Sterically demanding chelating diamide complexes of yttrium and lutetium

Article abstract of DOI:10.1021/om0204639

Deprotonation of the bridged diamine ArHN(CH₂)₃NHAr (Ar = 2,6-iPr₂C₆H₃) with n-butyllithium and potassium hydride, respectively, gives the corresponding alkali metal derivatives M₂{ArN(CH

Full text of DOI:10.1021/om0204639

4756
Organometallics 2002, 21, 4756-4761
Ster ica lly Dem a n d in g Ch ela tin g Dia m id e Com p lexes of
Yttr iu m a n d Lu tetiu m
Peter W. Roesky
Institut fu¨r Chemie, Freie Universita¨t Berlin,
Fabeckstrasse 34-36, 14195 Berlin, Germany
Received J une 13, 2002
Deprotonation of the bridged diamine ArHN(CH2)3NHAr (Ar ) 2,6-iPr2C6H3) with
n-butyllithium and potassium hydride, respectively, gives the corresponding alkali metal
derivatives M2{ArN(CH2)3NAr} (M ) Li (1a ), K (1b)). 1a reacts with yttrium trichloride to
form the metalate complex [Y{ArN(CH2)3NAr}(THF)2(µ-Cl)2Li(THF)2] (2). The coordination
number of yttrium in 2 is six. The structure of 2 shows two bridging chloride ligands and an
alkali metal bound by two solvate molecules. Further reaction of 2 with NaC5H5 in THF
affords the complex [Y{ArN(CH2)3NAr}(η5-C5H5)(THF)] (4). The structure of 4 in solution
and in the solid state is best described as a distorted tetrahedron. Reaction of 1b with
anhydrous lutetium trichloride leads to the unexpected ionic product [LuCl2(THF)5][Lu{ArN-
(CH2)3NAr}2] (5). 5 can be formally considered as a derivative of the ionic compound [LuCl2-
(THF)5][LuCl4(THF)2], in which all four chlorine atoms of the anion are substituted by 2
equiv of the {ArN(CH2)3NAr}2- ligand. As seen from all three structures, the steric demand
of the {ArN(CH2)3NAr}2- ligand is less than that of two (C5Me5)- moieties.
In tr od u ction
tunable reactivity not only via modification of the ligand
sphere but also via variation of the metal ionic radius.9
In an attempt to extend the possibility of modifying and
controlling the reactivity, recent research efforts have
been directed toward substitution of the cyclopentadi-
enyl ligands in the metallocene setup by other anionic
nitrogen-based bidentate ligand systems10 such as di-
azadienes,11 amidinates,12 diamido ligands,13 or other
combinations of nitrogen and oxygen atoms14 to increase
the electrophilicity of the metal center and to create a
different steric environment at the reactive site. Linking
various anionic functionalities such as amides and
aryloxides together by a covalent bridge has been a very
useful concept in transition-metal chemistry to deter-
mine complex geometry and limiting ligand mobility.13,15
Our attention is drawn to the sterically demanding
Metallocenes of organolanthanides1 have proven to be
highly efficient catalysts2 for a variety of olefin trans-
formations including hydrogenation,3,4 polymerization,5
hydroamination,4,6 hydrosilylation,7 and hydroboration.8
Organolanthanides combine facile ligand exchange and
high electrophilicity, while the lanthanide series offers
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(11) (a) Go¨rls, H.; Neumu¨ller, B.; Scholz, A.; Scholz, J . Angew. Chem.
1995, 107, 732-735; Angew. Chem., Int. Ed. Engl. 1995, 34, 673-676.
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2001, 20, 4394-4402.
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481. (b) Edelmann, F. T. Top. Curr. Chem. 1996, 179, 113-148. (c)
Roesky, P. W. Chem. Soc. Rev. 2000, 29, 335-345.
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2896-2905. (b) Graf, D. D.; Davis, W. M.; Schrock, R. R. Organome-
tallics 1998, 17, 5820-5814. (c) Spannenberg, A.; Arndt, P.; Kempe,
R. Angew. Chem. 1998, 110, 824-827; Angew. Chem., Int. Ed. 1998,
37, 832-835. (d) Spannenberg, A.; Oberthu¨r, M.; Noss, H.; Tillack, A.;
Arndt, P.; Kempe, R. Angew. Chem. 1998, 110, 2190-2192; Angew.
Chem., Int. Ed. 1998, 37, 2079-2082.
(14) Duchateau, R.; Tuinstra, T.; Brussee, E. A. C.; Meetsma, A.;
van Duijnen, P. T.; Teuben, J . H. Organometallics, 1997, 16, 3511-
3522.
(5) (a) Ballard, D. G. H.; Courtis, A.; Holton, J .; McMeeking, J .;
Pearce, R. J . Chem. Soc., Chem. Commun. 1978, 994-995. (b) Watson,
P. L. J . Am. Chem. Soc. 1982, 104, 337-339. (c) Bunel, E. E.; Burger,
B. J .; Bercaw, J . E. J . Am. Chem. Soc. 1988, 110, 976-981. (d)
Coughlin, E. B.; Bercaw, J . E. J . Am. Chem. Soc. 1992, 114, 7607-
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Schumann, H.; Marks, T. J . J . Am. Chem. Soc. 1985, 107, 8091-8103.
