Synthesis of Carbamoylphosphates from Isocyanates Catalyzed by Rare-Earth-Metal Alkyl Complexes with a Silicon-Linked Diarylamido Ligand

Article abstract of DOI:10.1021/acs.organomet.0c00627

Neutral rare-earth-metal monoalkyl complexes and anionic rare-earth-metal dialkyl complexes with a silicon-linked diarylamido ligand were synthesized and characterized, and their catalytic activities toward the additions of dialkyl phosphites to isocyanat

Full text of DOI:10.1021/acs.organomet.0c00627

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Article
Synthesis of Carbamoylphosphates from Isocyanates Catalyzed by
Rare-Earth-Metal Alkyl Complexes with a Silicon-Linked Diarylamido
Ligand
Xiancui Zhu,* Dianjun Guo, Yiwei Zhang, Yun Wei, Shuangliu Zhou, Mengchen Xu, Shaowu Wang,*
Yuanqing Yang, and Yawen Qi
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ABSTRACT: Neutral rare-earth-metal monoalkyl complexes and
anionic rare-earth-metal dialkyl complexes with a silicon-linked
diarylamido ligand were synthesized and characterized, and their
catalytic activities toward the additions of dialkyl phosphites to
isocyanates were developed. Reactions of rare-earth-metal trialkyl
complexes RE(CH2SiMe3)3(THF)2 with a silicon-linked diaryl-
amine ligand in n-hexane afforded the neutral rare-earth-metal
monoalkyl complexes LRE(CH2SiMe3)(THF)2 (RE = Y (1), Er
(2); L = (Me2Si)(2,6-iPr2C6H3N)2) in good yields. The dinuclear
rare-earth-metal chlorides [LRE(μ-Cl)(THF)2]2 (RE = Y (3), Er
(4)) were synthesized by the salt metathesis reaction of H2L,
nBuLi, and anhydrous RECl3. Treatment of the rare-earth-metal
chlorides with 4 equiv of LiCH2SiMe3 in toluene generated the corresponding discrete heterobimetallic rare-earth-metal dialkyl
complexes LRE(CH2SiMe3)2(THF)Li(THF)4 (RE = Y (5), Er (6)). Further investigation showed that a wide variety of
carbamoylphosphates were efficiently synthesized in high to excellent yields (up to 99%) via the additions of dialkyl phosphites to
various alkyl- and aryl-substituted isocyanates in the presence of 0.1 mol % rare-earth-metal monoalkyl or dialkyl complexes as
catalysts under solvent-free conditions at room temperature within 5 min, which provided a green and highly efficient method for the
rapid construction of C−P bonds to afford various carbamoylphosphate derivatives.
Scheme 1. Synthetic Methods for Carbamoylphosphate
Derivatives
INTRODUCTION
■
The formation of C−P bonds to construct organophosphorus
compounds, such as hydroxyphosphonates, aminophospho-
nates, phosphaguanidines, and phosphaureas, is of great
importance and significance due to their wide application in
industrial, agricultural, and medicinal areas.1 In contrast to the
α-functional phosphonic acid derivatives, carbamoylphospho-
nates (CPOs) are important scaffolds and synthons and have
attracted wide attention in biomedical and clinical research.2
Further investigation showed that CPOs have an important
antiviral activity by controlling tumor cell proliferation and
dissemination, and they also serve as inhibiters of matrix
metalloproteinases (MMP) associated with a variety of
diseases.3 However, the efficient synthesis of CPOs has
remained largely unexplored. It is well-known that common
methods for the preparation of CPO derivatives involve the
Schmidt reaction,4 the Arbuzov reaction,5 and the substitution
reaction between phosphonoformates and amines (Scheme
1b−d).6 Very recently, the reactions of phosphoramides and
alcohols can achieve CPOs via phosphorylation and oxygen-
ation using I2 as a catalyst or using nBu4NI as a catalyst through
an electrochemical method (Scheme 1e).7 Among the
aforementioned methods, several reagents, such as acylphosph-
onates, phosphonoformates, carbamoyl chlorides, and phos-
phoramides, are required for synthesis according to the
literature procedures. In contrast to the commercially available
isocyanates, the addition of dialkyl phosphites to isocyanates is
Received: September 21, 2020
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regarded as the most straightforward and 100% atom-
economical route for the preparation of CPOs (Scheme 1a),
however, only a limited number of catalytic systems have been
used for this transformation so far.
Scheme 2. Synthesis of the Rare-Earth-Metal Alkyl
Complexes and Chlorides
Strong bases, such as sodium and triethylamine, can
smoothly catalyze the addition reaction of dialkyl phosphites
to isocyanates.8 Kaboudin and co-workers found that 0.1 equiv
of anhydrous calcium chloride as a Lewis base catalyst can
promote the addition reaction to prepare CPOs in moderate
yields (≤65%).9 Raju et al. developed the silica-supported
Lewis acid catalyst SiO2-CeCl3·7H2O to synthesize CPOs via
the addition of diethyl phosphite to aromatic isocyanates under
heating or ultrasonication conditions.10 Challenges still exist
despite these recent advances, such as high catalyst loading,
low yields of the desired products, long reaction times, limited
scope of isocyanates, and harsh conditions. Therefore, the
development of highly efficient catalysts for the preparation of
CPOs under mild conditions is still strongly required.
Bridged ancillary ligands have been widely used in rare-
earth-metal complexes because such ligands have a powerful
electronic and steric tuning capability to stabilize highly
electrophilic rare-earth-metal ions, such as phenylene-bridged
bis(β-diketiminate), carbon-bridged bis(thiol), piperazidine-
bridged bis (phenolate), pyridine-bridged bis(arylamido), and
furan- and silylene-bridged ancillary ligands.11 It is reported
that group 4 complexes bearing silylene-bridged cyclo-
pentadiene derivatives have good catalytic activities in
propylene polymerization.12 An yttrium complex with a chiral
silicon-linked amido-indenyl ligand can catalyze the intra-
molecular hydroamination of olefins with high enantioselec-
tivity.13 We have found that rare-earth-metal amides with a
silicon-bridged diamido ligand exhibit high catalytic properties
for the cyclotrimerization or cyclodimerization of the
isocyanates.14 These results prompted us to explore the
potential activity of these complexes as catalysts for C−P bond
formation. Herein we will report newly synthesized neutral
rare-earth-metal monoalkyl and anionic rare-earth-metal dialkyl
complexes supported by a silicon-linked diarylamido ligand
catalyze the additions of dialkyl phosphites to various
isocyanates for the green synthesis of the CPO derivatives
with a high efficiency.
nitrogen atoms of the ligand and two oxygen atoms of THF
forming the basal plane and a carbon atom of the alkyl species
occupying the apical position (Figure 1). It is interesting that
Figure 1. Representative molecular structure of complexes 1 and 2.
