Ligand behaviour of P-functionally substituted organotin halides: Synthesis, structure, and intramolecular oxidative addition of [{Me2(Cl)SnCH2CH2PPh2} 2Rh(CO)Cl]

Article abstract of DOI:10.1016/S0022-328X(98)00912-7

The reaction of [Rh(CO)₂Cl]₂ with Me₂(Cl)SnCH₂CH₂PPh₂ yields the square-planar rhodium(I) complex [{Me₂(Cl)SnCH₂CH₂PPh₂} ₂Rh(CO)Cl] (1). The crystal structure of 1 is characterized by an intramolecular Rh-ClSn and an intermolecular Sn-ClSn interaction. The latter gives rise to the dimerization of 1 under formation of a 16-membered macrocycle. In solution the complex is monomeric and undergoes a fast exchange between the intramolecular Rh-ClSn contacts of the two ligands. By heating in toluene at 100°C, 1 transforms under elimination of methane and ethylene into the rhodium(III) complex [{Me(Cl)SnCH₂CH₂PPh₂}₂Rh(CO)Cl] (2). Both in solid state and in solution 2 shows a bicyclic structure with two Sn, P, and Rh containing five-membered chelate rings with a σ-Rh-Sn bond.

Full text of DOI:10.1016/S0022-328X(98)00912-7

Journal of Organometallic Chemistry 572 (1999) 117–123
Ligand behaviour of P-functionally substituted organotin halides:
synthesis, structure, and intramolecular oxidative addition of
[{Me2(Cl)SnCH2CH2PPh2}2Rh(CO)Cl]
Dirk Kruber, Kurt Merzweiler, Christoph Wagner, Horst Weichmann *
Institut fu¨r Anorganische Chemie, Martin-Luther-Uni6ersita¨t Halle-Wittenberg, Kurt-Mothes-Straße 2, D-06120 Halle (Saale), Germany
Received 22 July 1998
Abstract
The reaction of [Rh(CO)2Cl]2 with Me2(Cl)SnCH2CH2PPh2 yields the square-planar rhodium(I) complex
[{Me2(Cl)SnCH2CH2PPh2}2Rh(CO)Cl] (1). The crystal structure of 1 is characterized by an intramolecular Rh–Cl···Sn and an
intermolecular Sn–Cl···Sn interaction. The latter gives rise to the dimerization of 1 under formation of a 16-membered
macrocycle. In solution the complex is monomeric and undergoes a fast exchange between the intramolecular Rh–Cl···Sn contacts
of the two ligands. By heating in toluene at 100°C, 1 transforms under elimination of methane and ethylene into the rhodium(III)
¸¹¹¹¹¹¹¹¹¹º
SnCH2CH2PPh2}2Rh
complex [{Me(Cl)
(CO)Cl] (2). Both in solid state and in solution 2 shows a bicyclic structure with two Sn,
P, and Rh containing five-membered chelate rings with a |-Rh–Sn bond. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Rhodium stannyl complexes; Oxidative addition of Sn–C bonds; Pentacoordination; Crystal structures
1. Introduction
Recently, we started investigations of the ligand be-
haviour of P-functionally substituted organotin halides
Me3−m(X)mSn(CH2)nPPh2 (X=Cl, m=1–3; n=2, 3)
and related compounds in transition metal complexes
[10]. In contrast to the compounds mentioned above in
these ligand systems the tin atom is a centre of variable
Lewis-acidity. This should have the following conse-
quences: (i) in reactions of the ligands with transition
metal complexes containing metal–halogen functions
the formation of metal–halogen–tin bridges is expected.
This should influence the structure and the reactivity of
the resulting complexes; (ii) the formation of metallacy-
cles by elimination of the organotin group of the ligands
under formation of |-M–C bonds (e.g. M=Pd or Pt)
can occur in case of a suitable length of the (CH2)n–
bridge in the ligands; (iii) finally, in reactions of Me3−
m(X)mSn(CH2)nPPh2 (m=2, 3) with electron-rich low-
valent metal complexes the formation of compounds
with M“Sn-donor–acceptor interactions is possible
which represent intermediates in oxidative additions of
Sn–Hal bonds of the ligands to the metal centre [11].
