Acetylacetonato, pentachlorophenolato and carboxylato rhodium(I) complexes and their reactivity in the C-C coupling reaction of olefins and diazoalkanes

Article abstract of DOI:10.1016/j.poly.2004.06.009

This work extends the series of chelate rhodium(I) complexes with Rh(PiPr₃)₂ as the core unit.The complexes not only react with ethene but also with diazoalkanes. The acetylacetonato complexes [Rh(κ²-O-O)(C₂H₄)(PiPr₃)] (O-O = acac 5, acac-f₃ 6, acac-f₆ 7) and [Rh(κ ²-O-O)(PiPr₃)₂] (O-O = acac 10, acac-f ₆ 11) were prepared from either [Rh(κ²-O-O)(C ₂H₄)₂] (2-4), [Rh(η³-C ₃H₅)(PiPr₃)₂] (8) or [RhCl(PiPr ₃)₂]₂ (9) as the starting materials.While attempts to obtain the diazoalkane derivatives [Rh(κ²-O-O) (N₂CR₂)(PiPr₃)] (R Ph, p-Tol) failed, treatment of 5-7 with N₂CC₄Cl₄ gave the corresponding substitution products [Rh(κ²-O-O)(N₂CC ₄Cl₄)(PiPr₃)] (12-14) in good yields.The reaction of 8 with C₆Cl₅OH afforded the square-planar complex [Rh(κ²-OC₆Cl₅)(PiPr ₃)₂] (15), in which the pentachlorophenolato ligand is coordinated in a chelating fashion.From 15 and C₂H₄, O₂ and N₂CPh₂ the 1:1 adducts trans-[Rh(κ¹-OC₆Cl₅)(L)(PiPr ₃)₂] (16-18) were prepared.Compound 15 catalyzes the reaction of ethene with diaryldiazomethanes to give, instead of 1,1-diarylcyclopropanes, the isomeric olefins R₂CCHCH₃ (R = C₆H₅ 1b, p-C₆H₄Me 19, p-C ₆H₄Cl 20) as the main products.The carboxylato complexes [Rh(κ²-O₂CMe)(PiPr₃)₂] (21) and [Rh(κ²-O₂CCF₃)(PiPr₃) ₂] (25) react with N₂CRR′ (R = R′ = C ₄Cl₄; R = R′ = Ph; R = H, Ph, R′ = C(O)Ph) by opening the chelate bond to give the four-coordinate 1:1 adductstrans- [Rh(κ¹-O₂CMe)(N₂CRR′)(PiPr ₃)₂] (22-24) and trans-[Rh(κ¹-O ₂CCF₃)(N₂CRR′)(PiPr₃) ₂] (26-28), respectively. Treatment of 25 with PhCHN₂ produced the dinitrogen complex trans-[Rh(κ¹-O ₂CCF₃)(N₂)(PiPr₃)₂] (29). In contrast to the trifluoracetato compound 25, which catalyzes the reaction of ethene and diaryldiazomethanes N₂CRR′ to give mainly the trisubstituted olefins R′RCCHCH₃, the corresponding reaction of C₂H₄ and N₂CRR′ with acetato complex 21 as the catalyst affords the isomeric ethene derivatives CH ₂CHCHRR′ as the major products. A mechanism for this unexpected C-C coupling reaction is discussed.

Full text of DOI:10.1016/j.poly.2004.06.009

Polyhedron 23 (2004) 2645–2657
www.elsevier.com/locate/poly
Acetylacetonato, pentachlorophenolato and carboxylato
rhodium(I) complexes and their reactivity in the C–C
coupling reaction of olefins and diazoalkanes
*
Helmut Werner , Norbert Mahr, Michael E. Schneider, Marco Bosch, Justin Wolf
Institut fu¨r Anorganische Chemie, Universita¨t Wu¨rzburg, Am Hubland, D-97074 Wu¨rzburg, Germany
Received 8 April 2004; accepted 8 June 2004
Available online 30 July 2004
Dedicated to Professor Malcolm Green, in honour of his numerous inspiring contributions to Organometallic Chemistry
Abstract
The acetylacetonato complexes [Rh(j2-O-O)(C2H4)(PiPr3)] (O-O=acac 5, acac-f3 6, acac-f6 7) and [Rh(j2-O-O)(PiPr3)2]
(O-O=acac 10, acac-f6 11) were prepared from either [Rh(j2-O-O)(C2H4)2] (2–4), [Rh(g3-C3H5)(PiPr3)2] (8) or [RhCl(PiPr3)2]2
(9) as the starting materials. While attempts to obtain the diazoalkane derivatives [Rh(j2-O-O)(N2CR2)(PiPr3)] (R‚Ph, p-Tol)
failed, treatment of 5–7 with N2CC4Cl4 gave the corresponding substitution products [Rh(j2-O-O)(N2CC4Cl4)(PiPr3)] (12–14) in
good yields. The reaction of 8 with C6Cl5OH afforded the square-planar complex [Rh(j2-OC6Cl5)(PiPr3)2] (15), in which the pen-
tachlorophenolato ligand is coordinated in a chelating fashion. From 15 and C2H4, O2 and N2CPh2 the 1:1 adducts trans-[Rh(j1-
OC6Cl5)(L)(PiPr3)2] (16–18) were prepared. Compound 15 catalyzes the reaction of ethene with diaryldiazomethanes to give, instead
of 1,1-diarylcyclopropanes, the isomeric olefins R2C‚CHCH3 (R=C6H5 1b, p-C6H4Me 19, p-C6H4Cl 20) as the main products. The
carboxylato complexes [Rh(j2-O2CMe)(PiPr3)2] (21) and [Rh(j2-O2CCF3)(PiPr3)2] (25) react with N2CRR0 (R=R0 =C4Cl4;
R=R0 =Ph; R=H, Ph, R0 =C(O)Ph) by opening the chelate bond to give the four-coordinate 1:1 adducts trans-[Rh(j1-
O2CMe)(N2CRR0)(PiPr3)2] (22–24) and trans-[Rh(j1-O2CCF3)(N2CRR0)(PiPr3)2](26–28), respectively. Treatment of 25 with
PhCHN2 produced the dinitrogen complex trans-[Rh(j1-O2CCF3)(N2)(PiPr3)2] (29). In contrast to the trifluoracetato compound
25, which catalyzes the reaction of ethene and diaryldiazomethanes N2CRR0 to give mainly the trisubstituted olefins
R0RC‚CHCH3, the corresponding reaction of C2H4 and N2CRR0 with acetato complex 21 as the catalyst affords the isomeric
ethene derivatives CH2‚CHCHRR0 as the major products. A mechanism for this unexpected C–C coupling reaction is discussed.
ꢀ 2004 Elsevier Ltd. All rights reserved.
Keywords: Rhodium; Acetylacetonato complexes; Pentachlorophenolato complexes; Carboxylato complexes; Diazoalkane complexes; C–C coupling
reactions
1. Introduction
composition trans-[RhCl(‚CRR0)(L)2] with L=PR3,
AsR3 and SbR3 [1], we observed that upon treatment
In the context of our studies on the preparation and re-
activity of carbenerhodium(I) complexes of the general
of
[RhCl(C2H4)2]2,
[Rh(j2-acac-f6)(C2H4)2]
or
[RhCl- (PiPr3)2]2 with an excess of ethene and diphenyldi-
azomethane a catalytic reaction occurred and the trisub-
stituted olefin 1,1-diphenylpropene (1b) was generated as
the dominating product [2,3]. The formation of this olefin
can be considered, in a formal sense, as the coupling of
two carbene fragments :CPh2 and :CHMe, of which the
*
Corresponding
+499318884623.
author.
Tel.:
+499318885270;
fax:
E-mail address: helmut.werner@mail.uni-wuerzburg.de (H. Wer-
ner).
0277-5387/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2004.06.009

