Ytterbium and samarium bis(diphosphanylamides): Syntheses and structures of lanthanide complexes having two {(Ph2P)2N}- ligands in the coordination sphere

Article abstract of DOI:10.1021/ic049437o

Bis(diphosphanylamide) complexes of the lanthanides have been sythesized. Two approaches to obtain these compounds are shown. Reaction of YbCl₃ with a slight excess of [K(THF)_n][N(PPh₂)₂] gives [{(Ph₂P)₂N}₂YbCl-(THF)₂], which can be further reacted with K(C₅Me₅) to give the corresponding pentamethylcyclopentadienyl complex [{(Ph₂P) ₂N}₂Yb(C₅Me₅)]. In a second approach to bis(diphosphanylamide) complexes of the lanthanides, Na(C₅H ₅) was treated with SMCl₃ to generate [(C ₅H₅)SmCl₂(THF)₃] in situ. Further reaction with 2 equiv of [K(THF)_n][N(PPh₂)₂] gave the desired complex [{(Ph₂P)₂N}₂Sm(C ₅H₅)(THF)].

Full text of DOI:10.1021/ic049437o

Inorg. Chem. 2004, 43, 4903−4906
Ytterbium and Samarium Bis(diphosphanylamides): Syntheses and
Structures of Lanthanide Complexes Having Two {(Ph2P)2N}- Ligands
in the Coordination Sphere
Michael T. Gamer and Peter W. Roesky*
Institut fu¨r Chemie, Freie UniVersita¨t Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany
Received April 30, 2004
Bis(diphosphanylamide) complexes of the lanthanides have been sythesized. Two approaches to obtain these
compounds are shown. Reaction of YbCl3 with a slight excess of [K(THF)n][N(PPh2)2] gives [{(Ph2P)2N}2YbCl-
(THF)2], which can be further reacted with K(C Me5) to give the corresponding pentamethylcyclopentadienyl complex
5
[{(Ph2P)2N}2Yb(C Me5)]. In a second approach to bis(diphosphanylamide) complexes of the lanthanides, Na(C H )
5
5 5
was treated with SmCl3 to generate [(C H )SmCl2(THF)3] in situ. Further reaction with 2 equiv of [K(THF)n][N(PPh2)2]
5
5
gave the desired complex [{(Ph2P)2N}2Sm(C H )(THF)].
5
5
Introduction
of correlations of theoretical and experimental molecular
weights as well as polydispersities were observed depending
on the nature of Ln. Furthermore, monosubstituted diphos-
phanylamide complexes, [{(Ph2P)2N}LnCl2(THF)3], of
yttrium and the lanthanides were obtained by reacting
[K(THF)n][N(PPh2)2] (n ) 1.25, 1.5) with anhydrous yttrium
or lanthanide trichlorides.6 The single-crystal X-ray structures
of these complexes always show an η2-coordination of the
ligand via the nitrogen and one phosphorus atom. In solution,
a dynamic behavior of the ligand is observed, which is caused
by the rapid exchange of the two different phosphorus atoms.
The mono- and trisubstituted complexes [{(Ph2P)2N}LnCl2-
(THF)3] and [Ln{N(PPh2)2}3], respectively, were easily
obtained in high yields by reacting [K(THF)n][N(PPh2)2] and
LnCl3 in the appropriate ratio. However, the missing links
between these complexes, i.e., obtaining the bis(diphosphan-
ylamide) complexes of the lanthanides of general composi-
tion [{(Ph2P)2N}2LnCl(THF)x], turned out to be more difficult
to obtain. In this article, we report the first results in this
area.
