Some phosphinite complexes of Rh and Ir, their intramolecular reactivity and DFT calculations about their application in biphenyl metathesis

Article abstract of DOI:10.1016/j.jorganchem.2007.09.035

Biphen(OPR₂) (with R: Ph, iPr, Cy) is reacted with [Rh(COE)₂Cl]₂. The corresponding μ-chloro-bridged dimers are received. An X-ray analysis of [Biphen(OPCy₂)RhCl]₂ is included. This compound shows a d

Full text of DOI:10.1016/j.jorganchem.2007.09.035

Available online at www.sciencedirect.com
Journal of Organometallic Chemistry 693 (2008) 874–893
www.elsevier.com/locate/jorganchem
Some phosphinite complexes of Rh and Ir, their
intramolecular reactivity and DFT calculations about their
application in biphenyl metathesis
*
Klaus Ruhland , Peter Gigler, Eberhardt Herdtweck
TU Mu¨nchen, Lehrstuhl fu¨r Anorganische Chemie, Lichtenbergstr. 4, D-85748 Garching, Germany
Received 13 August 2007; received in revised form 26 September 2007; accepted 26 September 2007
Available online 18 October 2007
Abstract
Biphen(OPR2) (with R: Ph, iPr, Cy) is reacted with [Rh(COE)2Cl]2. The corresponding l-chloro-bridged dimers are received. An
X-ray analysis of [Biphen(OPCy2)RhCl]2 is included. This compound shows a dynamic behaviour in solution, ascribed to a mono-
mer/dimer equilibrium. The difference of the Biphen ligands to Milsteins PCP pincer-type ligand is shown. A catalytic cycle for biphenyl
metathesis containing the coupling of oxidative addition and reductive elimination of the bridging C–C single bond in the biphenyl frag-
ment using RhI/III complexes and the concept of chelating assistance was calculated using DFT (B3PW91/LANL2DZ). According to the
calculations the activation energy of the oxidative addition is about 30 kcal/mol and for the reductive elimination about 19 kcal/mol. The
fac–RhIII complex is by far the most stable compound, but the formation of it is kinetically strongly disfavoured. Pre-catalysts
(COD)M(Ph-O-PR2) (M: Rh, Ir) were synthesized by pre-coordinating the phosphinite to the metal (X-ray structures of four such com-
pounds included) followed by treatment with 2 equiv. of sec. BuLi (X-ray structures of two such compounds included). In case of Ir this
synthesis is complicated by C–H activation (X-ray structure of (COD)Ir(H)(Cl)(2-Br-phenyl-O-(diisopropylphosphinite)) included) and
fast oxidative addition of the Ph-C–Halide bond. For (COD)Ir(H)(Cl)(2-phenyl-O-(diisopropylphosphinite)) the C–H activation is
reversible and thermodynamic parameters for the ring closure reaction were determined by VT-NMR measurement
(DH = ꢀ21.1 0.5 kJ/mol, DS = ꢀ62.8 1.7 J/(mol K)). The pre-catalysts were reacted with Biphen(OPR2) to enter the calculated
catalytic cycle. With Rh as center metal this reaction works out cleanly to give new complexes with the three P-atoms coordinated to
one Rh center. No hemi-labile character was found for these P-donors even at 105 ꢀC in toluene. If (COD)Rh(2-phenyl-O-(dii-
sopropylphosphinite)) is reacted with 2 equiv. of 2-iodo-phenyl-O-(diisopropylphosphinite) oxidative addition of one C–Iodo bond is
observed and the corresponding mer–RhIII complex is received. Upon treatment with 2 equiv. of sec. BuLi the resulting product is(Bi-
phen(OPiPr2))RhI(2-phenyl-O-(diisopropylphosphinite)) rather than mer–RhIII(2-phenyl-O-(diisopropylphosphinite))3. Reaction of
[Rh(COD)Cl]2 with 3 equiv. of 2-bromo-phenyl-O-(diphenylphosphinite) shows a fast scrambling of the chlorine into all possible ortho
positions of the phenolate rings in the final RhIII reaction product.
ꢁ 2007 Elsevier B.V. All rights reserved.
Keywords: Group 9 complexes; Metathesis
1. Introduction
of this group show that the actual pathway of the reaction
is not via the cleavage of a C(sp3)–C(sp3) single bond but
rather by a combination of C–H activation, a/b-H elimina-
tion, olefin metathesis and insertion processes. This reac-
tion, although very important for oil chemistry in which
the molecules contain a lot of C–H bonds connected to
the C–C single bond under focus, cannot be transferred
to a possible metathesis between biphenyl fragments.
C–C single bond metathesis of alkanes has been success-
fully performed using immobilized group-5 and group-6
catalysts by the group of Basset [1]. Mechanistic studies
*
Corresponding author. Tel.: +49 89 289 13096; fax: +49 89 289 13473.
E-mail address: klaus.ruhland@ch.tum.de (K. Ruhland).
0022-328X/$ - see front matter ꢁ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.09.035

K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
875
a metathesis reaction, the bridging C–C single bond must
be broken meanwhile and reformed afterwards (Scheme 1).
We call this type of new reaction biphenyl metathesis. In
spite of the fact that for late transition metals in low oxida-
tion state (as for instance IrI) the oxidative addition of the
bridging C(sp2)–C(sp2) single bond, forming two C(sp2)–M
bonds, is expected to be thermodynamically favourable [2]
and the kinetic hindrance for it should be much less pro-
nounced than for alkane C(sp3)–C(sp3) single bonds, there
is by now no precedence for the activation or cleavage of a
non-strained biphenyl molecular fragment. The strained
biphenylene, though, has been activated and cleaved by
several groups [3]. On the other hand the through-breaking
work of Milstein and coworkers [4] showed that it is possi-
ble to cleave an aryl(sp2)-methyl(sp3) single bond by group
9 metal complexes and it demonstrated that in specific
cases this reaction is thermodynamically favoured if chelat-
ing assistance is applied.
Biphenyl Metathesis
Scheme 1.
R2P
R2P
O
1
X
X: O, CH2, OCH2
Y: H, Br, I, Rh
R: Ph, iPr, Cy
Y
1'
O
PR2
PhenY(XPR2)
Biphen(XPR2)
Scheme 2.
2. The difference to Milstein’s pincer-type ligands
Those are components of coal and lignin chemistry, two
sources for basic chemicals that might become more impor-
tant in the future. If in analogy to alkane metathesis biphe-
nyl molecular fragments are to be reorganized according to
In light of the fact that Crabtree and coworkers could
cleave one of the strained bridging C(sp2)–C(sp2) single
bonds in biphenylene using [Ir(COD)Cl]2 on the one
hand and that Milstein and coworkers could cleave the
P
P
P
P
Cl
P
P
P
P
Cl
P
P
Rh
Cl
Rh
Rh
Rh
Rh
Rh
P
Cl
P
(A)
R
Cl
Cl
(B)
(B)2
R
R
P
R
R
R
R
P
O
R
O
O
P
O
O
O
P
Cl
Rh
Rh
Rh
Rh
Cl
Cl
Cl
P
R
O
P
R
P
R
R
O
P
R
R
R
R
Scheme 3.

876
K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
Fig. 1. Picture of a molecule in the solid state for [Biphen(OPCy2)RhCl]2 and [Cy-1,2-CH2(OPPh2)RhCl]2. Hydrogens are omitted for clarity. Thermal
ellipsoids are drawn at the 50% probability level.
non-strained C(sp2)–C(sp3) bond in their group-9 pincer-
type complexes, we decided to apply a biphenyl ligand with
phosphinites in 1 and 10 position for chelating assistance to
RhI (Scheme 2).
In case of Biphen(OPCy2)RhCl the signal at 179 ppm is
decisively broadened at room temperature, indicating an
equilibrium between monomer and dimer. PPh3 is not per-
manently coordinated by this compound. In fact, the signal
for PPh3 in 31P NMR spectroscopy appears at the same
position as free PPh3, but it is broadened. The peak of
Biphen(OPCy2)RhCl at 179 ppm does not change signifi-
cantly if PPh3 is added. An X-ray structure of a molecule
in the solid state for Biphen(OPCy2)RhCl showed only
the l-Cl-bridged dimeric structure (Scheme 3, Fig. 1, Table
1). A reference structure of a similar dimer with less
sterically demanding (OPPh2) donors and a somewhat dif-
ferent but still comparable backbone (–CH2–Cy–CH2–) is
shown in Fig. 1. Selected structural data are listed in Table
Thus, [Rh(COE)2Cl]2 (COE: Cyclooctene) was reacted
with the Biphen(OPR2) ligands (R: Ph, iPr, Cy) in benzene
or dichloromethane at room temperature. 31P NMR spec-
troscopy for [Biphen(OPPh2)RhCl]2 showed two close
1
sharp doublets (d1 = 140.5 ppm, JRhP = 230.8 Hz, d2 =
1
139.5 ppm, JRhP = 231.6 Hz) in the ratio 3.75:1, which
we assign to the two possible configuration isomers of the
l-chloro-bridged dimer (B2, Scheme 3). This is confirmed
by the fact that the addition of 1 equiv. of PPh3 per Rh
gives [Biphen(OPPh2)](PPh3)RhCl with only one set of sig-
nals for each of the three P atoms (O–P1: 145.8 ppm ddd,
1. According to this, the Rh–Cl bond length in (B)2Cy
2
2
Cy
1JRhP = 216.0 Hz JPPcis = 27.7 Hz JPPcis = 35.7 Hz; O–
(2.42 A in (B)2 and 2.43 A in the reference structure) is
not elongated in comparison to the reference structure,
but the square planes of the two Rh centers are bent to
each other in contrast to the reference structure in which
all Rh, P and Cl atoms are in one and the same plane.
The signals of the phenyl-carbons in 13C NMR spectros-
copy for Biphen(OPCy2)RhCl are broadened, too, at room
temperature. A coupling of the bridging C-atoms to Rh or
P that would be an indicator for an interaction between
these carbons and the Rh center cannot be unequivocally
determined (this coupling is expected to be smaller than
10 Hz). The synthesis of the ligand Biphen(OPtBu2), with
the intention to support the dissociation of the dimer did
not work out in our hands.
˚
˚
P2: 131.2 ppm ddd JRhP = 176.4 Hz JPPcis = 27.7 Hz
1
2
2JPPtrans = 396.3 Hz; PPh3: 28.8 ppm ddd 1JRhP = 128.9 Hz
2JPPcis = 35.7 Hz JPPtrans = 396.3 Hz). A similar result is
2
obtained for Biphen(OPiPr2)RhCl (d1 = 179.7 ppm, d2 =
179.3 ppm, 1JRhP = 229.8 Hz both, ratio 1:1). The reaction
with PPh3 results in this case in an equilibrium mixture
between the two l-chloro-bridged dimers and free PPh3
on the one hand and the monomer with coordinated
PPh3 (ratio: dimer 2.1:monomer 1: free PPh3 2.7 at room
temperature; ratio does not change after 24 h; the P-atom
peaks for the PPh3-coordinated monomer are slightly
broadened) on the other hand.
We calculated the structures for the two possible
T-shape monomers (A) and (B) in Scheme 3 with
R = Cy using DFT (B3PW91/LANL2DZ). Pictures of
the calculated structures are included in Scheme 3. In
structure (A) an interaction of the biphenyl fragment
with the Rh center is found, but not as anticipated via
the bridging C–C single bond. Only one of the bridging
carbons takes part in this interaction; the second center
in the biphenyl fragment is the carbon of the same
phenyl ring that is connected to the oxo group. The
C–C bond between these two carbons is elongated
Table 1
Selected structural data for [Biphen(OPCy2)RhCl]2 and [Cy-1,2-CH2-
(OPPh2)RhCl]2
[Biphen(OPCy2)RhCl]2 [Cy-1,2-
CH2(OPPh2)RhCl]2
˚
Rh–P (A)
Rh–Cl (A)
Fold angle
along Cl–Cl (ꢀ)
Cl–Rh–Cl (ꢀ)
P–Rh–P (ꢀ)
2.1818(6)/2.1939(6)
2.4200(6)/2.4235(6)
46.45
2.1770(5)/2.1876(5)
2.4300(5)/2.4361(5)
0
˚
79.10(2)
91.83(2)
81.05(2)
89.43(2)

K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
877
R
R
P
R
P
R
R
O
O
P
O
O
R
O
Rh
O
Rh
Rh
Cl
P
O
R
R
R
PR2
P
R
R
O
P
R
P
R
R
Scheme 4.
˚
˚
(d(C1–C2) = 1.44 A, d(Rh–C1) = 2.46 A, d(Rh–C2) =
3. Results of the DFT calculations
˚
2.65 A). According to the calculations structure (B) is
more stable than (A) by 6.7 kcal/mol. Thus, it must be
concluded that even by forcing the dimer (B)2 to dissoci-
ate through steric pressure, the T-shape isomer with the
cis-connectivity of the P-donors is predominant, which
in turn does not show interactions of the biphenyl frag-
ment with the metal center. These first results point out
that our substrate-ligand is more flexible than the unique
Milstein-pincer-type ligand which does not allow for sta-
ble cis-complexes. To prevent the formation of a dimer
and to prefer (A) over (B) we used the strategy shown
in Scheme 4.
On the base of a mechanism including a reversible oxi-
dative addition/reductive elimination sequence via MI/MIII
metal centers we calculated the catalytic cycle shown in
Scheme 5 for the case of R = Me in Scheme 4 using Density
Functional Theory (B3PW91/LANL2DZ).
Some highlights concerning Scheme 5 and Fig. 2, which
contains the energy profile of Scheme 5, are to be pointed
out. First, the calculations indicate that there are two
four-coordinate RhI structures of similar energy, one of
them with square planar geometry 2a. The other one is tri-
gonal pyramidal 2a0. A C–H-agostic interaction is found
Scheme 5.

