A Cationic Bis(Phosphiniminomethanide) Europium(II) Complex

Article abstract of DOI:10.1021/om800989x

The ionic Eu(II) complex {CH(PPh₂NSiMe₃)₂} Eu(THF)₃]BPh₄ was synthesized via the salt elimination reaction of [{CH(PPh₂NSiMe₃)₂}Eu(fi-I)(THF)] ₂ and NaBPh

Full text of DOI:10.1021/om800989x

1266
Organometallics 2009, 28, 1266–1269
A Cationic Bis(phosphiniminomethanide) Europium(II) Complex
Michal Wiecko† and Peter W. Roesky*,‡
Institut fu¨r Chemie and Biochemie, Freie UniVersita¨t Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany,
and Institut fu¨r Anorganische Chemie, UniVersita¨t Karlsruhe, Engesserstrasse 15,
76128 Karlsruhe, Germany
ReceiVed October 14, 2008
n ) 5; Ln ) Eu, n ) 6);5 however, as recently reviewed by
Summary: The ionic Eu(II) complex [CH(PPh2NSiMe3)2}-
Eu(THF)3]BPh4 was synthesized Via the salt elimination reaction of
[{CH(PPh2NSiMe3)2}Eu(µ-I)(THF)]2 and NaBPh4 in CH2Cl2. Sub-
sequent reactions led to the Eu(II) compounds [{CH(PPh2-
NSiMe3)2}2Eu] and [{CH(PPh2NSiMe3)2}Eu(THF){N(PPh2)2}].
Junk,1c the attempted ligand exchange reactions of [(C6F5)Yb-
(THF)5]BPh4 with protic reagents in coordinating solvents
always resulted in the formation of the solvated dications
[Yb(THF)6][BPh4]2, [Yb([18]-crown-6)(pyridine)2][BPh4]2, and
[Yb([18]-crown-6)(NCMe)3][BPh4]2 respectively. In contrast, in
“noncoordinating” solvents such as toluene and benzene un-
solvated complexes such as [(C5Me5)Ln(µ-η6-Ph)2BPh2]6 (Ln
) Sm, Yb), [{(SiMe3)2N}Yb(THF)(µ-η6-Ph)(µ-η2-Ph)BPh2],7a
and [{(SiMe3)2N}Yb(µ-η6-Ph)2BPh2]7b are accessible via pro-
tolysis of the corresponding homoleptic compounds.
In recent years the coordination chemistry of organometallic
compounds of the rare earth elements containing a metal-
centered cation has attracted much attention.1,2 This interest has
been mostly fueled by the synthetic application of isolated or
intermediate cationic rare earth compounds in various polym-
erization reactions of organic monomers.2,3 In this context
weakly coordinating anions, in particular the borates BPh4- and
For several years now our group has been exploring monoan-
ionic N-donor ligands as an alternative to cyclopentadiene-based
systems. We used the bis(phosphiniminomethanide) {CH-
(PPh2NSiMe3)2}- as an ancillary ligand in rare earth8 and
alkaline earth metal chemistry, and several Ln(II) (Ln ) Eu,
Sm, Yb) compounds have already been reported by our
group.9,10 Now we are interested in using this ligand to stabilize
monocationic Ln(II) compounds in donor solvents. Herein we
report on the facile preparation of a rare monocationic Eu(II)
complex and its use in subsequent synthesis.
-
B(C6F5)4 or their derivatives, were used to induce charge
separation, increase the cationic character of the metal center,
and/or predetermine easily accessible coordination sites. While
the number of known cationic Ln(III) organyls is therefore
rapidly increasing, cationic complexes of the divalent lanthanides
remain rare. As first reported by Evans, monocationic complexes
-
of Sm(II) and Yb(II) with the BPh4 counteranion tend to
undergo ligand redistribution reactions, forming dicationic
species.4 Therefore, protonation of the amide ligand in [(η5-
C5Me5)Ln{N(SiMe3)2}(THF)2] (Ln ) Sm, Yb) with HNEt2BPh4
resulted in the formation of the fully solvated dications
[Ln(THF)n][BPh4]2 (Ln ) Yb, n ) 6; Ln ) Sm, n ) 7) and the
corresponding permethylmetallocenes [(η5-C5Me5)2Ln(THF)1,2].
