Pyridineenolato and pyridineenamido complexes of zirconium, titanium and aluminum

Article abstract of DOI:10.1016/j.poly.2004.03.009

Deprotonation of 2-acetylpyridine with KH in THF afford a potassium enolate compound (2) which reacts with Zr(NEt₂)₂Cl ₂(THF)₂ and Ti(NMe₂)₂Cl₂ to yield [CH₂=C(C₅H₄N)O-κ²N,O] ₂M(NR₂)₂ (M=Zr, R=Et, 3; M=Ti, R=Me, 4) in 84% and 76% yield, respectively. Deprotonation of imines derived from 2-acetylpyridine, (2,6-Me₂C₆H₃)N=C(C ₅H₄N)(CH₃) (5) and (2,6-iPr₂C ₆H₃)N=C(C₅H₄N)(CH₃) (6), affords potassium enamides, K[(2,6-Me₂C₆H ₃)N-C(C₅H₄N)(=CH₂)] (7) and K[(2,6-iPr₂C₆H₃)N-(C₅H ₄N)(=CH₂)] (8). Reactions of the potassium salt 7 with Zr(NEt₂)₂Cl₂(THF)₂ and Ti(NMe ₂)₂Cl₂ afford pyridineenamido complexes, [(2,6-Me₂C₆H₃)NC(C₅H ₄N)(=CH₂)-κ²N,N]₂M(NR ₂)₂ (M=Zr, R=Et, 9; M=Ti, R=Me, 10). Reaction of 8 with Zr(NEt₂)₂Cl₂(THF)₂ affords [(2,6-iPr₂C₆H₃)NC(C₅H ₄N)(=CH₂)]₂Zr(NEt₂)₂ (11) but the reaction of 8 with Ti(NMe₂)₂Cl₂ yields [(2,6-iPrC₆H₃)NC(C₅H₄N)(=CH ₂)]TiCl(NMe₂)₂ (12). Addition of excess AlMe₃ to 3 or 4 results in transmetallation of Zr or Ti to Al to afford an aluminum enolate complex, [CH₂=C(C₅H ₄N)(OAlMe₃)-κ²N,O]AlMe₂ (13). Addition of AlMe₃ to 12 results in the formation of a transmetallated complex, [(2,6-iPr₂C₆H₃)NC(C₅H ₄N)(=CH₂)]AlMe₂ (14). The solid structures of 4, 11, 13 and 14 were determined by X-ray crystallography.

Full text of DOI:10.1016/j.poly.2004.03.009

Polyhedron 23 (2004) 1587–1594
www.elsevier.com/locate/poly
Pyridineenolato and pyridineenamido complexes
of zirconium, titanium and aluminum
a
a
a
a,
b
Ui Gab Joung , Tae Ho Kim , Dae June Joe , Bun Yeoul Lee *, Dong Mok Shin ,
b
Young Keun Chung
a
Department of Molecular Science and Technology, Ajou University, San 5, Wonchondong, Suwon 442-749, Republic of Korea
b
School of Chemistry and Center for Molecular Catalysis, Seoul National University, Seoul 151-747, Republic of Korea
Received 11 February 2004; accepted 8 March 2004
Available online 15 April 2004
Abstract
Deprotonation of 2-acetylpyridine with KH in THF afford a potassium enolate compound (2) which reacts with
Zr(NEt2)2Cl2(THF)2 and Ti(NMe2)2Cl2 to yield [CH2@C(C5H4N)O-j2N,O]2M(NR2)2 (M ¼ Zr, R ¼ Et, 3; M ¼ Ti, R ¼ Me, 4) in
84% and 76% yield, respectively. Deprotonation of imines derived from 2-acetylpyridine, (2,6-Me2C6H3)N@C(C5H4N)(CH3) (5) and
(2,6-iPr2C6H3)N@C(C5H4N)(CH3) (6), affords potassium enamides, K[(2,6-Me2C6H3)N–C(C5H4N)(@CH2)] (7) and K[(2,6-
iPr2C6H3)N-(C5H4N)(@CH2)] (8). Reactions of the potassium salt 7 with Zr(NEt2)2Cl2(THF)2 and Ti(NMe2)2Cl2 afford pyri-
dineenamido complexes, [(2,6-Me2C6H3)NC(C5H4N)(@CH2)-j2N,N]2M(NR2)2 (M ¼ Zr, R ¼ Et, 9; M ¼ Ti, R ¼ Me, 10). Reaction
of 8 with Zr(NEt2)2Cl2(THF)2 affords [(2,6-iPr2C6H3)NC(C5H4N)(@CH2)]2Zr(NEt2)2 (11) but the reaction of 8 with Ti(NMe2)2Cl2
yields [(2,6-iPrC6H3)NC(C5H4N)(@CH2)]TiCl(NMe2)2 (12). Addition of excess AlMe3 to 3 or 4 results in transmetallation of Zr or
Ti to Al to afford an aluminum enolate complex, [CH2@C(C5H4N)(OAlMe3)-j2N,O]AlMe2 (13). Addition of AlMe3 to 12 results in
the formation of a transmetallated complex, [(2,6-iPr2C6H3)NC(C5H4N)(@CH2)]AlMe2 (14). The solid structures of 4, 11, 13 and 14
were determined by X-ray crystallography.