878
K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
E
(3#)
TS
(2b)
20.2 kcal/mol
TS
(3b)
(2#)
(2d)
(2e)
33.7 kcal/mol
(2a)
(2a‘)
(3a)
Fig. 2. Energy profile to Scheme 5.
we could not find a transition state (reasonable in energy)
leading to the fac–RhIII isomer, but we did find one leading
to the mer–RhIII complex (activation barrier for the oxida-
tive addition: 33.7 kcal/mol).
In the transition state 3# the distances of the two car-
bons that form new bonds to the metal center are not
equal, and, thus, no completely concerted reaction takes
place because of pseudo-Jahn-Teller effects in the d 8 start-
ing geometry and the d6 product geometry (Fig. 4).
Fig. 3. Picture of the calculated structures of 2d (left) and 3b0 (right),
demonstrating the Rh–O interaction in 3b0 and the absence of such kind of
interaction in 2d.
4. Synthesis of the pre-catalyst
The Rh-pre-catalysts in Scheme 5 can be synthesized by
pre-coordination of the 2-bromo-phenylphosphinite (quan-
titative reaction) and successive treatment with 2 equiv. of
sec. BuLi at ꢀ78 ꢀC in diethylether (60–90% yield) (Scheme
6).
for the T-shape complex 2e. Interactions between the
bridging oxo and the Rh center are found in (3b0) but
not in 2d (Fig. 3).
The fac–RhIII complex 3a is a thermodynamic sink in
the system and would be a trap for the catalytic cycle, in
contrast to the mer–RhIII isomer 3b. As jet, in this case
The 2-iodo derivative cannot be used because oxidative
addition to Rh takes place and the resulting complexes
decompose. Direct ortho-lithiation of the phosphinite
without pre-coordination to Rh is not possible because
the phosphinite rearranges to a 2-phosphino-phenolate.
The use of n-BuLi instead of sec. BuLi in the second step
leads to a considerable decrease in the yield. With PPh2
donor hands the ring closure reaction in the second step
did not always work. Fig. 5 shows pictures of a molecule
in the solid state determined by X-ray analysis for
D
D
D
Ph
Ph
Rh
Rh
Rh
Ph
D
D
D
not
not
not
(COD)Rh(Cl)(PhenBr(OPiPr2)) (1), (COD)Rh(PhenRh
-
(OPiPr2)) (2) and for (COD)Rh(PhenRh(CH2OPiPr2)) (3).
Table 2 contains selected structural data. As can be seen
in 2 the phenyl group plane is parallel to the square plane
around the Rh while in 3 these planes are perpendicular to
each other.
D
D
D
Rh
Rh
Rh
D
D
D
The synthesis of the analogous Ir-complexes is compli-
cated by C–H activation and the more facile oxidative
addition of a C–Halide bond by Ir in comparison to Rh
(Scheme 7).
Fig. 4. Geometrical development during the oxidative addition to the d8–
RhI center with T-shape geometry which changes to a square pyramid d6–
RhIII complex because of a pseudo-Jahn-Teller effect.

K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
879
R
P
X
R
R
P
R
R
R
P
Br
Cl
X
sec.-BuLi
-78°C
X
Rh
Rh
Rh
Rh
RT
Cl
Cl
Br
Scheme 6.
Fig. 5. Pictures of a molecule in the solid state for 1, 2 and 3. Hydrogens are omitted for clarity. Thermal ellipsoids are drawn at the 50% probability level.
If [(COD)IrCl]2 is treated with PhenBr(OPiPr2) exclu-
sively ortho-C–H activation of the ligand is observed in
contrast to the analogous Rh-complex. An X-ray analysis
for compound 4 in Scheme 7 could be obtained. A picture
of a molecule 4 in the solid state is shown in Fig. 6. Table 3
contains selected structural data.
The C–H activation can be prevented by substituting the
ortho-H by fluorine. In this case the coordination takes
place cleanly. An X-ray structure of a molecule in the solid
state could be obtained for compound 5 in Scheme 7 and a
picture of it is shown in Fig. 8 with some selected structural
data summarized in Table 4 which are compared to the
If [(COD)IrCl]2 is reacted with PhenH(OPiPr2) the C–H
activation process becomes reversible and both compounds
12 and 13 in Scheme 7 are observed. The thermodynamic
data for the reaction of the C–H activation in this case
were obtained by determining the amounts of both com-
pounds at different temperatures using 31P NMR spectros-
copy (DH = ꢀ21.1 0.5 kJ/mol and DS = ꢀ62.8 1.7 J/
(mol K) (12 ! 13)). The equilibrium is reached almost
instantaneously even at ꢀ30 ꢀC in CDCl3. Fig. 7 shows
the Van’t Hofft plot for this reaction.
analogous Rh compound 5Rh
.
With compound 5 the ring closure reaction using sec.
BuLi works without complications and compound 6 can
be received in 88% yield. A second way to overcome the
C–H activation is to extend the arm length of the added
phosphinite ligand. If a CH2-group is incorporated and
PhenBr(CH2OPiPr2) is used, the addition of the ligand to
[(COD)IrCl]2 is possible without any C–H activation. A
picture of a molecule in the solid state determined by
X-ray analysis of the resulting complex 10 is shown in
Fig. 8. Table 4 contains some selected structural data.
We added bromoform to this reaction to check out whether
Table 2
Selected structural data for 1, 2 and 3
Table 3
Selected structural data for 4
X: Cl or Ph(C)
1
2
3
˚
Rh–P (A)
2.2845(15)
2.362(2)
1.397(11)
1.358(12)
2.1297(6)/
2.127(6)
2.255(7)/
2.239(7)
89.37(6)
2.2314(11)
2.070(4)
1.365(7)
1.355(7)
2.205(5)/
2.188(5)
2.235(5)/
2.239(4)
79.26(11)
2.261(2)
2.070(5)
1.362(10)
1.360(8)
2.211(7)/
2.249(6)
2.217(7)/
2.252(6)
84.9(2)
˚
Ir–P (A)
2.263(2)
˚
Rh–X (A)
˚
˚
˚
˚
Ir–Cl (A)
2.516(2)
2.074(5)
1.382(12)
1.376(9)
2.304(7)/2.298(8)
2.309(6)/2.303(7)
80.70(15)
C@C trans to X (A)
C@C trans to P (A)
Rh–C trans to X (A)
˚
Ir–C(phenyl) (A)
C@C trans to phenyl (A)
C@C trans to P (A)
Ir–C trans to phenyl (A)
Ir–C trans to P (A)
P–Ir–Ph(C) (ꢀ)
˚
˚
˚
˚
Rh–C trans to P (A)
˚
P–Rh–X (ꢀ)

880
K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
Br
H(D)
Br
Ir
Br
Cl
P
RT
sec.-BuLi
-78°C
Ir
Ir
O
P
O
O
Ir
Br
P
Cl
O
(8)
(7)
P
(9)
(11)
P
Br
-78°C
O
Br
sec.-BuLi
-78°C
Br
O
O
P
P
O
Br
Br
Cl
Cl
Ir
Cl
H
Br
Ir
Ir
P
Ir
O
P
(10)
Cl
P
O
(4)
P
O
Br
F
F
F
H
Ir
Cl
P
F
Br
Ir
Cl
P
sec.-BuLi
-78 °C
O
P
O
Ir
Ir
O
Cl
O
(12)
(13)
P
F
(6)
(5)
Scheme 7.
support for a fast reversible C–H-activation can be found
by trapping the Ir–H, but no Ir–H/Br exchange was
observed. The cyclization in the second step works (com-
pound 11 in Scheme 7) in 68% yield. In the case of two bro-
mine atoms in ortho position of the ligand’s phenyl ring
(2,6-Br-phenyl-O-(diisopropylphosphinite)) a slow oxida-
tive addition is observed at room temperature (first order
evaluation k25 ꢀC = 0.0037 minꢀ1, product consists of four
isomers (compound 8 in Scheme 7)). At 60 ꢀC after
30 min the oxidative addition is quantitative. If the iPr-sub-
stituents at the phosphorous atom are exchanged by
Ph-substituents 90 min are required for a quantitative oxi-
dative addition at 60 ꢀC. If the addition of the 2,6-dibromo
ligands is performed at ꢀ78 ꢀC followed by direct cycliza-
tion with 4 equiv. of sec. BuLi, compound 9 in Scheme 7
is received and if this reaction is quenched with D2O
instead of H2O, 66% of the ortho protons are found to be
deuterated.
5. Entrance into the catalytic cycle
To enter the catalytic cycle of Scheme 5, 2 was reacted
with Biphen(OPPh2). This reaction takes place quantita-
tively and within minutes (at most) at room temperature
to give complex 14 (in contrast, the Ir complexes 6, 9 and
11 do not readily exchange the COD even at elevated tem-
perature). Free (and only free) COD is detected by 1H
NMR spectroscopy. In the presence of the new complex
the 1,5-COD is isomerized within days at room tempera-
ture in toluene–d8 to give 1,4-COD and finally 1,3-COD.
The 31P NMR spectrum shows three ddd groups of peaks
for the new complex indicating that now three P-atoms
are coordinated at one Rh center (Fig. 9).
2
The JPP coupling constants unequivocally prove a
T-shape orientation of the three P atoms to each other
(two ct couplings combined with one cc coupling). The val-
1
ues of the JRhP coupling constants (all of them are deci-
sively larger than 100 Hz) support the oxidation state I
for the Rh center, although this diagnostic criterion is
not unequivocal. From these findings the calculated struc-
ture 2a0 of Scheme 5 can be excluded since in this structure
no T-shape geometry for the three P-atoms is found (the
angle between the P-atoms is almost 120ꢀ). No line-broad-
ening or other indicators of a dynamic behaviour could be
Fig. 6. Picture of a molecule in the solid state for 4. Hydrogens are
omitted for clarity. Thermal ellipsoids are drawn at the 50% probability
level.