2646
H. Werner et al. / Polyhedron 23 (2004) 2645–2657
H
CH3
Ph
[Kat1]
- N2
Ph2CN2
[Kat2]
- N2
Ph
+
H2C
CH2
Ph
Ph
1a
1b
[Kat1] : [Rh2(O2CCH3)4], [Rh6(CO)16], [Rh(κ2-acac)(C2H4)2]
[Kat2] : [RhCl(C2H4)2]2, [RhCl(PiPr3)2]2, [Rh(κ2-acac-f6)(C2H4)2]
Scheme 1.
R
latter derives from the isomeric ethene. Besides 1b, only
traces of the isomeric disubstituted cyclopropane 1a
could be detected which was surprising insofar as it was
well known that dinuclear bis(carboxylato)rhodium(II)
compounds such as [Rh2(O2CMe)4] and derivatives
thereof [4], some carbonylrhodium(0) clusters [5] and
the chelated rhodium(I) complex [Rh(j2-acac)(C2H4)2]
[6] are effective catalysts for the synthesis of cyclopro-
panes from olefins and diazoalkanes (Scheme 1).
R
O
O
O
PiPr3
+ PiPr3
Rh
Rh
- C2H4
O
R'
R'
5-7
2-4
+ 2 PiPr3
- 2 C2H4
By taking the difference in reactivity of [Rh(j2-
acac)(C2H4)2] on one hand and of [RhCl(C2H4)2]2 and
[Rh(j2-acac-f6)(C2H4)2] on the other into consideration,
it became quite obvious that the anionic ligand of the
corresponding rhodium complex has a significant influ-
ence on the course of the reaction of ethene and diphe-
nyldiazomethane. Therefore, we set out to prepare some
relatives of the above-mentioned chelated rhodium(I)
compounds and to study their reactivity, in particular
the directing role of the ligands in the C–C coupling re-
action. For comparison, we also included in our investi-
gations the mononuclear carboxylato derivatives
[Rh(j2-O2CR)(PiPr3)2] (R=CH3, CF3, p-C6H4OMe, p-
C6H4NO2), the preparation of which was recently re-
ported by our group [7]. Some preliminary results of
the present work have already been communicated [8].
R
O
PiPr3
PiPr3
PiPr3
PiPr3
+ f6-acacH
- C3H6
Rh
Rh
O
R'
8
+ Na(acac)
10,11
- NaCl
1/2 [RhCl(PiPr3)2]2
R
R'
CH3 CH3
CH3 CF3
2, 5, 10
3, 6
4, 7, 11 CF3 CF3
9
Scheme 2.
19F NMR:
δ -74.3
19F NMR:
δ -74.5
31P NMR:
δ 61.7
F3C
F3C
2. Results and discussion
O
O
O
O
PiPr3
1H NMR:
H
1H NMR:
δ 5.70
Rh
Rh
H
The synthetic routes leading to the mono(phosphine)
and bis(phosphine) acetylacetonato complexes 5–7 and
10, 11 are outlined in Scheme 2. The preparation of 5
and 7 by ligand exchange from 2 and 4 with an equimo-
lar amount of PiPr3 has previously been described and
the spectroscopic data have been reported [9]. Com-
pound 6 with acac-f3 as an unsymmetrical chelating lig-
and, was isolated as a mixture of two isomers showing
slightly different NMR signals (see Scheme 3). Since
the isomers are formed in a ratio of cis-6:trans-
6=15:1, the corresponding signals can be easily as-
signed. The bis(phosphine) compound 11 was initially
prepared from 4 and two equivalents of PiPr3 in a mod-
δ 5.65
PiPr3
δ 1.52
δ 1.54
H3C
H3C
31P NMR:
cis-6
trans-6
δ 61.3
Scheme 3.
est yield [9]. The preferred pathway is the reaction of 8
with hexafluoroacetylacetone, which gives 11 in 76%
yield by elimination of propene.
Quite surprisingly, the acac complex 10 is not acces-
sible either from 2 and excess PiPr3 or from 8 and
acacH. However, it can be obtained by salt metathesis

H. Werner et al. / Polyhedron 23 (2004) 2645–2657
2647
from 9 and Na(acac) in a slurry of diethylether. Both 10
Cl
Cl
and 11 are moderately air-sensitive solids, which are
readily soluble in aromatic and chlorinated solvents
but almost insoluble in pentane and diethylether. The
IR as well as the 1H and 13C NMR data of 10 are similar
to those of the bis(tricyclohexylphosphine) compound
[Rh(j2-acac)(PCy3)2], the molecular structure of which
was determined by X-ray crystallography [10].
While the ethene ligand in the chlororhodium(I) com-
plex trans-[RhCl(C2H4)(PiPr3)2] can be smoothly dis-
placed by diphenyldiazomethane [2], attempts to
substitute the olefin in compounds 5–7 by N2CPh2
failed. Although the formation of a 2:3 mixture of 1a
and 1b could be detected by GC–MS, the composition
of the organometallic product remained obscure.
However, the starting materials 5–7 react with
N2CC4Cl4 in pentane at low temperatures to afford the
diazocyclopentadiene complexes 12–14 in 58–79% yields
(Scheme 4). The greenish air-stable solids were charac-
terized by elemental analysis and mass spectra. Even if
they were stored in solution at 20 ꢁC for several days,
no conversion to a corresponding carbene derivative oc-
curred by elimination of N2. The IR spectra of 12–14
display the N–N stretching mode at around 1950
cmꢀ1, which is shifted by ca. 150 cmꢀ1 to lower frequen-
cy compared with uncoordinated N2CC4Cl4. Since the
signals for the N2C carbon atom appear in the 13C
NMR spectra of 12–14 at about the same chemical shift
as that of trans-[RhCl(N2CC4Cl4)(SbiPr3)2] (which was
characterized crystallographically) [11], we assume that
the N2CC4Cl4 ligands in 12–14 are bonded end-on to
the metal center. In the presence of ethene, compounds
12–14 are inert and even upon heating do not undergo
a C–C coupling reaction.
The preferred preparative route to obtain the penta-
chlorophenolato complex 15 is similar to that used for
the related compound 11. Treatment of 8 with an equi-
molar amount of C6Cl5OH in toluene gave 15 (Scheme 5)
as a red microcrystalline solid, which is exceedingly air-
sensitive and slowly decomposes in solution. The 1H
NMR spectrum of 15 shows at room temperature a sin-
gle resonance for the methyl protons of the isopropyl
groups indicating that under these conditions the two
Cl
Cl
Cl
O
PiPr3
PiPr3
PiPr3
PiPr3
C6Cl5OH
- C3H6
Rh
Rh
8
15
Scheme 5.
PiPr3 ligands are equivalent on the NMR timescale. Ac-
cordingly, the 31P NMR spectrum of 15 displays at 295
K one doublet at d 61.2, which at 213 K splits into two
doublets of doublets at d 60.4 and 59.2. On the basis of
these observations, we assume that at room temperature
compound 15 is fluxional in solution and that the two
identical chelates are transformed into each other via a
three-coordinate species as an intermediate (Scheme 6).
From the coalescence temperature (228 K in toluene-
d8) and the difference in the chemical shift of the two sig-
nals at 213 K in the 31P NMR spectrum, a DG„ value of
37 kJ/mol can be calculated. We note that the chelating
capability of the pentachlorophenolate anion is not un-
expected and has also been illustrated in gold(I) [12,13]
as well as in ruthenium(II) and osmium(II) chemistry
[14].
In agreement with the rather weak interaction be-
tween Rh and Cl, compound 15 reacts readily at room
temperature with ethene in pentane to give the non-che-
late complex 16 in good yield (Scheme 7). The olefinic
ligand is only weakly coordinated and thus, during at-
tempts to dry 16 in vacuo, the starting material 15 was
regenerated. Under argon at 295 K, or in solution at
223 K in the presence of excess ethene, 16 can be stored
without decomposition. The 31P NMR spectrum of 16 in
toluene-d8 shows at 223 K a doublet resonance with a
31P–103Rh coupling constant of 125.0 Hz, which is typi-
cal for a trans-disposed PiPr3–Rh–PiPr3 moiety [11,15].
More readily than with ethene, compound 15 reacts
with O2 in pentane to form the 1:1 adduct 17. The
brownish compound, the composition of which has been
substantiated by elemental analysis, is moderately air-
sensitive and decomposes slowly both in solution and
Cl
Cl
R'
R'
Cl
Cl
O
Cl
Cl
Cl
O
PiPr3
PiPr3
PiPr3
PiPr3
O
O
O
O
PiPr3
PiPr3
Rh
N2CC4Cl4
- C2H4
Rh
Cl
Cl
Rh
Rh
Cl
Cl
Cl
N
N
Cl
Cl
R
R
5-7
Cl
Cl
Cl
R
R'
12-14
PiPr3
PiPr3
CH3 CH3
CH3 CF3
14 CF3 CF3
12
13
Cl
O Rh
Cl
Scheme 4.
Scheme 6. Dynamics of compound 15 in solution.