Ó 2004 Elsevier Ltd. All rights reserved.
Keywords: Enolato; Enamido; Zirconium; Titanium; Aluminum
1. Introduction
an electron-rich atom to which a Lewis acidic cocat-
alyst can bind to afford zwitterionic active complexes
(Eq. (1)). A novel activation reaction was successfully
applied to nickel complexes and recently it was ex-
panded to the early transition metal complexes with
an enamido ligand [10]. Herein, we report preparation
of pyridineenolato and pyridineenamido complexes of
titanium, zirconium and aluminum. The complexes
have an electron-rich methylene carbon to which a
Lewis acidic cocatalyst can bind.
A great deal of effort has been devoted in devel-
oping single site polymerization catalysts in both ac-
ademic and industrial fields [1]. Metal complexes
beyond metallocenes using various ligand systems in-
cluding chelating diamido [2] and phenoxy-imine [3–5]
have been developed and expansion from group 4
metal complexes to complexes based on the late
transition metals [6] has been achieved. Bazan and Lee
have described some metal complexes based on carb-
oxylato [7], carboxamido [8] and enamido ligands [9].
The complexes are characteristic since the ligands have
Y Ni
Ln
R'
R
A
Y Ni
Ln
R'
R
X
X
ð1Þ
* Corresponding author. Tel.: +82-31-219-1844; fax: +82-31-219-
1592.
E-mail address: bunyeoul@ajou.ac.kr (B.Y. Lee).
A
A = Lewis acid; X = O, CH2; Y = O, R"N
0277-5387/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2004.03.009

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U.G. Joung et al. / Polyhedron 23 (2004) 1587–1594
2. Results and discussion
2.1. Synthesis and characterization
The enamido ligand is ambiphilic. Either nitrogen or
methylene carbon can coordinate to the metal center [9].
Observation of two singlet signals at 4.8–3.7 ppm in the
1H NMR spectra (C6D6) and observation of a signal at
79–89 ppm in the 13C NMR spectra support that the
nitrogen coordinates as depicted in Eq. (3). If two pyri-
dineenamido ligands and two dialkylamido ligands co-
ordinate to the metal center to form an octahedral
complex, eight stereochemical structures are possible as
the case in the phenoxy-imine complexes [4]. In case of
the phenoxy-imine complexes, the most stable isomer
was calculated to have the structure shown below and
actually only the most stable complex was obtained.
X-ray crystallographic studies of a single crystal of 11
obtained by recrystallization in toluene reveal that the
complex has similar stereochemical structure as observed
for the phenoxy-imine complexes, with a cis-relationship
between the two dialkylamide ligands and a trans-rela-
tionship between the two amido nitrogen atoms. Since
similar signal patterns are observed for 9 and 10 in the 1H
and 13C NMR spectra, we presume they have a similar
stereochemical structure as observed for 11.
Deprotonation of 2-acetylpyridine is successfully
conducted by KH in THF (Eq. (2)). Addition of
Zr(NEt2)2Cl2(THF)2 and Ti(NMe2)2Cl2 to the potas-
sium enolate salt 2 results in clean formation of the
desired enolato complexes, [CH2@C(C5H4N)O-j2N,O]2
M(NR2)2 (M ¼ Zr, R ¼ Et, 3; M ¼ Ti, R ¼ Me, 4) in 84%
and 76% yield, respectively (Eq. (2)). The characteristic
methylene proton signals are observed at 4.99 and 4.82
ppm for 3 and at 4.99 and 4.78 ppm for 4 as singlets in
the 1H NMR spectra (C6D6). The @CH2 carbon signals
are observed at 87.63 and 85.48 ppm for 3 and 4, re-
spectively, in the 13C NMR spectra (C6D6). Single
crystals of 4 suitable for X-ray crystallography were
obtained by recrystallization in toluene and the solid
structure was confirmed.
M(NR2)2Cl2
N
O
N
N
O
KH
M(NR2)2
OK
2
Ar
1
2
3: M = Zr, R = Et
4: M = Ti, R = Me
N
O
M
N
NR2
N
Cl
M
NR2
ð2Þ
N
N
Cl
Syntheses of the imine compounds 5 [11] and 6 [12] have
been reported. The deprotonation is carried out cleanly
by KH in THF (Eq. (3)). The potassium salts are readily
soluble in a cosolvent of benzene and THF (v/v, ꢀ5:1)
N
O
Ar
In the case of the reaction of potassium salt 8 with
Ti(NMe2)2Cl2, the desired complex is not obtained.
The major product isolated by recrystallization in tol-
uene can be assigned to the structure 12 by the analysis
1
and are characterized by the H and 13C NMR spectra.
Reaction of the potassium salts with Zr(NEt2)2
Cl2(THF)2 and Ti(NMe2)2Cl2 yields the desired pyri-
dineenamido complexes 9–11 (Eq. (3)). The complexes
were isolated by recrystallization in toluene.