ꢀ-Diphenylphosphinoalkyl
triorganostannanes
R3Sn(CH2)nPPh2 (R=Me, Ph; n=2, 3) [1–3] and the
distannanes [Ph2P(CH2)nMe2Sn–]2 (n=2, 3) [3] are
suitable ligands to form phosphinoalkylstannyl chelate
complexes
with
the
structural
element
¸¹¹¹¹¹¹¹¹¹º
[M]’PPh2(CH2)nSnR2 in ‘chelate assisted’ oxidative
additions of their Sn–C(R)– and Sn–Sn-bonds to Pd0,
Pt0 and Fe0 complex fragments [4–8]. The reaction of
Me3SnCH2CH2PMe2 with [Rh(CO)2Cl]2 and Cr(CO)6
yields
Rh(CO)Cl] and [(Me3SnCH2CH2PMe2)Cr(CO)5]. In
these compounds Me3SnCH2CH2PMe2 acts as
the
complexes
[{Me3SnCH2CH2PMe2}2-
a
monodentate ligand by P“M coordination without
any interaction between the tin and transition metal
[2,9].
* Corresponding author. Fax: +49 345 5527028; e-mail: weich-
mann@chemie.uni-halle.de
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00912-7

118
D. Kruber et al. / Journal of Organometallic Chemistry 572 (1999) 117–123
Cl, Rh–P and Rh–C bond lengths are comparable with
In this paper we report the synthesis, molecular
structure, and reactivity of the complex
those in other complexes of the type trans-[RhCl(CO)
(PPh2Alk)2], e.g. trans-[RhCl(CO)(PPh2Me)2] [12].
The geometry around the two tin atoms is a distorted
trigonal bipyramid. In both cases the equatorial plane
is occupied by three carbon atoms, belonging to the
methyl groups and the P-bonded ethylene group, and
one of the axial positions is occupied by the chlorine
atoms Cl(2) and Cl(3), respectively. The pentacoordina-
tion is achieved in different ways: the second axial
position at Sn(2) is occupied by the chlorine atom Cl(1)
of the Rh–Cl function, whereas the coordination
sphere around Sn(1) is completed by the chlorine atom
Cl(2%) of the intermolecularly coordinated Me2(Cl)Sn-
CH2CH2PPh2 ligand of a neighbouring molecule.
Comparing Sn(2) and Sn(1) the trigonal–bipyramidal
skeleton of Sn(1) is distorted more towards a mono-
capped tetrahedron because of the stronger intramolec-
ular Sn(2)···Cl(1) coordination than the intermolecular
Sn(1)···Cl(2%) interaction. This is indicated by the
smaller difference between the sums of the three equa-
torial and the three axial angles to the covalent bonded
Clax at Sn(1) (DS(q)=52.9°) compared with Sn(2)
(DS(u)=75.4°) [13,14], the greater deviation of Sn(1)
[{Ph2PCH2CH2Sn(Cl)Me2}2Rh(CO)Cl].
2. Results and discussion
2.1. Synthesis
The reaction of Me2(Cl)SnCH2CH2PPh2 [3] with
[Rh(CO)2Cl]2 in a molar ratio of 2:1 in benzene at room
temperature yields the complex [{Me2(Cl)SnCH2CH2-
PPh2}2Rh(CO)Cl] (1) (Eq. (1)). To avoid the formation
of dinuclear species solutions of the starting compo-
nents in benzene are dropped simultaneously in pure
benzene.
4Me2(Cl)SnCH2CH2PPh2+[Rh(CO)2Cl]2
C H
6
“6 2[{Me2(Cl)SnCH2CH2PPh2}2Rh(CO)Cl]
(1)
−2CO
1
During the reaction the equivalent amount of CO is
evolved. Pure 1 could be obtained by recrystallization
from CH2Cl2/hexane. The yellow crystals melt at 124–
126°C and are soluble in aromatic and chlorinated
hydrocarbons. A strong absorption at 1975 cm−1 in the
CO valence region of the IR spectrum of 1 (in CsBr)
indicates a square-planar ligand arrangement at the
rhodium(I) centre [2,18].
2.2. Molecular structure of
[{Me2(Cl)SnCH2CH2PPh2}2Rh(CO)Cl] (1)
The molecular structure of 1 along with the atom-
numbering scheme are shown in Fig. 1. Selected bond
lengths and angles are listed in Table 1. The molecular
structure
of
1
shows
that
the
two
Me2(Cl)SnCH2CH2PPh2 ligands are both coordinated
via the phosphorus atom to the rhodium atom. As a
result of its Lewis acidity the tin atom of one ligand
(Sn2) interacts with the chlorine atom at the rhodium
centre to form a six-membered ring with an intramolec-
ular Rh–Cl···Sn bridge. Simultaneously the same atom
(Sn2) is linked with the Me2(Cl)Sn-group of a neigh-
bouring complex molecule via an intermolecular Sn(2)–
Cl(2)···Sn(1%) interaction with the consequence of
formation of centrosymmetric dimers. The crystallo-
graphically imposed inversion centre of the structure
coincides with the midpoint of the sixteen membered
macrocycle formed by the dimerization of 1. No un-
usual contacts between adjacent dimeric species are
observed.
