Dinuclear rhodium complexes containing a linear C2RhC4RhC2 chain

Article abstract of DOI:10.1021/om9710780

The reaction of trans-[RhCl(=C=CHPh)(PiPr₃)₂] (1) and trans-[RhCl(=C=CMe₂)(PiPr₃)₂] (3) with 50% aqueous NaOH, in the presence of TEBA, afforded the hydroxorhodium complexes trans-[Rh(OH)(=C=CRR′)(PiPr₃)₂] (2, 4) in good to excellent yield. Compound 2 (R = H, R′ = Ph) reacted with D₂O to give trans-[Rh(OD)(=C=CHPh)(PiPr₃)₂] (2-d) and with Br?nsted acids HX (X = CF₃CO₂, OPh, C≡CPh) to yield the corresponding derivatives trans-[Rh(X)(=C=CHPh)(PiPr₃)₂] (5-7), respectively. Treatment of 2 and 4 with Ph₃-SnC≡CC≡CSnPh₃ also led to the displacement of the hydroxo ligand and to the formation of the dinuclear complexes tran,trans-[{Rh(=C=CRR′)(PiPr₃)₂} ₂(μ-C₄)] (8, 9) in 75-80% yield. The X-ray crystal structure analysis of 9 revealed the presence of a linear 10-atom C=C=RhC≡CC≡CRh=C=C chain with the midpoint of the central C-C bond as a crystallographic center of symmetry.

Full text of DOI:10.1021/om9710780

1202
Organometallics 1998, 17, 1202-1207
Din u clea r Rh od iu m Com p lexes Con ta in in g a Lin ea r
C2Rh C4Rh C2 Ch a in 1
J uan Gil-Rubio, Matthias Laubender, and Helmut Werner*
Institut fu¨r Anorganische Chemie der Universita¨t Wu¨rzburg,
Am Hubland, D-97074 Wu¨rzburg, Germany
Received December 9, 1997
The reaction of trans-[RhCl(dCdCHPh)(PiPr3)2] (1) and trans-[RhCl(dCdCMe2)(PiPr3)2]
(3) with 50% aqueous NaOH, in the presence of TEBA, afforded the hydroxorhodium
complexes trans-[Rh(OH)(dCdCRR′)(PiPr3)2] (2, 4) in good to excellent yield. Compound 2
(R ) H, R′ ) Ph) reacted with D2O to give trans-[Rh(OD)(dCdCHPh)(PiPr3)2] (2-d ) and
with Brønsted acids HX (X ) CF3CO2, OPh, CtCPh) to yield the corresponding derivatives
trans-[Rh(X)(dCdCHPh)(PiPr3)2] (5-7), respectively. Treatment of 2 and 4 with Ph3-
SnCtCCtCSnPh3 also led to the displacement of the hydroxo ligand and to the formation
of the dinuclear complexes trans,trans-[{Rh(dCdCRR′)(PiPr3)2}2(µ-C4)] (8, 9) in 75-80% yield.
The X-ray crystal structure analysis of 9 revealed the presence of a linear 10-atom
CdCdRhCtCCtCRhdCdC chain with the midpoint of the central C-C bond as a
crystallographic center of symmetry.
In tr od u ction
vinylidene units are disposed trans to a naked C4 (or
Cn) bridge.
In the search for highly reactive metallacumulenes
of the general composition trans-[Rh(X)(dCdCdCRPh)-
(PiPr3)2], we recently reported that the hydroxorhodium-
(I) derivatives (X ) OH) react with acetic acid and
phenol at room temperature to give the corresponding
acetato (X ) O2CMe) and phenolato (X ) OPh) metal
compounds almost quantitatively.2 Moreover, these
new allenylidenerhodium(I) complexes in the presence
of CO undergo a migratory insertion of the CdCdCRPh
unit into the Rh-OR′ bond to generate γ-functionalized
alkynyl ligands.
Resu lts a n d Discu ssion
Treatment of the chloro compound 110 in benzene with
50% aqueous NaOH in the presence of [PhCH2NEt3]Cl
(TEBA) gave the hydroxo complex 2 in about 60% yield
(Scheme 1). It was possible to check the completion of
the reaction by measuring the 31P NMR spectrum of the
organic phase, in which the doublet resonance of 1
appears at 43.1 ppm and that of 2 is slightly shifted
downfield at 44.1 ppm. The procedure for the prepara-
tion of 2 is somewhat similar to that for the synthesis
of both [Rh(µ-OH)(PPh3)2]211 and [Rh(µ-OH)(PiPr3)2]2,12
which also proceeds in benzene/water under biphasic
This result together with the similar course of the
intramolecular C-C coupling reactions of vinylidene
and allenylidene complexes trans-[Rh(R)(dCdCHR′)-
(PiPr3)2]3 and trans-[Rh(R)(dCdCdCR′Ph)(PiPr3)2]4 en-
forced our interest to prepare also the hydroxovin-
ylidenerhodium derivatives and to use them as starting
materials for other vinylidenerhodium compounds. In
this article we describe the synthesis of trans-[Rh(OH)-
(dCdCRR′)(PiPr3)2] and illustrate that the hydroxo
ligand of these compounds can be replaced by not only
trifluoroacetate, phenolate, and phenylacetylide but also
(5) (a) Sonogashira, K.; Fujikura, Y.; Yatake, T.; Toyoshima, N.;
Takahashi, S.; Hagihara, N. J . Organomet. Chem. 1978, 145, 101-
108. (b) Sonogashira, K.; Kataoka, S.; Takahashi, S.; Hagihara, N. J .
Organomet. Chem. 1978, 160, 319-327. (c) Sonogashira, K.; Ohga, K.;
Takahashi, S.; Hagihara, N. J . Organomet. Chem. 1980, 188, 237-
243. (d) Hagihara, N.; Sonogashira, K.; Takahashi, S. Adv. Polym. Sci.
1981, 41, 149-179.