Recently, there has been a significant research effort in
d- and f-block transition metal chemistry to find, in addition
to the well-established cyclopentadienyl ligand,1 new ancil-
lary ligands for stabilizing highly reactive metal centers. In
this regard, one approach among others is the use of
phosphines with P-N bonds.2 Recently, we have introduced
the well-known monophosphanylamide, (Ph2PNPh)-,3 and
diphosphanylamide, {(Ph2P)2N}-,4-6 as ligands in lanthanide
chemistry. Depending on the steric demand of the ligand,
either metalate complexes of composition [Li(THF)4][(Ph2-
PNPh)4Ln] (Ln ) Y, Yb, Lu)3 or the homoleptic compounds
[Ln{N(PPh2)2}3] (Ln ) Y, La, Nd, Er)4 can be obtained.
The latter complexes were used as catalysts for the poly-
merization of ꢀ-caprolactone. Significant differences in terms
* To whom correspondence should be addressed. E-mail: roesky@
chemie.fu-berlin.de.
(1) Reviews: (a) Edelmann, F. T. Angew. Chem. 1995, 107, 2647-2669;
Angew. Chem., Int. Ed. Engl. 1995, 34, 2466-2488. (b) Edelmann,
F. T.; Freckmann, D. M. M.; Schumann, H. Chem. ReV. 2002, 102,
1851-1896.
(2) Balakrishna, M. S.; Sreenivasa Reddy, V.; Krishnamurthy, S. S.; Nixon,
J. F.; Burckett St. Laurent, J. C. T. R. Coord. Chem. ReV. 1994, 129,
1-90.
Experimental Section
General. All manipulations of air-sensitive materials were
performed with the rigorous exclusion of oxygen and moisture in
flame-dried Schlenk-type glassware either on a dual-manifold
Schlenk line, interfaced to a high-vacuum (10-4 Torr) line, or in
an argon-filled M. Braun glovebox. Ether solvents (tetrahydrofuran
and ethyl ether) were predried over Na wire and distilled under
nitrogen from Na/K benzophenone ketyl prior to use. Hydrocarbon
solvents (toluene and n-pentane) were distilled under nitrogen from
(3) (a) Wetzel, T. G.; Dehnen, S.; Roesky, P. W. Angew. Chem. 1999,
111, 1155-1158; Angew. Chem., Int. Ed. Engl. 1999, 38, 1086-1088.
(b) Wingerter, S.; Pfeiffer, M.; Baier, F.; Stey, T.; Stalke, D. Z. Anorg.
Allg. Chem. 2000, 626, 1121-1130.
(4) Roesky, P. W.; Gamer, M. T.; Puchner, M.; Greiner, A. Chem. Eur.
J. 2002, 8, 5265-5271.
(5) Gamer, M. T.; Canseco-Melchor, G.; Roesky, P. W. Z. Anorg. Allg.
Chem. 2003, 629, 2113-2116.
(6) Roesky, P. W.; Gamer, M. T.; Marinos, N. Chem. Eur. J. 2004, 10,
in press.
10.1021/ic049437o CCC: $27.50 © 2004 American Chemical Society
Published on Web 07/09/2004
Inorganic Chemistry, Vol. 43, No. 16, 2004 4903

Gamer and Roesky
Table 1. Crystallographic Details of [{(Ph2P)2N}2Yb(C5Me5)] (2)a
LiAlH4. All solvents for vacuum line manipulations were stored in
vacuo over LiAlH4 in resealable flasks. Deuterated solvents were
obtained from Chemotrade Chemiehandelsgesellschaft mbH (all
g99 atom % D) and were dried, degassed, and stored in vacuo
over Na/K alloy in resealable flasks. NMR spectra were recorded
on a JNM-LA 400 FT-NMR spectrometer. Chemical shifts are
referenced to internal solvent resonances and are reported relative
to tetramethylsilane and 85% phosphoric acid (31P NMR). Mass
spectra were recorded at 70 eV on a Varian MAT 711 instrument.
Elemental analyses were performed at the microanalytical laboratory
of the Institute of Inorganic Chemistry at University of Karlsruhe,
Germany. YbCl3,7 K(C5Me5),8 Na(C5H5),9 and [K(THF)n][N(PPh2)2]
(n ) 1.25, 1.5)4 were prepared according to literature procedures.
