A series of novel binuclear iron-rhodium complexes prepared from ethynylferrocene

Article abstract of DOI:10.1021/om960825a

The chlororhodium(I) compound [RhCl(PiPr₃)₂]₂ (1) reacts with ethynylferrocene (2) by oxidative addition to give the alkynyl(hydrido)rhodium(III) complex [RhH(C=CFc)Cl(PiPr₃)₂] (3) almost quantitatively [Fc = (η⁵-C₅H₄-)Fe(η⁵-C ₅H₅)]. Compound 3 is slowly converted in benzene at room temperature to the vinylidene isomer trans-[RhCl(=C=CHFc)(PiPr₃)₂] (4). Treatment of 4 with Grignard reagents RMgX affords the phenyl- and vinylrhodium(I) derivatives trans-[Rh(R)(=C=CHFc)(PiPr₃)₂] (5, 6) of which the latter (R = CH=CH₂) rearranges to the isomeric η³-2-4-butadienyl complex [Rh(η³-trans-CH₂CHC=CHFc)(PiPr₃) ₂] (8). The corresponding η³-allyl compound [Rh(η³-anti-CH₂CH=CHFc)(PiPr₃)₂] (7) is obtained from 4 and CH₃MgI, possibly via trans-[Rh(CH₃)(=C=CHFc)(PiPr₃)₂] as an intermediate. The X-ray crystal structure analysis of 7 confirms the anti position of the ferrocenyl group at the allylic ligand.

Full text of DOI:10.1021/om960825a

866
Organometallics 1997, 16, 866-870
A Ser ies of Novel Bin u clea r Ir on -Rh od iu m Com p lexes
P r ep a r ed fr om Eth yn ylfer r ocen e†,1
Ralf Wiedemann, Roland Fleischer, Dietmar Stalke, and Helmut Werner*
Institut fu¨r Anorganische Chemie der Universita¨t Wu¨rzburg, Am Hubland,
D-97074 Wu¨rzburg, Germany
Received September 26, 1996X
The chlororhodium(I) compound [RhCl(PiPr3)2]2 (1) reacts with ethynylferrocene (2) by
oxidative addition to give the alkynyl(hydrido)rhodium(III) complex [RhH(CtCFc)Cl(PiPr3)2]
(3) almost quantitatively [Fc ) (η5-C5H4-)Fe(η5-C5H5)]. Compound 3 is slowly converted in
benzene at room temperature to the vinylidene isomer trans-[RhCl(dCdCHFc)(PiPr3)2] (4).
Treatment of 4 with Grignard reagents RMgX affords the phenyl- and vinylrhodium(I)
derivatives trans-[Rh(R)(dCdCHFc)(PiPr3)2] (5, 6) of which the latter (R ) CHdCH2)
rearranges to the isomeric η3-2-4-butadienyl complex [Rh(η3-trans-CH2CHCdCHFc)(PiPr3)2]
(8). The corresponding η3-allyl compound [Rh(η3-anti-CH2CHdCHFc)(PiPr3)2] (7) is obtained
from 4 and CH3MgI, possibly via trans-[Rh(CH3)(dCdCHFc)(PiPr3)2] as an intermediate.
The X-ray crystal structure analysis of 7 confirms the anti position of the ferrocenyl group
at the allylic ligand.
In tr od u ction
In this paper we report the preparation of the alkynyl
and vinylidene complexes of composition [RhH(CtCFc)-
Cl(PiPr3)2] and trans-[RhCl(dCdCHFc)(PiPr3)2] with Fc
) (η5-C5H4-)Fe(η5-C5H5), the nucleophilic substitution
of the chloro ligand of the vinylidene compound by
phenyl and vinyl groups, and the conversion of the
postulated, in situ generated species trans-[Rh(CH3)-
(dCdCHFc)(PiPr3)2] and of the isolated analogue trans-
[Rh(CHdCH2)(dCdCHFc)(PiPr3)2] to the isomeric η3-
allyl and η3-butadienyl derivatives.