K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
881
1/T [1/K]
0
0.003
-0.5
0.0032
0.0034
0.0036
0.0038
0.004
0.0042
-1
-1.5
-2
y = -2546.4x + 7.5581
R2 = 0.9922
-2.5
-3
-3.5
Fig. 7. Van’t Hofft plot for the reaction 12 ! 13.
detected by H or 31P NMR spectroscopy up to 105 ꢀC in
toluene–d8. Thus, no hemi-labile character is found for the
ligand constellation of 14. No hemi-labile behaviour is
induced if the iPr-rests at the P donor in 14 are exchanged
for Cy or if the spacer between the phenyl group and the P-
donor is extended to CH2–O (tBu rests can be introduced
into the mono-phosphinite ligand by refluxing the phenol
with (tBu)2PCl in acetonitrile for 10 days but the coordina-
tion of this ligand to [Rh(COD)Cl]2 is not clean and leads
to a mixture of products containing unreacted starting
material as well as free COD). 14 can be synthesized alter-
natively by starting with [Biphen(OPPh2)RhCl]2 (although
with decisively lower yield in the last step).
The coupling constants as well as the quite different
chemical shifts of the three P atoms in 15 are listed in
Fig. 11. The P atom with the signal at about 175 ppm
shows the expected values for a simple T-shape structure
(one 2Jppc and one 2JPPt coupling) in a RhI complex (1JRhP
coupling decisively larger than 100 Hz). In contrast, the
other two P atoms show peculiarities that are not consis-
1
2
tent with a T-shape geometry. The JPP coupling constant
between them (100 Hz) points towards an P–Rh–P angle
1
decisively larger than 90ꢀ. Also, the JRhP coupling con-
stant of the signal at 118 ppm is unusually small for RhI.
We propose therefore a distorted structure for 15 (similar
to 2a0 in Scheme 5 but not equal to it) rather than one
showing a square planar geometry around Rh (Fig. 11).
This also explains the large differences in the chemical
shifts of the three P atoms. As can be seen from Fig. 11
no evidence (through line broadening) for a hemi-labile
behaviour is found in this compound (even at 105 ꢀC in tol-
uene–d8).
In light of the results collected with [Biphen(OPiPr2)-
RhCl]2 and PPh3 we reacted 2 with Biphen(OPiPr2)
(Fig. 10). The ligand exchange reaction takes place,
although very slowly at room temperature. Even on heat-
ing to 60 ꢀC the complete reaction takes 2 weeks. Raising
the temperature above 60 ꢀC leads to a decomposition of
the complex indicated by a signal in 31P NMR spectros-
copy at about 50 ppm which appears as one single peak.
To synthesize compounds 3 of Scheme 5 in order to get
insight into the RhIII chemistry of the anticipated catalytic
Fig. 8. Pictures of a molecule in the solid state for 5 and 10. Hydrogens are omitted for clarity. Thermal ellipsoids are drawn at the 50% probability level.

882
K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
Table 4
cycle we used the strategy shown in Fig. 10, pathway (B).
Heating 2 in toluene–d8 at 100 ꢀC for 5 h with 2 equiv. of
PhenIodo(OPiPr2) results in the meridional RhIII compound
Selected structural data for 5, 5Rh and 10
M: Rh or Ir
5
5Rh
2.282(2)
10
2.286(2)
1
16. The RhIII character is proven by the small JRhP
˚
M–P (A)
2.282(2)
2.360(2)
1.390(15)
1.366(15)
2.107(8)/
2.123(9)
2.228(10)/
2.195(10)
˚
M–Cl (A)
C@C trans to Cl (A)
C@C trans to P (A)
M–C trans to Cl (A)
2.369(2)
1.371(12)
1.366(13)
2.134(8)/
2.122(6)
2.240(8)/
2.240(8)
89.64(6)
2.359(2)
1.419(15)
1.365(15)
2.132(10)/
2.113(9)
2.227(9)/
2.202(8)
90.87(8)
constants found (Fig. 12). The meridional geometry can
˚
˚
˚
2
be unequivocally deduced by the JPP coupling constants.
If compound 16 is reacted with 2 equiv. of sec. BuLi the
isolated product is compound 15 and not the mer–RhIII
complex. This is in accordance with the results of the
calculations presented in Fig. 3, which indicate that the
mer–RhIII is much less stable than 15. Also the activation
˚
M–C trans to P (A)
P–M–Cl (ꢀ)
90.62(7)
δ =138.4 ppm
1JRhP=140.7 Hz
2JPPc=19.8 Hz
2JPPc=57.5 Hz
Ph
δ =189.9 ppm
1JRhP=168.4 Hz
2JPPc=19.8 Hz
2JPPt=340.9 Hz
O
Ph
P
P
O
Rh
O
P
Ph
Ph
δ =129.5 ppm
1JRhP=170.4 Hz
2JPPc=57.5 Hz
2JPPt=340.9 Hz
(14)
195
190
185
180
175
170
165
160
155
150
145
140
135
130
125
(ppm)
Fig. 9. Excerpt of the 31P NMR spectrum for the product of the reaction of 2 with Biphen(OPPh2) showing the three groups of signals for the three P
atoms bound to Rh.
i-Pr
P
i-Pr
i-Pr
i-Pr
Rh
O
slow
P
O
O
+
Rh
(15)
O
O
P
P
P
O
P
i-Pr
i-Pr
i-Pr
i-Pr
sec. BuLi
-78 C to RT
i-Pr
i-Pr
i-Pr
i-Pr
P
p
i-Pr
O
I
i-Pr
(16)
O
O
°
5h 100 C
P
Rh
I
+
2
Rh
O
P
O
i-Pr
P
I
i-Pr
mer-Isomer is major product
Fig. 10. Reactions involving ligands with R = iPr exclusively.

K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
883
δ=144.3 ppm
1JRhP=165.4 Hz
2JPPc=21.7 Hz
2JPPc=98.5 Hz
δ= 174.7 ppm
1JRhP=159.6 Hz
2JPPc=21.7 Hz
2JPPt=401.8 Hz
i-Pr
i-Pr
P
P
P
P
O
O
O
O
Rh
P
i-Pr
P
i-Pr
δ=117.9 ppm
1JRhP=116.2 Hz
2JPPc=98.5 Hz
2JPPt=401.8 Hz
(15)
80
175
170
165 160
155
150 145
(ppm)
140
135
130
125
120
115
Fig. 11. Excerpt of the 31P NMR spectrum of 15.
of four very similar isomers is observed by 31P NMR spec-
troscopy. A VT NMR study in toluene–d8, allowing the
reaction to start at ꢀ80 ꢀC, proves that in the first place
δ= 109.6 ppm
1JRhP=100.5 Hz
2JPPc=17.7 Hz
2JPPc=59.1 Hz
δ= 83.2 ppm
1JRhP=76.8 Hz
2JPPc=59.1 Hz
2JPPt=474.7 Hz
RhI(PhenBr(OPPh2))3Clisformed(d1 = 133.9 ppm, 1JP1Rh
=
=
1
2
i-Pr
201.9 Hz; d2 = 123.9 ppm, JP2Rh = 162.9 Hz, JPP(cis)
i-Pr
i-Pr
i-Pr
36.7 Hz) which transforms extremely fast into four very
p
I
similar meridional RhIII isomers 17 at temperatures above
O
P
O
1
2
ꢀ40 ꢀC (1JP1Rh = 144.7 Hz, JP2Rh = 109.0 Hz, JPP(cis)
=
Rh
21 Hz, for all four isomers the same, ratio 1:1:0.65:0.73,
excess ligand does not change the ratio) (Fig. 13). No peaks
are found in the negative area up to ꢀ40 ppm in the proton
NMR spectrum. Re-cooling the sample from room temper-
ature to ꢀ50 ꢀC does not change the ratio or shape of the
peaks.
O
i-Pr
P
I
i-Pr
δ= 171.5 ppm
1JRhP=102.4 Hz
2JPPc=17.7 Hz
2JPPt=474.7 Hz
(16)
An X-ray structure of a molecule in the solid state
reveals the nature of the reaction product (Fig. 14).
A scrambling of the chlorines into the ortho positions
of the phenyl rings is unequivocally found. The finding
can be explained by a sequence of an oxidative addition
of a C–Br or a C–H bond followed by a reductive elimi-
nation of a C–Cl bond and another irreversible oxidative
addition of a C–Br bond. Considering just the elemental
steps, this is similar to the behaviour shown in Scheme
5 for the biphenyl metathesis. We admit that in spite of
this analogy there is still a considerable difference between
the two cases. The oxidative addition of the bridging phe-
nyl C–Ph single bond in a biphenyl fragment is much
more challenging than the oxidative addition of a phenyl
C–Br, C–H or C–Cl bond. Also, according to the X-ray
analysis there is a discrepancy between the expected and
found amounts of Br (3 vs. 2.5) and Cl (1 vs. 2.2) (the reac-
tion was done in benzene–d6 and the crystallization in ben-
zene–d6/pentane) which we cannot explain at the moment.
That we are not too far away from the truth, can be further
supported by the behaviour of RhI(PhenH(OPiPr2))3Cl. This
compound is stable at room temperature (d1 = 137.4 ppm,
Fig. 12. Data extracted from the 31P NMR spectrum of 16.
barrier of about 20 kcal/mol is in accordance with the
reductive elimination taking place at room temperature
(calculated k about 0.1 sꢀ1 for Methyl groups at the phos-
phorous). To prove that 15 is static rather than (degener-
ate) dynamic, we synthesized 15 with F atoms in 2- and
4-position of the ortho-metallated phenyl group and in a
sec. experiment with Cy rests instead of iPr at the P atom
connected to the ortho-metallated phenyl group via the
oxo. In both cases only one single isomer was detected by
31P NMR as well as 19F NMR spectroscopy.
6. Experimental support for the proposed principle
mechanism
That the equilibrium system used for the calculation in
Scheme 5 is a reasonable pathway, can be supported by
the following experimental finding: if [Rh(COD)Cl]2 is
reacted with 3 equiv. of PhenBr(OPPh2) at room tempera-
ture in CDCl3 or toluene–d8 the instantaneous formation

884
K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
Fig. 13. Excerpt of the 31P NMR spectrum at different temperatures for the reaction of [Rh(COD)Cl]2 with PhenBr(OPPh2).
Fig. 14. Picture of a molecule in the solid state for 17. Hydrogens are omitted for clarity. Thermal ellipsoids are drawn at the 50% probability level. On the
right-hand side are listed the occupancy ratios over the five positions.
1JP1Rh = 213.4 Hz, d2 = 128.5 ppm, 1JP2Rh = 162.9 Hz,
2JPP = 36.7 Hz). No peaks are found in the proton spec-
trum in the negative area up to ꢀ40 ppm. But by addition
of about 3 equiv. of bromoform two products very similar
to 17 are detected by 31P NMR spectroscopy, CH2Br2 is
observed and another RhI complex similar to the starting
compound is formed. We explain this finding as shown in
Scheme 8.
in general to be possible, although we admit that an
experimental proof is not provided in this paper. The pro-
posed mechanism involving an oxidative addition and a
reductive elimination of the bridging C–C single bond in
a biphenyl fragment at RhI/III complexes bearing a phenyl
ligand could be made plausible by DFT calculations. The
introducing synthetic work presented in this paper shows
that the proposed (pre)catalysts are available. The calcu-
lated activation barrier of 30 kcal/mol for the cleavage of
the bridging C–C single bond is still rather high, though.
At least, for a phenyl C–Halide rather than a phenyl C–
Ph bond the mechanism via oxidative addition and reduc-
tive elimination using RhI complexes with phosphinite
7. Conclusion
The calculated results presented in this paper indicate
that biphenyl metathesis as a yet unknown reaction seems