2648
H. Werner et al. / Polyhedron 23 (2004) 2645–2657
1
PiPr3
the nitrogen atoms. The H NMR spectrum of 18 dis-
plays one doublet of virtual triplets for the PCHCH3
protons, which indicates that the two phosphine ligands
are in a trans disposition [15,17].
C6Cl5O Rh
PiPr3
16
Although the diazoalkane complex 18 reacts with a
saturated solution of ethene in benzene at 40 ꢁC rather
slowly to give the olefin 1b, the precursor 15 catalyzes
not only the reaction of C2H4 with N2CPh2 but also that
of ethene with N2C(C6H4Me-p)2 and N2C(C6H4Cl-p),
respectively (Scheme 9). By monitoring the correspond-
ing reactions by NMR, the exclusive formation of the
C–C coupling products 1b, 19 and 20 has been observed.
The turnover number (TON) is ca. 10 and thus is much
lower than with [RhCl(PiPr3)2]2 or [RhCl(C2H4)2]2 as
the catalyst [2,3].
To compare the reactivity of 15 with that of the
related bis(triisopropylphosphine) analogues [Rh(j2-
O2CR)(PiPr3)2], the reactions of the previously prepared
carboxylato complexes 21 and 25 with various diazoalk-
anes have been investigated. The results are summarized
in Schemes 10 and 11. While the acetato complex 21 re-
acts with N2CC4Cl4 almost instantaneously to give the
1:1 adduct 22 in nearly quantitative yield, the corre-
sponding reactions of 21 with N2CPh2 and
N2C(Ph)C(O)Ph lead to equilibria between the starting
material and compounds 23, 24 which could not be com-
pletely shifted to the side of the products. Since attempts
to separate 21 from 23 or 24 by fractional crystallization
or column chromatography failed, the diazoalkane com-
plexes 23 and 24 could only be characterized by IR and
NMR spectroscopy. In contrast, the diazocyclopentadi-
ene derivative 22 was isolated as a pale-green solid for
which a correct elemental analysis was obtained. The
spectroscopic data of 22–24 are in agreement with a
square-planar arrangement of the four monodentate lig-
ands around the rhodium(I) center and deserve no fur-
ther comments.
C2H4
Cl
Cl
Cl
Cl
PiPr3
PiPr3
Rh
O
Cl
15
+ O2
+ Ph2CN2
Cl
Cl
PiPr3
PiPr3
C6Cl5O Rh
N2CPh2
Cl
Cl
Cl
O
O
Rh
O
PiPr3
18
PiPr3
17
Scheme 7.
as a solid. Among the decomposition products, OPiPr3
could be detected. The increased reactivity of 15 towards
O2 compared with C2H4 is illustrated by the fact that the
solid–gas reaction with oxygen to give 17 is finished after
1 h at room temperature whereas the analogous reaction
with ethene to afford 16 takes 30 h under the same con-
ditions (Scheme 8). In either case, the product is formed
in quantitative yield.
Treatment of 15 with diphenyldiazomethane also
leads to partial opening of the chelate bond and to the
formation of compound 18 (see Scheme 7). Similarly
to the chlororhodium(I) derivative trans-[RhCl(N2C-
Ph2)(PiPr3)2], the phenolato complex 18 is a green air-
sensitive solid that has been characterized by elemental
analysis and spectroscopic techniques. With respect to
the bonding mode, the position of the N–N stretching
vibration at 2024 cmꢀ1 in the IR spectrum suggests an
end-on coordination of the N2CPh2 unit [16]. In the
13C NMR spectrum, the resonance for the N2C carbon
atom appears at d 87.1 as a broad singlet, the broaden-
ing probably being due to the quadrupole moment of
The trifluoracetato compound 25 is significantly more
reactive toward diazoalkanes than the counterpart 21
and upon treatment with N2CPh2, N2CC4Cl4 and
N2CHC(O)Ph in pentane affords the expected 1:1 ad-
ducts 26–28 in good to excellent yields (Scheme 11).
The IR spectra of the green (26, 27) or yellow (28) solids
display a band for the asymmetric OCO stretching mode
C2H4
30 h
H
CH3
R
R2CN2
+
16
[15]cat
- N2
H2C
CH2
R
without solvent
15
r.t.
R
1b, 19, 20
C6H5
1b
19 p-C6H4Me
20 p-C6H4Cl
O2
1 h
17
Scheme 8.
Scheme 9.

H. Werner et al. / Polyhedron 23 (2004) 2645–2657
2649
O
O
PiPr3
PiPr3
H3C
Rh
21
C4Cl4CN2
RR'CN2
Cl
Cl
O
O
O
PiPr3
Cl
Cl
PiPr3
Rh N2CRR'
H3C
H3C
Rh
PiPr3
22
N2
O
PiPr3
23,24
R
R'
Ph Ph
23
C(O)Ph
24 Ph
Scheme 10.
O
PiPr3
N2CRR'
F3C
Rh
O
26-28
R
R'
PiPr3
Ph Ph
C4Cl4
26
27
28
C(O)Ph
H
RR'CN2
O
O
PiPr3
F3C
Rh
PiPr3
25
PhHCN2
1,4-C6H4{C(N2)Ph}2
O
PiPr3
F3C
Rh
N2
O
PiPr3
PiPr3
29
C
N2 Rh
O
CF3
PiPr3
O
O
PiPr3
F3C
O Rh N2
C
30
PiPr3
Scheme 11.
at around 1640–1700 cmꢀ1, which is consistent with the
monodentate coordination of the trifluoracetato ligand
[18]. The bis(diazoalkane) derivative 1,4-C6H4-
{C(N2)Ph}2 behaves similarly to N2CPh2 and reacts
with the starting material 25 in diethylether to give the
dinuclear complex 30. The 31P NMR spectrum of 30
shows a doublet at d 41.9, the chemical shift and the
31P–103Rh coupling constant of which are nearly identi-
cal to those of the corresponding signal for 26.
In contrast to N2CPh2, phenyldiazomethane reacts
with 25 in pentane to give, instead of trans-[Rh(j1-
O2CCF3)(N2CHPh)(PiPr3)2], the dinitrogen complex
29 in 59% yield. Thus, the trifluoracetato compound be-
haves similarly to [RhCl(PiPr3)2]2 which upon treatment

2650
H. Werner et al. / Polyhedron 23 (2004) 2645–2657
Table 1
Data on the catalytic activity and composition of the product in the reaction of ethene and diaryldiazomethanes N2CRR0 (for details see Section 3)
Catalyst
TONa
R,R0
Productb
21
21
21
21
21
21
25
25
25
a
10
13
11
10
6
Ph2
CH2‚CHCHPh2 (1c)
Ph,p-C6H4Me
Ph,o-C6H4Me
(p-C6H4Me)2
(p-C6H4OMe)2
(p-C6H4Cl)2
Ph2
CH2‚CHC(Ph)C6H4Me-p (31)
CH2‚CHC(Ph)C6H4Me-o (32)
CH2‚CHCH(C6H4Me-p)2 (33)
CH2‚CHCH(C6H4OMe-p)2 (34)
CH2‚CHCH(C6H4Cl-p)2 (35)
CH3CH‚CPh2 (1b)
7
33
18
12
(p-C6H4Me)2
(p-C6H4Cl)2
CH3CH‚C(C6H4Me-p)2 (19)
CH3CH‚C(C6H4Cl-p)2 (20)
TON=turnover number=mol product/mol catalyst.
Dominating product, relative amount >94%.
b
PiPr3
O
Rh PiPr3
C
O
21
Me
C2H4
O
L
Me
Ph2CN2
O
Rh
Ph
C2H4
L
N2
O
Ph
O
L
L
CPh2
Me
Me
O
Rh
1c
O
Rh
L
L
D
CHPh2
A
O
Me
L
L
CHPh2
O
O
CPh2
Me
Rh
L
Rh
L
O
H
(L=PiPr3)
C
B
Scheme 12.
with N2CHPh affords trans-[RhCl(N2)(PiPr3)2] [19,20].
Diagnostic for the coordination of the N2 ligand in 29
is the m(N2) stretch at 2098 cmꢀ1 in the IR spectrum,
which is shifted by ca. 160 cmꢀ1 to higher frequency
compared with the N2CPh2 derivative 26. In solution,
compound 29 is less stable than the counterparts 26
and 28 and decomposes slowly to give 25 as the domi-
nating species.
of ethene and diaryldiazomethanes. However, while the
catalytic activity is comparable to that of the pentachlo-
rophenolato analogue 15 (see Scheme 9), the substituent
of the carboxylato unit has a significant influence on the
composition of the coupling product. With 25 as the cat-
alyst, the reaction of C2H4 with N2C(C6H4X)2 (X=H, p-
Me, p-Cl) leads almost exclusively to the formation of
the trisubstituted olefins 1b, 19 and 20 with turnover
numbers (in toluene at 40 ꢁC) of 33 (X=H), 18 (X=p-
Me) and 12 (X=p-Cl), respectively. At the beginning
Both the acetato and the trifluoracetato complexes 21
and 25 are also catalysts for the C–C coupling reaction

