New potentially tridentate amidinate ligand {o-MeOC6H 4NC(Ph)N(SiMe3)}-. Synthesis and molecular structures of amidinate complexes of lithium [{o-MeOC6H 4NC(Ph)N(SiMe3)}Li]2

Article abstract of DOI:10.1007/s11172-011-0128-5

The reaction of lithium silylamide ['o-MeOC₆H ₄N(SiMe₃)}Li(OEt₂)]₂ with 2 equiv. of benzonitrile in THF at ～20 °C affords the lithium derivative of the new tridentate amidinate ligand [{o-MeOC₆

Full text of DOI:10.1007/s11172-011-0128-5

Russian Chemical Bulletin, International Edition, Vol. 60, No. 5, pp. 803—808, May, 2011
803
New potentially tridentate amidinate ligand
{oꢀMeOC6H4NC(Ph)N(SiMe3)}–. Synthesis and molecular structures of
amidinate complexes of lithium [{oꢀMeOC6H4NC(Ph)N(SiMe3)}Li]2
and yttrium [{oꢀMeOC6H4NC(Ph)N(SiMe3)}YCl2(THF)2]2*
V. Yu. Rad´kov,a G. G. Skvortsov,a G. K. Fukin,a K. A. Lyssenko,b M. Yu. Antipin,b and A. A. Trifonova
aG. A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences,
49 ul. Tropinina, 603950 Nizhny Novgorod, Russian Federation.
Fax: +7 (831) 266 1497. Еꢀmail: trif@iomc.ras.ru
bA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5085
The reaction of lithium silylamide [{oꢀMeOC6H4N(SiMe3)}Li(OEt2)]2 with 2 equiv. of
benzonitrile in THF at ~20 °C affords the lithium derivative of the new tridentate amidinate
ligand [{oꢀMeOC6H4NC(Ph)N(SiMe3)}Li]2. The Xꢀray diffraction study showed that this complex
has a dimeric structure due to the coordination of the N atoms and the ether group of one amidꢀ
inate ligand to different Li atoms. The reaction of anhydrous YCl3 with the resulting complex in
THF gives the monoamidinate complex [{oꢀMeOC6H4NC(Ph)N(SiMe3)}YCl2(THF)2]2 reꢀ
gardless of the reagent ratio. The latter has a dimeric structure in the crystalline state as a result
of the presence of two μ ꢀbridging Cl atoms that link Y atoms. The ether groups of the amidꢀ
2
inate ligands are not involved in the metal—ligand interaction.
Key words: rareꢀearth metals
, amidinate ligand, lithium amidinate complexes, yttrium
amidinate complexes synthesis, structure
,
.
The amidinate ligands [RC(NR´)2]– belonging to
monoanionic fourꢀelectron ligands, in which the negative
charge in delocalized over the NCN group, have attracted
researchers' attention in the last three decades due to diꢀ
verse coordination properties. In addition, the obvious adꢀ
vantages of amidinate ligands are that their electronic and
steric properties can be easily modified by varying the subꢀ
stituents both at the N atoms and the central C atom, as
well as that the starting reagents for their preparation are
available and relatively cheap. Recent studies have shown
the great synthetic potential of amidinate ligands in coorꢀ
dination chemistry of a large number of elements.1—6 Data
on amidinate ligands in organolanthanide chemistry pubꢀ
lished in the works of Edelmann7—11 and Teuben12—17
have greatly stimulated the development of this field and
made it possible to synthesize and characterize various
classes of their derivatives. Highly reactive alkyl, cationic
alkyl, and hydride complexes of rare earth metals show the
ability to catalyze a series of transformations of unsaturatꢀ
ed substrates, such as polymerization of olefins15,16 and
dienes,18 selective dimerization of monosubstituted acetylꢀ
enes,19 hydroboration,20 hydrosilylation,21 and hydroꢀ
amination22 of olefins.