1
of the H NMR spectrum. The relative intensity of the
dimethylamido methyl signal is twice that observed for
10 and only one broad septet isopropyl CH signal and
two doublet isopropyl CH3 signals are observed. In the
1H NMR spectrum of 11, two septet isopropyl CH
signals and four doublet isopropyl CH3 signals are
observed.
M(NR2)2Cl2
N
KH
N
N
NK
Ar
Ar
N
5: Ar = 1,3-Me2C6H3
6: Ar = 1,3-iPr2C6H3
7: Ar = 1,3-Me2C6H3
8: Ar = 1,3-iPr2C6H3
TiCl(NMe2)2
N
ð3Þ
N
M(NR2)2
12
N
2
Ar
Transformation of the bis(dialkylamido) complex to
the dichloro or dialkyl complex is desired because the
latter is effectively activated with a common cocatalyst
such as MAO or B(C6F5)3. When chlorinating reagent,
9: Ar = 1,3-Me2C6H3, M = Zr, R = Et
10: Ar = 1,3-Me2C6H3, M = Ti, R = Me
11: Ar = 1,3-iPr2C6H3, M = Zr, R = Et

U.G. Joung et al. / Polyhedron 23 (2004) 1587–1594
1589
Me3SiCl or Me2SiCl2, is reacted with 3–4 and 9–11, a
complex mixture of products is observed in the 1H
NMR spectra. When alkylating reagent, AlMe3 (10
equivalents) is reacted with the enolate complex 3,
aiming to obtain the dimethyl zirconium complex, the
1H NMR spectrum indicates that a complex is formed
cleanly. The complete set of signals for the pyridineen-
olate ligand is observed in the 1H NMR spectra but two
methyl signals are observed at )0.04 and )0.27 ppm
with integration values of 9 and 6. The 1H and 13C
NMR spectra of the reaction product between 4 and
AlMe3 are exactly the same as those observed for the
reaction product of 3. Single crystals suitable for X-ray
crystallography were obtained by recrystallization in
pentane at )30 °C and the molecular structure was de-
termined. The product is an AlMe3-coordinated enola-
todimethylaluminum complex (Eq. (4)).
Fig. 1. Thermal ellipsoid plot (30% probability level) of the structure of
ꢀ
4. Selected bond distances (A) and angles (°): Ti(1)–O(1), 1.949(2);
Ti(1)–O(2), 1.923(2); Ti(1)–N(1), 2.282(2); Ti(1)–N(2), 2.269(2); Ti(1)–
N(3), 1.929(2); Ti(1)–N(4), 1.914(3); O(1)–C(6), 1.327(4); O(2)–C(13),
1.336(4); C(6)–C(7), 1.335(4); C(13)–C(14), 1.324(4); O(2)–Ti(1)–O(1),
154.51(9); N(4)–Ti(1)–N(1), 159.75(10); N(3)–Ti(1)–N(2), 164.92(10);
C(6)–O(1)–Ti(1), 126.10(18); C(13)–O(2)–Ti(1), 126.12(19).
N
Me
AlMe3
Al
3 or 4
Me
ð4Þ
O
Al
O(2) are measured to be 1.9°, )179.4° and )179.7°, re-
spectively. The C(6)–C(7) distance (1.335(4) A) and the
Me
Me
Me
ꢀ
ꢀ
C(13)–C(14) distance (1.324(4) A) are indicative of a
double bond between these two atoms. The O(1)–C(6)
ꢀ
distance (1.327(4) A) and the O(2)–C(13) distance
13
Several sets of signals are observed in the 1H NMR
spectrum when sterically hindered complex 11 is reacted
with AlMe3. The main product is deposited from pen-
tane solution at )30 °C as single crystals, which are
suitable for X-ray crystallography. The X-ray crystal-
lographic studies of the product reveal that the main
product is a transmetallated aluminum complex as
shown in Eq. (5).
ꢀ
(1.336(4) A) are indicative of a shortened single bond by
resonance. The dimethylamido nitrogen atoms are al-
most trigonal planar (sum of bonding angles, 359.8° and
357.1°) indicating p-electron donation to the titanium
metal.