H. Werner et al. / Polyhedron 23 (2004) 2645–2657
2651
of the catalytic processes, the formation of the diazoalk-
ane complexes trans-[Rh(j1-O2CCF3)(N2CR2)(PiPr3)2]
radiation of a solution of 21 in C6D6, saturated with
ethene, a hydridorhodium(III) intermediate is generated
that displays in the 1H NMR spectrum a high-field reso-
nance at d – 20.6, i.e., at a similar chemical shift as for
[RhH(j1-O2CCF3)(j2-O2CCF3)(PiPr3)2] (d – 19.0) [22].
In summarizing, the present work extended the series
of chelate rhodium(I) complexes with Rh(PiPr3)2 as the
core unit. These complexes not only react with ethene
but also with diazoalkanes, in particular with N2CPh2
and N2CC4Cl4, by opening of the chelate bond and for-
mation of four-coordinate rhodium(I) derivatives with
the two phosphine ligands in a trans disposition. In
the presence of excess C2H4, compounds such as 15,
21 and 25 catalyze the reaction of ethene and diaryldia-
zomethanes N2CRR0 to give, instead of the anticipated
1,1-disubstituted cyclopropane, either CH3CH‚CRR0
or the isomer CH2‚CHCHRR0 as the main product.
The postulated mechanism for the formation of the ter-
minal olefin, with the acetato complex 21 as the catalyst,
involves a stepwise opening and closing of the chelating
Rh(j2-O2CCH3) bond that allows the metal to maintain
the preferred coordination number of four for rho-
dium(I) and six for rhodium(III). The question whether
instead of compounds such as 15 and 25 the isolated car-
bene complexes trans-[Rh(OPh)(‚CPh2)(PiPr3)2] [16]
1
could be detected by H and 31P NMR spectroscopy.
With catalytic amounts of the acetate 21, the reaction
of ethene and diaryldiazomethanes N2CRR0 takes a dif-
ferent course. In this case, the coupling product is nei-
ther the disubstituted cyclopropane nor the
trisubstituted olefin CH3CH‚CRR0 but, quite remark-
ably, the isomeric monosubstituted ethene derivative
CH2‚CHCHRR0. Thus, formally an insertion of the
carbene :CRR0 into one of the CAH bonds of ethene oc-
curs. The TON values lie between 6 and 13 (see Table 1)
and depend only slightly on the substituents R and R0. If
instead of ethene, propene is treated with N2CPh2 in the
presence of 21 as the catalyst, no reaction occurs under
the same conditions. The coupling products
CH2‚CHCHRR0, of which as far as we know those
with
R=Ph,
R0 =o-C6H4Me,
p-C6H4Me
and
R=R0 =p-C6H4(OMe), p-C6H4Cl have not been de-
scribed in the literature, were characterized by GC–MS
1
and H NMR spectroscopy.
The mechanism of the reaction of ethene and diaryldi-
azomethanes with 21 as the catalyst to give predomi-
nantly the monosubstituted ethene derivative is not
clear as yet. As shown in Scheme 12 with N2CPh2 as
the substrate, we assume that in the initial step, in the
presence of a large excess of ethene, the intermediate
trans-[Rh(j1-O2CCH3)(C2H4)(PiPr3)2] is formed and re-
acts with diphenyldiazomethane to generate the five-co-
ordinate carbene(olefin) compound A. While we have
postulated that on this stage, for chloride instead of ace-
tate as the anionic ligand, ring closure occurs to give a
metallacyclobutane, alternatively an intramolecular
CAH activation could take place to afford the six-coordi-
nate intermediate B. Migration of the hydride ligand
from the metal to the carbene moiety with concomitant
formation of a chelate ring would then give the alkyl(vi-
nyl)rhodium(III) derivative C, that rearranges via intra-
molecular C–C coupling to generate D. With excess
C2H4, the olefinic ligand of D could be replaced to pro-
duce 1c (the isomer of 1a and 1b) and the ethene com-
pound trans-[Rh(j1-O2CCH3)(C2H4)(PiPr3)2], which
can start a new catalytic cycle. To explain the rather
low TON value for 1c and the analogous C–C coupling
products, we assume that in the course of the reaction ei-
ther the initially formed ethene complex or one of the
postulated intermediates decomposes to give free PiPr3
which reacts with the diazoalkane to form the corre-
sponding phosphorus yield. With regard to the CAH ac-
tivation step from A to B, it is worth mentioning that we
recently observed, in the presence of L (pyridine or
PiPr3), the formation of the hydrido(vinyl)iridium(III)
complexes [IrH(CH‚CH2)(j2-acac)(L)(PiPr3)] from
the etheneiridium(I) precursor [Ir(j2-acac)(C2H4)(PiPr3)]
under either photochemical or thermal conditions [21].
Moreover, in a control experiment we found that upon ir-
and
trans-[Rh(j1-O2CCF3)(‚CPh2)(PiPr3)2]
[23]
equally catalyze the reaction of ethene with diphenyldi-
azomethane to give either 1a, 1b or 1c is currently being
investigated in our laboratory.
3. Experimental
3.1. General considerations
All experiments were carried out under an atmos-
phere of argon by Schlenk techniques. Solvents were pu-
rified and degassed by standard procedures. The starting
materials 2–4 [24], 8 [7], 9 [25], 21 and 25 [7] were pre-
pared as described in the literature. PiPr3 was a commer-
cial product from Strem. IR spectra were recorded on a
Perkin–Elmer 1420 infrared spectrometer and NMR
spectra were recorded (if not otherwise mentioned) at
room temperature (r.t.) on Bruker WH 90, Bruker AC
200 and Bruker AMX 400 instruments. Abbreviations
used: s, singlet; d, doublet; t, triplet; q, quartet; m, multi-
plet; br, broadened signal; vt, virtual triplet;
1
N=3J(PH)+5J(PH) or J(PC)+3J(PC). Melting points
were determined by Differential Thermal Analysis
(DTA). The mass spectra were measured on a Finnigan
90 MAT instrument.
3.2. Preparation of [Rh(j2-acac)(C2H4)(PiPr3)] (5)
A solution of 2 (60 mg, 0.23 mmol) in 4 ml of pentane
was treated with PiPr3 (42 ll, 0.23 mmol) and stirred for

2652
H. Werner et al. / Polyhedron 23 (2004) 2645–2657
15 min at r.t. The solvent was evaporated in vacuo and
the orange residue was recrystallized from 1 ml of ace-
tone at ꢀ78 ꢁC: yield 70 mg (81%). The product was
characterized spectroscopically by comparison with ref-
erence data [9].
PCHCH3), 20.7 (s, PCHCH3). 31P NMR (C6D6, 162.0
MHz): d 59.4 [d, J(RhP)=192.1].
1
3.6. Preparation of [Rh(j2-acac-f6)(PiPr3)2] (11)
A solution of 8 (74 mg, 0.16 mmol) in 10 ml of dieth-
ylether was treated with hexafluoroacetylacetone (23 ll,
0.16 mmol) and stirred for 20 min at r.t. The solvent was
evaporated in vacuo and the residue was dissolved in
4 ml of acetone. After the solution was slowly cooled
at ꢀ78 ꢁC, orange crystals precipitated which were sep-
arated from the mother liquor and washed twice with
small amounts of pentane: yield 77 mg (76%), m.p. 88
ꢁC (dec.). Anal. Calc. for C23H43F6O2P2Rh: C, 43.82;
H, 6.87; Rh, 16.32. Found: C, 43.55; H, 6.69; Rh,
15.31%. MS (70 eV): m/z 630 (M+). IR (hexane):
3.3. Preparation of [Rh(j2-acac-f3)(C2H4)(PiPr3)]
(cis- and trans-6)
This compound was prepared as described for 5, with
100 mg (0.32 mmol) of 3 and 62 ll (0.32 mmol) of PiPr3
as starting materials. Orange solid, yield 130 mg (91%),
m.p. 86 ꢁC. Anal. Calc. for C16H29F3O2PRh: C, 43.23;
H, 6.58. Found: C, 42.89; H, 6.71%. Spectroscopic data
1
for cis-6: H NMR (C6D6, 200 MHz): d 5.65 [s, 1H,
CHC(O)], 3.34, 2.76 (both br s, 4H, CH2), 1.77 (m,
1
3H, PCH CH3), 1.52 [s, 3H, CH3C(O)], 1.08 [dd,
3
m(CO) 1541, 1508 cmꢀ1. H NMR (C6D6, 200 MHz): d
3J(PH)=13.0, J(HH)=7.2, 18H, PCHCH3]. 19F NMR
6.27 [s, 1H, CHC(O)], 2.04 (m, 6H, PCHCH3), 1.22
[dd, 3J(PH)=12.8, 3J(HH)=7.3, 36H, PCHCH3]. 13C
NMR (C6D6, 100.6 MHz): d 170.0 [q, 2J(FC)=33.2,
(C6D6, 188.2 MHz): d ꢀ74.5 (s, CF3). 31P NMR
1
(C6D6, 81.0 MHz): d 61.7 [d, J(RhP)=179.8]. Spectro-
1
1
scopic data for trans-6: H NMR (C6D6, 200 MHz): d
CO], 119.8 [q, J(FC)=280.1, CF3], 91.8 [s, CHC(O)],
24.6 (vt, N=21.1 Hz, PCHCH3), 20.3 (s, PCHCH3).
19F NMR (C6D6, 188.2 MHz): d ꢀ75.3 (s). 31P NMR
5.70 [s, 1H, CHC(O)], 3.34, 2.76 (both br s, 4H, CH2),
1.77 (m, 3H, PCHCH3), 1.54 [s, 3H, CH3C(O)], 1.08
[dd, 3J(PH)=13.0, 3J(HH)=7.2, 18H, PCHCH3]. 19F
NMR (C6D6, 188.2 MHz): d ꢀ74.3 (s, CF3). 31P NMR
(C6D6, 81.0 MHz): d 61.3 [d, 1J(RhP)=180.9]. Ratio
of cis-6:trans-6=15:1.
1
(C6D6, 81.0 MHz): d 55.7 [d, J(RhP)=191.8].
3.7. Preparation of [Rh(j2-acac)(N2CC4Cl4)(PiPr3)]
(12)
3.4. Preparation of [Rh(j2-acac-f6)(C2H4)(PiPr3)] (7)
A solution of 5 (86 mg, 0.22 mmol) in 15 ml of pen-
tane was treated at ꢀ78 ꢁC with N2CC4Cl4 (101 mg, 0.44
mmol). After the solution was slowly warmed to 0 ꢁC, it
was stirred for 10 min. The solvent was evaporated in
vacuo, the greenish residue was washed three times with
10 ml portions of pentane (ꢀ78 ꢁC) and dried: yield 87
mg (67%), m.p. 61 ꢁC (dec.). Anal. Calc. for
C19H28Cl4N2O2PRh: C, 38.54; H, 4.77; N, 4.73. Found:
C, 38.26; H, 4.75; N, 4.47%. IR (hexane): m(N2) 1958,
This compound was prepared as described for 5, with
100 mg (0.27 mmol) of 4 and 64 ll (0.33 mmol) of PiPr3
as starting materials. Orange solid, yield 118 mg (91%).
The product was characterized spectroscopically by
comparison with reference data [9].
3.5. Preparation of [Rh(j2-acac)(PiPr3)2] (10)
1
m(CO) 1579, 1510 cmꢀ1. H NMR (C6D6, 200 MHz): d
A solution of 9 (241 mg, 0.26 mmol) in 10 ml of dieth-
ylether was treated with Na(acac) (150 mg, 1.23 mmol)
and stirred for 2 h at r.t. After 30 ml of diethylether were
added, the suspension was filtered and the filtrate was
brought to dryness in vacuo. The residue was dissolved
in 3 ml of boiling acetone and the solution was slowly
cooled at ꢀ78 ꢁC. Yellow crystals precipitated which
were separated from the mother liquor and washed
twice with small amounts of pentane: yield 192 mg
(70%), m.p. 77 ꢁC (dec.). Anal. Calc. for C23H49O2P2Rh:
C, 52.85; H, 9.46; Rh, 19.71. Found: C, 52.39; H, 9.12;
Rh, 19.36%. MS (70 eV): m/z 522 (M+). IR (KBr):
5.15 [s, 1H, CHC(O)], 2.55 (m, 3H, PCHCH3), 1.92,
1.54 [both s, 3H each, CH3C(O)], 1.20 [dd,
3J(PH)=14.2, 3J(HH)=7.2, 18H, PCHCH3]. 13C
NMR (C6D5CD3, 50.3 MHz, 233 K): d 192.0, 182.5
(both s, CO), 109.8, 104.4 (both s, C4Cl4), 101.7 [s,
CHC(O)], 81.7 (br s, N2C), 27.9, 26.8 [both s, CH3C(O)],
23.9 [d, 1J(PC)=24.6 Hz, PCHCH3], 19.7 (s, PCHCH3).
31P NMR (C6D6, 81.0 MHz): d 64.0 [d, 1J(RhP)=164.7].
3.8. Preparation of [Rh(j2-acac-f3)(N2CC4Cl4)-
(PiPr3)] (cis- and trans-13)
1
m(N2) 1958, m(CO) 1579, 1510 cmꢀ1. H NMR (C6D6,
This compound was prepared as described for 12,
with 6 (42 mg, 0.09 mmol) and N2CC4Cl4 (43 mg, 0.19
mmol) in 5 ml of pentane as starting materials. Greenish
solid; yield 48 mg (79%), m.p. 61 ꢁC (dec.). Anal. Calc.
for C19H25Cl4F3N2O2PRh: C, 35.32; H, 3.90; N, 4.34.
Found: C, 35.25; H, 3.99; N, 4.19%. IR (diethylether):
400 MHz): d 5.35 [s, 1H, CHC(O)], 2.18 (m, 6H,
PCHCH3), 1.74 [s, 6H, CH3C(O)], 1.36 [dd,
3J(PH)=12.0, 3J(HH)=7.3, 36 H, PCHCH3]. 13C
NMR (C6D6, 100.6 MHz): d 183.3 (s, CO), 99.8 [s,
CHC(O)], 27.1 [s, CH3C(O)], 24.6 (vt, N=19.1 Hz,