It is known that the stability and reactivity of organic
derivatives of rare earth metals are determined to a large
extent by the coordinative and steric saturation of the metal
coordination sphere. Therefore, considerable efforts are
currently focused on searching for new types of ligand
systems, which can stabilize metal complexes and provide
additional ways to design the coordination environment
of the central metal atom and control the reactivity.23,24
One of approaches to this problem is based on the introꢀ
duction of additional groups, which have Lewis base propꢀ
erties and can be coordinated to a metal atom, into the
ligand system, resulting in the saturation of the coordinaꢀ
tion sphere and a change in its geometry. Several amidiꢀ
nate ligands containing electronꢀdonating groups in the
side chain are documented.25—28 The aims of the present
study were to design a new nonꢀsymmetrical amidinate
ligand {oꢀMeOC6H4NC(Ph)N(SiMe3)}, in which one of
the N atoms contains the ether group capable of coordiꢀ
nating to the metal atom, as well as to synthesize lithium
and yttrium complexes based on this ligand.
* Dedicated to Academician V. N. Charushin on the occasion of
his 60th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 785—790, May, 2011.
1066ꢀ5285/11/6005ꢀ803 © 2011 Springer Science+Business Media, Inc.

804
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 5, May, 2011
Rad´kov et al.
Results and Discussion
Si(1)
O(1´)
One of facile methods for the formation of the amidinꢀ
ate (most often benzamidinate) moiety is based on the
reaction of lithium silylamide LiN(SiMe3)2 with nitrile
RC≡N,29,30 resulting in the formation of the correspondꢀ
ing lithium amidinate {RC(NSiMe3)2}Li. This method
allows one to prepare functionalized amidinate ligands
containing the pyridyl and furyl moieties.31 We used this
method for the synthesis of a new potentially tridentate
amidinate ligand.
Li(1)
N(2´)
N(1´)
N(1)
Li(2)
N(2)
Si(1´)
It was found that the reaction of the dimeric lithium
silylamide [{oꢀMeOC6H4N(SiMe3)}Li(OEt2)]2 (see Ref. 32)
with 2 equiv. of benzonitrile in THF at ~20 °C affords the
lithium complex [{oꢀMeOC6H4NC(Ph)N(SiMe3)}Li]2 (1)
containing the new amidinate ligand (Scheme 1). The
reaction proceeds through the addition of lithium amide
at the triple bond C≡N of benzonitrile followed by the
migration of the SiMe3 moiety. After the recrystallization
of the reaction product from hexane, complex 1 was obꢀ
tained as transparent crystals in 86% yield.
O(1)
Fig. 1. Structure of complex 1.
of the ether groups of one ligand to different Li atoms. It is
interesting that, in spite of the presence of diethyl ether
molecules in the starting amide and the occurrence of the
reaction in THF, complex 1 does not contain coordinated
donor solvent molecules. The coordination sphere of the
Li atoms in complex 1 is formed by three N atoms of two
amidinate moieties and the O atom of the ether group,
resulting in the formal coordination number 4. It should
be noted that the coordination of the amidinate moieties
to the Li atom in the structure of 1, as opposed to deriꢀ
vatives of benzamidinate ligands,27 is strongly distorted,
and the Li—N bond lengths in the metallacycles LiNCN
are substantially different: Li(1)—N(1), 1.963(3) Å;
Li(1)—N(2), 2.401(3) Å; Li(2)—N(2´), 2.025(2) Å;
Li(2)—N(1´), 1.973(2) Å. The Li—O bond lengths are
1.957(3) and 1.914(2) Å.
Scheme 1
In the 1H NMR spectrum of complex 1 (C6D6, 20 °C),
the protons of the trimethylsilyl group appear as a singlet
at δ 0.22, a singlet at δ 3.31 is assigned to the protons of the
methoxy group, and signals for aromatic protons appear
as a multiplet in low field (δ 6.34—7.49). In the 13C NMR
spectrum, the signal for the quaternary C atom of the
amidinate moiety is observed in the characteristic region
at δ 176.8, the signal for the C atoms of the trimethylsilyl
Table 1. Selected bond lengths (d) and bond angles (ω) in comꢀ
plex 1
Complex 1 is highly sensitive to atmospheric oxygen
and moisture and is readily soluble in ethereal solvents and
aromatic and aliphatic hydrocarbons.
Bond
d/Å
Angle
ω/deg
Transparent crystals of complex 1 suitable for Xꢀray
diffraction were grown by slow cooling of a hexane soluꢀ
tion to –20 °C. The molecular structure of complex 1 is
shown in Fig. 1. Selected bond lengths and bond angles
are given in Table 1.