K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
885
Ph
Ph
Ph
Ph
O
O
Ph
Ph
O
O
Ph
P
Ph
Ph
P
Ph
P
P
H
H
P
O
O
Rh
O
Rh
P
Rh
P
H
Rh
P
Cl
O
P
Cl
Ph
Cl
Ph
Ph
Ph
Ph
P
Ph P Ph
Ph
O
Ph P Ph
Ph
Cl
Ph
Ph
O
O
Ph
O
CHBr
CHBr
CHBr
3
3
3
Ph
Ph
Ph
Ph
O
O
O
Ph
Ph
Ph
Ph
P
P
P
O
Br
P
Br
O
Rh
Rh
P
P
Br
Rh
P
Cl
Ph
O
Ph
P
Cl
Ph
Ph
Ph P Ph
Cl
Ph
Ph
Ph
O
Ph
O
O
Scheme 8.
ligands could be experimentally confirmed. But these two
processes (C–Halide vs. C–Ph) are admittedly still consid-
erably different.
9. Ligand synthesis
9.1. General procedure
8. Experimental section
0.31 mL (0.509 g; 2.94 mmol; 1 equiv.) of 2-bromo-phe-
nol are dissolved in 10 mL acetonitrile and 0.82 mL
(0.596 g; 5.89 mmol; 2 equiv.) of triethylamine are added.
Then 0.52 mL (0.497 g, 3.27 mmol; 1.1 equiv.) of chloro-
diisopropylphosphane are slowly added. A white precipitate
forms. The suspension is stirred for 1.5 h at room tempera-
ture. Then 40 mL of pentane are added and it is stirred for
another 20 min at room temperature. After this the pentane
phase is separated via canula and the pentane is removed in
vacuo to yield a slightly yellow oil (yield: 68%).
Manipulations and experiments were performed under
an argon atmosphere using standard Schlenk techniques
and/or in an argon-filled glove-box if not mentioned other-
wise. Diethylether, pentane, acetonitrile, dichloromethane,
toluene and THF were dried and degassed using a two-
column-drying system (MBraun) and stored under an
argon atmosphere over molecular sieves. CDCl3 and tolu-
ene–d8 were stored under argon over molecular sieves.
RhCl3 Hydrate, IrCl Hydrate, (NH ) IrCl and chlo-
*
*
3
4 2
6
rodicyclohexylphosphane were purchased from Strem
Chemicals and used without further manipulation.
1Z,5Z-cyclooctadiene (COD), cyclooctene (COE), chloro-
diphenylphosphane and 2,20-dihydroxbiphenyl were
purchased from VWR internatioanl, chlorodiisopropyl-
9.1.1. 2-Br-phenyl-O-(dicyclohexylphosphinite)
1H NMR (CDCl3, ppm): 1.2–2.0 (22H, unres. m, Cy-H),
3
3
6.80 (1H, t JHH = 7.2 Hz), 7.19 (1H, t JHH = 7.4 Hz),
3
3
7.25 (1H, d JHH = 7.2 Hz), 7.48 (1H, d JHH = 7.4 Hz);
13C NMR (CDCl3, ppm): 26.32 (s), 26.67 (d JCP = 7.3 Hz),
26.80 (s), 26.90 (d JCP = 6.6 Hz), 27.65 (d JCP = 17.6 Hz),
37.85 (d JCP = 17.6 Hz), 113.71 (s), 118.50 (d
JCP = 21.2 Hz), 122.23 (s), 128.18 (s), 133.06 (s), 155.96
(d, JCP = 10.2 Hz); 31P NMR (CDCl3, ppm): 148.7; EA
Calc. for C18H26OPBr: C, 58.55; H, 7.10; P, 8.39; Br,
21.64. Found: C, 58.77, 7.35; P, 8.22; Br, 21.12%.
phosphane,
2-bromo-phenol,
2,6-dibromophenol,
2-iodo-phenol, 2-bromo-benzylic alcohol, 2-bromo-4,6-
difluorophenol were purchased from Aldrich and sec.
Butyl-Lithium from Acros Organics and they were all used
without further purification. [(COD)RhCl]2, [(COE)2-
RhCl]2, [(COD)IrCl]2 and [(COE)2IrCl]2 were synthesized
according to the literature [5].
The NMR measurement was performed on a Bruker
9.1.2. 2-Br-phenyl-O-(diphenylphosphinite)
1H NMR (CDCl3, ppm): 6.90 (1H, t 3JHH = 7.4 Hz), 7.18
1
AMX400. H NMR (7.24 ppm, 400 MHz) and 13C NMR
3
(77.0 ppm, 100 MHz) spectra were referred to the CDCl3/
CHCl3 resonances, 31P NMR (161 MHz) to 85% H3PO4
as external standard, 19F NMR (376 MHz) to hexafluoro-
benzene (ꢀ162.9 ppm) as external standard.
(2H, t and d overlapp), 7.39 (6H, m), 7.53 (1H, d JHH
=
7.4 Hz), 7.67 (4H, m); 13C NMR (CDCl3, ppm): 114.67 (s),
119.0 (d JCP = 17.6 Hz), 123.57 (s), 128.39 (s), 128.50 (d
JCP = 7.3 Hz), 129.89 (s), 130.55 (d JCP = 23.4 Hz), 133.36

886
K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
3
(s), 140.51 (d JCP = 17.6 Hz), 153.90 (d JCP = 10.2 Hz);
31P NMR (CDCl3, ppm): 113.1; EA Calc. for C18H14OPBr:
C, 60.53; H, 3.95; P, 8.67. Found: C, 60.25; H, 4.04; P,
8.85%.
7.35 (6H, m), 7.66 (4H, m), 7.73 (1H, d JHH = 8.4 Hz);
13C NMR (CDCl3, ppm): 89.18 (d JCP = 2.2 Hz), 117.7
(d JCP = 19.8 Hz), 124 (s), 128.4 (d JCP = 7.3 Hz), 129.35
(s), 129.87 (s), 130.33 (s), 130.7 (d JCP = 22.7 Hz), 131.72
(d JCP = 24.9 Hz), 139.41 (s), 140.32 (d JCP = 17.6 Hz),
156.25 (d JCP = 9.5 Hz); 31P NMR (CDCl3, ppm): 113.2;
EA Calc. for C18H14OPI: C, 53.49; H, 3.49; P, 7.66. Found:
C, 53.27; H, 3.31; P, 7.85%.
9.1.3. 2-Br-benzyl-O-(diisopropylphosphinite)
3
1H NMR (CDCl3, ppm): 0.94 (3H, d JHH = 7.4 Hz),
3
3
0.98 (3H, d JHH = 7.4 Hz), 1.04 (3H, d JHH = 7.4 Hz),
3
3
1 (3H, d JHH = 7.4 Hz), 1.71 (2H, hept JHH = 7.4 Hz),
3
4.73 (2H, d JPH = 7.4 Hz), 7.06 (1H, t JHH = 7.4 Hz),
9.2. Complexation with bis-phosphinites
3
3
7.23 (1H, t JHH = 7.4 Hz), 7.43 (2H, d JHH = 7.4 Hz);
13C NMR (CDCl3, ppm): 17.25 (d JCP = 19.5 Hz), 17.83
(d JCP = 17.6 Hz), 28.28 (s), 73.48 (d JCP = 15.5 Hz),
127.89 (s), 129.55 (d JCP = 20.4 Hz), 133.36 (s), 138.51 (d
JCP = 10.6 Hz); 31P NMR (CDCl3, ppm): 155.6.
9.2.1. General procedure
58.3 mg (0.139 mmol; 1 equiv.) of Biphen(PiPr)2 and
50 mg (0.0695 mmol; 1 equiv. Rh) of [Rh(COE)2Cl]2 are
dissolved in 5 mL dichloromethane (orange solution) and
it was stirred over night at room temperature. The next
day the solvent was removed in vacuo and the residing
solid was dissolved in 2 mL of toluene which then was
removed in vacuo again. The residing yellow brown solid
was washed with 1 mL of pentane and dried in vacuo
(yield: 70 mg, 90%).
9.1.4. 2,6-Dibrom-phenyl-O-(diisopropylphosphinite)
3
1H NMR (CDCl3, ppm): 1.14 (6H, d JHH = 6.1 Hz),
1.18 (6H, d 3JHH = 6.1 Hz), 2.17 (2H, hept 3JHH = 6.1 Hz),
3
3
6.73 (1H, t JHH = 7.3 Hz), 7.45 (2H, d JHH = 7.3 Hz);
13C NMR (CDCl3, ppm): 17.53 (d JCP = 20.5 Hz), 17.65
(d JCP = 18.3 Hz), 29.95 (d JCP = 22.7 Hz), 116.79 (d
JCP = 2.2 Hz), 124.43 (s), 133.17 (s), 151.98 (s); 31P
NMR (CDCl3, ppm): 171.22; EA Calc. for C12H17OPBr2:
C, 39.16; H, 4.66; P, 8.42. Found: C, 39.08; H, 4.04; P,
8.85%.
9.2.1.1. [Biphen(OPiPr2)2RhCl]2. 1H NMR (CDCl3,
ppm): 0.87 (6H, br m), 1.11 (6H, br m), 1.39 (12H, m),
1.99 (2H, br m), 2.62 (2H, br m), 7.07 (2H, br t), 7.14
(2H, br d), 7.19 (2H, br d), 7.24 (2H, br t); 13C NMR
(CDCl3, ppm): 18.03 (s), 18.79 (d JCP = 3.9 Hz), 19.14
(s), 19.32 (s), 19.91 (s), 20.15 (s), 34.85 (m), 121.82 (br s),
9.1.5. 2-I-phenyl-O-(diisopropylphosphinite)
123.46 (s), 129.15 (d JCP = 9.9 Hz), 131.37 (d JCP
=
3
1H NMR (CDCl3, ppm): 1.01 (3H, d JHH = 7.4 Hz),
8.3 Hz), 131.78 (s), 131.84; 31P NMR (CDCl3, ppm):
179.3 (1JRhP = 229.8 Hz), 180.4 (1JRhP = 229.7 Hz); EA
Calc. for C24H36RhO2P2Cl2: C, 51.77; H, 6.52; P, 11.12.
Found: C, 51.32; H, 6.50; P, 11.82%.
3
3
1.07 (3H, d JHH = 7.4 Hz), 1.11 (3H, d JHH = 7.4 Hz),
1.15 (3H, d 3JHH = 7.4 Hz), 1.91 (2H, hept 3JHH = 7.4 Hz),
3
6.60 (1H, t JHH = 7.4 Hz), 7.27 (2H, d and t overlapp),
7.62 (1H, d JHH = 7.4 Hz); 13C NMR (CDCl3, ppm):
3
17.18 (d JCP = 8.0 Hz), 17.57 (d JCP = 19.8 Hz), 28.17
(d JCP = 17.6 Hz), 88.5 (s), 117.00 (d JCP = 22.0 Hz),
122.84 (s), 129.6 (s), 139.20 (s), 157.90 (d JCP = 8.8 Hz);
31P NMR (CDCl3, ppm): 153.5; EA Calc. for C12H18OPI:
C: 42.88; H, 5.40; P, 9.21. Found: C, 52.53; H, 5.21; P,
9.54%.
9.2.1.2. [Biphen(OPCy2)2RhCl]2. 1H NMR (CDCl3,
ppm): 1.0–2.4 (40H, m), 2.75 (4H, br s), 7.02 (1H, t
3
3JHH = 7.2 Hz), 7.09 (1H, t JHH = 7.2 Hz), 7.18 (4H, t
3
3JHH = 7.2 Hz), 7.35 (4H, d JHH = 7.2 Hz), 7.42 (4H, d
3
3JHH = 7.2 Hz), 7.48 (2H, d JHH = 7.2 Hz); 13C NMR
(CDCl3, ppm): 25.4–30.3 (several br s), 45.72 (br m),
46.51 (br m), 117.82 (s), 121.99 (s), 123.34 (s), 128.92
(s)130.25 (s), 131.82 (br m), 132.22 (s), 154.62 (br d,
JCP = 11.6 Hz), 155.14 (s); 31P NMR (CDCl3, ppm): 180
(br s).
9.1.6. 2-Br-phenyl-O-(diisopropylphosphinite)
3
1H NMR (CDCl3, ppm): 0.95 (6H, dd JHH = 7.4 Hz
3
3
3JPH = 15.9 Hz), 1.15 (6H, dd JHH = 7.4 Hz JPH
=
3
3
11.0 Hz), 1.79 (2H, dhept JHH = 7.4 Hz JPH = 15.9 Hz),
3
3
6.46 (1H, t JHH = 7.4 Hz), 7.38 (2H, d JHH = 9.8 Hz),
9.2.1.3. Crystal-structure analysis of [Biphen(OPCy2)2-
RhCl]2. C72H104Cl2O4P4Rh2 Æ 4(C6D6),
7.43 (1H, dd JHH = 8.6 Hz JHH = 3.7 Hz); 13C NMR
Mr = 1770.63,
3
4
(CDCl3, ppm): 17.08 (d JCP = 12.9 Hz), 17.53 (d JCP
=
yellow fragment (0.08 · 0.12 · 0.19 mm3), monoclinic, I2/
30.6 Hz), 28.52 (d JCP = 30.6 Hz), 114.18 (s), 118.58 (s),
118.79 (s), 122.65 (s), 133.57 (s), 156.25 (d JCP = 8.8 Hz);
31P NMR (CDCl3, ppm): 152.7; EA Calc. for C12H18OPBr:
C, 49.85; H, 6.27; Br, 27.63. Found: C, 50.42; H, 6.72; Br,
27.24%.
a (No.: 15), a = 28.5238(3), b = 10.5768(1), c = 29.6343(3)
3
˚
˚
A, b = 101.912(1)ꢀ, V = 8747.9(2) A , Z = 4, dcalc = 1.344
g cmꢀ3, F000 = 3680, l = 0.562 mmꢀ1. Preliminary exami-
nation and data collection were carried out on an area
diffraction system (Xcaliburꢂ3, j-CCD, OXFORD DIF-
FRACTIONS) and graphite monochromated Mo Ka
˚
9.1.7. 2-I-phenyl-O-(diphenylphosphinite)
radiation (k = 0.71073 A; sealed tube). Data collection
3
1H NMR (CDCl3, ppm): 6.70 (1H, t JHH = 7.2 Hz),
were performed at 150 K within the
H range of
3
3
7.07 (1H, d JHH = 8.4 Hz), 7.16 (1H, t JHH = 7.2 Hz),
2.81ꢀ < H < 25.36ꢀ. After merging (Rsig = 0.0135), 7991