We have previously shown that in the coordination
sphere of rhodium(I) terminal alkynes HCtCR can be
easily converted to the isomeric vinylidenes.2,3 By using
[RhCl(PiPr3)2]2 (1) as the starting material, the reaction
with HCtCR occurs stepwise: the initially formed
π-alkyne complex trans-[RhCl(HCtCR)(PiPr3)2] affords
first the alkynyl(hydrido)rhodium(III) derivative [RhH-
(CtCR)Cl(PiPr3)2] which then rearranges to the final
product trans-[RhCl(dCdCHR)(PiPr3)2]. In the course
of our investigations we found that the stability of the
five-coordinate intermediate [RhH(CtCR)Cl(PiPr3)2]
significantly depends on the substituent R, compounds
with sterically demanding moieties such as tBu2c or
CMe2OH2e being more stable than those with H or
simple alkyl groups. The phenylethynyl complex [RhH-
(CtCPh)Cl(PiPr3)2] adopts an intermediary position:
under carefully controlled conditions it can be isolated
and spectroscopically characterized, but even at room
temperature it reacts quite rapidly to give the vinylidene
isomer.2b
Resu lts a n d Discu ssion
Reaction of the extremely air-sensitive chloro com-
pound 1 with 2 in pentane at 10 °C results in a clean
and quantitative formation of the alkynyl(hydrido)-
rhodium(III) complex 3 (Scheme 1). Even by monitoring
the process in C6D6 by 1H NMR spectroscopy, the
supposed intermediate trans-[RhCl(HCtCFc)(PiPr3)2]
could not be observed. The five-coordinate compound
3 is an orange solid which is soluble in most organic
solvents and decomposes at 105 °C. The most charac-
teristic features of the spectroscopic data are the CtC
stretching frequency of the alkynyl ligand at 2090 cm-1
in the IR spectrum and the high-field resonance of the
hydridic hydrogen at δ -27.98 in the 1H NMR spectrum.
The latter is split into a doublet of triplets due to Rh-H
and P-H coupling.
The isomerization of the alkynyl hydrido to the
vinylidene complex 4 occurs rather slowly in benzene
at room temperature and can be followed by a change
of color from orange to green. Upon recrystallization
from acetone, green, only moderately air-sensitive crys-
tals are isolated in virtually quantitative yield. The
generation of the vinylidene ligand is indicated by the
appearance of two doublets of triplets in the low field
region of the 13C NMR as well as by the signal of the
CdCHR proton at δ 0.90 in the 1H NMR spectrum.
Compound 4 is less soluble in common organic solvents
Since not for steric but for electronic reasons the
phenyl and ferrocenyl units are comparable, we decided
also to study the reactivity of ethynylferrocene 2 toward
1. We note that most recently Dixneuf et al. described
the synthesis of heterobimetallic Fe-Ni and Fe-Pd
oligomers which were obtained from a diynylferrocene
derivative as a precursor.4
† Dedicated to Professor Walter Siebert on the occasion of his 60th
birthday.
X Abstract published in Advance ACS Abstracts, February 1, 1997.
(1) Part 41 of the series Vinylidene Transition-Metal Complexes.
For part 40, see: Braun, T.; Meuer, P.; Werner, H. Organometallics
1996, 15, 4075-4077.
(2) (a) 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, 406-408. (b) Werner, H.; Garcia Alonso, F. J .; Otto, H.; Wolf, J . Z.
Naturforsch. B 1988, 43, 722-726. (c) Werner, H.; Brekau, U. Z.
Naturforsch. B 1989, 44, 1438-1446. (d) Werner, H.; Rappert, T.; Wolf,
J . Isr. J . Chem. 1990, 30, 377-384. (e) Werner, H.; Rappert, T. Chem.
Ber. 1993, 126, 669-678. (f) Werner, H.; Rappert, T.; Wiedemann, R.;
Wolf, J .; Mahr, N. Organometallics 1994, 13, 2721-2727.
(3) Short review: Werner, H. J . Organomet. Chem. 1994, 475, 45-
55.
(4) Lavastre, O.; Even, M.; Dixneuf, P. H.; Pacreau, A.; Vairon, J .-
P. Organometallics 1996, 15, 1530-1531.
S0276-7333(96)00825-4 CCC: $14.00 © 1997 American Chemical Society

Binuclear Iron-Rhodium Complexes
Organometallics, Vol. 16, No. 5, 1997 867
Sch em e 1a
an isomerization reaction leading to the η3-2-4-buta-
dienyl complex 8. The 1H NMR spectrum of the orange,
air-sensitive solid displays a rather complex pattern for
the protons H1-H4 (for exact assignment see Experi-
mental Section) which is due to Rh-H, P-H and H-H
couplings. The resonance of the syn proton H3 reveals
a considerably smaller H-H coupling with the central
proton H2 than that of the anti proton H4 which is in
agreement with previous findings.6,7 Since in the 13C
NMR spectrum of 8 a significant difference of the
chemical shift (ca. 120 ppm) for the signals of the carbon
atoms C2 and C4 is observed, we assume that the allylic
fragment of the butadienyl unit is unsymmetrically
coordinated to the metal center. This structural pro-
posal is supported by the 31P NMR spectrum of 8 which
displays two separate doublets of doublets with dis-
tinctly different Rh-P coupling constants.
The (η3-allyl)rhodium analogue of the η3-butadienyl
complex 8 has also been prepared although the expected
precursor trans-[Rh(CH3)(dCdCHFc)(PiPr3)2] could not
be isolated. Treatment of the chloro derivative 4 with
CH3MgI in benzene-ether at 5 °C leads to a smooth
change of color from green to orange and gives, after
removal of the solvent and recrystallization from ac-
a
L ) PiPr3.
