New aryl phosphinite ligands avoiding ortho-metallation: Synthesis and molecular structures of trans-[PdCl2(PPh2OR)2] and trans-[Rh(CO)Cl(PPh2OR)2] (R = 2,4,6-Me 3C6H2

Article abstract of DOI:10.1016/j.ica.2005.04.041

The new aryl phosphinites PPh₂OR (R = 2,4,6-Me₃C ₆H₂, 1; R = 2,6-Ph₂C₆H₃, 2) have been prepared from chlorodiphenylphosphine and the corresponding phenols. In these ligands, the

Full text of DOI:10.1016/j.ica.2005.04.041

Inorganica Chimica Acta 358 (2005) 3417–3422
www.elsevier.com/locate/ica
New aryl phosphinite ligands avoiding ortho-metallation:
Synthesis and molecular structures of trans-[PdCl2(PPh2OR)2] and
trans-[Rh(CO)Cl(PPh2OR)2] (R = 2,4,6-Me3C6H2; 2,6-Ph2C6H3)
*
Ludovic Chahen, Lydia Karmazin-Brelot, Georg Suss-Fink
¨
´ ˆ ˆ
Institut de Chimie, Universite de Neuchatel, Case postale 2, CH-2000 Neuchatel, Switzerland
Received 3 March 2005; accepted 26 April 2005
Available online 13 June 2005
Abstract
The new aryl phosphinites PPh2OR (R = 2,4,6-Me3C6H2, 1; R = 2,6-Ph2C6H3, 2) have been prepared from chlorodiphenylphos-
phine and the corresponding phenols. In these ligands, the ortho-positions of the aromatic phosphite function are blocked by methyl
and phenyl substituents, which allows coordination to metal centres without ortho-metallation. Thus, reaction with [PdCl2(cod)]
leads to the complexes trans-[PdCl2(PPh2OR)2] (R = 2,4,6-Me3C6H2, 3; R = 2,6-Ph2C6H3, 4), while the reaction with [Rh2(CO)4Cl2]
gives trans-[Rh(CO)Cl(PPh2OR)2] (R = 2,4,6-Me3C6H2, 5; R = 2,6-Ph2C6H3, 6). The single-crystal X-ray structure analyses of 3 and
5 confirm the trans-coordination of the new ligands in these square-planar complexes.
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Palladium; Rhodium; ortho-Metallation; Aryl phosphinite ligands
1. Introduction
Of particular interest in this respect was the use of
palladacyclic complexes for carbon–carbon coupling
reactions, an area initiated by Beller et al. [3] and the
introduction of palladacyclic pincer compounds by Bed-
ford et al. [4–6]. However, these complexes are so reac-
tive that it is generally not possible to detect the catalytic
active species or even to recover the palladium catalyst
at the end of the reaction.
The most active palladacycles and pincer compounds
contain phosphinite ligands and a carbon–palladium
bond formed by an aromatic-carbon atom in ortho-
position (ortho-metallation) (Scheme 1). Indeed, since
ortho-metallation occurs very easily in palladium com-
plexes containing aromatic phosphorous ligands, there
are only a very few palladium complexes containing aro-
matic phosphinite ligands without undergoing ortho-
metallation. The only complex known so far, to the best
of our knowledge, is the fluoro substituted complex
[PdCl2{PPh2(OC6F5)}2], synthesized by Ziolkowski
and co-workers [7], the molecular structure of which,
Because of their remarkable catalytic potential and
their large versatility, palladium complexes have become
the most popular organometallics used in organic syn-
thesis [1]. In particular, most of carbon–carbon bond
forming reactions such as Heck reaction, Stille reaction,
Suzuki reaction and other C–C couplings are palladium-
catalyzed [2]. One of the intrinsic problems of palla-
dium-catalyzed reactions, the palladium contamination
of the products, not acceptable in the production of
pharmaceuticals or other fine chemicals, can be over-
come by using highly active palladium catalysts, present
in very low concentration. Therefore, the development
of new highly active palladium catalysts that can be used
in low loadings is an ongoing challenge in organometal-
lic chemistry.
