Direct synthesis of NNN-donor enantiopure scorpionate ligands by an efficient diastereoselective nucleophilic addition to imines

Article abstract of DOI:10.1021/ic102242x

New enantiopure imines (1-9) with a chiral substrate to control the stereochemistry of a newly created stereogenic center have been synthesized by reaction of the commercially available (1R)-(-)-myrtenal and different primary amines. The diastereomericall

Full text of DOI:10.1021/ic102242x

1826 Inorg. Chem. 2011, 50, 1826–1839
DOI: 10.1021/ic102242x
Direct Synthesis of NNN-Donor Enantiopure Scorpionate Ligands by an Efficient
Diastereoselective Nucleophilic Addition to Imines
ꢀ
ꢀ
´
Antonio Otero,* Juan Fernandez-Baeza,* Juan Tejeda, Agustın Lara-Sanchez, Sonia Franco,
ꢀ
ꢀ
´
´
´
Jaime Martınez-Ferrer, Marıa P. Carrion, I. Lopez-Solera, and Ana M. Rodrıguez
´
ꢀ
ꢀ
´
Departamento de Quımica Inorganica, Organica y Bioquımica, Universidad de Castilla-La Mancha,
Campus Universitario, 13071-Ciudad Real, Spain
ꢀ
Luis F. Sanchez-Barba
´
ꢀ
´
Departamento de Quımica Inorganica y Analıtica, Universidad Rey Juan Carlos,
Mostoles-28933-Madrid, Spain
Received November 8, 2010
New enantiopure imines (1-9) with a chiral substrate to control the stereochemistry of a newly created stereogenic
center have been synthesized by reaction of the commercially available (1R)-(-)-myrtenal and different primary
amines. The diastereomerically enriched lithium-scorpionate compounds [Li(κ3-mbpza)(THF)] (10) (mbpza = N-p-
methylphenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethyl-
amide), [Li(κ3-mobpza)(THF)] (11) (mobpza = N-p-methoxyphenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-
2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), [Li(κ3-fbpza)(THF)] (12) (fbpza = N-p-fluorophenyl-(1R
and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), and [Li(κ3-
clbpza)(THF)] (13) (clbpza = N-p-chlorophenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-
bis(3,5-dimethylpyrazol-1-yl)ethylamide) were obtained by a diastereoselective 1,2-addition of an organolithium
reagent to imines in good yield and with good diastereomeric excess (ca. 80%). The complexes [LiCl(κ2-R,R-
fbpzaH)(THF)] (14) and [LiCl(κ2-R,R-clbpzaH)(THF)] (15) were obtained in enantiomerically pure form by the
treatment of THF solutions of 12 or 13 with NH4Cl. The enantiomerically pure amines (R,R-mbpzaH) (16), (R,R-
mobpzaH) (17), (R,R-fbpzaH) (18), and (R,R-clbpzaH) (19) were obtained by hydrolysis of the lithium-scorpionate
compounds 10-13 with H2O. The lithium compound 12 was reacted with [TiCl4(THF)2] or [ZrCl4] to give the
enantiopure complexes [MCl3(κ3-R,R-fbpza)] [M = Ti (20), Zr (21)]. The amine compound 18 reacted with [MX4] (M =
Ti, X = OiPr, OEt; M = Zr; X = NMe2) to give the complexes [MX3(κ3-R,R-fbpza)] (22-24). The reaction of Me3SiCl
with [Zr(NMe2)3(κ3-R,R-fbpza)] (24) in different molar ratios led to the halide-amide-containing complexes
[ZrCl(NMe2)2(κ3-R,R-fbpza)] (25) and [ZrCl2(NMe2)(κ3-R,R-fbpza)] (26) and the halide complex 21. The isolation
of only one of the three possible diastereoisomers of complexes 25 and 26 revealed that chiral induction from the ligand
1
to the zirconium center took place. The structures of these compounds were elucidated by H and 13C{1H} NMR
spectroscopy, and the X-ray crystal structures of 5, 12, 14, 15, and 24 were also established.
Introduction
with pyrazole rings.2 The synthesis of chiral ligands of high
enantiopurity is an important goal in organometallic chem-
istry in order to prepare metal-based reagents in efficient
asymmetric processes.3 Recently, we reported4 the preparation
In recent years, our research group has been interested in
the synthesis of enantiopure “heteroscorpionate” ligands1
*To whom correspondence should be addressed. E-mail: antonio.
otero@uclm.es (A.O.), juan.fbaeza@uclm.es (J.F.-B.).
(3) (a) Ojima, I. Catalytic Asymmetric Synthesis, 2nd ed.; Wiley-VCH: New
York, 2000. (b) Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H. Comprehensive
Asymmetric Catalysis; Springer: Berlin, 1999; vols. 1-3. (c) Noyori, R.;
Asymmetric Catalysis in Organic Synthesis; John Wiley & Sons: New York,
ꢀ
ꢀ
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(1) Otero, A.; Fernandez-Baeza, J.; Lara-Sanchez, A.; Tejeda J.; Sanchez-
Barba, L. F. Eur. J. Inorg. Chem. 2008, 5309-5326 (microreview).
(2) (a) Trofimenko, S. Scorpionates. The Coordination Chemistry of
Polypyrazolylborate Ligands; Imperial College Press: London, 1999. (b) Pettinari,
C. Scorpionates II: Chelating Borate Ligands; Imperial College Press: London,
ꢀ
ꢀ
1994. (d) Nogradi, M. Stereoselective Synthesis; VCH: Weinheim, Germany,
1995. (e) Organolithiums in Enantioselective Synthesis; Hodgson, D. M.
Springer: Heidelberg, 2003; Vol. 5. (f) Goldfuss, B. Synthesis 2005, 14, 2271–
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2008. (c) Otero, A.; Fernandez-Baeza, J.; Antinolo, A.; Tejeda, J.; Lara-Sanchez,
A. Dalton Trans. 2004, 1499-1510 (perspective article). (d) Pettinari, C.;
Pettinari, R. Coord. Chem. Rev. 2005, 249, 663–691.
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r
pubs.acs.org/IC
Published on Web 01/11/2011
2011 American Chemical Society

Article
Inorganic Chemistry, Vol. 50, No. 5, 2011 1827
of new chiral bis(pyrazol-1-yl)methane-based NNO-donor
scorpionate ligands in a single high-yielding step by the 1,2-
addition of organometallics to aldehydes to afford chiral
secondary alcohols.3 When this type of reaction was carried
out with an enantiopure aldehyde [(1R)-(-)-myrtenal] as a
possible chiral substrate to control the stereochemistry of a
newly created asymmetric center,5 we obtained an enantio-
pure scorpionate ligand in one step with high stereoselec-
tivity. The limited availability of commercial enantiopure
aldehydes—together with the interest in extending this simple
and efficient syntheticroute for thepreparation of othertypes
of enantiopure scorpionate ligands in one step—led us to
focus our attention on enantiopure imine compounds6 as
possible chiral substrates to control the stereochemistry of a
newly created asymmetric center. The development of a new
methodology for asymmetric reactions of organolithium
reagents constitutes a remarkable and fundamental area of
progress in recent synthetic organic chemistry; thus, asym-
metric nucleophilic 1,2-addition of organolithium reagents
to CdN double bonds provides a versatile method for
the preparation of chiral amines.4 Optically active amines are
abundantly present in biologically active compounds and are
also important chiral building blocks. Diastereoselective
addition of organolithium reagents to imines has been
achieved with the use of chiral auxiliaries or chiral ligands;
this strategy involves a diastereoselective reaction and se-
paration of the diastereomers. Takahashi and co-workers7
reported pioneering work on this strategy. Organolithium
reagents undergo addition to imines derived from aryl
aldehydes and valinol or phenylglycinol to give amines in
good yields and with high diastereoselectivity. The other
strategy involves the use of chiral ligands for the direct
introduction of chirality to an imine and/or an organolithium
reagent. For example, the addition of the lithium carbanion
of (R)-methyl p-tolyl sulfoxide to an imine afforded
β-sulfinylamine with high diastereoselectivity.8 Furthermore,
when the imine is R,β-unsaturated, the enantioselective con-
jugate addition (or Michael reaction, 1,4-addition) and 1,2-
addition to CdN double bonds are powerful methods for
forming a carbon-carbon bond. The first prominent cata-
lytic asymmetric conjugate addition reaction of an organo-
lithium reagent was that between 1-naphthyllithium and a
naphthaldehyde imine under the control of a chiral diether,
Scheme 1. Synthesis of Enantiopure Imines 1-9
with only a catalytic amount of this chiral ether (5 mol %)
required to give binaphthyl in 82% ee.9 Tomioka and co-
workers10 also reported the stoichiometric and catalytic
asymmetric 1,2-addition of organolithium reagents to N-
arylimines mediated by an external chiral ligand. In this work,
we have developed and fully explored the potential offered by
an efficient synthetic route (enantioselective 1,2-addition to
CdN double bonds by an organolithium reagent controlled
by a chiral auxiliary) to obtain a new type of enantiopure
NNN-donor scorpionate ligand. In order to achieve this type
of reaction, we synthesized new enantiopure imines with a
chiral substrate to control the stereochemistry of a newly
created asymmetric center, and subsequently we obtained an
enantiopure scorpionate ligand in one step with high stereo-
selectivity. Furthermore, the lithium amide-scorpionate or
amine-scorpionate compounds were found to be excellent
reagents for the introduction of scorpionate ligands into
group 4 metal complexes, and a series of neutral chloride,
amide, and alkoxide complexes were prepared by the treat-
ment of MCl4, M(NMe2)4, orM(OR)4 with these lithium- or
amine-scorpionate compounds. In addition, we corrobo-
rated the chiral induction from these scorpionate ligands to
the metal center in the amide-halide exchange process of
ligands in the coordination sphere.
Results and Discussion
The strategy employed in the initial phase of this work led
us to synthesize new enantiopure imines with a chiral sub-
strate to control the stereochemistry of a newly created
asymmetric center. Thus, the reaction of the commercially
available (1R)-(-)-myrtenal and different primary amines,
such as isopropylamine, p-methylaniline, p-methoxyaniline,
p-fluoroaniline, o-fluoroaniline, m-fluoroaniline, p-chloroani-
line, o-chloroaniline, and o-bromoaniline, gave new enantio-
pure imines 1-9, which were all R,β-unsaturated. These imines
were obtained as red solids in good yields (ca. 90%; Scheme 1).
The 1H NMR spectra of 1-9 exhibit five sets of resonances
for Hb, Hd, He, Hf, and geminal-Hh and three singlets for Ha
and the methyl groups of the bicyclic moiety. In addition, the
spectra show the corresponding signals for the alkyl or aryl
substituent on the nitrogen atom. 1H-13C heteronuclear
ꢀ
~
(4) (a) Otero, A.; Fernandez-Baeza, J.; Antinolo, A.; Tejeda, J.; Lara-
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Sanchez, A.; Sanchez-Barba, L.; Sanchez-Molina, M.; Franco, S.; Lopez-
Solera, M. I.; Rodrıguez, A. M. Inorg. Chem. 2007, 46, 8475–8477. (b) Otero,
´
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A.; Fernandez-Baeza, J.; Tejeda, J.; Lara-Sanchez, A.; Sanchez-Molina, M.;
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Franco, S.; Lopez-Solera, M. I.; Rodríguez, A. M.; Sanchez-Barba, L. F.;
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Morante-Zarcero, S.; Garces, A. Inorg. Chem. 2009, 48, 5540–5554.
(5) See, for example: (a) Martinez-Ramos, F.; Vargas-Dı
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Chacon-Garcı
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a, L.; Tamariz, J.; Joseph-Nathan, P.; Zepeda, L. G. Tetra-
hedron: Asymmetry 2001, 12, 3095–3103. (b) Vargas-Díaz, M. E.; Lagunas-
Rivera, S.; Joseph-Nathan, P.; Tamariz, J.; Zepeda, L. G. Tetrahedron Lett. 2005,
46, 3297–3300. (c) Vargas-Díaz, M. E.; Joseph-Nathan, P.; Tamariz, J.; Zepeda,
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L. G. Org. Lett. 2007, 9, 13–16. (d) Alvaro, E.; de la Torre, M. C.; Sierra, M. A.
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Chem. Commun. 2006, 985–987. (e) Silva, M. M. C.; Sae Melo, M. L.; Parolin,
M.; Tessaro, D.; Riva, S.; Danieli, B. Tetrahedron: Asymmetry 2004, 15, 21–27.
(f) Fleming, F. F.; Shook, B. C. J. Org. Chem. 2002, 67, 3668–3672.
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(6) Angermund, K.; Eckerle, A.; Monkiewicz, J.; Kruger, C.; Wilke, G.
(9) Shindo, M.; Koga, K.; Tomioka, K. J. Am. Chem. Soc. 1992, 114,
8732–8733.
Inorg. Chim. Acta 1998, 273–278.
(7) (a) Takahashi, H.; Suzuki, Y.; Inagaki, H. Chem. Pharm. Bull. 1982,
30, 3160–3166. (b) Takahashi, H.; Suzuki, Y.; Hori, T. Chem. Pharm. Bull. 1983,
31, 2183–2191. (c) Suzuki, Y.; Takahashi, H. Chem. Pharm. Bull. 1983, 31,
2895–2898.
(10) (a) Tomioka, K.; Inoue, I.; Shindo, M.; Koga, K. Tetrahedron Lett.
1990, 31, 6681–6684. (b) Tomioka, K.; Inoue, I.; Shindo, M.; Koga, K.
Tetrahedron Lett. 1991, 32, 3095–3098. (c) Inoue, I.; Shindo, M.; Koga, K.;
Tomioka, K. Tetrahedron 1994, 50, 4429–4438. (d) Inoue, I.; Shindo, M.; Koga,
K.; Tomioka, K. Tetrahedron: Asymmetry 1993, 4, 1603–1606.
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36, 3389–3392.

