Dinuclear chlorido-, alkyl(chlorido)-, and hydridoyttrium complexes supported by μ-bridging-silyl-linked bis(amidinate) ligands

Article abstract of DOI:10.1002/ejic.200901161

A chloridoyttrium complex supported by a silyl-linked bis(amidinate) ligand, [(Me₂Si{NC(Ph)N(2,6-iPr₂-C₆H ₃)}₂)₂(YCl)₂(μ-Cl)] ^-[Li(thf)₄⁺ (2) (thf = tetrahydrofuran), was synthesized by the reaction of equimolar amounts of anhydrous YCl₃ and lithium amidinate [(Me₂Si{NC(Ph)N(2,6-iPr₂C ₆H₃)}₂)₂Li₃] ^-[Li(thf)₄]⁺ (1) in thf at 20 °C. Complex 2 was isolated after recrystallization from a thf/hexane mixture in 72% yield. Single-crystal X-ray structure analysis has revealed that 2 is a dinuclear compound composed of a discrete complex anion [(Me₂Si{NC(Ph)N(2,6- iPr₂-C₆H₃)}₂)₂(YCl) ₂(μCl)^-, containing one μ-bridging and two terminal chloride ligands, and a cation [Li(thf)₄]⁺. The formation of a dimeric structure results from the coordination of amidinate fragments of the same dianionic ligand on two different yttrium ions and the presence of a μ-bridging chloride ligand. Alkylation of 2 with one equivalent of Me ₃SiCH₂Li in toluene afforded an alkyl(chlorido)yttrium complex, [Me₂Si{NC(Ph)N(2,6-iPr₂-C₆H ₃)}₂]₂[Y(thf)](μ-Cl)[Y(CH ₂SiMe₃)] (3). X-ray crystal structure investigation has shown that 3 is a dimeric complex as a result of the spanning coordination mode of the ansa-bis(amidinate) ligands and the presence of one μ²chloride ligand, while the alkyl group remains terminal. Treatment: of the in situ generated alkyl derivative [Me₂Si[NC(Ph) N(2,6-iPr₂-C₆H₃)}₂] ₂[Y(CH₂SiMe₃)]₂ (4) with PhSiH ₃ in toluene results in the formation of the corresponding hydridoyttrium complex [Me₂Si{NC(Ph)N(2,6-iPr₂C ₆H₃)}₂Y(μ-H)]₂ (5), which was isolated after recrystallization from toluene in 73% yield. According to the X-ray crystal structure analysis, 5 adopts a dimeric structure with, two μbridging bis(amidinate) and two μ²-hydrido ligands.

Full text of DOI:10.1002/ejic.200901161

FULL PAPER
DOI: 10.1002/ejic.200901161
Dinuclear Chlorido-, Alkyl(chlorido)-, and Hydridoyttrium Complexes
Supported by µ-Bridging-Silyl-Linked Bis(amidinate) Ligands
Grigorii G. Skvortsov,[a] Alexei O. Tolpyguin,[a] Georgy K. Fukin,[a] Anton V. Cherkasov,[a]
and Alexander A. Trifonov*[a]
Keywords: Rare earths / N ligands / Alkyl complexes / Hydrido complexes / Structure elucidation
A chloridoyttrium complex supported by a silyl-linked bis-
(amidinate) ligand, [(Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2)2-
(YCl)2(µ-Cl)]–[Li(thf)4]+ (2) (thf = tetrahydrofuran), was syn-
thesized by the reaction of equimolar amounts of anhydrous
YCl3 and lithium amidinate [(Me2Si{NC(Ph)N(2,6-iPr2–
C6H3)}2)2Li3]–[Li(thf)4]+ (1) in thf at 20 °C. Complex 2 was iso-
lated after recrystallization from a thf/hexane mixture in
72% yield. Single-crystal X-ray structure analysis has re-
vealed that 2 is a dinuclear compound composed of a discrete
complex anion [(Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2)2(YCl)2(µ-
Cl)]–, containing one µ-bridging and two terminal chloride
ligands, and a cation [Li(thf)4]+. The formation of a dimeric
ylation of 2 with one equivalent of Me3SiCH2Li in toluene
afforded an alkyl(chlorido)yttrium complex, [Me2Si{NC(Ph)-
N(2,6-iPr2–C6H3)}2]2[Y(thf)](µ-Cl)[Y(CH2SiMe3)] (3). X-ray
crystal structure investigation has shown that 3 is a dimeric
complex as a result of the “spanning” coordination mode of
the ansa-bis(amidinate) ligands and the presence of one µ2-
chloride ligand, while the alkyl group remains terminal.
Treatment of the in situ generated alkyl derivative
[Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2]2[Y(CH2SiMe3)]2 (4) with
PhSiH3 in toluene results in the formation of the correspond-
ing hydridoyttrium complex [Me2Si{NC(Ph)N(2,6-iPr2–
C6H3)}2Y(µ-H)]2 (5), which was isolated after recrystallization
structure results from the coordination of amidinate frag- from toluene in 73% yield. According to the X-ray crystal
ments of the same dianionic ligand on two different yttrium
ions and the presence of a µ-bridging chloride ligand. Alk-
structure analysis, 5 adopts a dimeric structure with two µ-
bridging bis(amidinate) and two µ2-hydrido ligands.
Monoanionic chelating amidinate ligands have been
widely employed in transition metal coordination and orga-
nometallic chemistry[7] and were found to form a suitable
coordination environment for isolable hydrocarbyl, hydrido,
and cationic alkyl rare earth species.[8] Tridentate amidinate
ligands containing an additional donor group in the side
chain allowed synthesis of mono- and bis(alkyl)yttrium
complexes (both neutral and ionic).[9] Lanthanide hydrido
and cationic alkyl species supported by amidinate ligands
have proved to be efficient catalysts for various olefin (poly-
merization,[8f,8g] hydroamination,[10] hydrosilylation,[11] hy-
droboration[12]) and diene (polymerization)[13] transforma-
tions. As demonstrated by the example of metallocene-type
lanthanide complexes, a transposition from a bis(cyclopen-
tadienyl) to a linked bis(cyclopentadienyl) ligation system
results in a considerable opening of the metal coordination
sphere[2a,2e,14] and effects large increases in rates of olefin
insertion into the M–R bond[2a,2e] and of olefin hydrogena-
tion.[14] To date, several linked bis(amidinate) ligand frame-
works have been described,[15] and some of them have been
successfully employed in the synthesis of lanthanide com-
plexes.[16] In order to synthesize new highly reactive rare
earth alkyl and hydrido complexes possessing enhanced
catalytic activity in olefin polymerization, we focused on
silyl-linked bis(amidinate) ligands. Herein we report the
synthesis, structure and reactivity of new dimeric chlo-
Introduction
A unique combination of properties, exceptional reactiv-
ity, and promising catalytic activity have given a strong im-
petus to the development of the organometallic chemistry
of the rare earth metals in the past two decades.[1] Rare
earth alkyl and hydrido complexes mediate a wide range of
catalytic transformations of unsaturated substrates,[2] and
their enhanced reactivity enables stoichiometric reactions of
hydrocarbon activation,[3] alkane functionalization,[4] and
C–F bond activation.[5] Both stability and reactivity of rare
earth hydrocarbyl and hydrido complexes are largely deter-
mined by coordination and steric saturation of the electro-
philic metal center, and this emphasizes the importance of
the design of new ancillary ligand sets. A fine balance be-
tween ligand electronic and steric factors needs to be main-
tained in order to control reactivity of lanthanide com-
plexes. Until recently, growing attention has been paid to
non-cyclopentadienyl ligand frameworks, because they offer
a greater variety of ligand topologies and their steric and
electronic properties may be readily modified within a wide
range.[6]
[a] G. A. Razuvaev Institute of Organometallic Chemistry of Rus-
sian Academy of Sciences
Tropinina 49, 603950 Nizhny Novgorod, GSP-445, Russia
Fax: +7-831-462-7497
E-mail: trif@iomc.ras.ru
Eur. J. Inorg. Chem. 2010, 1655–1662
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1655