*
Corresponding author.
E-mail address: ludovic.chahen@unine.ch (L. Chahen).
0020-1693/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.04.041

3418
L. Chahen et al. / Inorganica Chimica Acta 358 (2005) 3417–3422
CDCl3): d = 7.99–7.85(m, 4H), 7.61–7.55(m, 6H),
7.01(s, 2H), 2.46(s, 3H), 2.24(s, 6H). 13C (CDCl3,
100 MHz): d = 152.81(Ar), 142.37(Ar), 133.08(Ar),
131.57(Ar), 130.29(Ar), 129.41(Ar), 128.38(Ar), 127.06
(Ar), 22.18(CH3), 19.36(CH3). 31P (81 MHz, CDCl3):
d = 113.98 (s). ESI-MS (m/z): 455.3, [2M ꢁ (PPh2)]+.
Anal. Calc.: C, 78.73; H, 6.61. Found: C, 78.53; H,
6.69%.
Scheme 1.
however, is not known. ortho-Metallation has been
shown to occur through the intermediacry of agostic
interactions in the case of square-planar carbonyl rho-
dium complexes by Milstein and co-workers [8], who
succeeded to characterize the agostic intermediate
[Hꢀ ꢀ ꢀC6H3{CH2P(t-Bu)2}2Rh(CO)]+ by X-ray crystal-
lography of the triflate salt.
For these reasons we decided to design new phosph-
inite ligands in which the ortho-positions of the aromatic
cycle with respect to the oxygen substituent are blocked,
so that ortho-metallation cannot take place, and to study
the coordination of these ligands to dichloropalladium
and to chlorocarbonyl rhodium moieties.
2.2. Synthesis of (2,6-diphenylphenyl)-
diphenylphosphinite (2)
A solution of 738 mg (3 mmol) of 2,6-diphenylphenol
and 420 lL (3 mmol) of triethylamine in toluene
(10 mL) was stirred for 5 min. Then, 540 lL (3 mmol)
of chlorodiphenylphosphine were added, which caused
immediately a white precipitate of ammonium chloride.
The mixture was then heated to 90 ꢁC over a period of
18 h under vigorous stirring. After cooling, the mixture
was filtered through a canula equipped with filter-paper.
The filtrate was reduced to dryness in vacuo, and the
resulting residue was washed with methanol (5 mL).
The expected product was extracted with hot hexane
(10 mL) and precipitated upon cooling. The white pre-
cipitate was isolated by filtration and recrystallized from
hexane (65% yield). 1H (400 MHz, CDCl3): d = 7.62–
7.57(m, 4H), 7.55–7.43(m, 4H), 7.43–7.38(m, 2H),
7.33–7.28(m, 4H), 7.20–7.14(m, 5H), 7.10–7.02(m, 4H).
13C (CDCl3, 100 MHz): d = 152.19(Ar), 139.41(Ar),
136.26(Ar), 131.05(Ar), 130.81(Ar), 130.44(Ar), 129.29
(Ar), 128.31(Ar), 128.10(Ar), 128.03(Ar), 127.34(Ar),
124.00(Ar). 31P (81 MHz, CDCl3): d = 120.96 (s) EI-
MS (m/z): 429.0, [M ꢁ H]+. Anal. Calc.: C, 83.70; H,
5.39. Found: C, 83.46; H, 5.60%.
2. Experimental
All reactions were carried out by using standard
Schlenk techniques under argon atmosphere. The sol-
vent n-hexane was distilled from sodium benzophenone
under N2 to avoid water and oxygen contaminations.
Toluene and methanol were purchased from Merck
and were only deoxygenated before use. Methylene chlo-
ride was distilled over CaH2 and saturated with N2.
Chlorodiphenyl phosphine 95% was purchased from Al-
drich and distillated under reduced pressure prior to use.
Deuterated chloroform was used as received, and all
NMR spectra were performed with Varian or Bruker
2.3. General method for the synthesis of complexes 3–6
1
spectrometers (200 and 400 MHz for H, 81 MHz for
31P, and 100 MHz for 13C).