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1996, 118, 9295-9306. (d) Roesky, P. W.; Stern, C. L.; Marks, T. J .
Organometallics 1997, 16, 4705-4711. (e) Li, Y.; Marks, T. J . J . Am.
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10.1021/om0204639 CCC: $22.00 © 2002 American Chemical Society
Publication on Web 10/05/2002

Chelating Diamide Complexes of Y and Lu
Organometallics, Vol. 21, No. 22, 2002 4757
bridged diamide ligand {ArN(CH2)3NAr}2- (Ar ) 2,6-
iPr2C6H3). We are particularly interested in the steric
and electronic effects of this ancillary ligand. It is
expected, that the linked diamide ligand system, to-
gether with the linked aminopyridinato16 and ami-
notroponiminate ligands, will form an interesting set
of ancillary ligands for a new kind of lanthanide
chemistry.17 The {ArN(CH2)3NAr}2- ligand was previ-
ously introduced by McConville et al. in group 4
chemistry by reaction of ArHN(CH2)3NHAr with
[M(NMe2)4] (M ) group 4 metal). The resulting products
were further reacted to give new polymerization cata-
lysts.18
In this article the synthesis of the alkali diamides
M2{ArN(CH2)3NAr} (M ) Li, K) is reported, along with
details of further reactions of this reagent with yttrium
and lutetium chlorides. These reactions lead to a series
of lanthanide diamido complexes having the {ArN-
(CH2)3NAr}2- ligand in the coordination sphere.
THF. The mixture was warmed to room temperature and
stirred for 6 h. The reaction mixture was refluxed for 8 h and
then stirred again for 18 h at room temperature. The remain-
ing KH was filtered off and the filtrate concentrated in vacuo.
The remaining yellow residue was washed with n-pentane (3
× 50 mL) and dried in vacuo. Yield: 2.50 g (40%). 1H NMR
(THF-d8, 250 MHz, 25 °C): δ 1.19 (d, 24H, CHMe2, 3J (H,H) )
6.4 Hz), 1.95 (quint, 2H, NCH2CH2, 3J (H,H) ) 6.9 Hz), 3.00
3
(t, 4H, NCH2CH2, J (H,H) ) 6.9 Hz), 3.37 (sept, 4H, CHMe2,
3J (H,H) ) 6.9 Hz), 6.62 (d, 2H, Ph, 3J (H,H) ) 7.4 Hz), 7.01
3
(m, 4H, Ph, J (H,H) ) 7.3 Hz). 13C NMR (THF-d8, 62.5 MHz,
25 °C): δ 26.3 (CHMe2), 28.3 (NCH2CH2), 33.0 (CHMe2), 51.2
(NCH2CH2), 129.9 (Ph), 124.3 (Ph), 143.4 (Ph), 144.6 (Ph).
[Y{Ar N(CH2)3NAr }(THF )2(µ-Cl)2Li(THF )2] (2). THF (10
mL) was condensed at -196 °C onto a mixture of YCl3 (234
mg, 1.2 mmol) and 1a (406 mg, 1.0 mmol), and the mixture
was stirred for 18 h at room temperature. The solvent was
then evaporated in vacuo, and toluene (10 mL) was condensed
onto the mixture. The solution was filtered, and the solvent
was removed. The remaining solid was washed with n-pentane
(10 mL) and dried in vacuo. Finally, the product was crystal-
lized from THF/n-pentane (1:4). Yield: 520 mg (61%). 1H NMR
(THF-d8, 250 MHz, 25 °C): δ 1.19 (d, 12H, CHMe2, 3J (H,H) )
6.9 Hz), 1.26 (d, 12H, CHMe2, 3J (H,H) ) 6.8 Hz), 1.76 (m,
THF), 2.48 (br, 2H, NCH2CH2), 3.34 (t, 4H, NCH2CH2, 3J (H,H)
Exp er im en ta l Section
Gen er a l P r oced u r es. 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 diethyl ether)
were predried over Na wire 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 Aldrich Inc. (all 99 atom % D)
and were degassed, dried, and stored in vacuo over Na/K alloy
in resealable flasks. NMR spectra were recorded on Bruker
AC 250. Chemical shifts are referenced to internal solvent
resonances and are reported relative to tetramethylsilane.
ArHN(CH2)3NHAr (Ar ) 2,6-iPr2C6H3)18c was prepared ac-
cording to literature procedures.
3
) 5.3 Hz), 3.61 (m, THF), 4.18 (sept, 4H, CHMe2, J (H,H) )
6.8 Hz), 7.18 (m, 6H, Ph). 13C NMR (THF-d8, 62.5 MHz, 25
°C): δ 25.5 (CHMe2), 25.9 (CHMe2), 26.2 (NCH2CH2), 34.3
(CHMe2), 59.1 (NCH2CH2), 119.8 (Ph), 121.2 (Ph), 145.5 (Ph),
154.9 (Ph). Anal. Calcd for C43H72Cl2LiN2O4Y (847.78):
60.92; H 8.56; N 3.30. Found: C 60.22; H 8.23; N 3.19.
