Ytterbium complexes supported by β-diketiminate ligands: Cyclopentadienyl, indenyl, and aryloxide derivatives

Article abstract of DOI:10.1016/S0277-5387(03)00053-6

Reactions of β-diketiminate ytterbium dichloride, LYbCl₂(THF)₂ (L = N,N-2,6-diisopropylphenyl-2,4-pentanediimine anion), with C₅H₅Na, in 1:1 or 1:2 molar ratio in tetrahydrofuran (THF) at room temperature give the mixed-ligand ytterbium complexes (C₅H₅)(L)YbCl (1) and (C₅H₅)₂YbL (2), respectively. LYbCl₂(THF)₂ reacts with C₉H₇K or ArONa (ArO = 2,6-BU₂^t-4-MeC₆H₂O) in 1:1 molar ratio in THF to afford (C₉H₇)(L)YbCl (3) and (ArO)(L)YbCl(THF) (4) in high yield, respectively. Crystal structure analysis revealed that complex 3 is an unsolvated monomer, in which the ytterbium atom is coordinated by one indenyl ring, two nitrogen atoms of the diketiminate ligand and one chlorine atom, while complex 4 is a THF solvated monomer with the central metal five-coordinated by two nitrogen atoms, two oxygen atoms, and one chlorine atom.

Full text of DOI:10.1016/S0277-5387(03)00053-6

Polyhedron 22 (2003) 1241Á1247
/
www.elsevier.com/locate/poly
Ytterbium complexes supported by b-diketiminate ligands:
cyclopentadienyl, indenyl, and aryloxide derivatives
Yong Zhang a, Ying-Ming Yao a, Yun-Jie Luo a, Qi Shen a,b,*, Yan Cui a, Kai-Bei Yu c
a Department of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215006, People’s Republic of China
b State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences,
Shanghai 200032, People’s Republic of China
c Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, People’s Republic of China
Received 15 November 2002; accepted 29 January 2003
Abstract
Reactions of b-diketiminate ytterbium dichloride, LYbCl2(THF)2 (Lꢀ
with C5H5Na, in 1:1 or 1:2 molar ratio in tetrahydrofuran (THF) at room temperature give the mixed-ligand ytterbium complexes
(C5H5)(L)YbCl (1) and (C5H5)2YbL (2), respectively. LYbCl2(THF)2 reacts with C9H7K or ArONa (ArOꢀ
2,6-But2 -4-MeC6H2O)
/
N,N-2,6-diisopropylphenyl-2,4-pentanediimine anion),
/
in 1:1 molar ratio in THF to afford (C9H7)(L)YbCl (3) and (ArO)(L)YbCl(THF) (4) in high yield, respectively. Crystal structure
analysis revealed that complex 3 is an unsolvated monomer, in which the ytterbium atom is coordinated by one indenyl ring, two
nitrogen atoms of the diketiminate ligand and one chlorine atom, while complex 4 is a THF solvated monomer with the central
metal five-coordinated by two nitrogen atoms, two oxygen atoms, and one chlorine atom.
# 2003 Elsevier Science Ltd. All rights reserved.
Keywords: Organolanthanide complex; Ytterbium; b-Diketiminate ligand; Synthesis; Crystal structures
1. Introduction
studied [25Á
/
27]. In contrast, the utilization of guanidi-
34] for the
nates [28Á30] and b-diketiminate ligands [31Á
/
/
In recent years, nitrogen-containing bidentate chelat-
ing ligands have attracted considerable interest in
preparation of lanthanide complexes remains relatively
poorly explored.
organometallic chemistry. Amidinates [1Á
/
5], guanidi-
Recently, we became interested in studying the
synthesis and reactivity of organolanthanide complexes
supported by the b-diketiminate ligand, and found that
the bulky b-diketiminate group (DIPPh)2nacnac (L)
nates [6,7], and b-diketiminates [8Á24] are well estab-
/
lished as ancillary ligands for transition and main group
metals. These ligand systems can coordinate metal
center in different bonding modes, and their steric and
electronic properties can be readily tuned by an appro-
priate choice of starting materials used in their synthesis.