(6) Brady, M.; Weng, W.; Zhou, Y.; Seyler, J . W.; Amoroso, A. J .;
Arif, A. M.; Bo¨hme, M.; Frenking, G.; Gladysz, J . A. J . Am. Chem. Soc.
1997, 119, 775-788 and references therein.
(7) Le Narvour, N.; Toupet, L.; Lapinte, C. J . Am. Chem. Soc. 1995,
117, 7129-7138.
(8) (a) Fyfe, H. B.; Mlekuz, M.; Zargarian, D.; Taylor, N. J .; Marder,
T. B. J . Chem. Soc., Chem. Commun. 1991, 188-189. (b) Stang, P. J .;
Tykwinski, R. J . Am. Chem. Soc. 1992, 114, 4411-4412. (c) Bruce, M.
I.; Hinterding, P.; Tiekink, E. R. T.; Skelton, B. W.; White, A. H. J .
Organomet. Chem. 1993, 450, 209-218. (d) Woodworth, B. E.; White,
P. S.; Templeton, J . L. J . Am. Chem. Soc. 1997, 119, 828-829. (e) Akita,
M.; Chung, M.-C.; Sakurai, A.; Terada, M.; Tanaka, M.; Moro-oka, Y.
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(9) Reviews: (a) Beck, W.; Niemer, B.; Wieser, M. Angew. Chem.
1993, 105, 969-996; Angew. Chem., Int. Ed. Engl. 1993, 32, 923-950.
(b) Lang, H. Angew. Chem. 1994, 106, 569-572; Angew. Chem., Int.
Ed. Engl. 1994, 33, 547-550.
2-
by the C4 dianion. Despite the great achievements
made by Sonogashira,5 Gladysz,6 Lapinte,7 and others8,9
in obtaining transition-metal complexes with bridging
C4 (and more general Cn) ligands, there is to the best of
our knowledge no dinuclear compound known in which
(1) Vinylidene Transition-Metal Complexes. 45. Part 44: Gru¨nwald,
C.; Laubender, M.; Wolf, J .; Werner, H. J . Chem. Soc., Dalton Trans.,
in press.
(2) Werner, H.; Wiedemann, R.; Laubender, M.; Wolf, J .; Wind-
mu¨ller, B. J . Chem. Soc., Chem. Commun. 1996, 1413-1414.
(3) (a) Werner, H.; Wiedemann, R.; Steinert, P.; Wolf, J . Chem. Eur.
J . 1997, 3, 127-137. (b) Wiedemann, R.; Fleischer, R.; Stalke, D.;
Werner, H. Organometallics 1997, 16, 866-870.
(4) (a) Wiedemann, R.; Steinert, P.; Gevert, O.; Werner, H. J . Am.
Chem. Soc. 1996, 118, 2495-2496. (b) Werner, H. J . Chem. Soc., Chem.
Commun. 1997, 903-910.
(10) Garcia Alonso, F. J .; Ho¨hn, A.; Wolf, J .; Otto, H.; Werner, H.
Angew. Chem. 1985, 97, 401-402; Angew. Chem., Int. Ed. Engl. 1985,
24, 406-407.
(11) Grushin, V. V.; Kuznetsov, V. F.; Bensimon, C.; Alper, H.
Organometallics 1995, 14, 3927-3932.
S0276-7333(97)01078-9 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 02/27/1998

Rh Complexes Containing a C2RhC4RhC2 Chain
Organometallics, Vol. 17, No. 6, 1998 1203
Sch em e 1a
Sch em e 2a
a
L ) PiPr3.
Sch em e 3a
a
L ) PiPr3.
conditions. It is important to note, however, that the
preparation of the hydroxovinylidene complex fails in
the absence of TEBA as a phase-transfer reagent.
Compound 2 is a red-violet, very air-sensitive solid
which is soluble in most organic solvents, including
pentane, and decomposes at 40 °C. Typical spectro-
scopic features of 2 are the weak OH stretching band
at 3650 cm-1 in the IR, the doublet-of-triplets resonance
1
for the dCHPh proton at 1.84 ppm in the H NMR, and
the low-field signals (both doublet-of-triplets) for the R-C
and â-C vinylidene carbon atoms at 298.3 and 113.8
ppm in the 13C NMR spectrum.
a
If the starting material 1 was treated instead of 50%
aqueous NaOH with a 50% solution of NaOD in D2O,
the â-position of the vinylidene unit was 94% deuterated
to give 2-d 2 as the main product. In the 1H NMR
spectrum of 2-d 2 the resonance corresponding to the
dCHPh proton had nearly disappeared and a broad
singlet is observed in the 2H NMR spectrum at 1.86
ppm. Compound 2 reacted with D2O to yield instead of
2-d 2 the monodeuterated derivative 2-d , indicating that
the vinylidene proton is not acidic enough to undergo a
H/D exchange in the absence of base.
The dimethylvinylidene complex 3, which has recently
been prepared in an unconventional way by using an
olefin instead of an alkyne as the precursor for the C2
ligand,13 also reacted with 50% aqueous NaOH in the
presence of TEBA under biphasic conditions to give the
Rh-OH derivative 4 in practically quantitative yield.
The red-violet solid, which is quite air-sensitive, is
thermally more stable than 2 and melts at 93 °C with
decomposition. The IR and NMR spectroscopic data for
4 are in full agreement with the structural proposal
shown in Scheme 2 and thus deserve no further com-
ment.
L ) PiPr3.
violet solid which can be handled in air for a short period
of time and has been characterized by both elemental
analysis and spectroscopic means.
