Nucleophilic attack toward group 4 metal complexes bearing reactive 1-aza-1,3-butadienyl and imido moieties

Article abstract of DOI:10.1021/ic0620844

Unique (1-aza-2-butenyl)titanium complexes bearing a phosphonium ylide moiety [Ti=NTbt{C(Me)(PR₃)CH=C(Me)N-(Mes)}CI] (3-5, Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Mes = 2,4,6-trimethylphenyl) were formed by the nucleophilic attack of PMe₃, P(n-Bu)₃, and 1,2-bis(dimethylphosphino)ethane (dmpe) toward the corresponding (1-aza-1,3-butadienyl)titanium complex, [Ti=NTbt{C(Me)CHC(Me)N(Mes)}(μ-Cl) ₂Li(tmeda)] (2a). The reaction of a lithium β-diketiminate, [Li{N(Tbt)C(Me)CHC(Me)N(Mes)}] (1) with [Ti^IICl₂(dmpe) ₂] also resulted in the formation of the same complex 5. Density functional theory calculation indicated that the negative charge of the model molecule of 3 was slightly delocalized to the C₃N plane. In addition, the calculation of the model molecule of 2a suggested the electrophilicity of 2a at the carbon atom connecting to the titanium atom. Interestingly, the reaction of zirconium and hafnium analogues (2b and 2c) with PMe₃ and dmpe did not proceed. In contrast to the cases of phosphine reagents, pyridine which was found to undergo the nucleophilic attack toward the titanium center of 2a gave the pyridine-coordinated titanium-imide [Ti=NTbt{C(Me)CHC(Me)N(Mes)} Cl(py)] (7).

Full text of DOI:10.1021/ic0620844

Inorg. Chem. 2007, 46, 1795−1802
Nucleophilic Attack toward Group 4 Metal Complexes Bearing Reactive
1-Aza-1,3-butadienyl and Imido Moieties
Hirofumi Hamaki, Nobuhiro Takeda, and Norihiro Tokitoh*
Institute for Chemical Research, Kyoto UniVersity, Gokasho, Uji, Kyoto 611-0011
Received November 1, 2006
Unique (1-aza-2-butenyl)titanium complexes bearing a phosphonium ylide moiety [TidNTbt{C(Me)(PR3)CHdC(Me)N-
(Mes)
nucleophilic attack of PMe3, P(n-Bu)3, and 1,2-bis(dimethylphosphino)ethane (dmpe) toward the corresponding (1-
aza-1,3-butadienyl)titanium complex, [Ti NTbt C(Me)CHC(Me)N(Mes) -Cl)2Li(tmeda)] (2a). The reaction of a
lithium -diketiminate, [Li N(Tbt)C(Me)CHC(Me)N(Mes)
] (1) with [TiIICl2(dmpe)2] also resulted in the formation of
}Cl] (3−5, Tbt ) 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Mes ) 2,4,6-trimethylphenyl) were formed by the
d
{
}(µ
â
{
}
the same complex 5. Density functional theory calculation indicated that the negative charge of the model molecule
of 3 was slightly delocalized to the C3N plane. In addition, the calculation of the model molecule of 2a suggested
the electrophilicity of 2a at the carbon atom connecting to the titanium atom. Interestingly, the reaction of zirconium
and hafnium analogues (2b and 2c) with PMe3 and dmpe did not proceed. In contrast to the cases of phosphine
reagents, pyridine which was found to undergo the nucleophilic attack toward the titanium center of 2a gave the
pyridine-coordinated titanium-imide [TidNTbt{C(Me)CHC(Me)N(Mes)}Cl(py)] (7).
Introduction
workers6 and Stephan and co-workers7 reported that the
reductions of the â-diketiminato complexes of Zr(IV) and
Ti(III) gave their respective ring-contracted imido complexes
(Scheme 1, eqs 1-3). Furthermore, Stephan and co-workers
reported that one-electron reduction of a [Ti{[DipNC-
(Me)]2CH}Cl(η5-C5H5)] under N2 atmosphere resulted in the
formation of a N2-activated â-diketiminato complex having
putative Ti(II) centers (Scheme 1, eq 4).
Recently, much attention has been paid to the chemistry
of â-diketiminato ligands bearing bulky substituents, such
as a 2,6-diisopropylphenyl (Dip) group on the nitrogen
atoms.1 One of the interesting properties of these ligands is
that they can stabilize low-valent transition metal and main-
group metal complexes.2 However, â-diketiminato complexes
of low-valent early transition metals have been little inves-
tigated to date. In general, it is difficult to prepare divalent
group 4 metal complexes because they are thermally unstable
and immediately react with unsaturated substrates (e.g., Ct
C,3 CdO,3 NdN,4 NtN,5,7 etc.). Recently, Mindiola and co-
On the other hand, we have reported the synthesis and
structure of an unsymmetrical, extremely bulky lithium
â-diketiminate, [Li{N(Tbt)C(Me)CHC(Me)N(Mes)}] (1, Tbt
) 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Mes ) 2,4,6-
trimethylphenyl).8 In addition, independently of the studies
reported by Mindiola and co-workers6 and Stephan and co-
* To whom correspondence should be addressed. E-mail: tokitoh@
boc.kuicr.kyoto-u.ac.jp.
(1) Bourget-Merle, L.; Lappert, M. F.; Severn, J. R. Chem. ReV. 2002,
(5) (a) MacLachlan, E. A.; Fryzuk, M. D. Organometallics 2006, 23,
1530-1543. (b) Manriquez, J. M.; Sanner, R. D.; Marsh, R. E.;
Bercaw, J. E. J. Am. Chem. Soc. 1976, 98, 3042-3044. (c) Duchateau,
R.; Gambarotta, S.; Beydoun, N.; Bensimon, C. J. Am. Chem. Soc.
1991, 113, 8986-8988. (d) Hanna, T. E.; Keresztes, I.; Lobkovsky,
E.; Bernskoetter, W. H.; Chirik, P. J. Organometallics 2004, 23, 3448-
3458.
(6) (a) Basuli, F.; Kilgore, U. J.; Brown, D.; Huffman, J. C.; Mindiola,
D. J. Organometallics 2004, 23, 6166-6175. (b) Basuli, F.; Huffman,
J. C.; Mindiola, D. J. Inorg. Chim. Acta 2007, 360, 246-254.
(7) Bai, G.; Wei, P.; Stephan, D. W. Organometallics 2006, 25, 2649-
2655.
102, 3031-3065.