Sch em e 2a
1
etone, orange crystals in 79% yield. Both the H and
13C NMR data indicate that the ferrocenyl-substituted
η3-allyl complex 7 has been obtained. With regard to
the mechanism of this reaction, we assume that initially
by nucleophilic substitution of the metal-bonded chloride
the four-coordinate intermediate trans-[Rh(CH3)(dCd
CHFc)(PiPr3)2] is generated which quickly rearranges
by migratory insertion of the vinylidene ligand into the
Rh-CH3 bond to give 7. It is conceivable that during
the rearrangement a η1-vinyl species [Rh{η1-C(CH3)d
CHFc}(PiPr3)2], analogous to [Rh(η1-CH2Ph)(PiPr3)2],7
is formed which by â-H shift reacts to give a four-
coordinate (η2-allene)hydridorhodium derivative.8 The
final product could then be formed by a hydride transfer
from the metal to the central carbon atom of the allene
unit. Support for the assumption that a vinyl ligand
such as C(CH3)dCHFc can rearrange to a 1-substituted
allyl group stems from previous work by Schwartz et
al., who found that the iridium compound trans-[Ir{Z-
C(CH3)dCHCH3}(CO)(PPh3)2] reacts on warming in
C6D6 to give the allyl isomer [Ir(η3-syn-1-CH3C3H4)(CO)-
(PPh3)2].9 A similar process involving a cationic vinyl-
rhodium(III) complex has been previously studied in our
laboratory.10
a
L ) PiPr3.
than the analogous derivatives trans-[RhCl(dCdCHR)-
(PiPr3)2] with R ) alkyl or aryl which we attribute to
the bulky and quite polar ferrocenyl group.
The chloro complex 4 reacts with phenyl and vinyl
Grignard reagents in benzene-ether or benzene-THF
to give the phenyl- and vinylrhodium(I) compounds 5
and 6 in 75-80% yield (Scheme 2). Since the IR and
the NMR data for the RhdCdCHFc unit of the starting
material 4 and the products 5 and 6 are quite similar,
we conclude that the attack of the nucleophile is
exclusively directed to the Rh-Cl and not to the Rh-C
bond. The 1H NMR spectrum of 6 displays three
distinct multiplets at δ 7.90, 6.30, and 5.27 for the vinyl
protons which in off-resonance appear as doublets of
doublets of doublets. As expected, the trans coupling
J (H1H2) is considerably larger than the cis coupling
J (H1H3) and both exceed by far the coupling between
the protons of the CH2 group. In the 31P NMR spectra
of 5 and 6 only one signal (doublet) with a similar
chemical shift as that of 4 is observed, and thus, there
is no doubt that the two phosphine ligands are trans
disposed.
The reason why the supposed intermediate trans-[Rh-
(CH3)(dCdCHFc)(PiPr3)2] is much more labile than the
structurally related species 5 and 6 is not quite clear.
The difference is also remarkable insofar as the analo-
gous compounds trans-[Rh(CH3)(dCdCHR)(PiPr3)2] with
R ) H, Ph, and tBu have been isolated and fully
(5) Wiedemann, R.; Steinert, P.; Scha¨fer, M.; Werner, H. J . Am.
Chem. Soc. 1993, 115, 9864-9865.
(6) Inter alia: (a) Reilly, C. A.; Thyret, H. J . Am. Chem. Soc. 1967,
89, 5144-5149. (b) Stu¨hler, H.-O.; Mu¨ller, J . Chem. Ber. 1979, 112,
1359-1364. (c) Sivak, A. J .; Muetterties, E. L. J . Am. Chem. Soc. 1979,
101, 4878-4887. (d) Fryzuk, M. D. Inorg. Chem. 1982, 21, 2134-2139.
(7) Werner, H.; Scha¨fer, M.; Nu¨rnberg, O.; Wolf, J . Chem. Ber. 1994,
127, 27-38.
(8) For the reverse process, the insertion of an allene into a Rh-H
bond, see: Osakada, K.; Choi, J .-C.; Koizumi, T.; Yamaguchi, I.;
Yamamoto, T. Organometallics 1995, 14, 4962-4965.
(9) Schwartz, J .; Hart, D. W.; McGiffert, B. J . Am. Chem. Soc. 1974,
96, 5613-5614.
Like the vinylrhodium(I) derivatives trans-[Rh(CHd
CH2)(dCdCHR)(PiPr3)2] (R ) Ph, tBu), which we
prepared quite recently,5 compound 6 also undergoes
(10) Wolf, J .; Werner, H. Organometallics 1987, 6, 1164-1169.

