Synthesis, structural characterization, and reactivity of mono(amidinate) rare-earth-metal bis(aminobenzyl) complexes

Article abstract of DOI:10.1021/om400787j

Three kinds of solvated lithium amidinates with different coordination models were obtained via recrystallization of [PhC(NC₆H ₄ⁱPr₂-2,6)₂]Li(THF) (1a) in different solvents. Treatment of o-Me₂

Full text of DOI:10.1021/om400787j

Article
pubs.acs.org/Organometallics
Synthesis, Structural Characterization, and Reactivity of
Mono(amidinate) Rare-Earth-Metal Bis(aminobenzyl) Complexes
Jianquan Hong,†,‡ Lixin Zhang,*,† Kai Wang,† Zhenxia Chen,† Limin Wu,‡ and Xigeng Zhou*,†,§
†Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai
200433, People’s Republic of China
‡Department of Materials Science, Fudan University, Shanghai 200433, People’s Republic of China
§State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, People’s Republic of China
S
* Supporting Information
ABSTRACT: Three kinds of solvated lithium amidinates with different
i
coordination models were obtained via recrystallization of [PhC(NC6H4 Pr2-
2,6)2]Li(THF) (1a) in different solvents. Treatment of o-Me2NC6H4CH2Li with
LLnCl2(THF)n (2; L = [PhC(NC6H4 Pr2-2,6)2]− (NCNdipp), [o-Me2NC6H4CH2C-
i
i
(NC6H4 Pr2-2,6)2]− (NCNdipp′)) formed in situ from reaction of LnCl3(THF)x
with LLi(THF) gave the rare-earth-metal bis(aminobenzyl) complexes LLn-
(CH2C6H4NMe2-o)2 (L = NCNdipp, Ln = Sc (3a), Y (3b), Lu (3c); L = NCNdipp′,
Ln = Sc (3d), Lu (3e)) in high yields. Reactions of complexes 3 with CO2,
PhNCO, 2,6-diisopropylaniline, and S have been explored. CO2 inserted into each
Ln−C bond of complexes 3a−c to form the dual-core complexes [(NCNdipp)Sc(μ-
η1:η1-O2CCH2C6H4NMe2-o)2]2 (4a) and [(NCNdi pp)Ln(μ-η1:η2-
O2CCH2C6H4NMe2-o)(μ-η1:η1-O2CCH2C6H4NMe2-o)]2 (Ln = Y (4b), Lu
(4c)). The reaction of 3b,c,e with PhNCO produced LLu[OC(CH2C6H4NMe2-
o)NPh]2(thf) (L = NCNdipp, Ln = Y (5b), Lu (5c); L = NCNdipp′, Ln = Lu (5e)).
i
Protonolysis of 3a,b by 2,6-diisopropylaniline formed straightforwardly the μ2-imido complexes [(NCNdipp)Ln(μ-NC6H4 Pr2-
2,6)]2 (Ln = Sc (6a), Lu (6c)). Reaction of 3e with S8 afforded the sulfur insertion products (NCNdipp′)Lu(CH2C6H4NMe2-
o)(SCH2C6H4NMe2-o)(thf) (7e) and (NCNdipp′)Lu(SCH2C6H4NMe2-o)2(thf)2 (7f) in high yields, respectively, depending on
the stoichiometric ratio. All of these complexes were fully characterized by elemental analysis, NMR spectroscopy, and X-ray
structural determinations.
developing with these ligands.4,6,7 Recent pioneering works
reported by Hessen and Hou showed that neutral mono-
(amidinate) rare-earth-metal bis(alkyl)/bis(aminobenzyl) com-
INTRODUCTION
■
Rare-earth-metal dialkyl complexes have attracted considerable
attention, due to their great potential as catalysts in olefin
transformations such as hydrosilylation,1 hydroamination,2 and
plexes are excellent precatalysts for the polymerization of
olefins.8 However, the reaction chemistry of rare-earth-metal
dibenzyl complexes possessing these ligands toward some small
molecules is still relatively undeveloped.7e,9
polymerization.3 In general, rare-earth-metal dialkyl complexes
have been synthesized by the reaction of the corresponding
tris(alkyl) complexes with neutral ligands. The use of classic salt
metathesis protocols for the synthesis of such complexes
remains a significant challenge due to the intrinsic tendency
toward the formation of ate complexes and facile ligand
redistribution.4 One way to avoid these difficulties is the
introduction of a chelating substituent on the alkyl or a bulky
coligand capable of stabilizing these complexes by the steric
saturation of the coordination sphere around the metal ions. So
far, rare-earth-metal alkyl species have been overwhelmingly
stabilized by the cyclopentadienyl group and its derivatives as
the ancillary ligands.3a,5 Thus, significant efforts have focused
on development of coligands as alternatives to cyclopentadienyl
ligands and new functionalized alkyls. Among them, the non-
Cp ligands with N, O, and P heteroatoms such as amidinate
ligands have received particular attention because of their
strong metal−ligand bonds and exceptional and tunable steric
and electronic features, and a broad new chemistry is
On the other hand, o-aminobenzyl is among the most
important alkyl ligands and is widely used to improve stability
and/or create new reactions of transition-metal complexes.10,11
Recently, rare-earth-metal complexes bearing o-aminobenzyl
ligands have proven to be attractive precursors for the
preparation of other organolanthanide derivatives.7e,12 In
order to better understand the nature of the structures and
reactivities of this class of complexes and expand their synthetic
utility in organolanthanide chemistry, the direct synthesis of o-
aminobenzyl rare-earth-metal complexes from rare-earth-metal
trichloride, with the possibility of varying the ancillary ligands,
should be very helpful.
Received: August 6, 2013
Published: December 2, 2013
© 2013 American Chemical Society
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Scheme 1. Syntheses of Lithium Amidinates and Solvent Effects
RESULTS AND DISCUSSION
■
In this paper, we describe a “one pot” synthesis of rare-earth-
metal bis(aminobenzyl) complexes bearing a bulky benzamidi-
nate ligand from the sequential reaction of anhydrous LnCl3
with lithium amidinate and 2 equiv of (aminobenzyl)lithium
and their reaction behavior toward some small molecules such
as carbon dioxide, isocyanate, amine, and sulfur. In addition,
during the syntheses of lithium amidinate intermediates, three
different bonding modes of C-phenyl-substituted amidinate to
the lithium ion are observed.
Figure 1. Molecular structure of complexes 1b (left) and 1c (right)
with thermal ellipsoids at 30% probability. All of the hydrogen atoms
are omitted for clarity. Selected bond lengths (Å) and angles (deg) are
as follows. 1b: Li1−N1 1.98(1), Li1−O1 1.96(1); N1−Li1−N1A
68.9(3), N1−Li1−O1 123.1(2), N1−Li1−O1A 135.8(2), O1−Li1−
O1A 80.2(5). 1c: Li1−N1 2.00(1), Li1−O1 2.01(1), Li1−O2 2.00(1),
Li1−O3 2.03(1); N1−Li1−O1 120.8(3), N1−Li1−O2 128.4(3), N1−
Li1−O3 116.6(2), O1−Li1−O2 82.2(2).
Syntheses and Characterization of Lithium Amidi-
nates. The reaction of C(NC6H4 Pr2-2,6)2 with 1 equiv of PhLi
i
in THF at room temperature afforded the corresponding
i
lithium amidinate [PhC(NC6H4 Pr2-2,6)2)]Li(THF) (1a)
quantitatively (Scheme 1). 1a could be transformed into
three new solvated complexes depending on the crystallization
conditions. Recrystallization of 1a in DME allowed the isolation
i
of the adduct [PhC(NC6H4 Pr2-2,6)2]Li(DME) (1b), while
recrystallization of 1a in mixed DME/THF gave [PhC-
i
(NC6H4 Pr2-2,6)2]Li(DME)(THF) (1c).
Furthermore, recrystallization of 1a in toluene formed
[PhC(NC6H4 Pr2-2,6)2]Li[μ-η4:η4-PhC(NC6H4 Pr2-2,6)2]Li-
(THF) (1d).
i
i
Compounds 1a−d were well characterized by NMR spectra.
The signals of isopropyl groups in 1a appeared at δ 3.58 (CH),
1.08 (Me), and 0.73 ppm (Me). The NMR spectra of 1b
showed that replacement of coordinated THF by DME led to
the migration of isopropyl absorptions from high to low
magnetic field at 3.75 (CH), 1.29 (Me), and 1.15 ppm (Me). It
was unexpected that the two 2,6-diisopropylphenyl groups of
1c would be equivalent, and absorptions appeared at 3.74
(CH), 1.28 (Me), and 1.13 ppm (Me) attributable to isopropyl,
indicating that there may be a fast exchange between bonding
N and nonbonding N. In the 1H NMR spectrum of 1d, the CH
proton on the coordinated aryl ring appears as a multiplet at
3.23 ppm, while the corresponding resonance of the free aryl
groups exists at 3.72 ppm as a multiplet peak.
Figure 2. Molecular structure of complex 1d with thermal ellipsoids at
30% probability. All of the hydrogen atoms are omitted for clarity.
Selected bond lengths (Å) and angles (deg): Li1−N1 2.01(1), Li1−
N2 2.05(1), Li1−N3 2.00(1), Li2−N4 1.94(1), Li2−O1 1.84(1); N1−
Li1−N2 68.0(2), O1−Li2−N4 127.7(4).
is normally η2-bonded to the metal through two N atoms.