The rhodium atom exhibits a square-planar coordi-
nation sphere with only slight distortion (P(1)–Rh–
P(2) 179.0(1)°, Cl(1)–Rh–C(33) 176.3(2)°). The two
phosphorus atoms are in the trans position. The Rh–
Fig. 1. Molecular structure of [{Me2(Cl)SnCH2CH2PPh2}2Rh(CO)Cl]
(1) with atom-numbering. Hydrogen atoms are omitted for clarity.

D. Kruber et al. / Journal of Organometallic Chemistry 572 (1999) 117–123
119
Table 1
The torsion angles in Table 1 indicate that the
six-membered chelate rings in 1 adopt a boat con-
formation. The Rh, P(1), Sn(2) and C(2) atoms are
nearly co-planar, and the ring is puckered at the
C(1) and Cl(1) edge.
˚
Selected bond lengths (A), angles (°) and endocyclic torsion angles (°)
for [{Me2(Cl)SnCH2CH2PPh2}2Rh(CO)Cl] (1)
˚
Bond lengths (A)
Rh–P(1)
Rh–P(2)
Rh–Cl(1)
Rh–C(33)
Sn(1)–C(4)
Sn(1)–C(7)
Sn(1)–C(8)
Sn(1)–Cl(3)
Sn(1)–Cl(2’)
Sn(2)–C(2)
2.312(1)
2.336(1)
2.363(2)
1.793(5)
2.149(4)
2.118(6)
2.118(6)
2.405(2)
3.254(2)
2.143(5)
Sn(2)–C(5)
Sn(2)–C(6)
Sn(2)–Cl(2)
Sn(2)–Cl(1)
P(1)–C(1)
P(1)–C(9)
P(1)–C(15)
P(2)–C(3)
P(2)–C(21)
P(2)–C(27)
2.118(6)
2.115(6)
2.467(2)
2.920(1)
1.834(5)
1.812(5)
1.815(4)
1.843(4)
1.817(4)
1.815(4)
2.3. Structure of 1 in solution
The results of 1H-, 31P- and 119Sn-NMR spectro-
scopic studies of 1 in C6D6 are summarized in Table 2.
In solution 1 is monomeric. This is proved by osmome-
try in C6H6 at 45°C (MW measured: 966.5 (Calc.
961.4)) and spectroscopic data. The NMR spectra re-
1
veal only one 31P and 119Sn signal and in the H-NMR
Bond angles (°)
P(1)–Rh–P(2)
Cl(1)–Rh–C(33)
P(1)–Rh–Cl(1)
P(1)–Rh–C(33)
P(2)–Rh–Cl(1)
P(2)–Rh–C(33)
C(4)–Sn(1)–C(7)
C(4)–Sn(1)–C(8)
C(7)–Sn(1)–C(8)
Cl(3)–Sn(1)–C(4)
Cl(3)–Sn(1)–C(7)
Cl(3)–Sn(1)–C(8)
Cl(3)–Sn(1)–Cl(2’)
C(2)–Sn(2)–C(5)
C(2)–Sn(2)–C(6)
C(5)–Sn(2)–C(6)
179.0(1)
176.3(2)
88.8(1)
Cl(2)–Sn(2)–C(2)
Cl(2)–Sn(2)–C(5)
Cl(2)–Sn(2)–C(6)
Cl(2)–Sn(2)–Cl(1)
Rh–P(1)–C(1)
90.7(2)
96.7(2)
95.5(2)
spectrum only one signal is shown for the methyl group
protons at the tin atoms. That means, in solution
neither an intermolecular Sn(1)···Cl(2%) nor an in-
tramolecular Sn(2)···Cl(1) interaction exists. On the
other hand, the high-field shift of the 119Sn-NMR signal
88.8(2)
92.1(1)
90.4(2)
176.4(1)
118.2(2)
115.1(2)
111.1(1)
101.8(2)
102.9(2)
106.2(2)
114.0(2)
115.0(2)
113.9(1)
105.5(2)
105.5(2)
101.6(2)
Rh–P(1)–C(9)
2
(112.6 ppm) and the increase of the J(1HC119Sn) cou-
114.4(2)
120.3(3)
117.1(3)
96.9(2)
101.5(2)
100.5(3)
175.0(1)
119.8(3)
118.6(3)
119.9(4)
Rh–P(1)–C(15)
C(1)–P(1)–C(9)
C(1)–P(1)–C(15)
C(9)–P(1)–C(15)
Rh–P(2)–C(3)
Rh–P(2)–C(21)
Rh–P(2)–C(27)
C(3)–P(2)–C(21)