H. Werner et al. / Polyhedron 23 (2004) 2645–2657
2653
m(N2) 1950 cmꢀ1. Spectroscopic data for cis-13: 1H
NMR (C6D5CD3, 200 MHz): d 5.79 [s, 1H, CHC(O)],
2.12 (m, 3H, PCHCH3), 1.87 [s, 3H, CH3C(O)], 1.15
[dd, 3J(PH)=14.2, 3J(HH)=6.9, 18H, PCHCH3]. 13C
NMR (C6D5CD3, 50.3 MHz, 223 K): d 197.3 [s,
3.11. Preparation of trans-[Rh(j1-OC6Cl5)(C2H4)-
(PiPr3)2] (16)
A slow stream of ethene was passed for 1 min
through a solution of 15 (98 mg, 0.14 mmol) in 5 ml
of pentane at r.t. A change of colour from red to yellow
occurred. After the solution was cooled at ꢀ78 ꢁC, light
yellow crystals precipitated which were separated from
the mother liquor, washed twice with small amounts
of pentane (ꢀ78 ꢁC) and dried in a stream of argon:
yield 72 mg (71%), m.p. 38 ꢁC (dec.). Anal. Calc. for
C26H46Cl5OP2Rh: C, 43.57; H, 6.47. Found: C, 43.46;
2
CH3C(O)], 162.8 [q, J(FC)=33.3, CF3C(O)], 118.1 [q,
1J(FC)=283.1, CF3], 110.4, 104.6 (both s, C4Cl4), 97.7
[s, CHC(O)], 84.6 (br s, N2C), 28.8 [s, CH3C(O)], 23.4
1
[d, J(PC)=25.0 Hz, PCHCH3], 19.6 (s, PCHCH3). 31P
NMR (C6D5CD3, 81.0 MHz):
d
66.6 [d,
1J(RhP)=164.3]. Selected spectroscopic data for trans-
13: 1H NMR (C6D5CD3, 200 MHz): d 5.83 [s, 1H,
CHC(O)]. 31P NMR (C6D5CD3, 81.0 MHz): d 65.8 [d,
1J(RhP)=165.2].
1
H, 6.39%. H NMR (C6D6, 200 MHz, 295 K): d 2.34
(br s, 4H, C2H4), 1.71 (m, 6H, PCHCH3), 1.07 [d,
3J(HH)=7.3, 36H, PCHCH3]. 1H NMR (C6D5CD3,
400 MHz, 223 K): d 2.50 (br s, 4H, C2H4), 2.11 (br s,
6H, PCHCH3), 1.25 (br s, 36H, PCHCH3). 13C NMR
(C6D5CD3, 100.6 MHz, 223 K): d 160.4 (s, CO), 131.7,
123.2, 114.6 (all s, C5Cl5), 23.3 (vt, N=15.3, PCHCH3),
20.1 (s, PCHCH3), signal for C2H4 not exactly located.
31P NMR (C6D5CD3, 162.0 MHz, 223 K): d 24.9 [d,
1J(RhP)=125.0]. Compound 16 had alternatively been
prepared by storing the starting material 15 in a Schlenk
tube under an atmosphere of ethene for 30 h at r.t.; the
yield was quantitative.
3.9. Preparation of [Rh(j2-acac-f6)(N2CC4Cl4)-
(PiPr3)] (14)
This compound was prepared as described for 12,
with 7 (144 mg, 0.29 mmol) and N2CC4Cl4 (133 mg,
0.58 mmol) in 15 ml of pentane as starting materials.
Greenish solid; yield 118 mg (58%), m.p. 67 ꢁC (dec.).
Anal. Calc. for C19H22Cl4F6N2O2PRh: C, 32.00; H,
3.17; N, 4.00. Found: C, 31.82; H, 3.06; N, 4.03%.
MS (70 eV): m/z 700 (M+). IR (KBr): m(N2) 1955
cmꢀ1 1H NMR (C6D6, 200 MHz): d 6.15 [s, 1H,
.
CHC(O)], 1.77 (m, 3H, PCHCH3), 0.91 [dd,
3J(PH)=14.7, 3J(HH)=7.2, 18H, PCHCH3]. 13C
NMR (C6D5CD3, 100.6 MHz, 223 K): d 176.5 [q,
2J(FC)=35.2, CF3C(O)], 117.7 [q, 1J(FC)=273.6,
CF3], 111.7, 105.5 (both s, C4Cl4), 91.7 [s, CHC(O)],
87.6 (br s, N2C), 23.1 [d, 1J(PC)=25.7, PCHCH3],
19.0 (s, PCHCH3). 31P NMR (C6D6, 81.0 MHz): d
3.12. Preparation of [Rh(j2-OC6Cl5)(O2)(PiPr3)2]
(17)
A slow stream of O2 was passed for 1 min through a
solution of 15 (72 mg, 0.10 mmol) in 6 ml of pentane at
r.t. The solution was concentrated to ca. 3 ml in vacuo
and then stored at ꢀ78 ꢁC for 12 h. A dark brown
microcrystalline solid precipitated which was separated
from the mother liquor, washed twice with small
amounts of pentane (ꢀ20 ꢁC) and dried: yield 59 mg
(82%), m.p. 48 ꢁC (dec.). Anal. Calc. for
C24H42Cl5O3P2Rh: C, 40.00; H, 5.87. Found: C, 39.73;
1
68.0 [d, J(RhP)=164.6].
3.10. Preparation of [Rh(j2-OC6Cl5)(PiPr3)2] (15)
A solution of 8 (166 mg, 0.36 mmol) in 10 ml of
toluene was treated with a solution of pentachlorophe-
nol (95 mg, 0.36 mmol) in 5 ml of toluene and stirred
for 30 min at r.t. The solvent was evaporated in vacuo
and the residue was extracted with 20 ml of pentane.
The extract was brought to dryness in vacuo and the
residue was recrystallized from acetone at ꢀ78 ꢁC to
give a red microcrystalline solid: yield 179 mg (73%),
m.p. 124 ꢁC (dec.). Anal. Calc. for C24H42Cl5OP2Rh:
C, 41.85; H, 6.15. Found: C, 42.35; H, 6.80%. 1H
NMR (C6D6, 200 MHz): d 2.02 (m, 6H, PCHCH3),
H, 6.02%. IR (CH2Cl2): m(O2) 890 cmꢀ1 1H NMR
.
(C6D6, 200 MHz): d 2.50 (m, 6H, PCHCH3), 1.21 [dvt,
N=13.1, 3J(HH)=7.3, 18H, PCHCH3], 1.13 [dvt,
N=14.2, 3J(HH)=6.9, 18H, PCHCH3]. 13C NMR
(C6D6, 50.3 MHz): d 162.9 (s, CO), 133.5, 131.7,
131.1, 128.3, 123.0 (all s, C5Cl5), 22.3 (vt, N=19.4,
PCHCH3), 19.6, 19.3 (both s, PCHCH3). 31P NMR
(C6D6, 81.0 MHz): d 32.9 [d, 1J(RhP)=98.8]. Com-
pound 16 had alternatively been prepared by storing
the starting material 15 in a Schlenk tube under an
atmosphere of oxygen for 1 h at r.t.; the yield was
quantitative.
3
3
1.22 [dd, J(PH)=12.8, J(HH)=6.9, 36 H, PCHCH3].
13C NMR (C6D6, 50.3 MHz): d 161.8 (s, CO), 129.6,
121.9, 114.2 (all s, C5Cl5), 26.2 (vt, N=20.3,
PCHCH3), 20.6 (s, PCHCH3). 31P NMR (C6D6, 81.0
MHz, 295 K): d 61.2 [d, 1J(RhP)=203.4]. 31P NMR
3.13. Preparation of trans-[Rh(j1-OC6Cl5)(N2CPh2)-
(PiPr3)2] (18)
(C6D5CD3, 162.0 MHz, 213 K):
2
d
60.4 [dd,
1J(RhP)= 162.8, J(PP)= 47.0, PiPr3 cis to Cl], 59.2
A solution of 15 (76 mg, 0.11 mmol) in 10 ml of pen-
tane was treated dropwise at ꢀ78 ꢁC with a solution of
1
[dd, J(Rh P)=114.7, J(PP)=47.0, PiPr3 trans to Cl].
2