1828 Inorganic Chemistry, Vol. 50, No. 5, 2011
Otero et al.
Table 1. Results of Selective Nucleophilic 1,2-Addition of “Lithium Bis(3,5-
dimethylpyrazol-1-yl)methide” to R,β-Unsaturated Imines (1-9)
imine
R
complex
yield %
%R,R
de%a
1
2
3
4
5
6
7
8
9
iPr
p-MeC6H4
p-OMeC6H4
p-FC6H4
10
11
12
70
75
90
81
75
89
62
50
78
o-FC6H4
m-FC6H4
p-ClC6H4
o-ClC6H4
o-BrC6H4
13
90
93
86
a Diastereomeric excess (de%) has been calculated as the diference
between %RR and %RS.
Reaction of the R,β-unsaturated imines bearing an aryl
group on the imine nitrogen atom (2-9) results in selective
1,2-addition and not Michael-type conjugate addition. The
N-aryl substituent in the starting imines has a profound effect
on diastereoselectivities. This effect is particularly marked
in the addition to the imines bearing p-fluorophenyl or
p-chlorophenyl groups (4 and 7), where good diastereoselec-
tivities were obtained. However, N-alkyl (1), o-aryl (5, 8, and
9), or m-aryl (6) substituents in the imines have a detrimental
effect because the nucleophilic 1,2-addition of organolithium
reagents to CdN double bonds does not take place (the
starting materials were recovered). This situation is probably
due to steric factors in the case of the N-o-aryl substitution in
the imines and the lack of stabilization of the anionic amide
species in the N-alkylimine (1). The result obtained with the
meta substituted imine 6 is not yet understood.
Figure 1. ORTEP view of imine 5. Ellipsoids are at the 30% probability
level.
correlation (g-HSQC) experiments were carried out and al-
lowed us to assign the resonances corresponding to the 13C-
{1H} NMR spectra of these compounds. The molecular struc-
ture of 5 was determined by X-ray diffraction (Figure 1). Sig-
nificant bond lengths and angles are presented in Table 2. The
C(10)-N(1) distance in this compound [1.282(5) A] is typical
of CdN double bonds found in Schiff bases (ca. 1.26 A) or the
amidine-scorpionate derivative [1.275(3) A].11 The C(7)-
C(8) distance of 1.331(5) A corresponds to the CdC double
bond of the bicyclic moiety bound to the nitrogen atom to form
an R,β-unsaturated imine. The essentially sp2 and planar
nature of the R,β-unsaturated imine was further confirmed
by the angles C(8)-C(7)-C(10) of 121.3(4)°, N(1)-C(10)-
C(7) of 122.6(4)°, and C(10)-N(1)-C(11) of 118.0(3)°.
Once the new enantiopure imines had been synthesized, we
focused our attention on the preparation of enantiopure
scorpionate ligands by asymmetric nucleophilic 1,2-addition
of organolithium reagents to CdN double bonds. Thus, a
cold (-10 °C) THF solution of lithium bis(3,5-dimethylpyr-
azol-1-yl)methide, prepared in situ from BunLi and bis(3,5-
dimethylpyrazol-1-yl)methane at -70 °C, was added to a
THF solution containing 1 equiv of the corresponding imines
1-9 (Table 1). After the appropriate workup, the diaster-
eomerically enriched lithium-scorpionate compounds [Li(κ3-
mbpza)(THF)] (10) (mbpza = N-p-methylphenyl-(1R and
1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis-
(3,5-dimethylpyrazol-1-yl)ethylamide), [Li(κ3-mobpza)(THF)]
(11) (mobpza = N-p-methoxyphenyl-(1R and 1S)-1-[(1R)-
6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethyl-
pyrazol-1-yl)ethylamide), [Li(κ3-fbpza)(THF)] (12) (fbpza=
N-p-fluorophenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo-
[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethyl-
amide), and [Li(κ3-clbpza)(THF)] (13) (clbpza=N-p-chloro-
phenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-
hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide)
were obtained as brown or red solids in good yield and with
good to moderate diastereomeric excess (Scheme 2).
Initial evidence for the stereochemical route was obtained
from the X-ray molecular structures of a diverse range of
synthesized compounds. These structures had the R config-
uration for the newly formed chiral center in the major
diastereoisomer (see below). This finding indicates that the
diastereofacial attack of the nucleophile had proceeded at the
Si face of the imine group in an S-trans conformation. The
steric effect of one of the methyl groups of the bicyclic moiety
is probably the main driving force for the diastereoselectivity
observed in the process (Figure 2). The diastereoselectivity
1
was assessed by considering the H NMR spectrum and
integrating the CHa or Me signals of the bicycle in the crude
reaction mixture, since the signals for these protons appear at
a higher field for the S epimer.
Having obtained these new chiral heteroscorpionate li-
gands in the form of the lithium compounds, we attempted
the protonolysis of the Li-N bond to obtain the correspond-
ing amines. Treatment of the THF solutions of 12 or 13 with
NH4Cl (saturated solution) afforded the amines, but these
were coordinatedto “LiCl” by the nitrogen atomsof pyrazole
rings. The complexes [LiCl(κ2-R,R-fbpzaH)(THF)] (14) and
[LiCl(κ2-R,R-clbpzaH)(THF)] (15) were obtained in enan-
tiomerically pure form by crystallization from CH2Cl2/n-
hexane as red solids in good yield (ca. 70%) (see Scheme 3).
In view of the difficulty in obtaining the free amines by
reaction with ammonium chloride, we attempted the hydro-
lysis by treatment of THF solutions of lithium-scorpionate
compounds (10-13) with H2O. Thus, the amine compounds
(R,R-mbpzaH) (16), (R,R-mobpzaH) (17), (R,R-fbpzaH)
(18), and (R,R-clbpzaH) (19) were obtained in enantiomeri-
cally pure form by crystallization from CH2Cl2/n-hexane as
red or orange solids in good yield (ca. 70%; see Scheme 4).
ꢀ
~
(11) Otero, A.; Fernandez-Baeza, J.; Antinolo, A.; Tejeda, J.; Lara-
ꢀ
ꢀ
Sanchez, A.; Sanchez-Barba, L.; Lopez-Solera, M. I.; Rodrı
´
guez, A. M.
Inorg. Chem. 2007, 46, 1760–1770.

Article
Inorganic Chemistry, Vol. 50, No. 5, 2011 1829
Scheme 2. Synthesis of Lithium-Scorpionate Compounds 10-13
Scheme 3. Synthesis of Lithium-Amine Complexes 14 and 15
Scheme 4. Synthesis of Amine-Scorpionate Compounds 16-19
Figure 2. Diastereofacial attack of the nucleophile.
Two sets of 1H and13C{1H} NMR signals were observed in
the spectra of lithium complexes 10-13, a finding that is
consistent with the presence of two diastereoisomers (major
and minor; see Figure 3). These spectra contain two singlets
for each of the H4, Me3, and Me5 pyrazole protons in both
diastereoisomers, indicating that the two pyrazole rings are
from CH2Cl2/n-hexane. The ORTEP diagram for compound
12 is shown in Figure 4. Significant bond distances and bond
angles are listed in Table 2. The geometry around the Li atom
can be described as a distorted tetrahedron. This distortion is
due to the heteroscorpionate ligand, which acts in a κ3-NNN-
coordination mode with N(5)-Li(1)-N(1), N(5)-Li(1)-N-
(3), and N(1)-Li(1)-N(3) angles of 91.6(8)°, 95.1(7)°, and
95.8(9)°, respectively, and O(1)-Li(1)-N(5), O(1)-Li(1)-
N(1), and O(1)-Li(1)-N(3) angles of 141.1(1)°, 115(1)°, and
1
inequivalent. Furthermore, the H NMR spectra show the
signals for the bicyclic moiety bound at the methylene bridge
and also those for the aryl substituent on the nitrogen atom.
Crystals suitable for X-ray diffraction of the (RR þ RS)
lithium-scorpionate 12 were obtained by crystallization

1830 Inorganic Chemistry, Vol. 50, No. 5, 2011
Otero et al.
Table 2. Bond Lengths [A] and Angles [deg] for 5 and 12
5
12
RR
RS
C(11)-N(1)
1.413(5)
1.434(5)
1.504(5)
1.282(5)
1.331(5)
1.362(4)
Li(1)-O(1)
1.95(2)
2.05(2)
2.04(2)
1.99(2)
1.43(1)
1.42(1)
1.47(1)
1.59(1)
1.51(1)
1.31(1)
1.49(1)
Li(2)-O(2)
1.96(2)
2.05(2)
2.10(2)
1.96(2)
1.48(1)
1.47(1)
1.43(1)
1.53(1)
1.55(1)
1.31(1)
1.49(1)
137(1)
111.7(9)
116.4(8)
96.6(7)
92.5(8)
93.4(8)
115.9(8)
129.4(8)
113.5(8)
108.5(8)
113.6(8)
112.7(8)
117.4(8)
113.1(8)
108.3(7)
C(7)-C(10)
N(1)-Li(1)
N(6)-Li(2)
C(7)-C(6)
N(3)-Li(1)
N(8)-Li(2)
C(10)-N(1)
N(5)-Li(1)
N(10)-Li(2)
C(7)-C(8)
N(2)-C(11)
N(9)-C(42)
C(12)-F(1)
N(4)-C(11)
N(7)-C(42)
N(1)-C(10)-C(7)
C(10)-N(1)-C(11)
C(8)-C(7)-C(10)
N(1)-C(10)-C(7)
C(10)-N(1)-C(11)
122.6(4)
N(5)-C(12)
N(10)-C(43)
C(42)-C(43)
118.0(3)
121.3(4)
122.6(4)
118.0(3)
C(11)-C(12)
C(12)-C(13)
C(13)-C(14)
C(13)-C(18)
O(1)-Li(1)-N(5)
O(1)-Li(1)-N(3)
O(1)-Li(1)-N(1)
N(5)-Li(1)-N(3)
N(5)-Li(1)-N(1)
N(3)-Li(1)-N(1)
C(43)-C(44)
C(44)-C(45)
C(44)-C(49)
141(1)
109(1)
115(1)
N(10)-Li(2)-O(2)
O(2)-Li(2)-N(6)
O(2)-Li(2)-N(8)
N(10)-Li(2)-N(6)
N(10)-Li(2)-N(8)
N(6)-Li(2)-N(8)
95.1(7)
91.6(8)
95.8(9)
114.6(8)
131.2(8)
113.4(9)
113.1(9)
115.3(8)
110.5(9)
115.8(8)
108.5(8)
110.0(9)
C(22)-N(5)-C(12)
C(22)-N(5)-Li(1)
C(12)-N(5)-Li(1)
N(4)-C(11)-N(2)
N(4)-C(11)-C(12)
N(2)-C(11)-C(12)
N(5)-C(12)-C(13)
N(5)-C(12)-C(11)
C(13)-C(12)-C(11)
C(53)-N(10)-C(43)
C(53)-N(10)-Li(2)
C(43)-N(10)-Li(2)
N(7)-C(42)-N(9)
N(7)-C(42)-C(43)
N(9)-C(42)-C(43)
N(10)-C(43)-C(44)
N(10)-C(43)-C(42)
C(42)-C(43)-C(44)
Figure 3. 1H NMR spectrum of complex 12.
Figure 4. ORTEP view of the (R,R) diastereoisomer of complex 12.
Ellipsoids are at the 30% probability level.
109(1)°, respectively. The Li-N distances 2.05(2) and 2.04(2)
A in the bis(pyrazol-1-yl)methane moiety are in good agree-
ment with others determined for lithium scorpionate or
bis(pyrazol-1-yl)methane complexes.12 The solid-state struc-
ture of this compound confirms that the amide is coordinated
to the Li atom. The N-Li bond length [1.99(2) A] is con-
sistent with that reported for the only previously known
amide13 or monodentate amidinate lithium compounds.11,14
The 1H and 13C{1H} NMR spectra of 14-19 each exhibit
one set of signals, a finding consistent with the presence of
ꢀ
~
(12) (a) Otero, A.; Fernandez-Baeza, J.; Tejeda, J.; Antinolo, A.; Carrillo-
ꢀ ꢀ ꢀ
´
Hermosilla, F.; Dıez-Barra, E.; Lara-Sanchez, A.; Fernandez-Lopez, M.;
1
one diastereoisomer (see Figure 5). In addition, in the H
Lanfranchi, M.; Pellinghelli, M. A. J. Chem. Soc., Dalton Trans. 1999, 3537–
ꢀ
~
ꢀ
3539. (b) Otero, A.; Fernandez-Baeza, J.; Antinolo, A.; Tejeda, J.; Lara-Sanchez,
NMR spectra, the signal for the NH group of the amine is
present between 8.50 and 11.70 ppm. As mentioned above,
the absolute configuration of these entatiomerically pure
compounds (14-19) and probably the one proposed for
ꢀ
A.; Sanchez-Barba, L.; Rodríguez, A. M.; Maestro, M. A. J. Am. Chem. Soc.
2004, 126, 1330–1331. (c) Otero, A.; Fernandez-Baeza, J.; Antinolo, A.; Tejeda,
J.; Lara-Sanchez, A.; Sanchez-Barba, L.; Sanchez-Molina, M.; Franco, S.; Lopez-
Solera, I.; Rodríguez, A. M. Eur. J. Inorg. Chem. 2006, 707–710. (d) Otero, A.;
ꢀ
~
ꢀ
ꢀ
ꢀ
~
ꢀ
ꢀ
Fernandez-Baeza, J.; Antinolo, A.; Tejeda, J.; Lara-Sanchez, A.; Sanchez-Barba,
L.; Sanchez-Molina, M.; Franco, S.; Lopez-Solera, I.; Rodríguez, A. M. Dalton
Trans. 2006, 4359–4370. (e) Reger, D. L.; Collins, J. E.; Matthews, M. A.;
Rheingold, A. L.; Liable-Sands, M.; Guzei, I. A. Inorg. Chem. 1997, 36, 6266–
6269.
(13) Adhikari, D.; Zhao, G.; Basuli, F.; Tomaszewski, J.; Huffman, J. C.;
Mindiola, D. J. Inorg. Chem. 2006, 45, 1604–1610.
(14) (a) Schmidt, J. A. R.; Arnold, J. Chem. Commun. 1999, 2149–2150.
(b) Schmidt, J. A. R.; Arnold, J. J. Chem. Soc., Dalton Trans. 2002, 2890–2899.