C
[Y{Ar N(CH2)3NAr }(η5-C5H5)(THF )] (4). THF (10 mL) was
condensed at -196 °C onto a mixture of 2 (350 mg, 0.41 mmol)
and NaC5H5 (44 mg, 0.5 mmol), and the mixture was stirred
for 18 h at room temperature. The solvent was then evaporated
in vacuo, and toluene (10 mL) was condensed onto the mixture.
The solution was filtered and the solvent was removed. The
remaining solid was washed with n-pentane (10 mL) and dried
in vacuo. Finally, the product was crystallized from toluene.
Yield: 190 mg (75%). 1H NMR (C6D6, 250 MHz, 25 °C): δ 1.23
(d, 6H, CHMe2, 3J (H,H) ) 7.0 Hz), 1.27 (m, THF), 1.29 (d, 6H,
CHMe2, 3J (H,H) ) 7.0 Hz), 1.64 (d, 6H, CHMe2, 3J (H,H) ) 6.9
Hz), 1.71 (d, 6H, CHMe2, 3J (H,H) ) 6.8 Hz), 3.24 (m, 1H,
NCH2CH2), 3.28 (m, 1H, NCH2CH2), 3.34 (sept, 2H, CHMe2,
3J (H,H) ) 6.8 Hz), 3.39 (m, 2H, NCH2CH2), 3.64 (m, THF),
3.85 (m, 2H, NCH2CH2), 4.16 (sept, 2H, CHMe2, 3J (H,H) )
6.8 Hz), 6.06 (s, 5H, C5H5), 7.16 (m, 6H, Ph). 13C NMR (THF-
d8, 62.5 MHz, 25 °C): δ 25.3 (CHMe2), 26.3 (CHMe2), 26.4
(NCH2CH2), 28.2 (CHMe2), 29.0 (CHMe2), 29.2 (CHMe2), 35.1
(CHMe2), 59.8 (NCH2CH2), 113.1 (C5H5), 123.6 (Ph), 123.8 (Ph),
125.4 (Ph), 146.5 (Ph), 144.6 (Ph), 152.4 (Ph). Anal. Calcd for
Li2{Ar N(CH2)3NAr } (1a ). A 1.6 M solution (16.3 mL, 26.0
mmol) of nBuLi in hexane was added slowly to a stirred
solution of ArHN(CH2)3NHAr (Ar ) 2,6-iPr2C6H3) (4.67 g, 11.8
mmol) in 50 mL of n-pentane at 0 °C. A white precipitate was
immediately formed. The mixture was then stirred for 16 h at
room temperature and filtered, and the remaining white
residue was dried in vacuo. Yield: 4.75 g (99%). 1H NMR (THF-
d8, 250 MHz, 25 °C): δ 1.15 (d, 24H, CHMe2, 3J (H,H) ) 6.8
3
Hz), 1.87 (br, 2H, NCH2CH2), 3.48 (sept, 4H, CHMe2, J (H,H)
3
) 6.8 Hz), 3.54 (t, 4H, NCH2CH2, J (H,H) ) 5.9 Hz), 6.15 (d,
C
36H53N2OY (618.71) C 69.88; H 8.63; N 4.53. Found: C 69.72;
2H, Ph, 3J (H,H) ) 7.4 Hz), 6.68 (d, 4H, Ph, 3J (H,H) ) 7.3 Hz).
13C NMR (THF-d8, 62.5 MHz, 25 °C): δ 25.1 (CHMe2), 28.8
(NCH2CH2), 40.4 (CHMe2), 59.3 (NCH2CH2), 113.3 (Ph), 123.1
(Ph), 140.0 (Ph), 161.2 (Ph).
H 8.41; N 4.22.
[Lu Cl2(THF )5][Lu {Ar N(CH2)3NAr }2] (5). THF (10 mL)
was condensed at -196 °C onto a mixture of LuCl3 (365 mg,
1.3 mmol) and 1b (466 mg, 1.0 mmol), and the mixture was
refluxed for 8 h. The solution was filtered, and the filtrate was
concentrated in vacuo. Onto 5 mL of the solution 20 mL of
n-pentane was layered. After 1 day colorless crystals were
K2{Ar N(CH2)3NAr } (1a ). To a suspension of KH (1.6 g, 40.0
mmol) in THF was slowly added at 0 °C ArHN(CH2)3NHAr
(Ar ) 2,6-iPr2C6H3) (5.2 g, 13.2 mmol) dissolved in 50 mL of
1
obtained. Yield: 216 mg (28%). H NMR (THF-d8, 250 MHz,
(15) (a) Bambirra, S.; Brandsma, M. J . R.; Brussee, E. A. C.;
Meetsma, A.; Hessen, B.; Teuben, J . H Organometallics 2000, 19,
3197-3204. (b) Bambirra, S.; Meetsma, A.; Hessen, B.; Teuben, J . H.
Organometallics 2001, 20, 782-785. (c) Lee, C. H.; La, Y.-H.; Park, J .