Hydrogen atoms and isopropyl groups on phenyl rings are omitted for
clarity. Selected bond lengths (Å) and bond angles (deg): for 1, Y1−
N1 2.253(2), Y1−N2 2.221(2), Y1−C35 2.395(3), Y1−O1 2.390(2),
Y1−O2 2.3488(19), N(1)−Y(1)−N(2) 70.60(8), N(1)−Y(1)−
C(35) 119.72(10), N(2)−Y(1)−C(35) 109.76(10), O(1)−Y(1)−
C(35) 89.90(10), O(2)−Y(1)−C(35) 97.10(9); for 2, Er1−N1
2.212(8), Er1−N2 2.175(9), Er1−C35 2.43(2), Er1−O1 2.396(8),
Er1−O2 2.361(11), N(1)−Er(1)−N(2) 72.0(3), N(1)−Er(1)−
C(35) 102.4(6), N(2)−Er(1)−C(35) 100.6(6), O(1)−Er(1)−
C(35) 97.8(6), O(2)−Er(1)−C(35) 111.4(7).
RESULTS AND DISCUSSION
■
Synthesis and Structures of the Rare-Earth-Metal
Alkyl Complexes and Chlorides. Neutral rare-earth-metal
monoalkyl complexes LRE(CH2SiMe3)(THF)2 (RE = Y (1),
Er (2); L = (Me2Si)(2,6-iPr2C6H3N)2) were synthesized in
good yields (1, 82%; 2, 80%) by the reactions of the rare-earth-
metal trialkyl complexes RE(CH2SiMe3)3(THF)2 with an
equimolar amount of the Me2Si-linked diarylamine ligand
H2L via alkane elimination in n-hexane at room temperature
(Scheme 2, path 1). Complexes 1 and 2 are sensitive to air and
moisture and have a good solubility in n-hexane, toluene, and
the two Y−N(amido) bond lengths in 1 are not equivalent:
one is 2.253(2) Å, while the other is 2.221(2) Å. The same
phenomenon was also observed in the Y−O bond lengths
(2.390(2) Å vs 2.3488(19) Å). The Y1−C35 bond length of
2.395(3) Å is comparable to those in a five-coordinate β-
diketiminato yttrium alkyl complex (2.392(4), 2.394(3) Å),15a
however, it is slightly shorter than that in an amidopyridinate-
ligated yttrium alkyl complex (2.421(4) Å).15c
1
THF. The H NMR (500 MHz, C6D6) spectrum of 1 clearly
The salt metathesis reactions of the ligand H2L with nBuLi in
THF at −78 °C, followed by treatment with 1 equiv of
anhydrous RECl3 at room temperature, after workup gave the
centrosymmetric dinuclear rare-earth-metal chlorides [LRE(μ-
Cl)(THF)2]2 (RE = Y (3), Er (4)) (Scheme 2, path 2). The
structure of 4 was determined by single-crystal X-ray
diffraction. Although the quality of the structural data of 3 is
not satisfactory, the 1H NMR (500 MHz, toluene-d8) spectrum
of 3 clearly proved the existence of the Me2Si-linked dianiline
group coordinated to the yttrium ions in a N,N-bidentate
proves the presence of the Y−CH2SiMe3 moiety, exhibiting a
doublet at −0.38 ppm (2JY−H = 3.5 Hz) due to coupling with
the yttrium ion, which was further confirmed by a doublet at
28.3 ppm (1JY−C = 45.0 Hz) in the 13C{1H} NMR (125 MHz,
C6D6) spectrum (Figures S1 and S2 in the Supporting
Information). The coupling constants are similar to those
reported for yttrium alkyl complexes.15
Single-crystal X-ray analyses revealed that 1 and 2 adopt a
distorted-square-pyramidal coordination geometry, with two
B
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fashion (Figure S3). The molecular structure of 4 is shown in
Figure 2. In the dinuclear rare-earth-metal chlorides, each
Figure 3. Representative molecular structure of complexes 5 and 6.
Hydrogen atoms and isopropyl groups on phenyl rings are omitted for
clarity. Selected bond lengths (Å) and bond angles (deg): for 5, Y1−
N1 2.288(3), Y1−N2 2.282(3), Y1−C27 2.438(3), Y1−C31
2.435(4), Y1−O1 2.438(3), N(1)−Y(1)−N(2) 69.51(10), N(1)−
Y(1)−C(31) 108.54(13), N(2)−Y(1)−C(31) 122.88(12); for 6,
Er1−N1 2.279(6), Er1−N2 2.281(5), Er1−C27 2.411(7), Er1−C31
2.401(12), Er1−O1 2.432(5), N(1)−Er(1)−N(2) 70.0(2), N(1)−
Er(1)−C(31) 109.1(11), N(2)−Er(1)−C(31) 121.3(6).
Figure 2. Molecular structure of complex 4. Hydrogen atoms and
isopropyl groups on phenyl rings are omitted for clarity. Selected
bond lengths (Å) and bond angles (deg): Er1−N1 2.220(4), Er1−N2
2.200(4), Er1−Cl1 2.7182(16), Er1−Cl1i 2.7892(15), Er1−O1
2.369(4), Er1−O2 2.424(4), N(1)−Er(1)−N(2) 73.05(14), Cl(1)−
Y(1)−Cli(35) 73.47(5).
2.224(6)−2.318(6) Å in [(TpMe2)2Y][((Me3Si)2N)2Y(CH2)-
SiMe2N(SiMe3)] (Tp = tris(pyrazolyl)borate).17
Catalytic Activity. The catalytic addition of diisopropyl
phosphite to phenyl isocyanate for the preparation of
diisopropyl anilinocarbonylphosphonate was employed as the
model reaction in our initial screening of the newly synthesized
catalysts, and the results are presented in Table 1. It is
remarkable that, in the presence of 2 mol % of complex 1, the
addition product of 7a could be quantitatively obtained in
THF at room temperature within 5 min (entry 1). Decreasing
the catalyst loading from 2 mol % to 0.1 mol % also afforded 7a
in excellent yields (entries 2−4). When the catalyst loading
was decreased further to 0.05 mol %, the desired product was
metal ion is coordinated by two nitrogen atoms of the ligand,
two oxygen atoms of THF, and two chlorides in a bridged
form, displaying a distorted-octahedral geometry. Although 4
has a centrosymmetrical structure, the two Er−N(amido)
bond lengths (2.220(4) Å vs 2.200(4) Å), Er−Cl bond lengths
(2.7182(16) Å vs 2.7892(15) Å), and Er−O bond lengths
(2.369(4) Å vs 2.424(4) Å) around the same metal center are
not equal, which is similar to the case observed in 1 and 2.