C(3)–P(2)–C(27)
C(21)–P(2)–C(27)
pling constant (60.2 Hz) compared with the ligand
Me2(Cl)SnCH2CH2PPh2 (l119Sn=142 ppm, 2J(1HC119
Sn=57.8 Hz [3]) indicate for the tin atoms in 1 at least
weak hypervalent contacts. Obviously, 1 undergoes a
dynamic process in solution by a fast intramolecular
exchange between Rh–Cl(1)···Sn(1) and Rh–
Cl(1)···Sn(2) interactions. From the unchanged 1H-
NMR spectrum follows that even at −70°C this
process is fast within the NMR time scale.
Torsion angles (°)
Rh–Cl(1)–Sn(2)–C(2)
Cl(1)–Sn(2)–C(2)–C(1)
67.5(2)
3.3(4)
C(2)–C(1)–P(1)–Rh
C(1)–P(1)–Rh–Cl(1)
P(1)–Rh–Cl(1)–Sn(2) −65.7(1)
68.5(5)
15.5(2)
As a consequence of the natural abundance of the
119Sn isotope of 8.58% the dominant isotopomer of 1 in
solution contains only one 119Sn atom (the portion of
the isotopomer with two 119Sn atoms is 0.74%). That
means the 119Sn-NMR spectrum and the satellite part
of the 31P-NMR spectrum of 1 are parts of an AA%X
spin system (A,A%=31P, X=119Sn) because the two
phosphorus atoms are chemically but not magnetically
equivalent. Computer simulation gave the coupling
Sn(2)–C(2)–C(1)–P(1) −74.3(5)
from the plane defined by the three equatorial car-
˚
A;
bon
atoms
(DSn(1)
(plane):
0.356(4)
˚
DSn(2)(plane): 0.160(4) A) [14], and the shorter
Sn(2)···Cl(1) distance compared with Sn(1)···Cl(2%).
The last mentioned Sn···Cl distances are consider-
ably shorter than the sum of corresponding van
2
3
constants J(31P, 31P)=338.9 and J(31P, 119Sn)=203.2
˚
der Waals radii (3.85 A [15]) and indicate substan-
Hz.
tial bonding. Finally, the small difference of 0.062
˚
A
between the bond lengths Sn(1)–Cl(3) and
2.4. Intramolecular oxidati6e addition reaction of 1
Sn(2)–Cl(2) reflects the shortening of axial Sn–Cl
bonds in a trigonal–bipyramidal ligand polyhedron,
with increasing deviation from the ideal geometry
towards a monocapped tetrahedron.
Heating 1 in toluene for 2 days at 100°C the
formerly yellow solution turns to orange and after
evaporation to dryness the yellow rhodium(III)
¸¹¹¹¹¹¹¹¹¹º
Both the Sn–C bond lengths and the bond
lengths and angles at the phosphorus atoms show
complex [{Me(Cl)SnCH2CH2PPh2}2Rh(CO)Cl] (2)
could be isolated (Eq. (2)). Recrystallization from
CH2Cl2/hexane yields a pure product.
[{Me2(Cl)SnCH2CH2PPh2}2Rh(CO)Cl]tꢀolꢀueꢀnꢀeꢀ/1ꢀ00ꢀ°ꢀCꢀ/2ꢁd[{Me(Cl)SnCH2CH2PPh2}2Rh(CO)Cl]
(2)
¸¹¹¹¹¹¹¹¹¹º
−CH , −C H
2 4
4
1
2
The yellow crystals melt at 155°C and are solu-
ble in aromatic and chlorinated hydrocarbons. A
strong absorption at 2047 cm−1 in the CO valence
no particularities and agree with values in litera-
ture.