W. Organometallics 2000, 19, 344-351. (d) Ko, B.-T.; Wu, C.-C.; Lin,
C.-C. Organometallics 2000, 19, 1864-1869.
25 °C): δ 1.25 (br, 48H, CHMe2), 1.76 (m, THF), 2.40 (m, 4H,
NCH2CH2), 3.39 (m, 8H, NCH2CH2), 3.61 (m, THF), 4.15 (br,
8H, CHMe2), 6.75-7.05 (m, 12H, Ph). 13C NMR (THF-d8, 62.5
MHz, 25 °C): δ 24.7 (CHMe2), 25.9 (CHMe2), 28.4 (NCH2CH2),
33.2 (CHMe2), 51.3 (NCH2CH2), 123.3 (Ph), 124.0 (Ph), 145.7
(Ph), 146.8 (Ph). Anal. Calcd for C74H120Cl2Lu2N4O5 (1566.58):
C 56.73; H 7.72; N 3.58. Found: C 56.21; H 7.62; N 3.14.
X-r a y Cr ysta llogr a p h ic Stu d ies of 2, 4, a n d 5. Crystals
of 2 and 5 were grown from THF/n-pentane (1:4). Crystals of
4 were obtained from hot toluene. A suitable crystal was
covered in mineral oil (Aldrich) and mounted onto a glass fiber.
(16) Noss, H.; Oberthu¨r, M.; Fischer, C.; Kretschmer, W. P.; Kempe,
R. Eur. J . Inorg. Chem. 1999, 2283-2288.
(17) (a) Roesky, P. W. Inorg. Chem. 1998, 37, 4507-4511. (b) Roesky,
P. W.; Bu¨rgstein, M. R. Inorg. Chem. 1999, 38, 5629-5632.
(18) (a) Scollard, J . D.; McConville, D. H.; Payne, N. C.; Vittal J . J .
Macromolecules 1996, 29, 5241-5243. (b) Scollard, J . D.; McConville,
D. H. J . Am. Chem. Soc. 1996, 118, 10008-10009. (c) Scollard, J . D.;
McConville, D. H.; Vittal, J . J . Organometallics 1997, 16, 4415-4420.

4758 Organometallics, Vol. 21, No. 22, 2002
Roesky
Ta ble 1. Cr ysta llogr a p h ic Deta ils of [Y{Ar N(CH2)3NAr }(THF )2(µ-Cl)2Li(THF )2] (2),
[Y{Ar N(CH2)3NAr }(η5-C5H5)(THF )] (4), a n d [Lu Cl2(THF )5][Lu {Ar N(CH2)3NAr }2] (5)a
2
4
5
formula
fw
C
43H72Cl2LiN2O4Y
C36H53N2OY
618.71
C74H120Cl2Lu2N4O5
1566.58
847.78
space group
a, Å
b, Å
C2/c (No. 15)
34.75(2)
13.164(10)
20.355(10)
100.83(6)
9145(9)
Pnma (No. 62)
17.1924(12)
19.1941(13)
10.3713(7)
I2/a (No. 15)
34.5244(2)
13.2780(7)
36.1322(2)
115.30(8)
14975(15)
8
c, Å
â, deg
V, Å3
3422.5(4)
4
1.201
Ag KR (λ ) 0.56087 Å)
0.952
none
Z
8
density (g/cm3)
radiation
µ, mm-1
1.232
1.390
Mo KR (λ ) 0.71073 Å)
1.432
none
Mo KR (λ ) 0.71073 Å)
2.742
none
abs corr
no. of reflns collected
no. of unique reflns
no. of obsd reflns
no. of data; params
R1;b wR2c
17 433
5915 [Rint ) 0.0923]
4926
5722; 437
0.0697; 0.1947
21 432
4506 [Rint ) 0.0935]
3325
4506; 188
0.0570; 0.1452
23 249
10458 [Rint ) 0.0337]
9135
10 458, 693
0.0347; 0.0948
All data collected at 203 K. R1 ) ∑||Fo| - |Fc||/∑|Fo|. wR2 ) {∑[w(Fo - Fc2)2]/∑[w(Fo2)2]}1/2
.
a
b
b
2
The crystal was transferred directly to the -73 °C cold N2
stream of a Stoe IPDS diffractometer. Subsequent computa-
tions were carried out on an Intel Pentium III PC.
lithium in n-pentane (eq 1). It was obtained as a very
air-sensitive white powder and was characterized by 1H
and 13C NMR spectroscopy. 1a was previously reported
but not formally characterized.21 In comparison to the
neutral ligand, ArHN(CH2)3NHAr, the NMR signals of
1a show only a slight shift. Most significant, the NCH2
group (δ 3.54) is shifted 0.53 ppm downfield upon
metalation of the ligand. As has been observed previ-
ously for ArHN(CH2)3NHAr, the room-temperature
NMR spectrum of 1a is indicative of a symmetrical
structure in solution.18c
All structures were solved by the Patterson method
(SHELXS-9719). The remaining non-hydrogen atoms were
located from successive difference Fourier map calculations.