Treatment of dinuclear rare-earth-metal chlorides with 2
equiv of LiCH2SiMe3 in toluene at 0 °C afforded the rare-
earth-metal monoalkyl complexes 1 and 2 in moderate yield
(1, 57%; 2, 59%). Due to the relatively low transformation
efficiency in comparison to the alkane elimination, the
preparation of 1 and 2 adopted path 1 in Scheme 2. When
the amount of LiCH2SiMe3 was increased to 4 equiv, the
reactions between the rare-earth-metal chlorides and organo-
lithium LiCH2SiMe3 under the same conditions gave the
discrete heterobimetallic rare-earth-metal dialkyl complexes
LRE(CH2SiMe3)2(THF)Li(THF)4 (RE = Y (5), Er (6)) in
64% and 60% yields, respectively (Scheme 2, path 3). As
shown in Figure 3, complexes 5 and 6 are discrete ion-pair
rare-earth-metal dialkyl complexes, containing a bidentate
diamido group [(Me2Si)(2,6-iPr2C6H3N)2], two alkyl groups
CH2SiMe3, and a molecule of THF, forming a five-coordinate
rare-earth-metal anionic species and four-THF-coordinated
lithium cationic species. The coordination geometry of anionic
rare-earth-metal complex 5 is not fundamentally different from
that of its neutral counterpart 1. The position of the molecule
of THF in yttrium monoalkyl complex 1 is replaced by an alkyl
group, forming the anionic yttrium dialkyl counterpart 5.
However, the bond lengths Y1−N1 2.288(3) Å and Y1−N2
2.282(3) Å in 5 are longer than those of 2.253(2) Å and
2.221(2) Å in 1. Similarly, the bond lengths of Y−C(alkyl)
2.438(3) Å and 2.435(4) Å in 5 are much longer than that of
2.395(3) Å in 1. The formation of 5 and 6 is similar to the
reactions of [Me2Si(NLiPh)2] with RECl3, followed by
treatment with CpNa to produce the anionic rare-earth-metal
complexes {[Me2Si(NPh)2]LnCp2}{Li(DME)3} (Ln = Yb,
Sm).16 The Y−N(amido) bond lengths in the range 2.288(3)−
2.282(3) Å in 5 are comparable to those in the range
Table 1. Optimization of the Reaction Conditions for the
a
Addition of Diisopropyl Phosphite to Phenyl Isocyanate
b
entry
cat. (mol %)
solvent
THF
THF
THF
THF
yield (%)
1
2
3
4
5
6
7
8
1 (2)
1 (1)
99
99
99
98
47
97
98
96
99
95
0
1 (0.5)
1 (0.1)
1 (0.05)
1 (0.1)
1 (0.1)
1 (0.1)
1 (0.1)
2 (0.1)
3 (0.1)
4 (0.1)
5 (0.1)
6 (0.1)
THF
n-hexane
toluene
Et2O
solvent-free
solvent-free
toluene
toluene
solvent-free
solvent-free
solvent-free
c
9
10
11
12
13
14
15
0
99
94
0
a
Reaction conditions: phenyl isocyanate (2.0 mmol), diisopropyl
b
c
phosphite (2.0 mmol). Isolated yields. The addition sequence was
isocyanate/diisopropyl phosphite/cat. with vigorous stirring under
solvent-free conditions.
C
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isolated in 47% yield (entry 5). It is worth noting that the
catalytic system has a good compatibility with different
solvents, such as n-hexane, toluene, and Et2O (entries 6−8).
To our delight, when the catalytic addition was carried out
under solvent-free conditions, the carbamoylphosphonate
product was isolated in 99% yield (entry 9). In sharp contrast
to 1 and 2, dinuclear rare-earth-metal chlorides 3 and 4
showed no activity in this catalytic reaction (entries 11 and
12). Anionic rare-earth-metal dialkyl complexes 5 and 6 can
successfully promote the catalytic addition with the isolation of
excellent yields of the product 7a. In contrast to erbium
catalysts, yttrium complexes 1 and 5 exhibited better catalytic
efficiency (entries 9, 10, 13, and 14), suggesting that a rare-
earth metal with a large ionic radius has a positive influence on
the catalytic reaction. The addition of diisopropyl phosphite to
phenyl isocyanate without the catalyst could not take place,
and no product was observed under the same conditions
(entry 15).
Next, the scopes of various isocyanates and dialkyl
phosphites under the optimized conditions were investigated
(Table 2). It is interesting to find that the isocyanates with
either electron-donating or electron-withdrawing groups on
the phenyl rings can smoothly react with diisopropyl phosphite
to afford the corresponding carbamoylphosphates (7b−k) in
good to high yields in the presence of 0.1 mol % of catalyst 1.
For example, the bulky 4-isopropyl and 2,6-diisopropyl
phenylisocyanates could be used in the reaction, affording
the products 7d,e in 97% and 93% yields, respectively. Strongly
electron withdrawing groups, such as nitro-, halogen (Cl, Br)-,
and tosyl-substituted phenyl isocyanates, also worked well with
diisopropyl phosphite, affording the products 7g−l in 87−97%
yields. Moreover, the catalyst 1 was also compatible with
branched (isopropyl and tert-butyl), linear (ethyl), and
cyclohexyl-substituted aliphatic isocyanates and the outputs
of 7m−p still remained in excellent efficiency (96−98%
yields). In addition to diisopropyl phosphite, diethyl phosphite
and dibenzyl phosphite were also suitable for the addition with
alkyl- and aryl-substituted isocyanates, producing the corre-
sponding carbamoylphosphate derivatives 7q−u in 92−99%
yields.
On the basis of the 1H NMR monitoring control
experiments (Figure S70) and previously reported mechanism
studies of catalysis by rare-earth-metal complexes of the
addition of dialkyl phosphites to CN and CO bonds18
and cyclization of isocyanates,14 a plausible catalytic mecha-
nism was proposed (Scheme 3): the acid−base reaction
Scheme 3. Possible Mechanism for the Catalytic Addition
a
Table 2. Scope of the Isocyanates and Dialkyl Phosphites
a
entry
R1
R2
product
yield (%)
1
2
3
4
5
6
7
8
9
C6H5
iPr
iPr
iPr
iPr
iPr
iPr
iPr
iPr
iPr
iPr
iPr
iPr
iPr
iPr
iPr
iPr
Et
7a
7b
7c
7d
7e
7f
99
97
99
97
93
98
96
97
95
87
95
97
97
98
98
96
99
97
98
92
94
3-MeC6H4
4-MeC6H4
4-iPrC6H4
2,6-iPr2C6H3
4-MeOC6H4
2-ClC6H4
3-ClC6H4
4-BrC6H4
4-O2NC6H4
3,4-Cl2C6H3
4-MeC6H4SO2
iPr
between rare-earth-metal alkyl complexes and dialkyl phos-
phite (phosphonate as its tautomeric form) gave the
intermediate A, which then formed isocyanate-coordinated
intermediate C due to the strong oxytropism of the rare-earth-
metal ions (path I). Meanwhile, the intermediate C can also be
derived from the interaction of the intermediate B and dialkyl
phosphite with the release of a molecule of TMS (path II).