Surprisingly, the amidinate anion in 1c coordinates to the
lithium ion in a η1 fashion, although the negative charge is
delocalized to form two equivalent C−N bonds. The mismatch
between negative charge distribution and bonding mode of the
amidinate ligand is somewhat puzzling; a possible explanation
would be a rapid intra- or intermolecular transmetalation
The structures of complexes 1b−d have been further
confirmed by X-ray single-crystal diffraction analysis, wherein
three different bonding modes of PhC(NC6H4iPr2-2,6)2 anion
to Li+ ion are observed (Figures 1 and 2). In 1b the amidinate
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leading to the bonding equilibrium between two N atoms. As
shown in Figure 2, 1d is a THF-solvated dinuclear structure, in
which one bidentate polyarylated amidinate ligand chelates one
metal, while another acts as both a bridging and side-on
chelating group to connect two metals in an unprecedented μ-
η4:η4 bonding mode. The two Li atoms are located in two
different coordinate environments. Li1 is coordinated by one
chelating η2-N,N unit and one η4-azadiene from another
amidinate to form a distorted-tetragonal-bipyramidal geometry,
while Li2 is coordinated by one N atom, one η3-aryl group, and
one THF oxygen atom to form a distorted-tetrahedral
geometry. The bond parameters indicate that the π electrons
of CN double bonds are delocalized over the amidinate
skeleton. This type of bonding mode of C-aryl of amidinate to
the metal center observed is a rare example, although amidinate
complexes have been studied extensively.7a,8b,13 The results
To avoid the formation of ligand distribution or salt-type
byproducts, the dilute THF solution of 1a generated in situ was
dropped into the THF slush of LnCl3 slowly. Then THF
solvent was removed, the residue was extracted with toluene (3
× 20 mL), the extract was concentrated to about 5 mL, and
recrystallization was carried out to give pale yellow crystals.
All complexes have been characterized by NMR spectrosco-
py, elemental analysis, and X-ray structural analysis. The results
indicate that all three complexes are solvated monomeric
structures. In contrast, the rare-earth dichloride complexes
bearing Cp or substituted Cp ligands were obtained as dimers
with two Cl bridges in many cases.14 The Y−Cl bond (2.579 Å)
is significantly shorter than Y−(μ-Cl) (2.614−2.776 Å),15 but it
is consistent with a bond found from yttrium to a terminal
chlorine atom (2.58 Å).16 The number of coordinated THF
molecules in the solid-state structure of these complexes
increases with an increase of the metal ionic radius (Figure 3).
However, attempts to synthesize the analogues of the larger
rare earth metals such as La, Nd, and Sm were unsuccessful;
only oily complex products were obtained.
Synthesis and Characterization of Mono(amidinate)
Rare-Earth-Metal Bis(aminobenzyl) Complexes. Reactions
of o-Me2NC6H4CH2Li with the in situ generated
LLnCl2(THF)n at room temperature yielded the corresponding
bis(o-aminobenzyl) complexes LLn(CH2C6H4NMe2-o)2 (L =
NCNdipp, Ln = Sc (3a, 92%), Y (3b, 88%), Lu (3c, 90%); L =
NCNdipp′, Ln = Sc (3d, 84%), Lu (3e, 92%)) (Scheme 3 and
Figure 4). However, treatment of 1a with SmCl3 (or GdCl3)
followed by reaction with Me2NC6H4CH2Li under the same
conditions gave an oily mixture.
i
indicate that the bonding mode of PhC(NC6H4 Pr2-2,6)2 to
metal in the lithium series varies as a function of the coligand,
which represents a good example that the change of the
bonding mode of aryl-substituted amidinate to metal from
monodentate, through bidentate, to multidentate can be finely
tuned simply by changing the nature of the coordinating
solvent.
Synthesis and Characterization of Mono(amidinate)
Rare-Earth-Metal Dichloride Complexes. The reactions of
LnCl3 with 1 in THF afforded neutral amidinate rare-earth-
metal dichlorides (NCNdipp)LnCl2(THF)n (n = 2, Ln = Sc (2a,
93%); n = 3, Ln = Y (2b, 94%), Lu (2c, 96%)) in excellent
yields (Scheme 2).
Complexes 3 are stable under an N2 atmosphere even at 80
°C. They are sparingly soluble in hexane but readily dissolve in
THF and aromatic solvents. It is noteworthy that the 1H NMR
spectrum of 3a shows broad signals in the ranges 4.56−3.16
and 1.80−0 ppm for the isopropyl group at ambient
temperature. However, the signal at 3.87 ppm attributable to
the methine proton becomes sharp when the measurement
temperature is increased to 70 °C, and the corresponding
methyl protons split into two groups of doublet signals at 1.36
and 0.94 ppm, respectively. Resonances for the alkyls of the
aminobenzyl groups appear at 2.44 (−NMe2) and 1.90 ppm
Scheme 2. Syntheses of Monoamidinate Rare-Earth-Metal
Dichloride Complexes
Figure 3. Molecular structure of complexes 2 with thermal ellipsoids at 30% probability. All of the hydrogen atoms are omitted for clarity. Selected
bond lengths (Å) and angles (deg) are as follows. Sc (2a): Sc(1)−N(1) 2.171(3), Sc(1)−N(2) 2.172(3), Sc(1)−O(1) 2.193(3), Sc(1)−O(2)
2.193(3), Sc(1)−Cl(1) 2.430(2), Sc(1)−Cl(2) 2.427(2); N(1)−Sc(1)−N(2) 61.9(1), Cl(1)−Sc(1)−Cl(2) 164.5(1), O(1)−Sc(1)−O(2) 103.7(1).
Y (2b): Y(1)−N(1) 2.384(3), Y(1)−O(1) 2.439(3), Y(1)−O(2) 2.506(3), Y(1)−Cl(1) 2.579(1); N(1)−Y(1)−N(1A) 55.4(1), Cl(1)−Y(1)−
Cl(1A) 164.8(1), O(1)−Y(1)−O(1A) 143.7(1), O(1)−Y(1)−O(2) 71.8(1). Lu (2c): Lu(1)−N(1) 2.345(3), Lu(1)−O(1) 2.398(3), Lu(1)−O(2)
2.474(4), Lu(1)−Cl(1) 2.525(1); N(1)−Lu(1)−N(1A) 56.5(2), Cl(1)−Lu(1)−Cl(1A) 165.2(1), O(1)−Lu(1)−O(1A) 143.7(1), O(1)−Lu(1)−
O(2) 71.8(1).
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Scheme 3. Syntheses of Mono(amidinate) Rare-Earth-Metal
Bis(aminobenzyl) Complexes
Table 1. Selected Bond Lengths and Angles for 3a,c−e
3a (Sc)
3c (Lu)
3d (Sc)
3e (Lu)
Bond Lengths (Å)
Ln−C1
Ln−C10
Ln−N1
Ln−N2
Ln−N3
Ln−N4
2.287(3)
2.415(7)
2.378(7)
2.346(5)
2.352(5)
2.548(6)
2.527(6)
2.287(6)
2.275(6)
2.198(5)
2.209(5)
2.432(6)
2.521(6)
2.414(5)
2.413(6)
2.308(4)
2.344(5)
2.502(6)
2.581(4)
2.282(3)
2.227(2)
2.207(3)
2.483(3)
2.492(3)
Bond Angles (deg)
C1−Ln−C10
N1−Ln−N2
N3−Ln−N4
C1−Ln−N3
C10−Ln−N4
153.3(1)
129.5(3)
57.8(2)
122.9(2)
67.6(2)
68.4(3)
156.4(2)
61.2(2)
96.4(2)
72.4(2)
69.4(2)
154.3(2)
57.9(1)
98.5(2)
70.1(2)
67.9(2)
60.4(1)
103.5(1)
70.4(1)
70.7(1)
(CH2). Complexes 3b,c give well-resolved NMR spectra in
C6D6 at ambient temperature. Methine and methyl protons of
the isopropyl group split into two sets of broad signals and
three groups of broad signals, indicating a loss of symmetry in
these two complexes. Methine protons exhibit a multiplet signal
at 3.81 ppm for complex 3d and 3.73 ppm for complex 3e.
Methyl protons of isopropyl groups show two groups of
doublets at 1.38 and 1.25 ppm for 3d and 1.36 and 1.26 ppm
for 3e. The two CH2C6H4NMe2-o groups exhibit one NMe2
signal and one CH2 signal at δ 2.39 and 2.02 ppm for 3d and at
2.37 and 1.83 ppm for 3e, respectively.
The structures of complexes 3 were determined by single-
crystal X-ray structural analysis. The rare-earth-metal ion in
each of complexes 3 is six-coordinated by two nitrogen atoms
from the amidinate ligand, two carbon atoms, and two amino
nitrogen atoms, forming a distorted-octahedral geometry.
Selected bond distances and angles are summarized in Table
1. The average distance of Ln−Nalkyl bonds in complex 3c
(2.538(6) Å) is in the normal range of Ln−N donating
bonds.17 It is noteworthy that two Ln−C bonds are almost the
same in complex 3a; however, in complex 3c there is a
difference of 0.037 Å since the greater size of Lu allows one of
the phenyl rings of the aminobenzyl moieties to approach more
closely to the metal ion center. This feature was also observed
in complex 3b.8e
(Ln = Y (4b), Lu (4c)) (Scheme 4). The X-ray crystallographic
studies indicate that 4b,c are isostructural (Figure 5, right).18 It
is interesting that the coordination modes of carboxyl groups in
complexes 4 depend on the size of the metals. In 4a all of the
newly formed carboxyl ligands bridge two (NCNdipp)Ln
fragments through an μ-η1:η1 bonding mode (Figure 5, left),
while in 4b,c the carboxyl bridges bear two different bonding
modes: μ-η1:η1 and μ-η1:η2. The C−O bond distances in 4c,
ranging from 1.228(6) to 1.280(6) Å, are between the typical
values for a C−O single bond and a CO double bond,
indicating that the negative charge is delocalized on the O
CO unit.19 The Lu−O bond distances are in the previously
reported range of 2.210(9)−2.566(2) Å.20
Reactions of Bis(aminobenzyl) Complexes with
PhNCO. To get more information about the reactivities of
these dialkyl complexes, the reactions of complexes 3b,c with
PhNCO were examined as well. Treatment of 3b,c with 2 equiv
of PhNCO in THF at −15 °C gave the insertion products
(NCNdipp)Ln[OC(CH2C6H4NMe2-o)NPh]2(THF) (Ln = Y
(5b), Lu (5c)) in moderate yields (Scheme 5). Notably, when
the reaction was carried out at room temperature, the
cyclotrimerization byproduct (PhNCO)3 was obtained. In the
1H NMR spectrum, signals for the methylene of aminobenzyl
groups partially overlap with the methine of the isopropyl
group at around 3.85 (5b) and 3.84 (5c) ppm, but signals for
N-methyls clearly appeared at 2.45 (5b) and 2.46 (5c) ppm.
Reactions of Bis(aminobenzyl) Complexes with CO2.
To explore the reactivity of these dialkyl complexes, the
reactions of complexes 3a−c with CO2 were carried out.