The coordination chemistry of lanthanide elements and
Group 3 metals supported by amidinates has been
(LꢀN,N-2,6-diisopropylphenyl-2,4-pentanediimine an-
/
ion) is an ideal ligand for synthesis of the mixed-ligand
lanthanide derivatives [35]. In order to further explore
the reactivity of b-diketiminate lanthanide chloride, we
have studied the reaction of LYbCl2(THF)2 with some
anionic ligands, including cyclopentadienyl, indenyl,
and aryloxide. In this paper, we report the synthesis
and characterization of these ytterbium complexes, and
the molecular structures of (C9H7)(L)YbCl (3) and
* Corresponding author. Present address: Department of Chemistry
and Chemical Engineering, Suzhou University, Suzhou 215006,
People’s Republic of China. Tel.: ꢁ
6511-2513.
E-mail address: qshen@suda.edu.cn (Q. Shen).
/
86-512-6511-2371; fax: ꢁ86-512-
/
(ArO)(L)YbCl(THF) (4) (ArOꢀ/2,6-di-tert-butyl-4-
methylphenoxo) are also described.
0277-5387/03/$ - see front matter # 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S0277-5387(03)00053-6

1242
Y. Zhang et al. / Polyhedron 22 (2003) 1241Á1247
/
2. Experimental
1072(w), 1023(m), 935(m), 851(w), 832(m), 788(s),
783(s), 755(s), 689(w).
Reactions were performed under pure argon with
exclusion of air and moisture by Schlenk techniques.
Solvents were dried and freed of oxygen by refluxing
over Na or sodium benzophenone ketyl and distilled
under argon prior to use. Anhydrous YbCl3 [36] and
LLi [8] were prepared according to the literature
methods. C5H5Na and ArONa were obtained by the
reaction of C5H6 or ArOH with sodium in THF. C9H7K
was prepared by the reaction of C9H8 with potassium in
THF.
Melting points were determined in sealed argon-filled
capillaries and are uncorrected. Metal analyses were
carried out using complexometric titration. Carbon,
hydrogen, and nitrogen analyses were performed by
direct combustion on a Carlo Erba-1110 instrument,
quoted data are the average of at least two independent
determinations. The IR spectra were recorded on a
Nicolet-550 FTIR spectrometer as KBr pellets.
2.3. (C9H7)(L)YbCl (3)
The synthesis of complex 3 was carried out as
described for complex 1, but a THF solution of
C9H7K (1.14 ml, 5.83 mmol) was used instead of the
solution of C5H5Na. The black crystals were obtained
from concentrated toluene solution at ꢂ
(3.34 g, 77.3%). m.p.: 245Á247 8C. Anal. Calc. for
C38H48ClN2Yb: C, 61.57; H, 6.53; N, 3.78; Yb, 23.34.
Found: C, 61.33; H, 6.24; N, 3.58; Yb, 23.51%. IR (KBr,
cmꢂ1): 3062(w), 2962(vs), 2928(s), 2868(s), 1622(vs),
1552(vs), 1528(vs), 1461(s), 1437(s), 1388(s), 1363(s),
1325(s), 1276(s), 1178(s), 1096(m), 1068(w), 1019(m),
933(m), 786(m), 759(s), 692(m). The crystals suitable for
X-ray crystal structures studies were obtained by
recrystallization from toluene solution at room tem-
perature for 3 days.
/
20 8C for 4 days
/
2.1. (C5H5)(L)YbCl (1)
2.4. (ArO)(L)YbCl(THF) (4)
To a slurry of anhydrous YbCl3 (1.75 g, 6.26 mmol) in
about 40 ml THF was slowly added a solution of LLi
(20.0 ml, 6.26 mmol) in toluene/hexane at room
temperature. After YbCl3 had disappeared completely,
the THF solution of C5H5Na (9.8 ml, 6.26 mmol) was
added slowly. The mixture was stirred at room tem-
perature for another 48 h, and then the precipitate was
removed from the reaction mixture by centrifugation.