(2) (a) Smith, J. M.; Sadique, A. R.; Cundari, T. R.; Rodgers, K. R.; Lukat-
Rodgers, G.; Lachicotte, R. J.; Flaschenriem, C. J.; Vela, J.; Holland,
P. L. J. Am. Chem. Soc. 2006, 128, 756-769. (b) Holland, P. L.;
Cundari, T. R.; Perez, L. L.; Eckert, N. A.; Lachicotte, R. J. J. Am.
Chem. Soc. 2002, 124, 14416-14424. (c) Cheng, Y.; Hitchcock, P.
B.; Lappert, M. F.; Zhou, M. Chem. Commun. 2005, 752-754. (d)
Driess, M.; Yao, S.; Brym, M.; van Wu¨llen, C.; Lentz, D. J. Am. Chem.
Soc. 2006, 128, 9628-9629.
(3) (a) Eisch, J. J. J. Organomet. Chem. 2001, 617-618, 148-157. (b)
Eisch, J. J.; Shi, X.; Lasota, J. Z. Naturforsch., B: Chem. Sci. 1995,
50, 342-350.
(4) Duchateau, R.; Williams, A. J.; Gambarotta, S.; Chiang, M. Y. Inorg.
Chem. 1991, 30, 4863-4866.
(8) (a) Takeda, N.; Hamaki, H.; Tokitoh, N. Chem. Lett. 2004, 33, 134-
135. (b) Hamaki, H; Takeda, N.; Yamasaki, T.; Sasamori, T.; Tokitoh,
N. J. Organomet. Chem. 2007, 692, 44-54.
10.1021/ic0620844 CCC: $37.00
Published on Web 01/31/2007
© 2007 American Chemical Society
Inorganic Chemistry, Vol. 46, No. 5, 2007 1795

Hamaki et al.
Scheme 1. Reductions of Group 4 Metal â-Diketiminates
Scheme 2. Dianionic 1-Aza-2-butenyl and Neutral
1-Aza-1,3-butadiene Structure (Scholz’s Work)
Scheme 3. Nucleophilic Attack of Phosphines toward (1-Aza-1,3-
butadienyl)titanium Complex
workers,7 we have found that the two-electron reduction of
â-diketiminato complexes of Ti(IV), Zr(IV), and Hf(IV)
derived from the lithium â-diketiminate 1 also gave imido
complexes (2a-c) via a regioselective cleavage of the C-N
bond of the intermediate M(II) complexes (Scheme 1, eq
5).9 The complexes 2a-c have a monoanionic, planar 1-aza-
1,3-butadienyl ligand. Furthermore, the possibility of a Ti-
(II) intermediate was supported by the reaction of lithium
â-diketiminate (1) with [TiIICl2(tmeda)2]10 (tmeda ) Me2-
NCH2CH2NMe2), which resulted in the formation of the same
complex 2a (Scheme 1, eq 6).9
Although the group 4 metal complexes bearing a monoan-
ionic, planar 1-aza-1,3-butadienyl moiety are rather rare
species, some (1,3-butadienyl)metal complexes have been
shown to be important intermediates in the catalytic cyclo-
trimerization of alkynes and other catalytic transformations
as well as a number of stoichiometric organometallic
reactions.11 The (heterobutadienyl)metal complexes such as
monoazabutadienyl and diazabutadienyl complexes of group
4 metals can possibly activate the imine carbon atom toward
C-C coupling reactions (e.g., the 1,3-dipolar cycloaddition,12a
the ring expansion by use of electrophiles,12b etc.). Specif-
ically, Scholz and co-workers reported the titanium complex
bearing a dianionic, nonplanar 1-aza-2-butenyl structure
which is a more dominant electronic structure than the corres-
ponding neutral 1-aza-1,3-butadiene structure (Scheme 2).13
In addition, the MeLi-induced R-proton elimination of
(1-aza-2-butenyl)titanium complexes resulted in the forma-
tion of the corresponding titanium-carbene-ate complexes.14
However, the reactivity of (1-aza-1,3-butadienyl)metal com-
plexes (2a-c), which have a conjugation pattern different
from that of the Scholz complex, has not been disclosed yet.
In this report, we describe the nucleophilic attack of some
nucleophiles such as phosphines, pyridine, and a sulfide
(12) (a) Scholz, J.; Go¨rls, H. Inorg. Chem. 1996, 35, 4378-4382. (b)
Scholz, J.; Kahlert, S.; Go¨rls, H. Organometallics 1998, 17, 2876-
2884.
(13) Scholz, J.; Kahlert, S.; Go¨rls, H. Organometallics 2004, 23, 1594-
1603.
(9) Hamaki, H.; Takeda, N.; Tokitoh, N. Organometallics 2006, 25, 2457-
2464.
(10) Edema, J. J. H.; Duchateau, R.; Gambarotta, S.; Hynes, R.; Gabe, E.
Inorg. Chem. 1991, 30, 154-156.
(11) (a) Yasuda, H.; Tatsumi, K.; Nakamura, A. Acc. Chem. Res. 1985,
18, 120-126. (b) Shore, N. E. Chem. ReV. 1988, 88, 1081-1119.
(14) Kahlert, S.; Go¨rls, H.; Scholz, J. Angew. Chem., Int. Ed. 1998, 37,
1857-1861.
(15) (a) Vincent, A. T.; Wheatley, P. J. J. Chem. Soc., Dalton Trans. 1972,
617. (b) Amman, H.; Wheeler, G. L.; Watts, P. H., Jr. J. Am. Chem.
Soc. 1973, 95, 6158-6163. (c) Erker, G.; Czlsch, P.; Kru¨ger, C.;
Wallis, J. M. Organometallics 1985, 4, 2059-2060.
1796 Inorganic Chemistry, Vol. 46, No. 5, 2007

Nucleophilic Attack toward Group 4 Metal Complexes
Scheme 4. Reaction of 2a with 0.5 equiv of dmpe
Table 1. Selected Bond Lengths (Å) and Angles (deg)
toward the titanium, zirconium, and hafnium imides (2a-c)
bearing a 1-aza-1,3-butadienyl ligand. In these reactions, the
selective nucleophilic attack was found to take place depend-
ing on the soft-hard character of the nucleophiles, although
2a-c have many active sites such as the metal center, metal-
imido bond, metal-carbon bond, and metal-nitrogen (of
imine) bond.