[{(Ph2P)2N}2YbCl(THF)2] (1). THF (20 mL) was condensed
at -196 °C onto a mixture of 0.909 g (1.83 mmol) of [K(THF)n]-
[N(PPh2)2] and 0.250 g (0.89 mmol) of YbCl3, and the mixture
was stirred for 18 h at room temperature. The mixture was filtered,
and the solvent removed in vacuo. The product was recrystallized
from THF/n-pentane (1:2). Yield: 0.473 g (47%), orange-red
crystals. IR [KBr (cm-1)]: 3050 (w, νCdC-H), 2997 (m, νC-
H), 2980 (m, νC-H), 1583 (w, νCdC), 1478 (m), 1432 (s), 1093
(m), 1015 (m, νPC), 917 (m), 898 (m), 696 (m). C56H56ClN2O2P4-
Yb (1121.40): calcd. C 59.98, H 5.03, N 2.50; found C 59.91, H
4.89, N 2.31.
2‚(2THF)
formula
C58H55N2P4Yb
2153.92
formula weight
space group
a, Å
b, Å
c, Å
P21/c (no. 14)
10.916(2)
21.288(4)
21.608(4)
93.33(3)
â, deg
V, Å3
5013(2)
Z
4
density (g/cm3)
radiation
1.427
Mo KR (λ ) 0.71073 Å)
2.033
none
36499
9994 (Rint ) 0.0510)
9262
9994, 591
1.175
0.0226, 0.0708
µ, mm-1
absorption correction
reflections collected
unique reflections
observed reflections
data, parameters
GOF on F2
R1,b wR2c
a All data collected at 203 K. b R1 ) ∑||Fo| - |Fc||/∑|Fo|. c wR2 )
{∑[w(Fo - Fc )2]/∑[w(Fo )2]}1/2
.
2
2
2
All structures were solved by the Patterson method (SHELXS-
9710). The remaining non-hydrogen atoms were located from
successive difference Fourier map calculations. The refinements
were carried out with the program SHELXL-9711 by using the full-
matrix least-squares techniques on F, minimizing the function (Fo
[{(Ph2P)2N}2Yb(C5Me5)] (2). THF (20 mL) was condensed at
-196 °C onto a mixture of 0.241 g (0.21 mmol) of 1 and 0.041 g
(0.24 mmol) of K(C5Me5). The mixture was refluxed for 6 h at
room temperature, filtered, and the solvent removed in vacuo. The
product was recrystallized from THF/n-pentane (1:2). Yield: 0.096
g (42%), dark red crystals. C58H55N2P4Yb (1076.96): calcd. C
64.68, H 5.15, N 2.60; found C 64.28, H 4.87, N 2.25.
2
2
- Fc)2, where the weight is defined as 4Fo /2(Fo ) and Fo and Fc
are the observed and calculated structure factor amplitudes,
respectively.
Because of twinning problems, only the structure of compound
2 was fully refined. In the final cycles of each refinement, all non-
hydrogen atoms were assigned anisotropic temperature factors.
Carbon-bound hydrogen atom positions were calculated, and the
hydrogen atoms were allowed to ride on the carbons to which they
are bonded assuming a C-H bond length of 0.95 Å. The hydrogen
atom contributions were calculated but not refined. The final values
of refinement parameters are given in Table 1. The locations of
the largest peaks in the final difference Fourier map calculation as
well as the magnitude of the residual electron densities in each
case were of no chemical significance. Positional parameters,
hydrogen atom parameters, thermal parameters, bond distances, and
angles have been deposited as Supporting Information. Crystal-
lographic data (excluding structure factors) for the structures
reported in this paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication no.