Phenylacetylene behaves similarly to phenol and upon
addition to a solution of 2 in pentane at low temperature
yields the alkynylvinylidenerhodium(I) compound 7
(Scheme 3). This was originally prepared from either
13a or [Rh(η3-CH2Ph)(PiPr3)2]15 and subsequently used
for the preparation of the isomeric π-butadienyl complex
[Rh(2,3,4-η)-PhCHCHC)CHPh)(PiPr3)2].3a
Both the hydroxorhodium(I) derivatives 2 and 4, on
treatment with 0.5 molar equiv of Ph3SnCtCCtCSnPh3,
afforded the complexes 8 and 9 (Scheme 4) in 75-80%
yield. Dinuclear rhodium compounds containing a
“naked” C4 bridge are not without precedent and have
been prepared in our laboratory either from buta-1,4-
diyne16 or from Me3SiCtCCtCSiMe312 as precursors of
the C4 unit. The formation of Ph3SnOH as a secondary
product in the reaction of 2 and 4 with the bis-
stannylated diyne has been substantiated by compari-
son of the IR and NMR data with those of an authentic
sample.17 Compounds 8 and 9 are green, air-sensitive
crystalline materials which in the solid state can be
stored at 0 °C but slowly decompose in solution. The
correct composition of 8 and 9 has been proved by
elemental analysis as well as mass spectrometry.
Since it is possible that compounds of the general
composition trans-[Rh(CtCR)(dCdCHR′)(PiPr3)2] are
in equilibrium with the corresponding isomers trans-
Like the related allenylidenerhodium(I) derivatives
trans-[Rh(OH)(dCdCdCRPh)(PiPr3)2],2 compound 2 af-
forded on treatment with equimolar amounts of CF3-
CO2H and PhOH the trifluoroacetato and phenolato
complexes 5 and 6 almost quantitatively (Scheme 3).
An alternative route to 5 has already been described
using [Rh(η2-O2CCF3)(PiPr3)2] and PhCtCH as the
starting materials.14 The phenolato complex is a red-
(12) Gevert, O.; Wolf, J .; Werner, H. Organometallics 1996, 15,
2806-2809.
(15) Werner, H.; Scha¨fer, M.; Nu¨rnberg, O.; Wolf, J . Chem. Ber.
1994, 127, 27-38.
(16) Rappert, T.; Nu¨rnberg, O.; Werner, H. Organometallics 1993,
(13) Wolf, J .; Lass, R. W.; Manger, M.; Werner, H. Organometallics
1995, 14, 2649-2651.
12, 1359-1364.
(14) Scha¨fer, M.; Wolf, J .; Werner, H. J . Organomet. Chem. 1995,
485, 85-100.
(17) Kushlefsky, B.; Simmons, I.; Ross, A. Inorg. Chem. 1963, 2,
187-189.

1204 Organometallics, Vol. 17, No. 6, 1998
Gil-Rubio et al.
Sch em e 4a
C4 (see Table 1) are comparable to those of the mono-
nuclear complex trans-[RhCl(dCdCHMe)(PiPr3)2]
(1.775(6) and 1.32(1) Å),19 which illustrates that the C4
unit like chloride is predominantly a σ-donor ligand.
With regard to the bonding pattern in 9, it should be
mentioned that the Rh-C3 bond length is almost
identical with the Rh-CO distance in [{Rh(CO)(PiPr3)2}2-
(µ-C4)] (1.832(4) Å),12 indicating that in agreement with
theoretical calculations20 the π-acceptor character of CO
and vinylidenes is quite similar.
Since it has been shown by both experimental16,21 and
theoretical studies22 that vinylidenerhodium complexes
trans-[RhX(dCdCHR)(PiPr3)2] could rearrange, depend-
ing on the anionic ligand X and the substituent R, to
the isomeric alkynylhydrido isomers [RhH(CtCR)X-
(PiPr3)2] and vice versa, the reaction of 8 toward
pyridine was investigated. From previous work it was
known21 that the sometimes very labile, five-coordinate
alkynylhydridorhodium(III) species can be trapped by
pyridine to give the more stable six-coordinate com-
pounds [RhH(CtCR)X(py)(PiPr3)2]. The dinuclear com-
plex reacted with pyridine very smoothly indeed to
afford the 1:2 adduct 10 (Scheme 4) as a beige solid in
61% yield. The most characteristic spectroscopic fea-
tures of 10 are the intense CtC stretching frequency
at 2086 cm-1 in the IR, the high-field signal for the
metal-bonded hydrogens at -17.94 ppm in the 1H NMR,
and the single resonance for the 31P nuclei at 42.1 ppm
in the 31P NMR spectrum, the latter being split into a
doublet due to Rh-P coupling. In solution, the bis-
(pyridine) adduct is rather labile and slowly decomposes
to give trans-[Rh(CtCPh)(py)(PiPr3)2].21a
a
L ) PiPr3.
Sch em e 5a
In summary, we have shown in this work that
compounds such as 8 and 9 possessing a linear C2RhC4-
RhC2 chain are accessible, provided that instead of the
well-known chlororhodium(I) derivatives 1 and 3 the
corresponding hydroxo complexes 2 and 4 are used as
starting materials. In contrast to the numerous com-
pounds of the general composition [M(OR)nLm], where
M is a d0, d1, or d2 metal center, related species with
electron-rich (d6-d10) transition metals are still rela-
tively rare.23,24 We hope that the propensity of the
allenylidene complexes trans-[Rh(OH)(dCdCdCRPh)-
(PiPr3)2] to react with acidic substrates by forming new
rhodium-element bonds2,18,25 as well as the first results
on the reactivity of 2 and 4 reported here will spur
further activities in this field.
a
L ) PiPr3.
[Rh(CtCR′)(dCdCHR)(PiPr3)2],18 we checked by an
NOE experiment that the product of the reaction of 2
with Ph3SnCtCCtCSnPh3 is 8 and not the isomeric
species [{Rh(CtCPh)(PiPr3)2}2(µ-CdCHCHdC)] (8′).
The results of the NOE experiment (Scheme 5) con-
firmed the vicinity of the phenyl group and the vin-
ylidenic hydrogen in the molecule and thus excluded
isomer 8′.