K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
887
[6792: Io > 2r(Io)] independent reflections remained and all
were used to refine 487 parameters. The structure was
solved by a combination of direct methods and differ-
ence-Fourier syntheses. All non-hydrogen atoms were
refined with anisotropic displacement parameters. All
hydrogen atoms were placed in calculated positions and
refined using a riding model. Full-matrix least-squares
CH2-(OPPh2)2RhCl]2 shows a crystallographic Ci symme-
try with an operator to equivalent atoms of (1 ꢀ x, 1 ꢀ y,
ꢀz) [7].
10. Complexation with mono-phosphinites
10.1. General procedure
P
2
refinements were carried out by minimizing
w(Fo
ꢀ
2 2
Fc ) and converged with R1 = 0.0303 [Io > 2r(Io)],
wR2 = 0.0780 [all data], GOF = 1.189, and shift/error
<0.001. The final difference-Fourier map shows no striking
One hundred and fifty milligrams (0.304 mmol, 1 equiv.)
of [(COD)RhCl]2 and 179.6 mg (0.621 mmol; 2.04 equiv.)
of 2-Br-phenyl-O-(diisopropylphosphinite) are dissolved
in 5 mL of dichloromethane and it was stirred for 30 min
Then the solvent was removed in vacuo to receive a yellow
solid which was washed with 3 mL of pentane and dried in
vacuo (yield: 303 mg; 0.57 mmol; 92%).
features (Demin/max = +0.63/ꢀ0.46 e Aꢀ3). The target
˚
molecule [Biphen(OPCy2)2RhCl]2 shows a crystallographic
C2 symmetry with an operator to equivalent atoms of
(1/2 ꢀ x, y, ꢀz) [7].
9.2.1.4.
[Cy-1,2-CH2-(OPPh2)2RhCl]2. 1H
NMR
10.1.1. (COD)Rh(Cl)(2-Br-phenyl-O-(diisopropyl-
phosphinite))
(CDCl3, ppm): 1.14–1.69 (10H, m), 3.46 (4H, br t), 4.12
2
3
3
(4H, dd JHH = 10.2 Hz JPH = 25.9 Hz), 7.00–7.08 (4H,
m), 7.14 (6H, m), 7.22 (6H, m), 7.76 (4H, m); 13C NMR
(CDCl3, ppm): 14.18 (s), 22.70 (s), 26.88 (s), 31.24 (d
JCP = 4.5 Hz), 43.57 (d JCP = 13.5 Hz), 73.15 (d
JCP = 13.6 Hz), 127.43 (m), 128.92 (d JCP = 18.9 Hz),
129.92 (d JCP = 10.9 Hz), 131.16 (m), 131.72 (m), 133.42
1H NMR (CDCl3, ppm): 1.35 (3H, d JHH = 7.2 Hz),
3
3
1.38 (3H, d JHH = 7.2 Hz), 1.52 (3H, d JHH = 7.2 Hz),
3
1.57 (3H, d JHH = 7.2 Hz), 1.98 (4H, m), 2.25 (4H, m),
3
2.75 (2H, hept JHH = 7.2 Hz), 3.75 (2H, br s), 5.48 (2H,
br s); 6.96 (1H, t JHH = 7.2 Hz), 7.31 (1H, t JHH
7.2 Hz), 7.54 (1H,
3JHH = 7.2 Hz), 7.68 (1H,
3
3
=
d
d
(m), 133.70 (m); 31P NMR (CDCl3, ppm): 134.8 (1 JRhP
=
3JHH = 7.2 Hz); 13C NMR (CDCl3, ppm): 17.89 (s), 19.33
(d JCP = 3.9 Hz), 28.08 (s), 30.45 (d JCP = 18.5 Hz), 32.98
(d JCP = 2.9 Hz), 70.05 (d JCRh = 13.6 Hz), 108.07 (dd
JCRh = 5.8 Hz JCP = 12.4 Hz), 114.42 (d JCP = 3.9 Hz),
120.32 (d JCP = 4.9 Hz), 124.15 (s), 128.09 (s), 133.63 (s),
151.82 (d JCP = 8.8 Hz); 31P NMR (CDCl3, ppm): 164.5
(1JRhP = 174.4 Hz); EA Calc. for C20H30RhOPBrCl: C,
44.84; H, 5.64; P, 5.78. Found: C, 44.99; H, 5.61; P, 5.87%.
225.8 Hz), 134.9 (1JRhP = 225.9 Hz); EA Calc. for
C32H34RhO2P2Cl: C, 59.05; H, 5.26; P, 9.52. Found: C,
58.94; H, 5.14; P, 9.89%.
9.2.1.5. Crystal-structure analysis of [Cy-1,2-CH2-
(OPPh2)2RhCl]2. C64H68Cl2O4P4Rh2 Æ 2(CH2Cl2), Mr =
1471.64, yellow fragment (0.20 · 0.25 · 0.64 mm3), mono-
clinic, P21/c (No.: 14), a = 8.7952(1), b = 23.0017(2), c =
3
˚
˚
16.1431(1) A, b = 93.3354(3)ꢀ, V = 3260.29(5) A , Z = 2,
dcalc = 1.499 g cmꢀ3, F000 = 1504, l = 0.897 mmꢀ1. Preli-
minary examination and data collection were carried out
on a j-CCD device (NONIUS, MACH3) with an Oxford
Cryosystems cooling system at the window of a rotating
anode (NONIUS FR591) with graphite monochromated
10.1.2. Crystal-structure analysis of (COD)Rh(Cl)(2-Br-
phenyl-O-(diisopropylphosphinite))
C20H30BrClOPRh, Mr = 535.67, yellow fragment
3
ꢀ
(0.08 · 0.12 · 0.19 mm ), triclinic, P1 (No.: 2), a = 7.7636(1),
˚
b = 10.6205(1), c = 14.5641(2) A, a = 103.1144(6)ꢀ, b =
3
˚
104.4772(6)ꢀ, c = 103.8815(6)ꢀ, V = 1074.92(2) A , Z = 2,
Mo Ka radiation (k = 0.71073 A). Data collection were
dcalc = 1.655 g cmꢀ3, F000 = 540, l = 2.858 mmꢀ1. Preli-
minary examination and data collection were carried out
on a j-CCD device (NONIUS, MACH3) at the window
of a rotating anode (NONIUS FR591) with graphite
˚
performed at 123 K within the H range of 2.18ꢀ < H <
25.37ꢀ. A total of 28031 intensities were integrated. Raw
data were corrected for Lorentz, polarization, and, arising
from the scaling procedure, for latent decay and absorption
effects. After merging (Rsig = 0.0176), 5982 [5527:
Io > 2r(Io)] independent reflections remained and all were
used to refine 514 parameters. The structure was solved
by a combination of direct methods and difference-Fourier
syntheses. All non-hydrogen atoms were refined with
anisotropic displacement parameters. All hydrogen atoms
were placed in calculated positions and refined using a rid-
˚
monochromated Mo Ka radiation (k = 0.71073 A). Data
collection were performed at 293 K within the H range of
1.52ꢀ < H < 25.41ꢀ. A total of 28031 intensities were inte-
grated. Raw data were corrected for Lorentz, polarization,
and, arising from the scaling procedure, for latent decay
and absorption effects. After merging (Rsig = 0.0244),
3443 [3077: Io > 2r(Io)] independent reflections remained
and all were used to refine 230 parameters. The structure
was solved by a combination of direct methods and differ-
ence-Fourier syntheses. All non-hydrogen atoms were
refined with anisotropic displacement parameters. All
hydrogen atoms were placed in calculated positions and
refined using a riding model. Full-matrix least-squares
ing model. Full-matrix least-squares refinements were car-
ried out by minimizing
P
2
2 2
w(Fo ꢀ Fc ) and converged
with R1 = 0.0235 [Io > 2r(Io)], wR2 = 0.0601 [all data],
GOF = 1.092, and shift/error <0.001. The final differ-
ence-Fourier map shows no striking features (Demin/
P
2
max = +0.47/ꢀ0.30 e Aꢀ3). The target molecule [Cy-1,2-
refinements were carried out by minimizing
w(Fo
ꢀ
˚