CCDC-237447. Copies of the data can be obtained free of charge
upon application to CCDC, 12 Union Road, Cambridge CB21EZ,
U.K. (fax, +(44)1223-336-033; e-mail, deposit@ccdc.cam.ac.uk).
[{(Ph2P)2N}2Sm(C5H5)(THF)] (3). THF (20 mL) was condensed
at -196 °C onto a mixture of 0.041 g (0.47 mmol) of Na(C5H5)
and 0.120 g (0.47 mmol) of SmCl3. The mixture was stirred for 6
h at room temperature, and the solvent was removed in vacuo.
[K(THF)n][N(PPh2)2] (0.466 g, 0.94 mmol) was added to the
remaining residue, and the mixture was stirred for 18 h at room
temperature. The suspension was filtered, and the solvent was
removed in vacuo. The product was recrystallized from THF/n-
pentane (1:2). Yield: 0.165 g (33%), red crystals. IR [KBr (cm-1)]:
3061 (w, νCdC-H), 3051 (m), 1582 (w, νCdC), 1477 (m), 1431
(s), 1091 (m), 1015 (m, νPC), 920 (s), 781 (m), 739 (m), 700 (m),
1
666 (m). H NMR (d8-THF, 400 MHz, 25 °C): δ 1.74-1.79 (m,
4H, THF), 3.58-3.63 (m, 4H, THF), 7.00-7.10 (m, 16H, Ph),
7.12-7.23 (m, 8H, Ph), 7.70 (br, 16H, Ph), 7.88 (br, 5H, C5H5).
13C{1H} NMR (d8-THF, 100.4 MHz, 25 °C): δ 26.4 (THF), 68.2
(THF), 107.8 (C5H5), 128.4-128.7 (m, Ph), 133.3-133.5 (m, Ph),
141.7 (Ph). 31P{1H} NMR (d8-THF, 161.7 MHz, 25 °C): δ -58.0
(br). C57H53N2OP4Sm (1056.24): calcd. C 64.81, H 5.06, N 2.65;
found C 65.03, H 5.29, N 2.33.
Results and Discussion
Reaction of [K(THF)n][N(PPh2)2] with anhydrous ytter-
bium trichloride in THF in a 2:1 molar ratio does not lead
selectively to a product of composition [{(Ph2P)2N}2YbCl-
(THF)2] (1). Usually, traces of the homoleptic complex [Yb-
{N(PPh2)2}3] and [{(Ph2P)2N}YbCl2(THF)3] are also formed
during the course of the reaction. Recrystallization of the
crude product does not yield pure 1 but instead increases
the ratio of the less-soluble compound [{(Ph2P)2N}YbCl2-
X-ray Crystallographic Studies of 1-3. Crystals of 1-3 were
grown from hot THF. A suitable crystal was covered in mineral
oil (Aldrich) and mounted onto a glass fiber. The crystal was
transferred directly to the -73 °C cold N2 stream of a Stoe IPDS
diffractometer. Subsequent computations were carried out on an
Intel Pentium IV PC.
(7) Taylor, M. D.; Carter, C. P. J. Inorg. Nucl. Chem. 1962, 24, 387-
391.
(8) Watson, P. L.; Whitney, J. F.; Harlow R. L. Inorg. Chem. 1981, 3271-
(10) Sheldrick, G. M. SHELXS-97, Program of Crystal Structure Solu-
tion: University of Go¨ttingen: Go¨ttingen, Germany, 1997.
3278.
(9) Panda, T. K.; Gamer, M. T.; Roesky, P. W. Organometallics 2003,
22, 877-878.
(11) Sheldrick, G. M. SHELXL-97, Program of Crystal Structure Refine-
ment; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
4904 Inorganic Chemistry, Vol. 43, No. 16, 2004

Ytterbium and Samarium Bis(diphosphanylamides)
Figure 1. Solid-state structure of 1 showing the atom labeling scheme,
omitting hydrogen atoms.
