Synthesis and structure of (triphenylsilyl)imido complexes of titanium and zirconium

Article abstract of DOI:10.1021/om050179s

Titanium and zirconium (triphenylsilyl)imido complexes are available through transimination from the tert-butylimido complexes with H ₂NSiPh₃. The useful starting material Ti(NSiPh ₃)Cl₂(py)₂ (1) is prepared in 88% yield by treatment of Ti(NBu^t)Cl₂(py)₃ with H ₂NSiPh₃. Imido 1 is a dimer in the solid state with bridging chlorides; however, solution molecular weight studies indicate that 1 is a monomer in CH₂Cl₂. 1 reacts with 4,4′-di-tert-butyl-2,2′-bipyridine (bpy) to generate the pseudo-octahedral Ti(NSiPh₃)(bpy)(py)Cl₂ (2) in 74% recrystallized yield. Replacement of the chloride ligands of 1 with 2 equiv of Lidap, 1 equiv of Libap, or 1 equiv of Lipap afforded the pyrrolylimido complexes Ti(NSiPh₃)(dap)₂ (3), Ti(NSiPh ₃)(bap)Cl (4), and Ti(NSiPh₃)(pap)Cl (5), respectively. The reaction of 2 equiv of neophyl (Nph) magnesium bromide with 1 provided [Ti(μ-NSiPh₃)(Nph)₂]₂ (6) in 59% yield. The pseudo-octahedral complex Ti(NSiPh₃)(dpma)(bpy) (8) was available through addition of Li₂dpma to 1, forming Ti(NSiPh ₃)(dpma)(py)₂ (7) followed by treatment with bpy. Alternatively, 8 was prepared by addition of bpy and H₂NSiPh ₃ to Ti(NMe₂)₂(dpma). The zirconium tert-butylimido complex Zr(NBu^t)(dpma)(bpy) (9) was available in 43% yield by treatment of Zr(NMe₂)₂(py)(dpma) with bpy and H₂NBu^t. Transimination on 9 with H₂NSiPh ₃ provided the (triphenylsilyl)imido complex Zr(NSiPh ₃)(dpma)(bpy) (10) in 34% yield. In an unusual transformation, 10 reacts with excess sodium 2,6-dimethylphenoxide in THF to afford [Na(bpy)] [Zr(dpma)(OAr)₃] (11), where the Na coordinates to the bpy and both pyrrole rings of the dpma in an η⁵ fashion. Compounds 1, 5, 6, 8, and 11 were structurally characterized.

Full text of DOI:10.1021/om050179s

3272
Organometallics 2005, 24, 3272-3278
Synthesis and Structure of (Triphenylsilyl)imido
Complexes of Titanium and Zirconium
Yahong Li,† Sanjukta Banerjee, and Aaron L. Odom*
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
Received March 10, 2005
Titanium and zirconium (triphenylsilyl)imido complexes are available through transimi-
nation from the tert-butylimido complexes with H2NSiPh3. The useful starting material
Ti(NSiPh3)Cl2(py)2 (1) is prepared in 88% yield by treatment of Ti(NBut)Cl2(py)3 with
H2NSiPh3. Imido 1 is a dimer in the solid state with bridging chlorides; however, solution
molecular weight studies indicate that 1 is a monomer in CH2Cl2. 1 reacts with 4,4′-di-tert-
butyl-2,2′-bipyridine (bpy) to generate the pseudo-octahedral Ti(NSiPh3)(bpy)(py)Cl2 (2) in
74% recrystallized yield. Replacement of the chloride ligands of 1 with 2 equiv of Lidap, 1
equiv of Libap, or 1 equiv of Lipap afforded the pyrrolylimido complexes Ti(NSiPh3)(dap)2
(3), Ti(NSiPh3)(bap)Cl (4), and Ti(NSiPh3)(pap)Cl (5), respectively. The reaction of 2 equiv
of neophyl (Nph) magnesium bromide with 1 provided [Ti(µ-NSiPh3)(Nph)2]2 (6) in 59% yield.
The pseudo-octahedral complex Ti(NSiPh3)(dpma)(bpy) (8) was available through addition
of Li2dpma to 1, forming Ti(NSiPh3)(dpma)(py)2 (7) followed by treatment with bpy.