Deacon and co-workers successfully prepared the perfluoro-
aryllanthanide(II) monocations [(C6F5)Ln(THF)n]+ (Ln ) Yb,
Results and Discussion
The ionic compound [{CH(PPh2NSiMe3)2}Eu(THF)3]BPh4
(1)wassynthesizedbyasaltmetathesisreactionof[{CH(PPh2NSi-
Me3)2}Eu(THF)(µ-I)]2 with NaBPh4, following the route shown
in Scheme 1. The reaction in CH2Cl2 resulted after 12 h in the
formation of a yellow powder, which gave compound 1 after
dissolution in THF.
The density of NaBPh411 is smaller than that of CH2Cl2 and
NaI;12 therefore, the progress of the reaction can be easily
monitored by its consumption. However, analogous reactions
with the metal centers Yb(II) and Sm(II) failed, presumably due
* To whom correspondence should be addressed. E-mail: roesky@
chemie.uni-karlsruhe.de.
† Freie Universita¨t Berlin.
‡ Universita¨t Karlsruhe.
(1) Reviews: (a) Arndt, S.; Okuda, J. AdV. Synth. Catal. 2005, 347, 339.
(b) Zeimentz, P. M.; Arndt, S.; Elvidge, B. R.; Okuda, J. Chem. ReV. 2006,
106, 2404. (c) Deacon, G. B.; Evans, D. J.; Forsyth, C. M.; Junk, P. C.
Coord. Chem. ReV. 2007, 251, 1699.
(2) Recent examples: (a) Robert, D.; Spaniol, T. P.; Okuda, J. Eur.
J. Inorg. Chem. 2008, 2801. (b) Tredget, C. S.; Clot, E.; Mountford, P.
Organometallics 2008, 27, 3458. (c) Robert, D.; Kondracka, M.; Okuda, J.
Dalton Trans. 2008, 2667. (d) Nishiura, M.; Mashiko, T.; Hou, Z. Chem.
Commun. 2008, 2019. (e) Zimmermann, M.; To¨rnroos, K. W.; Waymouth,
R. M.; Anwander, R. Organometallics 2008, 27, 4310. (f) Kramer, M. U.;
Robert, D.; Nakajima, Y.; Englert, U.; Spaniol, T. P.; Okuda, J. Eur. J. Inorg.
Chem. 2007, 665. (g) Hayes, P. G.; Piers, W. E.; Parvez, M. Chem. Eur. J.
2007, 13, 2632.
(3) For examples, see: (a) Li, X.; Nishiura, M.; Mori, K.; Mashiko, T.;
Hou, Z. Chem. Commun. 2007, 4137. (b) Li, S.; Miao, W.; Tang, T.; Cui,
D.; Chen, X.; Jing, X. J. Organomet. Chem. 2007, 692, 4943. (c) Luo, Y.;
Hou, Z. Organometallics 2006, 25, 6162. (d) Li, X.; Baldamus, J.; Nishiura,
M.; Tardif, O.; Hou, Z. Angew. Chem., Int. Ed. 2006, 45, 8184. (e) Bambirra,
S.; van Leusen, D.; Tazelaar, C. G. J.; Meetsma, A.; Hessen, B. Organo-
metallics 2007, 26, 1014. (f) Zhang, L.; Suzuki, T.; Luo, Y.; Nishiura, M.;
Hou, Z. Angew. Chem., Int. Ed. 2007, 46, 1909.
(5) Deacon, G. B.; Forsyth, C. M. Chem. Eur. J. 2004, 10, 1798.