The result of the X-ray crystal structure analysis of
9 is shown in Figure 1. The two Rh(dCdCMe2)(PiPr3)2
fragments are bridged by an almost perfectly linear C4
unit, and since the RhdCdC moieties such as the
CdCdC backbone of allenes are also linear, the skeleton
of 9 represents a linear 10-atom C2RhC4RhC2 chain. The
midpoint of the C-C single bond of the C4 bridge lies
on a crystallographic center of symmetry, and therefore,
only four halves of the molecule are found in the unit
cell. As a consequence, both P2RhC2 planes lie parallel
in the crystal and not perpendicular as one would expect
due to the bulkiness of the phosphine ligands. Despite
the steric demand of the methyl groups at C4, the P1-
Rh-P2 axis is only slightly bent, the corresponding bond
angle being 177.10(8)°. The distances Rh-C3 and C3-
(19) Werner, H.; Garcia Alonso, F. J .; Otto, H.; Wolf, J . Z. Natur-
forsch., B 1988, 43, 722-726.
(20) (a) Schilling, B. E. R.; Hoffmann, R.; Lichtenberger, D. L. J .
Am. Chem. Soc. 1979, 101, 585-591. (b) Kostic, N. M.; Fenske, R. F.
Organometallics 1982, 1, 974-982.
(21) (a) Werner, H.; Wolf, J .; Garcia Alonso, F. J .; Ziegler, M. L.;
Serhadli, O. J . Organomet. Chem. 1987, 336, 397-411. (b) Werner,
H.; Brekau, U. Z. Naturforsch., B 1989, 44, 1438- 1446. (c) Windmu¨ller,
B.; Wolf, J .; Werner, H. J . Organomet. Chem. 1995, 502, 147-161. (d)
Werner, H.; Wiedemann, R.; Mahr, N.; Steinert, P.; Wolf, J . Chem.
Eur. J . 1996, 2, 561-569.
(22) Wakatsuki, Y.; Koga, N.; Werner, H.; Morokuma, K. J . Am.
Chem. Soc. 1997, 119, 360-366.
(23) Review: Bryndza, H. E.; Tam, W. Chem. Rev. 1988, 88, 1163-
1188.
(24) For the synthesis of iridium analogues of 2 see: Ho¨hn, A.;
Werner, H. J . Organomet. Chem. 1990, 382, 255-272.
(25) Laubender, M. Dissertation, Universita¨t Wu¨rzburg, in prepara-
tion.
(18) (a) Scha¨fer, M. Dissertation, Universita¨t Wu¨rzburg, 1994. (b)
Wiedemann, R. Dissertation, Universita¨t Wu¨rzburg, 1995.

Rh Complexes Containing a C2RhC4RhC2 Chain
Organometallics, Vol. 17, No. 6, 1998 1205
F igu r e 1. Molecular structure (ORTEP plot) of compound 9.
Ta ble 1. Selected Bon d Dista n ces a n d An gles w ith
Esd ’s for Com p ou n d 9a
days at -60 °C. Red-violet crystals precipitated, which were
filtered, washed twice with 2 mL portions of pentane (-40 °C),
and dried: yield 114 mg (60%); mp 40 °C dec; IR (C6H6) ν-
Bond Distances (Å)
(OH) 3650, ν(CdC), 1641, 1616, 1593, 1570 cm-1 1H NMR
;
Rh-C3
Rh-C1
Rh-P1
Rh-P2
C1-C2
1.857(7)
2.023(7)
2.324(2)
2.333(2)
1.221(9)
C2-C2*
C3-C4
C4-C6
C4-C5
1.38(1)
1.305(9)
1.51(1)
1.51(1)
(C6D6, 400 MHz) δ 7.29 (d, J (HH) ) 7.2 Hz, 2H, ortho H of
C6H5), 7.13 (t, J (HH) ) 8.0 Hz, 2H, meta H of C6H5), 6.87 (t,
J (HH) ) 7.2 Hz, 1H, para H of C6H5), 2.50 (m, 6H, PCHCH3),
1.84 (dt, J (RhH) ) 1.6 Hz, J (PH) ) 3.2 Hz, 1H, RhdCdCH),
1.29 (dvt, N ) 13.2 Hz, J (HH) ) 6.8 Hz, 36H, PCHCH3), 0.64
(br t, J (PH) ) 5.2 Hz, 1H, OH); 13C{1H} NMR (C6D6, 100.6
MHz) δ 298.3 (dt, J (RhC) ) 47.2 Hz, J (PC) ) 17.1 Hz, Rh)C),
128.4, 124.9, 124.1 (all s, CH of C6H5, the signal of ipso C
overlaps with the signal of the solvent), 113.8 (dt, J (RhC) )
13.1 Hz, J (PC) ) 6.0 Hz, RhdCdC), 23.2 (vt, N ) 18.9 Hz,
PCHCH3), 20.2 (s, PCHCH3); 31P{1H} NMR (C6D6, 162.0 MHz)
δ 44.1 (d, J (RhP) ) 146.1 Hz). Anal. Calcd for C26H49OP2Rh:
C, 57.56; H, 9.10. Found: C, 57.86; H, 9.13. EI MS (70 eV):
m/z 542 (0.3, M+), 440 (1, M+ - PhC2H), 422 (0.4, M+ - PhC2H
- H2O), 160 (59, PiPr3+), 118 (87, PiPr2H+), 76 (100, PiPrH2+).
Bond Angles (deg)
C3-Rh-C1
C3-Rh-P1
C1-Rh-P1
C3-Rh-P2
C1-Rh-P2
P1-Rh-P2
172.1(3)
91.5(2)
88.7(2)
91.2(2)
88.7(2)
177.10(8)
C2-C1-Rh
C1-C2-C2*
C4-C3-Rh
C3-C4-C6
C3-C4-C5
C6-C4-C5
173.1(7)
176(1)
174.9(6)
121.6(7)
121.9(7)
116.5(6)
a
The midpoint of the bond C2-C2* is a center of symmetry;
therefore, the corresponding bond distances Rh-C1/Rh*-C1* etc.
and bond angles P1-Rh-P2/P1*-Rh*-P2* etc. are identical.