888
2 2
K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
Fc ) and converged with R1 = 0.0408 [Io > 2r(Io)],
wR2 = 0.0942 [all data], GOF = 1.151, and shift/error
<0.001. The final difference-Fourier map shows no striking
JCP = 12.4 Hz), 114.62 (s), 120.39 (d JCP = 5.1 Hz), 124.12
(s), 128.10 (s), 133.71 (s), 152.05 (d JCP = 11.0 Hz); 31P
NMR (CDCl3, ppm): 125.3 (1JRhP = 180.3 Hz); FAB(MS):
601 (m+, C26H26OPClBrRh), correct isotopic pattern.
features (Demin/max = +0.80/ꢀ0.53 e Aꢀ3) [7].
˚
10.1.3. (COD)Rh(Cl)(2-Br-phenyl-O-(dicyclohexyl-
phosphinite))
10.1.6. (COD)Rh(Cl)(2-Br-benzyl-O-(diisopropyl-
phosphinite))
1H NMR (CDCl3, ppm): 1.3–2.55 (30H, several m), 3.82
(2H, br s), 5.48 (2H, br s), 6.95 (1H, t 3JHH = 7.2 Hz), 7.31
1H NMR (CDCl3, ppm): 1.3–2.55 (19H, several m), 3.82
(2H, br s), 5.48 (2H, br s), 6.95 (1H, t 3JHH = 7.2 Hz), 7.31
3
3
3
3
(1H, t JHH = 7.2 Hz), 7.54 (2H, br d JHH = 7.2 Hz); 13C
NMR (CDCl3, ppm): 25.26 (s), 26.08 (d JCP = 11.0 Hz),
26.32 (d JCP = 12.4 Hz), 27.11 (d JCP = 5.9 Hz), 28.22 (s),
32.00 (s), 39.94 (d JCp = 16.8 Hz), 70.08 (d JCRh = 13.2
Hz), 78.68 (d JCRh = 13.9 Hz), 107.61 (dd JCRh = 5.8 Hz
JCP = 12.44 Hz), 120.37 (s), 124.13 (s), 128.11 (s), 133.71
(s), 152.12 (d JCP = 8.8 Hz); 31P NMR (CDCl3, ppm):
162.4 (1JRhP = 174.6 Hz); EA Calc. for C26H38RhOPBrCl:
C, 50.71; H, 6.34; P, 5.03. Found: C, 50.67; H, 6.34; P,
5.4%.
(1H, t JHH = 7.2 Hz), 7.54 (2H, br d JHH = 7.2 Hz); 13C
NMR (CDCl3, ppm): 18.39 (s), 18.47 (d JCP = 5.1 Hz),
27.82 (d JCP = 16.8 Hz), 28.37 (s), 33.19 (s), 67.35 (d
JCRh = 13.2 Hz), 69.82 (d JCRh = 13.9 Hz), 106.95 (d
JCRh = 5.9 Hz), 107.09 (d JCRh = 5.9 Hz), 121.62 (s),
127.70 (d JCP = 9.5 Hz), 129.25 (s), 132.53 (s), 136.85 (d
JCP = 5.1 Hz); 31P NMR (CDCl3, ppm): 158.6
(1JRhP = 176.4 Hz); EA Calc. for C21H32RhOPBrCl: C,
45.88; H, 5.87; P, 5.63; Rh, 18.72. Found: C, 45.86; H,
5.79; P, 5.45; Rh, 18.6%.
10.1.4. Crystal-structure analysis of (COD)Rh(Cl)
(2-Br-phenyl-O-(dicyclohexylphosphinite))
10.1.7. (COD)Rh(Cl)(2,4-difluoro-6-Br-phenyl-O-(diiso-
propylphosphinite))
3
C26H38BrClOPRh, Mr = 615.79, yellow fragment
1H NMR (CDCl3, ppm): 1.26 (6H, dd JHH = 7.4 Hz
(0.10 · 0.12 · 0.14 mm3), monoclinic, P21/n (No.: 14),
3JPH = 16.0 Hz), 1.37 (6H, dd JHH = 7.4 Hz JPH
=
3
3
˚
a = 8.5885(1), b = 18.4416(2), c = 16.9592(2) A, b =
16.0 Hz), 1.92 (2H, br s), 2.18-2.3 (6H, m), 2.73 (2H, dhept
3
2
92.5055(4)ꢀ, V = 2683.53(5) A , Z = 4, dcalc = 1.524 g cmꢀ3
,
3JHH = 7.4 JHP = 15 Hz), 3.91 (2H, br s), 5.29 (2H, br s),
˚
F000 = 1256, l = 2.300 mmꢀ1. Preliminary examination and
data collection were carried out on a j-CCD device (NON-
IUS, MACH3) at the window of a rotating anode (NON-
IUS FR591) with graphite monochromated Mo Ka
6.77 (1H, br t JHF = 7.4 Hz), 7.00 (1H, d JHF = 7.4 Hz);
3
3
31P NMR (CDCl3, ppm): 175.9 (dd, JRhP = 174.3 Hz,
1
4JPF = 14.7 Hz); EA Calc. for C20H28RhOPBrClF2:
C, 42.02; H, 4.94; P, 5.42. Found: C, 42.35; H, 4.84; P,
5.62%.
˚
radiation (k = 0.71073 A). Data collection were performed
at 293 K within the H range of 1.63ꢀ < H < 25.35ꢀ. A total
of 61537 intensities were integrated. Raw data were cor-
rected for Lorentz, polarization, and, arising from the scal-
ing procedure, for latent decay and absorption effects. After
merging (Rsig = 0.0352), 4926 [3974: Io > 2r(Io)] indepen-
dent reflections remained and all were used to refine 280
parameters. The structure was solved by a combination of
direct methods and difference-Fourier syntheses. All non-
hydrogen atoms were refined with anisotropic displacement
parameters. All hydrogen atoms were placed in calculated
positions and refined using a riding model. Full-matrix
10.1.8. Crystal-structure analysis of (COD)Rh(Cl)
(2,4-difluoro-6-Br-phenyl-O-(diisopropylphosphinite))
C20H28BrClF2OPRh, Mr = 571.65, yellow fragment
(0.13 · 0.18 · 0.19 mm3), monoclinic, P21/n (No.: 14),
˚
a = 8.2136(2), b = 26.3662(6), c = 10.7809(3) A, b =
3
˚
106.5661(11)ꢀ, V = 2237.82(10) A , Z = 4, dcalc = 1.697 g
cmꢀ3, F000 = 1144, l = 2.764 mmꢀ1. Preliminary examina-
tion and data collection were carried out on a j-CCD
device (NONIUS, MACH3) at the window of a rotating
anode (NONIUS FR591) with graphite monochromated
˚
least-squares refinements were carried out by minimizing
Mo Ka radiation (k = 0.71073 A). Data collection were
P
2
2 2
w(Fo ꢀ Fc ) and converged with R1 = 0.0426 [Io >
2r(Io)], wR2 = 0.0790 [all data], GOF = 1.093, and shift/
error <0.001. The final difference-Fourier map shows no
performed at 293 K within the H range of 1.54ꢀ <
H < 25.34ꢀ. A total of 14420 intensities were integrated.
Raw data were corrected for Lorentz, polarization, and,
arising from the scaling procedure, for latent decay and
absorption effects. After merging (Rsig = 0.0585), 3964
[2899: Io > 2r(Io)] independent reflections remained and
all were used to refine 248 parameters. The structure was
solved by a combination of direct methods and differ-
ence-Fourier syntheses. All non-hydrogen atoms were
refined with anisotropic displacement parameters. All
hydrogen atoms were placed in calculated positions and
refined using a riding model. Full-matrix least-squares
striking features (Demin/max = +0.53/ꢀ0.56 e Aꢀ3) [7].
˚
10.1.5. (COD)Rh(Cl)(2-Br-phenyl-O-(diphenyl-
phosphinite))
1H NMR (CDCl3, ppm): 2.09 (4H, m), 2.32 (4H, br s),
3.57 (2H, br s), 5.62 (2H, br s), 6.96 (1H, t 3JHH = 7.2 Hz),
7.19 (2H, t 3JHH = 7.2 Hz), 7.43 (6H, br s), 7.52 (2H, d and
d overlapp), 7.92 (4H, m); 13C NMR (CDCl3, ppm): 26.27
(s), 27.10 (d JCP = 11.0 Hz), 27.20 (d JCP = 12.4 Hz), 28.15
(d JCP = 1.5 Hz), 29.25 (s), 33.01 (s), 40.94 (d JCP = 17.6 Hz),
70.91 (d JCRh = 13.9 Hz), 107.57 (dd JCRh = 5.9 Hz
P
2
refinements were carried out by minimizing
w(Fo
ꢀ
2 2
Fc ) and converged with R1 = 0.0564 [Io > 2r(Io)],

K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
889
wR2 = 0.1119 [all data], GOF = 1.055, and shift/error
10.1.12. (COD)Ir(Cl)(2-Br-benzyl-O-(diisopropyl-
phosphinite))
1H NMR (CDCl3, ppm): 1.19 (3H, d JHH = 7.4 Hz),
<0.001. The final difference-Fourier map shows no striking
features (Demin/max = +0.82/ꢀ0.70 e Aꢀ3) [7].
3
˚
3
3
1.23 (3H, d JHH = 7.4 Hz), 1.24 (3H, d JHH = 7.4 Hz),
3
10.1.9. (COD)Ir(Cl)(2,4-difluoro-6-Br-phenyl-O-(diiso-
propylphosphinite))
1.28 (3H, d J HH = 7.4 Hz), 1.54–1.70 (4H, m), 1.99–2.06
3
2
(4H, m), 2.64 (dhept JHH = 7.4 Hz, JPH = 7.45 Hz),
3
3
1H NMR (CDCl3, ppm): 1.33 (6H, dd JHH = 7.3 Hz
3.38 (2H, br s), 4.72 (2H, d JPH = 4.9 Hz), 4.83 (2H, br
s), 7.02 (1H, t JHH = 7.4 Hz), 7.19 (1H, t JHH = 7.4 Hz),
3
3
3
3JPH = 15.9 Hz), 1.42 (6H,
d
3JHH = 7.4 Hz JPH
=
3
3
14.7 Hz), 1.66-1.81 (4H, m), 2.01–2.17 (4H, m), 2.95 (2H,
7.25 (1H, d JHH = 7.4 Hz), 7.36 (1H, d JHH = 7.4 Hz);
13C NMR (CDCl3, ppm): 18.00 (d JCP = 4.4 Hz), 18.30
(s), 27.90 (s), 28.89 (s), 33.53 (d JCP = 3.7 Hz), 52.90 (s),
67.23 (s), 95.54 (d JCP = 5.9 Hz), 121.54 (s), 127.62 (d
JCP = 5.9 Hz), 129.19 (s), 132.43 (s), 136.75 (d
JCP = 5.1 Hz); 31P NMR (CDCl3, ppm): 131.6 (s); EA
Calc. for C21H32IrOPBrCl: C, 39.47; H, 5.05; P, 4.85.
Found: C, 39.86; H, 4.91; P, 5.02%.
3
hept JHH = 7.4 Hz), 3.52 (2H, br s), 5.04 (2H, br s), 6.84
3
4
(1H, dt JHF = 11 Hz JHH = 2.5 Hz), 7.08 (1H, dd
3JHF = 7.3 Hz JHH = 2.4 Hz); 31P NMR (CDCl3, ppm):
4
146.3 (4JFP = 3.9 Hz); 19F NMR (CDCl3, ppm): ꢀ166.8
(s), ꢀ115.3 (s); FAB(MS): 661 (m+, C20H28OPBrF2ClIr),
correct isotopic pattern.
10.1.10. Crystal-structure analysis of (COD)Ir(Cl)(2,4-F-
2-Br-phenyl-O-(diisopropylphosphinite))
10.1.13. Crystal-structure analysis of (COD)Ir(Cl)(2-Br-
benzyl-O-(diisopropylphosphinite))
C20H28BrClF2IrOP, Mr = 660.96, yellow fragment
(0.16 · 0.16 · 0.19 mm3), monoclinic, P21/n (No.: 14),
C21H32BrClIrOP, Mr = 639.01, yellow fragment
a = 8.2059(1), b = 26.3152(3), c = 10.7887(1) A, b =
(0.09 · 0.12 · 0.14 mm3), monoclinic, P21/n (No.: 14),
˚
3
˚
˚
106.2761(5)ꢀ, V = 2236.34(4) A , Z = 4, dcalc = 1.963
a = 7.4756(1), b = 22.9235(4), c = 13.6594(2) A, b =
gcmꢀ3, F000 = 1272, l = 7.972 mmꢀ1. Preliminary exami-
nation and data collection were carried out on a j-CCD
device (NONIUS, MACH3) at the window of a rotating
anode (NONIUS FR591) with graphite monochromated
105.708(1)ꢀ, V = 2253.35(6) A , Z = 4, dcalc = 1.884 g
3
˚
cmꢀ3, F000 = 1240, l = 7.896 mmꢀ1. Preliminary examina-
tion and data collection were carried out on a j-CCD
device (NONIUS, MACH3) with an Oxford Cryosystems
cooling system at the window of a rotating anode (NON-
IUS FR591) with graphite monochromated Mo Ka radia-
˚
Mo Ka radiation (k = 0.71073 A). Data collection were
performed at 293 K within the H range of 1.55ꢀ < H <
25.38ꢀ. A total of 55938 intensities were integrated. Raw
data were corrected for Lorentz, polarization, and, arising
from the scaling procedure, for latent decay and absorption
effects. After merging (Rsig = 0.0527), 4096 [2978:
Io > 2r(Io)] independent reflections remained and all were
used to refine 248 parameters. The structure was solved
by a combination of direct methods and difference-Fourier
syntheses. All non-hydrogen atoms were refined with
anisotropic displacement parameters. All hydrogen atoms
were placed in calculated positions and refined using a rid-
ing model. Full-matrix least-squares refinements were
˚
tion (k = 0.71073 A). Data collection were performed at
173 K within the H range of 1.78ꢀ < H < 25.39ꢀ. A total
of 54195 intensities were integrated. Raw data were cor-
rected for Lorentz, polarization, and, arising from the scal-
ing procedure, for latent decay and absorption effects.
After merging (Rsig = 0.0328), 4124 [3505: Io > 2r(Io)] inde-
pendent reflections remained and all were used to refine 219
parameters. The structure was solved by a combination of
direct methods and difference-Fourier syntheses. All non-
hydrogen atoms were refined with anisotropic displacement
parameters. All hydrogen atoms were placed in calculated
positions and refined using a riding model. Full-matrix
2
2 2
carried out by minimizing Rw(Fo ꢀ Fc ) and converged
with R1 = 0.0431 [Io > 2r(Io)], wR2 = 0.0862 [all data],
GOF = 1.020, and shift/error <0.001. The final differ-
least-squares refinements were carried out by minimizing
P
2
2 2
w(Fo ꢀ Fc )
and converged with R1 = 0.0471
ence-Fourier map shows no striking features (Demin/max
=
[Io > 2r(Io)], wR2 = 0.0892 [all data], GOF = 1.221, and
+1.27/ꢀ0.88 e Aꢀ3) [7].
shift/error <0.001. (Demin/max = +1.56/ꢀ1.01 e Aꢀ3). A dis-
˚
˚
order over two positions [0.649(4):0.351(4)] of the (2-Br-
benzyl)-moiety could be resolved clearly [7].
10.1.11. (COD)Ir(Cl)(2,6-Br-phenyl-O-(diisopropyl-
phosphinite))
3
1H NMR (CDCl3, ppm): 1.33 (6H, dd JHH = 7.2 Hz
10.1.14. (COD)Ir(H)(Cl)(2-Br-phenyl-O-
(diisopropylphosphinite))
3
3
3JHP = 18.0 Hz), 1.43 (6H, dd JHH = 7.2 Hz JHP
=
2
12.0 Hz), 1.52-1.66 (4H, m), 1.91 (4H, m), 3.10 (2H, br
1H NMR (CDCl3, ppm): ꢀ16.44 (1H, d JPH
=
3
2
s), 3.14 (2H, dhept JHH = 7.2 Hz JPH = 13.2 Hz), 5.03
(2H, br s),6.75 (1H, 3JHH = 8.4 Hz), 7.43 (2H,
3JHH = 8.4 Hz); 13C NMR (CDCl3, ppm): 18.22 (s), 18.27
(s), 18.28 (s), 18.31 (s), 28.16 (d, JCP = 1.5 Hz), 31.18 (d,
13.5 Hz), 1.0–1.6 (12H, m), 2.48 (2H, m), 2.62 (2H, m),
3
2.96 (2H, m), 3.52 (2H, hept JHH = 7.4 Hz), 4.78 (1H, br
s), 5.00 (1H, br s), 5.08 (1H, br s); 5.45 (1H, br s), 6.58
3
3
(1H, t JHH = 7.4 Hz), 6.67 (1H, d JHH = 7.4 Hz), 7.05
3
JCP = 26.4 Hz), 33.52 (s), 52.30 (s), 96.82 (d, JCP
=
(1H, d JHH = 7.4 Hz); 13C NMR (CDCl3, ppm): 16.15
13.9 Hz), 117.25 (s), 125.04 (s), 132.40 (s), 150.61 (d,
(d JCP = 5.1 Hz), 16.49 (d JCP = 5.9 Hz), 17.96 (d
JCP = 4.4 Hz), 18.07 (s), 27.27 (s), 27.89 (s), 27.99 (s),
JCP = 8.0 Hz); 31P NMR (CDCl3, ppm): 134.3.