Article
Inorganic Chemistry, Vol. 50, No. 5, 2011 1831
Figure 5. 1H NMR spectrum of [LiCl(κ2-R,R-fbpzaH)(THF)] (14).
Figure 7. ORTEP view of [LiCl(κ2-R,R-clbpzaH)(THF)] (15). Ellip-
soids are at the 30% probability level, and hydrogen atoms have been
omitted for clarity.
Figure 6. ORTEP view of [LiCl(κ2-R,R-fbpzaH)(THF)] (14). Ellipsoids
are at the 30% probability level, and hydrogen atoms have been omitted
for clarity.
the major diastereoisomer of the lithium-scorpionate (10-
13) was verified by single crystal X-ray diffraction analyses
on compounds 14 and 15 (Figures 6 and 7) to have the R
configuration at Ca (C12). Selected bond lengths and angles
are listed in Table 3. In both complexes, the geometry around
the Li atom can be described as a distorted tetrahedron with
an amide-scorpionate ligand that acts in a bidentate fashion
(two coordinated pyrazole rings) and one molecule of THF
and chloride. Both Li-N distances [2.090(10) and 2.088(10)
A for 14 and 2.096(12) and 2.088(12) A for 15] are in good
agreement with others determined for lithium scorpionate or
poly(pyrazolyl)methane complexes.13
Having prepared these new heteroscorpionate ligands in
the form of the lithium or amine compounds, we explored
their potential utility as tridentate ligands in the preparation
of group 4 metal complexes. The lithium compound 12 was
reacted at -70 °C with [TiCl4(THF)2] or [ZrCl4] in a 1:1
molar ratio in THF to give, after the appropriate workup, the
enantiopure complexes [MCl3(κ3-R,R-fbpza)] [M = Ti (20),
Figure 8. ORTEP view of the complex [Zr(NMe2)3(κ3-R,R-fbpza)] (24).
Ellipsoids are atthe 30% probabilitylevel, and hydrogenatoms have been
omitted for clarity.

1832 Inorganic Chemistry, Vol. 50, No. 5, 2011
Otero et al.
Table 3. Bond Lengths [A] and Angles [deg] for 14, 15, and 24
14
15
24
Li(1)-O(1)
1.942(9)
2.090(10)
2.088(10)
2.255(9)
1.459(6)
1.388(6)
1.539(7)
1.500(7)
1.388(6)
N(1)-Li(1)
2.096(12)
2.088(12)
1.952(11)
2.254(11)
1.448(7)
1.395(7)
1.547(8)
1.514(8)
1.756(6)
Zr(1)-N(1)
2.423(6)
2.451(6)
2.235(6)
2.060(6)
2.075(6)
2.100(6)
1.481(8)
1.416(8)
1.544(9)
1.497(9)
110.7(5)
109.5(5)
116.3(6)
111.7(5)
114.5(6)
112.6(5)
108.0(6)
93.8(2)
100.8(2)
152.7(2)
167.9(2)
89.1(2)
84.0(2)
77.4(2)
93.8(2)
165.3(2)
79.9(2)
76.4(2)
Li(1)-N(1)
N(3)-Li(1)
Zr(1)-N(3)
Li(1)-N(3)
O(1)-Li(1)
Zr(1)-N(5)
Li(1)-Cl(1)
Cl(1)-Li(1)
Zr(1)-N(6)
C(12)-N(5)
C(12)-N(5)
Zr(1)-N(7)
C(22)-N(5)
C(22)-N(5)
Zr(1)-N(8)
C(11)-C(12)
C(11)-C(12)
N(5)-C(12)
C(12)-C(13)
C(12)-C(13)
N(5)-C(22)
C(25)-F(1)
C(25)-Cl(2)
C(11)-C(12)
N(2)-C(11)-N(4)
N(2)-C(11)-C(12)
N(4)-C(11)-C(12)
N(5)-C(12)-C(13)
N(5)-C(12)-C(11)
C(13)-C(12)-C(11)
C(22)-N(5)-C(12)
O(1)-Li(1)-N(3)
N(1)-Li(1)-N(3)
O(1)-Li(1)-Cl(1)
N(1)-Li(1)-Cl(1)
N(3)-Li(1)-Cl(1)
109.8(4)
N(4)-C(11)-N(2)
N(4)-C(11)-C(12)
N(2)-C(11)-C(12)
N(5)-C(12)-C(13)
N(5)-C(12)-C(11)
110.3(4)
C(12)-C(13)
112.1(4)
111.2(4)
112.6(4)
106.2(4)
112.8(4)
122.6(4)
103.1(4)
92.5(4)
111.2(4)
111.5(4)
113.1(4)
105.2(4)
112.1(4)
122.1(5)
104.9(5)
100.4(5)
92.7(5)
C(22)-N(5)-C(12)
N(2)-C(11)-N(4)
N(2)-C(11)-C(12)
N(4)-C(11)-C(12)
N(5)-C(12)-C(13)
N(5)-C(12)-C(11)
C(13)-C(12)-C(11)
C(22)-N(5)-C(12)
O(1)-Li(1)-N(3)
O(1)-Li(1)-N(1)
N(3)-Li(1)-N(1)
O(1)-Li(1)-Cl(1)
N(3)-Li(1)-Cl(1)
N(1)-Li(1)-Cl(1)
C(13)-C(12)-C(11)
N(6)-Zr(1)-N(5)
N(7)-Zr(1)-N(5)
N(8)-Zr(1)-N(5)
N(6)-Zr(1)-N(1)
N(7)-Zr(1)-N(1)
N(8)-Zr(1)-N(1)
N(5)-Zr(1)-N(1)
N(6)-Zr(1)-N(3)
N(7)-Zr(1)-N(3)
N(8)-Zr(1)-N(3)
N(5)-Zr(1)-N(3)
N(1)-Zr(1)-N(3)
115.0(4)
127.3(4)
115.0(4)
114.5(5)
114.9(5)
125.8(5)
76.2(2)
Scheme 5. Synthesis of Complexes [MCl3(κ3-R,R-fbpza)] (20-21)
Scheme 6. Synthesis of Complexes [MX3(κ3-R,R-fbpza)] (22-24)
Zr (21)], which were isolated by crystallization from CH2Cl2/
n-hexane as red and yellow solids, respectively, in moderate
yield (Scheme 5).
The amine compound 18 was reacted at room temperature
with [MX4] (M = Ti, X = OiPr, OEt; M = Zr; X = NMe2,)
in a 1:1 molar ratio in toluene to give, after the appropriate

Article
Inorganic Chemistry, Vol. 50, No. 5, 2011 1833
Figure 9. Proposed structures for the three possible diastereoisomers of complexes 25 and 26.
Scheme 7. Diastereoselective Amide-Halide Exchange Process (Synthesis of Complexes 25 and 26)
workup, the complexes [MX3(κ3-R,R-fbpza)] (22-24), which
were isolated as yellow solids in good yield (ca. 75%; Scheme6).
The 1H and 13C{1H} NMR spectra of 20-24 each exhibit
one set of signals, which is consistent with the presence of one
aryl substituent on the nitrogen atom. In addition, two
multiplets of signals corresponding to the OR ligands and
1
three singlets for the NMe2 ligands were observed. The H
NOESY-1D experiments enabled the unequivocal assign-
ment of all 1H resonances. The results are consistent with an
octahedral structure resulting from the κ3-NNN-coordina-
tion of the ligand to the metal center (Schemes 5 and 6). The
geometry found in solution was also confirmed in the solid
state by an X-ray structural analysis of complex 24 (Figure 8).
1
diastereoisomer. The H NMR spectra of these complexes
show two singlets for each of the H4, Me3, and Me5 pyrazole
protons, one singlet for each of the methine groups (CH
bridge of pyrazole rings and CHa), the signals for the bicyclic
moiety bound to the methylene bridge, and also those for the

1834 Inorganic Chemistry, Vol. 50, No. 5, 2011
Otero et al.
The scorpionate ligand retains the R-configuration for the Ca
(C12) atom. Selected bond lengths and angles are listed in
Table 3. The structure consists of a heteroscorpionate ligand
bonded to the zirconium atom through the two nitrogen
atoms of pyrazole rings and the nitrogen atom of the amide
group in a κ3-NNN-coordination mode. In addition, the
zirconium center is coordinated to three amide ligands. This
center has a distorted octahedral environment with a major
distortion in the N(8)-Zr(1)-N(5) angle and N(7)-Zr(1)-
N(3) angle, which have values of 152.7(2)° and 165.3(2)°,
respectively. The Zr(1)-N(1) and Zr(1)-N(3) bond dis-
tances of 2.423(6) A and 2.451(6) A, respectively, which are
longer than those in similar heteroscorpionate complexes,15
indicate that the amide ligands exert a trans influence.16 The
X-ray diffraction results confirm the presence in the solid
state of one diastereoisomer for this complex.
isolated. The configuration of 26 is consistent with chiral
induction from these scorpionate ligands to the metal center
in the amide-halide ligand exchange process in the coordi-
nation sphere. However, the configuration of monochlori-
nated complex (25) could result from the difference between
amide and pyrazole trans to the substituted ligand.15
Conclusions
In conclusion, we present a one-pot synthesis of new
enantiopure NNN-donor scorpionate ligands by a diaster-
eoselective nucleophilic 1,2-addition of organolithium re-
agents to CdN double bonds in imines, with control
provided by a chiral auxiliary. The reactions studied gave
good levels of diastereoselectivity. The potential offered by
this efficient synthetic route has been fully developed and
explored. In this respect, new enantiopure imines with a
chiral substrate to control the stereochemistry of a newly
created asymmetric center have been synthesized, and it was
verifed that the N-aryl substituent in the starting imines has a
profound effect on the enantioselectivity. The R,β-unsatu-
rated imines and, in particular, those bearing a very electro-
negative (F or Cl) substituent in the para position, led to
highly diastereoselective processes, with a preference for 1,2
addition over Michael-type conjugate addition. In the second
part of this work, we verified the potential utility of these
ligands as valuable scaffolds in organometallic/coordination
chemistry through the preparation of new enantiomerically
pure group 4 metal complexes in which the ligands behave in
a tridentate manner with a κ3-NNN coordination mode. Thus,
a series of neutral chloride, amide, and alkoxide complexes was
prepared by the treatment of MCl4, M(NMe2)4, or M(OR)4
with the lithium or amine-scorpionate compounds. In addi-
tion, the close proximity of the stereogenic carbon to the
metal, an arrangement that is able to create an effective chiral
pocket around the metal center, enabled us to corroborate
the chiral induction from these scorpionate ligands to the
metal center in the amide-halide ligand exchange process in
the coordination sphere.
Once it had been corroborated that these compounds were
excellent reagents for the introduction of scorpionate ligands
into group 4 metal complexes, and in view of the close
proximity of the stereogenic carbon Ca to the metal—an
arrangement that is able to create an effective chiral pocket
around the metal center—we thought it was opportune to
study the chiral induction from the scorpionate ligand to the
metal center in the ligand exchange process in the coordina-
tion sphere. The amide-halide exchange reaction is well
documented in group 4 metal amide complexes.3b,12d,17 The
reaction of Me3SiCl with [Zr(NMe2)3(κ3-R,R-fbpza)] (24) in
different molar ratios and under different experimental con-
ditions (see Experimental Section) led to the preparation of
the halide-amide-containing complexes [ZrCl(NMe2)2(κ3-
R,R-fbpza)] (25) and [ZrCl2(NMe2)(κ3-R,R-fbpza)] (26) and
the halide complex [ZrCl3(κ3-R,R-fbpza)] (21) (Scheme 7).
The latter complex could also be obtained by the reaction of
1
lithium compound 12 with ZrCl4 (Scheme 5). The H and
13C{1H} NMR spectra of 25 and 26 exhibit two distinct sets
1
of pyrazole resonances. The H NMR spectra contain two
singlets for the NMe2 moieties in complex 25 and a single
broad signal for the NMe2 moiety in complex 26. These
results are consistent with the presence of only one diaster-
eoisomer and also with the proposed octahedral arrangement
depicted in Scheme 7. Three isomers are possible for these
complexes—two with the chloride (25) or amide (26) ligand
trans to the nitrogen atoms of the pyrazolyl rings (Figure
9a-c or d,e) and another with the chloride (25) or amide (26)
ligand trans to the nitrogen of the amide of scorpionate ligand
(Figures 9c-f). In complex 25, the absence of a response in
the 1H NOESY-1D experiment from both sets of Me3
protons of the pyrazolyl rings on irradiating the methyl
groups of each NMe2 group suggests that the isomer in
which the chloride ligand is trans to the nitrogen amide
scorpionate ligand (isomer c) had been isolated. In complex
26, however, the response in the 1H NOESY-1D experiment
from the proton of the chiral carbon on irradiating the methyl
groups of NMe2 group suggests that isomer “d” had been
Experimental Section
All reactions were performed using standard Schlenk-tube
techniques under an atmosphere of dry nitrogen. Solvents
were distilled from appropriate drying agents and degassed
before use. Microanalyses were carried out with a Perkin-
Elmer 2400 CHN analyzer. 1H and 13C NMR spectra were
recorded on a Varian Inova FT-500 spectrometer and refe-
renced to the residual deuterated solvent. The NOESY-1D
spectra were recorded with the following acquisition para-
meters: an irradiation time of 2s and a number of scans of
256, using standard VARIAN-FT software. Two-dimen-
sional NMR spectra were acquired using standard VAR-
IAN-FT software and processed using an IPC-Sun com-
puter. Optical rotations were determined on a Jasco P-2000
polarimeter at the sodium D line using a quartz cell of 1.00
dm path length. The precursor compounds of titanium or
zirconium, (1R)-(-)-myrtenal, and the different primary
amines (isopropylamine, p-methylaniline, p-methoxyani-
line, p-fluoroaniline, o-fluoroaniline, m-fluoroaniline,
p-chloroaniline, o-chloroaniline and o-bromoaniline trime
thylacetaldehyde, and p-tolualdehyde) were purchased
(15) Milione, S.; Bertolasi, V.; Cuenca, T.; Grassi, A. Organometallics
2005, 24, 4915–4925.
(16) Coe, B. J.; Glenwright, S. J. Coord. Chem. Rev. 2000, 203, 5–80.
(17) (a) Benzing, E.; Kornicker, W. Chem. Ber. 1961, 94, 2263–2267.
(b) Wade, S. R.; Willey, G. R. J. Chem. Soc., Dalton Trans. 1981, 1264–1267.
(c) Diamond, G. M.; Jordan, R. F.; Petersen, J. L. J. Am. Chem. Soc. 1996, 118,
(18) (a) Sebastian, J.; Sala, P.; Del Mazo, J.; Sancho, M.; Ochoa, C.;
ꢀ
~
8024–8033. (d) Otero, A.; Fernandez-Baeza, J.; Antinolo, A.; Tejeda, J.;
Elguero, J.; Fayet, J. P.; Vertut, M. C. J. Heterocyclic Chem. 1982, 19, 1141–
ꢀ
ꢀ
ꢀ
Lara-Sanchez, A.; Sanchez-Barba, L.; Sanchez-Molina, M; Rodríguez, A. M.;
1145. (b) Díez-Barra, E.; de la Hoz, A.; Sanchez-Migallon, A.; Tejeda, J. J. Chem.
Bo, C.; Urbano-Cuadrado, M. Organometallics 2007, 26, 4310–4320.
Soc., Perkin Trans. 1 1993, 1079–1083.