(6) Evans, W. J.; Champagne, T. M.; Ziller, J. W. Organometallics 2007,
26, 1204.
(7) (a) Deacon, G. B.; Forsyth, C. M. Chem. Commun. 2002, 2522. (b)
Deacon, G. B.; Forsyth, C. M.; Junk, P. C. Eur. J. Inorg. Chem. 2005, 817.
(8) (a) Gamer, M. T.; Dehnen, S.; Roesky, P. W. Organometallics 2001,
20, 4230. (b) Zulys, A.; Panda, T. K.; Gamer, M. T.; Roesky, P. W. Chem.
Commun. 2004, 2584. (c) Zulys, A.; Panda, T. K.; Gamer, M. T.; Roesky,
P. W. Organometallics 2005, 24, 2197. (d) Gamer, M. T.; Roesky, P. W.;
Rasta¨tter, M.; Steffens, A.; Glanz, M. Chem. Eur. J. 2005, 11, 3165. (e)
Rasta¨tter, M.; Zulys, A.; Roesky, P. W. Chem. Commun. 2006, 874. (f)
Rasta¨tter, M.; Zulys, A.; Roesky, P. W. Chem. Eur. J. 2007, 13, 3606. (g)
Gamer, M. T.; Roesky, P. W.; Palard, I.; Le Hellaye, M.; Guillaume, S. M.
Organometallics 2007, 26, 651.
(9) Panda, T. K.; Zulys, A.; Gamer, M. T.; Roesky, P. W. J. Organomet.
Chem. 2005, 690, 5078.
(10) Wiecko, M.; Roesky, P. W.; Burlakov, V. V.; Spannenberg, A.
Eur. J. Inorg. Chem. 2007, 876.
(11) Arnott, S.; Abrahams, S. C. Acta Crystallogr. 1958, 11, 449.
(12) Sathe, N. V.; Phalnikar, N. L.; Bhide, B. V. J. Indian Chem. Soc.
1945, 22, 29.
(4) Evans, W. J.; Johnston, M. A.; Greci, M. A.; Gummersheimer, T. S.;
Ziller, J. W. Polyhedron 2003, 22, 119.
10.1021/om800989x CCC: $40.75
2009 American Chemical Society
Publication on Web 01/20/2009

Notes
Organometallics, Vol. 28, No. 4, 2009 1267
Scheme 1
Table 1. Crystallographic Details of 1 and 3
bis(phosphiniminomethanide) complexes of europium. The
Eu-N and Eu-C distances in compound 1 (Eu-N1 ) 2.579(3)
and Eu-N2 ) 2.592(3) Å, Eu-C1 ) 2.943(3) Å) are in range
similar to that for other 6-fold-coordinated bis(phosphinimi-
nomethanide) complexes of europium (e.g., in [{CH(PPh2NSi-
Me3)2}Eu(THF)(µ-I)]2 Eu-N1 ) 2.596(2) Å, Eu-N2 )
2.563(2)Å,andEu-C1)2.945(2)Åandin[{CH(PPh2NSiMe3)2}-
Eu{η2-N(PPh2)2)(THF)] Eu-N1 ) 2.539(4) Å, Eu-N2 )
2.579(4) Å, and Eu-C1 ) 2.878(4) Å).9 On the other hand,
the Eu-O distances to the coordinating THF molecules in
compound 1 (Eu-O1 ) 2.569(2), Eu-O2 ) 2.602(3), Eu-O3
) 2.522(3) Å; average Eu-O ) 2.565 Å) are even longer than
those in [{CH(PPh2NSiMe3)2}Eu(THF)(µ-I)]2 (Eu-O ) 2.479(2)
Å). We suggest that these observations are a result of steric
effects.