The refinements were carried out by using full-matrix least-
squares techniques on F, minimizing the function (Fo - Fc)2,
where the weight is defined as 4Fo2/2(Fo2) and Fo and Fc are
the observed and calculated structure factor amplitudes using
the program SHELXL-97.20 In the final cycles of each refine-
ment, all non-hydrogen atoms except C28-C43 and O1 (2),
C18-C21 (4), and C11-C12, C22-C24, C34-C36, C38-C39,
C50-C51, C53-C54, C61, C71-C74 (5) were assigned aniso-
tropic temperature factors. Carbon-bound hydrogen atom
positions were calculated and allowed to ride on the carbon 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, and bond distances and
angles have been deposited as Supporting Information. Crys-
tallographic data (excluding structure factors) for the struc-
tures reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication nos. CCDC-157635 (2), 186894 (4), and 157636 (5).
Copies of the data can be obtained free of charge on application
to CCDC, 12 Union Road, Cambridge CB21EZ, UK (fax:
(+(44)1223-336-033; email: deposit@ccdc.cam.ac.uk).
The potassium salt K2{ArN(CH2)3NAr} (1b) was
synthesized by treatment of the neutral ligand with an
excess of KH in THF (eq 1) and was characterized by
1H and 13C spectroscopy. The observed chemical shift
is in good agreement with the lithium salt 1a .
Yttr iu m Com p lexes. Transmetalation of 1a with
anhydrous yttrium trichloride in THF at room temper-
ature and crystallization from THF/n-pentane (1:4)
leads to the reaction product [Y{ArN(CH2)3NAr}(THF)2-
(µ-Cl)2Li(THF)2] (2) (eq 2). The new complex has been
characterized by standard spectroscopic techniques, and
the solid-state structure was established by single-
crystal X-ray diffraction. As observed earlier for zirco-
nium compounds such as [Zr{ArN(CH2)3NAr}Cl2] and
[Zr{ArN(CH2)3NAr}(NMe2)2], the 1H and 13C{1H} NMR
spectra of 2 show a diastereotopic splitting of the
isopropyl CH3 signals, which is interpreted as a conse-
Resu lts a n d Discu ssion
The synthesis of the alkali diamides M2{ArN(CH2)3-
NAr} (M ) Li, K; Ar ) 2,6-iPr2C6H3) is reported first,
followed by the synthesis and structural characteriza-
tion of the yttrium and lutetium complexes [Y{ArN-
(CH2)3NAr}(THF)2(µ-Cl)2Li(THF)2], [Y{ArN(CH2)3NAr}-
(η5-C5H5)(THF)], and LuCl2(THF)5][Lu{ArN(CH2)3NAr}2].
Alk a li Meta l Com p ou n d s. The lithium compound
Li2{ArN(CH2)3NAr} (1a ) was readily prepared by treat-
ment of ArHN(CH2)3NHAr with 2 equiv of n-butyl-
(19) Sheldrick, G. M. SHELXS-97, Program of Crystal Structure
Solution; University of Go¨ttingen: Germany, 1997.
(20) Sheldrick, G. M. SHELXL-97, Program of Crystal Structure
Refinement; University of Go¨ttingen: Germany, 1997.
(21) Scollard, J . D.; McConville, D. H.; Vittal, J . J .; Payne, N. C J .
Mol. Catal. A 1998, 128, 201-214.

Chelating Diamide Complexes of Y and Lu
Organometallics, Vol. 21, No. 22, 2002 4759
octahedral arrangement. Due to the 6-fold coordination
sphere around the yttrium in 2, the Cl1-Y-Cl2 angle
of the constrained bridge to lithium (78.43(6)°) is smaller
than in the metallocene [Y(C5Me5)2(µ-Cl)2Li(THF)2] (3)
(Cl1-Y-Cl2 84.8(1)°).22 On the other hand, the Y-Cl
and Li-Cl bond distances in 2 (Y-Cl1 2.788(2) Å,
Y-Cl2 2.657(2) Å; Li-Cl1 2.315(12) Å, Li-Cl2 2.311(13)
Å) and 3 (Y-Cl1 2.646(12) Å, Y-Cl2 2.655(4) Å; Li-
Cl1 2.391(15) Å, Li-Cl2 2.357(3) Å) are as expected in
a comparable range. In compound 2 the Y-N and Y-O
bond lengths are in the expected range of Y-N1 2.218(4)
pm, Y-N2 2.245(4) pm; Y-O1 2.449(4) Å, Y-O2 2.509(4)
Å (Y-N 2.236(3) Å in [Y{(iPr)2ATI}{N(SiMe3)2}2]
({(iPr)2ATI} ) N-isopropyl-2-(isopropylamino)tropon-
iminate)).23 The N1-Y-N2 (92.5(2)°), N1-Y-O1
(94.5(2)°), and N2-Y-O2 bond angles (87.6(2)°) are in
the range of 90°, whereas the N2-Y-O1 angle (100.86-
(15)°) is significantly larger.