The Xꢀray diffraction study showed that lithium amidꢀ
inate complex 1 has a dimeric structure due to the coordiꢀ
nation of the N atoms of the NCN group and the O atoms
Li(1)—N(1)
Li(1)—N(2)
Li(1)—N(2´) 2.025(2)
Li(1)—O(1´) 1.957(3)
Li(2)—N(2)
Li(2)—N(2´) 2.160(3)
Li(2)—N(1´) 1.973(2)
1.963(3)
2.401(3)
N(1)—Li(1)—N(2´) 137.08(14)
O(1´)—Li(1)—N(2)
N(1)—Li(1)—N(2)
83.30(10)
62.29(8)
N(2´)—Li(1)—N(2) 100.32(11)
Li(2)—N(2)—Li(1) 70.75(9)
O(1)—Li(2)—N(1´) 121.12(13)
O(1)—Li(2)—N(2) 84.50(10)
O(1)—Li(2)—N(2´) 142.63(13)
2.014(2)
Li(2)—O(1)
1.914(2)

Synthesis and structures of amidinate complexes
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 5, May, 2011
805
Scheme 2
groups appear at δ 1.7, and the signal for the C atoms of the
methoxy group is observed at δ 54.3. In the IR spectrum,
the intense absorption band of C≡N at 2300 cm–1 is abꢀ
sent; instead, the absorption band at 1620 cm–1 assigned
to the double bond of the amidinate moiety appears.
To study the coordination of the new tridentate amidꢀ
inate ligand to a metal atom with a larger ionic radius (in
our case, the Y atom), we investigated the reaction of
anhydrous YCl3 with complex 1 in THF at ~20 °C. It was
found that this reaction affords exclusively the monoꢀ
amidinate derivative regardless of the reagent molar ratio
(YCl3 : 1 = 1 : 1 and 2 : 1). Evidently, the size of the
amidinate ligand prevents the simultaneous coordination
of two moieties to one Y atom. The removal of THF, the
extraction of the reaction product with toluene, and
the separation of a LiCl precipitate followed by recrystalꢀ
lization from THF allowed us to isolate the complex
[{oꢀMeOC6H4NC(Ph)N(SiMe3)}YCl2(THF)2]2 (2) in
69% yield (Scheme 2).
Transparent crystals of complex 2 suitable for Xꢀray
diffraction study were prepared by slow evaporation of
a solution of complex 2 in THF to –20 °C. The molecular
structure of complex 2 is shown in Fig. 2. Selected bond
lengths and bond angles are given in Table 2.
The Xꢀray diffraction study showed that compound 2
has a dimeric structure due to the μ2ꢀbridging coordinaꢀ
tion of two Cl atoms to two Y atoms, whereas two other Cl
atoms are terminal. Complex 2 is neutral and does not
contain LiCl in the form of the ate complex. The coordiꢀ
nation sphere of the Y atom is formed by two N atoms of
the amidinate moiety, three Cl atoms, and two O atoms of
THF molecules, resulting in the coordination number 7
for the Y atom. According to the Xꢀray diffraction data,
the O atom of the ether group in complex 2 is not coordiꢀ
nated to the Y atom. The bridging Y—Cl bonds in the
structure of 2 (2.7262(6), 2.7765(6), 2.7764(6) Å) are, as
expected, substantially longer than the terminal bonds
(2.5082(6) Å); their lengths are comparable with the averꢀ
age length of the bridging bonds in the sevenꢀcoordinate
complex [Y(η5:η1ꢀC5Me4SiMe2NCMe2R)(THF)(μꢀCl)]2
(2.736(2) Å).33 The Y—N bond lengths in the metallaꢀ
cycle YNCN (2.384(2) and 2.375(2) Å) are in the range
Si(1A)
N(2A)
O(1A)
C(8A)
N(1A)
O(3A)
Cl(2A)
O(2)
Cl(1)
Y(1A)
Y(1)
N(1)
Cl(1A)
Cl(2)
O(3)
O(2A)
O(1)
C(8)
N(2)
Si(1)
Fig. 2. Structure of complex 2.

806
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 5, May, 2011
Rad´kov et al.