Introduction of CO2 into a toluene solution of 3a−c led to a
color change from yellow to colorless immediately, forming the
expected Ln−C bond insertion products [(NCNdipp)Sc(μ-
η1:η1-O2CCH2C6H4NMe2-o)2]2 (4a) and [(NCNdipp)Ln(μ-
η1:η2-O2CCH2C6H4NMe2-o)(μ-η1:η1-O2CCH2C6H4NMe2-o)]2
Figure 4. Molecular structure of complexes 3 (R = Ph, Ln = Sc (3a), Lu (3c); R = CH2C6H4NMe2-o, Ln = Sc (3d), Lu (3e)) with thermal ellipsoids
at 30% probability. All of the hydrogen atoms are omitted for clarity.
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Scheme 4. Reactions of Rare-Earth-Metal Bis(aminobenzyl)
Complexes with CO2
Scheme 5. Reactions of 3 with PhNCO
Complexes 5b,c are mononuclear (Figure 6). The metal ion
is coordinated by one THF molecule, one η2-amidinate ligand,
and two η2-amido ligands. The average Lu−Namidinate bond
distance of 2.318(5) Å is in the normal bonding range. The
average Lu−O and Lu−N bond lengths involving the amido
moiety are 2.262(4) and 2.370(5) Å, respectively (Table 2).
Taking account of the difference between metal ionic radii, they
compare well with the corresponding values in (C5H4Me)2Ho-
[OC(nBu)NPh].21
Figure 6. Molecular structures of complexes 5b (left) and 5c (right)
with thermal ellipsoids at 30% probability. 2,6-Diisopropylphenyls of
amidinate ligands and all of the hydrogen atoms are omitted for clarity.
In contrast to the case for 3c, only the insertion product
(NCNdipp′)Lu[OC(CH2C6H4NMe2-o)NPh]2(THF) (5e) was
Figure 5. Molecular structures of complexes 4a (left) and 4c (right) with thermal ellipsoids at 30% probability. 2,6-Diisopropylphenyls of amidinate
ligands and all of the hydrogen atoms are omitted for clarity. Selected bond lengths (Å) and angles (deg) are as follows. 4a (Sc): Sc(1)−O(1)
2.097(2), Sc(1)−O(2) 2.123(2), Sc(1)−N(1) 2.195(2), C(18)−O(1) 1.260(3), C(18A)−O(2) 1.256(3); N(1)−Sc(1)−N(1A) 60.7(1), O(1A)−
Sc(1)−O(1) 158.0(1), O(1A)−Sc(1)−O(2) 85.0(1), O(1)−Sc(1)−O(2) 83.8(1), O(1A)−Sc(1)−O(2A) 83.8(1), O(1)−Sc(1)−O(2A) 85.0(1),
O(2)−Sc(1)−O(2A) 118.1(1), O(1)−C(18)−O(2A) 123.5(2). 4c (Lu): Lu(1)−O(1) 2.498(4), Lu(1)−O(1A) 2.231(4), Lu(1)−O(2) 2.288(4),
Lu(1)−O(3) 2.249(4), Lu(1)−O(4A) 2.196(4), Lu(1A)−O(1) 2.231(4), Lu(1A)−O(4) 2.196(4), Lu(1)−N(1) 2.280(4), Lu(1)−N(2) 2.307(4),
C(32)−O(1) 1.274(6), C(32)−O(2) 1.228(6), C(42)−O(3) 1.244(6), C(42)−O(4) 1.280(6); O(1)−Lu(1)−O(1A) 83.0(1), O(1)−Lu(1)−O(2)
54.2(1), O(1)−Lu(1)−O(3) 75.6(1), O(1)−Lu(1)−O(4A) 77.4(1), O(2)−Lu(1)−O(3) 80.7(1), O(1A)−Lu(1)−O(2) 136.0(1), O(2)−Lu(1)−
O(4A) 99.7(2), O(1A)-Lu(1)−O(3) 79.1(1), O(3)−Lu(1)−O(4A) 146.1(1), O(1A)−Lu(1)−O(4A) 77.5 (1), N(1)−Lu(1)−N(2) 57.6(2),
O(1)−C(32)−O(2) 122.1(6), O(3)−C(42)−O(4) 126.4(5).
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Complexes 6 are sensitive to air and moisture and are readily
soluble in THF and aromatic solvents but sparingly soluble in
hexane. The structure of 6a was determined by single-crystal X-
ray diffraction. As shown in Figure 8, complex 6a adopts a
Table 2. Selected Bond Lengths and Angles for 5b,c,e
5b
5c
5e
Bond Lengths (Å)
Ln−O1
Ln−O2
Ln−O3
Ln−N1
Ln−N2
Ln−N3/N4
Ln−N5/N6
2.289(2)
2.330(2)
2.367(2)
2.404(2)
2.338(2)
2.413(2)
2.418(2)
2.296(4)
2.229(4)
2.345(4)
2.288(5)
2.348(5)
2.391(6)
2.350(5)
2.287(6)
2.264(6)
2.368(9)
2.355(6)
2.350(7)
2.369(9)
2.375(9)
Bond Angles (deg)
N1−Ln−N2
55.8(1)
56.2(1)
55.2(1)
118.3(3)
116.3(2)
58.0(2)
56.4(5)
55.5(4)
57.2(5)
O1−Ln−N3/N4
O2−Ln−N5/N6
O1−C32−N3
O2−C48−N5
O1−C35−N4
O2−C51−N6
57.6(2)
57.5(2)
118.7(7)
115.5(6)
Figure 8. Molecular structure of complex 6a with thermal ellipsoids at
30% probability. 2,6-Diisopropylphenyls of amidinate ligand and all of
the hydrogen atoms are omitted for clarity. Selected bond lengths (Å)
and angles (deg): Sc(1)−N(1) 2.197(2), Sc(1)−N(2) 2.222(2),
Sc(1)−N(3) 2.017(2), Sc(1)−N(3A) 2.010(2); N(1)−Sc(1)−N(2)
61.2(1), N(1)−Sc(1)−N(3) 137.4(1), N(1)−Sc(1)−N(3A) 118.1(1),
N(2)−Sc(1)−N(3) 121.7(1), N(2)−Sc(1)−N(3A) 140.9(1), N(3)−
Sc(1)−N(3A) 86.2(1), Sc(1)−N(3)−Sc(1A) 93.8(1), N(1)−C(1)−
N(2) 114.2(2).
114.6(10)
115.6(9)
obtained when 3e reacted with 2 equiv of PhNCO in THF at
room temperature (Scheme 5), indicating that the greater steric
crowding of 3e in comparison with 3c prevents PhNCO from
cyclotrimerization. As shown in Figure 7, complex 5e has a
Sc2N2 quadrilateral core structure via μ-imido bridges. The Sc−
Nimido bond lengths ranging from 2.010(2) to 2.017(2) Å are
consistent with those in the imido−scandium complex
{[C5H4(CH2)2NMe2]Sc[μ-NC(Ph)C6H10]}2.22 The Sc−
Namidinate bond lengths are in the range 2.197(2)−2.222(2) Å,
which are quite comparable with the corresponding values of
3a.
Reactions of Bis(aminobenzyl) Complex 3e with S8.
Reaction of complex 3e with 1/8 equiv of S8 afforded the single-
i
insertion product [o-Me2NC6H4CH2C(NC6H4 Pr2-2,6)2]Lu-
(CH2C6H4NMe2-o)(SCH2C6H4NMe2-o)(THF) (7e) in high
Figure 7. Molecular structure of complex 5e with thermal ellipsoids at
30% probability. 2,6-Diisopropylphenyls of amidinate ligand and all of
the hydrogen atoms are omitted for clarity.
yield.23 The double-insertion product [o-Me2NC6H4CH2C-
i
(NC6H4 Pr2-2,6)2]Lu(SCH2C6H4N-Me2-o)2(THF)2 (7f) was
1
obtained in good yield when complex 3e was treated with /4
conformation similar to that of complexes 5b,c. The average
Lu−Namidinate and Lu−O bond distances are 2.352(6) and
2.276(6) Å, respectively. All of the bond parameters involving
the metal are consistent with the corresponding values in
complex 5c.
equiv of S8 (Scheme 7). In previous studies carried out by us,
on the sulfur insertion into the Ln−C bond of alkyl and benzyl
complexes, the results obtained showed that the resulting
thiolate ligands were easily oxidized by S8 at room temperature,
forming sulfide and disulfide complexes. However, no metal
sulfide byproduct was obtained in the present cases.
Reactions of Bis(aminobenzyl) Complexes with 2,6-
Diisopropylaniline. Significantly, treatment of complexes 3a,c
with 1 equiv of 2,6-diisopropylaniline in toluene at 120 °C gave
the corresponding imido lanthanide complexes [(NCNdipp)Ln-
It is clear that the presence of the amino group at the ortho
position of the benzene ring improves the chemoselectivity of
the reaction of lanthanide benzyls with elemental sulfur.23
Single-crystal X-ray diffraction analysis determined the
coordination number of complexes 7 to be 6. The metal in
7e is surrounded by one amidinate ligand, one aminobenzyl,
one thiolate and a THF molecule, to form a distorted-
octahedral geometry. Interestingly, in contrast to 3, in 7e,f the
NMe2 group of the resulting SCH2C6H4NMe2-o ligand is free;
instead, the vacated coordination sites are occupied by THF
molecules (Figure 9). This difference may be attributed to the
larger ring strain of the six-membered ring in comparison with
that of the five-membered ring, preventing the NMe2 group
from forming the intramolecular chelating coordination
competitively. The newly formed Lu−S bond distance is
2.641(1) Å, which is remarkably shorter than the average Er−S
distance of 2.732(2) Å found in (C5H5)Er[SC6H4NC-
i
(μ-NC6H4 Pr2-2,6)]2 (Ln = Sc (6a), Lu (6c)) (Scheme 6).
Scheme 6. Reactions of Bis(aminobenzyl) Complexes 3 with
2,6-Diisopropylaniline
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bis(aminobenzyl) complexes with CO2 produces the corre-
sponding lanthanide carboxylate complexes. Furthermore,
ligand and temperature effects were observed in the reactions
of bis(o-aminobenzyl) complexes with PhNCO. The reactions
of bis(o-aminobenzyl) complexes with 2,6-diisopropylaniline
offer a straightforward route to μ2-imido lanthanide complexes
which are potential precursors for the synthesis of other
organolanthanide derivatives.