A. A. Trifonov et al.
FULL PAPER
rido-, alkyl(chlorido)-, and hydridoyttrium complexes sup- the third ligand bound to the lanthanide atom.[16,18] Com-
ported by µ-bridging-silyl-linked bis(amidinate) ligands.
plex 2 contains three chloride ligands: two of them are ter-
minal, while the third is µ-bridging between two yttrium
atoms and thus participates in the formation of the dinu-
clear structure. The terminal Y–Cl bonds [2.5855(7) and
2.5803(6) Å] are predictably shorter than the bridging ones
[2.7037(6) and 2.6961(7) Å], and the lengths of both types
of bond are in good agreement with the corresponding val-
ues previously reported for yttrium metallocene com-
plexes.[19] The Y–N bonds in complex 2 are in the region of
2.3539(18)–2.3960(16) Å [the average bond length is
2.371(2) Å] and are slightly longer than the related dis-
tances in monomeric yttrium amidinate complexes.[8,16] The
N–C bond lengths within the amidinate ligands have very
similar values, which indicates negative charge delocaliza-
tion in the NCN fragments.
Results and Discussion
The metathesis reaction of anhydrous yttrium chloride
(YCl3) with lithium amidinate [(Me2Si{NC(Ph)N(2,6-iPr2–
C6H3)}2)2Li3]–[Li(thf)4]+ (1)[15b] in a 2:1 molar ratio in thf
(20 °C, 14 h) afforded the bis(amidinato)chlorido complex
[(Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2)2(YCl)2(µ-Cl)]–[Li-
(thf)4]+ (2) in 72% yield (Scheme 1). Complex 2 was isolated
as colorless air- and moisture-sensitive crystals and was au-
thenticated by elemental analysis, solution NMR studies,
and single-crystal X-ray diffraction studies. Complex 2 is
highly soluble in thf, 1,2-dimethoxyethane, and toluene, but
insoluble in hexane.
1
The H and 13C NMR spectra of complex 2 in C5D5N
at 25 °C show the expected sets of resonances due to the
amidinate ligand and the coordinated thf molecules. The
7
presence of lithium in complex 2 was confirmed by its Li
NMR spectrum, which contains a single resonance at δ =
3.3 ppm.
Colorless transparent crystals of complex 2 suitable for
single-crystal X-ray diffraction studies were grown by slow
condensation of hexane into a concentrated thf solution at
room temperature. Complex 2 was isolated as the hexane
solvate
[{(Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2)2(YCl)2(µ-
Cl)}–{Li(thf)4}+]·(C6H14)0.5
.
The molecular structure of 2 is depicted in Figure 1, and
the crystal and structural refinement data are listed in
Table 1. Surprisingly the X-ray crystal structure investiga-
tion revealed that complex 2 adopts a dimeric structure as
Figure 1. ORTEP diagram (30% probability thermal ellipsoids) of
a result of a “spanning” ligation pattern: each of the two 2 showing the atom numbering scheme. Hydrogen atoms and the
[Li(thf)4]+ cation are omitted for clarity. Selected bond lengths [Å]
dianionic amidinate ligands is µ-coordinated to two dif-
and angles [°]: Y(1)–N(2) 2.3539(18), Y(1)–N(3) 2.3573(16), Y(1)–
ferent yttrium atoms (Figure 1). Such µ-bridging coordina-
N(1) 2.3667(18), Y(1)–N(4) 2.3719(19), Y(1)–Cl(1) 2.5855(7), Y(1)–
Cl(3) 2.7037(6), Y(2)–N(8) 2.3628(19), Y(2)–N(7) 2.369(2), Y(2)–
tion of potentially chelating ligands is seldom observed and
was formerly described for a few lanthanide complexes con-
taining single-atom-linked ansa-bis(cyclopentadienyl) li-
gands.[17] It is noteworthy that linked bis(amidinate) ligands
featuring a longer (CH2)3 linker between functional groups
can display dual coordination behavior and act as both che-
N(6) 2.389(2), Y(2)–N(5) 2.3960(16), Y(2)–Cl(2) 2.5803(6), Y(2)–
Cl(3) 2.6961(7), N(1)–C(1) 1.341(2), N(2)–C(1) 1.340(3), N(3)–
C(20) 1.344(3), N(4)–C(20) 1.329(3), N(7)–C(60) 1.334(3), N(8)–
C(60) 1.340(3), N(5)–C(41) 1.326(3), N(6)–C(41) 1.334(3), N(2)–
Y(1)–N(1) 57.39(6), N(3)–Y(1)–N(4) 57.56(7), N(8)–Y(2)–N(7)
57.24(7), Y(2)–Cl(3)–Y(1) 111.59(2), N(4)–Si(1)–N(5) 108.65(9),
lating and µ-bridging ligands, depending on the nature of N(1)–Si(2)–N(8) 105.69(9).
Scheme 1.
1656
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 1655–1662

Dinuclear Yttrium Complexes with Silyl-Linked Bis(amidinate) Ligands
Table 1. Crystallographic data and structure refinement details for 2, 3 and 5.