THF was completely removed in vacuum and toluene
was added to extract the product. The precipitate was
removed again by centrifugation. The orange red
crystals were obtained from the concentrated toluene
The synthesis of complex 4 was carried out as
described for complex 1, but a THF solution of ArONa
(1.56 mmol) was used in place of the solution of
C5H5Na. The red crystals were obtained from toluene
solution (1.16 g, 81.2%). m.p.: 153Á156 8C (dec). Anal.
/
Calc. for C48H72ClN2O2Yb: C, 62.83; H, 7.91; N, 3.05;
Yb, 18.86. Found: C, 62.52; H, 7.92; N, 3.07; Yb,
18.72%. IR (KBr, cmꢂ1): 3061(w), 2960(vs), 2927(s),
2867(s), 1635(s), 1621(vs), 1550(vs), 1531(vs), 1463(s),
1439(s), 1396(m), 1362(s), 1325(s), 1277(s), 1225(m),
1175(s), 1152(m), 1120(w), 1073(w), 932(m), 865(m),
789(s), 759(s), 685(w), 642(w). The crystals suitable for
X-ray crystal structures studies were obtained by
solution at ꢂ
/
10 8C for 3 days (3.61 g, 83.5%). m.p.:
218Á220 8C. Anal. Calc. for C34H46ClN2Yb: C, 59.08;
/
H, 6.71; N, 4.05; Yb, 25.03. Found: C, 58.87; H, 6.67; N,
3.98; Yb, 24.87%. IR (KBr, cmꢂ1): 3058(m), 2961(vs),
2928(s), 2865(s), 1622(vs), 1551(vs), 1521(vs), 1463(s),
1435(s), 1388(s), 1365(s), 1316(s), 1265(s), 1172(m),
1101(m), 1071(w), 1022(m), 931(m), 852(w), 835(m),
788(s), 782(s), 756(s), 689(w).
recrystallization from THFÁ
for a week.
/
toluene solution at ꢂ5 8C
/
2.5. X-ray structures determination
Suitable single crystals of complexes 3 and 4 were
each sealed in thin-walled glass capillary, and intensity
data were collected at ambient temperature on a Sie-
2.2. (C5H5)2YbL (2)
The synthesis of complex 2 was carried out as
described for complex 1, but 2 equiv. of C5H5Na in
THF (17.1 ml, 10.88 mmol) was used. The orange red
crystals were obtained from the concentrated toluene
mens P4 diffractometer in v-scan mode using Mo Ka
˚
0.71073 A). Details of the intensity data
collection and crystal data are given in Table 1.
radiation (lꢀ
/
The crystal structures of these complexes were solved
by direct methods using the SHELXS-97 program and
expanded by Fourier techniques. All the non-hydrogen
atoms were refined anisotropically. Hydrogen atoms
solution at ꢂ
/
10 8C (3.42 g, 87.3%). M.p.: 235Á238 8C.
/
Anal. Calc. for C39H51N2Yb: C, 64.98; H, 7.13; N, 3.88;
Yb, 24.00. Found: C, 64.66; H, 6.98; N, 3.68; Yb,
24.25%. IR (KBr, cmꢂ1): 3056(m), 2963(vs), 2925(s),
2867(s), 1623(vs), 1551(vs), 1524(vs), 1461(s), 1433(s),
1385(s), 1366(s), 1315(s), 1264(s), 1170(m), 1103(m),
were all generated geometrically (CÃ
/
H bond lengths
˚
fixed at 0.95 A) with assigned appropriate isotropic
thermal parameters.

Y. Zhang et al. / Polyhedron 22 (2003) 1241Á
/
1247
1243
Table 1
Crystallographic data for complexes 3 and 4
gradually changed from red to black. The black crystals
obtained were identified to be (C9H7)(L)YbCl (3) by
elemental analyses, IR spectrum and X-ray crystal
structures determination (see below). Usually, the synth-
esis of unsubstituted indenyl lanthanide chlorides was
difficult due to disproportionation. To our knowledge,
there are few structurally characterized unsubstituted
indenyl lanthanide chlorides in the literature [37,38].