A solution of 1.5 mmol of the corresponding phosph-
inite ligand and 0.75 mmol of [PdCl2(cod)] or
0.375 mmol of [Rh2Cl2(CO)4] in methylene chloride
(20 mL) was stirred at room temperature for 24 h. After
filtration through filter-paper, the solution was reduced
in vacuo to half of its volume. Upon dropwise addition
of n-hexane, a yellow solid precipitated. The yellow pre-
cipitate was isolated by filtration, washed with n-hexane
and dried in vacuo.
2.1. Synthesis of (2,4,6-trimethylphenyl)-
diphenylphosphinite (1)
A solution of 408 mg (3 mmol) of 2,4,6-trimethylphe-
nol and 420 lL (3 mmol) of triethylamine in toluene
(10 mL) was stirred for 5 min. Then, 540 lL (3 mmol)
of chlorodiphenylphosphine were added, which caused
immediately a white precipitate of ammonium chloride.
The mixture was then heated to 90 ꢁC over a period of
18 h under vigorous stirring. After cooling, the mixture
was filtered through a canula equipped with filter-paper.
The filtrate was reduced to dryness in vacuo, the result-
ing oil was dissolved in hexane (5 mL). The cloudy solu-
tion was filtrated through filter-paper, and the solvent of
the filtrate was evaporated under reduced pressure to
give a pale yellow oil (yield 70%). 1H (200 MHz,
2.3.1. trans-[PdCl2{PPh2O(2,4,6-Me3C6H2)}2] (3)
1
(85% yield) H (100 MHz, CDCl3): d = 7.80–7.60(m,
8H), 7.45–7.28(m, 12H), 6.89(s, 4H), 2.39(s, 6H),
2.26(s, 12H). 31P (81 MHz, CDCl3): d = 105.01 (s). 13C
(CDCl3, 100 MHz): d = 134.95(2C Ar), 133.60(2C Ar),
132.08(8C Ar), 130.66(4C Ar), 130.45(2C Ar),
129.48(4C Ar), 129.07(4C Ar), 127.60(8C Ar),
20.86(2C Me), 19.11(4C Me). ESI-MS (m/z): 781.0

L. Chahen et al. / Inorganica Chimica Acta 358 (2005) 3417–3422
3419
[M ꢁ Cl]+. Anal. Calc.: C, 61.67; H, 5.17. Found: C,
d = 151.91(CO), 138.32(Ar), 134.01(Ar), 132.35(Ar),
61.89; H, 5.26%.
131.36(Ar),
130.83(Ar),
129.97(Ar),
128.12(Ar),
21.32(CH3), 19.59(2 CH ). 31P (81 MHz, CDCl3):
*
3
2.3.2. trans-[PdCl2{PPh2O(2,6-Ph2C6H3)}2] (4)
1
d = 122.00(d). ESI-MS (m/z): 771.17, [M ꢁ Cl]+;
743.18, [M ꢁ Cl ꢁ CO]+. Anal. Calc.: C, 63.99; H,
5.25. Found: C, 63.72; H, 5.31%.
(80% yield) H (400 MHz, CDCl3): d = 7.62–7.58(m,
8H), 7.53–7.47(m, 8H), 7.45–7.38(m, 4H), 7.37–7.34(m,
4H), 7.31(d, J = 4.4 Hz, 4H), 7.27–7.00(m, 18H). 13C
(CDCl3, 100 MHz): d = 138.96(Ar), 137.98(Ar),
2.3.4. trans-[Rh(CO)Cl{PPh2O(2,6-Ph2C6H3)}2] (6)
(79% yield) 1H (200 MHz, CDCl3): d = 7.37(d,
J = 7 Hz, 8H), 7.26–7.16(m, 18H), 7.15–7.09(m, 12H),
134.12(Ar),
130.75(Ar),
130.37(Ar),
129.76(Ar),
129.26(Ar),
129.15(Ar),
128.59(Ar),
128.07(Ar),
127.43v, 121.11(Ar). 31P (81 MHz, CDCl3): d =
106.62(s). ESI-MS (m/z): 571.9, [M ꢁ Cl ꢁ PPh2O-
(C6H5)2(C6H3)]+. Anal. Calc.: C, 69.41; H, 4.47. Found:
C, 69.19; H, 4.56%.