Compound
2
3
5
Empirical formula
Formula weight
C99H139Cl3LiN8O4Si2Y2
1852.47
C101H141ClN8OSi3Y2
1780.76
C80H102N8Si2Y2
1409.70
T [K]
Wavelength [Å]
100(2)
0.71073
100(2)
0.71073
100(2)
0.71073
Crystal system
Space group
triclinic
P1
triclinic
P1
monoclinic
P21/n
¯
¯
a [Å]
b [Å]
c [Å]
α [°]
14.5217(5)
17.5020(6)
23.6035(11)
111.6460(10)
90.4680(10)
113.9820(10)
5005.6(3)
14.7966(10)
16.9858(12)
20.1565(14)
88.1090(10)
86.6220(10)
68.9250(10)
4718.5(6)
14.0342(10)
11.2920(8)
24.0172(16)
90
90.448(2)
90
3806.0(5)
2
1.230
β [°]
γ [°]
Volume [Å3]
Z
2
2
ρcalcd. [gcm–3]
1.229
1.309
1962
1.253
1.341
1896
Absorption coefficient [mm–1]
F(000)
1.595
1488
Crystal size [mm]
θ range for data collection [°]
Index ranges
0.29ϫ 0.27ϫ 0.18
2.23 to 26.00
–17 Յ h Յ 17;
21 Յ k Յ 21;
–29 Յ l Յ 29
42982
0.15ϫ 0.12ϫ 0.07
1.75 to 26.00
–18 Յ h Յ 18;
20 Յ k Յ 20;
–24 Յ l Յ 24
40553
0.29ϫ 0.24ϫ 0.07
2.46 to 26.00
–17 Յ h Յ 17;
13 Յ k Յ 13;
–29 Յ l Յ 29
31870
Reflections collected
Independent reflections
Rint
19470
0.0477
18382
0.0691
7460
0.1352
Completeness to θ [%]
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [IϾ2σ(I)]
R indices (all data)
98.9
19470/156/1219
1.040
R1 = 0.0584, wR2 = 0.1275
R1 = 0.1083, wR2 = 0.1409
1.040/–0.791
99.2
18382/5/1009
1.006
R1 = 0.0784, wR2 = 0.2029
R1 = 0.1219, wR2 = 0.2228
1.773/–3.664
99.7
7460/6/446
1.002
R1 = 0.0556, wR2 = 0.0934
R1 = 0.1289, wR2 = 0.1039
0.652/–0.657
Largest diff. peak and hole [eÅ–3]
Attempts to alkylate complex 2 with Me3SiCH2Li (tolu-
The second chlorine atom proved to be more difficult to
ene, 0 and 20 °C) at various molar ratios of reagents were substitute. The reaction of 2 with a twofold molar excess of
undertaken and revealed noticeable differences in reactivity Me3SiCH2Li in toluene with stirring at 20 °C for 3 h re-
of the chlorine atoms in the substitution reaction. One chlo- sulted in the formation of alkyl(chlorido) complex 3, which
rine atom was easily substituted by an alkyl fragment when was isolated after recrystallization from toluene at –20 °C
the reaction with an equimolar amount of Me3SiCH2Li was in 27% yield. Alkylation of 2 with an equimolar amount
carried out in toluene at 20 °C; even with a short reaction of Me3SiCH2Li can also be conducted in hexane at room
time (1 h) was enough in this case (Scheme 2). Filtration of temperature and allows isolation of 3 in 43% yield. Com-
the reaction mixture and subsequent recrystallization of the plex 3 was isolated as a highly air- and moisture-sensitive
solid residue from a toluene/hexane mixture at –20 °C af- colorless crystalline solid. It is highly soluble in thf and tol-
forded the alkyl(chlorido) complex [Me2Si{NC(Ph)N(2,6- uene and shows modest solubility in hexane. The methylene
iPr2–C6H3)}2]2[Y(thf)](µ-Cl)[Y(CH2SiMe3)] (3) in 61% protons of the alkyl group attached to the yttrium atom
1
yield.
appear in the H NMR spectrum of complex 3 (400 MHz,
Scheme 2.
Eur. J. Inorg. Chem. 2010, 1655–1662
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1657

A. A. Trifonov et al.
FULL PAPER
C6D6, 25 °C) as two doublets of doublets at δ = –0.12 and
The X-ray diffraction study revealed that complex 3 has
2
2
–0.03 ppm [dd, JH,H= 11.2 Hz, JY,H = 3.2 Hz] . This is a dimeric structure analogous to the parent complex 2,
indicative of two diastereotopic CH2 protons obviously re- which results from the coordination of the amidinate frag-
sulting from the chirality of complex 3. In the 13C NMR ments of one dianionic ligand on two different yttrium cat-
spectrum, the corresponding carbon atom gives rise to a ions. Existence of the dimeric structure is also supported by
doublet at δ = 34.9 ppm (1JY,C = 38.5 Hz). Unlike complex the presence of the µ-bridging chloride ligand, while the
2, all the methyl groups of the isopropyl substituents are alkyl group remains terminal. To the best of our knowledge,
1
nonequivalent and give rise to sixteen doublets in the H complex 3 is a rare example of a dimeric alkyl(chlorido)
NMR spectrum. Complex 3 proved to be quite a robust rare earth metal compound that includes terminal alkyl
compound: 1H NMR monitoring in a C6D6 solution at am- groups and a µ2-chlorine bridge.[20] The coordination envi-
bient temperature (25 °C) showed that decomposition of ronments of the yttrium atoms in complex 3 are different;
the complex did not exceed 10% over one month.
each contains four nitrogen atoms of two amidinate frag-
Clear transparent crystals of 3 suitable for single-crystal ments; however, the coordination sphere of one yttrium
X-ray structure investigation were obtained by slow cooling atom also includes a σ-bonded alkyl group and a µ2-bridg-
of a concentrated toluene/hexane (1:10) solution to 0 °C. ing Cl ligand, while the second yttrium atom is coordinated
Complex 3 crystallizes as a solvate containing one molecule by a thf molecule in addition to the chloride anion. Since
of toluene and one molecule of hexane. The molecular none of the yttrium atoms in the parent chlorido complex
structure of 3 is shown in Figure 2, and the crystal and 2 is coordinated by a thf molecule and the alkylation was
structural refinement data are listed in Table 1.
carried out in toluene, one can conclude that [Li(thf)4]+ is
the sole source of the thf molecule coordinated to Y in 3.