Table 2. Selected bond lengths (d) and bond angles (ω) in
complex 2
use of standard Schlenk technique. Tetrahydrofuran was dried
with potassium hydroxide followed by distillation over sodium
benzophenone ketyl. Hexane and benzene were dried by refluxꢀ
ing and distillation over metallic Na; C6D6 was dried with meꢀ
tallic Na, degassed, and condensed in vacuo. Lithium amide
[{oꢀC6H4OMeN(SiMe3)}Li(OEt2)]2 (see Ref. 32) and anhydrous
YCl3 (see Ref. 35) were prepared according to known proꢀ
cedures. oꢀAnisidine and benzonitrile are commercial reꢀ
agents (Acros). oꢀAnisidine was dried with calcium hydride, disꢀ
tilled, and stored in an evacuated container. Benzonitrile
was distilled, dried over molecular sieves, and stored in an evacꢀ
uated container.
The IR spectra were recorded on a BrukerꢀVertex 70 instruꢀ
ment. Samples of the compounds were prepared under dry argon
as Nujol mulls. The 1H, 13C, and 7Li NMR spectra were recorded
on Bruker DPX 200 and 400 instruments (20 °C). The chemical
shifts (ppm) are given with respect to the known shifts of the
residual protons of deuterated solvents.
Bond
d/Å
Angle
ω/deg
Y(1)—O(2)
Y(1)—O(3)
Y(1)—N(2)
Y(1)—N(1)
Y(1)—Cl(1)
Y(1)—Cl(2)
Y(1)—C(8)
2.3664(14) O(2)—Y(1)—O(3)
2.3729(16) O(2)—Y(1)—N(2)
2.3748(17) O(3)—Y(1)—N(2)
2.3839(17) O(2)—Y(1)—N(1)
87.98(6)
131.87(6)
85.21(6)
75.44(6)
85.43(6)
56.55(6)
96.54(5)
90.52(5)
2.5802(6)
2.7262(6)
2.746(2)
O(3)—Y(1)—N(1)
N(2)—Y(1)—N(1)
N(2)—Y(1)—Cl(1)
N(1)—Y(1)—Cl(1)
Y(1)—Cl(2A) 2.7765(6)
Cl(2)—Y(1A) 2.7764(6)
Y(1)—Cl(2)—Y(1A) 107.071(18)
N(1)—C(8)
N(2)—C(8)
1.326(3)
1.335(3)
N(1)—C(8)—N(2)
C(8)—N(1)—Y(1)
115.80(18)
90.89(12)
Bis[(NꢀtrimethylsilylꢀN´ꢀoꢀmethoxyphenylbenzamidinato)ꢀ
lithium], [{oꢀMeOC6H4NC(Ph)N(SiMe3)}Li]2 (1). A solution
of PhCN (0.25 g, 2.40 mmol) in THF (3 mL) was added
to a solution of [{oꢀC6H4OMeN(SiMe3)}Li(OEt2)]2 (0.67 g,
1.2 mmol) in THF (30 mL). The reaction mixture was stirred at
~20 °C for 24 h. Then THF was removed, and the oily residue
was dissolved in hexane. After cooling of the concentrated hexane
solution to –20 °C, transparent crystals of complex 1 were obꢀ
tained in a yield of 0.68 g (86%). Found (%): C, 66.73; H, 6.77;
N, 9.03. C17H21LiN2OSi. Calculated (%): C, 67.08; H, 6.95;
N, 9.20. 1H NMR (C6D6), δ: 0.22 (s, 18 H, SiMe3); 3.31 (s, 6 H,
OMe); 6.33 (m, 2 H, C6H4); 6.54 (m, 4 H, PhCN); 6.61 (m, 2 H,
PhCN); 7.00 (d, 6 H, C6H4); 7.47 (d, 4 H, PhCN). 13C NMR
(C6D6), δ: 1.7 (SiMe3); 54.3 (OMe); 109.2, 118.1, 121.1, 124.4,
141.5, 149.9 (C6H4); 126.7, 126.9, 127.1, 127.8 (Ph); 176.8
(NCN). 7Li NMR (C6D6), δ: 5.06. IR (Nujol), ν/cm–1: 1633
(w), 1517 (s), 1242 (s), 1105 (m), 964 (s), 852 (s), 765 (m).