Article
Inorganic Chemistry, Vol. 50, No. 5, 2011 1835
from Aldrich. The compound bdmpzm [bdmpzm = bis-
(3,5-dimethylpyrazol-1-yl)methane]18 was prepared as re-
ported previously.
K): δ 156.5 (Ca), 25.8 (Meg), 20.9 (Meg), 137.8 (Cd), 32.7 (Ce),
=
=
37.6 (Cg), 41.0(Cf), 40.0(Cb), 151.5(Cc), 31.3(Ch), 116.2 (d, JCF
19.8 Hz, m-C), 124.4 (d, JCF = 3.8 Hz, m-C), 155.5 (d, JCF
248.0 Hz, o-C), 122.4 (d, JCF=2.3 Hz, o-C), 126.0 (d, JCF =7.6
Hz, p-C), 149.6 (ipso-C).
Preparation of Imines 1-9. Synthesis of Imine 1. (1R)-(-)-
Myrtenal (1.00 g, 6.66 mmol) was added to isopropylamine (0.39 g,
6.66 mmol) in a 250 cm3 Schlenk tube, and the reaction mixture
was stirred and heated under reflux for 12 h. The reaction
mixture was cooled to room temperature and dissolved in dry
diethyl ether. The solution was dried over anhydrous MgSO4
and concentrated under reduced pressure to give imine 1 as a
red solid after crystallization from diethyl ether. Yield: 90%.
Synthesis of Imine 6. The synthetic procedure was the same as
for imine 3, using (1R)-(-)-myrtenal (1.00 g, 6.66 mmol) and m-
fluoroaniline (0.74 g, 6.66 mmol), to give imine 6 as a red solid.
Yield: 90%. [R]D25 -73.09 (c 1.00, THF). Anal. Calcd for C16-
H18FN: C, 79.01; H, 7.41; N, 5.76. Found: C, 79.20; H, 7.40; N,
5.79. 1H NMR (C6D6, 297 K): δ 7.88 (s, 1 H, CHa), 1.18 (s, 3 H,
Meg), 0.74 (s, 3 H, Meg), 5.80 (s, 1 H, Hd), 2.16 (m, 2 H, He), 1.89
(m, 1 H, Hf), 3.48 (m, 1 H, Hb), 2.32 (m, 1 H, Hh), 1.04 (d, 1 H,
Hh), 6.62-6.85 (m, 4 H, m,o,p-H). 13C-{1H} NMR (C6D6, 297
K): δ 156.4 (Ca), 25.8 (Meg), 20.9 (Meg), 137.3 (Cd), 32.7 (Ce),
25
[R]D þ21.4 (c 1.00, CH2Cl2). Anal. Calcd for C14H21N: C,
81.67; H, 11.00; N, 7.33. Found: C, 81.72; H, 11.11; N, 7.17. 1H
NMR (C6D6, 297 K): δ 7.74 (s, 1 H, CHa), 1.26 (s, 3 H, Meg),
0.71 (s, 3 H, Meg), 5.86 (s, 1 H, Hd), 2.36 (m, 2 H, He), 2.06 (m, 1
H, Hf), 2.89 (m, 1 H, Hb), 2.34 (d, 1 H, Hh), 1.04 (d, 1 H, Hh), 3.26
(m, 1 H, CHMe2), 1.08 (m, 6 H, CHMe2). 13C-{1H} NMR
(C6D6, 297 K): δ 159.5 (Ca), 26.1 (Meg), 21.0 (Meg), 133.5 (Cd),
32.5 (Ce), 37.8 (Cg), 41.2 (Cf), 40.2 (Cb), 148.6 (Cc), 31.6 (Ch),
61.5 (CHMe2), 24.5-24.4 (CHMe2).
37.6 (Cg), 41.1(Cf), 40.2(Cb), 150.5(Cc), 31.4(Ch), 126.1 (d, JCF
7.4 Hz, m-C), 157.2 (d, JCF = 245.3 Hz, m-C), 115.3 (d, JCF
=
=
20.2 Hz, o-C), 121.4 (d, JCF = 3.8 Hz, o-C), 119.3 (d, JCF = 20.2
Hz, p-C), 148.3 (ipso-C).
Synthesis of Imine 7. The synthetic procedure was the same as
for imine 3, using (1R)-(-)-myrtenal (1.00 g, 6.66 mmol) and p-
chloroaniline (0.82 g, 6.66 mmol), to give imine 7 as a red solid.
Yield: 91%. [R]D25 -54.02 (c 1.00, THF). Anal. Calcd for C16-
H18ClN: C, 74.00; H, 6.94; N, 5.40. Found: C, 74.13; H, 6.98; N,
5.38. 1H NMR (C6D6, 297 K): δ 7.68 (s, 1 H, CHa), 1.19 (s, 3 H,
Meg), 0.73 (s, 3 H, Meg), 5.80 (s, 1 H, Hd), 2.16 (m, 2 H, He), 1.90
(m, 1 H, Hf), 3.41 (m, 1 H, Hb), 2.33 (m, 1 H, Hh), 1.05 (d, 1 H,
Hh), 7.01 (d, 2 H, m-H), 6.77 (d, 2 H, o-H). 13C-{1H} NMR
(C6D6, 297 K): δ 160.5 (Ca), 25.9 (Meg), 21.0 (Meg), 137.4 (Cd),
32.8 (Ce), 37.6 (Cg), 41.0 (Cf), 40.2 (Cb), 149.4 (Cc), 31.4 (Ch),
129.2 (m-C), 122.5 (o-C), 131.0 (p-C), 151.3 (ipso-C).
Synthesis of Imine 2. The synthetic procedure was the same as
for imine 1, using (1R)-(-)-myrtenal (1.00 g, 6.66 mmol) and
p-methylaniline (0.71 g, 6.66 mmol), to give imine 2 as a red
25
solid. Yield: 90%. [R]D þ25.3 (c 1.00, CH2Cl2). Anal. Calcd for
C17H21N: C, 85.35; H, 8.79; N, 5.86. Found: C, 85.38; H, 8.75;
N, 5.87. 1H NMR (C6D6, 297 K): δ 8.04 (s, 1 H, CHa), 1.41 (s, 3
H, Meg), 0.87 (s, 3 H, Meg), 6.24 (s, 1 H, Hd), 2.53 (m, 2 H, He),
2.21 (m, 1 H, Hf), 3.21 (m, 1 H, Hb), 2.54 (m, 1 H, Hh), 1.21 (d,
1 H, Hh), 2.35 (s, 3 H, MePh), 7.15 (d, 2 H, m-H), 7.05 (d, 2 H,
o-H). 13C-{1H} NMR (C6D6, 297 K): δ 160.7 (Ca), 26.2 (Meg),
21.2 (Meg), 137.5 (Cd), 33.0 (Ce), 37.9 (Cg), 41.1 (Cf), 40.2 (Cb),
149.2 (Cc), 31.6 (Ch), 21.3 (MePh), 129.8 (m-C), 121.1 (o-C),
135.3 (p-C), 150.2 (ipso-C).
Synthesis of Imine 8. The synthetic procedure was the same as
for imine 3, using (1R)-(-)-myrtenal (1.00 g, 6.66 mmol) and
o-chloroaniline (0.82 g, 6.66 mmol), to give imine 8 as a red solid.
Synthesis of Imine 3. The synthetic procedure was the same as
for imine 1, using (1R)-(-)-myrtenal (1.00 g, 6.66 mmol) and p-
methoxyaniline (0.82 g, 6.66 mmol), to give imine 3 as a red
25
Yield: 83%. [R]D -49.98 (c 1.00, THF). Anal. Calcd for
C16H18ClN: C, 74.00; H, 6.94; N, 5.40. Found: C, 74.11; H,
6.86; N, 5.30. 1H NMR (C6D6, 297 K): δ 7.63 (s, 1 H, CHa), 1.18
(s, 3 H, Meg), 0.76 (s, 3 H, Meg), 5.78 (s, 1 H, Hd), 2.13 (m, 2 H,
He), 2.87 (m, 1 H, Hf), 3.45 (m, 1 H, Hb), 2.38 (m, 1 H, Hh), 1.04
(d, 1 H, Hh), 6.62-6.82 (m, 4 H, m,o,p-H). 13C-{1H} NMR
(C6D6, 297 K): δ 157.5 (Ca), 25.9 (Meg), 20.9 (Meg), 137.3 (Cd),
32.8 (Ce), 37.6 (Cg), 41.0 (Cf), 40.1 (Cb), 149.4 (Cc), 31.3 (Ch),
122.1-126.3 (m,o,p-C), 162.8 (o-C), 149.5 (ipso-C).
25
solid. Yield: 89%. [R]D þ33.2 (c 1.00, CH2Cl2). Anal. Calcd for
C17H21NO: C, 84.58; H, 9.25; N, 6.17. Found: C, 84.60; H, 9.21;
N, 6.19. 1H NMR (C6D6, 297 K): δ 7.98 (s, 1 H, CHa), 1.24 (s,
3 H, Meg), 0.80 (s, 3 H, Meg), 5.81 (s, 1 H, Hd), 2.20 (m, 2 H, He),
1.98 (m, 1 H, Hf), 3.61 (m, 1 H, Hb), 2.39 (m, 1 H, Hh), 1.14 (d,
1 H, Hh), 3.26 (s, 3 H, Me), 6.72-7.15 (m, 4H, m-H or o-H).
13C-{1H} NMR (C6D6, 297 K): δ 158.2 (Ca), 26.0 (Meg), 21.1
(Meg), 135.4 (Cd), 32.7 (Ce), 37.6 (Cg), 41.2 (Cf), 40.3 (Cb), 149.7
(Cc), 31.5 (Ch), 54.8 (OMe), 114.5-122.5 (m-C or o-C), 145.7
(p-C), 158.4 (ipso-C).
Synthesis of Imine 9. The synthetic procedure was the same as
for imine 3, using (1R)-(-)-myrtenal (1.00 g, 6.66 mmol) and o-
bromoaniline (1.15 g, 6.66 mmol), to give imine 9 as a red solid.
25
Synthesis of Imine 4. The synthetic procedure was the same as
for imine 3, using (1R)-(-)-myrtenal (1.00 g, 6.66 mmol) and
p-fluoroaniline (0.74 g, 6.66 mmol), to give imine 4 as a red solid.
Yield: 90%. [R]D -50.23 (c 1.00, THF). Anal. Calcd for
C16H18BrN: C, 63.18; H, 5.92; N, 4.60. Found: C, 63.21; H,
5.96; N, 4.18. 1H NMR (C6D6, 297 K): δ 7.61 (s, 1 H, CHa), 1.18
(s, 3 H, Meg), 0.72 (s, 3 H, Meg), 5.77 (s, 1 H, Hd), 2.16 (m, 2 H,
He), 1.89 (m, 1 H, Hf), 3.36 (m, 1 H, Hb), 2.32 (m, 1 H, Hh), 1.02
(d, 1 H, Hh), 6.73-7.05 (m, 4 H, m,o,p-H). 13C-{1H} NMR
(C6D6, 297 K): δ 158.4 (Ca), 26.1 (Meg), 21.2 (Meg), 138.0 (Cd),
32.9 (Ce), 37.8 (Cg), 41.6 (Cf), 40.6 (Cb), 151.7 (Cc), 31.6 (Ch),
123.4-127.3 (m,o,p-C), 162.9 (o-C), 149.6 (ipso-C).
25
Yield: 90%. [R]D -51.83 (c 1.00, THF). Anal. Calcd for
C16H18FN: C, 79.01; H, 7.41; N, 5.76. Found: C, 79.15; H,
7.43; N, 5.78. 1H NMR (C6D6, 297 K): δ 7.73 (s, 1 H, CHa), 1.19
(s, 3 H, Meg), 0.74 (s, 3 H, Meg), 5.81 (s, 1 H, Hd), 2.16 (m, 2 H,
He), 1.91 (m, 1 H, Hf), 3.43 (m, 1 H, Hb), 2.34 (m, 1 H, Hh), 1.06
(d, 1 H, Hh), 6.85 (t, 2 H, JHH = JHF = 8.3 Hz, m-H), 6.73 (dd,
2 H, JHH = 8.8 Hz, JHF = 4.9 Hz, o-H). 13C-{1H} NMR (C6D6,
297 K): δ 160.2 (Ca), 25.9 (Meg), 21.0 (Meg), 136.9 (Cd), 32.7
(Ce), 37.6 (Cg), 41.1 (Cf), 40.2 (Cb), 149.5 (Cc), 31.4 (Ch), 115.7
(d, JCF = 22.1 Hz, m-C), 122.5 (d, JCF = 7.6 Hz, o-C), 161.2
(d, JCF = 243.4 Hz, p-C), 148.8 (ipso-C).
Preparation of Scorpionate Ligands 10-19. Synthesis of
[Li(K3-mbpza)(THF)] (10). In a 250 cm3 Schlenk tube, bdmpzm
(1.00 g, 4.89 mmol) was dissolved in dry THF (70 cm3) and
cooled to -70 °C. A 1.6 M solution of BunLi (3.06 cm3, 4.89
mmol) in hexane was added, and the suspension was stirred for
1 h. The reaction mixture was warmed to -10 °C, and the resul-
ting yellow suspension was treated with a solution of imine 2
(1.17 g, 4.89 mmol) in dry THF (20 cm3), after which the solution
was stirred for 30 min. The reaction mixture was warmed to
room temperature and was stirred for 1 h. The solvent was remo-
ved to give a volume of 10 cm3, and the addition of hexane
(70 cm3) gave a brown solid. The solid was filtered off (Celite)
and dried under reduced pressure to give compound 10. The
yield was 70%, and the diastereomeric excess was 62% (de).
Synthesis of Imine 5. The synthetic procedure was the same as
for imine 3, using (1R)-(-)-myrtenal (1.00 g, 6.66 mmol) and
o-fluoroaniline (0.74 g, 6.66 mmol), to give imine 5 as a red solid.
Yield: 85%. [R]D25 -37.10 (c 1.00, THF). Anal. Calcd for C16-
H18FN: C, 79.01; H, 7.41; N, 5.76. Found: C, 78.85; H, 7.46; N,
5.81. 1H NMR (C6D6, 297 K): δ 7.68 (s, 1 H, CHa), 1.18 (s, 3 H,
Meg), 0.72 (s, 3 H, Meg), 5.79 (s, 1 H, Hd), 2.14 (m, 2 H, He), 1.52
(m, 1 H, Hf), 3.38 (m, 1 H, Hb), 2.75 (m, 1 H, Hh), 1.04 (d, 1 H,
Hh), 6.62-6.85 (m, 4 H, m,o,p-H). 13C-{1H} NMR (C6D6, 297