The average length of the Y–N bonds in 3 (2.375 Å) is close
to that observed in 2 (2.371 Å) and is slightly longer than
the related distances in previously reported monomeric yt-
trium amidinate complexes.[8,16] The bond lengths within
the Y(1)–Cl(1)–Y(2) moiety [Y(1)–Cl(1) 2.7714(8), Y(2)–
Cl(1) 2.6586(9) Å] in 3 are similar to those observed in a
related dimeric metallocene-type complex, Cp*2Y(µ-Cl)
YClCp*2 [2.776(5) and 2.640(5) Å],[19b] while the Y(2)–
Cl(1)–Y(1) bond angle [111.64(3)°] is remarkably larger
than that in Cp*2Y(µ-Cl)YClCp*2 [93.4(2)°].[19b] The Y–C
bond in 3 [2.404(3) Å] is slightly shorter than those in Y–
CH2SiMe3 derivatives (2.414–2.425 Å).[21]
In order to achieve replacement of both chlorine atoms
by alkyl groups and to obtain complex [Me2Si{NC(Ph)-
N(2,6-iPr2–C6H3)}2]2[Y(CH2SiMe3)]2 (4), numerous essays
of alkylation of 2 with Me3SiCH2Li were undertaken
(Scheme 3). As mentioned above, substitution of both chlo-
ride ligands in 2 is difficult to accomplish. Moreover, alkyl
derivatives of rare earth metals are known to be rather ther-
Figure 2. ORTEP diagram (30% probability thermal ellipsoids) of
3 showing the atom numbering scheme. Hydrogen atoms and CH2
groups of thf are omitted for clarity. Selected bond lengths [Å] and
angles [°]: Y(1)–N(1) 2.361(3), Y(1)–N(3) 2.383(3), Y(1)–N(2)
2.400(2), Y(1)–C(81) 2.404(3), Y(1)–N(4) 2.434(2), Y(1)–Cl(1)
2.7714(8), Y(2)–N(5) 2.314(3), Y(2)–N(8) 2.338(2), Y(2)–O(1S) mally unstable, which restricts reaction time and conditions.
2.358(2), Y(2)–N(6) 2.385(2), Y(2)–N(7) 2.400(3), Y(2)–Cl(1)
Therefore, reactions of 2 with Me3SiCH2Li (1:2 molar ratio)
2.6586(9), N(1)–Y(1)–N(2) 57.26(9), N(3)–Y(1)–N(4) 56.30(9),
were carried out in toluene (or hexane) at 0 °C over 24 h.
N(5)–Y(2)–N(6) 57.89(9), Y(2)–Cl(1)–Y(1) 111.64(3), N(1)–Si(2)–
Filtration of the reaction mixture and removal of the sol-
N(8) 106.86(13), N(4)–Si(1)–N(5) 108.51(13).
Scheme 3.
1658
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 1655–1662

Dinuclear Yttrium Complexes with Silyl-Linked Bis(amidinate) Ligands
Scheme 4.
vent afforded an off-white amorphous solid. Unfortunately
all of our attempts to obtain crystalline samples of [Me2Si-
{NC(Ph)N(2,6-iPr2–C6H3)}2]2[Y(CH2SiMe3)]2 (4) and to
isolate the alkyl species in analytically pure form failed.
Our challenge was to synthesize a new hydrido complex
supported by a linked bis(amidinate) ligation system and to
investigate its catalytic behavior in olefin polymerization.
The most common synthetic route to rare earth hydrido
complexes is the reaction of the parent alkyl derivatives
with either dihydrogen[2c,2f] or phenylsilane.[22] Because of
the difficulties of isolating alkyl complex 4, it was generated
in situ and used in the synthesis of the related hydrido de-
rivatives as a toluene (or hexane) solution after the separa-
tion of LiCl. The σ-bond metathesis reaction of 4 with two
equivalents of PhSiH3 was carried out in toluene at room
temperature over 1 h (Scheme 4). Slow cooling of the con-
centrated toluene solution to –20 °C afforded the hydride
complex [Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2Y(µ-H)]2 (5) as
a colorless crystalline solid in 73% yield.
Figure 3. ORTEP diagram (30% probability thermal ellipsoids) of
5 showing the atom numbering scheme. Hydrogen atoms [except
H(1) and H(1A)] are omitted for clarity. Selected bond lengths [Å]
and angles [°]: Y(1)–N(3) 2.324(2), Y(1)–N(2) 2.325(2), Y(1)–N(1)
2.371(2), Y(1)–N(4) 2.381(2), Y(1)–H(1) 2.55(2), Y(1)–Y(1A)
3.4661(5), N(3)–C(20) 1.352(3), N(4)–C(20) 1.327(3), N(1)–C(1)
1.319(3), N(2)–C(1) 1.345(3), N(2)–Y(1)–N(1) 57.44(6), N(3)–
Y(1)–N(4) 57.62(7), Y(1)–H(1)–Y(1A) 83.9(2), H(1)–Y(1)–H(1A)
96.1(2).
Complex 5 was isolated as a highly air- and moisture-
sensitive colorless crystalline solid. After crystallization, it
becomes insoluble in common organic solvents. Treatment
of 5 with thf or pyridine results in a chemical reaction and
gas evolution. An NMR spectrum of 5 could not be ob-
tained, because of the low solubility of 5 in organic sol-
vents. Clear colorless crystals of 5 suitable for a single-crys- bonds [2.55(2) Å] are the longest, while the Y–Y distance
tal X-ray diffraction study were obtained by slow cooling of [3.4661(5) Å] is the shortest among the known dimeric hyd-
the concentrated toluene solution to –20 °C. The molecular ridoyttrium complexes. For comparison, see: [{Me2Si(2-
structure of 5 is shown in Figure 3, and the crystal and Me–C9H5)2Y}(thf)(µ-H)]2 [2.09(3), 2.13(3); 3.6524(3) Å],[17c]
structural refinement data are listed in Table 1. X-ray analy- [(C5Me4)Me2Si(NCMe3)Y(thf)(µ-H)]2
[1.98(4)–2.48(4);
sis revealed that complex 5 does not contain Lewis bases 3.627(1) Å],[23]
[{PhC(NSiMe3)2}2Y(µ-H)]2
[2.11(3)–
and, as 2 and 3, adopts a dimeric structure as a result of 2.19(3) Å],[8a] [(MeC5H4)2Y(thf)(µ-H)]2 [3.66(1); 2.17(8),
the “spanning” coordination mode of the bis(amidinate) li- 2.19(8) Å],[24]
[(1,3-Me2–C5H3)2Y(thf)(µ-H)]2
[2.03(7),
gands. However, in this case two µ2-bridging hydride li- 2.27(6); 3.68(1) Å],[25] [(2,4,7-Me3–C9H4)2Y(µ-H)]2 [2.09(4)–
gands are also present in the coordination spheres of the 2.14(7) Å].[26] Angle Y(1)–H(1)–Y(1A) is much smaller than
yttrium atoms.
analogous angles in other dimeric hydridoyttrium com-
Despite the fact that the presence of small ligands such as plexes; for comparison, see: [Ln{(Me3Si)2NC(NiPr)2}2(µ-
hydrido or chlorido in the metal coordination sphere favors H)]2 [104.6(2)°],[27] [Y(η5:η1-C5Me4–CH2SiMe2NCMe3)-
“spanning” coordination of ansa-bis(cyclopentadienyl) li- (thf)(µ-H)]2 [122.5(2)°],[28] [Ln{(Me3Si)2NC(NcHex)2}2(µ-
gands, to date just a couple of hydrido rare earth complexes H)]2 [120.1(2)°].[29] The average Y–N bond length in 5
having “flyover dimer” structures have been report- [2.35(5) Å] is slightly shorter than those in the related com-
ed.[17a,17c] The planar tetranuclear Y2H2 core in 5 is sym- plexes 2 and 3, and this shortening obviously results from
metric and features unique geometric parameters: the Y–H the small size of the hydrido ligand.