890
K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
28.21 (s), 28.75 (s), 28.75 (s), 29.11 (s), 30.22 (d JCP
2.9 Hz), 31.72 (s), 33.52 (s), 82.08 (s), 90.78 (s), 94.68 (d
JCP = 9.5 Hz), 100.00 (d JCP = 14.6 Hz), 105.2 (d
=
into a new flask via canula from which the solvent is
removed in vacuo. A deeply red solid is obtained (yield:
130 mg; 0.31 mmol; 55%). In some cases only a red viscose
oil was received. This material can be used for the further
reactions, as well.
JCP = 13.9 Hz), 123.29 (s), 128.91 (s), 159.3 (d JCP
=
8.1 Hz); 31P NMR (CDCl3, ppm): 146.9 (1JHP = 13.5 Hz);
EA Calc. for C20H30IrOPBrCl: C, 38.43; H, 4.84; P, 4.96.
Found: C, 38.46; H, 4.73; P, 4.99%.
11.1.1. (COD)Rh(2-phenyl-O-(diisopropylphosphinite))
3
1H NMR (C6D6, ppm): 0.97 (6H, dd JHH = 7.4 Hz
3
3
10.1.15. Crystal-structure analysis of (COD)Ir(H)(Cl)-
(2-Br-phenyl-O-(diisopropylphosphinite))
3JHP = 13.5 Hz), 1.11 (6H, dd JHH = 7.4 Hz JHP
=
13.5 Hz), 1.88 (2H, m 3JHH = 7.4 Hz 3JPH = 13.5 Hz), 2.05
C20H30BrClIrOP, Mr = 624.98, light yellow fragment
(2H, m), 2.17 (4H, m), 4.39 (2H, s), 5.69 (2H, s), 7.02 (1H, t
3
(0.11 · 0.16 · 0.24 mm3), monoclinic, P21/c (No.: 14),
3J HH = 7.4 Hz), 7.12 (1H, t JHH = 7.4 Hz), 7.27 (1H, t
3
a = 15.0935(2), b = 9.2737(1), c = 15.1021(2) A, b =
3JHH = 7.4 Hz), 7.42 (1H, t JHH = 7.4 Hz); 13C NMR
˚
3
˚
90.3042(5)ꢀ, V = 2113.85(5) A , Z = 4, dcalc = 1.964
(C6D6, ppm): 17.30 (s), 17.85 (d JCP = 6.6 Hz), 29.25 (d
JCP = 3.7), 29.32 (s), 29.46 (d JCP = 3.7 Hz), 32.15 (s),
g cmꢀ3, F000 = 1208, l = 8.414 mmꢀ1. Preliminary exami-
nation and data collection were carried out on a j-CCD
device (NONIUS, MACH3) at the window of a rotating
anode (NONIUS FR591) with graphite monochromated
81.19 (d JCRh = 7.3 Hz), 98.63 (dd JCP = 7.3 Hz JCRh
=
10.2 Hz), 110.01 (d JCP = 14.6 Hz), 120.86 (s), 126.76 (s),
136.70 (s), 148.94 (dd JCP = 8.8 Hz JCRh = 35.9 Hz),
168.66 (d JCP = 14.6 Hz); 31P NMR (C6D6, ppm): 188.2
(1JRhP = 196.2 Hz); EA Calc. for C20H30RhOP: C, 57.15;
H, 7.19; P, 7.37. Found: C, 57.32; H, 7.01; P, 7.96%.
˚
Mo Ka radiation (k = 0.71073 A). Data collection were
performed at 293 K within the H range of 1.35ꢀ < H <
25.36ꢀ. A total of 55938 intensities were integrated. Raw
data were corrected for Lorentz, polarization, and, arising
from the scaling procedure, for latent decay and absorption
effects. After merging (Rsig = 0.0284), 3884 [3235: Io >
2r(Io)] independent reflections remained and all were used
to refine 227 parameters. The structure was solved by a
combination of direct methods and difference-Fourier syn-
theses. All non-hydrogen atoms were refined with aniso-
tropic displacement parameters. All hydrogen atoms were
placed in calculated positions and refined using a riding
11.1.2. Crystal-structure analysis of (COD)Rh(2-phenyl-O-
(diisopropylphosphinite))
C20H30OPRh, Mr = 420.32, red fragment (0.11 · 0.12 ·
3
ꢀ
0.18 mm ), triclinic, P1 (No.: 2), a = 8.2636(2), b =
˚
10.2594(2), c = 12.6656(4) A, a = 71.5921(12)ꢀ, b =
3
˚
80.1638(13), c = 66.8633(11), V = 935.55(4) A , Z = 2,
dcalc = 1.492 gcmꢀ3, F000 = 436, l = 1.001 mmꢀ1. Prelimin-
ary examination and data collection were carried out on a
j-CCD device (NONIUS, MACH3) with an Oxford Cryo-
systems cooling system at the window of a rotating anode
(NONIUS FR591) with graphite monochromated Mo Ka
model. Full-matrix least-squares refinements were carried
P
2
2 2
out by minimizing
w(Fo ꢀ Fc ) and converged with
R1 = 0.0286 [Io > 2r(Io)], wR2 = 0.0598 [all data],
GOF = 1.083, and shift/error <0.009. The final differ-
˚
radiation (k = 0.71073 A). Data collection were performed
ence-Fourier map shows no striking features (Demin/max
=
at 173 K within the H range of 1.70ꢀ < H < 24.78ꢀ. A total
of 19745 intensities were integrated. Raw data were cor-
rected for Lorentz, polarization, and, arising from the scal-
ing procedure, for latent decay and absorption effects.
After merging (Rsig = 0.0436), 3143 [2690: Io > 2r(Io)] inde-
pendent reflections remained and all were used to refine 212
parameters. The structure was solved by a combination of
direct methods and difference-Fourier syntheses. All non-
hydrogen atoms were refined with anisotropic displacement
parameters. All hydrogen atoms were placed in calculated
positions and refined using a riding model. Full-matrix
least-squares refinements were carried out by minimizing
+0.77/ꢀ0.73 e Aꢀ3). The hydrogen atom bound to the Ir
atom could be located in the final difference Fourier map.
The refinement with an isotropic displacement parameter
converged with reasonable results [U11 = 0.08(2), Ir–H
˚
˚
1.45(7) A, and Cl–Ir–H 161(2)ꢀ] [7].
11. Ring closure
11.1. General procedure
Three hundred and three milligrams (0.567 mmol;
1 equiv.) of (COD)Rh(Cl)(2-Br-phenyl-O-(diisopropyl-
phosphinite)) is dissolved in 20 mL of diethyl ether. The
solution was cooled with an acetone/dry ice bath. Slowly
0.87 mL (72 mg; 1.124 mmol; 2 equiv.) of a 1.3 molar solu-
tion of sec. BuLi in cyclohexane/hexane are added. It is
allowed to warm to room temperature over night. The
color changes from orange to deeply red. Then 1 mL of
degased water is added at room temperature and it is stir-
red for 1 min. The ether phase is immediately separated via
canula in a new flask containing MgSO4. It is stirred in the
new flask for 5 min and the red ether solution is transferred
2
2 2
Rw(Fo ꢀ Fc )
and converged with R1 = 0.0372
[Io > 2r(Io)], wR2 = 0.0877 [all data], GOF = 1.020, and
shift/error <0.001. The final difference-Fourier map shows
no striking features (Demin/max = +0.71/ꢀ0.53 e Aꢀ3) [7].
˚
11.1.3. (COD)Rh(2-phenyl-O-(dicyclohexylphosphinite))
1H NMR (C6D6, ppm): 1.0–2.3 (30H, several m), 4.50
3
(2H, br s), 5.71 (2H, br s), 7.03 (1H, t JHH = 7.2 Hz),
3
7.24 (1H, t 3JHH = 7.2 Hz), 7.32 (1H, br d JHH = 7.2 Hz),
3
7.48 (1H, d JHH = 7.2 Hz); 13C NMR (C6D6, ppm): 26.44
(s), 26.75 (d
J CP = 10.2 Hz), 27.01 (s), 27.16 (d