Figure 2. Perspective ORTEP view of the molecular structure of 2.
Thermal ellipsoids are drawn to encompass 50% probability. Hydrogen
atoms are omitted for clarity.
Scheme 1
Table 2. Selected Bond Lengths (Å) and Angles (deg) of
[{(Ph2P)2N}2Yb(C5Me5)] (2)a
Bond Lengths (Å)
N1-P1
N2-Yb
P1-Yb
P3-Yb
N1-Yb
Cg-Yb
N1-P2
N2-P3
N2-P4
1.671(2)
2.251(2)
2.7844(9)
2.7146(7)
2.254(2)
2.300(8)
1.724(2)
1.664(2)
1.722(2)
Bond Angles (deg)
N1-Yb-N2
N1-Yb-P1
N1-Yb-P3
N2-Yb-P1
N2-Yb-P3
Cg-Yb-N1
Cg-Yb-N2
Cg-Yb-P1
Cg-Yb-P3
P1-N1-Yb
P2-N1-Yb
P1-N1-P2
P3-N2-Yb
P4-N2-Yb
P3-N2-P4
119.34(7)
36.86(6)
106.32(6)
99.49(5)
(THF)3]. In contrast, by running the reaction with a slight
excess of [K(THF)n][N(PPh2)2], only 1 and [Yb{N(PPh2)2}3]
are formed. In this case, 1 can be obtained after recrystal-
lization as the analytically pure product (Scheme 1). The
new complex has been characterized by IR spectroscopy and
elemental analysis. The structure of 1 in the solid state was
confirmed by single-crystal X-ray diffraction (Figure 1).
Compound 1 crystallizes in the monoclinic space group P21
having two molecules of 1 in the unit cell. The metal atoms
are surrounded by seven ligands in a distorted pentagonal
biypramidal arrangement in which two THF molecules are
located in the apex. As observed in the homoleptic complexes
[Ln{N(PPh2)2}3]4 and the monosubstituted complexes
[{(Ph2P)2N}LnCl2(THF)3],5,6 the diphosphanylamide ligand
in 1 is η2-coordinated via the nitrogen and one phosphorus
atom. Thus, one of the phosphorus atoms of the ligand binds
to the ytterbium center, whereas the other phosphorus atom
is bent away. The structure of compound 1 was solved as a
racemic twin but could not be fully refined. Because the
quality of the refinement is low, only the lattice constants
but no detailed discussion is presented, although the overall
structure of the molecule was clearly established.12
37.71(6)
122.82(1)
117.38(1)
130.72(1)
118.55(1)
89.09(10)
149.24(12)
120.92(12)
86.44(9)
142.76(11)
127.62(12)
a Cg ) C5Me5-ring centroid.
elemental analysis, and the solid-state structure was estab-
lished by single-crystal X-ray diffraction (Figure 2). Data
collection parameters and selected bond lengths and angles
are reported in Tables 1 and 2, respectively. Compound 2
adopts a distorted square pyramidal conformation in the solid
state. This geometry is formed by the η5-coordinated
pentamethylcyclopentadienyl ring, which is located on top
of the pyramid, and two η2-{(Ph2P)2N}- ligands, which are
on the base. Thus, the ytterbium atom is 9-fold-coordinated
if η5-C5Me5 is considered as a pentadentate ligand. The Cg-
Yb distance [Cg-Yb 2.300(8) Å] and the C-Yb bond
lengths [avg 2.598(2) Å] are in the expected range (Cg )
C5Me5-ring centroid).13 In the {(Ph2P)2N}2Yb core structure,
which is roughly C2 symmetric, the N-Yb and P-Yb bond
distances are N1-Yb 2.254(2) Å, N2-Yb 2.251(2) Å, P1-
Yb 2.7844(9) Å, and P3-Yb 2.7146(7) Å. These distances
are shorter than those observed in [{(Ph2P)2N}LnCl2(THF)3]
[N-Yb 2.295(2) Å and P-Yb 2.8280(8) Å].6 The free
Treatment of complex 1 with an excess of K(C5Me5) in
THF, followed by crystallization from THF/n-pentane
(1:2), afforded the corresponding pentamethylcyclopentadi-
enyl complex [{(Ph2P)2N}2Yb(C5Me5)] (2) as dark red
crystals (Scheme 1). Compound 2 was characterized by
(12) Crystallographic data for [{(Ph2P)2N}2YbCl(THF)2] (1): C56H56-
ClN2O2P4Yb, fw ) 1121.40, monoclinic, space group P21, a ) 15.064-
(3) Å, b ) 12.672(3) Å, c ) 15.069(3) Å, â ) 95.42(3)°, V )
(13) Schumann, H.; Meese-Marktscheffel, J. A.; Esser, L. Chem. ReV. 1995,
95, 865-986.