5
2aa
7
Ti-N1
1.721(5)
2.209(5)
2.464(6)
2.450(6)
1.501(8)
1.355(8)
1.392(7)
1.952(5)
1.717(4)
2.192(5)
2.981(5)
2.994(5)
1.339(7)
1.448(7)
1.296(6)
2.202(4)
1.732(4), 1.733(4)
2.147(5), 2.165(5)
2.968(5), 2.967(5)
2.983(5), 2.997(5)
1.339(7), 1.338(7)
1.448(7), 1.451(7)
1.315(6), 1.301(6)
2.199(4), 2.223(4)
2.279(4), 2.251(4)
2.3348(16),
Ti-C1
Ti‚‚‚C2
Ti‚‚‚C3
C1-C2
C2-C3
C3-N2
Ti-N2
Ti-N3
Ti-Cl1,
Cl2
Results and Discussion
2.346(2)
2.4185(17),
2.4223(17)
175.1(3)
Nucleophilic Attack of Phosphorus Compounds toward
Titanium, Zirconium, and Hafnium Complexes (2a-c)
Bearing a 1-Aza-1,3-butadienyl Ligand. The reaction of
(1-aza-1,3-butadienyl)titanium (2a) with PMe3, P(n-Bu)3, and
dmpe (dmpe ) 1,2-bis(dimethylphosphino)ethane) resulted
in the formation of the corresponding (1-aza-2-butenyl)-
titanium complexes (3-5) bearing a phosphonium ylide
moiety, while the reaction of 2a with P(OMe)3, PPh3, and
PCy3 (Cy ) cyclohexyl) did not occur (Scheme 3). No
reactions of 2a with P(OMe)3, PPh3, nor PCy3 may be
interpreted in terms of their weak nucleophilicity and steric
hindrance. The reaction of 2a with 0.5 equiv of dmpe gave
no 2:1 adduct of 2a with dmpe but yielded a 1:1 mixture of
5 and 2a (Scheme 4). Moreover, the reaction of 2a with an
excess of dmpe afforded the same complex 5 together with
free dmpe.
2.3262(16)
166.1(3), 167.3(3)
76.12(17), 75.96(17)
Ti-N1-C6
C1-Ti-N2
173.9(4)
86.9(2)
75.50(16)
a Reference 9.
3
observed in an upfield region [δH ) 4.16 (d, JPH ) 19.4
1
Hz), δC1 ) 45.3 (d, JPC ) 61.5 Hz), δC2 ) 94.6, δC3
)
157.9] compared with the chemical shifts of the C1-C2H-
4
C3 part of 2a [δH ) 6.59 (q, JPH ) 1.4 Hz), δC1 ) 237.2,
δC2 ) 132.6, δC3 ) 180.8]. Specifically, the 13C NMR
chemical shift of C1 for 3 appeared at a much higher field
than that of 2a. The 31P{1H} NMR spectrum of 3 was
observed in 18.8 ppm. The reaction of 2a with P(n-Bu)3 also
resulted in the formation of the phosphonium-ylide analogue
4 in 40% yield [the characteristic chemical shifts in NMR
spectra of the P+-C1--C2H-C3 part {δH ) 4.54 (d, JPH
3
) 16.7 Hz), δP ) 27.1}], although the isolation of the ylide
The (1-aza-2-butenyl)titanium complexes (3-5) were
1
4 was unsuccessful. The H and 13C NMR spectra of 5
1
characterized by the H, 13C, and 31P NMR spectra and
elemental analysis. The 1H and 13C NMR spectra of 3 showed
that the chemical shifts of the P+-C1--C2H-C3 part were
showed the chemical shifts and the coupling constants of
the P+-C1--C2H-C3 part [δH ) 4.28 (d, 3JPH ) 18.2 Hz),
δC1 ) 45.6 (d, 1JPC ) 58.1 Hz), δC2 ) 94.6] as well as those
of 3 and 4. The 31P{1H} NMR spectrum of 5 exhibited two
3
3
signals [δP ) -45.1 (d, JPP ) 27 Hz) and 24.2 (d, JPP
)
27 Hz)]. The NMR studies suggest that the C3NTi rings of
Scheme 5. Other Route of the Synthesis of 5
Figure 1. ORTEP drawing of 5 (50% probability). The hydrogen atoms
and solvent molecules are omitted for clarity.
Inorganic Chemistry, Vol. 46, No. 5, 2007 1797

Hamaki et al.
Scheme 6. Possible Mechanism for the Formation of 5
Scheme 7. Reaction of Zirconium and Hafnium Complexes (2b and
2c) Bearing a 1-Aza-1,3-butadienyl Ligand with Phosphines
Table 2. Bond Lengths (Å) and Angles (deg) of the Optimized
Structures of 3′, 2′a, and 2′ba
3′ 5 (obs.)
2′a
2a (obs.)
2′b
2b (obs.)
M-N1
M-C1
1.710 1.721(5) 1.689
2.203 2.209(5) 2.174
1.502 1.501(8) 1.357
1.378 1.355(8) 1.453
1.394 1.392(7) 1.309
1.977 1.952(5) 2.224
2.350 2.346(2) 2.539
2.510
1.717(4)
2.192(5)
1.339(7)
1.448(7)
1.296(6)
2.202(4)
2.4185(17) 2.697 2.5429(8)
2.4223(17) 2.739 2.5481(8)
2.285(8)
2.348(8)
1.852 1.8534(16)
2.315 2.322(2)
1.360 1.347(3)
1.454 1.455(3)
1.312 1.301(3)
2.335 2.3233(17)
C1-C2
C2-C3
C3-N2
M-N2
M-Cl1
M-Cl2
Li1-Cl1
Li1-Cl2
3-5 are more negative than that of 2a, and the negative
charges of 3-5 are mainly located on the C1 atom. In UV-
vis spectra, the π-π* transitions of the C3N ligand of 3 and
5 [3, λmax ) 350 (ꢀ ) 11 000); 5, 349 nm (ꢀ ) 11 000)]
were red shifted compared with that of 2a [318 nm (ꢀ )
12 000)], which indicated some conjugation of the C3N
ligand.
The molecular structure of 5 was determined by X-ray
crystallographic analysis. The ORTEP drawing of 5 is shown
in Figure 1, and the selected bond lengths and angles are
summarized in Table 1.
One can find many differences between the structure of 5
and that of 2a as follows. First, the C3N ligand of 5 can be
considered to have the η4-coordinaton mode in contrast to
the η2-coordinaton mode for 2a. The Ti-C(ligand backbone)
distances of 5 [2.464(6) (Ti-C2) and 2.450(6) Å (Ti-C3)]
are still longer than those reported for the single Ti-C bond
(Ti-C: 1.97-2.21 Å)17 but much shorter than those of 2a
[2.981(5) (Ti-C2) and 2.994(5) Å (Ti-C3)]. The central
titanium atom of 5 deviates from the C3N plane by 1.3125-
(67) Å, although the five-membered C3NTi ring of 2a is
almost planar. Second, they differ from each other in the
bond alternating pattern of the C3NTi rings. In the case of
5, the lengths of C1-C2 and C3-N2 bonds are both close
to those of the corresponding single bonds, while those of
2a are within the range of the corresponding double bond
lengths.16 The C2-C3 bond lengths observed for 5 and 2a
are close to those of the C-C double and single bonds,
respectively. That is, the C3NTi rings of 5 and 2a can be
depicted mainly by the 1-titana-2-azacyclopenta-3-ene struc-
ture for 5 and 1-titana-2-azacyclopenta-2,4-diene one for 2a.