Complex 3 is the first example of an indenyl-containing
mixed-ligand lanthanide chloride. When LYbCl2 was
treated with 1 equiv. of ArONa in THF, the desired
mixed-ligand aryloxo ytterbium complex (ArO)(L)-
YbCl(THF) (4) was isolated as red crystals in high
yield. All reactions studied are shown in Scheme 1.
These results reveal that the (DIPPh)2nacnac anion is an
ideal ligand for the synthesis of mixed-ligand lanthanide
derivatives.
Compound
3
4
Formula
Fw
T (K)
C
38H48ClN2Yb C48H72ClN2O2Yb
917.57
290(2)
741.27
290(2)
Radiation
Crystal system
Space group
Unit cell
Mo Ka
triclinic
¯
P1
Mo Ka
triclinic
¯
P1
˚
a (A)
10.479(1)
12.392(1)
14.273(1)
97.301(7)
98.179(7)
106.933(8)
1727.0(2)
2
10.379(1)
11.193(1)
21.418(2)
84.06(1)
85.47(1)
68.86(1)
2305.9(4)
2
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
3
˚
V (A )
Z
Dcalcd (g cmꢂ3
m (Mo Ka) (cmꢂ1
F(0 0 0)
)
1.425
28.12
754
1.322
21.23
954
In the IR spectra, there are strong absorptions near
1550 and 1530 cmꢂ1, which are consistent with partial
)
Crystal size (mm)
0.58ꢃ
/
0.42
0.52ꢃ
/
0.42
CÄ
/
N double bond character [39]. These complexes are
ꢃ/0.20
ꢃ/
0.30
moderately sensitive to air and moisture, and have good
thermal stability, they are well soluble in THF and
DME, moderately in aromatic solvents, and insoluble in
aliphatic hydrocarbons, such as hexane.
2umax (8)
50.0
6625
6049
4778
50.0
8898
8117
7328
No. of reflections collected
No. of unique reflections
No of observed reflections
[I ꢀ/2.0s(I)]
GOF
R
0.949
0.0393
0.0855
1.014
0.0221
0.0548
3.2. Molecular structure of (C9H7)(L)YbCl (3)
Rw
The molecular structure of complex 3 is shown in Fig.
1, and the selected bond lengths and angles are listed in
Table 2. The coordination geometry about the ytter-
bium center approximates a three-legged piano stool
with the two nitrogen atoms of the chelating b-diketi-
minate anion, and the chlorine atom constituting the
‘‘legs’’ of the molecule, and the formal coordination
number of the central metal is 6.
Largest difference peak and
ꢂ3
2.130, ꢂ
/
0.664
0.585, ꢂ0.664
/
˚
hole (e A
)
3. Results and discussion
3.1. Synthesis
We previously reported that LYbCl2(THF)2 can be
obtained in high yield by the metathesis reaction of LLi
with YbCl3 in 1:1 molar ratio [35]. Thus, freshly
prepared LYbCl2(THF)2 in situ was used as a precursor
to synthesize the b-diketiminato ytterbium derivatives.
Anhydrous YbCl3 reacted completely with LLi in 1:1
molar ratio in THF. A THF solution of C5H5Na was
added in 1:1 or 1:2 molar ratio. After workup, orange
red crystals were obtained in high yield, which were
identified to be (C5H5)(L)YbCl (1) and (C5H5)2YbL (2)
by elemental analyses, respectively. We proposed that
complex 1 exists as a monomer according to the
structures of the analogous complex (CH3C5H4)-
(L)YbCl which was identified by structure determina-
tion [35]. Complex 2 may be a solvent-free monomer,
just like (C5H5)3Yb, one b-diketiminato instead of one
C5H5ꢂ to coordinate to the ytterbium atom. Attempts
to determine the definitive structures of 1 and 2 were
unsuccessful due to twinning of the crystals.