1836 Inorganic Chemistry, Vol. 50, No. 5, 2011
Otero et al.
[R]D25 -27.12 (c 1.00, THF). Anal. Calcd for C32H44LiN5O: C,
2 H, He), 1.78 (m, 1 H, Hf), 2.31 (m, 1 H, Hb), 2.10 (m, 1 H, Hh,h),
0.74 (d, 1 H, Hh,h), 6.69 (t, 2 H, JHH = JHF = 8.6 Hz, m-H), 6.30
(dd, 2 H, JHH = 9.3 Hz, JHF = 4.3 Hz, o-H), 3.62 (m, 4 H, THF),
1.77 (m, 4 H, THF). 13C-{1H} NMR (C6D6, 297 K): δ 74.1 (CH),
74.15; H, 8.24; N, 16.02. Found: C, 74.01; H, 8.22; N, 15.84. 1H
NMR (C6D6, 297 K; major isomer): δ 6.59 (d, 1 H, CH), 5.67 (m,
0
1 H, CHa), 5.53 (s, 2 H, H4,4 ), 2.16 (s, 3 H, Me3), 2.14 (s, 3 H,
0
0
0
0
Me3 ), 2.41 (s, 3 H, Me5), 2.28 (s, 3 H, Me5 ), 1.12 (s, 3 H, Meg),
0.50 (s, 3 H, Meg), 4.15 (d, 1 H, Hd), 1.98 (m, 2 H, He), 1.80 (m, 1
H, Hf), 2.36 (m, 1 H, Hb), 2.25 (m, 1 H, Hh,h), 0.80 (m, 1 H, Hh,h),
6.86 (d, 2 H, m-H), 6.54 (d, 2 H, o-H), 2.07 (s, 3 H, Me) 3.62 (m,
4 H, THF), 1.77 (m, 4 H, THF). 13C-{1H} NMR (C6D6, 297 K):
60.1 (Ca), 107.8-106.4 (C4,4 ), 147.6-147.5 (C3,3 ), 144.6-140.2
0
0
0
(C5,5 ), 13.7-13.5 (Me3,3 ), 11.5-11.1 (Me5,5 ), 26.3 (Meg), 21.1
(Meg), 122.9 (Cd), 31.8 (Ce), 38.1 (Cg), 40.8 (Cf), 42.0 (Cb), 113.1
(Cc), 31.4 (Ch), 115.5 (d, JCF = 22.1 Hz, m-C), 114.9 (d, JCF
=
7.6 Hz, o-C), 156.3 (d, JCF = 234.2 Hz, p-C), 157.2 (ipso-C),
67.0-25.1 (THF).
0
0
δ 74.2 (CH), 59.7 (Ca), 107.8-106.3 (C4,4 ), 148.0-147.5 (C3,3 ),
0
0
0
141.2-140.0 (C5,5 ), 13.7-13.5 (Me3,3 ), 11.6-11.1 (Me5,5 ), 26.3
(Meg), 21.2 (Meg), 122.7 (Cd), 31.9 (Ce), 38.1 (Cg), 40.9 (Cf), 42.1
(Cb), 114.3 (Cc), 31.4 (Ch), 20.5 (MePh), 129.7 (m-C), 114.3
(o-C), 145.0 (p-C), 145.2 (ipso-C), 67.0-25.2 (THF).
1H NMR (C6D6, 297 K; minor is0omer): δ 6.48 (d, 1 H, CH),
5.48 (m, 1 H, CHa), 5.50 (s, 2 H, H4,4 ), 2.14 (s, 3 H, Me3), 2.11 (s,
0
0
3 H, Me3 ), 2.33 (s, 3 H, Me5), 2.21 (s, 3 H, Me5 ), 1.15 (s, 3 H,
Meg), 0.47 (s, 3 H, Meg), 4.58 (d, 1 H, Hd), 1.95 (m, 2 H, He), 1.78
(m, 1 H, Hf), 2.31 (m, 1 H, Hb), 2.10 (m, 1 H, Hh,h), 0.74 (d, 1 H,
1H NMR (C6D6, 297 K; minor is0omer): δ 6.53 (d, 1 H, CH),
5.67 (m, 1 H, CHa), 5.53 (s, 2 H, H4,4 ), 2.16 (s, 3 H, Me3), 2.14 (s,
H
JHH = 9.2 Hz, JHF = 4.3 Hz, o-H), 3.62 (m, 4 H, THF), 1.77 (m,
h,h), 6.79 (t, 2 H, JHH = JHF = 8.7 Hz, m-H), 6.22 (dd, 2 H,
0
0
3 H, Me3 ), 2.41 (s, 3 H, Me5), 2.28 (s, 3 H, Me5 ), 1.17 (s, 3 H,
Meg), 0.54 (s, 3 H, Meg), 4.54 (d, 1 H, Hd), 1.98 (m, 2 H, He), 1.80
(m, 1 H, Hf), 2.36 (m, 1 H, Hb), 2.25 (m, 1 H, Hh,h), 0.80 (m, 1 H,
4 H, THF). 13C-{1H} NMR (C6D6, 297 K): δ 074.5 (CH), 60.5
0
(Ca),0 107.5-106.8 (C4,40 ), 147.6-147.5 (C3,3 ), 143.7-141.1
0
H
h,h), 6.97 (d, 2 H, m-H), 6.48 (d, 2 H, o-H), 2.07 (s, 3 H, Me),
(C5,5 ), 14.1-14.0 (Me3,3 ), 11.2-10.9 (Me5,5 ), 26.2 (Meg), 20.9
3.62 (m, 4 H, THF), 1.77 (m, 4 H, THF). 13C-{1H0} NMR (C6D6,
(Meg), 122.7 (Cd), 32.0 (Ce), 38.0 (Cg), 41.3 (Cf), 42.5 (Cb), 113.0
297 K): δ 75.0 (CH), 59.8 (Ca), 107.6-106.7 (C4,4 ), 148.0-147.5
(Cc), 31.4 (Ch), 115.1 (d, JCF = 22.2 Hz, m-C), 114.3 (d, JCF
=
0
0
0
(C3,3 ), 140.2-140.0 (C5,5 ), 14.2-14.2 (Me3,3 ), 11.3-11.3
7.3 Hz, o-C), 156.8 (d, JCF = 234.8 Hz, p-C), 157.3 (ipso-C),
67.0-25.2 (THF).
0
(Me5,5 ), 25.7 (Meg), 20.9 (Meg), 122.4 (Cd), 32.0 (Ce), 38.1
(Cg), 41.3 (Cf), 42.6 (Cb), 113.8 (Cc), 31.4 (Ch), 20.5 (MePh),
129.8 (m-C), 113.8 (o-C), 145.0 (p-C), 145.5 (ipso-C), 67.0-25.2
(THF).
Synthesis of [Li(K3-clbpza)(THF)] (13). The synthetic proce-
dure was the same as for complex 10, using bdmpzm (1.00 g, 4.89
mmol), 1.6 M BunLi (3.06 cm3, 4.89 mmol) in hexane, and imine
7 (1.27 g, 4.89 mmol), to give compound 13 as a red solid. The
yield was 90%, and the diastereomeric excess was 86% (de).
[R]D25 -6.38 (c 1.00, CH2Cl2). Anal. Calcd for C31H41LiClN5O:
C, 69.02; H, 7.03; N, 14.91. Found: C, 69.23; H, 7.16; N, 14.84.
Synthesis of [Li(K3-mobpza)(THF)] (11). The synthetic proce-
dure was the same as for complex 10, using bdmpzm (1.00 g, 4.89
mmol), 1.6 M BunLi (3.06 cm3, 4.89 mmol) in hexane, and imine
3 (1.25 g, 4.89 mmol), to give compound 11 as a red solid. The
yield was 75%, and the diastereomeric excess was 50% (de).
[R]D25 -22.21 (c 1.00, THF). Anal. Calcd for C32H44LiN5O2: C,
71.53; H, 7.95; N, 15.45. Found: C, 71.55; H, 7.98; N, 15.40. 1H
1H NMR (C6D6, 297 K; major isomer): δ 6.49 (d, 1 H, CH), 5.50
0
(m, 1 H, CHa), 5.50 (s, 2 H, H4,4 ), 2.13 (s, 3 H, Me3), 2.10 (s, 3 H,
0
0
Me3 ), 2.28 (s, 3 H, Me5), 2.18 (s, 3 H, Me5 ), 1.08 (s, 3 H, Meg),
0.40 (s, 3 H, Meg), 4.21 (d, 1 H, Hd), 1.93 (m, 2 H, He), 1.76 (m,
1 H, Hf), 2.26 (m, 1 H, Hb), 2.18 (m, 1 H, Hh,h), 0.75 (m, 1 H, Hh,h),
6.95 (d, 2 H, m-H), 6.23 (d, 2 H, o-H), 3.62 (m, 4 H, THF), 1.77
(m, 4 H, THF). 13C-{1H} NMR (C6D6, 297 K): δ 74.0 (CH), 59.6
NMR (C6D6, 297 K; major isomer): δ 6.56 (d, 1 H, CH), 5.58 (d,
0
1 H, CHa), 5.51 (s, 2 H, H4,4 ), 2.12 (s, 3 H, Me3), 2.08 (s, 3 H,
0
0
Me3 ), 2.40 (s, 3 H, Me5), 2.25 (s, 3 H, Me5 ), 1.11 (s, 3 H, Meg),
0.47 (s, 3 H, Meg), 4.29 (d, 1 H, Hd), 1.97 (m, 2 H, He), 1.77 (m, 1
H, Hf), 2.40 (s, 1 H, Hb), 2.20 (m, 1 H, Hh,h), 0.71 (m, 1 H, Hh,h),
6.52-6.64 (m, 4H, m-H or o-H), 3.29 (s, 3 H, Me), 3.68 (m, 4 H,
0
0
(Ca),0 107.8-106.4 (C4,40 ), 147.6-145.9 (C3,3 ), 141.0-140.1
0
(C5,5 ), 13.7-13.5 (Me3,3 ), 11.5-11.0 (Me5,5 ), 26.2 (Meg), 20.8
(Meg), 123.0 (Cd), 31.8 (Ce), 38.1 (Cg), 40.8 (Cf), 42.1 (Cb), 113.6
(Cc), 31.3 (Ch), 115.2 (m-C), 115.1 (o-C), 155.2 (p-C), 157.0 (ipso-
C), 66.8-25.4 (THF).
THF), 1.84 (m, 4 H, THF). 13C-{1H} NMR (C6D6, 297 K):0 δ
0
72.9 (CH), 59.1 (Ca), 106.5-105.0 (C40 ,4 ), 146.3-146.2 0(C3,3 ),
0
143.8-138.8 (C5,5 ), 12.3-12.2 (Me3,3 ), 9.9-9.7 (Me5,5 ), 25.1
(Meg), 20.0 (Meg), 121.2 (Cd), 30.6 (Ce), 36.9 (Cg), 39.6 (Cf), 40.7
(Cb), 113.3 (Cc), 30.2 (Ch), 53.8 (MeOPh), 113.5-114.1 (m-C or
o-C), 151.4 (p-C), 157.0 (ipso-C), 67.0-25.2 (THF).
1H NMR (C6D6, 297 K; minor is0omer): δ 6.45 (d, 1 H, CH),
5.50 (m, 1 H, CHa), 5.50 (s, 2 H, H4,4 ), 2.13 (s, 3 H, Me3), 2.10 (s,
0
0
3 H, Me3 ), 2.28 (s, 3 H, Me5), 2.18 (s, 3 H, Me5 ), 1.10 (s, 3 H,
Meg), 0.48 (s, 3 H, Meg), 4.73 (d, 1 H, Hd), 1.93 (m, 2 H, He), 1.76
(m, 1 H, Hf), 2.26 (m, 1 H, Hb), 2.18 (m, 1 H, Hh,h), 0.75 (m, 1 H,
1H NMR (C6D6, 297 K; minor isomer): δ 6.54 (d, 1 H, CH),
0
5.58 (d, 10H, CHa), 5.51 (s, 2 H, H4,4 ), 2.12 (s, 3 H, Me3), 2.08 (s,
0
3 H, Me3 ), 2.40 (s, 3 H, Me5), 2.25 (s, 3 H, Me5 ), 0.82 (s, 3 H,
Meg), 0.21 (s, 3 H, Meg), 4.49 (d, 1 H, Hd), 1.97 (m, 2 H, He), 1.77
(m, 1 H, Hf), 2.40 (s, 1 H, Hb), 2.20 (m, 1 H, Hh,h), 0.71 (m, 1 H,
H
h,h), 7.05 (d, 2 H, m-H), 6.09 (d, 2 H, o-H), 3.62 (m, 4 H, THF),
1.77 (m, 4 H, THF). 13C-{1H} NMR (C6D6, 297 K): δ 74.4 (CH),
0
0
59.7 (Ca), 107.5-106.8 (C4,4 ), 148.0-147.6 (C3,3 ), 144.3-140.2
0
0
0
h,h), 6.50-6.72 (m, 4H, m-H or o-H), 3.26 (s, 3 H, Me), 3.62 (m,
(C5,5 ), 14.2-13.6 (Me3,3 ), 12.1-11.0 (Me5,5 ), 25.6 (Meg), 19.8
(Meg), 122.5 (Cd), 32.8 (Ce), 38.0 (Cg), 41.0 (Cf), 43.0 (Cb), 113.9
(Cc), 31.3 (Ch), 116.0 (m-C), 115.2 (o-C), 155.3 (p-C), 157.2 (ipso-
C), 67.0-25.2 (THF).
H
4 H, THF), 1.77 (m, 4 H, THF). 13C-{1H} NMR (C6D6, 297 K):
0
0
δ 73.6 (CH), 59.7 (Ca), 106.3-105.4 (C4,4 ), 146.1-146.0 (C3,3 ),
0
0
0
144.4-139.2 (C5,5 ), 13.0-12.4 (Me3,3 ), 10.2-10.0 (Me5,5 ), 24.7
(Meg), 19.8 (Meg), 121.3 (Cd), 31.4 (Ce), 36.8 (Cg), 39.9 (Cf), 41.6
(Cb), 113.0 (Cc), 30.2 (Ch), 53.6 (MeOPh), 114.5-113.4 (m-C or
o-C), 151.6 (p-C), 157.1 (ipso-C), 66.8-24.4 (THF).
Synthesis of [LiCl(K2-R,R-fbpzaH)(THF)] (14). In a 250 cm3
Schlenk tube, [Li(κ3-fbpza)(THF)] (12; 1.00 g, 1.90 mmol) was
dissolved in dry THF (70 cm3). Saturated aqueous ammonium
chloride (20 cm3) was added, and the mixture was concentrated
under reduced pressure. The residue was dissolved in CH2Cl2.
The addition of hexane gave a red solid. The solid was filtered off
and dried under reduced pressure to give compound 14. Yield:
Synthesis of [Li(K3-fbpza)(THF)] (12). The synthetic proce-
dure was the same as for complex 10, using bdmpzm (1.00 g,
4.89 mmol), 1.6 M BunLi (3.06 cm3, 4.89 mmol) in hexane, and
imine 4 (1.19 g, 4.89 mmol), to give compound 12 as a brown
solid. The yield was 90%, and the diastereomeric excess was
25
69%. [R]D -10.21 (c 1.00, THF). Anal. Calcd for C31H42-
LiClFN5O: C, 66.26; H, 7.48; N, 12.47. Found: C, 66.31; H,
25
78% (de). [R]D -4.34 (c 1.00, CH2Cl2). Anal. Calcd for
C31H41LiFN5O: C, 71.53; H, 7.28; N, 15.45. Found: C, 71.58;
7.52; N, 12.45. 1H NMR (C6D6, 297 K): δ 6.71 (m, 1 H, CH),
0
H, 7.32; N, 15.40. 1H NMR (C6D6, 297 K; major i0somer): δ 6.52
5.55 (m, 1 H, CHa), 5.46 (s, 1 H, H4), 5.41 (s, 1 H, H4 ), 2.13 (s, 3
0
(d, 1 H, CH), 5.50 (m, 10H, CHa), 5.50 (s, 2 H, H4,4 ), 2.14 (s, 3 H,
H, Me3), 2.08 (s, 3 H, Me3 ), 2.28 (s, 3 H, Me5), 2.23 (s, 3 H,
0
0
Me3), 2.11 (s, 3 H, Me3 ), 2.33 (s, 3 H, Me5), 2.21 (s, 3 H, Me5 ),
1.10 (s, 3 H, Meg), 0.42 (s, 3 H, Meg), 4.15 (d, 1 H, Hd), 1.95 (m,
Me5 ), 0.41 (s, 3 H, Meg), 1.11 (s, 3 H, Meg), 5.49 (s, 1 H, Hd), 1.93
(m, 2 H, He), 1.76 (m, 1H, Hf), 2.37(s, 1 H, Hb), 2.22(m, 1H, Hh,h),