The solid structure of 11 and selected bond distances
and angles are shown in Fig. 2. It also shows a distorted
octahedral structure. The two amido nitrogen atoms are
in a trans-relationship and the two dimethylamido li-
gands are situated in a cis-relationship. The Zr–N dis-
tances are in the order of Zr–NEt2 (2.078(3) and
N
Me
Al
AlMe3
Me
11
O
ð5Þ
ꢀ
ꢀ
2.058(3) A) <Zr–N(amido) (2.278(3) and 2.279(2) A)
ꢀ
<Zr–N(pyridine) (2.420(3) and 2.429(3) A). A ring,
(Zr(1)–N(3)–C(20)–C(25)–N(4)), formed by chelation is
coplanar (dihedral angles of N(3)–C(20)–C(25)–N(4)
and C(20)–C(25)–N(4)–Zr(1) are 1.6° and )0.3°, re-
spectively) while the other ring (Zr(1)–N(1)–C(1)–C(6)–
N(2)) is slightly out of coplanarity (dihedral angles of
N(1)–C(1)–C(6)–N(2) and C(1)–C(6)–N(2)–Zr(1) are
11.3° and )19.1°, respectively). The aryl rings are almost
perpendicular to the plane formed by chelation (dihedral
angles of C(6)–N(2)–C(8)–C(9) and C(25)–N(4)–C(27)–
C(28) are )76.4° and 78.5°, respectively). The C(6)–C(7)
14
2.2. X-ray crystallographic studies
The solid structure of 4 and selected bond distances
and angles are shown in Fig. 1. It shows a distorted
octahedral structure with a trans-relationship between
the two oxygen atoms and a cis-relationship between the
two dimethylamido ligands. All atoms in the pyridin-
eenolate ligand and the titanium atom are situated in a
plane and hence the dihedral angle of C(8)–C(13)–O(2)–
Ti(1), C(11)–C(12)–N(2)–Ti(1) and C(9)–C(8)–C(13)–
ꢀ
distance (1.366(5) A) and the C(25)–C(26) distance
ꢀ
(1.347(4) A) are indicative of a double bond although
they are slightly longer than the corresponding distances
observed for the enolate complex 4. All the diethylamido
nitrogens and amido nitrogens show trigonal planar

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U.G. Joung et al. / Polyhedron 23 (2004) 1587–1594
Fig. 4. Thermal ellipsoid plot (30% probability level) of the structure of
14.
Fig. 2. Thermal ellipsoid plot (30% probability level) of the structure of
ꢀ
11. Selected bond distances (A) and angles (°): Zr(1)–N(1), 2.420(3);
shows almost a trigonal planar structure (sum of
bonding angle, 358.0°). The Al(1)–O(1) distance
(1.847(6) A) is shorter than the Al(2)–O(1) distance
Zr(1)–N(2), 2.278(3); Zr(1)–N(3), 2.429(3); Zr(1)–N(4), 2.279(2);
Zr(1)–N(5), 2.078(3); Zr(1)–N(6), 2.058(3); N(2)–C(6), 1.390(4); N(4)–
C(25), 1.391(4); C(6)–C(7), 1.366(5); C(25)–C(26), 1.347(4); N(2)–
Zr(1)–N(4), 155.95(9); N(6)–Zr(1)–N(1), 147.50(12); N(5)–Zr(1)–N(3),
158.64(10); C(25)–N(4)–Zr(1), 123.20(19); C(6)–N(2)–Zr(1), 120.5(2).
ꢀ
ꢀ
(1.934(6) A) and the Al(1)–C distances (1.941(9) and
ꢀ
1.929(9) A) are shorter as well than the Al(2)–C dis-
ꢀ
tances (1.951(10), 1.962(11) and 1.972(11) A).
structure and hence the sum of bonding angles around
N(2), N(4), N(5) and N(6) are calculated to be 359.9°,
359.6°, 359.7° and 359.9°, respectively.
The solid structure of 13 and selected bond distances
and angles are shown in Fig. 3. Two aluminum atoms
show a distorted tetrahedral structure. All the atoms on
the pyridineenamide ligand and the two aluminum at-
oms are almost situated in a plane (dihedral angles of
C(4)–C(5)–N(1)–Al(1) and C(5)–N(1)–Al(1)–Al(2) are
)178.2° and 177.7°, respectively). The oxygen atom
The solid structure of 14 is shown in Fig. 4. The final
R indices for the refinement are too high (R1 ¼ 0:1573,
wR2 ¼ 0:3676) to do quantitative analysis for the bond
distances and angles, but it can be seen that Al(1), C(6),
N(2) and all the atoms in the pyridine ring are coplanar
and the 2,6-diisopropyl benzene ring is perpendicular to
the plane.
3. Experimental
3.1. General considerations
All manipulations were performed under an inert
atmosphere using standard glove box and Schlenk
techniques. Toluene, pentane, THF and C6D6 were
distilled from benzophenone ketyl. Zr(NEt2)2Cl2(THF)2
[13] and Ti(NMe2)2Cl2 [14] were prepared according to
the literature method. 1H NMR (400 MHz) and 13C
NMR (100 MHz) spectra were recorded on a Varian
Mercury plus 400. Elemental analyses were carried out
on a Perkin–Elmer 2400 CHN microanalyzer.
3.2. Synthesis of CH2@C(C5H4N)OK (2)
Fig. 3. Thermal ellipsoid plot (30% probability level) of the structure of
ꢀ
2-Acetylpyridine (1.00 g, 8.25 mmol) and KH (0.331 g,
8.25 mmol) were weighed in a flask and cold THF (10 ml,
)30 °C) was added. The solution was stirred for 4 h at
room temperature. The precipitated solid was filtered
and washed with THF to give a white solid (1.13 g, 86%).
The solid was not soluble in pyridine, benzene or THF.
13. Selected bond distances (A) and angles (°): Al(1)–O(1), 1.847(6);
Al(1)–N(1), 1.980(8); Al(1)–C(8), 1.941(9); Al(1)–C(9), 1.929(9);
Al(2)–O(1), 1.934(6); Al(2)–C(10), 1.951(10); Al(2)–C(11), 1.962(11);
Al(2)–C(12), 1.972(11); O(1)–C(6), 1.390(10); C(6)–C(7), 1.306(11);
C(6)–O(1)–Al(1), 117.0(6); C(6)–O(1)–Al(2), 124.1(6); Al(1)–O(1)–
Al(2), 116.9(3).