The YbÃ
/
C(13) and YbÃ
/
C(15) distances are 3.124(6)
and 3.120(6) A, respectively, which are somewhat longer
˚
than those corresponding bond distances of 3.086(4) and
˚
3.049(5) A in (CH3C5H4)(L)YbCl [35], but still compar-
able with those of 2.986(6) and 3.180(9) A for bridging
h2-C5H5 bonding in (C5Me5)2Sm(m-C5H5)Sm(C5Me5)2
[40], and 2.814(4)Á
Yb bonding in [Yb(Odpp)3] (Odppꢀ
˚
6
1
˚
/
3.148(6) A for chelating h -, h -Ph-
2,6-diphenylphe-
/
nolate) [41], respectively. Therefore, the b-diketiminate
ligand can be considered to coordinate to ytterbium in a
h4 fashion. The bond distances of C(13)Ã
/
C(14), C(14)Ã
/
C(15), N(1)Ã
/
C(13) and N(2)Ã
/
C(15) (see Table 2) fall in
the range of corresponding distances of single and
double bonds, which reflect substantial electron deloca-
lization within the backbone of the b-diketiminate
ligand.
The b-diketiminate ligand is symmetrically coordi-
nated to the ytterbium atom with the variation of 0.008
˚
˚
A in YbÃ
/
N bond lengths (2.245(4) and 2.237(4) A,
N bond length of
with that in
When 1 equiv. of C9H7K in THF was added to the
THF solution of LYbCl2, the color of the solution
respectively). The average YbÃ
/
˚
A
2.241(4)
is
comparable

1244
Y. Zhang et al. / Polyhedron 22 (2003) 1241Á1247
/
Scheme 1.
Fig. 1. Molecular structure of complex 3 (hydrogen atoms omitted for clarity).

Y. Zhang et al. / Polyhedron 22 (2003) 1241Á
/
1247
1245
Table 2
Table 3
˚
˚
Selected bond lengths (A) and angles (8) for complex 3
Selected bond lengths (A) and angles (8) for complex 4
Bond lengths
Bond lengths
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
/
N(1)
N(2)
Cl
2.245(4)
2.237(4)
2.469(2)
2.614(8)
2.58(1)
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
N(1)Ã
N(2)Ã
/
C(1)
3.198(5)
3.124(6)
3.361(6)
3.120(6)
3.191(6)
1.335(7)
1.327(7)
1.395(8)
1.414(8)
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
/
N(1)
N(2)
O(1)
O(2)
Cl
2.338(2)
2.340(2)
2.024(2)
2.397(2)
2.4959(8)
3.303(3)
3.592(3)
YbÃ
N(1)Ã
N(2)Ã
/
C(15)
3.306(3)
/
/
C(13)
C(14)
C(15)
C(18)
/
/C(13)
1.340(3)
1.323(3)
1.390(4)
1.403(4)
1.347(3)
/
/
/
/C(15)
/
C(30)
C(31)
C(32)
C(33)
C(38)
C(av)
/
/
C(13)Ã
C(14)Ã
O(1)Ã
/C(14)
/
/
/
/C(15)
/
2.567(8)
2.653(6)
2.678(6)
2.617(8)
/C(13)
/C(13)
/
C(30)
/
/C(15)
/C(14)
/
C(13)Ã
/C(14)
Bond angles
N(1)ÃYbÃN(2)
O(1)ÃYbÃ
O(1)ÃYbÃ
O(1)ÃYbÃ
N(1)ÃYbÃ
N(2)ÃYbÃ
/
C(14)Ã
/C(15)
/
/
80.86(7)
141.59(7)
98.73(7)
85.24(7)
90.99(7)
170.98(7)
O(1)Ã
O(2)Ã
N(1)Ã
N(2)Ã
YbÃO(1)Ã
C(13)Ã
/
YbÃ
YbÃ
YbÃ
YbÃ
/
Cl
105.09(5)
83.73(6)
112.48(6)
102.89(6)
166.7(2)
130.5(3)
Bond angles
/
/
N(1)
N(2)
O(2)
/
/Cl
N(1)Ã
N(1)Ã
N(2)Ã
N(1)Ã
N(2)Ã
/
YbÃ
YbÃ
YbÃ
YbÃ
YbÃ
/
N(2)
Cl
83.5(2)
103.5(1)
105.9(1)
67.5(2)
N(1)Ã
N(2)Ã
C(13)Ã
C(15)Ã
C(13)Ã
/
YbÃ
YbÃ
/
C(13)
21.9(2)
67.3(2)
/
/
/