Article
Inorganic Chemistry, Vol. 50, No. 5, 2011 1837
0.72 (d, 1 H, Hh,h), 6.71 (t, 2 H, JHH = JHF = 8.7 Hz, m-H), 6.30
(dd, 2 H, JHH = 9.3 Hz, JHF = 4.3 Hz, o-H), 8.95 (s, 1 H, NH),
3.57 (m, 4 H, THF), 1.39 (m, 4 H, THF). 13C-{1H0} NMR (C6D6,
297 K): δ 73.7 (CH), 60.3 (Ca), 107.9-106.5 (C4,4 ), 147.7-144.4
15.66. Found: C, 72.51; H, 7.52; N, 15.68. 1H NMR (C6D6, 297
0
K): δ 6.53 (d, 1 H, CH), 5.51 (s, 1 0H, CHa), 5.51 (s, 2 H, H4,4 ),
2.12 (s, 3 H, Me3), 2.07 (s, 3 H, Me3 ), 2.35 (s, 3 H, Me5), 2.21 (s, 3
0
H, Me5 ), 1.10 (s, 3 H, Meg), 0.41 (s, 3 H, Meg), 4.49 (s, 1 H, Hd),
1.93 (m, 2 H, He), 1.77 (m, 1 H, Hf), 2.40 (s, 1 H, Hb), 2.10 (m, 1
H, Hh,h), 0.71 (m, 1 H, Hh,h), 6.68-6.35 (m, 4H, m-H or o-H),
0
0
0
(C3,3 ), 147.2-143.4 (C5,5 ), 13.6-13.1 (Me3,3 ), 11.5-11.2
0
(Me5,5 ), 26.2 (Meg), 21.1 (Meg), 123.2 (Cd), 31.9 (Ce), 38.1
8.72 (s, 1 H, NH). 13C-{1H}0NMR (C6D6, 297 K): δ 74.0 (CH),
(Cg), 40.8 (Cf), 42.2 (Cb), 140.6 (Cc), 31.4 (Ch), 115.5 (d, JCF
22.1 Hz, m-C), 115.2 (d, JCF = 6.9 Hz, o-C), 156.4 (d, JCF
235.7 Hz, p-C), 141.7 (ipso-C), 70.4-27.1 (THF).
=
=
0
60.0 (Ca), 106.3-106.1 (C4,4 ), 148.0-147.6 (C3,3 ), 143.8-141.2
0
0
0
(C5,5 ), 13.7-13.5 (Me3,3 ), 11.6-11.1 (Me5,5 ), 26.3 (Meg), 21.2
(Meg), 123.1 (Cd), 31.9 (Ce), 38.1 (Cg), 40.8 (Cf), 42.0 (Cb), 140.2
=
Synthesis of [LiCl(K2-R,R-clbpzaH)(THF)] (15). The syn-
thetic procedure was the same as for complex 14, using [Li(κ3-
clbpza)(THF)] (13) and saturated aqueous ammonium chloride
(Cc), 31.4 (Ch), 115.5 (d, JCF = 22.1 Hz, m-C), 114.8 (d, JCF
6.9 Hz, o-C), 156.1 (d, JCF = 235.0 Hz, p-C), 147.6 (ipso-C).
(20 cm3), to give compound 15 as a red solid. Yield: 70%. [R]D
25
Synthesis of (R,R-clbpzaH) (19). The synthetic procedure was
the same as for compound 16, using [Li(κ3-clbpza)(THF)] (13;
1.00 g, 1.85 mmol) and distilled water (33.30 μL, 1.85 mmol), to
give compound 19 as an orange solid. Yield: 75%. [R]D25 -36.01
(c 1.00, THF). Anal. Calcd for C27H34ClN5: C, 69.91; H, 7.34;
N, 15.10. Found: C, 70.05; H, 7.32; N, 15.54. 1H NMR (C6D6,
-12.46 (c 1.00, THF). Anal. Calcd for C31H42LiCl2N5O: C,
64.38; H, 7.27; N, 12.11. Found: C, 64.40; H, 7.25; N, 12.16. 1H
NMR (C6D6, 297 K): δ 6.65 (d, 1 H, CH), 5.52 (s, 1 0H, CHa),
0
5.48 (s, 2 H, H4,4 ), 2.15 (s, 03 H, Me3), 2.11 (s, 3 H, Me3 ), 2.30 (s,
3 H, Me5), 2.24 (s, 3 H, Me5 ), 0.49 (s, 3 H, Meg), 1.10 (s, 3 H, Meg),
5.42 (d, 1 H, Hd), 1.91 (m, 2 H, He), 1.74 (m, 1 H, Hf), 2.25 (s, 1 H,
Hb), 2.17 (s, 1 H, Hh,h), 0.73 (m, 1 H, Hh,h), 6.97 (d, 2 H, m-H),
6.25 (d, 2 H, o-H), 8.47 (s, 1 H, NH), 3.62 (m, 4 H, THF), 1.77
(m, 4 H, THF). 13C-{1H} NMR (C6D6, 297 K): δ 73.6 (CH), 60.0
297 0K): δ 6.51 (d, 1 H, CH), 5.50 (s, 1 H, CHa), 5.51 (s, 2 H,
0
H
4,4 ), 2.13 (s, 3 H, Me3), 2.09 (s, 3 H, Me3 ), 2.31 (s, 3 H, Me5),
0
2.22 (s, 3 H, Me5 ), 1.09 (s, 3 H, Meg), 0.40 (s, 3 H, Meg), 4.49 (d,
1 H, Hd), 1.92 (m, 2 H, He), 1.75 (m, 1 H, Hf), 2.28 (s, 1 H, Hb),
2.15 (s, 1 H, Hh,h), 0.74 (m, 1 H, Hh,h), 6.95 (d, 2 H, m-H), 6.27 (d,
0
0
(Ca),0 108.5-106.5 (C4,40 ), 147.3-145.1 (C3,3 ), 147.6-142.9
0
2 H, o-H), 8.50 (s, 1 H, NH). 13C-{1H} NMR (C6D6, 297 K):0 δ
(C5,5 ), 13.5-13.1 (Me3,3 ), 11.5-11.3 (Me5,5 ), 26.2 (Meg), 21.1
(Meg), 123.1 (Cd), 32.7 (Ce), 38.0 (Cg), 40.8 (Cf), 42.0 (Cb), 140.7
(Cc), 31.8 (Ch), 115.8-115.6 (m-C), 114.6 (o-C), 156.8 (p-C),
161.3 (ipso-C), 67.0-25.2 (THF).
0
73.9 (CH), 59.7 (Ca), 107.9-106.1 (C4,4 ), 148.0-147.7 (C3,3 ),
0
0
0
144.3-141.2 (C5,5 ), 13.7-13.6 (Me3,3 ), 11.5-11.0 (Me5,5 ), 26.3
(Meg), 21.2 (Meg), 123.1 (Cd), 32.7 (Ce), 38.1 (Cg), 40.8 (Cf), 42.1
(Cb), 140.2 (Cc), 31.8 (Ch), 115.7-115.5 (m-C), 115.1 (o-C),
156.0 (p-C), 160.0 (ipso-C).
Synthesis of (R,R-mbpzaH) (16). In a 250 cm3 Schlenk tube,
[Li(κ3-mbpza)(THF)] (10; 1.00 g, 1.92 mmol) was dissolved in
dry THF (70 cm3). Distilled water (34.55 μL, 1.92 mmol) was
added, and the solution was stirred for 1 h. The solvent was re-
moved under vacuum conditions, and the resulting solid was
extracted with dichloromethane. The solvent was removed to
give 16 as a red solid. Yield: 63%. [R]D25 -20.43 (c 1.00, THF).
Anal. Calcd for C28H37N5: C, 75.85; H, 8.35; N, 15.80. Found:
Preparation of Group 4 Complexes 20-26. Synthesis of
[TiCl3(K3-R,R-fbpza)] (20). In a 250 cm3 Schlenk tube, TiCl4-
(THF)2 (0.50 g, 1.50 mmol) was dissolved in dry THF (50 cm3)
and cooled to -70 °C. A cooled (-70 °C) solution of [Li(κ3-
fbpza)(THF)] (12; 0.79 g, 1.50 mmol) in dry THF (50 cm3) was
added, and the resulting orange solution was stirred for 12 h.
The solvent was removed under vacuum conditions, and the
resulting solid was extracted with dichloromethane. The solvent
was removed to give complex 20 as a red solid. This solid was
C, 75.87; H, 8.37; N, 15.76. 1H NMR (C6D6, 297 K): δ 6.51 (m,
0
1 H, CH), 5.60 (s, 1 H, CHa), 5.50 (s, 2 H, H4,4 ), 1.98 (s, 3 H, Me3),
0
0
1.96 (s, 3 H, Me3 ), 2.13 (s, 3 H, Me5), 2.11 (s, 3 H, Me5 ), 1.10 (s,
3 H, Meg), 0.45 (s, 3 H, Meg), 5.48 (m, 1 H, Hd), 1.92 (m, 2 H, He),
1.70 (m, 1 H, Hf), 2.42 (s, 1 H, Hb), 2.10 (m, 1 H, Hh,h), 0.73 (d,
1 H, Hh,h), 6.85 (m, 2 H, m-H), 6.59 (m, 2 H, o-H), 2.07 (s, 3 H,
Me), 11.64 (s, 1 H, NH). 13C-{1H} NMR (C6D6, 297 K): δ 70.0
25
crystallized from dichloromethane/n-hexane. Yield: 65% [R]D
-18.26 (c 1.00, THF). Anal. Calcd for C27H33Cl3FN5Ti: C, 53.98;
H, 5.50; N, 11.66. Found: C, 54.01; H, 5.51; N, 11.64. 1H NMR
(DMSO, 297 K): δ 6.40 (m, 1 H, CH), 5.47 (s, 1 H, CHa), 5.60 (s, 1
0
0
0
0
(CH), 59.70(Ca), 107.7-106.1 (C4,4 ), 148.0-147.5 (C3,3 ), 145.0-
H, H4), 5.32 (s, 1 H, H4 ), 2.11 (s, 3 H, Me3), 2.01 (s, 3 H, Me3 ), 2.27
0
0
0
141.3 (C5,5 ), 13.9-13.7 (Me3,3 ), 11.6-11.1 (Me5,5 ), 26.3 (Meg),
21.3 (Meg), 122.9 (Cd), 31.8 (Ce), 38.2 (Cg), 40.9 (Cf), 42.0 (Cb),
140.0 (Cc), 31.5 (Ch), 129.7 (m-C), 114.2 (o-C), 145.0 (p-C), 145.1
(ipso-C), 3.6 (Me).
(s, 3 H, Me5), 2.24 (s, 3 H, Me5 ), 1.14 (s, 3 H, Meg), 0.42 (s, 3 H,
Meg), 4.78 (s, 1 H, Hd), 1.93 (m, 2 H, He), 1.76 (m, 1 H, Hf), 2.50 (s,
1 H, Hb), 2.23 (d, 1 H, Hh,h), 0.71 (d, 1 H, Hh,h), 6.33 (t, 2 H, JHH
=
JHF = 8.7Hz, m-H), 6.36 (dd, 2H, JHH =7.1Hz, JHF =4.3Hz, o-
H). 13C-{1H} NMR (DMSO, 297 K): δ 74.4 (CH), 60.4 (Ca0),
Synthesis of (R,R-mobpzaH) (17). The synthetic procedure
was the same as for compound 16, using [Li(κ3-mobpza)(THF)]
(11; 1.00 g, 1.86 mmol) and distilled water (33.48 μL, 1.86 mmol),
to give compound 17 as a red solid. Yield: 60%. [R]D25 -23.56 (c
1.00, THF). Anal. Calcd for C28H37N5O: C, 73.20; H, 8.06; N,
0
0
107.9-106.5 (C4,4 ), 147.6-147.3 (C3,3 ), 141.5-140.4 (C5,5 ),
0
0
13.6-12.8 (Me3,3 ), 11.6-11.2 (Me5,5 ), 26.2 (Meg), 21.3 (Meg),
123.3 (Cd), 31.5 (Ce), 38.1 (Cg), 40.8 (Cf), 42.3 (Cb), 141.2 (Cc), 31.9
(Ch), 115.4 (d, JCF = 22.1 Hz, m-C), 115.2 (d, JCF = 6.9 Hz, o-C),
157.4 (d, JCF = 235.7 Hz, p-C), 154.2 (ipso-C).
15.25. Found: C, 73.29; H, 8.12; N, 15.20. 1H NMR (C6D6, 297
0
K): δ 6.59 (d, 1 H, CH), 5.61 (m, 1 H, CHa), 5.51 (s, 2 H, H4,4 ),
Synthesis of [ZrCl3(K3-R,R-fbpza)] (21). Method a. The syn-
thetic procedure was the same as for complex 20, using ZrCl4
(0.50 g, 2.14 mmol) and [Li(κ3-fbpza)(THF)] (12; 1.13 g, 2.14
mmol), to give complex 21 as a light yellow solid. Yield: 67%.
Method b. In a 250 cm3 Schlenk tube, [Zr(NMe2)3(κ3-R,R-
fbpza)] (24; 0.50 g, 0.75 mmol) was dissolved in dry toluene
(50 cm3). Chlorotrimethylsilane (243.00 μL, 2.25 mmol) was
added, and the solution was stirred for 5 h. The color of the
resulting solution changed from dark yellow to light yellow. The
solvent was removed under vacuum conditions and washed with
n-hexane to give complex 21. Yield: 75%. [R]D25 -11.25 (c 1.00,
THF). Anal. Calcd for C27H33Cl3FN5Zr: C, 50.34; H, 5.16; N,
0
2.14 (s, 30H, Me3), 2.10 (s, 3 H, Me3 ), 2.42 (s, 3 H, Me5), 2.27 (s,
3 H, Me5 ), 1.12 (s, 3 H, Meg), 0.49 (s, 3 H, Meg), 4.24 (d, 1 H, Hd),
1.97 (m, 2 H, He), 1.78 (m, 1 H, Hf), 2.41 (m, 1 H, Hb), 2.21 (m,
1 H, Hh,h), 0.75 (d, 1 H, Hh,h), 6.54-6.67 (m, 4H, m-H or o-H),
3.28 (s, 3 H, Me), 11.70 (s, 1 H, NH). 13C-{1H} NMR (C6D6,
0
297 K): δ 74.2 (CH), 60.4 (Ca), 107.8-106.1 (C4,4 ), 148.0-1470.5
0
0
0
(C3,3 ), 145.1-141.3 (C5,5 ), 13.7-13.5 (Me3,3 ), 11.7-11.2(Me5,5 ),
26.4 (Meg), 21.3 (Meg), 122.8 (Cd), 31.9 (Ce), 38.2 (Cg), 41.0 (Cf),
42.0 (Cb), 140.2 (Cc), 31.5 (Ch), 115.4 (m-C), 114.8 (o-C), 152.8
(p-C), 158.2 (ipso-C), 55.1 (OMe).
Synthesis of (R,R-fbpzaH) (18). The synthetic procedure was
the same as for compound 16, using [Li(κ3-fbpza)(THF)] (12;
1.00 g, 1.90 mmol) and distilled water (34.29 μL, 1.90 mmol), to
give compound 18 as an orange solid. Yield: 70%. [R]D25 -26.84
(c 1.00, THF). Anal. Calcd for C27H34FN5: C, 72.48; H, 7.60; N,
1
10.87. Found: C, 50.36; H, 5.12; N, 10.84. H NMR (DMSO,
297 K): δ 6.30 (d, 1 H, CH), 5.50 (bs, 1 H, CHa), 5.75 (s, 1 H, H4),
0
0
5.73 (s, 1 H, H4 ), 2.04 (s, 3 H, Me3), 2.02 (s, 3 H, Me3 ), 2.38 (s, 3
0
H, Me5), 2.37 (s, 3 H, Me5 ), 1.16 (s, 3 H, Meg), 0.28 (s, 3 H, Meg),