120
D. Kruber et al. / Journal of Organometallic Chemistry 572 (1999) 117–123

D. Kruber et al. / Journal of Organometallic Chemistry 572 (1999) 117–123
121
Table 3
region of the IR spectrum of 2 in CsBr indicates the
change of 1 to a rhodium(III) complex [2,18].
˚
Selected bond lengths (A), angles (°) and endocyclic torsion angles (°)
¸¹¹¹¹¹¹¹¹º
for [{MeSnCH2CH2PPh2}2Rh(CO)Cl] (2)
˚
Bond lengths (A)
2.5. Molecular structure of
Rh–Sn(1)
Rh–Sn(2)
Rh–P(1)
2.592(1)
2.634(1)
2.370(1)
2.365(1)
1.942(4)
2.514(1)
2.159(5)
2.133(7)
2.430(1)
Sn(2)–C(3)
Sn(2)–C(7)
Sn(2)–Cl(3)
P(1)–C(2)
P(1)–C(8)
P(1)–C(14)
P(2)–C(4)
P(2)–C(20)
P(2)–C(26)
2.168(5)
2.135(5)
2.474(1)
1.856(5)
1.840(4)
1.837(4)
1.842(4)
1.835(5)
1.836(4)
¸¹¹¹¹¹¹¹¹¹º
[{Me(Cl)SnCH2CH2PPh2}2Rh(CO)Cl] (2)
Rh–P(2)
Rh–C(5)
Rh–Cl(1)
Sn(1)–C(1)
Sn(1)–C(6)
Sn(1)–Cl(2)
The solid state structure of 2 consists of discrete
monomeric units separated by normal van der Waals
contacts. An overall view of the molecule with the
atom-numbering scheme is shown in Fig. 2. Selected
bond lengths and angles are listed in Table 3. The main
feature of the structure of 2 are the two five-membered
P, Sn, and Rh containing heterocycles with a covalent
tin–rhodium bond and the short Sn(2)···Cl(1) contact
Bond angles (°)
P(1)–Rh–P(2)
178.8(1) C(6)–Sn(1)–Cl(2)
160.7(1) Rh–Sn(2)–C(3)
172.2(1) Rh–Sn(2)–C(7)
86.5(1) Rh–Sn(2)–Cl(3)
83.6(1) C(3)–Sn(2)–C(7)
96.5(1) Cl(3)–Sn(2)–Cl(3)
93.6(1) C(7)–Sn(2)–Cl(3)
95.3(1) Rh–P(1)–C(2)
83.5(1) Rh–P(1)–C(8)
75.1(1) Rh–P(1)–C(14)
92.4(1) C(2)–P(1)–C(8)
92.1(1) C(2)–P(1)–C(14)
88.7(1) C(8)–P(1)–C(14)
87.4(1) Rh-P(2)-C(4)
105.4(1) Rh-P(2)–C(20)
101.1(1) Rh–P(2)–C(26)
131.1(2) C(4)–P(2)–C(20)
105.8(1) C(4)–P(2)–C(26)
114.4(2) C(20)–P(2)–C(26)
99.1(1)
100.8(2)
102.1(1)
128.0(2)
115.4(1)
113.0(2)
98.4(1)
Sn(1)–Rh–Cl(1)
Sn(2)–Rh–C(5)
Sn(1)–Rh–Sn(2)
Sn(1)–Rh–P(1)
Sn(1)–Rh–P(2)
Sn(1)–Rh–C(5)
Sn(2)–Rh–P(1)
Sn(2)–Rh–P(2)
Sn(2)–Rh–Cl(1)
P(1)–Rh–C(5)
P(1)–Rh–Cl(1)
P(2)–Rh–C(5)
P(2)–Rh–Cl(1)
C(5)-Rh-Cl(1)
Rh–Sn(1)–C(1)
Rh–Sn(1)–C(6)
Rh–Sn(1)–Cl(2)
C(1)–Sn(1)–C(6)
C(1)–Sn(1)–Cl(2)
˚
˚
of 3.140(3) A (sum of the van der Waals radii: 3.85 A
[15]). The rhodium atom is situated in an octahedral
ligand sphere. The two phosphorus atoms are trans and
the tin atoms are cis to one another. The octahedron is
distorted at the Cl(1) edge by the Cl(1)···Sn(2) interac-
tion (Cl(1)–Rh–Sn(2) 75.1(1)°, Cl(1)–Rh–C(5)
105.4(1)°, Cl(1)–Rh–Sn(1) 160.7°(1)) and by the P–
Rh–Sn angle depression as result of the chelate ring
formation (P(1)–Rh–Sn(1) 83.6(1)°, P(2)–Rh–Sn(2)
83.5(1)°). The Sn–Rh bond lengths agree with values
described in the literature [16,17]. Due to the higher
trans influence of the CO ligand compared with that of
96.5(2)
114.2(2)
113.5(1)
117.2(1)
102.6(2)
105.2(2)
102.6(2)
113.5(2)
116.4(1)
114.6(1)
106.1(2)
102.9(2)
101.7(2)
˚
the Cl ligand the Rh–Sn(2) distance is with 2.634(1) A
sligthly longer than the Rh–Sn(1) bond length (2.592(1)
˚
A). Both the two phosphorus and the two tin atoms
exhibit a tetrahedral coordination, but, the deviation
from the ideal geometry is in case of the tin atoms
higher.