/
Cl
Cl
/
/
/
/C(13)
/
/
/
/
/
/
Cl
C(15)
C(15)
/
N(1)Ã
/Yb
119.3(4)
120.0(4)
130.9(6)
/
/O(2)
/
/C(30)
/
/
/
N(2)Ã
/Yb
/
/O(2)
/
C(14)Ã
/C(15)
/
/
21.6(2)
/
C(14)ÃC(15)
/
Complex 4 is a THF-solvated monomer, the coordi-
nated THF molecule is disordered due to strong thermal
motion. The central ytterbium atom is five-coordinated
with two nitrogen atoms from the b-diketiminate ligand,
one oxygen atom from aryloxide, one oxygen atom from
THF, and one chlorine atom in a distorted trigonal
bipyramid geometry. One nitrogen atom of the b-
diketiminate ligand (N(1)), the oxygen atom of aryl-
oxide, and the chlorine atom form the equatorial
vertices (the sum of these bond angles is 359.28), another
nitrogen atom (N(2)) and the THF ligand occupy the
(CH3C5H4)(L)YbCl, but apparently shorter than that in
(CH3C5H4)(L)YbNPh2 [35]. This may be caused by the
increased steric congestion due to the coordination of a
bulky diphenylamido group in the latter. The YbÃ
/
˚
C(ring) distances range from 2.567(8) to 2.678(6) A,
˚
C(ring) distance of 2.617(8) A,
which is comparable with those in [(C9H7)2PrCl(THF)]2
and (C9H7)3La(THF) [38] when the difference in ionic
giving the average YbÃ
/
radii was considered. The N(1)Ã
/
YbÃ
/
N(2) bond angle of
83.5(2)8 is comparable with the corresponding values in
LScCl2(THF) [33] and (CH3C5H4)(L)YbCl [35].
apical positions (Ú
/
N(2)Ã
/
YbÃ
/
O(2)ꢀ170.98(7)8; see
/
Table 3). The coordination geometry of this complex
is similar to that of (ArO)2YbCl(THF)2 [42].
3.3. Molecular structure of (ArO)(L)YbCl(THF) (4)
The b-diketiminate ligand is also symmetrically co-
ordinated to the ytterbium atom (2.338(2) and 2.340(2)
˚
N distance
The structure of complex 4 is shown in Fig. 2, and
selected bond distances and angles are listed in Table 3.
A, respectively). However, the average YbÃ
/
Fig. 2. Molecular structure of complex 4 (hydrogen atoms omitted for clarity). Each disordered THF ligand is shown in two possible orientations.

1246
Y. Zhang et al. / Polyhedron 22 (2003) 1241Á1247
/
˚
of 2.339(2) A is much longer than that in complex 3
References
˚
(2.241(4) A), taking into account the difference in
[1] F.T. Edelmann, Coord. Chem. Rev. 137 (1994) 403.
[2] M.P. Coles, R.F. Jordan, J. Am. Chem. Soc. 119 (1997) 8125.
[3] C. Averbuj, M.S. Eisen, J. Am. Chem. Soc. 121 (1999) 8755.
[4] S.R. Foley, Y.L. Zhou, G.P.A. Yap, D.S. Richeson, Inorg. Chem.
39 (2000) 924.
coordination number between these two complexes.
This can be attributed to the steric congestion around
ytterbium due to the bulky substituents on the arene
ring of b-diketiminate ligand and aryloxide. The long
distances of YbÃ
/
C(13, 14, 15) indicate that there is only
[5] K.C. Jayaratne, R.J. Keaton, D.A. Henningsen, L.R. Sita, J. Am.