U.G. Joung et al. / Polyhedron 23 (2004) 1587–1594
1591
3.3. Synthesis of [CH2@C(C5H4N)O-j2N,O]2Zr (NEt2)2
(3)
169.57, 158.59, 154.57, 148.16, 135.32, 131.75, 128.65,
121.93, 120.77, 118.79, 69.40 (@CH2), 19.21 (CH3) ppm.
ZrCl2(NEt2)2(THF)2 (1.41 g, 3.14 mmol) was dis-
solved in THF (20 ml) and solid 2 (1.00 g, 6.28 mmol) was
added in one portion at room temperature. The solution
was stirred overnight. Solvent was removed by vacuum.
The product was extracted with toluene (15 ml ꢁ 2) and
the toluene was removed by vacuum to give a yellow solid
(1.25 g, 84%) which was analytically pure. 1H NMR
(C6D6): d 8.51 (dt, J ¼ 5:6, 1.2 Hz, 1H, py-H6), 7.01 (d,
J ¼ 8:0 Hz, 1H, py-H3), 6.60 (ddd, J ¼ 8:0, 7.2, 1.2 Hz,
1H, py-H4), 6.29 (ddd, J ¼ 7:2, 5.6, 1.2 Hz, 1H, py-H5),
4.99 (s, 1H, @CH2), 4.82 (s, 1H, @CH2), 3.73 (q, J ¼ 6:8
Hz, 4H, CH2CH3), 1.21 (t, J ¼ 6:8 Hz, 6H, CH2CH3)
ppm. 13C{1H}NMR (C6D6) d 162.31, 157.90, 146.68,
137.33, 122.37, 119.86, 87.63 (@CH2), 44.54 (CH2CH3),
16.11 (CH2CH3) ppm. Anal. Calc. (C22H32N4O2Zr): C,
55.54; H, 6.78; N, 11.78. Found: C, 55.72; H, 6.53; N,
11.38%.
3.6. Synthesis of K[(2,6-iPr2C6H3)N(C5H4N)(@CH2)]
(8)
This salt was synthesized using the same procedure
and conditions for 7, but with 6 (1.61 g, 5.74 mmol) and
KH (0.461 g, 11.5 mmol). The mixture was stirred for
two days. The yield was 1.61 g (88%). 1H NMR
(C6D6:THF-d8, 5:1): d 7.99 (d, J ¼ 8:0 Hz, 1H, py-H6),
7.70 (d, J ¼ 5:2 Hz, 1H, py-H3), 7.33 (d, J ¼ 7:2 Hz, 2H,
ph-H3 and 5), 7.20 (t, J ¼ 7:2 Hz, 1H, ph-H4), 7.12 (td,
J ¼ 8:0, 1.6 Hz, 1H, py-H5), 6.64 (td, J ¼ 8:0, 1.2 Hz,
1H, py-H4), 4.15 (s, 1H, @CH2), 3.52 (septet, J ¼ 7:2 Hz,
2H, CH(CH3)2), 3.26 (s, 1H, @CH2), 1.51 (d, J ¼ 7:2 Hz,
6H, CH(CH3)2), 1.16 (d, J ¼ 7:2 Hz, 6H, CH(CH3)2)
ppm. 13C{1H}NMR (C6D6:THF-d8, 5:1) d 164.24,
157.92, 155.83, 147.85, 142.87, 135.49, 123.54, 122.45,
120.84, 119.90, 71.60 (@CH2), 27.81 (CH(CH3)2), 26.75
(CH(CH3)2), 26.02 (CH(CH3)2) ppm.
3.4. Synthesis
Ti(NMe2)2 (4)
of
[CH2@C(C5H4N)O-j2N,O]2
3.7. Synthesis of [(2,6-Me2C6H3)NC(C5H4N)(@CH2)-
j2N,N]2Zr(NEt2)2 (9)
The complex was synthesized using the same proce-
dure and conditions as for 3, but with TiCl2(NMe2)2
(0.500 g, 2.42 mmol) and the potassium salt 2 (0.770 g,
4.84 mmol). The analytically pure red solid was isolated
by extraction with toluene (0.690 g, 76%). Single crystals
suitable for X-ray crystallography were obtained by re-
crystallization in toluene at )30 °C. 1H NMR (C6D6): d
8.57 (dt, J ¼ 5:6, 1.2 Hz, 1H, py-H6), 7.01 (dd, J ¼ 6:8,
1.2 Hz, 1H, py-H3), 6.64 (ddd, J ¼ 8:8, 6.8, 1.2 Hz, 1H,
py-H4), 6.34 (ddd, J ¼ 7:2, 5.6, 1.2 Hz, 1H, py-H5), 4.99
(s, 1H, @CH2), 4.78 (s, 1H, @CH2), 3.57 (s, 6 H, CH3)
ppm. 13C{1H}NMR (C6D6) d 163.88, 157.12, 146.39,
136.99, 122.34, 119.47, 85.48 (@CH2), 48.20 (CH3) ppm.