Eur. J. Inorg. Chem. 2010, 1655–1662
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1659

A. A. Trifonov et al.
FULL PAPER
(1) (1.56 g, 1.01 mmol) in thf (30 mL) was added to a suspension
of YCl3 (0.40 g, 2.05 mmol) in thf (5 mL) at 20 °C, and the reaction
mixture was stirred at room temperature for 14 h. The reaction
mixture was filtered, and the solvent was removed in vacuo. The
remaining solid was extracted into toluene (50 mL). After filtration
of the toluene extract the solvent was removed in vacuo at room
temperature. Slow condensation of hexane into a concentrated thf
solution afforded colorless crystals of 2. The crystals were washed
with cold hexane and dried at ambient temperature in vacuo for
1 h. Yield 1.32 g (72%). C96H132Cl3LiN8O4Si2Y2 (1809.41): calcd.
C 63.72, H 7.35, N 6.19, Y 9.83; found C 63.98, H 7.61, N 6.08,
Complexes 3 and 5 and systems 2-MAO and 3-MAO
(toluene, 20 °C, 0.5 bar, [complex]/[MAO] = 1:250) showed
no activity in ethylene polymerization. Complex 5 was
found to be inert in styrene polymerization (toluene, 20 °C).
Conclusions
Here we have summarized our attempts to employ the
dianionic SiMe2-linked bis(amidinate) ligand system for the
synthesis of new chlorido-, alkyl(chlorido)-, and hydrido-
yttrium complexes. Similar to those with single-atom-linked
ansa-bis(cyclopentadienyl) ligands, yttrium complexes con-
taining the bis(amidinate) analogue [Me2Si{NC(Ph)N-
(2,6-iPr2–C6H3)}2]2– adopt dimeric structures resulting
from a “spanning” ligation pattern. Chlorido complex 2
consists of a discrete dinuclear complex anion [(Me2Si-
{NC(Ph)N(2,6-iPr2–C6H3)}2)2(YCl)2(µ-Cl)]–, which con-
tains one µ-bridging and two terminal chloride ligands, and
a cation [Li(thf)4]+. The terminal chloride ligand was easily
substituted by an alkyl group when 2 was treated with an
equimolar amount of Me3SiCH2Li to afford a dinu-
clear alkyl(chlorido) complex [Me2Si{NC(Ph)N(2,6-iPr2–
C6H3)}2]2[Y(thf)](µ-Cl)[Y(CH2SiMe3)] (3). Treatment of the
in situ generated alkyl derivative [Me2Si{NC(Ph)N(2,6-
iPr2–C6H3)}2]2[Y(CH2SiMe3)]2 (4) with PhSiH3 in toluene
allowed the formation of the dimeric hydridoyttrium com-
plex [Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2Y(µ-H)]2 (5) con-
taining two µ2-hydrido ligands. Further studies on the syn-
thesis of alkoxido- and amidolanthanide species supported
by a linked bis(amidinate) ligand system and investigation
of their catalytic activity in ring opening polymerization of
cyclic esters are currently in progress.
1
3
Y 9.80. H NMR (400 MHz, C5D5N, 25 °C): δ = 1.01 [d, JH,H
=
6.8 Hz, 12 H, CH(CH3)2], 1.06 [s, 8 H, Si(CH3)2], 1.15 [m, 12 H,
3
CH(CH3)2 and 4 H, Si(CH3)2], 1.23 [d, JH,H = 6.8 Hz, 12 H,
3
CH(CH3)2], 1.27 [d, JH,H = 6.8 Hz, 12 H, CH(CH3)2], 1.60 (s, 16
3
H, β-CH2, thf), 3.38 [sept, JH,H = 6.8 Hz, 8 H, CH(CH3)2], 3.64
(s, 16 H, α-CH2, thf), 7.06–7.56 (m, together 32 H, Ar). 13C NMR
(100 MHz, C5D5N, 25 °C): δ = –0.1 [Si(CH3)2], 22.7, 23.6, 23.9,
24.9 [CH(CH3)2], 25.8 (β-CH2, thf), 28.5, 28.7 [CH(CH3)2], 67.8 (α-
CH2, thf), 122.7, 127.3, 127.8, 128.1, 128.6, 128.7, 129.4, 130.4,
137.0, 138.9, 139.4, 146.1, 146.4, 154.0, 158.7 [C6H5, C6H3(iPr)2],
176.4, 176.7 (N-C-N) ppm. 7Li NMR (155.5 MHz, C5D5N, 25 °C):
δ = 3.3 ppm. IR (KBr): ν = 1641 (m), 1578 (s), 1324 (s), 1254 (s),
˜
1212 (s), 1131 (s), 1100 (m), 1043 (s), 976 (s), 886 (s), 831 (m), 783
(m), 695 (s), 638 (s), 487 (s) cm–1.
[Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2]2[Y(thf)](µ-Cl)[Y(CH2SiMe3)]
(3): A solution of Me3SiCH2Li (0.04 g, 0.42 mmol) in toluene
(30 mL) was added to a suspension of 2 (0.72 g, 0.40 mmol) in tolu-
ene (5 mL) at 20 °C, and the reaction mixture was stirred at room
temperature for 1 h. The reaction mixture was filtered, and the sol-
vent was removed in vacuo. The remaining solid was dissolved in a
toluene/hexane mixture (1:10, 40 mL). Slow cooling of this toluene/
hexane solution to –20 °C afforded colorless crystals of 3. The crys-
tals were washed with cold hexane and dried at ambient tempera-
ture in vacuo for 0.5 h. Yield 0.39 g (61%). C88H119ClN8OSi3Y2
(1602.46): calcd. C 65.96, H 7.49, N 6.99, Y 11.10; found C 66.27,
H 7.30, N 6.93, Y 11.02. 1H NMR (400 MHz, C6D6, 25 °C): δ =
2
–1.01 [s, 3 H, Si(CH3)2], –0.64 [s, 3 H, Si(CH3)2], –0.12 [dd, JH,H
Experimental Section
= 11.2, 2JY,H = 3.2 Hz, 1 H, CH2Si(CH3)3], –0.03 [dd, 2JH,H = 11.2,
All experiments were performed in evacuated tubes by using stan-
dard Schlenk techniques, with rigorous exclusion of traces of moist-
ure and air. After being dried over KOH, thf was purified by distil-
lation from sodium/benzophenone ketyl; hexane and toluene were
dried by distillation from sodium/triglyme and benzophenone ketyl
prior to use. C6D6 was dried with sodium/potassium alloy and con-
densed in vacuo into NMR tubes prior to use. C5D5N was dried
with CaH2 and condensed in vacuo into NMR tubes prior to use.