2654
H. Werner et al. / Polyhedron 23 (2004) 2645–2657
diphenyldiazomethane (22 mg, 0.11 mmol) in 2 ml of
pentane. While the solution was warmed to r.t., a
change of colour first from red to dark brown and then
to green occurred. The solution was stirred for 5 min at
r.t. and then concentrated to ca. 2 ml in vacuo. After it
was stored at ꢀ78 ꢁC for 12 h, dark green crystals pre-
cipitated which were separated from the mother liquor,
washed twice with small amounts of pentane (ꢀ20 ꢁC)
and dried: yield 70 mg (72%), m.p. 43 ꢁC (dec.). Anal.
Calc. for C37H52Cl5N2OP2Rh: C, 50.33; H, 5.94; N,
3.17. Found: C, 49.97; H, 5.90; N, 2.82.%. IR (hexane):
m(N2) 2043 cmꢀ1. 1H NMR (C6D6, 200 MHz): d 7.30 (m,
4H, C6H5), 7.14–6.97 (br m, 6H, C6H5), 1.97 (m, 6H,
PCHCH3), 1.18 [dvt, N=13.2, 3J(HH)=6.2, 36 H,
PCHCH3]. 13C NMR (C6D6, 50.3 MHz): d 161.8 (s,
CO), 139.8, 132.0, 130.2, 129.7, 129.1, 128.9, 126.7 (all
s, C6H5 and C5Cl5), 87.1 (br s, N2C), 23.3 (vt,
N=17.6, PCHCH3), 19.4 (s, PCHCH3). 31P NMR
nyldiazomethane (71 mg, 0.36 mmol) in 4 ml of
diethylether. A change of colour from red to green oc-
curred. The solution was warmed to r.t., stirred for
10 min, and the solvent was evaporated in vacuo. The
residue was dissolved in 10 ml of pentane and the solu-
tion was stored at ꢀ78 ꢁC for 6 h. A greenish-brown sol-
id precipitated which was separated from the mother
liquor, washed with small amounts of pentane (0 ꢁC)
and dried. The NMR spectra revealed that a mixture
of 21 and 23 in the ratio of 1:2 was isolated. Attempts
to separate the two compounds by fractional crystalliza-
tion or chromatographic techniques failed. If the reac-
tion was repeated by using a 10-fold excess of
N2CPh2, a mixture of 21 and 23 in the approximate ratio
of 1:3 was isolated. Spectroscopic data for 23: IR (KBr):
1
(N2) 1950, m(CO2) 1635, 1495 cmꢀ1. H NMR (C6D6,
200 MHz): d 7.40–6.83 (br m, 10H, C6H5), 2.06 (m,
6H, PCHCH3), 2.00 (s, 3H, CH3CO2), 1.28 [dvt,
N=13.5, 3J(HH)=6.6, 36H, PCHCH3]. 13C NMR
(C6D6, 50.3 MHz): d 174.1 (s, CO2), 79.4 (br s, N2C),
24.0 (vt, N=17.3 Hz, PCHCH3), 20.6 (s, CH3CO2),
20.0 (s, PCHCH3), signals for phenyl protons were part-
ly covered by the solvent signal. 31P NMR (C6D6, 81.0
1
(C6D6, 81.0 MHz): d 37.8 [d, J(RhP)=130.8].
3.14. Catalytic reaction of ethene with diaryldiazometh-
anes with compound 15 as a catalyst
1
In an NMR tube, a slow stream of ethene was passed
for 30 s through a solution of 15 (25 mg, 0.03 mmol) and
N2CR2 (0.10 mmol) (R=Ph, p-C6H4Me, p-C6H4Cl) in
0.5 ml of C6D6 at r.t. After the solution was warmed
to 40 ꢁC, the formation of the olefins 1b [26], 19 [27],
MHz): d 42.5 [d, J(RhP)=130.8].
3.17. Generation of trans-[Rh(j1-O2CCH3){N2C(Ph)-
C(O)Ph}(PiPr3)2] (24)
1
20 [28] was detected by H NMR spectroscopy. After
The reaction of 21 (63 mg, 0.13 mmol) with
N2C(Ph)C(O)Ph (29 mg, 0.13 mmol) in diethylether
was carried out as described above with N2CPh2 as
the substrate. No change of colour occurred. A red solid
was isolated which, owing to the NMR spectra, consist-
ed of a mixture of 21 and 24 in the ratio of 1:4. Attempts
to separate the two compounds failed. Spectroscopic da-
30 min, the catalyst decomposed and no Rh-containing
product could be characterized.
3.15. Preparation of trans-[Rh(j1-O2CCH3)(N2C-
C4Cl4)(PiPr3)2] (22)
1
A solution of 21 (38 mg, 0.08 mmol) in 10 ml of pen-
tane was treated at ꢀ78 ꢁC with N2CC4Cl4 (18 mg, 0.08
mmol). After the solution was slowly warmed to r.t., it
was stirred for 10 min. The solvent was evaporated in va-
cuo and the greenish residue was recrystallized from pen-
tane at ꢀ78 ꢁC: yield 45 mg (80%), m.p. 85 ꢁC (dec.).
Anal. Calc. for C25H45Cl4N2O2P2Rh: C, 47.16; H, 6.37;
N, 3.93. Found: C, 48.02; H, 6.67; N, 3.27%. IR (KBr):
ta for 24: IR (KBr): m(N2) 1920 cmꢀ1. H NMR (C6D6,
400 MHz): d 7.96, 7.86 (both m, 2H each, C6H5), 7.20–
6.77 (br m, 6H, C6H5), 2.43 (m, 6H, PCHCH3), 1.67 (s,
3H, CH3CO2), 1.28, 1.27 [both dvt, N=13.4,
3J(HH)=7.0, 18H each, PCHCH3]. 13C NMR (C6D6,
100.6 MHz): d 181.4 (s, CO2), 158.1 (s, C‚O), 108.8
(br s, N2C), 23.4 (vt, N=17.3 Hz, PCHCH3), 20.5 (s,
CH3CO2), 19.9, 19.8 (both s, PCHCH3), signals for phe-
nyl protons were partly covered by the solvent signal.
1
m(N2) 1930, m(CO2) 1625 cmꢀ1. H NMR (C6D6, 200
MHz): d 2.00 (m, 6H, PCHCH3), 1.73 (s, 3H, CH3CO2),
31P NMR (C6D6, 162.0 MHz):
1J(RhP)=113.4].
d
29.9 [d,
3
1.13 [dvt, N=13.9, J(HH)=7.1, 36H, PCHCH3]. 13C
NMR (C6D6, 50.3 MHz): d 174.4 (s, CO2), 102.0, 109.3
(both s, C4Cl4), 85.1 (br s, N2C), 24.4 (vt, N=19.0 Hz,
PCHCH3), 22.7 (s, CH3CO2), 19.7 (s, PCHCH3). 31P
NMR (C6D6, 81.0 MHz): d 46.0 [d, 1J(RhP)=117.7].
3.18. Preparation of trans-[Rh(j1-O2CCF3)(N2CPh2)-
(PiPr3)2] (26)
A solution of 25 (44 mg, 0.08 mmol) in 10 ml of
pentane was treated at ꢀ78 ꢁC with a solution of
diphenyldiazomethane (18 mg, 0.08 mmol) in 2 ml
of pentane. A change of colour from red to green oc-
curred. The solution was warmed to r.t., stirred for 10
min, and the solvent was evaporated in vacuo. The
3.16. Generation of trans-[Rh(j1-O2CCH3)(N2CPh2)-
(PiPr3)2] (23)
A solution of 21 (80 mg, 0.18 mmol) in 30 ml of dieth-
ylether was treated at ꢀ30 ꢁC with a solution of diphe-