Scheme 7. Reactions of 3e with S8
EXPERIMENTAL SECTION
■
General Procedures and Materials. All manipulations were
performed with rigorous exclusion of air and water, using Schlenk
techniques or an Mbraun glovebox (Unilab Mbraun; <1 ppm of O2, <1
ppm of H2O). Toluene, THF, and hexane were distilled from sodium
strip/benzophenone ketyl, degassed, dried over fresh Na chips, and
stored in the glovebox. Bis(2,6-diisopropylphenyl)carbodiimide was
obtained from Tokyo Chemical Industry Co., Ltd., and used without
purification. CH3C6H4NMe2-o, nBuLi (1.6 mol/L in hexane), and PhLi
(2.0 mol/Lin dibutyl ether) were purchased from Acros and used
without purification. 2,6-Diisopropylaniline was purchased from Alfa
Aesar and dried with CaH2. C6D6 and THF-d8 were obtained from
Cambridge Isotope and dried with sodium chips. Highly pure CO2
(99.99%) was purchased from Pujiang Gas and dried by passing
through activated 4 Å molecular sieves. Phenyl isocyanate was
obtained from Alfa Aesar and dried with P2O5. LnCl3 complexes
(Ln = Sc, Y, Lu, etc.) were prepared according to literature
procedures.26 1H NMR and 13C NMR spectra were recorded on a
JEOL ECA-400 NMR spectrometer (FT, 400 MHz for 1H; 100 MHz
for 13C) in C6D6 or THF-d8 at room temperature.
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]Li(THF) (1a). A 0.5 mL
portion of PhLi/dibutyl ether solution (2 M, 1 mmol) was added
slowly to a stirred solution of bis(2,6-diisopropylphenyl)carbodiimide
(0.363 g, 1 mmol) in THF (10 mL). Complex 1a was obtained
quantitatively after the reaction mixture was stirred for 2 h at ambient
temperature. 1H NMR (400 MHz, THF-d8, room temperature): δ 6.73
(m, 9H, Ar), 6.59 (t, J = 7.6 Hz, 2H, Ar), 3.58 (m, 4H, THF), 3.46 (m,
4H, −CHMe2), 1.74 (m, 4H, THF), 1.04 (d, J = 6.8 Hz, 12H,
−CHMe2), 0.73 (d, J = 6.8 Hz, 12H, −CHMe2). 13C NMR (100 MHz,
THF-d8, room temperature): δ 167.4 (s, NCN), 148.9 (s, Ar), 141.0
(s, Ar), 137.0 (s, Ar), 131.1 (s, Ar), 126.8 (s, Ar), 126.7 (s, Ar), 122.8
(s, Ar), 120.4 (s, Ar), 68.0 (s, THF), 28.3 (s, −CHMe2), 26.1 (s,
THF), 25.1 (s, −CHMe2), 23.0 (s, −CHMe2).
Figure 9. Molecular structures of complexes 7e,f with thermal
ellipsoids at 30% probability. 2,6-Diisopropylphenyls of amidinate
ligands and all of the hydrogen atoms are omitted for clarity. Selected
bond lengths (Å) and angles (deg) are as follows. 7e (Lu): Lu(1)−
N(1) 2.342(3), Lu(1)−N(2) 2.308(3), Lu(1)−N(4) 2.542(3),
Lu(1)−C(1) 2.393(4), Lu(1)−S(1) 2.641(1), Lu(1)−O(1)
2.321(2), S(1)−C(10) 1.813(4); N(1)−Lu(1)−N(2) 58.0(1),
C(1)−Lu(1)−N(4) 70.1(1), C(1)−Lu(1)−S(1) 151.40(9), N(4)−
Lu(1)−S(1) 93.70(7). 7f (Lu): Lu(1)−N(1) 2.320(6), Lu(1)−N(2)
2.305(5), Lu(1)−S(1) 2.634(2), Lu(1)−S(2) 2.629(2), Lu(1)−O(1)
2.386(5), Lu(1)−O(2) 2.332(5), S(1)−C(1) 1.75(1), S(1)−C(10)
1.834(8); N(1)−Lu(1)−N(2) 57.8(2), S(1)−Lu(1)−S(2) 146.67(8).
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]Li(DME) (1b). A DME
solution of complex 1a was concentrated under vacuum to a 2 mL
saturated solution, and on crystallization at −35 °C, 0.510 g (95%) of
colorless crystals of 1b was obtained. 1H NMR (400 MHz, C6D6, room
temperature): δ 7.20−7.12 (m, 6H, Ar), 7.03 (t, J = 7.6 Hz, 2H, Ar),
6.82 (t, J = 7.6 Hz, 2H, Ar), 6.72 (t, J = 7.0 Hz, 1H, Ar), 3.75 (m, 4H,
−CHMe2), 3.06 (s, 6H, −CH2OMe), 2.77 (s, 4H, −CH2OMe), 1.29
(d, J = 6.8 Hz, 12H, −CHMe2), 1.15 (d, J = 6.8 Hz, 12H, −CHMe2).
13C NMR (100 MHz, C6D6, room temperature): δ 168.0 (s, NCN),
148.2 (s, Ar), 140.7 (s, Ar), 136.2 (s, Ar), 130.0 (s, Ar), 126.8 (s, Ar),
126.5 (s, Ar), 122.7 (s, Ar), 120.9 (s, Ar), 69.7 (s, −CH2OMe), 58.9 (s,
−CH2OMe), 28.1 (s, −CHMe2), 24.8 (s, −CHMe2), 22.7 (s,
−CHMe2). Anal. Calcd for C35H49N2O2Li: C, 78.32; H, 9.20; N,
5.22. Found: C, 78.70; H, 9.03; N, 5.42.
(NHiPr)2]2·THF,24 taking into account the 0.029 Å difference
between the metal ionic radii.25 The residual Lu−C distance of
2.393(4) Å is slightly shorter than the average Lu−C distance
of 2.414(6) Å observed in the precursor 3e. The solid-state
structure of complex 7f shows that Lu3+ is coordinated to
another −SCH2C6H4NMe2-o ligand instead of an aminobenzyl
group in complex 7e, and one more THF molecule fulfills the
steric saturation of the coordination around the metal ion.
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]Li(DME)(THF) (1c). Recrys-
tallization of complex 1a in a DME/THF mixed solvent gave 1c as
1
colorless crystals (0.516 g, 96%). H NMR (400 MHz, C6D6, room
temperature): δ 7.17−7.11 (m, 6H, Ar), 7.01 (t, J = 7.2 Hz, 2H, Ar),
6.81 (t, J = 7.6 Hz, 2H, Ar), 6.72 (t, J = 7.0 Hz, 1H, Ar), 3.74 (m, 4H,
−CHMe2), 3.55 (br s, 4H, THF), 3.07 (s, 6H, −CH2OMe), 2.83 (br d,
4H, −CH2OMe), 1.39 (br s, 4H, THF), 1.28 (d, J = 6.8 Hz, 12H,
−CHMe2), 1.13 (d, J = 6.8 Hz, 12H, −CHMe2). 13C NMR (100 MHz,
C6D6, room temperature): δ 167.9 (s, NCN), 148.2 (s, Ar), 140.7 (s,
Ar), 136.3 (s, Ar), 130.0 (s, Ar), 126.7 (s, Ar), 126.5 (s, Ar), 122.7 (s,
Ar), 120.9 (s, Ar), 69.9 (s, −CH2OMe), 67.7 (s, THF), 58.8 (s,
−CH2OMe), 28.1 (s, −CHMe2), 25.4 (s, THF), 24.8 (s, −CHMe2),
CONCLUSIONS
■
In summary, a series of lanthanide bis(o-aminobenzyl)
complexes with a bulky amidinate coligand have been
synthesized by treatment of LnCl3 with amidinate lithium in
THF followed by reaction with o-Me2NC6H4CH2Li. Stoichio-
metric reactions of these bis(o-aminobenzyl) complexes with
small molecules have been investigated. The reactions of
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i
22.7 (s, −CHMe2). Anal. Calcd for C39H57N2O3Li: C, 76.94; H, 9.44;
Synthesis of [PhC(NC6H4 Pr2-2,6)2]Sc(CH2C6H4NMe2-o)2 (3a).
To a THF suspension of complex 2a generated in situ was added a
THF (10 mL) solution of o-Me2NC6H4CH2Li (0.565 g, 4 mmol).
After 12 h, all volatiles were removed under vacuum, and then 60 mL
of toluene was added to the residue. The resulting brown-red
suspension was filtered, and the filtrate was concentrated under
vacuum to 5 mL. After the concentrated solution stood at ambient
temperature for 3 days, yellow crystals of 3a (1.638 g, 92%) were
N, 4.60. Found: C, 76.59; H, 9.06; N, 4.49.
i
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]Li[μ-η4:η4-PhC(NC6H4 Pr2-
2,6)2]Li(THF) (1d). Complex 1d was obtained as a yellow crystalline
product (0.468 g, 97%), similarly to the preparation of 1c described
1
above only with a slight change of mixed solvent to toluene/THF. H
NMR (400 MHz, C6D6, room temperature): δ 7.68 (m, 2H, Ar), 7.21
(d, J = 7.6 Hz, 2H, Ar), 7.12−7.07 (m, 6H, Ar), 7.00−6.90 (m, 8H,
Ar), 6.84 (t, J = 7.6 Hz, 1H, Ar), 6.77 (t, J = 7.6 Hz, 2H, Ar), 6.67 (t, J
= 7.4 Hz, 1H, Ar), 3.72 (m, 6H, −CHMe2), 3.23 (m, 2H, −CHMe2),
2.51 (br m, 4H, THF), 1.31 (d, J = 7.2 Hz, 12H, −CHMe2), 1.24 (d, J
= 6.8 Hz, 6H, −CHMe2), 1.14 (br m, 24H, −CHMe2), 0.90 (br m,
12H, −CHMe2), 0.79 (br m, 4H, THF). 13C NMR (100 MHz, C6D6,
room temperature): δ 169.2 (s, NCN), 167.9 (s, NCN), 149.6 (s, Ar),
148.4 (s, Ar), 146.7 (s, Ar), 143.4 (s, Ar), 141.4 (s, Ar), 141.3 (s, Ar),
138.8 (s, Ar), 137.1 (s, Ar), 130.4 (s, Ar), 129.0 (s, Ar), 128.7 (s, Ar),
128.5 (s, Ar), 126.7 (s, Ar), 126.5 (s, Ar), 125.2 (s, Ar), 124.2 (s, Ar),
123.3 (s, Ar), 123.1 (s, Ar), 122.7 (s, Ar), 120.9 (s, Ar), 68.1 (s, THF),
28.2 (s, −CHMe2), 28.1 (s, −CHMe2), 27.5 (s, −CHMe2), 25.6 (s,
−CHMe2), 25.4 (s, −CHMe2), 24.8 (s, −CHMe2), 24.6 (s, −CHMe2),
23.4 (s, THF), 23.2 (s, −CHMe2), 23.1 (s, −CHMe2). Anal. Calcd for
C66H86N4OLi2: C, 82.12; H, 8.98; N, 5.80. Found: C, 81.92; H, 8.46;
N, 5.56.