Exp er im en ta l Section
Rea ction of 2 w ith CCl4. A solution of 2 (15 mg, 0.03
mmol) in C6D6 (0.6 mL) was treated with CCl4 (4 µL, 0.04
mmol) at room temperature. The reaction mixture was stirred
All reactions were carried out under an inert atmosphere
of argon by use of Schlenk techniques. The starting materials
1
at room temperature for 1.5 h. The H and 31P NMR spectra
1,10 3,13 and Ph3SnCtCCtCSnPh3 were prepared as de-
26
of the blue-green solution showed a quantitative conversion
scribed in the literature. NMR spectra were recorded at room
temperature on Bruker AC 200 and Bruker AMX 400 instru-
ments (abbreviation: dvt ) doublet of virtual triplets) and IR
spectra on Perkin-Elmer 1420 and Bruker IFS 25 spectrom-
eters. Melting points were determined by DTA. Electron
impact mass spectra were obtained on Finnigan MAT 90 and
MAT 8200 instruments; electrospray ionization mass spectra
were obtained on a Finnigan MAT TSQ 7000 instrument
operating in the positive-ion mode (m/z ) relative abundance).
P r ep a r a tion of tr a n s-[Rh (OH)(dCdCHP h )(P iP r 3)2] (2).
A solution of 1 (198 mg, 0.35 mmol) in 10 mL of benzene was
treated with 3 mL of 50% aqueous NaOH (saturated with
argon) and TEBA (10 mg). The reaction mixture was vigor-
ously stirred for 90 min at room temperature, and the
completion of the reaction was checked by measuring the 31P
NMR spectrum of the organic phase. The organic phase was
then transferred to another Schlenk tube, and the aqueous
phase was extracted with 5 mL of benzene. The combined
benzene solutions were brought to dryness in vacuo, and the
residue was extracted with 10 mL of pentane. The extract
was concentrated to ca. 2 mL in vacuo and then stored for 4
of 2 into 1.
P r ep a r a tion of tr a n s-[Rh (OD)(dCdCHP h )(P iP r 3)2] (2-
d ). A solution of 2 (10 mg, 0.02 mmol) in 0.6 mL of C6D6 was
treated with D2O (0.4 mL) for 15 min at room temperature.
After removal of the aqueous phase, H and 31P NMR spectra
1
were measured. A single compound was observed, whose NMR
and IR data were very similar to those of 2. The most
significant differences between the spectra of 2 and 2-d were
the absence of the triplet of the OH proton in the 1H NMR
spectrum and the absence of the ν(OH) band in the IR
spectrum of the C6D6 solution. IR: ν(CdC) 1641, 1616, 1593
cm-1 1H NMR (C6D6, 200 MHz): δ 7.27 (d, J (HH) ) 7.3 Hz,
.
2H, ortho H of C6H5), 7.13 (t, J (HH) ) 7.3 Hz, 2H, meta H of
C6H5), 6.87 (t, J (HH) ) 7.3 Hz, 1H, para H of C6H5), 2.48 (m,
6H, PCHCH3), 1.80 (dt, J (RhH) ) 1.6 Hz, J (PH) ) 3.1 Hz,
1H, RhdCdCH), 1.27 (dvt, N ) 13.4 Hz, J (HH) ) 6.9 Hz, 36H,
PCHCH3). 31P{1H} NMR (C6D6, 81.0 MHz): δ 44.6 (d, J (RhP)
) 146.9 Hz).
P r ep a r a tion of tr a n s-[Rh (OD)(dCdCDP h )(P iP r 3)2] (2-
d 2). This was prepared analogously as described for 2, using
a solution of 1 (123 mg, 0.22 mmol) in 7 mL of C6H6, 1.5 mL
of a 50% solution of NaOD in D2O (saturated with argon), and
TEBA (6 mg) as starting materials: red-violet solid; yield 33
mg (28%). By integration of the signals in the 1H NMR
(26) Bre´fort, J . L.; Corriu, J . P.; Gerbier, P.; Gue´rin, C.; Henner, B.
J . L.; J ean, A.; Kuhlmann, T.; Garnier, F.; Yassar, A. Organometallics
1992, 11, 2500-2506.

1206 Organometallics, Vol. 17, No. 6, 1998
Gil-Rubio et al.
spectrum (in C6D6), a D/H ratio of 17/1 (94% D) at the â-carbon
position of the vinylidene ligand was determined. A triplet
was observed at δ 0.68, indicating that a small amount of
trans-[Rh(OH)(CdCDPh)(PiPr3)2] had also been formed by D/H
exchange with solvent water; this triplet disappeared upon
treatment with D2O. Characteristic spectroscopic data for
2-d 2: IR (C6H6) ν(CdC) 1614, 1593, 1570 cm-1; 1H NMR (C6D6,
200 MHz) δ 7.26 (d, J (HH) ) 6.9 Hz, 2H, ortho H of C6H5),
7.12 (t, J (HH) ) 7.7 Hz, 2H, meta H of C6H5), 6.87 (t, J (HH)
) 7.1 Hz, 1H, para H of C6H5), 2.48 (m, 6H, PCHCH3), 1.26
PCHCH3); 31P{1H} NMR (C6D6, 162.0 MHz) δ 42.6 (d, J (RhP)
) 141.5 Hz); EI MS (70 eV) m/z 618 (0.4, M+), 525 (2, [Rh(C2-
HPh)(PiPr3)2]+), 423 (2, [Rh(PiPr3)2]+), 160 (31, PiPr3+), 118
(64, PiPr2H+), 76 (100, PiPrH2+). Anal. Calcd for C32H53OP2-
Rh: C, 62.13; H, 8.64. Found: C, 61.89; H, 8.73.