Although the bond alternating pattern of the C3N ligand of
5 is similar to that of Scholz et al.’s titanium complex
(Scheme 2),12b it is different from that of Mu¨ller et al’s 1-aza-
2.195
2.195
2.245 2.356(4)
2.247 2.362(4)
175.3 172.44(13)
M-N1-C6 177.9 173.9(4) 175.075 175.1(3)
C1-M-N2 87.6 86.9(2) 77.269 75.50(16) 73.7 72.53(7)
a Calculated at the RB3LYP/6-31G(d) level and the observed structures
of 5, 2a, and 2b.
1,3-butadienyl complexes of late transition metals having
almost equal C1-C2 and C2-C3 bond lengths.18 The Ti-
N2 bond length of 5 is remarkably shorter than that of 2a.
The lengths of the Ti-C1 [2.209(5) Å] and Ti-N2 [1.952-
(5) Å] bonds for 5 are both within the range of the typical
single bond values (Ti-C, 1.97-2.21, and Ti-N, 1.93-
1.95 Å).17 The geometries around the C1 atom are pyramidal
for 5 as evidenced by the summation of the bond angles
around the C1 atom [338.3(5)°] in contrast to the trigonal
planar geometry of 2a. The C1-P1 bond length of 5 [1.751-
(6) Å] is longer than the typical phosphonium-ylide bond
length (1.63-1.72 Å),15 although it is slightly shorter than
the typical C-P single bond length (1.84-1.87 Å).16 In the
case of 5, there is no intermolecular contact between the P2
atom and the neighboring molecules (P2‚‚‚Ti* ) 3.52 Å).
Since a carbon atom connecting to a Ti(IV) atom with a
single bond is generally nucleophilic, it is very interesting
that the C1 atom in the C3NTi ring of 2a has electrophilicity.
An analogous nucleophilic attack of a phosphine to a carbon
atom connecting to a Ti(IV) atom bearing a dianionic 1,3-
butadienyl moiety has been reported by Rothwell and co-
workers.19 However, this reaction involves the migration of
a dimethylphenylsilyl substituent in one R-carbon to the other
R-carbon, and hence it differs from our system. Girolami
and co-workers reported that the reaction of [TiIIMe2(dmpe)2]
with trans,trans-1,4-diphenyl-1,3-butadiene results in the
displacement of one dmpe ligand and the generation of [TiII-
Chart 1
(16) Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen, A.
G.; Taylor, R. J. Chem. Soc., Perkin Trans. 1987, S1-S19.
(17) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson, D.
G.; Taylor, R. J. Chem. Soc., Perkin Trans. 1989, S1-S83.
(18) tom Dieck, H.; Stamp, L.; Diercks, R.; Mu¨ller, C. NouV. J. Chim.
1985, 9, 289.
(19) Balaich, G. J.; Fanwick, P. E.; Rothwell, I. P. Organometallics 1994,
13, 4117-4118.
1798 Inorganic Chemistry, Vol. 46, No. 5, 2007

Nucleophilic Attack toward Group 4 Metal Complexes
Table 3. Mulliken Atomic Charges of 3′, 2′a, and 2′b
atomic number
3′ (M ) Ti)
2′a (M ) Ti)
2′b (M ) Zr)
M
0.851
-0.361
-0.244
0.330
-0.741
-0.645
-0.469
0.897
-0.088
-0.193
0.422
-0.593
-0.673
-0.363
-0.378
1.319
-0.144
-0.180
0.387
-0.628
-0.657
-0.626
-0.638
C1
C2
C3
N1
N2
Cl1
Cl2
P1
0.745
Li1
0.349
0.555
Figure 2. LUMOs of 2′a and 2′b.
Scheme 8. Resonance Structure of (1-Aza-2-butenyl)titanium
Complexes (3-5)
Scheme 9. Nucleophilic Attack of Nitrogen and Sulfur Compounds
toward (1-Aza-1,3-butadienyl)titanium Complex
Me2(η4-1,4-C4H4Ph2)(dmpe)].20 In this reaction, the nucleo-
philic attack of dmpe did not proceed toward the carbon atom
connecting to the Ti(II) atom, although a free dmpe existed.
One- or two-electron reduction reactions of trivalent or
tetravalent titanium â-diketiminates in the presence of dmpe
were also found to result in the formation of the phosphonium
ylide 5 (Scheme 5). In addition, the reaction of 1 with [TiCl2-
(dmpe)2]21 allowed the same complex 5 in 60% yield
(Scheme 5). Taking these results into consideration, the
formation of 5 is most likely explained in terms of the initial
generation of the corresponding divalent titanium complexes,
[TiIICl{N(Tbt)C(Me)CHC(Me)N(Mes)}(dmpe)n] (6), fol-
lowed by the ring contraction reaction and the subsequent
nucleophilic attack of the P atom of dmpe to the C1 atom
(Scheme 6).
By contrast to the case of the titanium complex (2a), no
reactions were observed for the zirconium (2b) and hafnium
analogues (2c) when they were treated with dmpe and PMe3
in benzene at 80 °C (Scheme 7). The reasons for no
nucleophilic attack toward the zirconium and hafnium
complexes will be described later.
DFT Calculations of Mulliken Atomic Charges. The
density functional theory (DFT) calculations of titanium
imides 3′ and 2′a and zirconium analogue 2′b, where the
Tbt, Mes, dmpe, and Li(tmeda) parts of 5, 2a, and 2b were
substituted by 2,6-dimethylphenyl (Dmp), Dmp, PMe3, and
Li, respectively, were carried out at the RB3LYP level using
the 6-31G(d) basis set, except using the LANL2DZ basis
set on the Zr atom (Chart 1).
The Mulliken atomic charges of 3′ and 2′a (Table 3)
showed important differences from each other. That is, the
more negative charge population was located in the C3NTi
ring of 3′ rather than in that of 2′a (the sum of the charges
of the ring atoms: -0.165 for 3′, 0.365 for 2′a), and the
negative charge population of 3′ was localized particularly
on the C1 atom (-0.361 for 3′, -0.088 for 2′a).
These calculations on the charge population of 3′ indicated
the large contribution of resonance structure A, where the
negative charge is on the C1 atom, and a little contribution
of structures B and C, where the negative charges are on
the N2 and the C2 atoms, respectively (Scheme 8).