Electron deficiency on the carbon atom of isocyanate moiety in
C led to the addition of the phosphorus atom of dialkyl
phosphite, resulting in the formation of the intermediate D.
Then the interaction between D and another dialkyl phosphite
produced the final catalytic product CPOs and regenerated A
to fulfill a catalytic cycle.
7g
7h
7i
b
10
7j
11
12
13
14
15
16
17
18
19
20
21
7k
7l
7m
7n
7o
7p
7q
7r
7s
7t
tBu
cyclohexyl
ClCH2CH2
C6H5
4-iPrC6H4
3-ClC6H4
cyclohexyl
4-MeC6H4SO2
Et
Et
Bn
Bn
CONCLUSIONS
■
7u
In summary, we have demonstrated that both neutral rare-
earth-metal monoalkyl complexes and anionic rare-earth-metal
dialkyl complexes supported by the silicon-linked diamido
ligand can be synthesized through different pathways. Further
studies show that these complexes displayed a high catalytic
activity in the addition of dialkyl phosphites to a variety of
a
Reaction conditions unless specified otherwise: in a Schlenk reactor
were placed isocyanates (2.0 mmol) and dialkyl phosphites (2.0
mmol) with vigorous stirring until dissolution before adding the
catalyst 1 (2.0 μmol). Isolated yield. Diisopropyl phosphites (2.4
b
mmol).
D
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Anal. Calcd for C68H112N4O4Si2Cl2Y2·C6H14: C, 61.69; H, 8.82; N,
3.89. Found: C, 61.78; H, 9.16; N, 3.76. IR (KBr pellets, cm−1): ν
3075, 2963, 2874, 1852, 1622, 1461, 1439, 1383, 1360, 1351, 1331,
1262, 1193, 1088, 1043, 909, 804, 746.
isocyanates, providing a simple, mild, and highly efficient
method for the formation of various carbamoylphosphate
derivatives. Meanwhile, the rare-earth-metal alkyl complexes
catalytic systems have the advantages of simple operation, high
efficiency, low catalytic loadings, compatibility with a wide
range of substrates, and proceeding under solvent-free
conditions.
Preparation of [LEr(μ-Cl)(THF)2]2 (4). This complex was isolated
as pink crystals in 77% yield by treatment of a solution of H2L (0.50 g,
n
1.22 mmol) in THF with a solution of 1.6 M BuLi (1.56 mL, 2.50
mmol) in n-hexane, followed by reaction with a THF suspension of
ErCl3 (333 mg, 1.22 mmol) following a procedure similar to that for
the preparation of 3. Anal. Calcd for C68H112N4O4Si2Cl2Er2·C6H14: C,
55.64; H, 7.95; N, 3.51. Found: C, 55.56; H, 8.18; N, 3.43. IR (KBr
pellets, cm−1): ν 3066, 2961, 2869, 2869, 1921, 1854, 1794, 1622,
1591, 1436, 1322, 1258, 1197, 1139, 1106, 1043, 911, 788.
EXPERIMENTAL SECTION
■
Materials and Methods. All syntheses and manipulations of the
air- and moisture-sensitive materials were performed under dry argon
and an oxygen-free atmosphere, using standard Schlenk techniques or
in a glovebox. All solvents (THF, n-hexane, and toluene) were
refluxed and distilled over sodium benzophenone ketyl under argon
prior to use unless otherwise noted. RE(CH2SiMe3)3(THF)2,19
RECl3,20 (Me2Si)[(2,6-iPr2C6H3)NH]2,21 and LiCH2SiMe3 (0.8 M
solution in hexane) were prepared according to the reported methods.
Solid isocyanates were used without further purification. Liquid
isocyanates and diisopropyl, diethyl, and dibenzyl phosphites were
purchased from Aldrich and distilled prior to use. Elemental analysis
data were obtained on a PerkinElmer Model 2400 Series II elemental
analyzer. HRMS measurements were conducted with an Agilent
Model 6220 ESI-TOF mass spectrometer. 1H, 13C, and 31P NMR data
were obtained on a 300 MHz or a 500 MHz Bruker spectrometer.
Chemical shifts (δ) are reported in ppm. The J values are reported in
Hz. IR spectra were recorded on a Shimadzu FTIR-8400s
spectrometer (measurements of KBr pellets were performed in a
glovebox and protected by dry argon prior to IR determination).
Melting points were measured with a SGWX-4 instrument.
Preparation of LY(CH2SiMe3)2(THF)Li(THF)4 (5). To a solution
of 3 (0.50 g, 0.37 mmol) in toluene (5.0 mL) was added dropwise a
solution of 0.8 M LiCH2SiMe3 (2.0 mL, 1.60 mmol) in hexane with
rapid stirring at 0 °C. The mixture was stirred at room temperature
for 8 h. The solvent was evaporated under reduced pressure to yield a
viscous solid. Recrystallization from n-hexane afforded colorless
crystals of 5 (0.48 g, 64% yield). 1H NMR (500 MHz, C6D6,
ppm): δ 7.35 (d, J = 7.5 Hz, 1H, C6H3), 7.06 (d, J = 7.5 Hz, 2H, 6H3),
6.86 (t, J = 7.5 Hz, 2H, C6H3), 6.69 (t, J = 7.5 Hz, 1H, C6H3), 4.46
(br s, 2H, CH(CH3)2), 3.69 (br s, 2H, CH(CH3)2), 3.23 (s, 12H, α-
THF), 1.49−1.04 (m, 36H, β-THF and CH(CH3)2), 0.42 (s, 6H,
Si(CH3)2), 0.20 (s, 18H, Si(CH3)3), − 1.02 (s, 4H, CH2SiMe3). 13C
NMR (125 MHz, C6D6, ppm): δ 152.2, 143.8, 123.8, 117.9, 68.5 (α-
THF), 27.2, 26.7, 26.5 (β-THF), 25.1, 24.9, 4.1 (SiMe2). Anal. Calcd
for C54H102LiN2O5Si3Y·(−2THF): C, 61.71; H, 9.68; N, 3.13. Found:
C, 61.36; H, 9.29; N, 3.40. IR (KBr pellets, cm−1): ν 2310, 1589,
1458, 1438, 1361, 1328, 1195, 1111, 1043, 906, 829, 786. The
reaction of 3 with 2 equiv of LiCH2SiMe3 following a procedure
similar to the preparation of 5 produced complex 1 in 57% yield.
