAPER
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R. R. Schrock, J. A. Osborn, J. Am. Chem. Soc. 1971, 93,
3089Ϫ3091.
11. Preparation of trans-[Rh(OH)(؍C؍C؍CPh2)(PiPr3)2] (12):
Analogously as described for 11, by using 123 mg (0.15 mmol) of
7 and 8 mg (0.15 mmol) of KOH as starting materials. Green solid;
yield 76 mg (79%). Compound 12 was identified by comparison of
the IR and NMR data with those of an authentic sample.[2b][19]
[7] [7a]
M. Schäfer, J. Wolf, H. Werner, J. Chem. Soc., Chem. Com-
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[7c]
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12. Determination of the X-ray Crystal Structure of 7:[20] Single
crystals were grown from acetone/diethyl ether at room temp. Crys-
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[8]
R. K. Harris, Can. J. Chem. 1962, 42, 2275Ϫ2281.
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H. Werner, F. J. Garcia Alonso, H. Otto, J. Wolf, Z. Natur-
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H. Werner, U. Brekau, Z.
˚
[9c]
P-1 (No. 2); a ϭ 9.074(6), b ϭ 14.42(1), c ϭ 16.16(1) A, α ϭ
Naturforsch., B 1989, 44, 1438Ϫ1446. Ϫ
H. Werner, T. Rap-
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3
˚
85.50(5), β ϭ 87.16(5), γ ϭ 77.61(5)°; V ϭ 2057(3) A , Z ϭ 2;
dcalcd. ϭ 1.32 gcmϪ3; µ(Mo-Kα) ϭ 5.7 cmϪ1; crystal size 0.15 ϫ
0.15 ϫ 0.40 mm; Enraf-Nonius CAD-4 diffractometer, Mo-Kα
O. Nürnberg, N. Mahr, J. Wolf, H. Werner, Organometallics
[9e]
1992, 11, 4156Ϫ4164. Ϫ
T. Rappert, O. Nürnberg, H.
Werner, Organometallics 1993, 12, 1359Ϫ1364. Ϫ [9f] H. Werner,
˚
radiation (λ ϭ 0.71073 A), graphite monochromator, zirconium fil-
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13, 1089Ϫ1097. Ϫ
M. Baum, B. Windmüller, H. Werner, Z.
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reflections measured, 6442 independent (Rint. ϭ 0.0091), 5779 with
Fo > 2σ(Fo). Intensity data were corrected for Lorentz and polari-
zation effects and an empirical absorption correction (Ψ-scan
method) was applied (min. transmission 96.1%). The structure was
solved by direct methods (SHELXS-86).[21] Atomic coordinates
and the anisotropic thermal parameters of non-hydrogen atoms
were refined by full-matrix least squares on F2 (SHELXS-93).[22]
[9h]
Naturforsch., B 1994, 49, 859Ϫ869. Ϫ
M. Schäfer, J. Wolf,
[9i]
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H.
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[10]
[11]
C. Bianchini, F. Laschi, F. Ottaviani, M. Peruzzini, P. Zanello,
Organometallics 1988, 7, 1660Ϫ1661.
H. Werner, T. Rappert, R. Wiedemann, J. Wolf, N. Mahr, Or-
ganometallics 1994, 13, 2721Ϫ2727.
[12] [12a]
M. A. Esteruelas, A. V. Gomez, F. J. Lahoz, A. M. Lopez,
Ϫ
E. On˜ate, L. A. Oro, Organometallics 1996, 15, 3423Ϫ3435. Ϫ
[12b] N. Ruiz, D. Peron, S. Sinbandith, P. H. Dixneuf, C. Baldoli,
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J. P. Selegue, Organometallics 1982, 1, 217Ϫ218.
The PF6 anion is disordered. The positions of 18 fluorine atoms
(3 ϫ 6) could be located around the central phosphorus atom P3
and refined anisotropically with a weighting factor of 1/3. The posi-
tions of all hydrogen atoms could be located in a final difference
Fourier synthesis and refined isotropically. Conventional R ϭ
0.0216 [for 5779 reflections with Fo > 2σ(Fo)], and weighted wR2 ϭ
0.0612 for all 6442 located reflections; reflection/parameter ratio
[13]
[14] [14a]
P. Schwab, H. Werner, J. Chem. Soc, Dalton Trans. 1994,
[14b]
3415Ϫ3425. Ϫ
T. Braun, P. Steinert, H. Werner, J. Or-
[14c]
ganomet. Chem. 1995, 488, 169Ϫ176. Ϫ
H. Werner, A.
Stark, P. Steinert, C. Grünwald, J. Wolf, Chem. Ber. 1995, 128,
49Ϫ62. Ϫ [14d] B. Windmüller, J. Wolf, H. Werner, J. Organomet.
Ϫ3
˚
[14e]
10.1; residual electron density ϩ0.20/-0.27 eA
.
Chem. 1995, 502, 147Ϫ161. Ϫ
M. Martin, O. Gevert, H.
[14f]
Werner, J. Chem. Soc., Dalton Trans. 1996, 2275Ϫ2283. Ϫ
H. Werner, R. Lass, O. Gevert, J. Wolf, Organometallics 1997,
[14g]
16, 4077Ϫ4088. Ϫ
C. Grünwald, M. Laubender, J. Wolf,
H. Werner, J. Chem. Soc., Dalton Trans. 1998, 833Ϫ839. Ϫ [14h]
H. Werner, C. Grünwald, P. Steinert, O. Gevert, J. Wolf, J. Or-
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[15a]
Inter alia:
H. Fischer, D. Reindl, G. Roth, Z. Naturforsch.,
This work was supported by the Deutsche Forschungsgemein-
schaft (SFB 347) and the Fonds der Chemischen Industrie (Pro-
motionsstipendium to O. N.). We are grateful to Mrs. R. Schedl
and Mr. C. P. Kneis for performing the elemental analyses and
DTA measurements, to Dr. B. Stempfle and Dr. W. Buchner for
NMR spectra, and in particular to Mrs. A. Spenkuch for valuable
technical assistance. Degussa AG generously supported this work
by gifts of chemicals.
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Crystallographic data (excluding structure factors) for the struc-
tures reported in this paper have been deposited with the Cam-
bridge Crystallographic Data Centre as supplementary publi-
cation no. CCDC-106914 Copies of the data can be obtained
free of charge on application to CCDC, 12 Union Road, Cam-
bridge CB2 1EZ, UK (Fax: internat. ϩ 44Ϫ1223/336Ϫ033;
E-mail: deposit@ccdc.cam.ac.uk).
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[5]
Received November 3, 1998
[I98378]
Eur. J. Inorg. Chem. 1999, 613Ϫ619
619