The five-membered chelate rings show an envelope
conformation. Sn, P, Rh and one C atom nearly form
a plane, and one ring is puckered at the C(1) and the
other one at the C(4) atom.
Torsion angles (°)
Rh–P(1)–C(2)–C(1)
P(1)–C(2)–C(1)–Sn(1) −50.1(4) P(2)–C(4)–C(3)–Sn(2) −41.9(4)
C(2)–C(1)–Sn(1)–Rh
C(1)–Sn(1)–Rh–P(1) −16.5(1) C(3)–Sn(2)–Rh–P(2)
Sn(1)–Rh–P(1)–C(2)
36.6(4) Rh–P(2)–C(4)–C(3)
44.8(4)
41.6(3) C(4)–C(3)–Sn(2)–Rh
22.3(3)
1.4(1)
−4.9(2) Sn(2)–Rh–P(2)–C(4) −21.2(2)
2.6. NMR spectroscopy of 2
The NMR data in Table 2 indicate that the structure
of 2 in solution is identical with that in the solid state.
Furthermore, the molecular geometry causes the chemi-
cal nonequivalence both of the two tin and phosphorus
atoms and also of the two tin methyl groups and the
eight methylene protons in the chelate rings. Because of
the proportion of only 8.58% for the NMR active 119Sn
isotope (see Section 2.3) three isotopomers of 2 with the
spin systems ABX, ABLX, and ABMX (A, B=31P,
L=119Sn(1), M=119Sn(2), X=103Rh) exist. Therefore,
the main signals in the 31P-NMR spectrum which are
doubled by the P–Rh coupling represent the AB part
of the ABX spin system (l: 54.8 ppm, J(31P103Rh)=
1
92.5 Hz; l: 63.9 ppm, 1J(31P103Rh)=90.1 Hz). The
decrease of the 1J(31P103Rh) coupling constant for 2
compared with 1 demonstrates the increase in the oxi-
¸¹¹¹¹¹¹¹¹º
Fig. 2. Molecular structure of [{MeSnCH2CH2PPh2}2Rh(CO)Cl] (2)
with the atom-labeling scheme. Hydrogen atoms and the solvent
molecule (C6H6) are omitted for clarity.

122
D. Kruber et al. / Journal of Organometallic Chemistry 572 (1999) 117–123
dation state from Rh(I) to Rh(III) [18]. The 119Sn
satellite signals in the 31P-NMR spectrum represent
the AB part of the ABLX and the ABMX spin sys-
tems mentioned above. At the present stage of our
studies an assignment of the 31P-NMR signals is not
possible.
3. Experimental
All manipulations were performed under dry argon.
Elemental analyses were carried out at the Microana-
lytical Laboratory of the Chemical Department. In-
frared spectra were measured on a Specord 75 IR
(CsBr). The NMR spectra were recorded on Gemini
200 (Varian) or Unity 500 (Varian) spectrometers. Sol-
vent signals (1H, 13C), Me4Sn (119Sn) and 85% H3PO4
(31P) were used as references. The NMR spectra simu-
lations were performed with the program PERCH
[21]. The molecular weight determination of 1 was
performed in benzene at 45°C (concentration=0.01
mol l−1) using a Knauer osmometer.
The 119Sn-NMR spectrum exhibits a multiplet at
249.7 ppm and a virtual triplet at 319.4 ppm. Both
signals are doubled by Sn–Rh coupling. The assign-
ment of the two 119Sn-NMR signals is based on the
different trans influence of the CO and the Cl ligand.