Anal. Calc. (C18H24N4O2Ti): C, 57.46; H, 6.43; N, 14.89.
Found: C, 57.03; H, 6.73; N, 14.59%.
ZrCl2(NEt2)2(THF)2 (0.523 g, 1.16 mmol) and po-
tassium salt 7 (0.609 g, 2.32 mmol) were weighed in a
flask and THF (30 ml) was added. The resulting solution
was stirred for two days. Solvent was removed under
vacuum to give a black residue which was dissolved in
toluene (40 ml). The solution was filtered and solvent
was reduced to ꢀ10 ml, at which point yellow solids
precipitated. The deposited solid was collected by fil-
1
tration (0.486 g, 61%). H NMR (C6D6): d 8.80 (br d,
J ¼ 4:8 Hz, 1H, py-H6), 7.41 (d, J ¼ 8:4 Hz, 1H, py-
H3), 7.20 (d, J ¼ 7:2 Hz, 1H, ph-H3 or 5), 7.14 (d,
J ¼ 7:2 Hz, 1H, ph-H3 or 5), 7.03 (t, J ¼ 7:2 Hz, 1H, ph-
H4), 6.71 (br t, J ¼ 7:2 Hz, 1H, py-H5), 6.23 (br t,
J ¼ 6:0 Hz, 1H, py-H4), 4.60 (s, 1H, @CH2), 3.89 (s, 1H,
@CH2), 3.22 (dq, J ¼ 14; 7.2 Hz, 2H, NCH2CH3), 2.75
(dq, J ¼ 14; 7.2 Hz, 2H, NCH2CH3), 2.64 (s, 3H, CH3),
2.51 (s, 3H, CH3), 0.71 (t, J ¼ 7:2 Hz, 6H, CH2CH3).
13C{1H}NMR (C6D6) d 158.77, 153.27, 151.58, 147.79,
137.10, 136.59, 134.97, 129.32, 128.80, 124.06, 121.19,
120.98, 83.30 (@CH2), 42.07 (CH2CH3), 22.36 (CH3),
20.46 (CH3), 13.36 (CH2CH3) ppm. Anal. Calc.
(C38H50N6Zr): C, 66.92; H, 7.39; N, 12.32. Found: C,
67.23; H, 7.45; N, 12.11%.
3.5. Synthesis of K[(2,6-Me2C6H3)N–C(C5H4N)
(@CH2)] (7)
A solution of 5 (1.20 g, 5.35 mmol) in THF (20 ml)
was added to a slurry of KH (0.429 g, 1.07 mmol) in THF
(5.0 ml) and the resulting mixture was stirred for one day
at room temperature. The dark brown solution was fil-
tered and solvent was removed under vacuum. The res-
idue was triturated in pentane to give a greenish yellow
solid. The yield was 1.15 g (82%). 1H NMR (C6D6:THF-
d8, 5:1): d 7.95 (d, J ¼ 8:0 Hz, 1H, py-H6), 7.44 (d,
J ¼ 5:2 Hz, 1H, py-H3), 7.24 (d, J ¼ 7:2 Hz, 2H, ph-
H3 and 5), 7.13 (td, J ¼ 8:0, 1.6 Hz, 1H, py-H5), 6.95 (t,
J ¼ 7:2 Hz, 1H, ph-H4), 6.62 (dd, J ¼ 7:2, 5.2 Hz, 1H,
py-H4), 4.11 (s, 1H, @CH2), 3.29 (s, 1H, @CH2), 2.30 (s,
6H, CH3) ppm. 13C{1H}NMR (C6D6:THF-d8, 5:1) d
3.8. Synthesis of [(2,6-Me2C6H3)NC(C5H4N)(@CH2)-
j2N,N]2Ti(NMe2)2 (10)
The complex was synthesized using the same proce-
dure and conditions for 9, but with TiCl2(NMe2)2
(0.174 g, 0.840 mmol) and the potassium salt 7 (0.440 g,

1592
U.G. Joung et al. / Polyhedron 23 (2004) 1587–1594
1.68 mmol). The solution was stirred for two days at 50
°C. The complex was purified by recrystallization in
toluene at )30 °C. The yield was 0.140 g (29%). 1H
NMR (C6D6): d 8.70 (d, J ¼ 4:8 Hz, 1H, py-H6), 7.48
(d, J ¼ 8:4 Hz, 1H, py-H3), 7.23 (d, J ¼ 7:6 Hz, 1H, ph-
H3 or 5), 7.15 (d, J ¼ 7:6 Hz, 1H, ph-H3 or 5), 7.04 (t,
J ¼ 7:2 Hz, 1H, ph-H4), 6.74 (td, J ¼ 7:6, 2.0 Hz, 1H,
py-H5), 6.21 (td, J ¼ 6:4, 0.8 Hz, 1H, py-H4), 4.50 (s,
1H, @CH2), 3.89 (s, 1H, @CH2), 2.63 (s, 6H, CH3), 2.45
(s, 3H, CH3). 13C{1H}NMR (C6D6) d 158.09, 153.88,
153.69, 147.67, 136.45, 135.68, 134.51, 129.56, 129.02,
123.73, 121.13, 120.83, 78.95 (@CH2), 48.13 (NCH3),
23.21 (CH3), 20.13 (CH3) ppm. Anal. Calc.