868 Organometallics, Vol. 16, No. 5, 1997
Wiedemann et al.
angle P1-Rh-P2 of 108.3(4)°is virtually the same as
in the η3-benzylrhodium(I) derivative [Rh(η3-CH2C6H4-
Me)(PiPr3)2] [108.8(1)°].7 This is noteworthy as in the
latter the Rh-P distances differ by 0.09 Å probably due
to the unsymmetrical coordination of the benzylic
ligand. The plane containing the carbon atoms C1, C2,
and C3 of compound 7 is not exactly perpendicular to
the P1,Rh,P2 plane. The orthogonal of the first best
plane intersects that of the latter at an angle of 77.8°.
Con clu sion
The present investigations have shown that a re-
markable difference exists in the reactivity of phenyl-
acetylene HCtCPh and ethynylferrocene (2) toward
[RhCl(PiPr3)2]2 (1). While on treatment with 1 the
former yields a stable π-alkyne complex with the [RhCl-
(PiPr3)2] unit, the corresponding compound with 2 as
ligand is extremely labile and quickly rearranges to the
alkynyl(hydrido)rhodium(III) isomer 3. This species as
well as the short-lived analogue [RhH(CtCPh)Cl-
(PiPr3)2] are readily converted to the vinylidene com-
plexes 4 and trans-[RhCl(dCdCHPh)(PiPr3)2] which
both undergo substitution reactions with methyl, vinyl,
and phenyl Grignard reagents to give the σ-bonded
derivatives trans-[Rh(R)(dCdCHFc)(PiPr3)2] and trans-
[Rh(R)(dCdCHPh)(PiPr3)2], respectively. For R ) CH3,
the kinetic stability of the two related vinylidenerho-
dium(I) compounds is strikingly different. Whereas the
complex with CdCHPh as ligand can be isolated and
stored at room temperature for some time,5 the coun-
terpart with Fc instead of Ph as substituent reacts
instantaneously to afford the π-allyl complex 7. The
remarkable feature is that in 7 the ferrocenyl unit
occupies the anti position at the allyl unit and thus
behaves analogously to the tert-butyl group. From this
we conclude that the steric and not the electronic effects
of the Fc moiety mainly determine the course of the
rearrangement of the supposed intermediate trans-[Rh-
(CH3)(dCdCHFc)(PiPr3)2] to give 7.
The C-C coupling which occurs during the formation
of 7 is not limited to methyl and vinylidene but also
takes place between vinyl and vinylidene, in this case
generating an η-2-4-butadienyl ligand. It should be
emphasized that this C-C coupling process does not
need the support of a Lewis base like CO5 or acetoni-
trile13 and occurs despite the fact that in the square-
planar precursors the methyl or vinyl and the vinylidene
ligands are trans to each other. We finally note that
the formation of an η-2-4-butadienyl unit by a metal-
assisted C-C coupling is not restricted to rhodium and
has recently also been observed in C5H5Ru chemistry.1
F igu r e 1. Solid state structure of 7, with anisotropic
uncertainty parameters depicting 50% probability. Hydro-
gen atoms other than those bonded to the allyl moiety have
been omitted for clarity.
Ta ble 1. Selected Bon d Dista n ces a n d An gles w ith
Esd ’s for Com p ou n d 7
Bond Distances (Å)
Rh-C1
Rh-C2
Rh-C3
Rh-P1
Rh-P2
C1-C2
C2-C3
2.254(4)
2.114(4)
2.198(4)
2.306(1)
2.304(1)
1.412(6)
1.403(6)
C1-C71
Fe-C71
Fe-C72
Fe-C73
Fe-C74
Fe-C75
1.467(6)
2.086(4)
2.050(4)
2.041(4)
2.037(4)
2.040(4)
Bond Angles (deg)
P1-Rh-P2
C1-Rh-C2
C1-Rh-C3
C2-Rh-C3
Rh-C1-C2
Rh-C2-C1
108.3(4)
37.6(2)
67.5(2)
37.9(2)
65.9(2)
76.6(2)
Rh-C2-C3
Rh-C3-C2
C1-C2-C3
Rh-C1-C71
C2-C1-C71
74.3(2)
67.8(2)
123.0(4)
113.4(2)
127.9(4)