F igu r e 1. Perspective ORTEP view of the molecular
structure of 2. Thermal ellipsoids are drawn to encompass
50% probability. Hydrogen atoms are omitted for clarity.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) of [Y{Ar N(CH2)3NAr }(THF )2(µ-Cl)2Li(THF )2]
(2)
By reaction of 2 with NaC5H5 in THF the chlorine
atom, one molecule of THF, and the LiCl unit can be
replaced by a η5-coordinated cyclopentadienyl ligand to
afford the complex [Y{ArN(CH2)3NAr}(η5-C5H5)(THF)]
(4) as crystalline solid (eq 3). Compound 4 can be
Bond Lengths (Å)
Y-N1 2.218(4)
Y-O1 2.449(4)
Y-Cl1 2.788(2)
Y-Li 3.650(12)
Li-O4 1.96(2)
Li-Cl2 2.311(13)
Y-N2 2.245(4)
Y-O2 2.509(4)
Y-Cl2 2.657(2)
Li-O3 1.936(15)
Li-Cl1 2.315(12)
Bond Angles (deg)
N1-Y-N2 92.5(2)
N1-Y-O1 94.5(2)
N1-Y-O2 172.2(2)
N1-Y-Cl2 98.00(13)
N2-Y-O1 100.86(15)
N2-Y-Cl1 165.76(12)
O1-Y-O2 77.79(15)
O1-Y-Cl1 80.35(10)
O2-Y-Cl1 78.70(11)
N1-Y-Cl1 101.61(12)
N1-Y-Li 100.8(2)
N2-Y-O2 87.6(2)
N2-Y-Cl2 97.66(13)
O1-Y-Cl2 157.13(10)
O2-Y-Cl2 89.73(12)
Cl1-Y-Cl2 78.43(6)
quence of restricted rotation about the N-Cipso bond.18c
considered to be isoelectronic to the zirconium complex
[Zr{ArN(CH2)3NAr}(η5-C5H5)Cl],18c in which the THF
molecule of 4 is formally replaced by a chlorine atom.
Due to the comparable ion radii of yttrium and zirco-
nium, this analogy is not surprising. The new complex
has been characterized by standard analytical/spectro-
1
scopic techniques. The H and 13C{1H} NMR spectra of
4 recorded in C6D6 as solvent are consistent with a
pseudo tetrahedral geometry and Cs symmetry about
yttrium. This gives rise to two isopropyl CH resonances
and four isopropyl CH3 resonances, which are consistent
with restricted rotations about the N-Cipso bond. Simi-
1
lar patterns in the H and 13C{1H} NMR were observed
earlier for [Zr{ArN(CH2)3NAr}(η5-C5H5)Cl],18c which
indicate that the THF molecule in 4 is tightly coordi-
nated to the yttrium atom. This is also supported by
The structure of 2 was confirmed by single-crystal
X-ray diffraction in the solid state (Figure 1). Data
collection parameters and selected bond lengths and
angles are given in Tables 1 and 2. At first glance
compound 2 looks like the numerous alkali metal
adducts of the metallocenes and ansa-metallocenes of
general formula [Ln(C5Me5)2(µ-Cl)2Li(ether)2] and [Ln-
{Me2Si(C5Me4)2}(µ-Cl)2Li(ether)2].1 These structures con-
tain two bridging chloride ligands and an alkali metal
bound by two solvate molecules. In contrast to these
well-known structures in compound 2 two more mol-
ecules of THF are coordinated onto the metal center,
which indicates that the steric demand of the {ArN-
(CH2)3NAr}2- ligand is lower than that of two (C5Me5)-
ligands or one Me2Si(C5Me4)2- ligand. The coordination
number of the metal center in 2 is thus increased. The
yttrium atom is surrounded by six ligands in a distorted
1
the H and 13C{1H} NMR spectra of 4 recorded in THF-
d8 as solvent. Only broad NMR signals are observed for
the isopropyl group in THF-d8, pointing to a dynamic
behavior of 4 in THF caused by a rapid exchange of the
THF molecule. The resonance of the cyclopentadienyl
ring is always observed as a sharp singlet (δ 6.06 in
C6D6).
The solid-state structure of 4 was also established by
single-crystal X-ray diffraction (Figure 2). Data collec-
tion parameters and selected bond lengths and angles
are given in Tables 1 and 3. Overall the structure of 4
is best described as a distorted tetrahedron. Due to the
(22) Evans, W. J .; Boyle, T. J .; Ziller, J . W. Inorg. Chem. 1992, 31,
1, 1120-1122.
(23) Bu¨rgstein, M. R.; Berberich, H.; Roesky, P. W. Organometallics
1998, 17, 1452-1454.

4760 Organometallics, Vol. 21, No. 22, 2002
Roesky
F igu r e 2. Perspective ORTEP view of the molecular
structure of 4. Thermal ellipsoids are drawn to encompass
50% probability. Hydrogen atoms are omitted for clarity.