Preparation of LEr(CH2SiMe3)2(THF)Li(THF)4 (6). This complex
was isolated as pink crystals in 60% yield by treatment of 4 (0.50 g,
0.33 mmol) with 0.8 M LiCH2SiMe3 (1.8 mL, 1.44 mmol) following a
procedure similar to that for the preparation of 5. Anal. Calcd for
C54H102LiN2O5Si3Er·(−3THF): C, 55.95; H, 8.72; N, 3.11. Found: C,
56.25; H, 8.38; N, 3.45. IR (KBr pellets, cm−1): ν 2345, 1589, 1456,
1438, 1358, 1328, 1253, 1195, 1111, 1043, 906, 829. The reaction of
4 with 2 equiv of LiCH2SiMe3 following a procedure similar to the
preparation of 6 produced complex 2 in 59% yield.
General Procedure for the Addition of Dialkyl Phosphites
to Isocyanates (7a as an Example). A mixture of phenyl
isocyanate (2.0 mmol) and diisopropyl phosphite (2.0 mmol) was
stirred for 1 min. Complex 1 (2.0 μmol) was then added, and the
reaction mixture was rapidly stirred for 5 min. The clear liquid
mixture changed slowly to a white solid during the reaction. Water
was added, and the mixture was extracted with ethyl acetate (3 × 5
mL). The combined organic layers were dried over anhydrous
MgSO4, and the solvent was evaporated under reduced pressure after
filtration. The product 7a was recrystallized from a mixture of n-
hexane and ethyl acetate (0.56 mg, 99% yield).
X-ray Crystallographic Analyses. Suitable crystals of complexes
1 and 4−6 were sealed in thin-walled glass capillaries under argon.
Diffraction was performed on a Bruker SMART CCD area detector
diffractometer using graphite-monochromated Mo Kα radiation (λ =
0.71073 Å). An empirical absorption correction was applied using the
SADABS program.22 All structures were solved by direct methods,
completed by subsequent difference Fourier syntheses, and refined
anisotropically for all non-hydrogen atoms by full-matrix least-squares
calculations on F2 using the SHELXTL program package.23 All
hydrogen atoms were refined using a riding model.
Preparation of LY(CH2SiMe3)(THF)2 (1). To a solution of H2L
(0.41 g, 1.00 mmol) in n-hexane (10.0 mL) was added a solution of
Y(CH2SiMe3)3(THF)2 (0.49 g, 1.00 mmol) in n-hexane (10.0 mL).
The reaction mixture was stirred at room temperature for 4 h, and the
solvent was evaporated under reduced pressure to about 8.0 mL.
Colorless crystals were obtained after the solution was allowed to
1
stand at 0 °C for several days (0.60 g, 82% yield). H NMR (500
MHz, C6D6, ppm): δ 7.21 (d, 4H, J = 7.5 Hz, C6H3), 7.00 (t, J = 7.5
Hz, 2H, C6H3), 4.19 (br s, 4H, CH(CH3)2), 3.32 (t, J = 6.5 Hz, 8H,
α-THF), 1.36 (br s, 24H, CH(CH3)2), 1.04−1.01 (m, 8H, β-THF),
0.38 (s, 6H, Si(CH3)2), 0.21 (s, 9H, Si(CH3)3), − 0.38 (d, 2JY−H = 3.5
Hz, 2H, CH2SiMe3). 13C NMR (125 MHz, C6D6, ppm): δ 150.1,
1
142.6, 123.4, 119.6, 69.9 (α-THF), 28.3 (d, JY−C = 45.0 Hz), 27.6,
26.0, 25.1, 4.6 (SiMe2). Anal. Calcd for C38H67N2O2Si2Y: C, 62.60; H,
9.26; N, 3.84. Found: C, 62.96; H, 9.20; N, 3.84. IR (KBr pellets,
cm−1): ν 3061, 3026, 2963, 2871, 1917, 1859, 1796, 1620, 1586,
1461, 1439, 1383, 1358, 1325, 1255, 1195, 1110, 1054, 907, 882, 828,
786.
Preparation of LEr(CH2SiMe3)(THF)2 (2). This complex was
isolated as pink crystals in 80% yield by treatment of Er-
(CH2SiMe3)3(THF)2 (0.50 g, 0.87 mmol) with H2L (0.36 g, 0.87
mmol) following a procedure similar to that for the preparation of 1.
Anal. Calcd for C38H67N2O2Si2Er: C, 56.53; H, 8.36; N, 3.47. Found:
C, 56.90; H, 8.37; N, 3.40. IR (KBr pellets, cm−1): ν 3061, 3030,
2961, 2871, 1924, 1859, 1798, 1620, 1591, 1457, 1439, 1383, 1363,
1327, 1255, 1197, 1110, 1048, 907, 828, 786.
Preparation of [LY(μ-Cl)(THF)2]2 (3). To a solution of H2L (0.50
g, 1.22 mmol) in THF (10.0 mL) at −78 °C was added dropwise a
solution of 1.6 M nBuLi (1.56 mL, 2.50 mmol) in n-hexane with rapid
stirring. The mixture was slowly warmed to room temperature for 4 h;
a THF suspension of YCl3 (236 mg, 1.22 mmol) was then added to
the mixture. The reaction mixture was stirred at room temperature for
8 h. The solvent was evaporated under reduced pressure to yield a
pale yellow solid. Recrystallization from toluene afforded colorless
1
crystals of 3 (0.71 g, 87% yield). H NMR (500 MHz, toluene-d8,
ASSOCIATED CONTENT
ppm): δ 7.05 (s, 2H, C6H3), 7.01 (s, 4H, C6H3), 3.55 (s, 6H, α-THF),
3.49 (sept, J = 7.0 Hz, 4H, CH(CH3)2), 2.60 (s, 2H, α-THF), 1.44 (s,
8H, β-THF), 1.15 (d, J = 7.0 Hz, 24H, CH(CH3)2), 0.19 (s, 6H,
Si(CH3)2). 13C NMR (125 MHz, toluene-d8, ppm): δ 144.6, 139.3,
124.5, 123.4, 67.8 (α-THF), 28.6, 25.7 (β-THF), 23.8, 0.03 (SiMe2).
■
sı
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.organomet.0c00627.
E
https://dx.doi.org/10.1021/acs.organomet.0c00627
Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
Characterization data of compounds 7a−u, 1H, 13C, and
Anhui Normal University, Wuhu, Anhui 241000, People’s
Republic of China
Yawen Qi − Key Laboratory of Functional Molecular Solids,
Ministry of Education, Anhui Laboratory of Molecule-Based
Materials, College of Chemistry and Materials Science, Anhui
Normal University, Wuhu, Anhui 241000, People’s Republic
of China
31P NMR spectra for compounds 7a−u, and crystallo-
graphic data for complexes 1, 2, and 4−6 (PDF)
Accession Codes
CCDC 1969143−1969144, 2030786−2030787, and 2047086
contain the supplementary crystallographic data for this paper.