1
harvested. H NMR (500 MHz, C6D6, 70 °C): δ 7.19 (m, 1H, Ar),
7.07 (br s, 7H, Ar), 6.95 (m, 2H, Ar), 6.86 (m, 2H, Ar), 6.68 (m, 3H,
Ar), 6.57 (m, 2H, Ar), 6.52 (m, 2H, Ar), 3.87 (br m, 4H, −CHMe2),
2.44 (s, 12H, −NMe2), 1.90 (s, 4H, −CH2−), 1.36 (d, J = 7.0 Hz, 12H,
−CHMe2), 0.94 (d, J = 4 Hz, 12H, −CHMe2), 13C NMR (100 MHz,
C6D6, 25 °C): δ 173.8 (s, NCN), 147.5 (s, Ar), 146.9 (s, Ar), 144.7 (s,
Ar), 141.9 (s, Ar), 131.6 (s, Ar), 130.6 (s, Ar), 129.3 (s, Ar), 128.6 (s,
Ar), 128.0 (s, Ar), 126.7 (s, Ar), 125.8 (s, Ar), 124.9 (s, Ar), 124.1 (s,
Ar), 120.8 (s, Ar), 116.7 (s, Ar), 47.4 (br s, −NMe2), 47.1 (s, −CH2−),
28.1 (br s, −CHMe2), 24.6 (br s, −CHMe2), 23.4 (br s, −CHMe2).
Anal. Calcd for C49H63N4Sc: C, 78.16; H, 8.43; N, 7.44. Found: C,
78.28; H, 8.59; N, 7.12.
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]Y(CH2C6H4NMe2-o)2 (3b).
Complex 3b was obtained as a yellow crystalline product in 88% yield
(1.403 g) from the treatment of [PhC(NC6H4iPr2-2,6)2)]YCl2(THF)3
(2 mmol) with 10 mL of a THF solution of o-Me2NC6H4CH2Li
(0.565 g, 4 mmol), similarly to the preparation of 3a described above.
1H NMR (400 MHz, C6D6, 25 °C): δ 7.26 (br s, 1H, Ar), 7.07 (br s,
7H, Ar), 6.93 (m, 4H, Ar), 6.62 (m, 7H, Ar), 4.23 (br s, 2H,
−CHMe2), 3.05 (br s, 2H, −CHMe2), 2.33 (br s, 12H, −NMe2), 1.95
(br s, 4H, −CH2−), 1.62 (b m, 12H, −CHMe2), 0.93 (br s, 6H,
−CHMe2), 0.11 (br s, 6H, −CHMe2). 13C NMR (100 MHz, C6D6, 25
°C): δ 172.8 (s, NCN), 144.5 (s, Ar), 144.0 (s, Ar), 142.1 (s, Ar),
141.2 (s, Ar),133.9 (s, Ar), 131.6 (s, Ar), 130.6 (s, Ar), 128.9 (s, Ar),
128.7 (s, Ar), 128.3 (s, Ar), 127.8 (s, Ar), 127.6 (s, Ar), 126.7 (s, Ar),
124.6 (s, Ar), 124.4 (s, Ar), 123.4 (s, Ar), 120.1 (s, Ar), 118.5 (s, Ar),
47.1 (d, JY−C = 15 Hz, −CH2−), 45.4 (br s, −NMe2), 29.8 (br s,
−CHMe2), 27.8 (br s, −CHMe2), 24.8 (br s, −CHMe2), 23.0 (br s,
−CHMe2). Anal. Calcd for C49H63N4Y: C, 73.85; H, 7.97; N, 7.03.
Found: C, 73.57; H, 8.13; N, 7.18.
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]ScCl2(THF)2 (2a). A 0.5 mL
portion of an ether solution (2 M, 1 mmol) of PhLi/dibutyl was added
slowly to a stirred solution of bis(2,6-diisopropylphenyl)carbodiimide
(0.362 g, 1 mmol) in THF (15 mL). After 2 h, the reaction mixture
was added slowly via glass pipet to a THF (20 mL) suspension of
ScCl3 (0.151 g, 1 mmol). After 8 h, all volatiles were removed under
vacuum, and then 60 mL of toluene was added to the residue. The
resulting colorless suspension was filtered, the filtrate was concentrated
under vacuum to 5 mL, and colorless crystals of 2a (0.651 g, 93%)
were harvested after the solution stood at −35 °C for 5 days. 1H NMR
(400 MHz, C6D6, 25 °C): δ 7.22 (m, 2H, Ar), 7.09−7.02 (m, 6H, Ar),
6.71 (m, 3H, Ar), 4.10 (m, 4H, −CHMe2), 3.56 (br m, 8H, THF),
1.45 (m, 20H, THF and −CHMe2), 0.98 (d, J = 7.2 Hz, 12H,
−CHMe2). 13C NMR (100 MHz, C6D6, room temperature): δ 173.0
(s, NCN), 147.4 (s, Ar), 143.5 (s, Ar), 142.7 (s, Ar), 131.0 (s, Ar),
129.4 (s, Ar), 127.0 (s, Ar), 125.0 (s, Ar), 123.9 (s, Ar), 67.7 (s, THF),
27.8 (s, −CHMe2), 25.8 (s, −CHMe2), 25.6 (s, THF), 23.7 (s,
−CHMe2). Anal. Calcd for C39H55N2O2Cl2Sc: C, 66.94; H, 7.92; N,
4.00. Found: C, 65.79; H, 7.73; N, 3.91.
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]Lu(CH2C6H4NMe2-o)2 (3c).
Complex 3c was obtained as a colorless crystalline product (1.589 g,
90%), similarly to the preparation of 3a described above. H NMR
1
(400 MHz, C6D6, 25 °C): δ 7.28 (br s, 1H, Ar), 7.09 (br s, 7H, Ar),
6.94 (m, 4H, Ar), 6.58 (m, 7H, Ar), 4.42 (br s, 2H, −CHMe2), 3.13
(br s, 2H, −CHMe2), 2.51 (br s, 6H, −NMe2), 2.23 (br s, 6H,
−NMe2), 1.98 (br s, 4H, −CH2−), 1.60 (b m, 12H, −CHMe2), 0.97
(br s, 6H, −CHMe2), 0.13 (br s, 6H, −CHMe2). 13C NMR (100 MHz,
C6D6, 25 °C): δ 172.9 (s, NCN), 144.8 (s, Ar), 144.7 (s, Ar), 143.6 (s,
Ar), 141.6 (br s, Ar), 131.6 (s, Ar), 131.0 (s, Ar), 129.1 (s, Ar), 128.9
(s, Ar), 126.7 (s, Ar), 126.5 (s, Ar), 124.8 (br s, Ar), 124.7 (s, Ar),
123.3 (br s, Ar), 120.5 (s, Ar), 117.7 (s, Ar), 51.8 (s, −CH2−), 47.2 (br
s, −NMe2), 45.0 (br s, −NMe2), 29.2 (br s, −CHMe2), 27.5 (br s,
−CHMe2), 24. Seven (br s, −CHMe2), 23.6 (br s, −CHMe2), 23.2 (br
s, −CHMe2), 22.8 (br s, −CHMe2). Anal. Calcd for C49H63N4Lu: C,
66.65; H, 7.19; N, 6.34. Found: C, 66.39; H, 7.32; N, 6.22.
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]YCl2(THF)3 (2b). Complex
2b was obtained as a colorless crystalline product (0.767 g, 94%),
1
similarly to the preparation of 2a described above. H NMR (400
MHz, THF-d8, 25 °C): δ 6.99 (d, J = 8.4 Hz, 2H, Ar), 6.92−6.88 (m,
7H, Ar), 6.71 (t, J = 7.6 Hz, 2H, Ar), 3.84 (m, 4H, −CHMe2), 3.62 (br
s, THF), 1.76 (br s, THF), 1.21 (d, J = 6.4 Hz, 12H, −CHMe2), 0.71
(d, J = 6.8 Hz, 12H, −CHMe2). 13C NMR (100 MHz, THF-d8, 25
°C): δ 172.3 (s, NCN), 146.0 (s, Ar), 142.2 (s, Ar), 132.2 (s, Ar),
131.8 (s, Ar), 128.1 (s, Ar), 125.9 (s, Ar), 123.1 (br s, Ar), 122.9 (s,
Ar), 67.3 (s, THF), 27.4 (s, −CHMe2), 25.4 (s, THF), 24.5 (s,
−CHMe2), 23.3 (s, −CHMe2). Anal. Calcd for C43H63N2O3Cl2Y: C,
63.31; H, 7.78; N, 3.43. Found: C, 63.04; H, 7.58; N, 3.54.