Bis[(NꢀtrimethylsilylꢀN´ꢀoꢀmethoxyphenylbenzamidinato)ꢀ
(dichlorido)di(tetrahydrofuran)yttrium], [{oꢀMeOC6H4NC(Ph)ꢀ
N(SiMe3)}YCl2(THF)2]2 (2). A solution of 1 (0.524 g, 1.72 mmol)
in THF (50 mL) was added to a suspension of anhydrous YCl3
(0.336 g, 1.72 mmol) in THF (10 mL). The reaction mixture was
stirred at ~20 °C for 24 h. Then THF was removed in vacuo, the
solid reside was extracted with toluene, and the extract was filꢀ
tered to separate LiCl. Toluene was removed by condensation
in vacuo, and the solid residue was dried in vacuo to constant
weight. The recrystallization of the solid residue from THF gave
yellow crystals of 2 in a yield of 0.71 g (69%). Found (%):
C, 49.60; H, 6.05; N, 4.39; Y, 14.90. C50H74Cl4N4O6Si2Y2.
characteristic of yttrium derivatives with guanidinate and
amidopyridinate ligands.34 The C—N bond lengths in the
amidinate moiety are equivalent: C(8)—N(1), 1.326(3) Å;
C(8)—N(2), 1.335(3) Å. This is indicative of delocalizaꢀ
tion of the negative charge in the NCN group.
In the 1H NMR spectrum of complex 2 (C6D6, 20 °C),
the singlet at δ 0.25 corresponds to protons of the trimethylꢀ
silyl group, the βꢀprotons of four THF molecules appear
as a singlet at δ 1.40, and the protons of the methoxy group
together with the αꢀprotons of four THF molecules give
a singlet at δ 3.70 The aromatic protons appear as a set of
lowꢀfield signals (δ 6.20—7.21).
With the aim of synthesizing alkyl complexes of yttrium
in the tridentate amidinate ligand environment, we perꢀ
formed the reactions of complex 2 with Me3SiCH2Li and
MeLi (in the presence of TMEDA). The reaction of comꢀ
plex 2 with Me3SiCH2Li was carried out at 0 °C; the reacꢀ
tion with MeLi was performed in diethyl ether in the presꢀ
ence of TMEDA at 0 °C. The occurrence of the transforꢀ
mations was evidenced by the precipitation of LiCl. Howꢀ
ever, we failed to isolate the corresponding alkyl derivaꢀ
tives. Soluble reaction products were brown oily liquids of
unknown composition.
To sum up, we found that the reaction of lithium silylꢀ
amide [{oꢀMeOC6H4N(SiMe3)}Li(OEt2)]2 with 2 equiv.
of benzonitrile in THF at ~20 °C affords the lithium
derivative of the new tridentate amidinate ligand
[{oꢀMeOC6H4NC(Ph)N(SiMe3)}Li]2 (1). The reaction of
anhydrous YCl3 with complex 1 in THF gives the monoꢀ
amidinate complex [{oꢀMeOC6H4NC(Ph)N(SiMe3)}ꢀ
YCl2(THF)2]2 (2) regardless of the reagent ratio. Compꢀ
lex 2 has a dimeric structure in the crystalline state due to
the presence of two μ2ꢀbridging Cl atoms that link Y atoms.
The ether groups of the amidinate ligands are not involved
in the metal—ligand interaction.
1
Calculated (%): C, 49.92; H, 6.20; N, 4.66; Y, 14.78. H NMR
(C6D6), δ: 0.24 (s, 18 H, SiMe); 1.38 (s, 16 H, βꢀCH2, THF);
3.70 (br.s, 22 H, 16 H, αꢀCH2, THF and 6 H, oꢀC6H4(OMe));
6.20 (d, 1 H, C6H4); 6.32 (d, 2 H, oꢀC6H4); 6.49 (m, 5 H,
oꢀC6H4); 6.88 (s, 7 H, Ph); 7.21 (s, 3 H, Ph). 13C NMR
(pyridineꢀd5), δ: 2.1, 3.6 (SiMe3); 25.8 (βꢀCH2, THF); 55.8
(
oꢀC6H4(OMe)); 67.9 (αꢀCH2, THF); 113.1, 121.8, 124.0,
128.0, 128.5, 130.5, 136.8, 139.6, 152.0, 156.0 (C6H4, Ph);
158.6 (NCN). IR (Nujol), ν/cm–1: 1626 (w), 1245 (m), 1182
(m), 1043 (s), 1013 (s), 856 (s), 677 (m).