Alternatively, 8 was prepared by addition of bpy and H2NSiPh3 to Ti(NMe2)2(dpma). The
zirconium tert-butylimido complex Zr(NBut)(dpma)(bpy) (9) was available in 43% yield by
treatment of Zr(NMe2)2(py)(dpma) with bpy and H2NBut. Transimination on 9 with H2NSiPh3
provided the (triphenylsilyl)imido complex Zr(NSiPh3)(dpma)(bpy) (10) in 34% yield. In an
unusual transformation, 10 reacts with excess sodium 2,6-dimethylphenoxide in THF to
afford [Na(bpy)][Zr(dpma)(OAr)3] (11), where the Na coordinates to the bpy and both pyrrole
rings of the dpma in an η5 fashion. Compounds 1, 5, 6, 8, and 11 were structurally
characterized.
Introduction
The majority of silylimido complexes of the group 4
elements are the NSiBut3 complexes of Wolczanski and
co-workers, known to activate C-H bonds,5 and several
(trimethylsilyl)imido derivatives of titanium. The earli-
est report is by Bu¨rger and Wannagat, who proposed
the generation of Me3SiNdTiCl2(pyridine)2 in 1963.6,7
Dehnicke and co-workers reported the synthesis of an
organometallic trimethylsilyl derivative.8 Chirik and co-
workers reported a cyclopentadienyl-supported (tri-
methylsilyl)imido complex,9 and triazacyclononane de-
rivatives were used by the Mountford group.10 Benz-
Silylimido complexes are a mainstay of imido studies,
and there are a large number of (trialkylsilyl)imido
complexes known for the transition metals.1 Most
notably, terminal (trimethylsilyl)imido complexes are
known for all the elements of groups 4-6.1 In addition,
Wolczanski and co-workers have prepared and studied
the reaction chemistry of many (tri-tert-butylsilyl)imido
complexes.2 Surprisingly, (triarylsilyl)imido complexes
of the transition metals have scarcely appeared in the
literature, and there are none with titanium and
zirconium.3 Consequently, we sought, as a continuation
of our interest in titanium imido reactivity,4 to develop
routes to these complexes.
(5) (a) Cundari, T. R.; Klickman, T. R.; Wolczanski, P. T. J. Am.
Chem. Soc. 2002, 124, 1481. (b) Slaughter, L. M.; Wolczanski, P. T.;
Klinckman, T. R.; Cundari, T. R. J. Am. Chem. Soc. 2000, 122, 7953.
(c) Bennett, J. L.; Vaid, T. P.; Wolczanski, P. T. Inorg. Chem. Acta 1998,
270, 414. (d) Bennett, J. L.; Wolczanski, P. T. J. Am. Chem. Soc. 1997,
119, 10696. (e) Bennett, J. L.; Wolczanski, P. T. J. Am. Chem. Soc.
1994, 116, 2179. (f) Cummins, C. C.; Schaller, C. P.; Van Duyne, G.
D.; Wolczanski, P. T.; Chan, A. W. C.; Hoffmann, R. J. Am. Chem. Soc.
1991, 113, 2985.
* To whom correspondence should be addressed. E-mail: odom@
cem.msu.edu.
† Current address: Suzhou University, School of Chemistry and
Chemical Engineering, No. 1, Shizi St., Suzhou, China.
(1) For a review of imido chemistry see: Wigley, D. E. Prog. Inorg.
Chem. 1994, 42, 239.
(6) Bu¨rger, H.; Wannagat, U. Monatsh. Chem. 1963, 94, 761.
(7) For some other examples of titanium (trimethylsilyl)imido halide
complexes see: (a) Alcock, N. W.; Pierce-Butler, M.; Willey, G. R. J.
Chem. Soc., Dalton Trans. 1976, 707. (b) Wollert, R.; Wocadlo, S.;
Dehnicke, K.; Goesmann, H.; Fenske, D. Z. Natursorsch 1992, 47b,
1386. (c) Schlichenmaier, R.; Stra¨hle, J. Z. Anorg. Allg. Chem. 1993,
619, 1526. (d) Alcock, N. W.; Pierce-Bulter, M.; Willey, G. R. Chem.
Commun. 1974, 627. (e) Vasisht, S. K.; Sharma, R.; Goyal, V. Indian
J. Chem. 1985, 24A, 37.
(2) For some examples of complexes bearing But3SiN terminal
groups, see: (a) Holmes, S. M.; Schafer, D. F., II; Wolczanski, P. T.;
Lobkovsky, E. B. J. Am. Chem. Soc. 2001, 123, 10571. (b) Schafer, D.
F.; Wolczanski, P. T. J. Am. Chem. Soc. 1998, 120, 4881. (c) Schaller,
C. P.; Wolczanski, P. T. Inorg. Chem. 1993, 32, 131. (d) de With, J.;
Horton, A. D.; Orpen, A. G. Organometallics 1990, 9, 2207.