7.08–7.02(m,
d = 150.02(CO), 139.66(Ar), 137.34(Ar), 133.21(Ar),
133.13(Ar), 133.06(Ar), 131.26(Ar), 130.02(Ar),
8H).
13C
(CDCl3,
100 MHz):
128.26(Ar), 127.52(Ar), 127.45(Ar), 127.40(Ar). 31P
(81 MHz, CDCl3): d = 128.37 (d). ESI-MS (m/z):
914.9, [M ꢁ (C6H5) ꢁ Cl + H]+. Anal. Calc.: C, 71.32;
H, 4.51. Found: C, 71.20; H, 4.59%.
2.3.3. trans-[Rh(CO)Cl{PPh2O(2,4,6-Me3C6H2)}2]
(5)
1
(82% yield) H (200 MHz, CDCl3): d = 7.80–7.62(m,
8H Ar), 7.42–7.29(m, 12H Ar), 6.89(s, 4H), 2.38(s, 6H
2.4. X-ray crystallographic study
Me), 2.14(s, 12H Me). 13C (CDCl3, 100 MHz):
Data were collected using a Stoe Imaging Plate Dif-
fractometer System (Stoe & Cie, 1995) equipped with a
one-circle u goniometer and a graphite-monochromator
Table 1
Crystallographic data for the structures of complexes 3ÆCHCl3 and
5ÆCHCl3
˚
(Mo Ka radiation, k = 0.71073 A). 200 exposures (3 min
per exposure) were obtained at an image plate distance
of 70 mm with 0 < u < 200ꢁ and with the crystal oscillat-
ing through 1ꢁ in u. The resolution was Dmin–Dmax
3ÆCHCl3
5ÆCHCl3
Chemical formula
Formula weight
Crystal color and shape
Crystal size
C43H43Cl5O2P2Pd
937.36
C44H43Cl4O3P2Rh
926.43
˚
12.45–0.81 A.
yellow plate
0.50 · 0.50 · 0.10
monoclinic
P21/c
yellow plate
0.40 · 0.20 · 0.20
monoclinic
P21/c
Crystal system
Space group
Table 2
˚
Selected bond lengths (A) and angles (ꢁ) in complex 3ÆCHCl3
˚
a (A)
18.865(2)
10.9145(7)
21.046(2)
101.718(13)
4243.1(7)
4
17.1373(12)
10.6328(5)
24.4935(18)
97.540(8)
4424.6(5)
4
Interatomic distances
˚
b (A)
Pd(1)–P(1)
Pd(1)–P(2)
Pd(1)–Cl(1)
Pd(1)–Cl(2)
P(1)–O(1)
P(2)–O(2)
P(1)–C(1)
P(1)–C(7)
P(2)–C(22)
P(2)–C(28)
O(1)–C(13)
O(2)–C(34)
2.3268(12)
2.3098(12)
2.3021(13)
2.2997(12)
1.615(3)
1.616(3)
1.820(4)
1.820(5)
1.814(4)
1.823(5)
1.416(5)
1.419(5)
˚
c (A)
b (ꢁ)
3
˚
V (A )
Z
Dcalc (g cmꢁ3
)
1.467
0.863
1.391
0.737
l(Mo Ka) (mmꢁ1
Temperature (K)
F(000)
)
173(2)
1912
173(2)
1896
Scan range (ꢁ)
Cell refinement
2.28 < h < 25.90
8000
2.28 < h < 25.90
8000
parameters reflections
Reflections measured
Independent reflections
Reflections observed
[I > 2r(I)]
32178
8115
4689
34021
8569
6211
Bond angles
P(1)–Pd(1)–P(2)
Cl(1)–Pd(1)–Cl(2)
P(1)–Pd(1)–Cl(1)
P(1)–Pd(1)–Cl(2)
P(2)–Pd(1)–Cl(1)
P(2)–Pd(1)–Cl(2)
C(1)–P(1)–Pd(1)
C(7)–P(1)–Pd(1)