P r epar ation of tr a n s-[Rh (CtCP h )(dCdCHP h )(P iP r 3)2]
(7). This compound was prepared analogously to 6, using 2
(52 mg, 0.10 mmol) and phenylacetylene (11 µL, 0.10 mmol)
as starting materials. The green solid was washed twice with
1.5 mL portions of pentane (-40 °C) and dried: yield 58 mg
(97%). The NMR data of the compound were identical with
those reported for 7 in the literature.14
2
(dvt, N ) 13.5 Hz, J (HH) ) 6.9 Hz, 36H, PCHCH3); H NMR
(C6H6, 61.4 MHz, δ[C6D6] 7.15 ppm was used as reference) δ
1.86 (br s, RhdCdCDPh); 13C{1H} NMR (C6D6, 100.6 MHz) δ
128.4, 124.9, 124.2 (all s, CH of C6H5, the signal of ipso C
overlaps with the signal of the solvent), 23.2 (vt, N ) 18.9 Hz,
PCHCH3), 20.2 (s, PCHCH3), the signals of the R and â
vinylidenic carbons are not observed; 31P{1H} NMR (C6D6, 81.0
MHz) δ 44.4 (d, J (RhP) ) 145.0 Hz).
P r ep a r a tion of tr a n s,tr a n s-[{Rh (dCdCHP h )(P iP r 3)2}2-
(µ-C4)] (8). A solution of 2, prepared from 1 (180 mg, 0.32
mmol) as described above, in 15 mL of pentane was treated
with Ph3SnCtCCtCSnPh3 (109 mg, 0.15 mmol) at -78 °C.
With continuous stirring, the mixture was slowly warmed to
0 °C and stirred at this temperature for 20 min; during that
time, a change of color from red-violet to green occurred. The
solution was concentrated to ca. 4 mL in vacuo, and ether was
added (2 mL); then, the solution was chromatographed on
Al2O3 (neutral, activity grade V, column length 13 cm, column
diameter 2 cm) at 0 °C. With diethyl ether/pentane (1:4), a
green fraction was eluted, which was brought to dryness in
vacuo. A second brownish fraction was eluted with acetone,
which after removal of the solvent gave a light-brown solid.
This was identified by comparison of the spectroscopic data
with those of an authentic sample of Ph3SnOH.17 The green
fraction was brought to dryness in vacuo; the residue was
washed three times with 2 mL portions of pentane (-40 °C)
and dried in vacuo to afford a green solid which was pure by
NMR spectroscopy: yield 132 mg (75%). Analytically pure 8
was obtained by recrystallization of the green solid from
pentane: mp 84 °C dec; IR (C6H6) ν(CdC) 1630, 1610, 1590,
P r ep a r a tion of tr a n s-[Rh (OH)(dCdCMe2)(P iP r 3)2] (4).
A solution of 3 (118 mg, 0.23 mmol) in 5 mL of benzene was
treated with 1.5 mL of aqueous NaOH (saturated with argon)
and TEBA (5 mg). The reaction mixture was vigorously stirred
for 2.5 h at room temperature, and the completion of the
reaction was checked by measuring the 31P NMR spectrum of
the organic phase. The aqueous phase was removed, and the
organic phase was washed four times with 7 mL portions of
degassed water. The benzene solution was brought to dryness
in vacuo. The residue was dissolved in 5 mL of benzene, and
after the solvent was removed a red-violet solid was isolated.
It was washed twice with 2 mL portions of pentane (-40 °C):
yield 109 mg (96%); mp 93 °C dec; IR (C6H6) ν(CdC) 1675 cm-1
;
1H NMR (C6D6, 200 MHz) δ 2.46 (m, 6H, PCHCH3), 1.79 (t,
J (PH) ) 2.0 Hz, 6H, RhdCdC(CH3)2), 1.33 (dvt, N ) 13.1 Hz,
J (HH) ) 6.9 Hz, 36H, PCHCH3), 0.63 (br t, 1H, OH); 13C{1H}
NMR (C6D6, 50.3 MHz) δ 296.6 (dt, J (RhC) ) 45.4 Hz, J (PC)
) 17.5 Hz, RhdC), 107.1 (dt, J (RhC) ) 12.6 Hz, J (PC) ) 5.8
Hz, RhdCdC), 22.9 (vt, N ) 17.9 Hz, PCHCH3), 20.2 (s,
PCHCH3), 7.5 (s, RhdCdC(CH3)2); 31P{1H} NMR (C6D6, 81.0
1
1565 cm-1, ν(CtC) not located; H NMR (C6D6, 200 MHz) δ
7.25 (d, J (HH) ) 7.4 Hz, 4H, ortho H of C6H5), 7.10 (t, J (HH)
) 7.4 Hz, 4H, meta H of C6H5), 6.87 (t, J (HH) ) 7.4 Hz, 2H,
para H of C6H5), 2.68 (m, 12H, PCHCH3), 1.63 (t, J (PH) ) 3.6
Hz, 2H, RhdCdCH), 1.36 (dvt, N ) 13.4 Hz, J (HH) ) 6.8 Hz,
72H, PCHCH3); 13C{1H} NMR (C6D6, 100.6 MHz) δ 310.0 (dt,
J (RhC) ) 49.3 Hz, J (PC) ) 16.1 Hz, RhdC), 128.5 (s, CH of
C6H5), 126.4 (s, ipso C of C6H5), 125.7, 124.6 (both s, CH of
C6H5), 123.1 (dt, J (RhC) ) 37.2 Hz, J (PC) ) 21.3 Hz, RhCtC,
the signal of Rh-CtC overlaps with the signal of the solvent),
116.0 (dt, J (RhC) ) 12.1 Hz, J (PC) ) 6.0 Hz, RhdCdCH), 25.7
(vt, N ) 20.6 Hz, PCHCH3), 20.7 (s, PCHCH3); 31P{1H} NMR
(C6D6, 162.0 MHz) δ 47.6 (d, J (RhP) ) 135.8 Hz); ESI MS
(acetonitrile/acetone) m/z 1099 (8, MH+ and M[13C]+), 1098 (11,
M+), 997 (16, MH+ - PhC2H), 996 (13, M+ - PhC2H), 525 (69,
[Rh(C2HPh)(PiPr3)2]+), 423 (100, [Rh(PiPr3)2]+). Anal. Calcd
for C56H96P4Rh2: C, 61.20; H, 8.80. Found: C, 60.86; H, 8.66.