(C34H42N6Ti): C, 70.09; H, 7.27; N, 14.42. Found: C,
69.71; H, 7.52; N, 14.11%.
6.87 (td, J ¼ 7:2, 0.8 Hz, 1H, py-H5), 6.49 (t, J ¼ 6:0
Hz, 1H, py-H4), 4.56 (s, 1H, @CH2), 3.75 (s, 1H,
@CH2), 3.29 (br septet, J ¼ 6:8 Hz, 2H, CH(CH3)2),
3.01 (s, 12H, NCH3), 1.26 (d, J ¼ 7:2 Hz, 6H,
CH(CH3)2), 1.25 (d, J ¼ 7:2 Hz, 6H, CH(CH3)2) ppm.
13C{1H}NMR (C6D6) d 156.52, 155.44, 149.01, 147.40,
142.84, 137.12, 125.56, 123.64, 122.55, 119.61, 87.96
(@CH2), 47.2 (br NCH3), 28.86 (CH(CH3)2), 27.20
(CH(CH3)2), 24.18 (CH(CH3)2) ppm. Anal. Calc.
(C23H35N4ClTi): C, 61.27; H, 7.84; N, 12.43. Found: C,
60.88; H, 7.89; N, 12.33%.
3.11. Synthesis of [CH2@C(C5H4N)(OAlMe3)-j2N,O]
AlMe2 (13)
Complex 3 (0.100 g, 0.210 mmol) was dissolved in
benzene (3.0 ml) and AlMe3 (0.15 g, 2.10 mmol) was
added. The solution was stirred at room temperature
overnight. All volatiles were completely removed under
high vacuum at room temperature. Pentane was added
and the solution was filtered over celite. White crystals
were deposited when the solution was stored at )30 °C.
The yield was 45 mg (43%). 1H NMR (C6D6): d 7.17 (d,
J ¼ 6:8 Hz, 1H, py-H6), 6.72 (td, J ¼ 6:8, 0.8 Hz, 1H,
py-H4), 6.62 (d, J ¼ 8:8 Hz, 1H, py-H3), 6.31 (t, J ¼ 6:4
Hz, 1H, py-H5), 5.56 (d, J ¼ 3:6 Hz, 1H, @CH2), 4.86
(d, J ¼ 3:6 Hz, 1H, @CH2), )0.04 (s, 9H, AlCH3), )0.27
(s, 6H, AlCH3) ppm. 13C{1H}NMR (C6D6) d 151.54,
150.37, 142.53, 140.59, 124.40, 120.30, 97.94 (@CH2),
)6.20 (br, AlC), )7.87 (br, AlC) ppm. Anal. Calc.
(C12H21NOAl2): C, 57.82; H, 8.51; N, 5.62. Found: C,
57.55; H, 8.15; N, 5.33%.
3.9. Synthesis of [(2,6-iPr2C6H3)NC(C5H4N)(@
CH2)]2Zr(NEt2)2 (11)
The complex was synthesized using the same proce-
dure and conditions for 9, but with ZrCl2(NEt2)2(THF)2
(0.707 g, 1.57 mmol) and the potassium salt 8 (1.00 g,
3.14 mmol). The solution was stirred for one day at
room temperature. The crystals, which were analytically
pure and suitable for X-ray crystallography, were ob-
tained by recrystallization in toluene at )30 °C. The
1
yield was 0.742 g (60%). H NMR (C6D6): d 8.70 (d,
J ¼ 5:6 Hz, 1H, py-H6), 7.50–7.24 (m, 4H), 6.76 (td,
J ¼ 7:2, 1.2 Hz, 1H, py-H5), 6.44 (t, J ¼ 6:4 Hz, 1H, py-
H4), 4.79 (s, 1H, @CH2), 4.11 (septet, J ¼ 6:8 Hz, 2H,
CH(CH3)2), 3.78 (s, 1H, @CH2), 3.43 (septet, J ¼ 6:8
Hz, 2H, CH(CH3)2), 3.33 (dq, J ¼ 14; 6.8 Hz, 2H,
NCH2), 2.77 (dq, J ¼ 14; 6.8 Hz, 2H, NCH2), 1.50 (d,
J ¼ 6:8 Hz, 3H, CH(CH3)2), 1.48 (d, J ¼ 6:8 Hz, 3H,
CH(CH3)2), 1.44 (d, J ¼ 6:8 Hz, 3H, CH(CH3)2), 1.34
(d, J ¼ 6:8 Hz, 3H, CH(CH3)2), 0.70 (t, J ¼ 7:2 Hz, 6H,
NCH2CH3) ppm. 13C{1H}NMR (C6D6) d 159.15,
156.34, 151.30, 147.61, 146.28, 144.65, 137.20, 124.96,
124.70, 124.19, 121.01, 120.85, 89.13 (@CH2), 43.42
(NCH2), 29.03, 28.00, 27.79, 27.43, 25.76, 24.65, 14.15
(NCH2CH3) ppm. Anal. Calc. (C46H66N6Zr): C,
69.56; H, 8.38; N, 10.58. Found: C, 69.43; H, 8.42; N,
10.21%.