Xꢀray diffraction study. Xꢀray diffraction study of complex 1
was performed at 100 K on a SMART APEX II CCD diffractoꢀ
meter (λ(MoꢀKα) = 0.71072 Å, ωꢀscanning technique). The
structure was solved by direct methods and refined by the fullꢀ
matrix leastꢀsquares method with anisotropic displacement paꢀ
Experimental
All operations associated with the synthesis and isolation of
the products were carried out in evacuated glassware with the

Synthesis and structures of amidinate complexes
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 5, May, 2011
807
Table 3. Crystallographic parameters and the Xꢀray data collecꢀ
tion and refinement statistics for complexes 1 and 2
This study was financially supported by the Russian
Foundation for Basic Research (Project Nos 08ꢀ03ꢀ00391
and 11ꢀ03ꢀ00555).
Parameter
1
2
References
Molecular formula
Molecular weight
Space group
a/Å
b/Å
c/Å
C17H21LiN2OSi C50H74Cl4N4O6Si2Y2
304.39
P21/c
1202.94
P21/n
1. F. T. Edelmann, Coord. Chem. Rev., 1994, 137, 403.
2. J. Barker, M. Kilner, Coord. Chem. Rev., 1994, 133, 219.
3. M. P. Coles, J. Chem. Soc., Dalton Trans., 2006, 985.
4. D. A. Kisun´ko, M. V. Zabalov, G. P. Brusova, D. A.
Lemenovskii, Usp. Khim., 2006, 75, 395 [Russ. Chem. Rev.
(Engl. Transl.), 2006, 75].
5. F. T. Edelmann, Adv. Organomet. Chem., 2008, 57, 183.
6. F. T. Edelmann, Chem. Soc. Rev., 2009, 38, 2253.
7. C. Hagen, H. Reddmann, H.ꢀD. Amberger, F. T. Edelmann,
U. Pegelow, G. V. Shalimoff, N. M. Edelstein, J. Organomet.
Chem., 1993, 462, 69.
8. M. Wedler, F. Knosel, U. Pieper, D. Stalke, F. T. Edelꢀ
mann, H.ꢀD. Amberger, Chem. Ber., 1992, 125, 2171.
9. A. Recknagel, F. Knosel, H. Gornitzka, M. Noltemeyer, F. T.
Edelmann, U. Behrens, J. Organomet. Chem., 1991, 417, 363.
10. M. Wedler, M. Noltemeyer, U. Pieper, D. Schmidt, H.ꢀG.
Stalke, F. T. Edelmann, Angew. Chem., Int. Ed. Engl., 1990,
29, 894.
11. M. Wedler, A. Recknagel, J. W. Gilje, M. Notelmeyer, F. T.
Edelmann, J. Organomet. Chem., 1992, 426, 295.
12. R. Duchateau, C. T. van Wee, A. Meetsma, P. T. van
Duijnen, J. H. Teuben, Organometallics, 1996, 15, 2279.
13. R. Duchateau, C. T. van Wee, A. Meetsma, J. H. Teuben,
J. Am. Chem. Soc., 1993, 115, 4931.
15.6597(8)
11.7281(6)
19.6459(10)
90.00
9.8406(5)
13.6738(8)
21.6449(12)
90
α/deg
β/deg
91.3356(10)
90.00
93.4160(10)
90
γ/deg
V/Å–3
3607.2(3)
4
2907.3(3)
2
Z
dcalc/g cm–3
1.121
1.374
μ/mm–1
1.31
2.258
θꢀScan range, deg
Number of measured
reflections
Number of reflections
with I > 2σ(I)
Rint
1.30—29.00
36030
1.76—27.00
18552
9590
4987
0.0310
1.036
0.0311
1.006
GOOF (F2)
R1 (I > 2σ(I))
ωR2 (all data)
Residual electron
density
0.0413
0.0340
0.1253
0.0521
0.390/–0.239
0.660/–0.323
(max/min)/e Å–3
14. R. Duchateau, C. T. van Wee, J. H. Teuben, Organometalꢀ
lics, 1996, 15, 2291.
15. S. Bambirra, D. van Leusen, A. Meetsma, B. Hessen, J. H.
Teuben, Chem. Commun., 2003, 522.