2863.8(10) Å3, Z ) 2, F ) 1.300 g cm-3, µ ) 0.983 mm-1
.
Inorganic Chemistry, Vol. 43, No. 16, 2004 4905

Gamer and Roesky
Scheme 2
signals of the phenyl rings are split into three multiplets in
the range of δ 7.00-7.10 ppm, δ 7.12-7.23 ppm, and δ
7.70 ppm. In the 13C{1H} NMR spectrum, the signal of the
(C5H5)- ring is observed at δ 107.8 ppm. One broad signal
is seen at δ 58.0 ppm in the 31P{1H} NMR spectrum,
showing that the phosphorus atoms are chemically equivalent
in solution at room temperature. A similar dynamic behavior
is observed for all other {(Ph2P)2N}- lanthanide compounds.
As shown earlier,4 the {(Ph2P)2N}- ligand acts as hemilabile
ligand.17,18 Thus, the hard nitrogen atom always binds to the
lanthanide atom, whereas the phosphorus atoms, which are
weak Lewis bases, form only poor Lewis acid-base adducts
with the lanthanides and thus might easily be replaced by a
hard donor atom such as oxygen in a catalytic cycle.19
In contrast to compound 2, in 3, one additional equivalent
of THF is coordinated to the center metal, showing that the
metal center is not completely shielded by two η2-
{(Ph2P)2N}- ligands and the smaller (C5H5)- ligand. A
similar coordination of one molecule of THF was observed
in [(C5H5)3Sm(THF)],20 indicating that the steric demand of
the η2-{(Ph2P)2N}- ligand is somewhat similar to that of the
well-known cyclopentadienyl group.
electron pair of the nonbonded phosphorus atoms points away
from the ytterbium center. The P-N-P angles within the
η2-{(Ph2P)2N}- ligand are P1-N1-P2 120.92(12)° and P3-
N2-P4 127.62(12)°. Within the ligand, the P-N bond
distance varies. The phosphorus atom that binds to the
lanthanide atom is significantly closer located to the nitrogen
atom [N1-P1 1.671(2) Å, N1-P2 1.724(2) Å, N2-P3
1.664(2) Å, N2-P4 1.722(2) Å].