2,6-Diisopropylaniline, Me2SiCl2, and benzonitrile were purchased
from Acros. Anhydrous YCl3,[30] Me3SiCH2Li,[31] and
[(Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2)2Li3]–[Li(thf)4]+[15b] (1) were
prepared according to literature procedures. All other commercially
available chemicals were used after the appropriate purifications.
NMR spectra were recorded with Bruker Avance DRX-400 and
DPX-200 spectrometers in C6D6 or C5D5N at 25 °C, unless other-
wise stated. Chemical shifts for 1H and 13C NMR spectra were
referenced internally to the residual solvent resonances and are re-
ported relative to TMS. IR spectra were recorded as Nujol mulls
with a “Bruker-Vertex 70” instrument. Lanthanide metal analyses
were carried out by complexometric titration. The C, H, N elemen-
tal analyses were performed in the microanalytical laboratory of
the G. A. Razuvaev Institute of Organometallic Chemistry.
3
2JY,H = 3.2 Hz, 1 H, CH2Si(CH3)3], 0.38 [d, JH,H = 6.8 Hz, 3 H,
CH(CH3)2], 0.54 [d, 3JH,H = 6.8 Hz, 3 H, CH(CH3)2], 0.61 [d, 3JH,H
= 6.8 Hz, 3 H, CH(CH3)2], 0.64 [s, 9 H, CH2Si(CH3)3], 0.81 [d,
3
3JH,H = 6.8 Hz, 3 H, CH(CH3)2], 0.83 [d, JH,H = 6.8 Hz, 3 H,
CH(CH3)2], 0.87 [d, 3JH,H = 6.8 Hz, 3 H, CH(CH3)2], 1.11 [m, 6 H,
Si(CH3)2 and CH(CH3)2], 1.18 [d, 3JH,H = 6.8 Hz, 3 H, CH(CH3)2],
1.23 [s, 3 H, Si(CH3)2], 1.27 [m, 7 H, CH(CH3)2 and β-CH2, thf],
3
3
1.38 [d, JH,H = 6.8 Hz, 3 H, CH(CH3)2], 1.46 [d, JH,H = 6.8 Hz,
3
3 H, CH(CH3)2], 1.50 [d, JH,H = 6.8 Hz, 3 H, CH(CH3)2], 1.65 [d,
3JH,H = 6.8 Hz, 3 H, CH(CH3)2], 1.67 [d, JH,H = 6.8 Hz, 3 H,
3
CH(CH3)2], 1.81 [d, 3JH,H
=
6.8 Hz,
3
H, CH-
(CH3)2], 1.96 [d, 3JH,H = 6.8 Hz, 3 H, CH(CH3)2], 2.98 [sept, 3JH,H
3
= 6.8 Hz, 1 H, CH(CH3)2], 3.13 [sept, JH,H = 6.8 Hz, 2 H,
CH(CH3)2], 3.40 [sept, 3JH,H = 6.8 Hz, 1 H, CH(CH3)2], 3.72 [sept,
3JH,H = 6.8 Hz, 2 H, CH(CH3)2], 3.78, 4.04 (br. s, each 2 H, α-
3
CH2, thf), 4.27 [sept, JH,H = 6.8 Hz, 2 H, CH(CH3)2], 6.64–7.70
(m, together 32 H, Ar). 13C NMR (50 MHz, C6D6, 25 °C): δ = 3.0,
3.3, 7.5, 9.6 [Si(CH3)2], 4.7 [CH2Si(CH3)3], 22.7, 23.2, 23.3, 24.0,
24.3, 24.4, 24.8, 24.9, 25.2, 25.4, 25.6, 25.8, 26.0, 26.8 [CH(CH3)2],
25.0 (β-CH2, thf), 27.5, 27.6, 27.9, 28.0, 28.2, 28.3, 28.4, 28.6
1
[CH(CH3)2], 34.9 [d, JY,C = 38.5 Hz, CH2Si(CH3)3], 71.6 (α-CH2,
thf), 122.6, 122.9, 123.1, 123.4, 123.8, 124.3, 124.4, 124.8, 125.1,
[(Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2)2(YCl)2(µ-Cl)]–[Li(thf)4]+ (2): 125.4, 126.9, 127.5, 128.5, 129.0, 136.4, 136.8, 137.5, 138.2, 138.7,
A solution of [(Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2)2Li3]–[Li(thf)4]+
1660
141.9, 142.0, 142.2, 142.3, 142.8, 142.9, 143.4, 143.6, 143.9 [C6H5,
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 1655–1662

Dinuclear Yttrium Complexes with Silyl-Linked Bis(amidinate) Ligands
e) G. Jeske, L. E. Schock, P. N. Swepston, H. Schumann, T. J.
Marks, J. Am. Chem. Soc. 1985, 107, 8103–8110; f) G. Desur-
mont, Y. Li, H. Yasuda, T. Maruo, N. Kanehisha, Y. Kai, Or-
ganometallics 2000, 19, 1811–1813; g) Z. Hou, Y. Luo, X. Li,
J. Organomet. Chem. 2006, 691, 3114–3121. Hydrosilylation: h)
G. A. Molander, J. A. C. Romero, Chem. Rev. 2002, 102, 2161–
2185; Hydroamination: i) I. Aillaud, J. Collin, J. Hannedouche,
E. Schulz, Dalton Trans. 2007, 5105–5118; j) T. E. Müller, K. C.
Hultzsch, M. Yus, F. Foubelo, M. Tada, Chem. Rev. 2008, 108,
3795–3892; Hydroboration: k) K. N. Harrison, T. J. Marks, J.
Am. Chem. Soc. 1992, 114, 9220–9221; l) E. A. Bijpost, R. Du-
chateau, J. H. Teuben, J. Mol. Catal. 1995, 95, 121–128.
a) M. E. Thompson, S. M. Baxter, A. R. Bulls, B. J. Burger,
M. C. Nolan, B. D. Santarsiero, W. P. Schaefer, J. E. Bercaw, J.
Am. Chem. Soc. 1987, 109, 203–219; b) M. Booij, B.-J. Deel-
man, R. Duchateau, D. S. Postma, A. Mettsma, J. H. Teuben,
Organometallics 1993, 12, 3531–3540; c) K. H. den Haan, Y.
Wielstra, J. H. Teuben, Organometallics 1987, 6, 2053–2060; d)
F.-G. Fontaine, T. Don Tilley, Organometallics 2005, 24, 4340–
4342; e) P. L. Watson, J. Am. Chem. Soc. 1983, 105, 6491–6493;
f) H. M. Dietrich, H. Grove, K. W. Törnroos, R. Anwander, J.
Am. Chem. Soc. 2006, 128, 1458–1459.