With respect to the higher trans influence of CO (see
1
Section 2.2) the J(119Sn(2)103Rh) coupling constant of
1
221.9 Hz is 110 Hz smaller than the J(119Sn(1)103Rh)
coupling. Therefore, the high-field 119Sn-NMR signal
at 249.7 ppm can be assigned to the Sn(2) atom and
the signal at 319.4 ppm to the Sn(1) atom. The low-
field position of the latter signal is also in agreement
with the high electronegativity of the Cl atom in the
trans position. Each 119Sn nucleus couples with both
phosphorus nuclei, but, in a different way. The
2J(119SnRh31P) is the one coupling the other one
nJ(119Sn, 31P) represents the sum of the two contribu-
3.1. [{Me2(Cl)SnCH2CH2PPh2}2Rh(CO)Cl] (1)
Solutions of [Rh(CO)2Cl]2 (300 mg, 0.77 mmol) and
Me2(Cl)SnCH2CH2PPh2 [3] (613 mg, 1.54 mmol) in
benzene (in each case 10 ml) are dropped simulta-
neously in pure benzene (50 ml) and the mixture is
stirred for 2 h to give a light yellow solution. During
the reaction the equivalent amount of CO (35 ml) is
released. After evaporation of the solvent the residue
is washed with pentane and dried in vacuo. 1 is ob-
tained as a yellow fine-crystalline compound (1.4 g,
96%); m.p. 124–126°C.
2
3
tions ꢀ J(119SnRh31P)ꢀ and ꢀ J(119SnCC31P)ꢀ within the
chelate ring. The coupling constants are determined by
computer simulation using the 119Sn-NMR spectrum
and the satellite part of the 31P-NMR spectrum. As
C33H40Cl3OP2RhSn2 (961.3): anal. (exp./calc.) C,
n
mentioned above an assignment of the J(119Sn, 31P)
41.51/41.23; H, 4.22/4.19; IR (CsBr, cm−1): 1975
coupling constants to a certain phosphorus atom is
not possible.
1
2
(CO). H-NMR (C6H6): l 0.56 (s, 6H, SnCH3, J(H,
Sn) 60.2 Hz); 1.43 (m, 4H, SnCH2); 2.84 (m, 4H,
The significant down field shift both of the 31P and
the 119Sn-NMR signals is due to the fact that these
atoms are included in a five-membered ring (‘ring ef-
fect’ of chemical shifts [19]). We have observed the
3
PCH2, J(H, Sn) 70 Hz); 6.99–7.68 (m, 20H, PC6H5)
ppm.
¸¹¹¹¹¹¹¹¹¹º
3.2. [{Me(Cl)SnCH2CH2PPh2}2Rh(CO)Cl] (2)
same effect for the bicyclic platinum complex
¸¹¹¹¹¹¹¹º
[{Me2SnCH2CH2PPh2}2Pt] [4].
A solution of 1 (1.0 g, 1.04 mmol) in toluene (50 ml)
was heated under stirring for 2 days whereby it slowly
turned from yellow to orange. The solvent was removed
and the yellow residue recrystallized from CH2Cl2/hex-
ane giving pure 2 (560 mg, 61%); m.p. 155°C.
The values of 211 and 224 Hz, respectively, for the
nJ(H, Sn) coupling constant for two of the four PCH2-
protons in the chelate rings of 2 are remarkably high.
Our knowledge about the mechanism of the trans-
formation of 1 into 2 is only vague. Certainly, the first
step is the intramolecular oxidative addition of the
Sn–C(Me) bond of one ligand to the Rh(I) centre of
1. Efforts to detect the resulting intermediate complex
failed. The higher reactivity of a Sn–C bond com-
pared with a Sn–Cl bond in oxidative additions of
triorganotin halides also is described for the reaction
of R3SnCl with Pd0 and Pt0 complexes [20]. The in-
tramolecular rearrangement of the intermediate com-
plex to 2 by demethylation both of the Rh atom and
the tin atom of the second ligand is accompanied by
the formation of methane and ethylene in a molar
ratio of 2:1. This could be proved by gas-chromato-
graphic investigation of the reaction.