F igu r e 3. Perspective ORTEP view of the molecular
structure of 5. Thermal ellipsoids are drawn to encompass
30% probability. Hydrogen atoms are omitted for clarity.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) of [Lu Cl2(THF )5][Lu {Ar N(CH2)3NAr }2] (5)
(d eg) of [Y{Ar N(CH2)3NAr }(η5-C5H5)(THF )] (4)a
Bond Lengths (Å)
Bond Lengths (Å)
N-Y 2.171(3)
C4-N 1.429(4)
O-Y 2.371(4)
Lu1-N1 2.180(5)
Lu1-N3 2.194(5)
Lu2-O1 2.339(5)
Lu2-O3 2.352(4)
Lu2-O5 2.347(4)
Lu2-Cl2 2.506(2)
Lu1-N2 2.198(5)
Lu1-N4 2.197(5)
Lu2-O2 2.349(4)
Lu2-O4 2.366(5)
Lu2-Cl1 2.502(2)
Cg-Y 2.376(1)
Bond Angles (deg)
N-Y-N′ 97.32(15)
N-Y-O 107.63(11)
N-Y-Cg 116.78(1)
C-N-Y 133.8(2)
O1-Y-Cg 109.69(1)
Bond Angles (deg)
a
Cg ring centroid.
N1-Lu1-N2 97.0(2)
N1-Lu1-N4 114.0(2)
N2-Lu1-N4 112.7(2)
O1-Lu2-Cl1 89.34(10)
O3-Lu2-Cl1 88.26(10)
O5-Lu2-Cl1 89.82(9)
O2-Lu2-Cl2 88.58(9)
O4-Lu2-Cl2 89.21(10)
Cl1-Lu2-Cl2 178.09(5)
N1-Lu1-N3 123.4(2)
N2-Lu1-N3 116.3(2)
N3-Lu1-N4 94.4(2)
O2-Lu2-Cl1 93.24(9)
O4-Lu2-Cl1 88.98(10)
O1-Lu2-Cl2 91.79(10)
O3-Lu2-Cl2 91.74(10)
O5-Lu2-Cl2 89.05(9)
n-propyl bridge between the nitrogen atoms, the N-Y-
N′ bond angle (97.32(15)°) is slightly constrained, whereas
the N-Y-Cg angle (116.78(1)°) is enlarged (Cg ring
centroid). The remaining two bond angles are in the
expected range of a tetrahedral setup (O1-Y-Cg
109.69(1)°, N-Y-O 107.63(11)°). The N-Y (2.171(3) Å)
and O-Y (2.371(4) Å) bond distances of 4 are slightly
shorter than those observed in 2. The ring centroid-Y
bond distances of 2.376(1) Å fit well into the range of
other cyclopentadienyl complexes (e.g., [Y(MeC5H4)2-
(THF){OCN(iPr)2NPh}]: Cg1-Y 2.421(1), 2.391(2) Å).24
A comparison with metallocene complexes of the lan-
thanides such as [Ln(C5Me5)2(η5-C5H5)] (Ln ) Sm, Nd),25
which crystallize without any THF in the coordination
sphere, shows again that the steric demand of the
{ArN(CH2)3NAr}2- ligand is lower than that of two
(C5Me5)- ligands.
signals are observed for the isopropyl groups, pointing
to a dynamic behavior of 5. Even, at lower temperatures,
no sharp signals were observed.
Lu tetiu m Com p lex. In contrast to the formation of
2, no clean product could be obtained by the reaction of
1a with LuCl3. Due to the slightly smaller ion radius of
lutetium (Lu: 0.861 Å; Y: 0.900 Å),26 the formation of
a lutetium complex, which is analogous to 2, might be
prevented. On the other hand, transmetalation of 1b
with anhydrous lutetium trichloride in refluxing THF
followed by crystallization from THF/n-pentane (1:4)
leads to the unexpected ionic product [LuCl2(THF)5][Lu-
{ArN(CH2)3NAr}2] (5) (eq 4). The solid-state structure
of the new complex was established by single-crystal
X-ray diffraction (Figure 3), and characterization by
standard NMR techniques has been performed. Data
collection parameters and selected bond lengths and
angles are given in Tables 1 and 4, respectively. In the
1H and 13C{1H} NMR spectra of 5 only broad NMR
5 can be formally considered as a derivative of the
ionic compound [LuCl2(THF)5][LuCl4(THF)2], in which
all four chlorine atoms of the anion are substituted by
2 equiv of the {ArN(CH2)3NAr}2- ligand. Although the
ionic compound [LuCl2(THF)5][LuCl4(THF)2] is so far
not characterized by single-crystal X-ray diffraction,
structures of [LnCl2(THF)5][LnCl4(THF)2] (Ln ) Gd, Dy,
Er, Tb) are known.27 Due to the already mentioned
lesser steric demand of the {ArN(CH2)3NAr}2- ligand
compared to (C5Me5)-, the formation of an ate-complex
is possible. The Lu1-N distances are in the expected
(24) Mao, L.; Shen, Q.; Xue, M.; Sun, J . Organometallics 1997, 16,
3711-3714.
(25) (a) Evans, W. J .; Ulibarri, T. A.J . Am. Chem. Soc. 1987, 109,
4292-4297. (b) Tanner, P. S.; Burkey, D. J .; Hanusa, T. P. Polyhedron
1995, 14, 331-333.
(26) Shannon, R. D. Acta Crystallogr. 1976, A32, 751-760.