These data can be obtained free of charge via www.ccdc.ca-
m.ac.uk/data_request/cif, or by emailing data_request@ccdc.
cam.ac.uk, or by contacting The Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax:
+44 1223 336033.
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.organomet.0c00627
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
AUTHOR INFORMATION
■
The authors gratefully acknowledge the National Natural
Science Foundation of China (21672003, 22031001,
21871004, 21861162009 and 21672004).
Corresponding Authors
Xiancui Zhu − Key Laboratory of Functional Molecular Solids,
Ministry of Education, Anhui Laboratory of Molecule-Based
Materials, College of Chemistry and Materials Science, Anhui
Normal University, Wuhu, Anhui 241000, People’s Republic
of China; orcid.org/0000-0001-7354-3573;
REFERENCES
■
(1) (a) Gu, X.; Zhang, L.; Zhu, X.; Wang, S.; Zhou, S.; Wei, Y.;
Zhang, G.; Mu, X.; Huang, Z.; Hong, D.; Zhang, F. Synthesis of
Bis(NHC)-Based CNC-Pincer Rare-Earth-Metal Amido Complexes
and Their Application for the Hydrophosphination of Heterocumu-
lenes. Organometallics 2015, 34, 4553−4559. (b) Behrle, A. C.;
Schmidt, J. A. R. Insertion Reactions and Catalytic Hydrophosphi-
nation of Heterocumulenes using α-Metalated N,N-Dimethylbenzyl-
amine Rare-Earth-Metal Complexes. Organometallics 2013, 32, 1141−
1149. (c) Zhang, W.; Nishiura, M.; Mashiko, T.; Hou, Z. Half-
Sandwich o-N,N-Dimethylaminobenzyl Complexes over the Full Size
Range of Group 3 and Lanthanide Metals. Synthesis, Structural
Characterization, and Catalysis of Phosphine P−H Bond Addition to
Carbodiimides. Chem. - Eur. J. 2008, 14, 2167−2179. (d) Demmer, C.
S.; Krogsgaard-Larsen, N.; Bunch, L. Review on Modern Advances of
Chemical Methods for the Introduction of a Phosphonic Acid Group.
Chem. Rev. 2011, 111, 7981−8006. (e) Zhao, D.; Wang, R. Recent
developments in metal catalyzed asymmetric addition of phosphorus
nucleophiles. Chem. Soc. Rev. 2012, 41, 2095−2108.
Email: zxc0805@ahnu.edu.cn
Shaowu Wang − Key Laboratory of Functional Molecular
Solids, Ministry of Education, Anhui Laboratory of Molecule-
Based Materials, College of Chemistry and Materials Science,
Anhui Normal University, Wuhu, Anhui 241000, People’s
Republic of China; Anhui Laboratory of Clean Catalytic
Engineering, Anhui Laboratory of Functional Complexes for
Materials Chemistry and Application, College of Chemical
and Environmental Engineering, Anhui Polytechnic
University, Wuhu, Anhui 241000, People’s Republic of
China; orcid.org/0000-0003-1083-1468;
Email: swwang@mail.ahnu.edu.cn, wsw@ahpu.edu.cn
Authors
Dianjun Guo − Key Laboratory of Functional Molecular
Solids, Ministry of Education, Anhui Laboratory of Molecule-
Based Materials, College of Chemistry and Materials Science,
Anhui Normal University, Wuhu, Anhui 241000, People’s
Republic of China
Yiwei Zhang − Key Laboratory of Functional Molecular
Solids, Ministry of Education, Anhui Laboratory of Molecule-
Based Materials, College of Chemistry and Materials Science,
Anhui Normal University, Wuhu, Anhui 241000, People’s
Republic of China
Yun Wei − Key Laboratory of Functional Molecular Solids,
Ministry of Education, Anhui Laboratory of Molecule-Based
Materials, College of Chemistry and Materials Science, Anhui
Normal University, Wuhu, Anhui 241000, People’s Republic
of China
Shuangliu Zhou − Key Laboratory of Functional Molecular
Solids, Ministry of Education, Anhui Laboratory of Molecule-
Based Materials, College of Chemistry and Materials Science,
Anhui Normal University, Wuhu, Anhui 241000, People’s
Republic of China; orcid.org/0000-0002-0103-294X
Mengchen Xu − Key Laboratory of Functional Molecular
Solids, Ministry of Education, Anhui Laboratory of Molecule-
Based Materials, College of Chemistry and Materials Science,
Anhui Normal University, Wuhu, Anhui 241000, People’s
Republic of China
(2) (a) Reich, R.; Katz, Y.; Hadar, R.; Breuer, E. Carbarnoylphosph-
onate matrix metalloproteinase inhibitors 3: In vivo evaluation of
cyclopentylcarbamoylphosphonic acid in experimental metastasis and
angiogenesis. Clin. Cancer Res. 2005, 11, 3925−3929. (b) Frant, J.;
Veerendhar, A.; Chernilovsky, T.; Nedvetzki, S.; Vaksman, O.;
Hoffman, A.; Breuer, E.; Reich, R. Orally Active, Antimetastatic,
Nontoxic Diphenyl Ether-Derived Carbamoylphosphonate Matrix
Metalloproteinase Inhibitors. ChemMedChem 2011, 6, 1471−1477.
(c) Salomon, C. J.; Breuer, E. Facile ″one-pot″ preparation of
phosphonothiolformates. Useful reagents for the synthesis of
carbamoylphosphonates. Synlett. 2000, 6, 815−816. (d) Hoffman,
A.; Qadri, B.; Frant, J.; Katz, Y.; Bhusare, S. R.; Breuer, E.; Hadar, R.;
Reich, R. Carbamoylphosphonate matrix metalloproteinase inhibitors
6: cis-2-aminocyclohexylcarbamoylphosphonic acid, a novel orally
active antimetastatic matrix metalloproteinase-2 selective inhibitor -
Synthesis and pharmacodynamic and pharmacokinetic analysis. J.
Med. Chem. 2008, 51, 1406−1414.
(3) (a) Breuer, E.; Salomon, C. J.; Katz, Y.; Chen, W.; Lu, S.;
Roschenthaler, G.-V.; Hadar, R.; Reich, R. Carbamoylphosphonates, a
̈
new class of in vivo active matrix metalloproteinase inhibitors. 1.