(3) For a transition-metal (triarylsilyl)imido example see: (a) Da-
nopoulos, A. A.; Redshaw, C.; Vaniche, A.; Wilkinson, G.; Hussain-
Bates, B.; Hursthouse, M. B. Polyhedron 1993, 12, 1061. For an
interesting main-group example, see: (b) Cui, C.; Ko¨pke, S.; Herbst-
Irmer, R.; Roesky, H. W.; Noltemeyer, M.; Schmidt, H. G.; Wrackmeyer,
B. J. Am. Chem. Soc. 2001, 123, 9091.
(8) Putzer, M. A.; Neumu¨ller, B.; Dehnicke, K. Z. Anorg. Allg. Chem.
1998, 624, 57.
(9) Hanna, T. E.; Keresztes, I.; Lobkovsky, E.; Bernskoetter, W. H.;
Chirik, P. J. Organometallics 2004, 23, 3448.
(10) Gardner, J. D.; Robson, D. A.; Rees, L. H.; Mountford, P. Inorg.
Chem. 2001, 40, 820.
(4) Odom, A. L. Dalton 2005, 225.
10.1021/om050179s CCC: $30.25 © 2005 American Chemical Society
Publication on Web 05/25/2005

(Triphenylsilyl)imido Complexes of Ti and Zr
Organometallics, Vol. 24, No. 13, 2005 3273
amidinatetitanium complexes were reported by Haga-
dorn and Arnold to generate (trimethylsilyl)imido com-
plexes.11 In addition, Woo and co-workers oxidized the
formally titanium(II) porphyrin complex Ti(TTP)(η2-3-
hexyne) with Me3SiN3 to generate Me3SiNdTi(TTP).12
In this paper, we report that (triphenylsilyl)imido
complexes of titanium and zirconium are readily pre-
pared by transimination of tert-butylimido groups with
readily available H2NSiPh3. Included among the new
complexes reported is the simple, useful starting mate-
rial Ph3SiNdTiCl2(pyridine)2.
Results and Discussion
(Triphenylsilyl)amine is commercially available or is
readily prepared in high yield by the action of ammonia
on a benzene solution of ClSiPh3. Several methods for
the generation of (triphenylsilyl)imido complexes of
group 4 were explored. The reaction of H2NSiPh3 with
TiCl4 in the presence of pyridine (py) under conditions
similar to those used to prepare Mountford’s reagent,
Ti(NBut)Cl2(py)3,13 did not afford an isolable terminal
imido complex. However, transimination13b by reaction
of Ti(NBut)Cl2(py)3 with H2NSiPh3 in chlorobenzene (eq
1) provided the dichloride starting material [Ti(NSiPh3)-
Cl2(py)2]2 (1), which precipitates as a yellow crystalline
solid during the reaction in 88% yield.
Figure 1. ORTEP representation of the structure of
[Ti(NSiPh3)Cl2(py)2]2 (1) from X-ray diffraction. The mol-
ecule resides on a crystallographic inversion center.
Table 1. Selected Bond Distances (Å) and Angles
(deg) from the X-ray Diffraction Study on
[Ti(NSiPh3)Cl2(py)2]2 (1)
Ti-N(3)
1.716(7)
2.232(8)
2.443(3)
Ti-N(2)
Ti-Cl(1)
Ti-Cl(2′)
2.219(8)
2.355(3)
2.755(3)
Ti-N(1)
Ti-Cl(2)
Ti-N(3)-Si
171.1(5)
N(3)-Ti-N(1)
Cl(1)-Ti-Cl(2)
Cl(2)-Ti-Cl(2′)
N(3)-Ti-N(1)
96.7(3)
160.7(1)
76.5(1)
95.5(3)
N(2)-Ti-N(1)
N(3)-Ti-Cl(2′)
Cl(1)-Ti-Cl(2′)
167.8(3)
174.7(3)
84.3(1)
stituents. The TidN bond distance is unremarkable at
1.714(8) Å, and the imido is linear, with a TidN-Si
angle of 170.6(5)°. The pyridine rings on opposing
titanium centers across the Ti2Cl2 ring are parallel; the
arrangement and distance between the π-systems of
3.62 Å are suggestive of π-stacking interactions: cf. the
interlayer distance in graphite of 3.35 Å.
While complex 1 is a dimer in the solid state, solution
molecular weight measurements in CH2Cl2 are more
consistent with a monomer formulation in that solvent.
The tert-butylimido analog of 1 has been extensively
used in the synthesis of new imido complexes.14 Con-
sequently, we explored the chloride metathesis chem-
istry and pyridine replacement reactions of 1.
The transimination apparently proceeds to full con-
version with no tert-butylimido complex remaining. A
possible explanation for the greater stability of the
silylimido is that the SiPh3 group may stabilize the
partial negative charge on the nitrogen of the imido,
leading to its preferential formation.