P r ep a r a tion of tr a n s,tr a n s-[{Rh (dCdCMe2)(P iP r 3)2}2-
(µ-C4)] (9). A solution of 4 (85 mg, 0.17 mmol) in 5 mL of
pentane was treated with Ph3SnCtCCtCSnPh3 (64 mg, 0.09
mmol) at -78 °C. With continuous stirring, the mixture was
slowly warmed to room temperature and stirred at this
temperature for 20 min. A change of color from red-violet to
green occurred. The solvent was removed in vacuo, and 15
mL of pentane (-78 °C) was added to the residue. The cold
green solution was filtered through a cotton pad, and the
filtrate was brought to dryness in vacuo. The residue was
dissolved in 4 mL of acetone, and after the solution was stored
for 2 days at -20 °C green crystals precipitated. They were
washed with 3 mL portions of acetone (-40 °C) and dried:
yield 68 mg (79%); mp 90 °C dec; IR (hexane) ν(CdC) 1675
cm-1 ν(CtC) not located; 1H NMR (C6D6, 400 MHz) δ 2.65 (m,
12H, PCHCH3), 1.74 (t, J (PH) ) 2.4 Hz, 12H, RhdCdC(CH3)2),
1.38 (dvt, N ) 13.6 Hz, J (HH) ) 7.2 Hz, 72H, PCHCH3); 13C-
{1H} NMR (C6D6, 100.6 MHz) δ 308.6 (dt, J (RhC) ) 46.3 Hz,
J (PC) ) 17.1 Hz, RhdC), 127.4 (d, J (RhC) ) 10.1 Hz, RhCtC),
123.8 (dt, J (RhC) ) 38.2 Hz, J (PC) ) 19.1 Hz, RhCtC), 109.2
MHz) δ 45.0 (d, J (RhP) ) 148.2 Hz). Anal. Calcd for C22H49
OP2Rh: C, 53.44; H, 9.99. Found: C, 53.03; H, 9.75.
-
P r ep a r a t ion of tr a n s-[R h (η1-O2CCF 3)(dCdCH P h )-
(P iP r 3)2] (5). A solution of 2 (29 mg, 0.05 mmol) in 1.5 mL of
C6D6 was treated with an equimolar amount of CF3CO2H and
stirred for 5 min at room temperature. According to the 1H
and 31P{1H} NMR spectra, a quantitative conversion of 2 to 5
occurred. The solvent was removed in vacuo; the green-blue
residue was washed twice with 1 mL portions of pentane (-40
°C) and dried in vacuo: yield 30 mg (88%). The NMR data of
the compound were identical with those of 5 reported in the
literature.14
P r ep a r a t ion of tr a n s-[R h (OP h )(dCdCH P h )(P iP r 3)2]
(6). A solution of 2 (119 mg, 0.22 mmol) in 5 mL of pentane
was treated with phenol (17 mg, 0.18 mmol) at -78 °C. The
reaction mixture was slowly warmed to room temperature,
stirred for 1 h, and brought to dryness in vacuo. The residue
was dissolved in 2 mL of acetone and the solution stored for 4
days at -20 °C. Red-violet crystals precipitated, which were
washed three times with 2 mL portions of acetone (-20 °C)
and dried in vacuo: yield 90 mg (67%); mp 85 °C dec; IR (C6H6)
1
ν(CdC) 1645, 1625, 1575 cm-1; H NMR (C6D6, 200 MHz) δ
7.32-7.09 (m, 6H, ortho and meta H of C6H5 + meta H of
C6H5O), 6.87 (t, J (HH) ) 7.3 Hz, 1H, para H of C6H5), 6.70 (t,
J (HH) ) 7.2 Hz, 1H, para H of C6H5O), 6.67 (d, J (HH) ) 7.8
Hz, 2H, ortho H of C6H5O), 2.30 (m, 6H, PCHCH3), 1.76 (dt,
J (RhH) ) 1.5 Hz, J (PH) ) 3.3 Hz, 1H, RhdCdCH), 1.22 (dvt,
N ) 13.6 Hz, J (HH) ) 7.0 Hz, 36H, PCHCH3); 13C{1H} NMR
(C6D6, 100.6 MHz) δ 298.8 (dt, J (RhC) ) 53.3 Hz, J (PC) ) 18.1
Hz, Rh)C), 168.5 (s, ipso C of C6H5O), 129.1, 128.6 (both s,
CH of C6H5), 126.9 (s, ipso C of C6H5), 125.2, 124.8, 120.3 (all
s, CH of C6H5O and C6H5), 114.0-113.7 (m, RhdC)CH and
CH of C6H5), 23.9 (vt, N ) 17.9 Hz, PCHCH3), 20.3 (s,

Rh Complexes Containing a C2RhC4RhC2 Chain
Organometallics, Vol. 17, No. 6, 1998 1207
(dt, J (RhC) ) 12.1 Hz, J (PC) ) 6.0 Hz, RhdCdC(CH3)2), 25.3
(vt, N ) 19.9 Hz, PCHCH3), 20.7 (s, PCHCH3), 6.4 (s, CdC-
(CH3)2); 31P{1H} NMR (C6D6, 162.0 MHz) δ 47.9 (d, J (RhP) )
138.0 Hz); ESI MS (methanol/acetone) m/z 1001 (1, [M - H]+),
477 (100, [Rh(C2Me2)(PiPr3)2]+). Anal. Calcd for C48H96P4-
Rh2: C, 57.48; H, 9.65. Found: C, 57.28; H, 9.67.