Alkyl- and cycloalkylcarbamoylphosphonic acids. J. Med. Chem. 2004,
47, 2826−2832. (b) Farkas, E.; Katz, Y.; Bhusare, S.; Reich, R.;
̈
̈
Roschenthaler, G.-V.; Konigsmann, M.; Breuer, E. Carbamoylphosph-
onate-based matrix metalloproteinase inhibitor metal complexes:
solution studies and stability constants. Towards a zinc-selective
binding group. JBIC, J. Biol. Inorg. Chem. 2004, 9, 307−315. (c) Reich,
R.; Hoffman, A.; Veerendhar, A.; Maresca, A.; Innocenti, A.; Supuran,
C. T.; Breuer, E. Carbamoylphosphonates Control Tumor Cell
Proliferation and Dissemination by Simultaneously Inhibiting
Carbonic Anhydrase IX and Matrix Metalloproteinase-2. Toward
Yuanqing Yang − Key Laboratory of Functional Molecular
Solids, Ministry of Education, Anhui Laboratory of Molecule-
Based Materials, College of Chemistry and Materials Science,
F
https://dx.doi.org/10.1021/acs.organomet.0c00627
Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
Nontoxic Chemotherapy Targeting Tumor Microenvironment. J.
Med. Chem. 2012, 55, 7875−7882. (d) Li, N. G.; Shi, Z. H.; Tang, Y.
P.; Lian, Y.; Duan, J. A. Discovery of Selective Small Molecular TACE
Inhibitors for the Treatment of Rheumatoid Arthritis. Curr. Med.
Chem. 2012, 19, 2924−2956.
furyl)indenyl]zirconocene system. J. Organomet. Chem. 2001, 622,
143−148. (i) Wang, B.; Nishiura, M.; Cheng, J.; Hou, Z. Half-
sandwich scandium boryl complexes bearing a silylene-linked
cyclopentadienyl-amido ligand. Dalton Trans. 2014, 43, 14215−
14218.
(12) Veghini, D.; Henling, L. M.; Burkhardt, T. J.; Bercaw, J. E.
Mechanisms of Stereocontrol for Doubly Silylene-Bridged Cs- and C1-
Symmetric Zirconocene Catalysts for Propylene Polymerization.
Synthesis and Molecular Structure of Li2[(1,2-Me2Si)2{C5H2-4-
(1R,2S,5R-menthyl)}{C5H-3,5-(CHMe2)2)}]·3THF and [(1,2-
Me2Si)2{η5-C5H2-4-(1R,2S,5R-menthyl)}{η5-C5H-3,5-(CHMe2)2}]-
ZrCl2. J. Am. Chem. Soc. 1999, 121, 564−573.
(13) Chai, Z.; Hua, D.; Li, K.; Chu, J.; Yang, G. A novel chiral
yttrium complex with a tridentate linked amido-indenyl ligand for
intramolecular hydroamination. Chem. Commun. 2014, 50, 177−179.
(14) (a) Wu, Y.; Wang, S.; Zhu, X.; Yang, G.; Wei, Y.; Zhang, L.;
Song, H. Synthesis, Characterization, and Catalytic Activity of Rare
Earth Metal Amides Supported by a Diamido Ligand with a
CH2SiMe2 Link. Inorg. Chem. 2008, 47, 5503−5511. (b) Zhu, X.;
Fan, J.; Wu, Y.; Wang, S.; Zhang, L.; Yang, G.; Wei, Y.; Yin, C.; Zhu,
H.; Wu, S.; Zhang, H. Synthesis, Characterization, Selective Catalytic
Activity, and Reactivity of Rare Earth Metal Amides with Different
Metal-Nitrogen Bonds. Organometallics 2009, 28, 3882−3888.
(15) (a) Zhu, X.; Li, Y.; Guo, D.; Wang, S.; Wei, Y.; Zhou, S.
Versatile reactivities of rare-earth metal dialkyl complexes supported
by a neutral pyrrolylfunctionalized β-diketiminato ligand. Dalton
Trans. 2018, 47, 3947−3957. (b) Guo, L. P.; Zhu, X. C.; Zhang, G.
C.; Wei, Y.; Ning, L. X.; Zhou, S. L.; Feng, Z. J.; Wang, S. W.; Mu, X.
L.; Chen, J.; Jiang, Y. Z. Synthesis and Characterization of Organo-
Rare-Earth Metal Monoalkyl Complexes Supported by Carbon σ-
Bonded Indolyl Ligands: High Specific Isoprene 1,4-Cis Polymer-
ization Catalysts. Inorg. Chem. 2015, 54, 5725−5731. (c) Karpov, A.
V.; Shavyrin, A. S.; Cherkasov, A. V.; Fukin, G. K.; Trifonov, A. A.
Reactions of Bis(alkyl)yttrium Complexes Supported by Bulky N,N
Ligands with 2,6-Diisopropylaniline and Phenylacetylene. Organo-
metallics 2012, 31, 5349−5357.
(16) Zhou, L.; Yao, Y.; Li, C.; Zhang, Y.; Shen, Q. Synthesis and
Characterization of a Series of New Lanthanide Derivatives Supported
by Silylene-Bridged Diamide Ligands and Their Catalytic Activities
for the Polymerization of Methyl Methacrylate. Organometallics 2006,
25, 2880−2885.
(17) Han, F.; Zhang, J.; Yi, W.; Zhang, Z.; Yu, J.; Weng, L.; Zhou, X.
γ-Deprotonation of Anionic Bis(trimethylsilyl)amidolanthanide Com-
plexes with a Countered [(TpMe2)2Ln]+ Cation. Inorg. Chem. 2010,
49, 2793−2798.
(18) (a) Wu, Q. M.; Zhou, J.; Yao, Z. G.; Xu, F.; Shen, Q.
Lanthanide Amides [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 Catalyzed
Hydrophosphonylation of Aryl Aldehydes. J. Org. Chem. 2010, 75,
7498−7501. (b) Zhu, X.; Wang, S.; Zhou, S.; Wei, Y.; Zhang, L.;
Wang, F.; Feng, Z.; Guo, L.; Mu, X. Lanthanide Amido Complexes
Incorporating Amino-Coordinate-Lithium Bridged Bis(indolyl) Li-
gands: Synthesis, Characterization, and Catalysis for Hydrophospho-
nylation of Aldehydes and Aldimines. Inorg. Chem. 2012, 51, 7134−
7143.
(4) Sprecher, M.; Kost, D. The Schmidt Reaction of Dialkyl
Acylphosphonates. J. Am. Chem. Soc. 1994, 116, 1016−1026.
(5) Reetz, T.; Chadwick, D. H.; Hardy, E. E.; Kaufman, S.
Carbamoylphosphonates. J. Am. Chem. Soc. 1955, 77, 3813−3816.
(6) (a) Harel, E.; Rubinstein, A.; Chen, W.; Breuer, E.; Tirosh, B.
Aminoalkylcarbamoylphosphonates reduce TNF alpha release from
activated immune cells. Bioorg. Med. Chem. Lett. 2010, 20, 6518−
6523. (b) Veerendhar, A.; Cohen, S.; Frant, J.; Supuran, C. T.; Reich,
R.; Breuer, E. Synthesis of Enantiomeric Aminoalkylcarbamoyl-
phosphonates and Their Evaluation as Dual-Action Anticancer
MMP and Carbonic Anhydrase Inhibitors. Heteroat. Chem. 2015,
26, 257−269. (c) Beylis, I.; Frant, J.; Mussai, N.; Reich, R.; Breuer, E.