characterized by IR and NMR spectroscopy.5 They
isomerize in benzene at room temperature rather slowly
(in ca. 12 h) to afford the η3-allyl complexes [Rh(η3-CH2-
CHCHR)(PiPr3)2] of which that with R ) Ph is formed
in the syn and that with R ) tBu in the anti configu-
ration.11 The metal-mediated C-C coupling of a methyl
and a vinylidene ligand to give an allylic unit is not
limited to rhodium and has recently also been observed
in ruthenium chemistry.1
To confirm the stereochemical arrangement of com-
plex 7, an X-ray diffraction study was carried out. As
shown in Figure 1, the substituted allylic ligand is η3
bonded with the ferrocenyl unit in the anti position. The
most notable feature is that the bond lengths between
the metal and the terminal carbon atoms of the C3
moiety are unequal and differ by ca. 0.06 Å. In spite of
the slightly unsymmetrical coordination of the allylic
ligand, the two Rh-P distances as well as the C1-C2
and the C2-C3 bond lengths are equal within their
estimated standard deviations (Table 1). The C1-C71
distance of the terminal allylic carbon atom to the five-
membered ring of the ferrocenyl fragment is 1.467(6) Å
and thus nearly the same as in a Fc-substituted al-
lylpalladium(II) complex in which the sandwich-type
unit is bonded to the central carbon atom.12 The bite
Exp er im en ta l Section
All reactions were carried out under an atmosphere of argon
by use of Schlenk techniques. The starting materials [RhCl-
(PiPr3)2]2 (1)14 and [(η5-C5H5)Fe(η5-C5H4CtCH)] (2)15 were
prepared as described in the literature. NMR spectra were
recorded at room temperature on Bruker AC 200 and Bruker
AMX 400 instruments, IR spectra on a Perkin-Elmer 1420
(13) Fryzuk, M. D.; Huang, L; McManus, N. T.; Paglia, P.; Rettig,
S. J .; White, G. S. Organometallics 1992, 11, 2979-2990.
(14) Werner, H.; Wolf, J .; Ho¨hn, A. J . Organomet. Chem. 1985, 287,
395-407.
(15) Doisneau, G.; Balavoine, G.; Fillebeen-Kahn, T. J . Organomet.
Chem. 1992, 425, 113-117.
(11) Wiedemann, R.; Wolf, J .; Werner, H. Angew. Chem. 1995, 107,
1359-1361; Angew. Chem., Int. Ed. Engl. 1995, 34, 1244-1246.
(12) Wu, Y. J .; Liu, Y. H.; Yuan, H. Z.; Mao, X. A. J . Organomet.
Chem. 1996, 519, 237-242.

Binuclear Iron-Rhodium Complexes
Organometallics, Vol. 16, No. 5, 1997 869
infrared spectrometer, and mass spectra on a Finnigan 90
MAT instrument. Melting points were determined by DTA.
P r ep a r a t ion of [R h H {(CtC-η5-C5H 4)F e(η5-C5H 5)}Cl-
(P iP r 3)2] (3). A solution of 1 (260 mg, 0.28 mmol) in 5 mL of
pentane was treated at 10 °C with 2 (120 mg, 0.57 mmol)
which led to a change of color from red-violet to yellow. After
the solution was stirred for 5 min, orange crystals began to
precipitate. The solution was stored for 1 h at -78 °C, and
the precipitate was separated from the mother liquor, washed
three times with 3-mL portions of pentane (-20 °C), and
dried: yield 349 mg (92%); mp 105 °C dec; IR (C6H6) ν(CtC)
covered by signal of PCHCH3; 13C NMR (C6D6, 50.3 MHz) δ
301.0 [dt, J (RhC) ) 47.0, J (PC) ) 17.2 Hz, RhdCdCHR], 175.0
[dt, J (RhC) ) 26.1, J (PC) ) 14.0 Hz, Rh-CHdCH2], 120.4 [t,
J (PC) ) 3.8 Hz, Rh-CHdCH2], 110.6 [dt, J (RhC) ) 10.8, J (PC)
) 5.4 Hz, RhdCdCHR], 73.7 [t, J (PC) ) 2.5 Hz, i-C5H4R], 68.9
(s, C5H5), 67.1, 65.6 (both s, C5H4R), 25.5 [dvt, J (RhC) ) 1.3,
N ) 19.7 Hz, PCHCH3], 20.5 (s, PCHCH3); 31P NMR (C6D6,
81.0 MHz) δ 44.1 [d, J (RhP) ) 145.6 Hz]. Anal. Calcd for
C
32H55FeP2Rh: C, 58.19; H, 8.39. Found: C, 58.43; H, 8.45.
1
2090 cm-1; H NMR (C6D6, 200 MHz) δ 4.25 (m, 2H, C5H4R),
4.17 (s, 5H, C5H5), 3.98 (m, 2H, C5H4R), 2.87 (m, 6H, PCHCH3),
1.33 [dvt, N ) 13.1, J (HH) ) 7.3 Hz, 18H, PCHCH3], 1.30 [dvt,
N ) 13.1, J (HH) ) 7.2 Hz, 18H, PCHCH3], -27.98 [dt, J (RhH)
) 39.6, J (PH) ) 17.1 Hz, 1H, RhH]; 31P NMR (C6D6, 81.0 MHz)
δ 50.2 [d, J (RhP) ) 99.0 Hz]. Anal. Calcd for C30H52ClFeP2-
Rh: C, 53.87; H, 7.84. Found: C, 53.54; H, 7.89.