i
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]LuCl2(THF)3 (2c). Complex
Synthesis of [o-Me2NC6H4CH2C(NC6H4 Pr2-2,6)2]Sc-
2c was obtained as a colorless crystalline product (0.866 g, 96%),
(CH2C6H4NMe2-o)2 (3d). To a stirred THF (20 mL) solution of
bis(2,6-diisopropylphenyl)carbodiimide (1.813 g, 5 mmol) was added
slowly a THF (10 mL) solution of o-Me2NC6H4CH2Li (0.706 g, 5
mmol). After 2 h, the reaction mixture was added slowly via glass pipet
to a THF (20 mL) suspension of ScCl3 (0.757g, 5 mmol). The yellow
suspension was then stirred for 12 h, and a THF (10 mL) solution of
o-Me2NC6H4CH2Li (1.411 g, 10 mmol) was added to the resulting
mixture. All volatiles were removed under vacuum after the reaction
mixture was stirred overnight, and then 60 mL of toluene was added to
the residue. The brown-red suspension was filtered, and then the
filtrate was concentrated under reduced pressure to 5 mL. Yellow
crystals of 3d (3.402 g, 84%) were obtained after the solution stood at
ambient temperature for 5 days. 1H NMR (400 MHz, C6D6, 25 °C): δ
7.05 (m, 9H, Ar), 6.92 (m, 4H, Ar), 6.65 (m, 3H, Ar), 6.53 (m, 2H,
Ar), 4.05 (s, 2H, o-Me2NPhCH2−amidinate), 3.81 (m, 4H, −CHMe2),
1
similarly to the preparation of 2a described above. H NMR (400
MHz, C6D6, 25 °C): δ 7.32 (br d, 2H, Ar), 7.08 (br s, 7H, Ar), 6.68
(br m, 2H, Ar), 4.08 (br s, 4H, −CHMe2), 3.65 (br s, 12H, THF), 1.52
(b d, J = 5.6 Hz, 12H, −CHMe2), 1.36 (br s, 12H, THF), 1.11 (bd, J =
6.4 Hz, 12H, −CHMe2); 1H NMR (400 MHz, THF-d8, 25 °C): δ 6.96
(d, J = 8.4 Hz, 2H, Ar), 6.91−6.84 (m, 7H, Ar), 6.71 (t, J = 7.6 Hz, 2H,
Ar), 3.82 (m, 4H, −CHMe2), 3.59 (br s, 12H, THF), 1.73 (br s, 12H,
THF), 1.18 (d, J = 6.4 Hz, 12H, −CHMe2), 0.68 (d, J = 6.4 Hz, 12H,
−CHMe2). 13C NMR (100 MHz, THF-d8, 25 °C): δ 171.5 (s, NCN),
145.3 (s, Ar), 142.6 (s, Ar), 142.3 (s, Ar), 132.3 (s, Ar), 131.6 (s, Ar),
128.4 (s, Ar), 126.0 (s, Ar), 123.3 (br s, Ar), 123.2 (s, Ar), 67.4 (s,
THF), 27.3 (s, −CHMe2), 25.4 (s, THF), 24.6 (s, −CHMe2) 23.3 (s,
−CHMe2). Anal. Calcd for C43H63N2O3Cl2Lu: C, 57.27; H, 7.04; N,
3.11. Found: C, 56.98; H, 6.86; N, 3.23.
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2.39 (s, 12H, −CH2C6H4NMe2-oalkyl), 2.02 (s, 4H, −CH2C6H4NMe2-
oalkyl), 1.91 (s, 6H, o-Me2NPhCH2−amidinate), 1.38 (d, J = 6.4 Hz, 12H,
−CHMe2), 1.25 (d, J = 6.8 Hz, 12H, −CHMe2). 13C NMR (100 MHz,
C6D6, 25 °C): δ 178.7 (s, NCN), 152.3 (s, Ar), 149.3 (s, Ar), 148.0 (s,
Ar), 143.7 (s, Ar), 143.1 (s, Ar), 131.1 (s, Ar), 129.6 (s, Ar), 129.5 (s,
Ar), 126.9 (s, Ar), 125.8 (s, Ar), 125.1 (s, Ar), 124.3 (s, Ar), 121.1 (s,
Ar), 120.1 (s, Ar),117.3 (s, Ar), 47.7 (s, −CH2C6H4NMe2-oalkyl), 46.9
(s, o-Me2NPhCH2−amidinate), 44.3 (s, o-Me2NPhCH2−amidinate), 30.1 (s,
−CH2C6H4NMe2-oalkyl), 28.0 (br s, −CHMe2), 26.5 (br s, −CHMe2),
25.1 (s, −CHMe2). Anal. Calcd for C52H70N5Sc: C, 77.10; H, 8.71; N,
8.65. Found: C, 76.84; H, 8.87; N, 8.47.
−CHMe2), 22.9 (s, −CHMe2). Anal. Calcd for C102H126N8O8Y2: C,
69.22; H, 7.18; N, 6.33. Found: C, 68.96; H, 7.33; N, 6.17.
Synthesis of {[PhC(NC6 H4 i Pr2 -2,6)2 ]Lu(μ-η1 :η2 -
O2CCH2C6H4NMe2-o)(μ-η1:η1-O2CCH2C6H4NMe2-o)}2 (4c). Com-
plex 4c was obtained as a colorless crystalline product (0.368 g, 76%),
1
similarly to the preparation of 4b described above. H NMR (400
MHz, C6D6, 25 °C): δ 7.41 (br m, 4H, Ar), 7.20−6.93 (m, 24H, Ar),
6.86 (m, 4H, Ar), 6.67 (m, 4H, Ar), 6.60 (m, 2H, Ar), 3.73 (s, 16H,
−CHMe2 and −OOCCH2C6H4NMe2-o), 2.43 (s, 24H,
−OOCCH2C6H4NMe2-o), 1.22 (d, J = 6.4 Hz, 24H, −CHMe2),
1.12 (d, J = 6.8 Hz, 24H, −CHMe2). 1H NMR (400 MHz, THF-d8, 25
°C): δ 7.05−6.97 (br m, 12H, Ar), 6.89 (br d, 6H, Ar), 6.82−6.70 (br
m, 20H, Ar), 3.47−3.38 (br m, 16H, −CHMe2 and
−OOCCH2C6H4NMe2−), 2.42 (br s, 24H, −OOCCH2C6H4NMe2-
o), 0.95 (d, J = 6.8 Hz, 24H, −CHMe2), 0.87 (d, J = 6.0 Hz, 24H,
−CHMe2), 13C NMR (100 MHz, THF-d8, 25 °C): δ 184.5 (s,
−OOCCH2C6H4NMe2-o), 175.7 (s, NCN), 152.8 (s, Ar), 142.9 (s,
Ar), 142.4 (s, Ar), 132.6 (s, Ar), 130.6 (s, Ar), 130.0 (s, Ar), 129.7 (s,
Ar), 128.5 (s, Ar), 127.0 (s, Ar), 126.3 (s, Ar), 123.6 (s, Ar), 123.2 (s,
Ar), 122.6 (s, Ar), 119.2 (s, Ar), 44.8 (br s, −OOCCH2C6H4NMe2-o),
37.4 (s, −OOCCH2C6H4NMe2-o), 27.9 (s, −CHMe2), 24.8 (s,
−CHMe2), 22.4 (s, −CHMe2). Anal. Calcd for C102H126N8O8Lu2: C,
63.08; H, 6.54; N, 5.77. Found: C, 62.85; H, 6.67; N, 5.64.
i
Synthesis of [o-Me2NC6H4CH2C(NC6H4 Pr2-2,6)2]Lu-
(CH2C6H4NMe2-o)2 (3e). Complex 3e was obtained as a colorless
crystalline product (2.594 g, 92%), similarly to the preparation of 3d
1
described above. H NMR (400 MHz, C6D6, 25 °C): δ 7.20 (m, 1H,
Ar), 7.06 (m, 8H, Ar), 6.92 (m, 4H, Ar), 6.59 (m, 3H, Ar), 6.51 (m,
2H, Ar), 4.00 (s, 2H, o-Me2NPhCH2−amidinate), 3.73 (m, 4H,
−CHMe2), 2.37 (s, 12H, −CH2C6H4NMe2-oalkyl), 1.93 (s, 6H, o-
Me2NPhCH2−amidinate), 1.83 (s, 4H, −CH2C6H4NMe2-oalkyl), 1.36 (d, J
= 6.4 Hz, 12H, −CHMe2), 1.26 (d, J = 6.4 Hz, 12H, −CHMe2). 13C
NMR (100 MHz, C6D6, 25 °C): δ 178.3 (s, NCN), 152.3 (s, Ar),
146.6 (s, Ar), 145.5 (s, Ar), 143.4 (s, Ar), 143.3 (s, Ar), 130.6 (s, Ar),
130.1 (s, Ar), 129.2 (s, Ar), 126.8 (s, Ar), 126.1 (s, Ar), 124.9 (s, Ar),
124.0 (s, Ar), 123.6 (s, Ar), 120.4 (s, Ar), 119.7 (Ar), 117.5 (s, Ar),
51.6 (s, −CH2C6H4NMe2-oalkyl), 46.6 (s, −CH2C6H4NMe2-oalkyl), 44.3
(s, o-Me2NPhCH2−amidinate), 30.9 (s, o-Me2NPhCH2−amidinate), 28.2 (s,
−CHMe2), 26.1 (s, −CHMe2), 24.9 (s, −CHMe2). Anal. Calcd for
C52H70N5Lu: C, 66.43; H, 7.51; N, 7.45. Found: C, 66.19; H, 7.65; N,
7.31.