Carbamoylphosphonates Part 7. An efficient method for the synthesis
of hindered carbamoylphosphonates using 4-nitrophenoxycarbonyl-
phosphonate diesters. Tetrahedron Lett. 2008, 49, 2875−2877.
(7) (a) Wu, Y. H.; Wu, Q. L.; Wang, W. P.; Wang, X. C.; Quan, Z. J.
Iodine-Promoted Rapid Construction of Carbamoylphosphonates
from Phosphinecarboxamides. Adv. Synth. Catal. 2018, 360, 2382−
2388. (b) Wu, Q. L.; Chen, X. G.; Huo, C. D.; Wang, X. C.; Quan, Z.
J. Electrochemically driven P−H oxidation and functionalization:
synthesis of carbamoylphosphonates from phosphoramides and
alcohols. New J. Chem. 2019, 43, 1531−1535.
(8) Fox, R. B.; Venezky, D. L. The Base-catalyzed Reaction of
Dialkyl Phosphonates with Isocyanates. J. Am. Chem. Soc. 1956, 78,
1661−1663.
(9) Kaboudin, B.; Zahedi, H. A Novel and Convenient Method for
Synthesis of Carbamoyl and Thiocarbamoyl Phosphonates. Heteroat.
Chem. 2009, 20, 250−253.
(10) Rao, D. S.; Madhava, G.; Rasheed, S.; Basha, S. K. T.;
Devamma, M. N. L.; Raju, C. N. CeCl3.7H2O-SiO2 Catalyzed
Ultrasonicated Solvent-free Synthesis of Carbamoyl/ Carbamothioyl
phosphonates and Antimicrobial Activity Evaluation. Phosphorus,
Sulfur Silicon Relat. Elem. 2015, 190, 574−584.
(11) (a) Yao, Y. M.; Xu, X. P.; Liu, B.; Zhang, Y.; Shen, Q. Carbon-
bridged bis(phenolato)lanthanide alkoxides: Syntheses, structures,
and their application in the controlled polymerization of epsilon-
caprolactone. Inorg. Chem. 2005, 44, 5133−5140. (b) Konkol, M.;
Kondracka, M.; Voth, P.; Spaniol, T. P.; Okuda, J. Rare-earth metal
alkyl and hydrido complexes containing a thioether-functionalized
bis(phenolato) ligand: Efficient catalysts for olefin hydrosilylation.
Organometallics 2008, 27, 3774−3784. (c) Zhou, S.; Wang, S.; Yang,
G.; Li, Q.; Zhang, L.; Yao, Z.; Zhou, Z.; Song, H. Synthesis, Structure,
and Diverse Catalytic Activities of [Ethylenebis(indenyl)]lanthanide-
(III) Amides on N-H and C-H Addition to Carbodiimides and ε-
Caprolactone Polymerization. Organometallics 2007, 26, 3755−3761.
(d) Sun, S.; Sun, Q.; Zhao, B.; Zhang, Y.; Shen, Q.; Yao, Y.
Unexpected C−H Bond Activation Promoted by Bimetallic
Lanthanide Amido Complexes Bearing a META-Phenylene-Bridged
Bis(β-diketiminate) Ligand. Organometallics 2013, 32, 1876−1881.
(e) Zhang, Z. J.; Xu, X. P.; Sun, S.; Yao, Y. M.; Zhang, Y.; Shen, Q.
Facile syntheses of bimetallic ytterbium bisamides stabilized by a
flexible bridged bis(phenolato) ligand and the high activity for the
polymerization of L-lactide. Chem. Commun. 2009, 47, 7414−7416.
(19) Lappert, M. F.; Pearce, R. Stable silylmethyl and neopentyl
complexes of scandium(III) and yttrium(III). J. Chem. Soc., Chem.
Commun. 1973, 4, 126.
(20) Taylor, M. D.; Carter, C. P. Preparation of Anhydrous
Lanthanide Halides, Especially Iodides. J. Inorg. Nucl. Chem. 1962, 24,
387−391.
(21) (a) Chen, H.; Bartlett, R. A.; Dias, H. V. R.; Olmstead, M. M.;
Power, P. P. Synthesis and Structural Characterization of Manganese-
(II) Derivatives of the Bulky, Chelating Bis(amido) Ligands
[(NMes)2SiMe2]2‑ and [DippNCH2CH2NDipp]2‑, Their Neutral
Amine Precursors, and Their Lithium Salts (Mes = 2,4,6-
Me3C6H2;Dipp = 2,6-i-Pr2C6H3). Inorg. Chem. 1991, 30, 2487−
2494. (b) Day, B. M.; Pugh, T.; Hendriks, D.; Guerra, C. F.; Evans, D.
J.; Bickelhaupt, F. M.; Layfield, R. A. Normal-to-Abnormal
̈
(f) Zimmermann, M.; Tonroos, K. W.; Anwander, R. Alkyl migration
and an unusual tetramethylaluminate coordination mode: Unexpected
reactivity of organolanthanide imino-amido-pyridine complexes.
Angew. Chem., Int. Ed. 2007, 46, 3126−3130. (g) Qian, C.; Zhu, D.
Studies on Organolanthanide Complexes.55. Synthesis of Furan-
Bridged Bis(cyclopentadienyl) lanthanide and Yttrium Chlorides, and
Ligand and Metal Tuning of Reactivity of Organolanthanide Hydrides
(in-situ). J. Chem. Soc., Dalton Trans. 1994, 10, 1599−1603.
̈
(h) Dreier, T.; Unger, G.; Erker, G.; Wibbeling, B.; Frohlich, R.
Group 4 metallocenes containing hetaryl substituents at their pi-
ligands: synthesis and characterization of the parent bis[2-(2-
G
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Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
Rearrangement and NHC Activation in Three-Coordinate Iron(II)
Carbene Complexes. J. Am. Chem. Soc. 2013, 135, 13338−13341.
(22) Sheldrick, G. M. SADABS: Program for Empirical Absorption
̈
̈
Correction of Area Detector Data; University of Gottingen: Gottingen,
Germany, 1996.
(23) (a) Sheldrick, G. M. SHELXTL 5.10 for Windows NT: Structure
Determination Software Programs; Bruker Analytical X-ray Systems,
Inc.: Madison, WI, 1997. (b) Sheldrick, G. M. SHELXT-Integrated
space-group and crystals-structure determination. Acta Crystallogr.,
Sect. A: Found. Adv. 2015, 71, 3−8. (c) Dolomanov, O. V. L.; Bourhis,
J. R.; Gildea, J.; Howard, J. A. K.; Puschmann, H. J. Appl. Crystallogr.
2009, 42, 339−341.
H
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Organometallics XXXX, XXX, XXX−XXX