Scholz and co-workers reported the reaction of the (1-
aza-2-butenyl)titanium complex with MeLi, and LiI afforded
the titanium-carbene-ate complex [Ti-C(neighboring): 1.958-
(3) Å] with an emission of CH4.14 Rothwell and co-workers
also reported that the reaction of the (cyclohexyl-condensed
1,3-butadiene)titanium complex with PMe3 resulted in the
formation of the short Ti-C bond [1.956(7) Å].19 However,
the Ti-C1 bond of the (1-aza-2-butenyl)titanium complex
5 [2.209(5) Å] may not be classified as the above-mentioned
titanium-carbene bond but as the intermediate between the
single and the dative bonds shown in Scheme 8. Thus, the
unique structure of the monoanionic, 1-aza-2-butenyl ligand
of 5 was examined in detail by X-ray structural analysis and
DFT calculations.
DFT Calculations of Molecular Orbitals. In the DFT
calculations, the lowest unoccupied molecular orbital (LUMO)
of 2′a mainly consists of the dz2 orbital of the Ti atom, which
interacts with the px orbitals of the C1 and N2 atoms (Figure
2a). The nucleophilic attack of phosphines to the C1 atom
in the reaction of 2a is most likely interpreted in terms of
the large contribution of the px orbital of the C1 atom to the
LUMO. The nucleophilic attack to the N2 atom does not
take place probably because of the negative charge and the
The optimized structures of the C3NM rings of 3′, 2′a,
and 2′b are very similar to those of the C3NM rings of 5,
2a, and 2b experimentally obtained by X-ray structural
analysis, indicating that the calculated results should be
consistent with the properties of 5, 2a, and 2b (Table 2).
(20) Spencer, M. D.; Wilson, S. R.; Girolami, G. S. Organometallics 1997,
16, 3055-3067.
(21) (a) Girolami, G. S.; Wilkinson, G.; Galas, A. M. R.; Thornton-Pett,
M.; Hursthouse, M. B. J. Chem. Soc., Dalton Trans. 1985, 1339-
1348. (b) Simpson, C. Q., II; Hall, M. B.; Guest, M. F. J. Am. Chem.
Soc. 1991, 113, 2898-2903.
Inorganic Chemistry, Vol. 46, No. 5, 2007 1799

Hamaki et al.
attack of PMe3, P(n-Bu)3, and dmpe toward the (1-aza-1,3-
butadienyl)titanium complex 2a. The reaction of the lithium
â-diketiminate 1 with [TiCl2(dmpe)2] also resulted in the
formation of the same complex 5. The DFT calculation
indicated that the negative charge in the ylide complex was
mainly presented at the C1 atom and slightly delocalized to
the C3N plane. In addition, the calculation for the (1-aza-
1,3-butadienyl)titanium system suggested the high electro-
philicity at the C1 atom. On the other hand, the reactions of
the zirconium and hafnium analogues 2b,c with dmpe and
PMe3 did not proceed probably because of the more negative
charge of the C1 atoms of the (1-aza-1,3-butadienyl)metal
system, which were indicated by the Mulliken atomic charge
calculations. Pyridine underwent the nucleophilic attack
toward 2a at the titanium center rather than the C1 atom,
which reflected the hard character of pyridine. The investiga-
tions on the reactivities of 2a toward other nucleophiles are
currently in progress.
Figure 3. ORTEP drawing of 7 (50% probability). The hydrogen atoms
and solvent molecules are omitted for clarity. One of the two independent
molecules in the unit cell is depicted.
steric hindrance at the N2 atom, although the p orbital of
the N2 atom has a similarly large contribution to the LUMO.
In the case of zirconium, the px orbitals of the C1 and N2
atoms have a similarly large contribution to the LUMO
(Figure 2b). However, the Mulliken atomic charge analysis
showed important differences between 2′a and 2′b; that is,
the more negative charge population was observed for the
C1 atom of 2′b (-0.144) than that of 2′a (-0.088, Table
3). For this reason, the reactions of the zirconium and
hafnium complexes (2b and 2c) with dmpe and PMe3 might
not take place.
Experimental Section
General Considerations. Unless otherwise stated, all operations
were performed in an MBRAUN Labmaster glovebox under an
atmosphere of purified argon. Celite was activated at 200 °C under
vacuum for 1 day. [Li{TbtNC(Me)CHC(Me)NMes}] (1),8 [TiCl2-
(dmpe)2],21 [TiCl2(py)4],22 [TiCln{TbtNC(Me)CHC(Me)NMes}] (n
) 2, 3),9 and [MdNTbt{C(Me)CHC(Me)N(Mes)}(µ-Cl)2Li(tmeda)]
(2a-c)9 were prepared according to the methods described in the
literature. 1H NMR (300 MHz), 13C NMR (75 MHz), and 31P NMR
(121 MHz) spectra were recorded on a JEOL JNM AL-300
Nucleophilic Attack of Nitrogen and Sulfur Com-
pounds toward (1-Aza-1,3-butadienyl)titanium Complex.
The unique reactivity of the (1-aza-1,3-butadienyl)titanium
complex 2a prompted us to investigate the reactions of 2a
with nitrogen and sulfur compounds. Although the reactions
of 2a with NEt3 and SMe2 did not occur, the reaction of 2a
with pyridine resulted in the formation of the pyridine-
coordinated titanium-imide 7 with the removal of LiCl-
(tmeda) (Scheme 9). That is, the nucleophilic attack of
pyridine toward the titanium center rather than the C1 atom
was due to the hard character of pyridine. The reaction of 1
with [TiIICl2(py)4]22 also gave the same complex 7.
1
spectrometer. The H NMR chemical shifts were reported with
reference to the internal residual C6D5H (7.15 ppm). The 13C NMR
chemical shifts were reported with reference to the carbon-13 signal
of C6D6 (128.0 ppm). Multiplicity of signals in 13C NMR spectra
was determined by DEPT techniques. The 31P NMR chemical shifts
were reported with reference to the external standards, 85% H3-
PO4 (0 ppm). Electronic spectra were recorded on a JASCO V-570
UV-vis spectrometer. Melting points were determined on a Yanaco
micro melting point apparatus and are uncorrected. Elemental
analyses were carried out at the Microanalytical Laboratory of the
Institute for Chemical Research, Kyoto University.
1
Complex 7 was reasonably characterized by the H and
13C NMR spectra and elemental analysis, and its molecular
structure was definitively determined by X-ray structural
analysis (Figure 3 and Table 1). The 13C NMR chemical shift
of C1 for 7 is observed at a high field (237.1 ppm).