P r ep a r a tion of [Rh {(η3-a n ti-CH2CHCH-η5-C5H4)F e(η5-
C5H5)}(P iP r 3)2] (7). A solution of 4 (134 mg, 0.20 mmol) in 5
mL of benzene was treated at 5 °C with 0.4 mL of a 1.0 M
solution of CH3MgI in ether and then stirred for 3 h at room
temperature. A smooth change of color from green to orange
occurred. The solvent was removed, the residue was extracted
with 15 mL of pentane, and the extract was brought to dryness
in vacuo. The residue was dissolved in 10 mL of acetone, and
the solution was stored for 2 d at -78 °C. Orange crystals
precipitated, which were separated from the mother liquor,
washed three times with 2 mL portions of acetone (-20 °C),
and dried: yield 103 mg (79%); mp 92 °C dec; 1H NMR (C6D6,
400 MHz) (assignments shown below) δ 4.98 [m, in 1H{31P}
dddd, J (RhH2) ) 1.7, J (H2H4) ) 12.1, J (H1H2) ) 7.9, J (H2H3)
) 7.8 Hz, 1H, H2], 4.46 [m, in 1H{31P} d, J (H1H2) ) 7.9 Hz,
1H, H1], 4.18 (s, 5H, C5H5), 4.15, 3.99, 3.91 (all m, 4H, CH of
P r ep a r a tion of tr a n s-[Rh Cl{(dCdCH-η5-C5H4)F e(η5-
C5H5)}(P iP r 3)2] (4). A solution of 3 (230 mg, 0.34 mmol) in 5
mL of benzene was stirred for 10 h at room temperature. A
smooth change of color from orange to green occurred. The
solvent was removed in vacuo, the residue was dissolved in
15 mL of acetone, and the solution was stored for 24 h at -78
°C. Green crystals precipitated which were separated from
the mother liquor, washed three times with 3 mL portions of
acetone (-20 °C), and dried: yield 221 mg (96%); mp 143 °C;
IR (C6H6) ν(CdC) 1620 cm-1; 1H NMR (C6D6, 200 MHz) δ 3.99
(s, 5H, C5H5), 3.94 (m, 4H, C5H4R), 2.75 (m, 6H, PCHCH3),
1.31 [dvt, N ) 13.5, J (HH) ) 6.9 Hz, 36H, PCHCH3], 0.90 [dt,
J (RhH) ) 0.7, J (PH) ) 3.3 Hz, 1H, RhdCdCHR]; 13C NMR
(C6D6, 50.3 MHz) δ 294.4 [dt, J (RhC) ) 59.1, J (PC) ) 16.5
Hz, RhdCdCHR], 104.6 [dt, J (RhC) ) 15.9, J (PC) ) 6.4 Hz,
RhdCdCHR], 70.9 [t, J (PC) ) 2.2 Hz, i-C5H4R], 69.0 (s, C5H5),
67.5, 66.3 (both s, C5H4R), 23.7 [dvt, J (RhC) ) 1.3, N ) 20.0
Hz, PCHCH3], 20.4 (s, PCHCH3); 31P NMR (C6D6, 81.0 MHz)
δ 43.3 [d, J (RhP) ) 134.6 Hz]; MS (70 eV) m/z 668 (M+), 458
[RhCl(PiPr3)2+], 210 (2+). Anal. Calcd for C30H52ClFeP2Rh
(668.9): C, 53.87; H, 7.84. Found: C, 53.57; H, 7.60.
1
C5H4R), 2.86 [m, in H{31P} d, J (H2H3) ) 7.8 Hz, 1H, H3), 2.45
(dd, br, J (P2H4) ) 7.2, J (H2H4) ) 12.1 Hz, 1H, H4), 2.21, 2.13
(both m, 3H each, PCHCH3), 1.25 [dd, J (PH) ) 12.8, J (HH) )
7.2 Hz, 9H, PCHCH3], 1.21 [dd, J (PH) ) 11.6, J (HH) ) 7.2
Hz, 9H, PCHCH3], 1.14 [dd, J (PH) ) 11.2, J (HH) ) 7.2 Hz,
9H, PCHCH3], 1.05 [dd, J (PH) ) 12.4, J (HH) ) 7.2 Hz, 9H,
PCHCH3]; 13C NMR (C6D6, 100.6 MHz) δ 94.2 [d, J (PC) ) 5.7
Hz, i-C5H4R)], 90.8 (m, C2), 70.0, 67.9, 67.8, 65.8 (all s, C5H4R),
69.7 (s, C5H5), 61.4 [ddd, J (RhC) ) 22.9, J (P1C) ) 8.0, J (P2C)
) 4.1 Hz, C1], 45.1 [ddd, J (RhC) ) 28.5, J (P2C) ) 8.2, J (P1C)
) 5.5 Hz, C3], 28.7 [d, br, J (PC) ) 14.4 Hz, PCHCH3], 28.6 [d,
br, J (PC) ) 13.2 Hz, PCHCH3], 21.4, 21.2 [both d, J (PC) )
3.2 Hz, PCHCH3], 20.5, 20.4 (both s, PCHCH3); 31P NMR (C6D6,
162.0 MHz) δ 55.4 [dd, J (RhP) ) 191.8, J (PP) ) 20.2 Hz, P1],
47.9 [dd, J (RhP) ) 191.0, J (PP) ) 20.2 Hz, P2]. Anal. Calcd
for C31H55FeP2Rh: C, 57.42; H, 8.55. Found: C, 56.97; H, 8.49.