C H (iPr) ], 176.2, 177.2, 177.8, 178.7 (N-C-N) ppm. IR (KBr): ν
˜
6
3
2
= 1626 (s), 1578 (m), 1318 (s), 1251 (s), 1209 (m), 1131 (m), 1100
(s), 1043 (m), 976 (s), 862 (m), 825 (s), 777 (s), 698 (m), 638 (s),
487 (s) cm–1.
[Me2Si{NC(Ph)N(2,6-iPr2–C6H3)}2Y(µ-H)]2 (5): A solution of Me3-
SiCH2Li (0.06 g, 0.64 mmol) in toluene (30 mL) was added to a
suspension of 2 (0.54 g, 0.30 mmol) in toluene (5 mL) at 20 °C, and
the reaction mixture was stirred for 12 h at 0 °C and for 3 h at room
temperature. The reaction mixture was filtered, and the filtrate was
concentrated to 5 mL. PhSiH3 (0.07 g, 0.65 mmol) was added at
–40 °C, and the clear solution was stirred for 1 h at room tempera-
ture. Growth of colorless crystals of 5 started in approximately
0.5 h. The toluene solution was allowed to stand at –20 °C for 3
days, and the mother liquor was decanted from the crystalline ma-
terial. The colorless crystals were washed with cold hexane and
dried at ambient temperature in vacuo for 1 h. Yield 0.31 g (73%).
C80H102N8Si2Y2 (1409.70): calcd. C 68.16, H 7.29, N 7.95, Y 12.61;
[3]
found C 68.70, H 7.18, N 7.88, Y 12.72. IR (KBr): ν = 1631 (s),
˜
1578 (s), 1248 (s), 1216 (s), 1133 (s), 1098 (s), 972 (s), 932 (m), 916
(m), 894 (s), 828 (s), 776 (m), 625 (m), 541 (s), 489 (s) cm–1.
[4]
[5]
A. D. Sadow, T. Don Tilley, Angew. Chem. Int. Ed. 2003, 42,
803–805.
X-ray Crystallography: The data were collected with a SMART
APEX diffractometer (graphite-monochromated, Mo-Kα-radia-
tion, ω- and θ-scan technique, λ = 0.71073 Å, T = 100 K). The
structures were solved by direct methods and were refined on F2
with the SHELXTL[32] package. All non-hydrogen atoms atom
were found from Fourier syntheses of electron density and were
refined anisotropically, whereas all H atoms in 2, 3, and 5 were
placed in calculated positions and were refined in the riding model.
The hydride H(1) in 5 was found from Fourier syntheses of electron
density and was refined isotropically with fixed Uiso (0.08 Å2). SA-
DABS[33] was used to perform area-detector scaling and absorption
corrections. The details of crystallographic, collection, and refine-
ment data are shown in Table 1. CCDC-756183, -756184, -756185
contain the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
a) E. L. Werkema, E. Messines, L. Perrin, L. Maron, O. Eis-
enstein, R. A. Andersen, J. Am. Chem. Soc. 2005, 127, 7781–
7795; b) L. Maron, E. L. Werkema, L. Perrin, O. Eisenstein,
R. A. Andersen, J. Am. Chem. Soc. 2005, 127, 279–292.
a) F. T. Edelmann, D. M. M. Freckmann, H. Schumann,
Chem. Rev. 2002, 102, 1851–1896; b) W. E. Piers, D. J. H. Em-
slie, Coord. Chem. Rev. 2002, 233–234; W. E. Piers, D. J. H. Em-
slie, Coord. Chem. Rev. 2002, 131–155; c) P. Mountford, B. D.
Ward, Chem. Commun. 2003, 1797–1803; d) A. Trifonov, Russ.
Chem. Rev. 2007, 76, 1051–1072.
[6]
[7]
[8]
a) F. T. Edelmann, Adv. Organomet. Chem. 2008, 57, 183–352;
b) M. P. Coles, Dalton Trans. 2006, 985–1001.
For reviews see: F. T. Edelmann, Chem. Soc. Rev. 2009, 38,
2253–2268; a) R. Duchateau, C. T. Van Wee, A. Meetsma, P. T.
Van Duijnen, J. H. Teuben, Organometallics 1996, 15, 2279–
2290; b) R. Duchateau, C. T. Van Wee, A. Meetsma, J. H.
Teuben, J. Am. Chem. Soc. 1993, 115, 4931–4932; c) R. Duch-
ateau, C. T. Van Wee, J. H. Teuben, Organometallics 1996, 15,
2291–2302; d) J. R. Hagadorn, J. Arnold, Organometallics
1996, 15, 984–991; e) S. Bambirra, M. J. R. Brandsma, E. A. C.
Brussee, A. Meetsma, B. Hessen, J. H. Teuben, Organometallics
2000, 19, 3197–3204; f) S. Bambirra, D. van Leusen, A.
Meetsma, B. Hessen, J. H. Teuben, Chem. Commun. 2003, 522–
523; g) S. Bambirra, M. W. Bouwkamp, A. Meetsma, B.
Hessen, J. Am. Chem. Soc. 2004, 126, 9182–9183; h) S. Bam-
birra, F. Perazzolo, S. J. Boot, T. J. J. Sciarone, A. Meetsma, B.
Hessen, Organometallics 2008, 27, 704–712.
Acknowledgments
This work is supported by the Russian Foundation for Basic Re-
search (Grant Nos. 08-03-00391-a, 06-03-32728), Program of the
Presidium of the Russian Academy of Science (RAS), and the RAS
Chemistry and Material Science Division.
[9]
S. Bambirra, M. J. R. Brandsma, E. A. C. Brussee, A.
Meetsma, B. Hessen, J. H. Teuben, Organometallics 2000, 19,
3197–3204.
S. Bambirra, H. Tsurugi, D. van Leusen, B. Hessen, Dalton
Trans. 2006, 1157–1161.
S. Ge, A. Meetsma, B. Hessen, Organometallics 2008, 27, 3131–
3135.
E. A. Bijpost, R. Duchateau, J. H. Teuben, J. Mol. Catal. A
1995, 95, 121–128.
L. Zhang, M. Nishiura, M. Yuki, Y. Luo, J. Hou, Angew.
[1] a) S. A. Cotton, Coord. Chem. Rev. 1997, 160, 93–127; b) M. N.
Bochkarev, L. N. Zakharov, G. S. Kalinina, Organoderivatives
of Rare Earth Elements, Kluwer Academic Publishers, Dord-
recht, 1995, p. 532; c) H. Schumann, J. A. Meese-Marktschef-
fel, L. Esser, Chem. Rev. 1995, 95, 865–893; d) S. Arndt, J.
Okuda, Chem. Rev. 2002, 102, 1953–1976; e) J. Okuda, Dalton
Trans. 2003, 2367–2378; f) P. M. Zeimentz, S. Arndt, B. R. El-
vidge, J. Okuda, Chem. Rev. 2006, 106, 2404–2433; g) M. Kon-
kol, J. Okuda, Coord. Chem. Rev. 2008, 252, 1577–1591; h) Z.