Reaction of [TidNTbt{C(Me)CHC(Me)N(Mes)}(µ-Cl)2Li-
(tmeda)] (2a) with PMe3. PMe3 (93 µL, 900 µmol) was added to
a solution of 2a (300.1 mg, 297.5 µmol) in benzene (8 mL). The
reaction mixture was stirred for 3 h at room temperature, and the
solvent was removed under reduced pressure. Benzene was added
to the red residue, and the filtration through Celite gave a dark red
solution. The filtrate was dried under vacuum, and the product was
recrystallized from toluene at -40 °C yielding the almost pure
product as dark red crystals [TidNTbt{C(Me)(PMe3)CHdC(Me)N-
Two independent molecules are found in the unit cell of
7, and both molecules have structures essentially similar to
each other, except for the orientation of the pyridine ring to
the TiC3N plane [dihedral angles between the TiC3N and
pyridine planes are 87.9(4) and 68.4(4)°, respectively]. The
Ti-N1 distances of 7 [1.732(4), 1.733(4) Å] are close to
those of imido complexes 5 and 2a. The C3NTi ring of 7 is
almost planar. Thus, the C3NTi ring of 7 is consistent with
that of 1-titana-2-azacyclopenta-2,4-diene as well as 2a.
1
(Mes)}Cl] (3, 272.7 mg, 99%). 3: mp 213.4-216.3 °C (dec). H
NMR (300 MHz, C6D6, 25 °C): δ 0.24 (s, 36H), 0.43 (s, 18H),
2
3
0.79 (d, JPH ) 12.7 Hz, 9H), 1.43 (s, 1H), 1.54 (d, JPH ) 20.3
Hz, 3H), 1.85 (s, 3H), 2.20 (s, 3H), 2.40 (s, 3H), 2.84 (s, 3H), 3.58
3
(br s, 1H), 3.98 (br s, 1H), 4.16 (d, JPH ) 18.2 Hz, 1H), 6.47 (br
s, 1H), 6.59 (br s, 1H), 6.87 (s, 1H), 6.90 (s, 1H). 13C{1H} NMR
Conclusion
(75 MHz, C6D6, 25 °C): δ 1.07 (CH3), 1.37 (CH3), 10.0 (d, 1JPC
)
57.2 Hz, CH3), 15.1 (CH3), 20.0 (CH3), 20.8 (CH3), 21.0 (CH3),
21.2 (CH), 22.2 (CH), 22.5 (CH3), 29.8 (CH), 45.3 (d, 1JPC ) 61.5
Hz), 94.6 (CH), 121.6 (CH), 126.4 (CH), 129.6 (CH), 130.07 (CH),
130.13, 132.4, 132.5, 137.7, 138.1, 142.9, 143.2, 147.0, 157.9. 31P-
{1H} NMR (121 MHz, C6D6, 25 °C): δ 18.8 (s). UV-vis
The (1-aza-2-butenyl)titanium complexes (3-5) bearing
a phosphonium ylide moiety were formed by the nucleophilic
(22) Araya, M. A.; Cotton, F. A.; Matonic, J. H.; Murillo, C. A. Inorg.
Chem. 1995, 34, 5424-5428.
1800 Inorganic Chemistry, Vol. 46, No. 5, 2007

Nucleophilic Attack toward Group 4 Metal Complexes
(n-hexane): λmax 280 (ꢀ, 1.9 × 104), 350 (ꢀ, 1.1 × 104), 469 (2.8
× 103) nm. Anal. Calcd for C44H86N2Si6PClTi: C, 57.07; H, 9.36;
N, 3.03. Found: C, 57.34; H, 9.27; N, 3.31.
was degassed and sealed, the measurement of the 1H NMR spectrum
revealed that the reaction did not proceed. After the sealed tube
was heated at 60 °C for 2 days, the measurement of the H NMR
1
spectrum revealed the formation of a mixture of 5 and 1 (60:40
5/1).
Reaction of 2a with P(n-Bu)3. To a mixture of 2a (99.9 mg,
99.2 µmol) and P(n-Bu)3 (75 µL, 300 µmol) in a NMR tube was
added 0.6 mL of C6D6. After the NMR tube was sealed, degassed,
One-Electron Reduction of [TiCl2{TbtNC(Me)CHC(Me)-
NMes}] with KC8. KC8 (11.8 mg, 87.0 µmol) was added to a
solution of [TiCl2{TbtNC(Me)CHC(Me)NMes}] (70.0 mg, 79.1
µmol) in benzene (2 mL) and dmpe (17 µL, 100 µmol). The reaction
mixture was stirred for 1 day at room temperature, and the solvent
was removed under reduced pressure. Benzene was added to the
red residue, and the filtration through Celite gave a dark red
solution. The filtrate was evaporated under vacuum, and the residual
product was recrystallized from toluene at -40 °C, yielding the
almost pure product 5 (64.0 mg, 81%) as dark red crystals.
1
and heated at 80 °C for 2 days, the measurement of the H NMR
spectrum revealed that the reaction proceeds to form [Ti{C(Me)-
{P(n-Bu)3}CHdC(Me)N(Mes)}Cl(NTbt)] 4 (ca. 40% in NMR
yield). 4: 1H NMR (300 MHz, C6D6, 25 °C): δ 0.14 (s, 36H),
0.14 (s, 18H), 0.15 (s, 18H), 0.19 (s, 18H), 0.88 (m, 6H), 1.30-
1.40 (m, 1 + 18H), 1.81 (s, 3H), 2.18 (s, 3H), 2.35 (s, 3H), 2.82
3
(s, 3H), 3.90 (br, 2H), 4.54 (d, JPH ) 16.7 Hz), 6.42-6.48 (br,
2H), 6.82 (s, 2H). 31P{1H} NMR (121 MHz, C6D6, 25 °C): δ 27.1
(s).
Reaction of 2a with dmpe (1.0 equiv). dmpe (17 µL, 100 µmol)
was added to a solution of 2a (100.1 mg, 99.16 µmol) in benzene
(2 mL). The reaction mixture was stirred for 3 h at room
temperature, and the solvent was removed under reduced pressure.
Benzene was added to the red residue, and the filtration through
Celite gave a dark red solution. The filtrate was evaporated under
vacuum, and the residual product was recrystallized from toluene
at -40 °C, yielding the almost pure product 5 (97.2 mg, 98%) as
dark red crystals. 5: mp 264.2-267.3 °C (dec). 1H NMR (300 MHz,
Two-Electron Reduction of [TiCl3{TbtNC(Me)CHC(Me)-
NMes}] with KC8. KC8 (19.4 mg, 144 µmol) was added to a
solution of [TiCl3{TbtNC(Me)CHC(Me)NMes}] (60.1 mg, 65.3
µmol) in benzene (2 mL) and dmpe (17 µL, 100 µmol). The reaction
mixture was stirred for 1 day at room temperature, and the solvent
was removed under reduced pressure. Benzene was added to the
red residue, and the filtration through Celite gave a dark red
solution. The filtrate was evaporated under vacuum, and the residual
product was recrystallized from toluene at -40 °C, yielding the
almost pure product 5 (54.2 mg, 83%) as dark red crystals.