P r ep a r a tion of tr a n s-[Rh (C6H5){(dCdCH-η5-C5H4)F e-
(η5-C5H5)}(P iP r 3)2] (5). A solution of 4 (175 mg, 0.26 mmol)
in 3 mL of benzene was treated at 10 °C with 0.5 mL of a 1.0
M solution of C6H5MgBr in ether. After the reaction mixture
was stirred for 2 h at room temperature, the solvent was
removed in vacuo, and the residue was extracted with 30 mL
of pentane. The extract was filtered, and the filtrate was
concentrated to about 3 mL in vacuo and then stored for 15 h
at -78 °C. Dark green crystals precipitated which were
separated from the mother liquor, washed three times with 2
mL portions of acetone (-20 °C), and dried: yield 138 mg
1
(74%); mp 67 °C dec; IR (C6H6) ν(CdC) 1605 cm-1; H NMR
(C6D6, 200 MHz) δ 7.93 (m, 2H, o-C6H5), 7.43 (m, 2H, m-C6H5),
6.98 (m, 1H, p-C6H5), 4.09 (s, 5H, C5H5), 4.08, 4.00 (both m,
2H each, C5H4R), 2.35 (m, 6H, PCHCH3), 1.57 [t, J (PH) ) 4.2
Hz, 1H, RhdCdCHR], 1.21 [dvt, N ) 13.2, J (HH) ) 6.9 Hz,
36H, PCHCH3]; 31P NMR (C6D6, 81.0 MHz) δ 40.9 [d, J (RhP)
) 145.8 Hz]. Anal. Calcd for C36H57FeP2Rh: C, 60.85; H, 8.09.
Found: C, 60.28; H, 7.80.
P r ep a r a t ion of [R h {(η3-tr a n s-CH2CHCdCH-η5-C5H4)-
F e(η5-C5H5)}(P iP r 3)2] (8). A solution of 6 (110 mg, 0.17
mmol) in 3 mL of benzene was stirred for 1 h at 50 °C which
led to a change of color from green to orange. Upon cooling of
the solution to room temperature, the solvent was removed,
the residue was dissolved in 3 mL of acetone, and the solution
was stored for 10 h at -78 °C. Orange crystals were formed
which were isolated as described for 7: yield 89 mg (81%); mp
99 °C dec; 1H NMR (C6D6, 400 MHz) (assignments shown
below) δ 5.93 [dd, J (P1H) ) 5.1, J (H1H2) ) 2.1 Hz, 1H, H1],
4.70, 4.62 (both m, 1H each, C5H4R), 4.59 (m, 1H, H2), 4.14 (s,
P r ep a r a tion of tr a n s-[Rh (CHdCH2){(dCdCH-η5-C5H4)-
F e(η5-C5H5)}(P iP r 3)2] (6). This was prepared as described
for 5, from 4 (220 mg, 0.33 mmol) and 0.50 mL of a 1.0 M
solution of CH2dCHMgBr in THF. Upon recrystallization
from pentane (-78 °C) a violet microcrystalline solid was
obtained: yield 172 mg (79%); mp 91 °C dec; IR (C6H6) ν(CdC)
1610 cm-1 1H NMR (C6D6, 200 MHz) (assignments shown
;
below) δ 7.90 [m, in 1H{31P} ddd, J (RhH1) ) 1.1, J (H1H2) )
19.8, J (H1H3) ) 14.2 Hz, 1H, H1], 6.30 [m, in 1H{31P} ddd,
J (RhH3) ) 2.9, J (H1H3) ) 14.2, J (H2H3) ) 4.2 Hz, 1H, H3],
5.27 [m, in 1H{31P} ddd, J (RhH2) ) 1.4, J (H1H2) ) 19.8,
J (H2H3) ) 4.2 Hz, 1H, H2], 4.07 (s, 5H, C5H5), 4.03, 3.99 (both
m, 2H each, C5H4R), 2.63 (m, 6H, PCHCH3), 1.27 [dvt, N )
13.1, J (HH) ) 7.0 Hz, 36H, PCHCH3]; signal of dCHR partly
1
5H, C5H5), 4.13 (m, 2H, C5H4R), 3.19 [m, in H{31P} d, J (H2H3)
) 7.4 Hz, 1H, H3], 2.37, 2.15 (both m, 3H each, PCHCH3), 2.21
[dd, J (P2H4) ) 6.2, J (H2H4) ) 12.1 Hz, 1H, H4], 1.30 [dd, J (PH)
) 13.0, J (HH) ) 7.2 Hz, 9H, PCHCH3], 1.25 [dd, J (PH) ) 12.1,
J (HH) ) 7.3 Hz, 9H, PCHCH3], 1.17 [dd, J (PH) ) 12.6, J (HH)
) 7.2 Hz, 9H, PCHCH3], 1.13 [dd, J (PH) ) 12.1, J (HH) ) 7.2

870 Organometallics, Vol. 16, No. 5, 1997
Wiedemann et al.