Chelating Diamide Complexes of Y and Lu
Organometallics, Vol. 21, No. 22, 2002 4761
range of 2.180(5)-2.197(5) Å.1b The N-Lu1-N angles
are fixed by the chelating ligand. Thus, the N-Lu1-N
angles of the metallacycles are 97.0(2)° (N1-Lu1-N2)
and 94.4(2)° (N3-Lu1-N4), whereas the other N-
Lu1-N angles range from 112.7(2)° to 123.2(2)°. Sur-
prisingly, the counterion is not potassium, but a [LuCl2-
(THF)5]+, which is pentagonal bipyramidal. The two
chlorine atoms are located in the axial positions (Cl1-
Lu2-Cl2: 178.09(5)°) having Lu-Cl bond lengths of
Cl1-Lu2 2.502(2) Å and Cl2-Lu2 2.502(2) Å. The five
THF molecules are arranged in the equatorial positions
of the pentagonal bipyramid with almost rectangular
O-Lu2-Cl angles (O-Lu2-Cl: 89.34(10)-93.24(9)°)
The Lu2-O distances are in the range 2.339(5)-2.366(5)
Å. The [LuCl2(THF)5]+ cation has been described previ-
ously. It was isolated as [LnCl2(THF)5][Co(CO)4] (Ln )
Yb, Lu) from the reaction of LnCl3 with Na[Co(CO)4] in
THF.28 In [LuCl2(THF)5][Co(CO)4] the Lu-O distances
are in the range 2.353(1)-2.364(11) Å, whereas the Lu-
Cl distance is 2.520(5) Å.
Su m m a r y
In summary, it can be emphasized that the deproto-
nation of ArHN(CH2)3NHAr with 2 equiv of n-butyl-
lithium and potassium hydride, respectively, gives the
corresponding alkali metal derivatives M2{ArN(CH2)3-
NAr} (M ) Li (1a ), K (1b)). 1a reacts with yttrium
trichloride to form the metalate complex [Y{ArN(CH2)3-
NAr}(THF)2(µ-Cl)2Li(THF)2] (2), which can be further
reacted with NaC5H5 in THF to afford the complex
[Y{ArN(CH2)3NAr}(η5-C5H5)(THF)] (4). In contrast to
the corresponding metallocenes complexes, [Y(C5Me5)2-
(µ-Cl)2Li(THF)2] (3) and [Ln(C5Me5)2(η5-C5H5)], in 2 and
4 THF is coordinated onto the center metals. Thus, the
steric demand of the {ArN(CH2)3NAr}2- ligand is lesser
than that of two (C5Me5)- moieties. This is also sup-
ported by the formation of [LuCl2(THF)5][Lu{ArN(CH2)3-
NAr}2] (5). In the ionic compound 5 the anion consists
of two {ArN(CH2)3NAr}2- ligands, which coordinate onto
one lutetium atom. 5 can be formally considered as a
derivative of the ionic compound [LuCl2(THF)5][LuCl4-
(THF)2], in which all four chlorine atoms of the anion
are substituted by 2 equiv of the {ArN(CH2)3NAr}2-
ligand. The mechanistic pathway for the formation of 5
is not completely understood.
The mechanistic pathway that leads to the formation
of 5 remains unclear. Compound 5 may be formed via a
disproportionation of an [Lu{ArN(CH2)3NAr}Cl] inter-
mediate or by a reaction of 1b with [LuCl2(THF)5]-
[LuCl4(THF)2]. Using the same reaction conditions that
led to 5 in yttrium chemistry does not give clean
products.
Ack n ow led gm en t. This work was supported by the
Deutsche Forschungsgemeinschaft and the Fonds der
Chemischen Industrie. Additionally, generous support
from Prof. Dr. D. Fenske (Universita¨t Karlsruhe) is
gratefully acknowledged.
(27) (a) Sobota, P.; Utko, J .; Szafert, S. Inorg. Chem. 1994, 33, 5203-
5206. (b) Evans, W. J .; Shreeve, J . L.; Ziller, J . W.; Doedens, R. J . Inorg.
Chem. 1995, 34, 576-585. (c) Anfang, S.; Dehnicke, K.; Magull, J . Z.
Naturforsch., B 1996, 51, 531-535. (d) Anfang, S.; Karl, M.; Faza, N.;
Massa, W.; Magull, J .; Dehnicke, K. Z. Anorg. Allg. Chem. 1997, 623,
1425-1432. (e) Willey, G. R.; Meehan, P. R.; Woodman, T. J .; Drew,
M. G. B. Polyhedron 1997, 16, 623-627.
(28) (a) Beletskaya, I. P.; Voskoboinikov, A. Z.; Magomedov, G. K.
Dokl. Akad. Nauk SSSR 1989, 306, 108-112. (b) Beletskaya, I. P.;
Voskoboynikov, A. Z.; Chuklanova, E. B.; Gusev, A. I.; Magomedov,
G. K. Metalloorg. Khim. 1988, 1, 1383-1390.
Su p p or tin g In for m a tion Ava ila ble: X-ray crystallo-
graphic files in CIF format for the structure determinations
of 2, 4, and 5 are available free of charge via the Internet at
http://pubs.acs.org.
OM0204639