C(22)–P(2)–Pd(1)
C(28)–P(2)–Pd(1)
O(1)–P(1)–Pd(1)
O(2)–P(2)–Pd(1)
C(13)–O(1)–P(1)
C(34)–O(2)–P(2)
175.48(5)
179.09(4)
93.32(4)
87.59(4)
Rint
0.1048
0.0423
Final R indices [I > 2r(I)]
R1 = 0.0472,
wR2a = 0.1113
R1 = 0.0885,
wR2a = 0.1221
0.882
R1 = 0.0365,
wR2a = 0.0893
R1 = 0.0548,
wR2a = 0.0941
0.988
91.09(4)
88.00(4)
R indices (all data)
120.90(16)
113.00(16)
113.43(16)
118.60(14)
114.89(11)
115.39(11)
125.8(3)
Goodness-of-fit
Residual density:
0.712, ꢁ0.986
0.728, ꢁ0.664
maximuꢁm3, minimum
˚
Dq (e A
)
P
2
a
Structure
2 1=2
was
refined
on
F 2o : wR2 ¼ ½ ½wðF 2o ꢁ F c2Þ ꢂ=
P
P
2
wðF o2Þ ꢂ ; where wꢁ1 ¼ ½ ðF o2Þ þ ðaPÞ þ bPꢂ and P ¼ ½maxðF 2o;
128.6(3)
0Þ þ 2F 2cꢂ=3.

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L. Chahen et al. / Inorganica Chimica Acta 358 (2005) 3417–3422
Table 3
out with rigorous exclusion of air, in order to avoid oxi-
dation of the phosphinite groups.
˚
Selected bond lengths (A) and angles (ꢁ) in complex 5ÆCHCl3
Interatomic distances
Ph2PCl + HOR ! Ph2POR + HCl
ð1Þ
Rh(1)–P(1)
Rh(1)–P(2)
Rh(1)–Cl(1)
Rh(1)–C(43)
C(43)–O(3)
P(1)–O(1)
2.3103(8)
2.3202(7)
2.3411(8)
1.834(4)
1.105(4)
1.631(2)
1.631(2)
1.808(3)
1.823(3)
1.817(3)
1.821(3)
1.412(4)
1.416(3)
The phosphinite 1 is a very air-sensitive oil of light
yellow color, while 2 is a slightly air-sensitive white so-
lid. Both compounds have been characterized by correct
NMR (1H, 13C, 31P) and mass-spectroscopic data as well
as by satisfactory elemental analysis data.
The palladium phosphinite complexes are obtained by
reacting [PdCl2(cod)] (cod = 1,5-cyclooctadiene) with the
ligands 1 or 2 in methylene chloride at room temperature
(Eq. 2). The two complexes [PdCl2(1)2] (3) and
[PdCl2(2)2] (4) are isolated as yellow powders (Scheme 3).
P(2)–O(2)
P(1)–C(1)
P(1)–C(7)
P(2)–C(22)
P(2)–C(28)
O(1)–C(13)
O(2)–C(34)
Bond angles
PdCl2(cod) + 2 ROPPh2 ! [PdCl2fROPPh2g2]2 + cod
ð2Þ
Both compounds have been characterized by correct
NMR (1H, 13C, 31P) and mass-spectroscopic data as well
as by satisfactory elemental analysis data.
Yellow crystals of 3ÆCHCl3, suitable for single-
crystal X-ray structure analysis were obtained by slow
evaporation of a concentrated chloroform solution of
the complex during several days at room temperature.