2
C6D6, 25 °C): δ 0.22 (s, 36H), 0.41 (s, 18H), 0.72 (d, JPH ) 4.0
Hz, 6H), 1.02 (d, 2JPH ) 12.5 Hz, 6H), 1.18-1.28 (m, 2H + 2H),
Reactions of [ZrdNTbt{C(Me)CHC(Me)N(Mes)}(µ-Cl)2Li-
(tmeda)] (2b) and [HfdNTbt{C(Me)CHC(Me)N(Mes)}(µ-Cl)2Li-
(tmeda)] (2c) with PMe3 and dmpe. To mixtures of 2b (52.6 mg,
50.0 µmol) and PMe3 (16 µL, 150 µmol), 2b (52.6 mg, 50.0 µmol)
and dmpe (9 µL, 60 µmol), 2c (57.0 mg, 50.0 µmol) and PMe3 (16
µL, 150 µmol), and 2c (57.0 mg, 50.0 µmol) and dmpe (9 µL,
60.0 µmol) in NMR tubes was added 0.6 mL of C6D6. After the
NMR tubes were degassed, sealed, and heated at 80 °C for 2 days,
3
1.41 (s, 1H), 1.62 (d, JPH ) 19.6 Hz, 3H), 1.83 (s, 3H), 2.18 (s,
3H), 2.40 (s, 3H), 2.81 (s, 3H), 3.63 (br s, 1H), 3.99 (br s, 1H),
4.28 (d, 3JPH ) 18.2 Hz, 1H), 6.46 (br s, 1H), 6.57 (br s, 1H), 6.84
(s, 1H), 6.89 (s, 1H). 13C{1H} NMR (75 MHz, C6D6, 25 °C): δ
1
4
1.4 (CH3), 2.1 (CH3), 8.5 (dd, JPC ) 58.1 Hz, JPC ) 19.4 Hz,
CH3), 13.7 (dd, 1JPC ) 15.1 Hz, 4JPC ) 5.6 Hz, CH3), 15.7 (CH3),
20.5 (CH3), 20.8 (dd, 1JPC ) 47.5 Hz, 2JPC ) 15.2 Hz, CH2), 21.15
(CH3), 21.4 (CH3), 21.6 (CH), 22.8 (CH3), 23.0 (CH), 24.1 (dd,
1
the measurement of the H NMR spectra revealed the reactions
2
1
1JPC ) 18.0 Hz, JPC ) 6.5 Hz, CH2), 30.1 (CH), 45.6 (d, JPC
)
did not proceed.
58.1 Hz), 95.2 (CH), 121.6 (CH), 126.5 (CH), 129.6 (CH), 130.08
Reaction of 2a with Pyridine. Pyridine (40 µL, 496 µmol) was
added to a solution of 2a (100.2 mg, 99.2 µmol) in benzene (2
mL). The reaction mixture was stirred for 3 h at room temperature,
and the solvent was removed under reduced pressure. Benzene was
added to the red residue, and the filtration through Celite gave a
dark red solution. The filtrate was dried under vacuum, and the
product was recrystallized from toluene at -40 °C, yielding the
almost pure product as dark red crystals [TidNTbt{C(Me)CHC-
(Me)N(Mes)}Cl(py)] (7, 84.8 mg, 92%). 7: mp 162-164 °C (dec).
1H NMR (300 MHz, C6D6, 25 °C): δ 0.16 (s, 18H), 0.21 (s, 18H),
0.28 (s, 18H), 1.44 (s, 1H), 1.48 (s, 3H), 2.07 (s, 6H), 2.09 (s, 3H),
2.22 (d, 4JHH ) 1.3 Hz, 3H), 2.87 (br s, 1H), 2.93 (br s, 1H), 6.47
(CH), 130.14, 132.46, 132.49, 137.7, 138.1, 142.7, 143.0, 146.9,
3
157.9. 31P{1H} NMR (121 MHz, C6D6, 25 °C): δ -45.1 (d, JPP
3
) 27 Hz), 24.2 (d, JPP ) 27 Hz). UV-vis (n-hexane): λmax 281
(ꢀ, 1.9 × 104), 349 (1.1 × 104), 463 (2.8 × 103) nm. Anal. Calcd
for C47H93N2Si6PClTi: C, 56.45; H, 9.37; N, 2.80. Found: C, 56.19;
H, 9.53; N, 2.76.
Reactions of 2a with P(OMe)3, PPh3, and PCy3. To mixtures
of 2a (100.1 mg, 99.3 µmol) and P(OMe)3 (35 µL, 300 µmol), 2a
(40.0 mg, 39.7 µmol) and PPh3 (31.2 mg, 159 µmol), and 3a (40.0
mg, 39.7 µmol) and PCy3 (13.3 mg, 159 µmol) in NMR tubes was
added 0.6 mL of C6D6. After the NMR tubes were sealed, degassed,
1
and heated at 80 °C for 2 days, the measurement of the H NMR
4
(br s, 1H), 6.51 (br s, 1H), 6.57 (q, JHH ) 1.3 Hz, 1H), 6.67 (m,
spectra revealed that the reactions did not proceed.
2H), 6.73 (m, 1H), 8.86 (m, 2H). 13C{1H} NMR (75 MHz, C6D6):
δ 1.1 (CH3), 1.5 (CH3), 2.0 (CH3), 18.3 (CH3), 20.8 (CH3), 21.0
(CH3), 21.3 (CH), 22.3 (CH3), 29.4 (CH), 30.3 (CH), 124.1 (CH),
125.9 (CH), 128.9 (CH), 129.1 (CH), 130.5, 131.6 (CH), 132.5,
134.1, 134.9, 135.7 (CH), 136.6, 144.0, 151.1 (CH), 162.3, 199.0,
237.1. UV-vis (n-hexane): λmax 284 (ꢀ, 1.9 × 104), 319 (ꢀ, 1.2 ×
104), 410 (1.8 × 103) nm. Anal. Calcd for C46H82N3Si6ClTi: C,
59.47; H, 8.90; N, 4.52. Found: C, 59.11; H, 8.96; N, 4.63.