0.753 mm-1 (Mo KR, λ ) 0.710 73 Å), maximum 2θ ) 46°, ω/θ
scan, graphite monochromator, Zr filter (factor 16.4), T )
293(2) K; 3923 reflections scanned, 3605 unique (R(int) )
0.0415), 2591 observed (I > 2σ(I)), LP and empirical absorption
correction (ψ-scans, minimum transmission 87.30%); direct
methods (SHELXS-8627), 258 parameters, reflex/parameter
ratio 13.97; R1 ) 0.0486, wR2 ) 0.0834 for 2591 observed
reflections and R1 ) 0.0826, wR2 ) 0.1023 for all 3603 data
reflections; residual electron density +0.484/-0.486 e Å-3. The
asymmetric unit contains only half of the molecule; the second
half was generated by the symmetry instruction -x, -y, -z.
Atoms generated by symmetry in Figure 1 are marked with
asterisks. The positions of all hydrogen atoms were calculated
according to ideal geometry and refined by full-matrix least
squares on F2 using the riding method (weighting scheme
P r ep a r a t ion of tr a n s,tr a n s-[{R h (H )(CtCP h )(p y)-
(P iP r 3)2}2(µ-C4)] (10). A solution of 8 (95 mg, 0.087 mmol)
in 10 mL of pentane was treated with pyridine (1 mL), and
the mixture was stirred at 40 °C for 1 h. The brownish yellow
solution was then filtered through a cotton pad and brought
to dryness in vacuo. The residue was dissolved in 1 mL of
diethyl ether, and upon addition of pentane at room temper-
ature, a beige solid precipitated. After the suspension was
stored at -20 °C for 2 h, the mother liquor was separated and
the solid washed twice with 2 mL portions of cold pentane (-20
°C) and dried in vacuo. A second portion of the beige solid
was obtained from the mother liquor when it was concentrated
and stored at -20 °C: yield 66 mg (61%); mp 58 °C dec; IR
applied in the last cycle w-1 ) σ2Fo + (0.0119P)2 + 4.0625P,
2
where P ) (Fo + 2Fc2)/3, SHELXL-9327).
2
Ack n ow led gm en t . We thank the Deutsche For-
schungsgemeinschaft (Grant No. SFB 347) and the
Fonds der Chemischen Industrie. J .G.-R. is grateful to
the Spanish Ministerio de Educacio´n y Cultura and to
the European Commission (Contract No. ERBFMBICT-
960698) for a postdoctoral grant. We also gratefully
acknowledge support by Mrs. Schedl and C. P. Kneis
(DTA and elemental analysis), Mrs. M. L. Scha¨fer and
Dr. W. Buchner (NMR measurements), Dr. G. Lange
and Mr. F. Dadrich (EI mass spectra), and Dr. M.
Herderich (ESI mass spectra) and Degussa AG for
various gifts of chemicals.
(Nujol-polyethylene) ν(CtC) 2086, ν(CdC) 1594, 1569 cm-1
;
1H NMR (C6D6, 400 MHz) δ 9.41 (br s, 4H, ortho H of C5H5N),
7.72 (d, J (HH) ) 7.5 Hz, 4H, ortho H of C6H5), 7.19 (t, J (HH)
) 7.6 Hz, 4H, meta H of C6H5), 6.98 (t, J (HH) ) 7.3 Hz, 2H,
para H of C6H5), 6.95 (t, J (HH) ) 7.1 Hz, 2H, para H of
C5H5N), 6.63 (br t, 4H, meta H of C5H5N), 2.98 (m, 12H,
PCHCH3), 1.32 (dvt, N ) 13.2 Hz, J (HH) ) 6.7 Hz, 72H,
PCHCH3), -17.94 (dt, J (RhH) ) 17.0 Hz, J (PH) ) 14.0 Hz,
2H, RhH); 13C{1H} NMR (C6D6, 100.6 MHz) δ 153.1 (br s, ortho
C of C5H5N), 135.6 (s, CH of C6H5 or C5H5N), 131.3 (s, ipso C
of C6H5), 130.7, 128.4 (both s, CH of C6H5 or C5H5N), 124.5
(m, RhCtC), 124.1, 123.4 (both s, CH of C6H5 or C5H5N), 110.8,
99.3 (both d, J (RhC) ) 7.0 Hz, RhCtC), 96.9 (m, RhCtC),
25.7 (vt, N ) 21.5 Hz, PCHCH3), 19.9 (s, PCHCH3); 31P{1H}
NMR (C6D6, 162.0 MHz) δ 42.1 (d, J (RhP) ) 98.3 Hz). Anal.
Calcd for C66H106N2P4Rh2: C, 63.04; H, 8.50; N, 2.24. Found:
C, 62.66; H, 8.73; N, 2.24.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data and refinement parameters, bond lengths and angles, and
positional and thermal parameters for 9 (5 pages). Ordering
information is given on any current masthead page.
X-r a y Str u ctu r a l An a lysis of 9. Single crystals were
grown from Et2O at -20 °C; the crystal size was 0.08 × 0.12
× 0.16 mm. Crystal data (from 24 reflections, 6° < θ < 13°):
triclinic, space group P1h (No. 2); a ) 7.900(1) Å, b ) 10.948(1)
Å, c ) 16.541(2) Å, R ) 109.33(1)°, â ) 91.70(1)°, γ )
93.62(1)°, V ) 1345.3(3) Å3, dcalcd ) 1.238 g cm-3; µ(Mo KR) )
OM9710780
(27) (a) Sheldrick, G. M. SHELXS-86; University of Go¨ttingen,
Go¨ttingen, Germany, 1986. (b) Sheldrick, G. M. SHELXL-93; Univer-
sity of Go¨ttingen, Go¨ttingen, Germany, 1993.