1 · THF
2 3 · (toluene)
formula
formula wt
space group
a (Å)
b (Å)
c (Å)
R (deg)
ꢀ (deg)
γ (deg)
V (Å3)
C71H91BEuN2O4P2Si2
1317.35
P1 (No. 2)
C131H164Eu2N8P8Si8
2627.10
P1 (No. 2)
j
j
11.5552(7)
16.4704(11)
17.8916(11)
89.858(5)
94.073(5)
95.634(5)
3380.1(4)
2
11.819(2)
15.421(3)
19.688(4)
75.96(3)
82.43(3)
79.30(3)
3406.5(11)
1
Z
Fcalcd (g/cm3)
radiation
1.294
1.281
Mo KR (λ ) 0.710 73 Å)
µ (mm-1
T (K)
)
1.059
1.125
150(2)
200(2)
abs cor
numerical
19 733
To investigate the synthetic utility of compound 1, we
performed two model reactions. The known complex [CH(PPh2-
NSiMe3)2}Eu{η2-N(PPh2)2)(THF)] (2)9 was obtained by the
reaction of compound 1 with K(THF){N(PPh2)2}15 in toluene
(Scheme 2). Moreover, reacting compound 1 with 1 equiv of
the potassium salt K{CH(PPh2NSiMe3)2}16 led to the homo-
leptic, THF-free compound [CH(PPh2NSiMe3)2}2Eu] (3) in
moderate yields (63%). Complex 3 was also accessible in a
higher yield by treatment of EuI2(THF)2 with 2 equiv of K{CH-
(PPh2NSiMe3)2} in THF (Scheme 2).
no. of collected rflns 26 239
no. of unique rflns
no. of obsd rflns
no. of data, params
R1
11 853 (Rint ) 0.0528) 11 542 (Rint ) 0.0670)
9442
9622
11 853, 743
0.0370
0.0718
0.963
11 542, 688
0.0509
0.1304
1.005
wR2
GOF
to their higher redox potential and decomposition in CH2Cl2
via redox processes.13 In all cases, in THF, toluene, or their
mixtures no reaction was observed. Compound 1 was character-
ized by standard analytical and spectroscopic techniques. As a
result of the strongly paramagnetic center metal, NMR spec-
troscopy is not very useful for a clear characterization of
bis(phosphinimino)methanide complexes of the divalent lan-
thanide europium.
Single crystals of 1 suitable for X-ray structure analysis were
obtained by layering a THF solution of the compound with
n-pentane. Data collection parameters and selected bond lengths
and angles are given in Table 1 and the caption of Figure 1,
respectively. Complex 1 crystallizes in the triclinic space group
Compound 3 has been characterized by standard analytical/
spectroscopic techniques. The spectral data of compound 3 are
more conclusive than for the ionic compound 1. In the 1H NMR
spectrum of compound 3 the hydrogen atom of the methine
group can be observed at δ 2.11 ppm. The 31P{1H} NMR shows
one singlet for the four equivalent phosphorus atoms at δ 532
ppm. Additionally we recorded high-resolution mass spectra to
confirm the composition of compound 3.
The solid-state structure of compound 3 was established by
X-ray techniques (Figure 2). As expected, due to the very similar
ionic radii of Eu2+ and Sm2+ (Eu2+ ) 1.20 Å and Sm2+ ) 1.22
Å for coordination number 7),17 the structure of compound 3
is related to those of the known samarium complexes
[{CH(PPh2NSiMe3)2}2Sm] and [{CH(PPh2NMes)2}2Sm] (Mes
) 2,4,6-Me3C6H3).18 Thus, the two {CH(PPh2NSiMe3)2}-
ligands coordinate asymmetrically via the nitrogen atoms in a
chelating fashion with long Eu-N (Eu-N1 ) 2.778(4) and
Eu-N4 ) 2.765(4) Å) and short Eu-N (Eu-N2 2.605(4) and
Eu-N3 2.602(4) Å) bond lengths for each ligand. Additionally
an overall 6-fold coordination of the metal center is achieved
by coordination of the methine carbon atoms. The Eu-Cmethine
distances in compound 3 (Eu-C1 ) 2.865(5), Eu-C32 )
2.880(5) Å) are significantly shorter than in the cation of
j
P1 with an additional THF molecule per ion pair remaining in
the crystal (Figure 1). In the solid state no close contacts between
cation and anion were observed, with the shortest distance
Eu · · · CBPh being approximately 6.70 Å.