H. Werner et al. / Polyhedron 23 (2004) 2645–2657
2655
residue was recrystallized from pentane at ꢀ78 ꢁC to
give a green microcrystalline solid. This was separated
from the mother liquor, washed with small amounts
of pentane (ꢀ20 ꢁC) and dried: yield 44 mg (73%),
m.p. 52 ꢁC (dec.). Anal. Calc. for C33H52F3N2O2P2Rh:
C, 54.25; H, 7.17; N, 3.83. Found: C, 53.94; H, 7.09;
3.21. Preparation of trans-[Rh(j1-O2CCF3)(N2)-
(PiPr3)2] (29)
A solution of 25 (59 mg, 0.12 mmol) in 5 ml of pen-
tane was treated at ꢀ50 ꢁC with a solution of phenyldi-
azomethane (13 mg, 0.12 mmol) in 1 ml of pentane.
While the solution was warmed to r.t., a brown solid
precipitated. The suspension was stirred for 5 min, con-
centrated to ca. 2 ml in vacuo and then stored for 6 h at
ꢀ78 ꢁC. A brown microcrystalline solid was obtained,
which was separated from the mother liquor, washed
with small amounts of pentane (ꢀ20 ꢁC) and dried: yield
40 mg (59%), m.p. 91 ꢁC (dec.). Anal. Calc. for
C20H42F3N2O2P2Rh: C, 42.56; H, 7.50; N, 4.96. Found:
C, 43.02; H, 7.21; N, 5.36%. IR (KBr): m(N2) 2098,
N, 3.50%. IR (KBr): m(N2) 1936, m(CO2) 1640 cmꢀ1
.
1H NMR (C6D6, 200 MHz): d 7.70–6.84 (br m,
10H, C6H5), 1.97 (m, 6H, PCHCH3), 1.20 [dvt,
N=13.5, 3J(HH)=6.9, 36H, PCHCH3]. 13C NMR
(C6D6, 50.3 MHz): d 160.6 [q, 2J(CF)=35.6, CO2],
129.0, 128.8, 125.4, 125.1 (all s, C6H5), 120.4 [q,
1J(CF)=277.2, CF3], 81.0 (br s, N2C), 23.7 (vt,
N=17.6, PCHCH3), 19.8 (s, PCHCH3). 19F NMR
(C6D6, 188.3 MHz): d ꢀ74.6 (s). 31P NMR (C6D6,
1
1
81.0 MHz): d 42.2 [d, J(RhP)=126.4].
m(CO2) 1650 cmꢀ1. H NMR (C6D6, 200 MHz): d 2.03
(m, 6H, PCHCH3), 1.22 [dvt, N=13.5, 3J(HH)=7.3,
36 H, PCHCH3]. 13C NMR (C6D6, 50.3 MHz): d
3.19. Preparation of trans-[Rh(j1-O2CCF3)(N2CC4Cl4)-
(PiPr3)2] (27)
2
1
159.7 [q, J(CF)=35.7, CO2], 116.5 [q, J(CF)=255.1,
CF3], 23.3 (vt, N=19.1, PCHCH3), 19.7 (s, PCHCH3).
19F NMR (C6D6, 188.3 MHz): d ꢀ74.6 (s). 31P NMR
This compound was prepared as described for 26,
with 25 (64 mg, 0.12 mmol) and N2CC4Cl4 (27 mg,
0.12 mmol) as starting materials. Greenish microcrys-
talline solid; yield 83 mg (92%), m.p. 111 ꢁC (dec.).
Anal. Calc. for C25H42Cl4F3N2O2P2Rh: C, 39.18; H,
5.52; N, 3.65. Found: C, 38.87; H, 5.36; N, 3.38%.
1
(C6D6, 81.0 MHz): d 43.3 [d, J(RhP)=126.3].
3.22. Preparation of trans,trans-[{Rh(j1-O2CCF3)-
(PiPr3)2}{l-1.4-C6H4(C(Ph)N2)2}] (30)
IR (KBr): m(N2) 1940, m(CO2) 1700 cmꢀ1
.
1H NMR
A solution of 25 (74 mg, 0.14 mmol) in 5 ml of dieth-
ylether was treated dropwise at ꢀ78 ꢁC with a solution
of 1.4-C6H4(C(Ph)N2)2 (26 mg, 0.08 mmol) in 3 ml of di-
ethylether. A change of colour from red to green oc-
curred. The work-up procedure was the same as
described for 26. A dark green microcrystalline solid
was obtained: yield 65 mg (68%), m.p. 46 ꢁC (dec.).
Anal. Calc. for C60H92F6N4O4P4Rh2: C, 52.10; H,
7.14; N, 4.05. Found: C, 52.67; H, 7.41; N, 3.91%. IR
(C6D6, 200 MHz): d 1.93 (m, 6H, PCHCH3), 1.10
[dvt, N=14.1, 3J(HH)=7.1, 36H, PCHCH3]. 13C
NMR (C6D6, 50.3 MHz): d 159.6 [q, 2J(FC)=36.1,
CO2], 119.5 [q, 1J(FC)=278.3, CF3], 110.2, 102.8
(both s, C4Cl4), 86.6 (br s, N2C), 24.1 (vt, N=19.4,
PCHCH3), 19.8 (s, PCHCH3). 19F NMR (C6D6,
188.3 MHz): d ꢀ74.4 (s). 31P NMR (C6D6, 81.0
1
MHz): d 46.5 [d, J(RhP)=114.8].
(KBr): m(N2) 1930, m(CO2) 1630 cmꢀ1
.
1H NMR
3.20. Preparation of trans-[Rh(j1-O2CCF3){N2CH-
C(O)Ph}(PiPr3)2] (28)
(C6D6, 400 MHz): d 7.88–6.89 (br m, 14H, C6H4 and
C6H5), 2.00 (m, 12H, PCHCH3), 1.24 [dvt, N=13.6,
3J(HH)=6.8, 72 H, PCHCH3]. 13C NMR (C6D6, 100.6
MHz): d 160.3 [q, 2J(CF)=35.1, CO2], 129.1, 127.9,
125.6, 125.5, 125.3, 124.5 (all s, C6H4 and C6H5),
This compound was prepared as described for 26,
with 25 (54 mg, 0.10 mmol) and N2CC4Cl4 (27 mg,
0.12 mmol) as starting materials. Yellow microcrystal-
line solid; yield 62 mg (90%), m.p. 56 ꢁC (dec.). Anal.
Calc. for C28H50F3N2O3P2Rh: C, 49.27; H, 7.09; N,
4.10. Found: C, 49.48; H, 7.31; N, 3.87%. IR (KBr):
1
122.4 [q, J(CF)=262.6, CF3], 81.2 (br s, N2C), 23.8
(vt, N=17.5, PCHCH3), 19.9 (s, PCHCH3). 19F NMR
(C6D6, 376.5 MHz): d ꢀ74.8 (s). 31P NMR (C6D6,
1
81.0 MHz): d 42.21.9 [d, J(RhP)=126.3].
m(N2) 1940, m (CO2) 1685, m(C‚O) 1625 cmꢀ1 1H
.
NMR (C6D6, 200 MHz): d 8.28–7.14 (br m, 5H,
C6H5), 2.20 (m, 6H, PCHCH3), 1.42 (s, 1H, N2CH),
1.20 [dvt, N=14.6, 3J(HH)=7.6, 36 H, PCHCH3].
3.23. Catalytic reaction of ethene with diaryldiazometh-
anes with compound 21 or 25 as a catalyst
13C NMR (C6D6, 50.3 MHz):
d
163.2 [q,
In a typical experiment, a solution of the catalyst (20–
30 mg, ca. 0.05 mmol) in 6 ml of toluene was treated drop-
wise (ca. 10 ml/h) at 40 ꢁC with a 0.1 M solution of
N2CRR0 in toluene. While adding the substrate, a slow
stream of ethene was passed through the solution. The
catalytic reaction was finished when the violet colour of
the diazoalkane solution did not disappear on further
2J(FC)=34.7, CO2], 150.1 (s, C‚O), 136.1, 128.8,
128.1, 126.6 (all s, C6H5), 122.6 [q, 1J(FC)=287.8,
CF3], 83.5 (br s, N2C), 24.0 (vt, N=17.8, PCHCH3),
19.6, 19.4 (both s, PCHCH3). 19F NMR (C6D6,
188.3 MHz): d ꢀ74.1 (s). 31P NMR (C6D6, 81.0
1
MHz): d 31.5 [d, J(RhP)=117.1].