C31H34Cl3OP2RhSn2 (931.2): anal. (exp./calc.) C,
40.53/39.98; H 4.53 /3.68; Cl 11.42/12.03; IR (CsBr,
cm−1): 2047 (CO). 1H-NMR (CD2Cl2): l −0.28 (s,
2
3H, SnCH3, J(H, Sn) 56.8 Hz); 0.05 (s, 3H, SnCH3,
2J(H, Sn) 56.5 Hz); 1.46 (m, 1H, SnCH2); 1.84 (m, 2H,
SnCH2); 1.92 (m, 1H, SnCH2); 2.35 (m, 1H, PCH2);
3
2,58 (m, 1H, PCH2); 2.96 (m, 1H, PCH2, J(H, Sn) 211
3
Hz); 3.60 (m, 1H, PCH2, J(H, Sn) 224 Hz); 7.37–8.20
(m, 20H, PC6H5) ppm.
3.3. Crystallographic studies
Crystal data and details of the data collection and
refinement of 1 and 2 are summarized in Table 4.

D. Kruber et al. / Journal of Organometallic Chemistry 572 (1999) 117–123
123
Table 4
Acknowledgements
Crystal data and details of data collection and refinement for 1 and
2
The authors thank the Deutsche Forschungsgemein-
schaft and the Fonds der Chemischen Industrie for
financial support.
1
2
Formula
Formula weight
C33H40Cl3OP2RhSn2
961.23
C
970.22
34H37OCl3RhSn2
(g mol−1
)
References
Space group
P21/c
P21/n
Temperature
240 K
r.t.
[1] H. Weichmann, G. Quell, A. Tzschach, Z. Anorg. Allg. Chem.
462 (1980) 7.
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11 (1992) 3163.
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Cryst. C54 (1998) 333.
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W.F.A. Wijsmuller, D.M. Grove, W.J.J. Smeets, A.L. Spek, J.
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[14] U. Kolb, M. Dra¨ger, B. Jousseaume, Organometallics 10 (1991)
2737.
Lattice parameters
˚
a (A)
18.590(10)
11.514(3)
18.812(8)
107.66(5)
3837(3)
4
1.664
4.22–52.30
−23 to 23; −12 to −16 to 16; −12
14; −22 to23
24131
13.521(2)
10.499(1)
25.761(2)
91.574(13)
3655.4(8)
4
˚
b (A)
˚
c (A)
i (°)
Cell volume (A )
3
˚
Formula units/unit cell
Dcalc. (g cm−1
2q Range (°)
)
1.763
4.18–51.74
Range of h, k, l
to 12; −31 to 31
26217
6804
Reflections measured
Reflections unique
Reflections observed
(Io]2.0|(Io))
7488
5147
Rint
0.0611
7488/522
0.922
0.0717
6804/520
1.075
0.0396/0.0923
0.0302/0.0746
Data/parameters
Goodness-of-fit (F2)
R1/wR2 (F2) (all data) 0.0615/0.0691
R1/wR2 (F2)
0.0329/0.0621
(Io]2.0|(Io))
Min./max. residual
−0.388/0.745
−0.754/1.327
electron density
[15] A. Bondi, J. Phys. Chem. 68 (1964) 441.
[16] H. Werner, O. Gevert, P. Haquette, Organometallics 16 (1997)
803.
−3
˚
(e A
)
[17] L. Carlton, R. Weber, D.C. Levendis, Inorg. Chem. 37 (1998)
1264.
[18] D.L. Egglestone, M.C. Baird, C.J.L. Lock, G. Turner, J. Chem.
Soc., Dalton Trans. (1977) 1576.
[19] P.E. Garrou, Chem. Rev. 81 (1981) 229.
[20] C. Eaborn, A. Pidcock, B.R. Steele, J. Chem. Soc., Dalton
Trans. (1976) 767.
Intensities were collected on a STOE IPDS diffractome-
ter using Mo–Kh radiation (u=0.71073 A). Final lat-
˚
tice parameter were obtained from a least square
refinement using 5000 reflections. The structures were
solved by direct methods using the program SHELXS-
86 [22]. The full-matrix least square structure refine-
ment was performed with the program SHELXL-93
[23]. All non-H atoms were refined anisotropically.
Figures were drawn with the program DIAMOND 2.0
[24].
[21] PERCH, NMR Software, Version 3/98, © University of Kuopio,
Finland.
[22] G.M. Sheldrick, SHELXS-86, Program for the solution of crys-
tal structures, University of Go¨ttingen, Germany (1986).
[23] G.M. Sheldrick, SHELXL-93, Program for the refinement of
crystal structures, University of Go¨ttingen, Germany (1993).
[24] K. Brandenburg, DIAMOND 2.0,Visual crystal structure infor-
mation system, crystal impact, Bonn, Germany (1998).
.