The six-4membered ring formed by the {CH(PPh2NSiMe3)2}-
ligand and the Eu(II) center adopts a twist-boat conformation,
and the methine carbon and europium atoms are displaced from
the P2N2 plane. The observed coordination mode, having a long
C1-metal interaction which was discussed earlier, is very
common for bis(phosphiniminomethanide) complexes of the rare
earth metals.8 In contrast to other cationic rare earth complexes,
in which the bond distances are shorter than in their neutral
counterparts (e.g., in [(C6F5)Eu(THF)6]+ Eu-C ) 2.735(2) Å;5
in [(C6F5)2Eu(THF)5] Eu-C ) 2.822(2) Å14), we do not see
such an effect in compound 1 in comparison to neutral
(15) Roesky, P. W.; Gamer, M. T.; Puchner, M.; Greiner, A. Chem.
Eur. J. 2002, 8, 5265.
(16) Gamer, M. T.; Roesky, P. W. Z. Anorg. Allg. Chem. 2001, 627,
877.
(17) Shannon, R. D. Acta Cryst. 1976, A32, 751-760.
(18) Hill, M. S.; Hitchcock, P. B. Dalton Trans. 2003, 4570.
(13) E°(Ln3+/Ln2+) in H2O: Eu,-0.31 V; Yb,-1.05 V; Sm,-1.55 V:
Hollemann, A. F.; Wiberg, E. Lehrbuch der Anorganischen Chemie, 101st
ed.; De Gruyter: Berlin, 1995.
(14) Forsyth, C. M.; Deacon, G. B. Organometallics 2000, 19, 1205.

1268 Organometallics, Vol. 28, No. 4, 2009
Notes
Figure 1. Molecular structure of 1. Hydrogen atoms are omitted for clarity. Ellipsoids are drawn to encompass 30% probability. Selected
bond lengths (Å) and angles (deg): Eu-N1 ) 2.579(3), Eu-N2 ) 2.592(3), Eu-O1 ) 2.569(2), Eu-O2 ) 2.602(3), Eu-O3 ) 2.522(3),
Eu-C1 ) 2.943(3), N1-P1 ) 1.577(3), N1-Si1 ) 1.693(3), N2-P2 ) 1.595(3), N2-Si2 ) 1.713(3), C1-P1 ) 1.729(3), C1-P2 )
1.734(3); N1-P1-C1 ) 111.50(15), N2-P2-C1 ) 122.3(2), N1-Eu-N2 ) 85.49(8), P1-C1-P2 ) 129.9(2), O3-Eu-O1 ) 97.40(9),
O3-Eu-O2 ) 80.24(11), O1-Eu-O2 ) 76.07(9).
Scheme 2
and moisture in flame-dried Schlenk-type glassware either on a dual-
manifold Schlenk line, interfaced to a high-vacuum (10-3 Torr)
line, or in an argon-filled MBraun glovebox. THF was predried
over potassium and distilled under nitrogen from Na/K alloy
benzophenone ketyl prior to use. Hydrocarbon solvents (toluene
and n-pentane) were distilled under nitrogen from LiAlH4. All
solvents for vacuum-line manipulations were stored in vacuo over
LiAlH4 in resealable flasks. Deuterated solvents were obtained from
Chemotrade or Euriso-Top GmbH (99 atom % D). NMR spectra
were recorded on a Jeol JNM-LA 400 FT-NMR spectrometer.