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]Y[OC(CH2C6H4NMe2-o)-
NPh]2(THF) (5b). Complex 5b was obtained as a pure colorless
powder (0.393 g, 78%, based on complex 3b) when complex 3b
(0.399 g, 0.5 mmol) was reacted with 2 equiv of PhNCO (0.108 mL, 1
mmol) at −15 °C for 20 h, and the solvent was subsequently removed
under reduced pressure. Single crystals suitable for X-ray diffraction
1
Synthesis of {[PhC(NC6 H4 i Pr2 -2,6)2 ]Sc(μ-η1 :η1 -
O2CCH2C6H4NMe2-o)2}2 (4a). A toluene (10 mL) solution of
complex 3a (0.188 g, 0.25 mmol) was placed in a tube with a Teflon
stopcock and degassed by a freeze−pump− thaw cycle. Two
atmospheres of CO2 was introduced into the tube, and a color change
from yellow to colorless was observed within 10 min. The solution was
concentrated under reduced pressure to saturation, and colorless
crystals of 4a (0.196 g, 93%) were harvested after the solution stood at
ambient temperature for 4 days. 1H NMR (400 MHz, C6D6, 25 °C): δ
7.45 (d, J = 7.6 Hz, 4H, Ar), 7.18 (t, J = 6.8 Hz, 4H, Ar), 7.07 (t, J =
7.0 Hz, 4H, Ar), 6.97−6.87 (m, 20H, Ar), 6.68−6.57 (m, 6H, Ar), 3.76
(m, 8H, −CHMe2), 3.68 (s, 8H, −OOCCH2C6H4NMe2-o), 2.41 (s,
24H, −OOCCH2C6H4NMe2-o), 1.19 (d, J = 6.0 Hz, 24H, −CHMe2),
1.08 (d, J = 6.4 Hz, 24H, −CHMe2), 13C NMR (100 MHz, C6D6, 25
°C): δ 182.4 (s, −OOCCH2C6H4NMe2-o), 176.6 (s, NCN), 152.5 (s,
Ar), 143.0 (s, Ar), 142.7 (s, Ar), 131.3 (s, Ar), 130.5 (s, Ar), 130.0 (s,
Ar), 129.9 (s, Ar), 129.1 (s, Ar), 127.1 (s, Ar), 126.7 (s, Ar), 124.4 (s,
Ar), 123.5 (s, Ar), 123.2 (s, Ar), 119.1 (s, Ar), 44.8 (br s,
−OOCCH2C6H4NMe2-o), 37.3 (s, −OOCCH2C6H4NMe2-o), 28.0
(s, −CHMe2), 25.1 (s, −CHMe2), 23.1 (s, −CHMe2). Anal. Calcd for
C102H126N8O8Sc2: C, 72.83; H, 7.55; N, 6.66. Found: C, 73.05; H,
7.75; N, 6.51.
analysis were grown from THF/hexane at −35 °C. H NMR (400
MHz, C6D6, 25 °C): δ 7.48 (d, J = 8.0 Hz, 2H, Ar), 7.22 (d, J = 8.0 Hz,
2H, Ar), 7.11−6.91 (m, 18H, Ar), 6.71 (m, 3H, Ar), 6.44 (d, J = 7.6
Hz, 4H, Ar), 3.85 (br m, 8H, −CH2C6H4NMe2-o, and −CHMe2), 3.59
(br s, 4H, THF), 2.45 (s, 12H, −CH2C6H4NMe2-o), 1.21 (br d, 16H,
THF and −CHMe2), 1.05 (d, J = 6.8 Hz, 12H, −CHMe2). 13C NMR
(100 MHz, C6D6, 25 °C): δ 182.0 (s, NCO), 173.6 (s, NCN), 153.1
(s, Ar), 147.6 (s, Ar), 144.6 (s, Ar), 142.1 (s, Ar), 133.0 (s, Ar), 132.3
(s, Ar), 131.0 (s, Ar), 130.5 (s, Ar), 128.5 (s, Ar), 128.4 (s, Ar), 126.9
(s, Ar), 126.8 (s, Ar), 124.6 (s, Ar), 123.5 (s, Ar), 122.9 (s, Ar), 122.8
(s, Ar), 119.3 (s, Ar), 69.2 (br s, THF), 44.8 (s, −CH2C6H4NMe2-o),
33.5 (s, −CH2C6H4NMe2-o), 28.1 (s, −CHMe2), 25.1 (s, −CHMe2),
25.0 (s, THF), 23.4 (s, −CHMe2). Anal. Calcd for C67H81N6O3Y: C,
72.67; H, 7.37; N, 7.59. Found: C, 72.04; H, 7.55; N, 7.37.
i
Synthesis of [PhC(NC6H4 Pr2-2,6)2]Lu[OC(CH2C6H4NMe2-o)-
NPh]2(THF) (5c). At −15 °C, a THF (8 mL) solution of PhNCO
(0.108 mL, 1 mmol) was added slowly to a stirred THF (15 mL)
solution of complex 3c (0.883 g, 1 mmol). After 20 h of workup, all of
the volatiles were removed under vacuum. Single crystals suitable for
X-ray diffraction analysis (0.776 g, 65%) were grown from THF/
1
hexane at −35 °C over 4 days. H NMR (400 MHz, C6D6, 25 °C): δ
7.48 (d, J = 7.2 Hz, 2H, Ar), 7.24 (d, J = 7.2 Hz, 2H, Ar), 7.11−6.88
(m, 18H, Ar), 6.70 (m, 3H, Ar), 6.40 (d, J = 8.0 Hz, 4H, Ar), 3.84 (br
m, 8H, −CH2C6H4NMe2-o, and −CHMe2), 3.61 (br s, 4H, THF), 2.46
(s, 12H, −CH2C6H4NMe2-o), 1.20 (br d, 18H, THF and −CHMe2),
1.04 (d, J = 6.4 Hz, 12H, −CHMe2). 13C NMR (100 MHz, C6D6, 25
°C): δ 181.5 (s, NCO), 172.9 (s, NCN), 153.1 (s, Ar), 147.4 (s, Ar),
144.7 (s, Ar), 142.4 (s, Ar), 133.2 (s, Ar), 132.2 (s, Ar), 131.1 (s, Ar),
130.7 (s, Ar), 128.6 (s, Ar), 128.3 (s, Ar), 127.0 (s, Ar), 126.8 (s, Ar),
124.9 (s, Ar), 123.6 (s, Ar), 123.5 (s, Ar), 123.0 (s, Ar), 122.8 (s, Ar),
119.3 (s, Ar), 69.9 (s, THF), 44.8 (s, −CH2C6H4NMe2-o), 33.7 (s,
−CH2C6H4NMe2-o), 27.9 (s, −CHMe2), 25.1 (s, −CHMe2), 25.0 (s,
THF), 23.6 (s, −CHMe2). Anal. Calcd for C67H81N6O3Lu: C, 67.43;
H, 6.84; N, 7.04. Found: C, 67.14; H, 6.90; N, 7.03.
Synthesis of {[PhC(NC6 H4 i Pr2 -2, 6)2 ]Y(μ-η1 :η2 -
O2CCH2C6H4NMe2-o)(μ-η1:η1-O2CCH2C6H4NMe2-o)}2 (4b). A tol-
uene (10 mL) solution of complex 3b (0.199 g, 0.25 mmol) was
placed in a tube with a Teflon stopcock and degassed by a freeze−
pump−thaw cycle. Two atmospheres of CO2 was introduced into the
tube, and a color change from yellow to colorless was observed within
5 min. The solution was concentrated under reduced pressure to 2
mL, and colorless crystals of 4b (0.172 g, 78%) were harvested after
1
the solution stood at ambient temperature for 3 days. H NMR (400
MHz, C6D6, 25 °C): δ 7.40 (b m, 4H, Ar), 7.18−7.09 (m, 7H, Ar),
7.02−6.82 (m, 21H, Ar), 6.67 (m, 4H, Ar), 6.60 (m, 2H, Ar), 3.69 (m,
16H, −OOCCH2C6H4NMe2-o and −CHMe2), 2.44 (s, 24H,
−OOCCH2C6H4NMe2-o), 1.21 (d, J = 6.8 Hz, 24H, −CHMe2),
1.13 (d, J = 6.8 Hz, 24H, −CHMe2), 13C NMR (100 MHz, C6D6, 25
°C): δ 184.6 (s, −OOCCH2C6H4NMe2-o), 176.5 (s, NCN), 153.0 (s,
Ar), 143.1 (s, Ar), 142.2 (s, Ar), 132.5 (s, Ar), 130.9 (s, Ar), 130.4 (s,
Ar), 129.6 (s, Ar), 128.6 (s, Ar), 126.6 (s, Ar), 124.0 (s, Ar), 123.6 (s,
Ar), 123.0 (s, Ar), 119.7 (s, Ar), 45.2 (br s, −OOCCH2C6H4NMe2-o),
37.8 (s, −OOCCH2C6H4NMe2-o), 28.3 (s, −CHMe2), 25.1 (s,
i
Synthesis of [o-Me2NC6H4CH2C(NC6H4 Pr2-2,6)2]Lu[OC-
(CH2C6H4NMe2-o)NPh]2(THF) (5e). At −35 °C, a THF (10 mL)
solution of PhNCO (0.22 mL, 2 mmol) was added slowly to a stirred
THF (15 mL) solution of complex 3e (0.94 g, 1 mmol). The solution
was warmed to room temperature and stirred for 12 h. The solvent
was removed under reduced pressure, leaving 5e as a colorless powder
(1.225 g, 98%, based on complex 3e). Single crystals suitable for X-ray
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Article
diffraction analysis were grown from THF/hexane mixed solvent at
−35 °C for 6 days. 1H NMR (400 MHz, C6D6, 25 °C): δ 7.76 (d, J =
7.2 Hz, 1H, Ar), 7.53 (d, J = 7.2 Hz, 2H, Ar), 7.12 (m, 7H, Ar), 7.07−
6.96 (m, 11H, Ar), 6.84 (t, J = 7.2 Hz, 2H, Ar), 6.66 (d, J = 7.6 Hz, 1H,
Ar), 6.53 (d, J = 7.6 Hz, 4H, Ar), 3.90 (m, 10H, o-
Me2NPhCH2−amidinate, −CH2C6H4NMe2-oalkyl, and −CHMe2), 2.62
(m, 4H, THF), 2.51 (s, 12H, −CH2C6H4NMe2-oalkyl), 1.91 (s, 6H, o-
Me2NPhCH2−amidinate), 1.31 (d, J = 6.4 Hz, 12H, −CHMe2), 1.23 (d, J
= 6.8 Hz, 12H, −CHMe2), 1.15 (m, 4H, THF). 13C NMR (100 MHz,
C6D6, 25 °C): δ 182.1 (s, NCO), 177.2 (s, NCN), 153.4 (s, Ar), 152.5
(s, Ar), 147.4 (s, Ar), 144.0 (s, Ar), 132.6 (s, Ar), 132.1 (s, Ar), 131.3
(s, Ar), 129.4 (s, Ar), 128.4 (s, Ar), 127.2 (s, Ar), 126.6 (s, Ar), 124.9
(s, Ar), 124.2 (s, Ar), 124.1 (s, Ar), 123.6 (s, Ar), 123.1 (s, Ar), 123.0
(s, Ar), 119.9 (s, Ar), 119.7 (s, Ar), 70.2 (s, THF), 45.1 (s,
−CH2C6H4NMe2-oalkyl), 44.3 (s, o-Me2NPhCH2−amidinate), 34.0 (s,
−CH2C6H4NMe2-oalkyl), 30.4 (s, o-Me2NPhCH2−amidinate), 28.0 (s,
−CHMe2), 26.2 (s, −CHMe2), 24.9 (s, THF), 24.5 (s, −CHMe2).