16. S. Bambirra, M. W. Bouwkamp, A. Meetsma, J. H. Hessen,
J. Am. Chem. Soc., 2004, 126, 9182.
17. S. Bambirra, F. Perazzolo, S. J. Boot, T. J. J. Sciarone,
A. Meetsma, B. Hessen, Organometallics, 2008, 27, 704.
18. L. Zhang, M. Nishiura, M. Yuki, Y. Luo, Z. Hou, Angew.
Chem., Int. Ed. Engl., 2008, 47, 2642.
rameters for all nonhydrogen atoms based on F 2hkl. The hydroꢀ
gen atoms were positioned geometrically and refined isotropiꢀ
cally with fixed thermal parameters Uiso = 1.2Ciso. An analysis of
difference electron density maps showed that one of SiMe3 groups
in the structure of 1 is disordered over two positions with equal
occupancy. The positions of the carbon atoms of the disordered
group were refined anisotropically with the Si—C bond lengths
and anisotropic displacement parameters restrained to be equal
(Eadp instructions). The calculations were carried out with the
use of the SHELXTL 5.102 program package.36
19. R. Duchateau, C. T. van Wee, J. H. Teuben, Organometalꢀ
lics, 1996, 15, 2291.
The Xꢀray diffraction study of complex 2 was performed
on a SMART APEX I diffractometer (graphite monochromaꢀ
tor, MoꢀKα radiation, ϕ—ωꢀscanning technique) at 100 K. The
structure was solved by direct methods and refined by the
fullꢀmatrix leastꢀsquares method with anisotropic displacement
parameters for all nonhydrogen atoms based on F 2hkl. The
hydrogen atoms were positioned geometrically and refined using
a riding model. All calculations were carried out with the use of
the SHELXTL v. 6.10 program package.36 The absorption corꢀ
rection was applied with the use of the Sadabs program.37 Prinꢀ
cipal crystallographic parameters and the Xꢀray data collection
and structure refinement statistics for complexes 1 and 2 are
given in Table 3.*
20. E. A. Bijpost, R. Duchateau, J. H. Teuben, J. Mol. Catal.,
1995, 95, 121.
21. S. Ge, A. Meetsma, B. Hessen, Organometallics, 2008,
27, 3131.
22. S. Bambirra, H. Tsurugi, D. van Leusen, B. Hessen, J. Chem.
Soc., Dalton Trans., 2006, 1157.
23. W. E. Piers, D. J. H. Emslie, Coord. Chem. Rev., 2002,
233—234, 131.
24. A. A. Trifonov, Usp. Khim., 2007, 76, 11 [Russ. Chem. Rev.
(Engl. Transl.), 2007, 76].
25. S. Bambirra, M. J. R. Brandsma, E. A. C. Brussee, A. Meetsꢀ
ma, B. Hessen, J. H. Teuben, Organometallics, 2000, 19, 3197.
26. D. Doyle, Yu. Gun´ko, P. B. Hitchkock, M. F. Lappert,
J. Chem. Soc., Dalton Trans., 2000, 4093.
* Additional crystallographic data were deposited with the Camꢀ
bridge Crystallographic Data Centre (CCDC 818268 and
818269) and can be obtained, free of charge, on application to
www.ccdc.cam.uk/data_request/cif.
27. S. Aharonovich, M. Kapon, M. Botoshanski, M. S. Eisen,
Organometallics, 2008, 27, 1869.
28. C.ꢀT. Chen, C.ꢀA. Huang, Y.ꢀR. Tzeng, B.ꢀH. Huang,
J. Chem. Soc., Dalton Trans., 2003, 2585.

808
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 5, May, 2011
Rad´kov et al.
29. A. R. Sanger, Inorg. Nucl. Chem. Lett., 1973, 9, 351.
30. R. T. Boeré, R. T. Oakley, R. W. Reed, J. Organomet. Chem.,
1987, 331, 161.
31. S. Aharonovich, M. Botoshanski, Z. Rabinovich, R. W. Wayꢀ
mouth, M. S. Eisen, Inorg. Chem., 2010, 49, 1220.
32. G. B. Deacon, C. M. Forsyth, N. M. Scott, Eur. J. Inorg.
Chem., 2002, 1425.
35. M. D. Taylor, C. P. Carter, J. Inorg. Nucl. Chem., 1962,
24, 387.
36. G. M. Sheldrick, Acta Crystallogr., 2008, A64, 112.
37. G. M. Sheldrick, SADABS v.2.01, Bruker/Siemens Area
Detector AbsorptionCorrection Program, Bruker AXS, Madison,
Wisconsin, 1998.
33. S. Arndt, P. Voth, T. P. Spaniol, J. Okuda, Organometallics,
2000, 19, 4690.
34. A. Trifonov, Coord. Chem. Rev., 2010, 254, 1327.
Received December 22, 2010;
in revised form March 22, 2011