The structure of 1 was determined by X-ray diffrac-
tion. An ORTEP representation of the structure is
shown in Figure 1. In the solid state, the compound is
dimeric, with equatorial chlorides of one imido complex
coordinating trans to the imido group. The bridging
chloride trans to the imido has a quite long Ti-Cl
distance of 2.743(4) Å (Table 1). The Ti-Cl distance to
the bridging chloride cis to the imide is lengthened at
2.444(4) Å relative to the terminal chloride at 2.357(4)
Å. These distances are what would be expected, consid-
ering the known strong trans influence of imido sub-
Addition of 4,4′-di-tert-butyl-2,2′-bipyridine (bpy) to
dimeric 1 results in the loss of one pyridine ligand and
formation of monomeric, pseudo-octahedral Ti(NSiPh3)-
Cl2(bpy)(py) (2) (eq 2).
(14) For some examples of substitution on Mountford’s reagent,
see: (a) McInnes, J. M.; Blake, A. J.; Mountford, P. J. Chem. Soc.,
Dalton Trans. 1998, 3623. (b) Wilson, P. J.; Blake, A. J.; Mountford,
P.; Schro¨der, M. Chem. Commun. 1998, 1007. (c) Carmalt, C. J.;
Whaley, S. R.; Lall, P. S.; Cowley, A. H.; Jones, R. A.; McBurnett, B.
G.; Ekerdt, J. G. J. Chem. Soc., Dalton Trans. 1998, 553. (d) Mu¨ller,
E.; Mu¨ller, J.; Olbrich, F.; Bru¨ser, W.; Knapp, W.; Abeln, D.; Edelmann,
F. T. Eur. J. Inorg. Chem. 1998, 87. (e) Stewart, P. J.; Blake, A. J.;
Mountford, P. Organometallics 1997, 17, 33271. (f) Stewart, P. J.;
Blake, A. J.; Mountford, P. Inorg. Chem. 1997, 36, 3616. (g) Blake, A.
J.; Collier, P. E.; Gade, L. H.; McPartlin, M.; Mountford, P.; Schubart,
M.; Scowen, I. J. Chem. Commun. 1997, 1555. (h) Collier, P. E.; Blake,
A. J.; Mountford, P. J. Chem. Soc., Dalton Trans. 1997, 2911. (i) Dunn,
S. C.; Mountford, P.; Robson, D. A. J. Chem. Soc., Dalton Trans. 1997,
293.
(11) (a) Hagadorn, J. R.; Arnold, J. Organometallics 1998, 17, 1355.
(b) Hagadorn, J. R.; Arnold, J. J. Am. Chem. Soc. 1996, 118, 893.
(12) Gray, S. D.; Thorman, J. L.; Berreau, L. M.; Woo, L. K. Inorg.
Chem. 1997, 36, 278.
(13) For a review see: (a) Mountford, P. Chem. Commun. 1997,
2127. See also: (b) Dunn, S. C.; Batsanov, A. S.; Mountford, P. Chem.
Commun. 1994, 2007. (c) Blake, A. J.; Collier, P. E.; Dunn, S. C.; Li,
W.-S.; Mountford, P.; Shishkin, O. V. J. Chem. Soc., Dalton Trans.
1997, 1549.

3274 Organometallics, Vol. 24, No. 13, 2005
Li et al.
A few metathesis reactions with the dichloride start-
ing material 1 were explored (Scheme 1). Three pyrrolyl
ligands are shown in Scheme 1. Reaction of 1 with 2
equiv of Li(dap), where dap15 is R-((dimethylamino)-
methyl)pyrrolyl, generates the five-coordinate complex
Ti(NSiPh3)(dap)2 (3). Reaction with 1 equiv of Li(bap),
where bap is R,R′-bis((dimethylamino)methyl)pyrrolyl,
results in the formation of Ti(NSiPh3)Cl(bap) (4). Simi-
larly, reaction with 1 equiv of Li(pap), where pap is R,R′-
bis(piperidin-1-ylmethyl)pyrrolyl, affords Ti(NSiPh3)-
Cl(pap) (5).
The structure of Ti(NSiPh3)(Cl)(pap) (5) was deter-
mined by X-ray diffraction (Figure 2, Table 2). The
complex is best described as square pyramidal with the
imido nitrogen occupying the axial site. The pap ligand
is tridentate in this case, which is not always the case
with the 2,5-disubstituted pyrrolyl ligands pap and
bap.16
Figure 2. ORTEP representation of the structure of
Ti(NSiPh3)(Cl)(pap) (5) from X-ray diffraction.