1838 Inorganic Chemistry, Vol. 50, No. 5, 2011
Otero et al.
Table 4. Crystal Data and Structure Refinement for 5, 12, 14, 15, and 24
5
12
14
15
24
molecular formula
fw
temp (K)
wavelength (A)
cryst syst
space group
C16H18FN
243.31
180(2)
0.71073
monoclinic
C2
C31H41FLiN5O
525.68
180(2)
0.71073
monoclinic
P21
C31H42ClFLiN5O
562.09
180(2)
0.71073
tetragonal
P43
C31H42Cl2LiN5O
578.54
180(2)
0.71073
tetragonal
P43
C33H51FN8Zr
670.04
250(2)
0.71073
orthorhombic
P212121
a (A)
b (A)
10.707(4)
6.833(2)
18.393(6)
98.577(5)
1330.5(8)
4
1.215
0.080
520
0.65 ꢀ 0.43 ꢀ 0.02
-11 e h e 11
-7 e k e 7
-19 e l e 19
3048
10.371(2)
19.001(4)
15.118(3)
96.642(7)
2959(1)
4
1.180
0.077
1128
0.31 ꢀ 0.23 ꢀ 0.18
-10 e h e 12
-22 e k e 20
-17 e l e 14
15214
14.336(1)
14.336(1)
15.199(3)
14.5316(7)
14.5316(7)
15.179(2)
13.097(8)
10.595(6)
25.587(5)
c (A)
β (deg)
vol (A3)
3123.8(7)
4
1.195
0.159
1200
0.27 ꢀ 0.13 ꢀ 0.10
-17 e h e 17
-17 e k e 17
-18 e l e 17
23769
3205.2(4)
4
1.199
0.234
1232
0.26 ꢀ 0.16 ꢀ 0.08
-17 e h e 17
-16 e k e 17
-18 e l e 18
23385
3551(3)
4
1.253
0.348
1416
0.51 ꢀ 0.45 ꢀ 0.30
-15 e h e 11
-8 e k e 12
-30 e l e 27
11540
Z
density (calculated) (g/cm3)
abs coeff (mm-1
F(000)
)
cryst size (mm3)
index ranges
reflns collected
independent reflns
1639
8945
5474
5560
5884
[R(int) = 0.0578]
1639/1/166
1.017
R1 = 0.0532
wR2 = 0.1266
[R(int) = 0.1172]
8945/53/709
0.952
R1 = 0.0850
wR2 = 0.1588
0.12(3)
R(int) = 0.0961
5474/1/368
0.949
R1 = 0.0626
wR2 = 0.1486
-0.20(12)
0.318/-0.246
R(int) = 0.1152
5560/1/367
1.006
R1 = 0.0643
wR2 = 0.1596
0.00(11)
R(int) = 0.0759
5884/0/400
0.996
data/restraints/params
goodness-of-fit on F2
final R indices [I > 2σ(I)]a,b
R1 = 0.0629
wR2 = 0.1138
-0.08(7)
absolute structure param
largest diff. peak/hole, e.A-3
0.179 and -0.192
0.253/-0.248
0.295/-0.261
0.480/-0.645
P
P
P
P
P
a R = ||Fo| - |Fc|/ |Fo|. b wR = { w(Fo2 - Fc2)2/ w(Fo2)2}1/2. GOF = { [w((Fo2 - Fc2)2)/(n - p)}1/2, where n = number of reflections and p =
total number of parameters refined.
5.36 (t, 1 H, Hd), 1.97 (d, 2 H, He), 1.83 (bs, 1 H, Hf), 2.45 (m,
1 H, Hb), 2.12 (d, 1 H, Hh,h), 6.84 (t, 2 H, JHH = JHF = 8.8 Hz,
m-H), 6.55 (dd, 2 H, JHH = 6.8 Hz, JHF = 4.4 Hz, o-H).
13C-{1H} NMR (DMSO, 297 K): δ 73.8 (CH), 60.6 (Ca), 106.0
11.02. Found: C, 61.28; H, 8.85; N, 11.16. 1H NMR (C6D6, 297
K): δ 6.51 (d, 10 H, CH), 5.51 (bs, 1 H, CHa), 5.55 (s, 01 H, H4),
5.51 (s, 1 H, H4 ), 2.14 (s, 3 H, Me3), 2.10 (s, 3 H, Me3 ), 2.32 (s,
0
3 H, Me5), 2.22 (s, 3 H, Me5 ), 1.10 (s, 3 H, Meg), 0.41 (s, 3 H, Meg),
4.10 (d, 1 H, Hd), 1.96 (m, 2 H, He), 1.80 (m, 1 H, Hf), 2.34 (m,
0
0
0
(C4,4 ), 146.3-146.0 (C3,3 ), 140.1-139.0 (C5,5 ), 13.5-13.3
0
0
(Me3,3 ), 11.2-11.0 (Me5,5 ), 26.0 (Meg), 21.0 (Meg), 121.3
(Cd), 30.4 (Ce), 37.5 (Cg), 39.8 (Cf), 41.0 (Cb), 141.0 (Cc), 30.9
(Ch), 114.8 (d, JCF = 22.2 Hz, m-C), 114.1 (d, JCF = 7.1 Hz,
o-C), 158.1 (d, JCF = 235.6 Hz, p-C), 153.4 (ipso-C).
1H, Hb), 2.34(m, 1H, Hh,h), 0.76(d, 1H, Hh,h), 6.33 (t, 2 H, JHH
=
JHF = 8.5 Hz, m-H), 6.21 (dd, 2 H, JHH = 6.7 Hz, JHF = 4.5 Hz,
o-H), 1.20-1.51 (m, 18 H, OCH(CH3)2), 4.70-4.84 (m, 3 H,
OCH(CH3)2). 13C-{1H} NMR (C6D6, 297 K): δ 73.1 (CH), 60.1
0
0
Synthesis of [Ti(OEt)3(K3-R,R-fbpza)] (22). In a 250 cm3
Schlenk tube, Ti(OEt)4 (0.50 g, 2.19 mmol) was dissolved in
dry toluene (50 cm3). A solution of (R,R-fbpzaH) (18; 0.98 g,
2.19 mmol) in toluene was added, and the resulting solution was
stirred for 12 h at room temperature. The solvent was removed
under vacuum conditions to give complex 22 as a yellow solid.
(Ca),0 107.8-106.4 (C4,40 ), 148.0-147.5 (C3,3 ), 141.1-140.2
0
(C5,5 ), 13.7-13.5 (Me3,3 ), 11.5-11.1 (Me5,5 ), 26.3 (Meg), 21.2
(Meg), 122.9 (Cd), 31.4 (Ce), 38.1 (Cg), 40.8 (Cf), 42.1 (Cb), 141.1
(Cc), 31.8 (Ch), 115.6 (d, JCF = 22.2 Hz, m-C), 115.2 (d, JCF
=
6.9 Hz, o-C), 155.4 (d, JCF = 234.6 Hz, p-C), 157.2 (ipso-C),
28.5-28.0 (OCH(CH3)2), 27.5-27.0 (OCH(CH3)2), 26.5-26.1
(OCH(CH3)2), 75.8 (OCH(CH3)2), 75.5 (OCH(CH3)2), 74.0
(OCH(CH3)2).
25
This solid was crystallized from n-hexane. Yield: 70%. [R]D
-13.85 (c 1.00, THF). Anal. Calcd for C33H48FN5O3Ti: C,
61.24; H, 8.50; N, 11.02. Found: C, 61.28; H, 8.85; N, 11.16. 1H
Synthesis of [Zr(NMe2)3(K3-R,R-fbpza)] (24). In a 250 cm3
Schlenk tube, Zr(NMe2)4 (0.50 g, 1.87 mmol) was dissolved in
dry toluene (50 cm3). A solution of (R,R-fbpzaH) (18; 0.84 g,
1.87 mmol) in toluene was added, and the resulting solution was
stirred overnight at room temperature. The solvent was removed
under vacuum conditions and washed with n-hexane to give
complex 24 as a yellow solid. This solid was crystallized from n-
hexane. Yield: 75%. [R]D25 -18.12 (c 1.00, THF). Anal. Calcd
for C33H51FN8Zr: C, 59.15; H, 7.67; N, 16.72. Found: C, 59.12;
NMR (C6D6, 297 K): δ 6.29 (d, 1 H, CH), 5.48 (bs, 1 H, CHa),
0
5.460(s, 1 H, H4), 5.46 (s, 1 H, H4 ), 2.11 (s, 30H, Me3), 2.06 (s, 3 H,
Me3 ), 2.29 (s, 3 H, Me5), 2.13 (s, 3 H, Me5 ), 1.20 (s, 3 H, Meg),
0.40 (s, 3 H, Meg), 4.01 (d, 1 H, Hd), 1.93 (m, 2 H, He), 1.72 (m,
1 H, Hf), 2.30 (m, 1 H, Hb), 2.20 (m, 1 H, Hh,h), 0.75 (d, 1 H, Hh,h),
6.28 (t, 2 H, JHH = JHF = 8.1 Hz, m-H), 6.15 (dd, 2 H, JHH =
6.8 Hz, JHF = 4.1 Hz, o-H), 1.20-1.55 (m, 9 H, OCH2CH3),
4.20-4.80 (m, 6 H, OCH2CH3). 13C-{1H} NMR (C6D6, 297 K):
0
0
δ 73.3 (CH), 60.3 (Ca), 107.6-106.3 (C4,4 ), 148.1-148.3 (C3,3 ),
H, 7.65; N, 16.69. 1H NMR (C6D6, 297 K): δ 5.99 (d, 1 H, CH),
5,50
3,30
5,50
0
4.62 (d, 1 H, CHa), 5.46 (s, 10 H, H4), 5.45 (s, 1 H, H4 ), 2.30
(s, 30H, Me3), 2.24 (s, 3 H, Me3 ), 1.70 (s, 3 H, Me5), 1.67 (s, 3 H,
Me5 ), 1.08 (s, 3 H, Meg), 0.39 (s, 3 H, Meg), 5.40 (bs, 1 H, Hd),
1.82 (m, 2 H, He), 1.87 (m, 1 H, Hf), 2.15 (m, 1 H, Hb), 2.04 (m,
1 H, Hh,h), 0.66 (d, 1 H, Hh,h), 7.02 (m, 4H, m,o-H), 3.42 (s, 6 H,
N(CH3)2), 2.83 (s, 6 H, N(CH3)2), 2.82 (s, 6 H, N(CH3)2).
13C-{1H} NMR (C6D6, 297 K): δ 70.6 (CH), 67.8 (Ca0),
141.5-140.3 (C ), 13.5-13.5 (Me ), 11.4-11.1 (Me ), 26.3
(Meg), 21.3 (Meg), 123.0 (Cd), 31.4 (Ce), 38.2 (Cg), 40.8 (Cf), 42.2
(Cb), 141.3 (Cc), 31.9 (Ch), 115.8 (d, JCF = 22.2 Hz, m-C), 115.1
(d, JCF = 7.1 Hz, o-C), 155.4 (d, JCF = 235.1 Hz, p-C), 157.3
(ipso-C), 70.9 (OCH2CH3), 18.3 (OCH2CH3).
Synthesis of [Ti(OiPr)3(K3-R,R-fbpza)] (23). The synthetic
procedure was the same as for complex 22, using Ti(OiPr)4
(0.50 cm3, 1.71 mmol) and (R,R-fbpzaH) (18; 0.76 g, 1.71 mmol),
to give 23 as a yellow solid. Yield: 72%. [R]D25 -15.59 (c 1.00,
THF). Anal. Calcd for C36H54FN5O3Ti: C, 61.24; H, 8.50; N,
0
0
107.0-106.8 (C4,4 ), 152.3-151.3 (C3,3 ), 139.4-137.5 (C5,5 ),
0
0
12.8-12.5 (Me3,3 ), 11.0-10.6 (Me5,5 ), 26.0 (Meg), 21.2 (Meg),
121.8 (Cd), 32.0 (Ce), 38.1 (Cg), 40.7 (Cf), 42.2 (Cb), 150.3 (Cc),