Hou, M. Nishiura, T. Shima, Eur. J. Inorg. Chem. 2007, 2535–
2545.
[2] Hydrogenation: a) G. Jeske, H. Lauke, H. Mauermann, H.
Schumann, T. J. Marks, J. Am. Chem. Soc. 1985, 107, 8111–
8118; b) V. P. Conticello, L. Brard, M. A. Giardello, Y. Tsyji,
M. Sabat, C. L. Stern, T. J. Marks, J. Am. Chem. Soc. 1992,
114, 2761–2762; Polymerization: c) G. Jeske, H. Lauke, H.
Mauermann, P. N. Swepston, H. Schumann, T. J. Marks, J.
Am. Chem. Soc. 1985, 107, 8091–8103; d) H. Mauermann,
P. N. Swepston, T. J. Marks, Organometallics 1985, 4, 200–202;
[10]
[11]
[12]
[13]
[14]
Chem. Int. Ed. 2008, 47, 2642–2645.
a) C. M. Fendrick, L. D. Schertz, V. W. Day, T. J. Marks, Orga-
nometallics 1988, 7, 1828–1838; b) C. M. Fendrick, E. A.
Mintz, L. D. Schertz, T. J. Marks, V. W. Day, Organometallics
1984, 3, 819–821.
a) J.-F. Li, L.-H. Weng, X.-H. Wei, D.-S. Liu, J. Chem. Soc.,
Dalton Trans. 2002, 1401–1405; b) S.-D. Bai, J.-P. Guo, D.-S.
Liu, Dalton Trans. 2006, 2244–2250; c) M. S. Hill, P. B. Hitch-
cock, S. M. Mansell, Dalton Trans. 2006, 1544–1553.
[15]
Eur. J. Inorg. Chem. 2010, 1655–1662
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
1661

A. A. Trifonov et al.
FULL PAPER
[16] a) S. Bambirra, A. Meetsma, B. Hessen, J. H. Teuben, Organo-
metallics 2001, 20, 782–785; b) J. Wang, Y. Yao, Y. Zhang, Q.
Shen, Inorg. Chem. 2009, 48, 744–751; c) C.-L. Pan, W. Chen,
Sh. Song, H. Zhang, X. Li, Inorg. Chem. 2009, 48, 6344–6346.
[17] a) D. Stern, M. Sabat, T. J. Marks, J. Am. Chem. Soc. 1990,
112, 9558–9575; b) N. Höck, W. Oroschin, G. Paolucci, R. D.
Fischer, Angew. Chem. Int. Ed. Engl. 1986, 25, 738–739; c)
M. G. Klimpel, P. Sirsch, W. Scherer, R. Anwander, Angew.
Chem. Int. Ed. 2003, 42, 574–577.
[18] a) J. Wang, H. Sun, Y. Yao, Q. Shen, Polyhedron 2008, 27,
1977–1982; b) J. Wang, F. Xu, T. Cai, Q. Shen, Org. Lett. 2008,
10, 445–448.
[19] a) W. J. Evans, J. W. Grate, K. R. Levan, I. Bloom, T. T. Pe-
terson, R. J. Doedens, H. Zhang, J. L. Aywood, Inorg. Chem.
1986, 25, 3614–3619; b) W. J. Evans, T. T. Peterson, M. D.
Rausch, W. E. Hunter, H. Zhang, J. L. Aywood, Organometal-
lics 1985, 4, 554–559.
[20] M. P. Hogerheide, D. M. Grove, J. Boersma, J. T. B. H. Jastrz-
ebski, H. Kooijman, A. L. Spek, G. van Koten, Chem. Eur. J.
1995, 1, 343–350.
[21] a) P. Voth, T. P. Spaniol, J. Okuda, Organometallics 2003, 22,
3921–3926; b) L. Lavanant, T.-Y. Chou, Y. Chi, C. V.
Lehmann, L. Toupet, J.-F. Carpentier, Organometallics 2004,
23, 5450–5458; c) X. Liu, X. Shang, T. Tang, N. Hu, F. Pei, D.
Cui, X. Chen, X. Jing, Organometallics 2007, 26, 2747–2757;
d) A. A. Trifonov, T. P. Spaniol, J. Okuda, Organometallics
2001, 20, 4869–4874.
[23]
a) K. C. Hultzsch, T. P. Spaniol, J. Okuda, Angew. Chem. Int.
Ed. 1999, 38, 227–230; b) S. Arndt, P. Voth, T. P. Spaniol, J.
Okuda, Organometallics 2000, 19, 4690–4700.
W. J. Evans, J. H. Meadows, A. L. Wayda, W. E. Hunter, J. L.
Atwood, J. Am. Chem. Soc. 1982, 104, 2008–2014.
W. J. Evans, D. K. Drummond, T. P. Hanusa, R. J. Doedens,
Organometallics 1987, 6, 2279–2285.
W. P. Kretschmer, S. I. Troyanov, A. Meetsma, B. Hessen, J. H.
Teuben, Organometallics 1998, 17, 284–286.
A. A. Trifonov, G. G. Skvortsov, D. M. Lyubov, N. A. Skorod-
umova, G. K. Fukin, E. V. Baranov, V. N. Glushakova, Chem.
Eur. J. 2006, 12, 5320–5327.
A. A. Trifonov, T. P. Spaniol, J. Okuda, Organometallics 2001,
20, 4869–4874.
[24]
[25]
[26]
[27]
[28]
[29] D. M. Lubov, A. M. Bubnov, G. K. Fukin, F. M. Dolgushin,
M. Yu. Antipin, O. Pelce, M. Schappacher, S. M. Guillaume,
A. A. Trifonov, Eur. J. Inorg. Chem. 2008, 2090–2098.
[30] M. D. Taylor, C. P. Carter, J. Inorg. Nucl. Chem. 1962, 24, 387–
393.
[31] H. L. Lewis, T. L. Brown, J. Am. Chem. Soc. 1970, 92, 4664–
4670.
[32] G. M. Sheldrick, SHELXTL, v. 6.12, Structure Determination
Software Suite, Bruker AXS, Madison, Wisconsin (USA),
2000.
[33] G. M. Sheldrick, SADABS, v.2.01, Bruker/Siemens Area De-
tector Absorption Correction Program, Bruker AXS, Madison,
Wisconsin (USA), 1998.
[22] A. Z. Voskoboinikov, I. N. Parshina, A. K. Shestakova, K. P.
Butin, I. P. Beletskaya, L. G. KuzЈmina, J. A. K. Howard, Or-
ganometallics 1997, 16, 4041–4055.
Received: December 1, 2009
Published Online: March 3, 2010
1662
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 1655–1662