2
Hz, 9H, PCHCH3]; 13C NMR (C6D6, 100.6 MHz) δ 168.7 [ddd,
J (RhC) ) 39.2, J (P1C) ) 19.1, J (P2C) ) 9.1 Hz, C2], 107.5 (s,
C1), 88.8 [d, J (PC) ) 7.0 Hz, i-C5H4R], 79.1 [d, J (RhC) ) 3.6
Hz, C3], 69.2, 68.0, 66.8, 66.7 (all s, C5H5 and C5H4R), 49.2
[ddd, J (RhC) ) 24.1, J (P2C) ) 6.2, J (P1C) ) 5.9 Hz, C4], 28.4
[d, J (PC) ) 12.2 Hz, PCHCH3], 27.7 [d, J (PC) ) 14.9 Hz,
PCHCH3], 21.4 [d, J (PC) ) 2.9 Hz, PCHCH3], 20.8 [d, J (PC)
) 3.0 Hz, PCHCH3], 20.7, 20.5 (both s, PCHCH3); 31P NMR
(C6D6, 162.0 MHz) δ 53.8 [dd, J (RhP) ) 198.3, J (PP) ) 21.7
Hz, P2], 47.3 [dd, J (RhP) ) 160.5, J (PP) ) 21.7 Hz, P1]. Anal.
Calcd for C32H55FeP2Rh: C, 58.19; H, 8.39. Found: C, 57.88;
H, 7.93.
|Fc||/∑|Fo| and wR2 ) (∑w(Fo - Fc2)2/∑w(Fo2)2)0.5
. The data
set was collected on a Stoe-Huber-Siemens diffractometer
fitted with a Siemens CCD detector system at 153(2) K using
Mo KR radiation (λ ) 0.710 73 pm). Semiempirical absorption
correction was applied. The structure was solved by direct
methods.17 All non-hydrogen atoms were refined anisotropi-
cally, and a riding model was employed in the refinement of
the hydrogen atom positions, except for those who are bonded
to the C1-C3 allylic moiety, which were refined freely. The
structure was refined against F2 with a weighting scheme w-1
) σ2(Fo2) + (g1P)2 + g2P, where P ) (Fo + 2Fc2)/3.18
2
Ack n ow led gm en t. We thank the Deutsche Fors-
chungsgemeinschaft (Grant SFB 347), the Volkswagen-
Stiftung, and the Fonds der Chemischen Industrie for
financial support. We also gratefully acknowledge
support by Mrs. I. Geiter (technical assistance), Mrs.
R. Schedl and Mr. C. P. Kneis (elemental analysis and
DTA), Mrs. M. L. Scha¨fer and Dr. W. Buchner (NMR
measurements), Dr. G. Lange and Mr. F. Dadrich (mass
spectra), and Degussa AG (chemicals).
X-r a y Mea su r em en ts of 7. Single crystals were grown
from acetone at -20 °C. Crystal data for 7: C31H55FeP2Rh,
M ) 648.45, monoclinic, space group P21/n, a ) 9.895(1) Å, b
) 15.081(3) Å, c ) 21.683(3) Å, â ) 103.09(2)°, V ) 3151.6(8)
Su p p or tin g In for m a tion Ava ila ble: An ORTEP diagram
and tables of data collection parameters, bond lengths and
angles, positional and thermal parameters, and least-squares
planes for 7 (8 pages). Ordering information is given on any
current masthead page.
Å3, Z ) 4, Dc ) 1.367 Mg m-3, µ (Mo KR) ) 1.103 mm-1
.
Intensities of a 0.5 × 0.5 × 0.5 mm rapidly cooled crystal in
an oil drop16 were collected by the æ-scan method to 2θmax
)
50°. Of a total of 5581 scanned reflections 5580 were inde-
pendent and used to refine 341 parameters, with a largest
difference peak and hole of 1.11 and -0.60 e Å-3
. R1 (F >
OM960825A
4σ(F)) ) 0.046 and wR2 ) 0.094 (all data) with R1 ) ∑||Fo| -
(17) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467.
(18) Sheldrick, G. M. SHELXL-96, program for crystal structure
refinement, Go¨ttingen, 1996.
(16) (a) Kottke, T.; Stalke, D. J . Appl. Crystallogr. 1993, 26, 615.
(b) Kottke, T.; Lagow, R. J .; Stalke, D. J . Appl. Crystallogr., in press.