Anal. Calcd for C70H88N7O3Lu: C, 67.24; H, 7.09; N, 7.84. Found: C,
66.96; H, 7.04; N, 7.88.
−CHMe2). Anal. Calcd for C56H78N5OSLu: C, 64.41; H, 7.53; N,
6.71. Found: C, 64.29; H, 7.70; N, 6.81.
i
Synthesis of [o-Me2NC6H4CH2C(NC6H4 Pr2-2,6)2]Lu-
(SCH2C6H4NMe2-o)2(THF)2 (7f). To a stirred THF (20 mL) solution
of complex 3e (0.470 g, 0.5 mmol) was added slowly a THF (8 mL)
solution of S8 (0.032 g, 0.125 mmol). After it was stirred at room
temperature for 12 h, the solution was concentrated under vacuum to
saturation and colorless crystals of 7f (0.448 g, 78%) were obtained.
1H NMR (500 MHz, C6D6, 60 °C): δ 7.88 (s, 2H, Ar), 7.57 (s,1H,
Ar), 7.07 (t, J = 7.2 Hz, 3H, Ar), 7.02−6.83 (m, 11H, Ar), 6.59 (s, 1H,
Ar), 4.41 (s, 2H, o-Me2NPhSCH2−), 3.94 (br s, 6H, o-
Me2NPhCH2−amidinate and −CHMe2), 3.56 (br s, 4H, THF), 2.71
(br s, 12H, −CH2C6H4NMe2-oalkyl and o-Me2NPhSCH2−), 1.94 (s,
2H, −CH2C6H4NMe2-oalkyl), 1.87 (s, 6H, o-Me2NPhCH2−amidinate),
1.46 (br s, 18H, −CHMe2), 1.04 (br s, 10H, −CHMe2 and THF). 13
C
NMR (125 MHz, C6D6, 60 °C): δ 180.6 (s, NCN), 152.0 (s, Ar),
143.6 (s, Ar), 141.9 (s, Ar), 136.8 (s, Ar), 130.8 (s, Ar), 130.5 (s, Ar),
128.5 (s, Ar), 126.4 (s, Ar), 126.0 (s, Ar), 124.6 (s, Ar), 123.9 (s, Ar),
123.5 (s, Ar), 122.8 (s, Ar), 119.6 (Ar), 117.9 (s, Ar), 68.4 (s, THF),
44.6 (s, o-Me2NPhSCH2−), 43.7 (s, o-Me2NPhCH2−amidinate), 31.8 (s,
o-Me2NPhCH2−amidinate), 29.9 (s, o-Me2NPhSCH2−), 28.2 (s,
−CHMe2), 26.8 (s, −CHMe2), 25.1 (s, THF), 23.7 (s, −CHMe2).
Anal. Calcd for C60H86N5O2S2Lu: C, 64.41; H, 7.53; N, 6.71. Found:
C, 64.29; H, 7.70; N, 6.81.
i
i
Synthesis of {[PhC(NC6H4 Pr2-2,6)2]Sc(μ-NC6H4 Pr2-2,6)}2 (6a).
In a tube with a Teflon stopcock, a toluene (10 mL) solution of 2,6-
diisopropylaniline (94 μL, 0.5 mmol) was added slowly to a stirred
toluene solution of complex 3a (0.376 g, 0.5 mmol). The tube was
taken out of the glovebox and placed in a 120 °C oil bath. The mixture
was stirred for 12 h, and the solvent was removed under reduced
pressure. The residue was washed with hexane and dried, leaving 6a as
a yellow powder (0.191 g, 58%, based on complex 3a). Single crystals
suitable for X-ray diffraction analysis were obtained by recrystallization
X-ray Crystallographic Analysis. Suitable crystals were sealed in
thin-walled glass capillaries under a microscope in the glovebox. Data
collections were performed on a Bruker SMART APEX or Bruker
SMART APEX II (at 293 or 296 K) diffractometer with CCD area
detector using graphite-monochromated Mo Kα radiation (λ =
0.71073 Å). The determination of crystal class and unit cell was
carried out by the SMART program package. The raw frame data were
processed using SAINT27 and SADABS28 to yield the reflection data
file. The structure was solved by using the SHELXTL program.29
Refinement was performed on F2 anisotropically by full-matrix least-
squares methods for all non-hydrogen atoms. Analytical scattering
factors for neutral atoms were used throughout the analysis. Except for
the hydrogen atoms on bridging carbons, hydrogen atoms were placed
at calculated positions and included in the structure calculation
without further refinement of the parameters. The hydrogen atoms on
bridging carbons were located by difference Fourier syntheses, and
their coordinates and isotropic parameters were refined. The residual
electron densities were of no chemical significance.
1
of 3a in toluene. H NMR (400 MHz, C6D6, 25 °C): δ 7.14 (m, 8H,
Ar), 6.96 (br m, 10H, Ar), 6.65 (m, 5H, Ar), 6.50 (m, 5H, Ar), 4.11−
2.62 (br m, 12H, −CHMe2), 1.74−1.51 (m, 24H, −CHMe2), 1.27 (br
s, 12H, −CHMe2), 0.90−0.81 (m, 18H, −CHMe2), 0.26−0.12 (m,
18H, −CHMe2). Anal. Calcd for C86H112N6Sc2: C, 78.26; H, 8.55; N,
6.37. Found: C, 78.45; H, 8.66; N, 6.23.
i
i
Synthesis of {[PhC(NC6H4 Pr2-2,6)2]Lu(μ-NC6H4 Pr2-2,6)}2 (6c).
Complex 6c was obtained as a yellow crystalline product in 62% yield
(0.244 g, based on complex 3c) by treating complex 3c (0.442 g, 0.5
mmol) with 2,6-diisopropylaniline (94 μL, 0.5 mmol) in toluene (30
mL), similarly to the preparation of 6a described above. 1H NMR (400
MHz, C6D6, 25 °C): δ 7.24 (d, J = 7.6 Hz, 1H, Ar), 7.14−7.06 (m, 5H,
Ar), 7.00−6.81 (m, 8H, Ar), 6.74−6.52 (m, 13H, Ar), 4.84 (s, 1H,
−CHMe2), 4.49 (m, 1H, −CHMe2), 4.05 (m, 2H, −CHMe2), 3.83
(m, 1H, −CHMe2), 3.65 (m, 1H, −CHMe2), 2.86−2.65 (m, 6H,
−CHMe2), 2.12−1.24 (m, 36H, −CHMe2), 0.89−0.11 (m, 36H,
−CHMe2). Anal. Calcd for C86H112N6Lu2: C, 65.38; H, 7.14; N, 5.32.
Found: C, 65.03; H, 7.24; N, 5.11.
ASSOCIATED CONTENT
* Supporting Information
■
S
CIF files, text, tables, and figures giving crystal data and
processing parameters, selected NMR spectra, and additional
experimental details. This material is available free of charge via
the Internet at http://pubs.acs.org.
i
Synthesis of [o-Me2NC6H4CH2C(NC6H4 Pr2-2,6)2]Lu-
(CH2C6H4NMe2-o)(SCH2C6H4NMe2-o)(THF) (7e). A THF (5 mL)
solution of S8 (0.016g, 0.0625 mmol) was added slowly to a stirred
THF (15 mL) solution of complex 3e (0.470 g, 0.5 mmol). After it
was stirred at room temperature for 12 h, the solution was
concentrated under vacuum and colorless crystals of 7e (0.496 g,
89%) formed after the solution stood for 2 days. 1H NMR (400 MHz,
C6D6, 25 °C): δ 8.17 (d, J = 7.2 Hz, 1H, Ar), 7.79 (d, J = 7.6 Hz, Ar),
7.20−6.84 (m, 14H, Ar), 6.70−6.62 (m, 2H, Ar), 4.41 (s, 2H, o-
Me2NPhSCH2−), 3.94 (br s, 6H, o-Me2NPhCH2−amidinate and
−CHMe2), 3.56 (br s, 4H, THF), 2.71 (br s, 12H,
−CH2C6H4NMe2-oalkyl and o-Me2NPhSCH2−), 1.94 (s, 2H,
−CH2C6H4NMe2-oalkyl), 1.87 (s, 6H, o-Me2NPhCH2−amidinate), 1.46
(br s, 18H, −CHMe2), 1.04 (br s, 10H, −CHMe2 and THF). 13C
NMR (100 MHz, C6D6, 25 °C): δ 179.3 (s, NCN), 152.7 (s, Ar),
152.2 (s, Ar), 145.4 (br s, Ar), 144.9 (s, Ar), 143.5 (br s, Ar), 142.7 (s,
Ar), 141.3 (s, Ar), 140.9 (s, Ar), 132.0 (s, Ar), 131.8 (s, Ar), 129.4 (s,
Ar), 128.4 (s, Ar), 127.2 (s, Ar), 126.9 (s, Ar), 126.5 (s, Ar), 125.1 (s,
Ar), 125.0 (s, Ar), 124.3 (s, Ar), 123.5 (s, Ar), 120.5 (s, Ar), 119.4
(Ar), 119.3 (Ar), 118.7 (s, Ar), 71.2 (s, THF), 47.7 (s,
−CH2C6H4NMe2-oalkyl), 47.5 (s, o-Me2NPhSCH2−), 45.5 (s,
−CH2C6H4NMe2-oalkyl), 44.6 (s, o-Me2NPhCH2−amidinate), 30.4 (s, o-
Me2NPhCH2−amidinate), 28.3 (s, −CHMe2), 28.1 (s, o-
Me2NPhSCH2−), 27.2 (s, −CHMe2), 25.5 (s, THF), 25.4 (s,
AUTHOR INFORMATION
Corresponding Authors
*E-mail for L.Z.: lixinzh@fudan.edu.cn.
*E-mail for X.Z.: xgzhou@fudan.edu.cn.
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank the NFSC, the Ministry of Education of China, the
China Postdoctoral Science Foundation, and Fudan University
for financial support.
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