Chemical shifts are referenced to internal solvent resonances and
are reported relative to tetramethylsilane. Raman spectra were
performed on a Bruker RFS 100. Elemental analyses were carried
out with an Elementar Vario EL III. Mass spectra were acquired
with a Finnigan MAT 711 mass spectrometer at an ionization
potential of 70 eV and were reported as mass/charge (m/e) with
percent relative abundance. [{CH(PPh2NSiMe3)2}Eu(THF)(µ-I)]2
was prepared following a literature procedure.9
compound 1 and also shorter than in the related Sm(II)
complexes (Sm-Cmethine ) 2.8991(15) and 2.8984(14) Å in
[{CH(PPh2NSiMe3)2}2Sm];10 Sm-Cmethine ) 2.900(5) and
2.877(5) Å in [{CH(PPh2NMes)2}2Sm]).18
Summary
In summary, we have prepared the bis(phosphinimi-
nomethanide) Eu(II) monocation [{CH(PPh2NSiMe3)2}Eu-
(THF)3]+. In the solid state the title compound showed no close
contacts between cation and anion. Further reaction of
[{CH(PPh2NSiMe3)2}Eu(THF)3]BPh4 with potassium reagents
resulted in the neutral Eu(II) compounds [{CH(PPh2-
NSiMe3)2}2Eu] and [{CH(PPh2NSiMe3)2}Eu(THF){N(PPh2)2}],
while KBPh4 is formed as a byproduct.
Experimental Section
General Considerations. All manipulations of air-sensitive
materials were performed with the rigorous exclusion of oxygen
[{CH(PPh2NSiMe3)2}Eu(THF)3]BPh4 (1). To a mixture of
[{CH(PPh2NSiMe3)2}Eu(THF)(µ-I)]2 (227 mg, 0.12 mmol) and

Notes
Organometallics, Vol. 28, No. 4, 2009 1269
residue suspended in toluene (15 mL). Filtration and removal of
the toluene yielded 445 mg of (86%) 3.
1H NMR (C6D6, 400 MHz, 21 °C): δ 0.26 (s, 36 H, SiMe3),
2.11 (br, 2 H, CH), 6.90-7.15 (m, 16 H, Ph), 7.65-7.75 (m, 24
H, Ph). 31P{1H} NMR (C6D6, 160.7 MHz, 21 °C): δ 532 ppm. MS
(EI, 240 °C): 1267 (M+, 4), 709 (M+ - CH(PPh2NSiMe3)2, 13),
+
543 (CH2(PPh2NSiMe3)2 - CH3, 100), 454 (14). Raman (solid):
613 (m), 784 (w), 999 (s), 1028 (m), 1103 (w), 1157 (w), 1572
(w), 1588 (m), 2895 (br), 2951 (br), 3057 (s) cm-1. Anal. Calcd
for C62H78N4P4Si4Eu (Mr ) 1267.51): C, 58.75; H, 6.20; N, 4.42.
Found: C, 58.75; H 5.76; N, 4.07.
X-ray Crystallographic Studies of 1 and 3. Crystals of 1 were
obtained from THF/n-pentane, and crystals of 3 were obtained from
toluene. A suitable crystal was covered in mineral oil (Aldrich)
and mounted onto a glass fiber. The crystal was transferred directly
to a cold N2 stream of a STOE IPDS 2T diffractometer. Subsequent
computations were carried out on a Intel Pentium IV PC or an Intel
Core2 Duo PC. All structures were solved by the Patterson method
(SHELXS-9719). The remaining non-hydrogen atoms were located
from successive difference Fourier map calculations. The refine-
ments were carried out by using full-matrix least-squares techniques
on F, minimizing the function (Fo - Fc),2 where the weight is
defined as 4Fo /2(Fo ) and Fo and Fc are the observed and calculated
structure factor amplitudes using the program SHELXL-97,20
respectively. Carbon-bound hydrogen atom positions were calcu-
lated. 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, and
bond distances and angles have been deposited as Supporting
Information. Crystallographic data (excluding structure factors) for
the structures reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary publica-
tion nos. CCDC-710924 (1) and CCDC-710925 (3). Copies of the
data can be obtained free of charge on application to the CCDC,
12 Union Road, Cambridge CB2 1EZ, U.K. (fax (+(44)1223-336-
033; e-mail deposit@ccdc.cam.ac.uk).