Chem. Soc. 122 (2000) 10490.
purely s-bonding, and the b-diketiminate ligand is
coordinated to the ytterbium atom in an h2 manner.
There is expected electron delocalization within the
[6] P.J. Bailey, S. Pace, Coord. Chem. Rev. 214 (2001) 91.
[7] A.P. Duncan, S.M. Mullins, J. Arnold, R.G. Bergman, Organo-
metallics 20 (2001) 1808.
YbNC3N six-membered ring, which is consistent with
˚
O(Ar) bond length is 2.024(2) A.
[8] J. Feldman, S.J. McLain, A. Parthasarathy, W.J. Marshall, J.C.
Calabrese, S.D. Arthur, Organometallics 16 (1997) 1514.
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(1999) 8673.
the IR results. The YbÃ
/
˚
Subtraction of the estimated ionic radius (0.81 A) for
five-coordinate Yb3ꢁ from this value gives 1.21 A,
˚
[10] B. Qian, W.J. Scanlon, IV, M.R. Smith, III, D.H. Motry,
Organometallics 18 (1999) 1693.
which is comparable with that in (ArO)YbCl2(THF)3
˚
(1.21 A) [43], but apparently shorter than that in
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(1998) 1315.
˚
(ArO)2YbCl(THF)2 (1.27 A) [42]. The YbÃ
/
Cl distance
is 2.4959(8) A. This value is comparable with those in
˚
[12] V.C. Gibson, J.A. Segal, A.J.P. White, D.J. Williams, J. Am.
Chem. Soc. 122 (2000) 7120.
˚
(ArO)2YbCl(THF)2 (2.4770(9) A) [42] and (Ar-
[13] W.K. Kim, M.J. Fevola, L.M. Liable-Sands, A.L. Rheingold,
K.H. Theopold, Organometallics 17 (1998) 4541.
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S. Collins, Organometallics 19 (2000) 2161.
O)YbCl2(THF)3 (2.555(2)) [43] when the difference in
O distance
coordination number is considered. The CÃ
/
˚
of the phenolate ligand is 1.347(3) A, which is appar-
ently shorter than the single bond length, reflecting
substantial electron delocalization from oxygen into the
aromatic rings.
[15] A.P. Dove, V.C. Gibson, E.L. Marshall, A.J.P. White, D.J.
Williams, J. Chem. Soc., Chem. Commun. (2001) 283.
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Lobkovsky, G.W. Coates, J. Am. Chem. Soc. 123 (2001) 8738.
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Lobkovsky, G.W. Coates, J. Am. Chem. Soc. 123 (2001) 3229.
[18] X. Dai, T.H. Warren, J. Chem. Soc., Chem. Commun. (2001)
1998.
The N(1)Ã
/
YbÃN(2) bond angle is 80.86(7)8, which is
/
comparable with the corresponding values in complexes
3, LScCl2(THF) [33] and (CH3C5H4)(L)YbCl [35]. The
YbÃ
/
O(1)ÃC(30) angle is 166.7(2)8, which is smaller than
/
[19] P.J. Bailey, R.A. Coxall, C.M. Dick, S. Fabre, S. Parsons,
Organometallics 20 (2001) 798.
the corresponding values in (ArO)2YbCl(THF)2
(172.5(1)8) [42], and (ArO)YbCl(THF)3 (179.7(3)8)
[43]. This may be attributed to the difference in steric
crowding around the metal among these compounds.
[20] Y. Ding, H.W. Roesky, M. Noltemeyer, H.G. Schmidt, P.P.
Power, Organometallics 20 (2001) 1190.
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1000.
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Chem. Commun. (1999) 705.
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J. Organomet. Chem. 622 (2001) 190.
4. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Center, CCDC No. 183737 for complex 3 and
183738 for complex 4. Copies of this information may
be obtained free of charge from the Director, CCDC, 12
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