This compound crystallized in the monoclinic P21/c
space group. The molecular formula of this compound
is [PdCl2{PPh2O(2,4,6-Me3C6H2)}2]ÆCHCl3. The molec-
ular structure of 3 is shown in Fig. 1. The Pd metal cen-
ter is tetracoordinated by the chelating phosphorus
P(1)–Rh(1)–P(2)
Cl(1)–Rh(1)–C(43)
O(3)–C(43)–Rh(1)
P(1)–Rh(1)–Cl(1)
P(1)–Rh(1)–C(43)
P(2)–Rh(1)–Cl(1)
P(2)–Rh(1)–C(43)
C(1)–P(1)–Rh(1)
C(7)–P(1)–Rh(1)
C(22)–P(2)–Rh(1)
C(28)–P(2)–Rh(1)
O(1)–P(1)–Rh(1)
O(2)–P(2)–Rh(1)
C(13)–O(1)–P(1)
C(34)–O(2)–P(2)
177.49(3)
179.58(11)
179.9(4)
91.27(3)
88.92(10)
90.85(3)
88.95(10)
119.53(10)
115.52(10)
113.52(10)
120.51(9)
115.61(8)
115.84(7)
123.43(19)
122.21(17)
The structure was solved by direct methods using the
program SHELXS-97 [9] and refined by full matrix least
squares on F2 with SHELXL-97 [10]. The hydrogen atoms
were included in calculated positions and treated as
riding atoms using SHELXL-97 default parameters. All
non-hydrogen atoms were refined anisotropically. An
empirical absorption correction was applied for the
complex 3 using DIFABS (PLATON-03 [11], Tmin = 0.300,
Tmax = 0.740).
Crystallographic details are given in Table 1, and sig-
nificant bond lengths and bond angles are listed in
Table 2 (3) and Table 3 (5). The figures were drawn with
ORTEP [12].
Scheme 2.
3. Results and discussion
The new aryl phosphinites PPh2OR (R = 2,4,6-
Me3C6H2, 1; R = 2,6-Ph2C6H3, 2) (Scheme 2) are acces-
sible according to a general method reported by Bedford
[4], using chlorodiphenylphosphine and the correspond-
ing phenol (Eq. 1). The nucleophilic substitution reac-
tion with elimination of HCl takes place in toluene at
80 ꢁC, provided that the acid eliminated is trapped by
NEt3 to give the salt [NEt3H]Cl, insoluble in toluene.
The synthesis isolation of the products must be carried
Scheme 3.

L. Chahen et al. / Inorganica Chimica Acta 358 (2005) 3417–3422
3421
[RhCl(CO){PPh2O(C6H5)}2]
and
[RhCl(CO){2,20-
(PPh2O)2 C12H8}], the molecular structures of which,
however, are not known [14].
1/2 [Rh2Cl2(CO)4] +2 ROPPh2
! [RhCl(CO)(ROPPh2)2] + CO
ð3Þ
Both compounds 5 and 6 have been characterized by
correct NMR (1H, 13C, 31P) and mass-spectroscopic
data as well as by satisfactory elemental analysis data.
Yellow crystals of 5ÆCHCl3, suitable for single-
crystal X-ray structure analysis were obtained by leaving
a concentrated chloroform solution of the complex
standing several days at room temperature. This com-
pound also crystallized in the monoclinic P21/c space
group. The molecular formula of this compound is
[RhCl(CO){PPh2O(2,4,6-Me3C6H2)}2]ÆCHCl3. The mo-
lecular structure of 5 is shown in Fig. 2. The structure of
Fig. 1. Molecular structure of 3 with thermal ellipsoids at 50%
probability. Hydrogen atoms are omitted for clarity.
ligand and two chloride anions in a typical trans square-
˚
plane geometry. The Pd is displaced by 0.0111(7) A out
of the square-plane. The two oxo-mesityl arms, situated
on the both sides of the P(1)–Pd(1)–P(2) axis, fall back
towards the Pd cation. However, we note that the two
rings are not parallel (the angle between the two mesityl
rings is 17.3(2)ꢁ). Significant bond lengths and bond an-
gles are listed in Table 2. The Pd–P and Pd–Cl distances
are similar to those of the only example of trans Pd com-
plex containing phosphinite ligands [13].
The rhodium phosphinite complexes 5 and 6 (Scheme
4) are accessible from [Rh2(CO)4Cl2] and the ligands 1
and 2, the reaction taking place in methylene chloride
within 24 h (Eq. 3). The two complexes 5 and 6 are ob-
tained as yellow powders. To our knowledge, there are
only two other mononuclear chlorocarbonyl rhodium
complexes containing aryl-diphenylphosphinite ligands,
Fig. 2. Molecular structure of 5 with thermal ellipsoids at 50%
probability. Hydrogen atoms are omitted for clarity.