3.12. Synthesis of [(2,6-iPr2C6H3)NC(C5H4N)(@
CH2)]AlMe2 (14)
The complex was synthesized using the same proce-
dure and conditions for 13, but with 11 (0.100 g, 0.126
mmol) and AlMe3 (0.024 ml, 0.252 mmol) in benzene
(1.0 ml). The solvent was removed by vacuum and the
residue was extracted with pentane. Light yellow single
crystals were deposited when the pentane solution was
stored at )30 °C overnight (20 mg, 24%).
1H NMR (C6D6): d 7.46 (d, J ¼ 5:6 Hz, 1H, py-H6),
7.19 (t, J ¼ 8:4 Hz, 1H, py-H3), 6.70 (ddd, J ¼ 8:0, 7.2,
1.2 Hz, 1H, py-H5), 6.26 (ddd, J ¼ 7:2, 5.2, 1.2 Hz, 1H,
py-H4), 4.55 (d, J ¼ 1:2 Hz, 1H, @CH2), 3.86 (d, J ¼ 1:2
Hz, 1H, @CH2), 3.58 (septet, J ¼ 7:2 Hz, 2H,
CH(CH3)2), 1.39 (d, J ¼ 7:2 Hz, 6H, CH(CH3)2), 1.36
(d, J ¼ 7:2 Hz, 6H, CH(CH3)2), )0.28 (s, 8H, AlCH3)
ppm. 13C{1H}NMR (C6D6) d 156.28, 150.26, 147.22,
142.68, 139.13, 126.24, 124.48, 122.90, 120.87, 84.26
(@CH2), 28.35, 26.41, 25.21, )8.49 (AlC) ppm. Anal.
Calc. (C21H29N2Al): C, 74.96; H, 8.71; N, 8.33. Found:
C, 74.62; H, 8.52; N, 8.45%.
3.10.
Synthesis
of
[(2,6-iPr2C6H3)NC(C5H4N)
(@CH2)]TiCl(NMe2)2 (12)
The complex was synthesized using the same proce-
dure and conditions for 9, but with TiCl2(NMe2)2 (0.325
g, 1.57 mmol) and the potassium salt 8 (1.00 g, 3.14
mmol). The solution was stirred for one day at room
temperature. The single crystals, which were analytically
pure, were obtained by recrystallization in toluene at
1
)30 °C. The yield was 0.445 g (63%). H NMR (C6D6):
d 8.52 (d, J ¼ 5:2 Hz, 1H, py-H6), 7.28–7.10 (m, 4H),

U.G. Joung et al. / Polyhedron 23 (2004) 1587–1594
1593
Table 1
Crystallographic parameters of 4, 11, 13 and 14a
4
11
13
14
Formula
Fw
Color
C
376.31
18H24N4O2Ti
C46H66N6Zr
794.27
yellow
C12H21Al2NO
249.26
C21H29AlN2
336.44
dark brown
0.3 ꢁ 0.3 ꢁ 0.15
8.3150(10)
13.9490(10)
17.1270(10)
90
pale yellow
0.20 ꢁ 0.15 ꢁ 0.15
8.865(3)
pale yellow
0.30 ꢁ 0.30 ꢁ 0.20
14.5650(10)
8.617(2)
17.395(2)
90
Size (mm)
ꢀ
0.20 ꢁ 0.20 ꢁ 0.15
12.6440(10)
17.6100(10)
20.0200(10)
90
a (A)
ꢀ
b (A)
9.262(3)
ꢀ
c (A)
10.200(2)
78.869(17)
88.652(18)
73.658(10)
788.1(4)
a (°)
b (°)
c (°)
97.476(3)
90
90
90
106.349(6)
90
3
ꢀ
V (A )
1969.6(3)
monoclinic
P21=c
1.269
4
0.452
4457.7(5)
orthorhombic
P212121
1.184
2094.9(6)
monoclinic
P21=N
1.067
4
0.101
Crystal system
Space group
Dcalc (g cmꢂ3
triclinic
ꢁ
P1
1.050
)
Z
4
0.283
2
l (mmꢂ1
)
0.168
2699
1643
151
Number of data collected
Number of unique data
Number of variables
R (%)
Rw(%)
Goodness-of-fit
8080
4418
10,110
10,110
8672
3115
230
0.0587
491
0.0442
224
0.1573
0.0811
0.2321
1.329
0.1029
1.010
0.0942
1.029
0.3676
1.230
P
P
P
a Data collected at 293(2) K with Mo Ka radiation (k (Ka) ¼ 0.7107), RðF Þ ¼ kFoj ꢂ jFck= jFoj with Fo > 2:0rðIÞ, Rw ¼ ½ ½wðFo2ꢂ
P
2
2 1=2
Fc2Þ ꢃ= ½wðFo2Þ ꢃ with Fo > 2:0rðIÞ.
3.13. Crystallographic studies
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