2656
H. Werner et al. / Polyhedron 23 (2004) 2645–2657
[2] (a) J. Wolf, L. Brandt, A. Fries, H. Werner, Angew. Chem., Int.
Ed. Engl. 29 (1990) 510;
addition to the reaction mixture. The solvent was evapo-
rated in vacuo and the oily residue was dissolved in 3 ml of
hexane. In order to destroy the excess of N2CRR0 and sep-
arate the catalyst, the mixture was filtered through Al2O3
(neutral, activity grade III, height of column 4 cm). After
removal of the solvent, a colorless oil was isolated from
the eluate. The product was analyzed by GC–MS and
(b) H. Werner, J. Organomet. Chem. 475 (1994) 45.
[3] (a) L. Brandt, Dissertation, Universita¨t Wu¨rzburg, 1991;
(b) A. Fries, Dissertation, Universita¨t Wurzburg, 1993.
¨
[4] (a) A.J. Anciaux, A.J. Hubert, A.F. Noels, N. Petiniot, P. Teyssie,
J. Org. Chem. 45 (1980) 695;
(b) M.P. Doyle, Acc. Chem. Res. 19 (1986) 348;
(c) M.P. Doyle, W.R. Winchester, J.A.A. Hoorn, V. Lynch, S.H.
Simonsen, R. Ghosh, J. Am. Chem. Soc. 115 (1993) 9968.
[5] (a) M.P. Doyle, D. van Leusen, W.H. Tamblyn, Synthesis (1981)
787;
1
the dominating olefin (see Table 1) characterized by H
NMR spectroscopy. The data for 1b [26], 1c [29], 19
[27], 20 [28] and 33 [30] were already reported. 1H NMR
data for N2CRR0 (C6D6, 200 MHz): 31: d 7.83, 7.77 [both
(b) M.P. Doyle, W.H. Tamblyn, W.E. Buhro, R.L. Dorow,
Tetrahedron Lett. (1981) 1783.
3
d, J(HH)=8.2, 2 H each, C6H4], 7.62–7.12 (br m, 5H,
C6H5), 6.31 [ddd, 3J(HH)trans =17.2, 3J(HH)cis =10.2,
[6] L. Brandt, A. Fries, N. Mahr, H. Werner, J. Wolf, in: H. Werner,
A.G. Griesbeck, W. Adam, G. Bringmann, W. Kiefer (Eds.),
Selective Reactions of Metal-activated Molecules, Vieweg Verlag,
Braunschweig, 1992, p. 171.
3J(HH)=7.3,
1
H,
CH‚CH2],
5.22
[ddd,
2
4
3J(HH)cis =10.2, J(HH)=1.5, J(HH)=1.1, 1 H, one H
3
[7] H. Werner, M. Scha¨fer, O. Nurnberg, J. Wolf, Chem. Ber. 127
¨
(1994) 27.
of ‚CH2 trans to CH], 5.01 [ddd, J(HH)trans =17.2,
2J(HH)=1.5, J(HH)=1.8, 1 H, one H of ‚CH2 cis to
4
[8] M.E. Schneider, H. Werner, in: 10. International Symposium on
Homogeneous Catalysis, Princeton, 1996.
[9] R. Daus, Dissertation, Universita¨t Wurzburg, 1990.
¨
CH], 4.72 [br d, 3J(HH)=7.3, 1H, CHRR0], 2.39 (s, 3H,
C6H4CH3). 32: d 7.31–6.82 (br m, 9H, C6H4 and C6H5),
6.18
[ddd,
3J(HH)trans =16.8,
3J(HH)cis =10.2,
[10] M.A. Esteruelas, F.J. Lahoz, E. Onate, L.A. Oro, R. Rodriguez,
P. Steinert, H. Werner, Organometallics 15 (1996) 3436.
[11] H. Werner, N. Mahr, J. Wolf, A. Fries, M. Laubender, E. Bleuel,
R. Garde, P. Lahuerta, Organometallics 22 (2003) 3566.
[12] L.G. Kuzmina, Yu.T. Struchkov, Koord. Chim. 14 (1988) 1262.
[13] L.G. Kuzmina, Yu.T. Struchkov, Sov. J. Coord. Chem. 14 (1988)
712.
3J(HH)=6.6, 1H, CH‚CH2], 5.12 [ddd, 3J(HH)cis =10.2,
2J(HH)=1.5, 4J(HH)=1.5, 1H, one H of ‚CH2 trans to
3
CH], 4.81 [br d, J(HH)=6.6, 1H, CHRR0], 4.75 [ddd,
3J(HH)trans =17.2, J(HH)=1.5, J(HH)=1.8, 1H, one
2
4
H of ‚CH2 cis to CH], 2.18 (s, 3H, C6H4CH3). 34: d
3
3
[14] M.A. Tena, O. Nurnberg, H. Werner, Chem. Ber. 126 (1993)
¨
1597.
7.28 [d, J(HH)=8.4, 4H, C6H4], 7.02 [d, J(HH)=8.8,
4H, C6H4], 6.44 [ddd, 3J(HH)trans =17.2, 3J(HH)cis =10.2,
3J(HH)=6.5, 1H, CH‚CH2], 5.36 [br d, 3J(HH)cis =10.2,
1H, one H of ‚CH2 trans to CH], 5.14 [ddd,
[15] (a) B. Windmuller, J. Wolf, H. Werner, J. Organomet. Chem. 502
¨
(1995) 147;
(b) B. Windmuller, O. Nurnberg, J. Wolf, H. Werner, Eur. J.
¨ ¨
Inorg. Chem. (1999) 613.
2
4
3J(HH)trans =17.2, J(HH)=1.5, J(HH)=1.4, 1H, one
3
[16] (a) Inter alia: A. Albini, H. Kisch, Top. Curr. Chem. 65 (1976)
105;
H of ‚CH2 cis to CH], 4.82 [br d, J(HH)=7.3, 1H,
CHRR0], 2.94 (s, 3H, OCH3). 35:
d 7.90 [d,
(b) W.A. Herrmann, Angew. Chem., Int. Ed. Engl. 17 (1978) 800;
(c) M. Hidai, Y. Mizobe, M. Sato, T. Kodama, Y. Uchida, J.
Am. Chem. Soc. 100 (1978) 5740;
3J(HH)=8.4, 4H, C6H4], 7.40 (m, 4H, C6H4), 6.38 [ddd,
3J(HH)trans =17.2, 3J(HH)cis =10.2, 3J(HH)=6.9, 1H,
CH‚CH2], 5.42 [ddd, 3J(HH)cis =10.2, 2J(HH)=1.5,
4J(HH)=1.2, 1H, one H of ‚CH2 trans to CH], 5.14
[ddd, 3J(HH)trans =17.2, 2J(HH)=1.5, 4J(HH)=1.2, 1H,
(d) J.A. Ibers, T.R. Gaffney, K.D. Schramm, Coord. Chem. Rev.
21 (1980) 141;
(e) D. Sutton, Chem. Rev. 93 (1993) 995.
[17] R.K. Harris, Can. J. Chem. 42 (1964) 2275.
[18] (a) S.D. Robinson, M.F. Uttley, J. Chem. Soc. (1973) 1912;
(b) G.B. Deacon, R.J. Philips, Coord. Chem. Eev. 33 (1980) 227;
(c) D.A. Tocher, R.O. Gould, T.A. Stephenson, M.A. Bennett,
J.P. Ennett, T.W. Matheson, L. Sawyer, V.K. Shah, J. Chem.
Soc., Dalton Trans. (1983) 1571.
3
one H of ‚CH2 cis to CH], 4.85 [br d, J(HH)=7.3,
1H, CHRR0].
Acknowledgements
[19] J. Wolf, unpublished results, 1990.
[20] (a) For the preparation and structural characterization of trans-
[RhCl(N2)(PiPr3)2] see: C. Busetto, A. DÕAlfonso, F. Maspero,
G. Perego, A. Zazzetta, J. Chem. Soc., Dalton Trans. (1977) 1828;
(b) D.L. Thorn, T.H. Tulip, J.A. Ibers, J. Chem. Soc., Dalton
Trans. (1979) 2022.
Financial support from the Fonds der Chemischen
Industrie and BASF AG, Ludwigshafen, is gratefully ac-
knowledged. We also thank Mrs. R. Schedl and Mr.
C.P. Kneis for elemental analyses and DTA measure-
ments, Dr. G. Lange and Mr. F. Dadrich for the mass
spectrum, and Dr. J. Wolf for valuable advice.
[21] B. Papenfuhs, N. Mahr, H. Werner, Organometallics 12 (1993)
4244.
[22] M. Scha¨fer, J. Wolf, H. Werner, J. Organomet. Chem. 476 (1994)
85.
[23] E. Bleuel, B. Weberndo¨rfer, H. Werner, J. Organomet. Chem.
617–618 (2001) 502.
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