Scheme 4.

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L. Chahen et al. / Inorganica Chimica Acta 358 (2005) 3417–3422
5 is similar to that of 3 with a Rh metal center tetraco-
ordinated by the chelating phosphorus ligand, a chloride
anion and a carbonyl group in a typical trans square-
1EZ, UK; fax: +44 1223 336 033; e-mail: deposit@
ccdc.cam.ac.uk].
˚
plane geometry. The Rh is displaced by 0.0169(10) A
References
out of the square-plane. Like in the structure of 3, the
ligand conformation is the same with the two oxo-
mesityl arms, situated on the both sides of the P(1)–
Rh(1)–P(2) axis, falling back towards the Rh cation.
The two rings are not parallel either, but the angle be-
tween the two mesityl rings is smaller (4.77(12)ꢁ). Signif-
icant bond lengths and bond angles are listed in Table 3.
[1] Boy Cornils, Wolfgang A. Herrmann, Applied Homogeneous
Catalysis with Organometallic Compounds, Wiley-VCH, Wein-
heim, 1996, p. 712.
[2] R.B. Bedford, C.S.J. Cazin, D. Holder, Coord. Chem. Rev. 248
(2004) 2283.
¨
[3] M. Beller, H. Fischer, W.A. Herrmann, K. Ofele, C. Brossmer,
Angew. Chem. Int. Ed. 34 (1995) 1848.
[4] R.B. Bedford, S.L. Hazelwood, M.E. Limmert, Organometallics
22 (2003) 1364.
˚
The Rh–CO distance of 1.834(4) A in 5 is similar to the
one in [Rh(CO)Cl{PPh2ORf}]2[15], the only example of
trans Rh complex containing phosphinite ligands, while
[5] R.B. Bedford, S.L. Hazelwood, P.N. Horton, M.B. Hursthouse,
Dalton Ttrans. (2003) 4164.
˚
the C–O distance (1.105(4) A) is slightly shorter by
˚
0.018 A, consistent with a slightly weaker Rh–CO inter-
action in 5. The Rh–P and Rh–Cl distances in 5 are
similar to those of this complex.
[6] R.B. Bedford, Chem. Commun. (2003) 1787.
[7] A.M. Trzeciak, H. Bartosz-Bechowski, Z. Ciunik, K. Niesyty,
´
J.J. Ziolkowski, Can. J. Chem. 79 (2001) 752.
[8] M.E. van der Boom, S.-Y. Liou, Y. Ben-David, L.J.W. Shimon,
D. Milstein, J. Am. Chem. Soc. 120 (1998) 6531.
[9] G.M. Sheldrick, Acta Crystalogr. A46 (1990) 467.
[10] G.M. Sheldrick, SHELXL-97 Program for Crystal Structure Refine-
ment, University of Go¨ttingen, Germany, 1997.
4. Supplementary material
[11] A.L. Spek, J. Appl. Crystallogr. 36 (2003) 7.
CCDC-264731 (for 3ÆCHCl3) and CCDC-264732
(for 5ÆCHCl3) contain the supplementary crystallo-
graphic data for these structures. These data can be ob-
tained free of charge at www.ccdc.cam.ac.uk/conts/
retrieving.html [or from the Cambridge Crystallo-
graphic Data Center, 12 Union Road, Cambridge CB2
[12] L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565.
[13] P. Faidherbe, C. Wieser, D. Matt, A. Harriman, A. De Cian, J.
Fischer, Eur. J. Inorg. Chem. (1998) 451.
[14] S.C. van der Slot, J. Duran, J. Luten, P.C.J. Kamer, P.W.N.M.
van Leeuwen, Organometallics 21 (2002) 3873.
[15] C.M. Haar, J. Huang, S.P. Nolan, J.L. Petersen, Organometallics
17 (1998) 5018.