K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
891
JCP = 3.7 Hz), 27.75 (s), 28.12 (d JCP = 5.9 Hz), 29.39 (s),
32.18 (s), 38.89 (d J CP = 2.9 Hz), 39.11 (d JCP = 2.9 Hz),
98.29 (dd JCP = 7.3 Hz JCRh = 10.3 Hz), 110.99 (d
JCRh = 14.6 Hz), 120.82 (s), 126.75 (s), 136.69 (s), 149.15
(dd JCP = 8.8 Hz JCRh = 35.9 Hz); 31P NMR (C6D6,
ppm): 182.22 (1JRhP = 196.2 Hz); EA Calc. for
C26H38RhOP: C, 62.40; H, 7.65; P, 6.19. Found: C,
62.55; H, 7.34; P, 6.51%.
gen atoms were refined with anisotropic displacement
parameters. All hydrogen atoms were placed in calculated
positions and refined using a riding model. Full-matrix
least-squares refinements were carried out by minimizing
P
2
2 2
w(Fo ꢀ Fc ) and converged with R1 = 0.0538 [Io >
2r(Io)], wR2 = 0.0981 [all data], GOF = 1.090, and shift/
error <0.001. The final difference-Fourier map shows no
striking features (Demin/max = +0.37/ꢀ0.45 e Aꢀ3). In the
˚
asymmetric unit we found two crystallographic indepen-
dent molecules A and B. They differ only slightly in
their geometric parameters. Data given in Table 2 refer
to A [7].
11.1.4. (COD)Rh(2-phenyl-O-(diphenylphosphinite))
1H NMR (C6D6, ppm): 2.15 (4H, m), 2.22 (4H, br s),
4.48 (2H, br s), 5.98 (2H, br s), 7.15 (6H, m), 7.19 (2H, t
and t overlapp 3JHH = 7.2 Hz), 7.43 (1H, d 3JHH = 7.4 Hz),
3
7.62 (2H, d JHH = 7.4 Hz), 7.84 (4H, m); 13C NMR
11.1.7. (COD)Rh(2,4-difluoro-6-phenyl-O-(diisopropyl-
phosphinite))
(C6D6, ppm): 29.53 (s), 31.44 (s), 84.49 (d JCRh = 6.6 Hz),
101.22 (dd JCP = 7.4 Hz JCRh = 18.3), 112.05 (d
JCP = 16.1 Hz), 121.53 (s), 127.05 (s), 128.60 (d
JCP = 9.5 Hz), 130.68 (s), 131.05 (d JCP = 14.6 Hz),
136.86 (s), 149.72 (dd JCP = 9.5 Hz JCRh = 35.1 Hz),
166.92 (d JCP = 18.3 Hz); 31P NMR (C6D6, ppm): 153.7
(1JRhP = 206.1 Hz).
1H NMR (C6D6, ppm): 0.92 (6H, dd 3JHH = 7.4 Hz
3
3
3JPH = 14.6 Hz), 1.12 (6H, dd JHH = 7.4 Hz JPH
=
14.6 Hz), 1.7–2.3 (8H, m), 4.39 (2H, br s), 5.42 (2H, br s),
3
3
6.72 (1H, t JHH = 7.2 Hz), 6.95 (1H, d JHH = 7.2 Hz);
13C NMR (C6D6, ppm): 17.10 (s), 17.68 (d JCP = 7.3 Hz),
29.13 (s), 29.53 (d JCP = 18.3 Hz), 31.93 (s), 82.49 (d
JCRh = 7.3 Hz), 99.62 (dd JCP = 7.3 Hz JCRh = 10.3 Hz),
101.24 (dd JCP = 22.0 Hz JCF = 5.9 Hz), 116.54 (dd
11.1.5. (COD)Rh(2-benzyl-O-(diisopropylphosphinite))
3
1H NMR (C6D6, ppm): 0.72 (6H, dd JHH = 7.4 Hz
JCP = 16.1 Hz JCF = 3.7), 153.52 (dd JCP = 10.2 Hz JCRh =
3JHP = 15.6 Hz),
0.96
(6H,
dd
3JHH = 7.4 Hz
38.1 Hz), 158.27 (d JCP = 6.6 Hz); 19F NMR (C6D6, ppm):
3
3JHP = 15.6 Hz), 1.63 (2H, dhept JHH = 7.4 Hz), 1.9–2.2
ꢀ129.0, ꢀ122.8; 31P NMR (C6D6, ppm): 194.6 (1JRhP
=
3
(8H, m), 4.24 (2H, br s), 4.83 (2H, d JPH = 32.0 Hz),
192.2 Hz); EA Calc. for C20H28RhOPF2: C, 52.64; H, 6.18.
Found: C, 52.98; H, 6.05%.
3
5.06 (2H, br s), 6.91 (1H, d JHH = 7.4 Hz), 7.16 (1H, t
3JHH = 7.4 Hz), 7.72 (1H, d JHH = 7.4 Hz); 13C NMR
3
(C6D6, ppm): 17.31 (s), 17.82 (d JCP = 6.8 Hz), 28.64 (d
JCP = 23.3 Hz), 30.74 (s), 31.77 (s), 79.88 (dd JCP = 5.8 Hz
JCRh = 11.7), 84.39 (d JCRh = 6.8 Hz), 98.80 (dd
JCP = 7.8 Hz JCRh = 11.7 Hz), 122.81 (s), 126.02 (s),
126.89 (s), 137.42 (s), 143.45 (d JCP = 9.7 Hz), 167.75 (d
JCP = 10.7 Hz JCRh = 32.1 Hz); 31P NMR (C6D6, ppm):
11.1.8. (COD)Ir(2,4-difluoro-6-phenyl-O-(diisopropyl-
phosphinite))
3
1H NMR (C6D6, ppm): 0.84 (6H, dd JHH = 7.4 Hz
3
3JPH = 15.9 Hz), 0.99 (6H,
d
3JHH = 7.4 Hz JPH
=
15.9 Hz), 1.39 (2H, m), 1.71–1.86 (4H, m), 2.00 (4H, m),
3
3.88 (2H, br s), 5.04 (2H, br s), 6.66 (1H, dt JHF = 11
4
3
4
148.2
(1JRhP = 178.2 Hz);
FAB(MS):
434
(m+,
Hz JHH = 2.5 Hz), 7.08 (1H, dd JHF = 7.3 Hz JHH =
C21H32OPRh), correct isotopic pattern.
2.4 Hz); 31P NMR (C6D6, ppm): 175.6; 19F NMR (C6D6,
ppm): ꢀ122.6 (s), ꢀ128.6 (s); FAB(MS): 546 (m+, C20H28-
OPF2Ir), correct isotopic pattern.
11.1.6. Crystal-structure analysis of (COD)Rh(2-benzyl-O-
(diisopropylphosphinite))
C21H32OPRh, Mr = 434.35, red fragment (0.12 · 0.14 ·
11.1.9. (COD)Ir(2-phenyl-O-(diisopropylphosphinite))
3
0.16 mm3), monoclinic, P21/n (No.: 14), a = 17.5016(2),
1H NMR (C6D6, ppm): 0.99 (6H, dd JHH = 7.4 Hz
3
3
b = 14.2038(1), c = 18.0305(2) A, b = 114.0985(4)ꢀ, V =
3JHP = 13.5 Hz), 1.18 (6H, dd JHH = 7.4 Hz JHP = 13.5
˚
3
3
3
4091.54(7) A , Z = 8, dcalc = 1.410 g cmꢀ3, F000 = 1808,
Hz), 1.88 (2H, m JHH = 7.4 Hz JPH = 13.5 Hz), 2.05
˚
l = 0.918 mmꢀ1. Preliminary examination and data collec-
tion were carried out on a j-CCD device (NONIUS,
MACH3) at the window of a rotating anode (NONIUS
FR591) with graphite monochromated Mo Ka radiation
(2H, m), 2.17 (4H, m), 3.98 (2H, s), 5.42 (2H, s), 6.73
3
3
(1H, t JHH = 7.4 Hz), 7.12 (1H, t JHH = 7.4 Hz), 7.42
3
3
(1H, d JHH = 7.4 Hz), 7.48 (1H, d JHH = 7.4 Hz);
13C NMR (C6D6, ppm): 16.98 (s), 17.03 (s), 29.35 (s),
29.67 (s), 29.98 (s), 32.99 (s), 66.72 (s), 88.29 (d
JCP = 12.4 Hz), 104.95 (d JCP = 14.6 Hz), 122.53 (s),
152.40 (d JCP = 6.6 Hz), 166.02 (d, JCP = 13.2 Hz); 31P
NMR (C6D6, ppm): 171.2; EA Calc. for C20H30IrOP: C,
47.13; H, 5.93; P, 6.08. Found: C, 47.48; H, 5.61; P, 6.35%.
˚
(k = 0.71073 A). Data collection were performed at 293 K
within the H range of 1.37ꢀ < H < 25.31ꢀ. A total of
98022 intensities were integrated. Raw data were corrected
for Lorentz, polarization, and, arising from the scaling pro-
cedure, for latent decay and absorption effects. After merg-
ing (Rsig = 0.0606), 7456 [4854: Io > 2r(Io)] independent
reflections remained and all were used to refine 441 param-
eters. The structure was solved by a combination of direct
methods and difference-Fourier syntheses. All non-hydro-
11.1.10. (COD)Ir(2-benzyl-O-(diisopropylphosphinite))
3
1H NMR (C6D6, ppm): 0.74 (6H, dd JHH = 7.4 Hz
3
3
3JHP = 15.6 Hz), 0.99 (6H, dd JHH = 7.4 Hz JHP
=

892
K. Ruhland et al. / Journal of Organometallic Chemistry 693 (2008) 874–893
3
15.6 Hz), 1.75 (2H, dhept JHH = 7.4 Hz), 1.8-2.2 (8H, m),
matrix least-squares refinements were carried out by
P
2
2 2
3.65 (2H, br s), 4.83 (2H, br s), 4.87 (2H,
d
minimizing x(Fo ꢀ Fc ) with the SHELXL-97 weighting
scheme and stopped at shift/err <0.003. The final residual
electron density maps showed no remarkable features
[7].
3JPH = 18.4 Hz), 6.91 (1H, d JHH = 7.4 Hz), 7.16 (1H, t
3
3JHH = 7.4 Hz), 7.24 (1H, t JHH = 7.4 Hz), 7.74 (1H, d
3
3JHH = 7.4 Hz); 13C NMR (C6D6, ppm): 17.21 (s), 17.54
(d JCP = 6.8 Hz), 28.43 (d JCP = 23.3 Hz), 31.56 (s), 32.74
(s), 68.27 (s), 79.71 (s), 88.84 (d JCP = 13.2 Hz), 123.34
(s), 136.46 (s), 143.54 (d JCP = 7.3 Hz), 165.46 (d
JCP = 11.0 Hz); 31P NMR (C6D6, ppm): 128.9; EA Calc.
for C21H32IrOP: C, 48.16; H, 6.16; P, 5.91. Found: C,
48.61; H, 6.00; P, 6.12%.
12. Calculations
The DFT calculations were performed using the program
suite GAUSSIAN 03 [6]. All molecular geometries were fully
optimized. Transition states were obtained using the OPT2
function implemented in the program suite and proven to
be one-dimensional saddle points by frequency analysis.
The DFT method used includes Becke’s three parameter
hybrid exchange functional in combination with the correla-
tion functional of Perdew and Wang (B3PW91). Geometry
calculations and frequency calculations were performed
using the valence double-zeta LANL2DZ basis set.
11.1.11. Crystal-structure analysis of RhClBr(2-phenyl-O-
(diphenylphosphinite))(Br-2-phenyl-O-(diphenyl-
phosphinite))2
C54H42Br4ClO3P3Rh, Mr = 1289.79, yellow fragment
(0.12 · 0.10 · 0.19 mm3), triclinic, P1 (No.: 2), a =
ꢀ
˚
10.8877(5), b = 13.5255(7), c = 18.6668(1) A, a = 69.494(5),
3
˚
b = 101.912(1)ꢀ, v = 72.434(4), V = 2453.9(2) A , Z = 2,
dcalc = 1.746 g cmꢀ3, F000 = 1274, l = 3.802 mmꢀ1. Suit-
able single-crystals for the X-ray diffraction study were
selected under perfluorinated ether and fixed on a glass
capillary. Preliminary examination and data collection
were carried out on an area detecting system and graphite
Supplementary material
CCDC 656929, 656930, 656931, 656932, 656933, 656934,
656935, 656937 and 656938 contains the supplementary
crystallographic data for [Biphen(OPCy2)2RhCl]2, (COD)-
Rh(2-benzyl-O-(diisopropylphosphinite)), (COD)Rh(Cl)-
(2-Br-phenyl-O-(diisopropylphosphinite)), (COD)Rh(Cl)-
(2-Br-phenyl-O-(dicyclohexylphosphinite)), (COD)Ir(H)-
(Cl)(2-Br-phenyl-O-(diisopropylphosphinite)), (COD) Ir(Cl)-
(2,4-F-2-Br-phenyl-O-(diisopropylphosphinite)), (COD)Rh-
(2-phenyl-O-(diisopropylphosphinite)), (COD)Rh(Cl)(2,4-
difluoro-6-Br-phenyl-O-(diisopropylphosphinite)) and [Cy-
1,2-CH2-(OPPh2)2RhCl]2. These data can be obtained free
of charge from The Cambridge Crystallographic Data Cen-
tre via www.ccdc.cam.ac.uk/data_request/cif, or from the
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or
e-mail: deposit@ccdc.cam.ac.uk.
˚
monochromated Mo Ka radiation (k = 0.71073 A). The
unit cell parameters were obtained by full-matrix
least-squares refinements during the scaling procedure.
Data collections were performed at low temperatures
(Oxford Diffraction cooling device) on a Oxford Diffrac-
tion Xcalibur3 system, j-CCD; sealed tube, Enhance
X-ray Source, Spellman DF3; nine data sets in rotation
scan modus with D//Dx = 2.0ꢀ; dx = 50; T = 150 K.
Intensities were integrated and the raw data were corrected
for Lorentz, polarization, and, arising from the scaling pro-
cedure for latent decay and absorption effects. The struc-
tures were solved by a combination of direct methods
and difference Fourier syntheses. All non-hydrogen atoms
were refined with anisotropic displacement parameters.
The difference Fourier map indicates an under occupancy
of all bromine positions and residual electron density peaks
Acknowledgements
˚
with shorter distances of about 0.2 A to the bonding
This work was supported by the DFG (Ru519/3-2). K.
R. thanks Prof. W.A. Herrmann for the ability to use the
infrastructure of his chair. K.R. gratefully acknowledges
the support of Stephan D. Hoffmann who did the X-ray
analysis of RhClBr(2-phenyl-O-(diphenylphosphinite))-
(Br-2-phenyl-O- (diphenylphosphinite))2 and [Biphen-
(OPCy2)2RhCl]2.
carbon atoms or the rhodium atom. The indicated mixed
occupancy with chlorine was refined with free variables
for all positions and refined to a ratio of 0.75:0.25
(Br1/Cl1 and Br2/Cl2), 0.63:0.37 (Br4/Cl4) and 0.38: 0.62
(Br5/Cl5), respectively. The structure solution shows an
heavy atom bonded to the phenyl group coordinated to
˚
the rhodium atom. The bond distance of 1.77 A also indi-
cates a chlorine atom. The difference Fourier map shows an
under occupancy for this position and a small residual elec-
tron density located about 1.0 A to the bonding carbon
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