A different approach to obtain bis(diphosphanylamide)
complexes of the lanthanides is the reaction of LnCl3 with 1
equiv of an ancillary ligand, which leads to complexes of
general composition [RLnCl2]. In a second step, the remain-
ing two chlorine atoms can be replaced by two η2-
{(Ph2P)2N}- ligands. This reaction sequence can be per-
formed in a one-pot reaction (see Scheme 2). Thus, Na(C5H5)
was treated with SmCl3 to generate [(C5H5)SmCl2(THF)3]
in situ.14 Further reaction of [(C5H5)SmCl2(THF)3] with 2
equiv of [K(THF)n][N(PPh2)2] gave the desired complex
[{(Ph2P)2N}2Sm(C5H5)(THF)] (3) as small red crystals. The
solid-state structure of 3 was investigated by single-crystal
X-ray diffraction. The structure was solved in the monoclinic
space group Cc, but as a result of a twinning problem, no
satifactory refinement could be obtained.15
Summary
In summary, we have prepared bis(diphosphanylamide)
complexes of the lanthanides. Two approaches to obtain these
compounds were shown. In the first approach, YbCl3 was
reacted with a slight excess of [K(THF)n][N(PPh2)2] to give
the desired bis(diphosphanylamide) complex [{(Ph2P)2N}2-
YbCl(THF)2]. In the second approach, a complex of general
composition [RLnCl2] was obtained with the use of an
ancillary ligand. The remaining two chlorine atoms can be
selectively substituted in a second reaction step. By following
the second approach, the samarium complex [{(Ph2P)2N}2-
Sm(C5H5)(THF)] was prepared.
Acknowledgment. This work was supported by the
Deutsche Forschungsgemeinschaft (DFG Schwerpunktpro-
gramm 1166: Lanthanoidspezifische Funktionalita¨ten in
Moleku¨l und Material) and the Fonds der Chemischen
Industrie. Additionally, much generous support from Prof.
Dr. D. Fenske (Universita¨t Karlsruhe) is gratefully acknowl-
edged.
Compound 3 was characterized by elemental analysis, and
IR, 1H NMR, 13C NMR, and 31P NMR spectroscopies. As a
result of the paramagnetic influence of the samarium atom,
1
the H NMR resonances are broad and shifted over a wide
Supporting Information Available: X-ray crystallographic files
in CIF format for the structure determinations of 2. This material
is available free of charge via the Internet at http://pubs.acs.org.
range. Thus, the signals of the five-membered ring are low-
field-shifted (δ 7.88 ppm) compared to those of the starting
material Na(C5H5) (δ 5.60 ppm).9 A similar downfield shift
has been observed in other cyclopentadienyl Sm complexes
such as [Li(THF)4][(C5H5)2Sm(NPh2)2] (δ 8.25 ppm).16 The
IC049437O
(17) For the definition of hemilabile ligands: Jeffrey, J. C.; Rauchfuss, T.
B. Inorg. Chem. 1979, 18, 2568-2666.
(18) (a) Mahalakshmi, L.; Stalke, D. Struct. Bonding 2002, 103, 83-115.
(b) Baier, F.; Fei, Z.; Gornitzka, H.; Murso, A.; Neufeld, S.; Pfeiffer,
M.; Ru¨denauer, I.; Steiner, A.; Stey, T.; Stalke, D. J. Organomet.
Chem. 2002, 661, 111-127.
(19) Hemilabile ligands in catalysis: Jolly, P. W.; Wilke, G. In Applied
Homogeneous Catalysis with Organometallic Compounds; Cornils, B.,
Herrmann, W. A., Eds.; Wiley-VCH: Weinheim, Germany, 2002; pp
1024-1048.
(20) Deacon, G. B.; Koplick, A. J.; Tuong, T. D. Aust. J. Chem. 1984, 37,
517-525.
(14) Manastyrskyj, S.; Maginn, R. E.; Dubeck, M. Inorg. Chem. 1963, 2,
904-905.
(15) Crystallographic data for [{(Ph2P)2N}2Sm(C5H5)(THF)] (3): C57H53N2-
OP4Sm, fw ) 1056.24, monoclinic, space group Cc, a ) 10.844(2)
Å, b ) 43.838(9) Å, c ) 10.863(2) Å, â ) 104.74(3)°, V ) 4994(2)
Å3, Z ) 4, F ) 1.405 g cm-3, µ ) 0.721 mm-1. The structure was
solved by the Patterson and Fourier methods.
(16) Schumann, H.; Palamidis, E.; Loebel, J. J. Organomet. Chem. 1990,
390, 45-52.
4906 Inorganic Chemistry, Vol. 43, No. 16, 2004