Reaction of 2a with dmpe (0.5 equiv). To a mixture of 2a
(199.9 mg, 199.1 µmol) and dmpe (17 µL, 100 µmol) in a NMR
tube was added 0.6 mL of C6D6. The NMR tube was sealed,
1
degassed, and heated at 80 °C for 2 days. The H NMR spectrum
showed the formation of a mixture of 5 and 2a (50:50 5/2a).
Reaction of 2a with dmpe (5.0 equiv). To a mixture of 2a (50.0
mg, 49.6 µmol) and dmpe (42 µL, 248 µmol) in a NMR tube was
added 0.6 mL of C6D6. The NMR tube was sealed and degassed.
The 1H and 31P NMR spectra showed the formation of 5 and a free
dmpe.
Reaction of [Li{TbtNC(Me)CHC(Me)NMes}] (1) with [TiCl2-
(dmpe)2]. To a mixture of 1 (40.1 mg, 51.7 µmol) and [TiCl2-
(dmpe)2] (28.2 mg, 67.2 µmol) in a NMR tube were added 0.3 mL
of C6D6 and 0.3 mL of tetrahydrofuran (THF). After the NMR tube
Reactions of 3a with NEt3 and SMe2. To mixtures of 3a (40.0
mg, 39.7 µmol) and NEt3 (199 µL, 200 µmol) and 3a (99.8 mg,
99.2 µmol) and SMe2 (36 µL, 500 µmol) in NMR tubes was added
0.6 mL of C6D6. After the NMR tubes were degassed, sealed, and
heated at 80 °C for 2 days, the measurement of the 1H NMR spectra
revealed the reactions did not proceed.
Inorganic Chemistry, Vol. 46, No. 5, 2007 1801

Hamaki et al.
Reaction of 1 with [TiCl2(py)4]. A solution of 1 (40.0 mg, 51.7
µmol) in benzene (2 mL) was added to [TiCl2(py)4] (29.2 mg, 67.4
µmol). The reaction mixture was stirred for 1 day at room
temperature, causing the change of dark blue color into dark red
color, and the solvent was removed under reduced pressure.
Benzene was added to the red residue, and the filtration through
Celite gave a dark red solution. The filtrate was dried under vacuum,
and the product was recrystallized from toluene at -40 °C yielding
the almost pure product as dark red crystals 7 (41.8 mg, 87%).
X-ray Crystallography. Single crystals of 5 and 7 were grown
by the slow evaporation of the saturated toluene/hexane solution
at -40 °C. The preparation of this sample consisted of coating the
crystal with silicon grease, mounting it on a glass fiber, and placing
it under a cold stream of N2 on the diffractometer. The intensity
data of 5 and 7 were collected on a Rigaku/MSC mercury charged-
coupled device (CCD) diffractometer with graphite monochromated
Mo KR radiation (λ ) 0.710 71 Å) to 2θmax ) 50° at 93 K. The
structures of 5 and 7 were solved by direct method (SIR97).23 All
crystallographic data were refined by a full-matrix least-squares
procedure on F2 for all reflections (SHELXL-97).24 All of the non-
hydrogen atoms of 5 and 7 were placed using AFIX instruction.
Crystal data for 5: C47H93ClN2P2Si6Ti‚C7H8, M ) 1092.20, triclinic,
space group P1h (No. 2), a ) 11.8582(13), b ) 16.745(2), c )
18.135(4) Å, R ) 98.209(17), â ) 101.840(15), γ ) 107.231(5)°,
V ) 3285.4(10) Å3, Z ) 2, Dcalcd ) 1.104 g cm-3, R1(I > 2σ(I)) )
0.0818, wR2 (all data) ) 0.1938, T ) 103(2) K, GOF ) 1.030.
CCDC 615 249. Crystal data for 7: C46H82ClN3Si6Ti‚0.5C6H14, M
) 972.12, triclinic, space group P1h (No. 2), a ) 12.368(5), b )
18.983(8), c ) 27.134(10) Å, R ) 106.011(4), â ) 90.942(2), γ
) 108.792(5)°, V ) 5758(4) Å3, Z ) 4, Dcalcd ) 1.121 g cm-3,R1(I
> 2σ(I)) ) 0.0868, wR2 (all data) ) 0.2276, T ) 103(2) K, GOF
) 1.112. CCDC 627 560.
Computational Methods. The geometries of [Ti{C(Me)(PMe3)-
CHdC(Me)N(Dmp)}Cl(NDmp)] (3′), [TidNDmp{C(Me)CHC-
(Me)N(Dmp)}(µ-Cl)2Li] (2′a), and [TidNDmp{C(Me)CHC(Me)N-
(Dmp)}(µ-Cl)2Li] (2′b) were optimized by using the Gaussian 98
program25 at RB3LYP/6-31G(d), except the LANL2DZ basis set
was used on the Zr atom.
Acknowledgment. This work was partially supported by
Grants-in-Aid for Scientific Research [Nos. 12CE2005,
17GS0207, 14078213, and 15750031] and the 21 COE
Program on Kyoto University Alliance for Chemistry from
the Ministry of Education, Culture, Sports, Science and
Technology, Japan. We are grateful to Dr. Takahiro Sasamori,
Institute for Chemical Research, Kyoto University, for
valuable discussions.
Supporting Information Available: Crystallographic informa-
tion files for 5 and 7, and Cartesian coordination and molecular
orbitals of the optimized structures for 3′, 2′a, and 2′b. This material
is available free of charge via the Internet at http://pubs.acs.org.
IC0620844
(25) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb,
M. A.; Cheeseman, J. R.; Zakrzewski, V. G.; Montgomery, J. A., Jr.;
Stratmann, R. E.; Burant, J. C.; Dapprich, S.; Millam, J. M.; Daniels,
A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J.; Barone,
V.; Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo, C.;
Clifford, S.; Ochterski, J.; Petersson, G. A.; Ayala, P. Y.; Cui, Q.;
Morokuma, K.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.;
Foresman, J. B.; Cioslowski, J.; Ortiz, J. V.; Stefanov, B. B.; Liu, G.;
Liashenko, A.; Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R.
L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara,
A.; Gonzalez, C.; Challacombe, M.; Gill, P. M. W.; Johnson, B. G.;
Chen, W.; Wong, M. W.; Andres, J. L.; Head-Gordon, M.; Replogle,
E. S.; Pople, J. A. Gaussian 98, revision A.6; Gaussian, Inc.:
Pittsburgh, PA, 1998.
(23) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G. L.; Giaco-
vazzo, C.; Guagliardi, A.; Moliterni, A. G. G.; Polidori, G.; Spagna,
R. J. Appl. Crystallogr. 1999, 32, 115-119.
(24) Sheldrick, G. M. SHELX-97, Program for the Refinement of Crystal
Structures; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
1802 Inorganic Chemistry, Vol. 46, No. 5, 2007