Article
Inorganic Chemistry, Vol. 50, No. 5, 2011 1839
32.2 (Ch), 113.2 (d, JCF = 20.6 Hz, m-C), 118.8 (d, JCF = 6.9 Hz,
o-C), 155.0 (d, JCF = 232.7 Hz, p-C), 152.4 (ipso-C), 43.7
(N(CH3)2), 45.8 (N(CH3)2), 45.9 (N(CH3)2).
H, Hh,h), 6.93 (t, 2 H, JHH = JHF = 7.9 Hz, m-H), 7.01 (dd, 2 H,
JHH = 7.0 Hz, JHF = 4.2 Hz, o-H), 3.47 (s, 6 H, N(CH3)2).
13C-{1H} NMR0 (C6D6, 297 K): δ 70.4 (CH), 67.8 (Ca),
0
0
107.0-106.8 (C4,4 ), 151.4-150.6 (C3,3 ), 139.6-137.8 (C5,5 ), 12.9-
Synthesis of [ZrCl(NMe2)2(K3-R,R-fbpza)] (25). In a 250 cm3
Schlenk tube, [Zr(NMe2)3(κ3-R,R-fbpza)] (24; 0.50 g, 0.75
mmol) was dissolved in dry toluene (50 cm3). Chlorotrimethyl-
silane (81.00 μL, 0.75 mmol) was added, and the solution was
stirred for 1 h. The color of the resulting solution changed from
dark yellow to light yellow. The solvent was removed under
vacuum conditions and washed with n-hexane to give complex
0
0
12.6 (Me3,3 ), 11.6-11.2 (Me5,5 ), 26.4 (Meg), 21.4 (Meg), 121.3
(Cd), 32.0 (Ce), 38.3 (Cg), 40.8 (Cf), 42.6 (Cb), 151.3 (Cc), 32.2 (Ch),
111.2 (d, JCF = 20.6 Hz, m-C), 114.9 (d, JCF = 6.8 Hz, o-C), 156.5
(d, JCF = 234.7 Hz, p-C), 151.7 (ipso-C), 45.7 (N(CH3)2).
Crystal Data for 5, 12, 14, 15, and 24. A summary of crystal
data collection and refinement parameters for all compounds is
given in Table 4. The single crystals of these compounds were
mounted on a glass fiber and transferred to a Bruker X8 APEX
II CCD-based diffractometer equipped with a graphite mono-
chromated Mo KR radiation source (λ = 0.71073 A). Data were
integrated using SAINT,19 and an absorption correction was
performed with the program SADABS.20 The software package
SHELXTL version 6.1021 was used for space group determina-
tion, structure solution, and refinement by full-matrix least-squa-
res methods based on F2. All non-hydrogen atoms were refined
with anisotropic thermal parameters. Hydrogen atoms were
placed using a “riding model” and included in the refinement at
calculated positions. The absolute structure of 5 could not be
determined, as no significant anomalous scatters were present. For
12, the asymmetric unit contains two diatereoisomers, RS and RR.
On the other hand, the crystals of 12 diffracted weakly, and X-ray
data were of very low quality. The THF atoms show positional
disorder, and it was necessary to apply some restrictions.
25
25. Yield: 75%. [R]D -25.13 (c 1.00, THF). Anal. Calcd for
C31H45ClFN7Zr: C, 56.29; H, 6.86; N, 14.82. Found: C, 56.33;
H, 6.81; N, 14.81. 1H NMR (C6D6, 297 K): δ 6.02 (d, 1 H, CH),
0
4.58 (d, 1 H, CHa), 5.36 (s, 1 H, H4), 5.35 (s, 1 H, H4 ), 2.32 (s, 3
0
H, Me3), 2.27 (s, 3 H, Me3 ), 1.72 (s, 3 H, Me5), 1.69 (s, 3 H,
0
Me5 ), 0.98 (s, 3 H, Meg), 0.31 (s, 3 H, Meg), 5.40 (bs, 1 H, Hd),
1.83 (m, 2 H, He), 1.88 (m, 1 H, Hf), 2.15 (m, 1 H, Hb), 2.05 (m,
1 H, Hh,h), 0.68 (d, 1 H, Hh,h), 6.89 (t, 2 H, JHH = JHF = 8.3 Hz,
m-H), 7.02 (dd, 2 H, JHH = 6.9 Hz, JHF = 4.6 Hz, o-H), 3.50 (s,
6 H, N(CH3)2), 2.88 (s, 6 H, N(CH3)2). 13C-{1H} NMR (C6D6,
0
297 K): δ 70.3 (CH), 67.8 (Ca), 107.0-106.8 (C4,4 ), 151.3-1500.3
0
0
0
(C3,3 ), 139.5-137.7 (C5,5 ), 12.8-12.5 (Me3,3 ), 10.6-10.2(Me5,5 ),
26.3 (Meg), 21.4 (Meg), 121.8 (Cd), 32.0 (Ce), 38.3 (Cg), 40.7 (Cf),
42.3 (Cb), 150.3 (Cc), 32.2 (Ch), 112.2 (d, JCF = 21.6 Hz, m-C),
115.8 (d, JCF = 6.9 Hz, o-C), 156.0 (d, JCF = 234.7 Hz, p-C), 151.4
(ipso-C), 43.7 (N(CH3)2), 45.8 (N(CH3)2).
Synthesis of [ZrCl2(NMe2)(K3-R,R-fbpza)] (26). The synthetic
procedure was the same as for complex 25, but in this case the
reaction mixture was stirred for 5 h, using [Zr(NMe2)3(κ3-R,R-
fbpza)] (24; 0.50 g, 0.75 mmol) and chlorotrimethylsilane
(162.00 μL, 1.49 mmol), to give 26 as a light yellow solid. Yield:
65%. [R]D25 -13.10 (c 1.00, THF). Anal. Calcd for C29H39Cl2-
FN6Zr: C, 53.36; H, 6.02; N, 12.87. Found: C, 53.39; H, 6.07; N,
Acknowledgment. We gratefully acknowledge financial sup-
ꢀ
port from the Ministerio de Ciencia e Innovacion (MICINN),
Spain (Grant Nos. CTQ2008-00318/BQU, CTQ2008-05892/
BQU and Consolider-Ingenio 2010 ORFEO CSD2007-00006)
and the Junta de Comunidades de Castilla-La Mancha (Grant
No. PCI08-0010).
12.90. 1H NMR (C6D6, 297 K): δ 6.3 (d, 1 H, CH), 4.57 (d, 1 H,
0
CHa), 5.38 (0s, 1 H, H4), 5.35 (s, 1 H, H4 ), 2.42 (s, 3 H, Me3), 2.37
0
(s, 3 H, Me3 ), 1.64 (s, 3 H, Me5), 1.59 (s, 3 H, Me5 ), 1.03 (s, 3 H,
Meg), 0.35 (s, 3 H, Meg), 5.30 (bs, 1 H, Hd), 1.83 (m, 2 H, He),
1.87 (m, 1 H, Hf), 2.15 (m, 1 H, Hb), 2.06 (m, 1 H, Hh,h), 0.69 (d, 1
Supporting Information Available: Details of data collection,
refinement, atom coordinates, anisotropic displacement para-
meters, and bond lengths and angles for complexes 5, 12, 14, 15,
and 24. This material is available free of charge via the Internet
at http://pubs.acs.org.
(19) SAINTþ, v7.12a; Bruker-Nonius AXS: Madison, WI, 2004.
€
(20) Sheldrick, G. M. SADABS, version 2004/1; University of Gottingen:
€
Gottingen, Germany, 2004.
(21) SHELXTL-NT, version 6.12; Bruker-Nonius AXS: Madison, WI, 2001.