Figure 2. Molecular structure of 3. Hydrogen atoms are omitted
for clarity. Ellipsoids are drawn to encompass 30% probability.
Selected bond lengths (Å) and angles (deg): Eu-N1 ) 2.778(4),
Eu-N2 ) 2.605(4), Eu-N3 ) 2.602(4), Eu-N4 ) 2.765(4),
Eu-C1 ) 2.865(5), Eu-C32 ) 2.880(5), N1-P1 ) 1.592(4),
N2-P2 ) 1.577(5), N3-P3 ) 1.595(4), N4-P4 ) 1.576(5);
P1-C1-P2 ) 124.7(3), P3-C32-P4 ) 125.5(3), N2-Eu-N3
) 106.52(13), N3-Eu-N4 ) 85.70(12), N2-Eu-N4 ) 135.83(14),
N3-Eu-N1 ) 135.08(13), N2-Eu-N1 ) 85.49(13), N4-Eu-N1
) 115.77(12), C1-Eu-C32 ) 132.38(13).
2
2
NaBPh4 (83 mg, 0.26 mmol) was added CH2Cl2 (10 mL). The
mixture was stirred for 12 h at room temperature and filtered
through a glass frit. The solvent was removed in vacuo, and the
obtained yellow powder was dissolved in 3-5 mL of THF.
n-Pentane was layered on top of the solution, yielding 87 mg (28%)
of 1 as pale yellow crystals. 1H NMR (d8-THF, 400 MHz, 20 °C):
δ 0.08 (s, 18 H, SiMe3), 6.50-8.00 (m, 40 H, Ph). Raman (solid):
609 (m), 667 (w), 923 (w), 998 (s), 1029 (m), 1103 (w), 1581 (w),
2893 (br), 2950 (br), 3047 (s) cm-1
. Anal. Calcd for
C67H83BEuN2O3P2Si2 (Mr ) 1245.28): C, 64.62; H, 6.72. N, 2.25.
Found: C, 63.84; H, 6.51; N, 2.02.
[CH(PPh2NSiMe3)2}Eu{η2-N(PPh2)2)(THF)] (2). The synthesis
was performed following the route A to 3. Recrystallization of the
crude product from toluene yielded 160 mg (55%) of 2 as single
crystals. The data obtained from a single-crystal X-ray structure
analysis were consistent with the structural data of compound 2
reported earlier.9
Acknowledgment. This work was supported by the
Deutsche Forschungsgemeinschaft and the Fonds der Che-
mischen Industrie.
Supporting Information Available: CIF files giving X-ray
crystallographic data for the structure determinations of 1 and 3.
This material is available free of charge via the Internet at
http://pubs.acs.org.
[{CH(PPh2NSiMe3)2}2Eu] (3). Route A. To a mixture of
K{CH(PPh2NSiMe3)2} (149 mg, 0.25 mmol) and 1 (311 mg, 0.25
mmol) was added toluene (15 mL). The mixture was stirred
overnight and filtered through a glass frit. The solution was
concentrated to 5 mL, and the precipitate that formed recrystallized
from the hot solvent, yielding 200 mg (63%) of crystalline 3 as
large orange blocks.
Route B. EuI2(THF)2 (275 mg, 0.5 mmol) and
K{CH(PPh2NSiMe3)2} (597 mg, 1.0 mmol) were dissolved in THF
(15 mL) and stirred for 16 h. The solvent was removed and the
OM800989X
(19) Sheldrick, G. M. SHELXS-97: Program for Crystal Structure
Solution; University of Go¨ttingen, Go¨ttingen, Germany, 1997.
(20) Sheldrick, G. M. SHELXL-97: Program for Crystal Structure
Refinement; University of Go¨ttingen, Go¨ttingen, Germany, 1997.