Scheme 1. Metathesis Reactions on 1 with
Monoanionic Ligands
As shown in Scheme 1, reaction of 1 with neophyl
(Nph) magnesium chloride provides the dimeric complex
[Ti(µ-NSiPh3)(Nph)2]2 (6). Attempts to convert dimeric
6 into a monomeric, terminal imido complex by addition
of bpy were unsuccessful. Addition of methylalumoxane
to either 1 or 6 did not provide a catalyst capable of
polymerizing 1-hexene.17
The solid-state structure of [Ti(µ-NSiPh3)(Nph)2]2 (6)
was also determined by X-ray diffraction (Figure 3,
Table 3). As shown, the complex is a dimer that resides
on a crystallographically imposed inversion center. The
imido group bridges are chemically identical, with
Ti-N(imido) distances that are identical within error,
1.917(4) and 1.923(4) Å, which as would be expected is
substantially longer than the Ti-N distances of ∼1.70
Å found for the terminal (triphenylsilyl)imido com-
plexes. Each pseudo-tetrahedral titanium center also
bears two neophyl groups with Ti-C distances of
2.064(4) and 2.100(5) Å.
Table 2. Selected Bond Distances (Å) and Angles
(deg) from the X-ray Diffraction Study on
Ti(NSiPh3)(Cl)(pap) (5)
Metathesis on [Ti(NSiPh3)Cl2(py)2]2 (1) with Li2dpma,
where dpma18 is N,N-di(pyrrolyl-R-methyl)-N-methyl-
amine, was also investigated (Scheme 2). Addition of
Li2dpma to 1/2 equiv of [Ti(NSiPh3)Cl2(py)2]2 (1) results
Ti-N(2)
Ti-N(11)
Ti-Cl
1.698 (6)
2.248(6)
2.333(2)
Ti-N(1)
Ti-N(12)
1.995(6)
2.274(6)
(15) (a) Cao, C.; Li, Y.; Shi, Y.; Odom, A. L. Chem. Commun. 2004,
2002. (b) Cao, C.; Shi, Y.; Odom, A. L. Org. Lett. 2002, 4, 2853.
(16) For example, the structure of Ti(NMe2)3(bap) has an η2-bap
structure in the solid state. In solution, the bap ligand is symmetrical,
signifying fast exchange on the NMR time scale. Banerjee, S.; Shi, Y.;
Cao, C.; Odom, A. L. J. Organomet. Chem., in press.
Ti-N(2)-Si
156.5(4)
106.4(2)
73.1(2)
N(2)-Ti-N(1)
N(1)-Ti-N(11)
N(11)-Ti-N(12)
Cl-Ti-N(12)
106.6(3)
73.7(2)
139.7(2)
97.5(2)
N(2)-Ti-N(11)
N(1)-Ti-N(12)
N(2)-Ti-Cl
145.1(2)
(17) Adams, N.; Arts, H. J.; Bolton, P. D.; Cowell, D.; Dubberley, S.
R.; Friederichs, N.; Grant, C. M.; Kranenbrug, M.; Sealey, A. J.; Wang,
B.; Wilson, P. J.; Cowley, A. R.; Mountford, P.; Schroder, M. Chem.
Commun. 2004, 434.
(18) For other dpma reactivity see: (a) Li, Y.; Turnas, A.; Ciszewski,
J. T.; Odom A. L. Inorg. Chem. 2002, 41, 6298. (b) Katayev, E.; Li, Y.;
Odom, A. L. Chem. Commun. 2002, 838. (c) Harris, S. A.; Ciszewski,
J. T.; Odom, A. L. Inorg. Chem. 2001, 40, 1987. (d) Cao, C.; Shi, Y.;
Odom, A. L. J. Am. Chem. Soc. 2003, 125, 2880. (e) Cao, C.; Ciszewski,
J. T.; Odom, A. L. Organometallics 2001, 20, 5011. (f) Li, Y.; Shi, Y.;
Odom, A. L. J. Am. Chem. Soc. 2004, 126, 1794.
in the formation of Ti(NSiPh3)(dpma)(py)2 (7) in 36%
yield. It is currently unknown whether 7 has a cis or
trans geometry with respect to the pyridine ligands;
both geometries have precedents in other Ti(imido)-
(dpma)L2 complexes.18 Treatment of 7 with bpy provided
Ti(NSiPh3)(dpma)(bpy) (8) in 76% yield. A shorter,
alternative procedure to obtain 8 (Scheme 2) involves
the action of H2NSiPh3 on a solution of Ti(NMe2)2(dpma)

(Triphenylsilyl)imido Complexes of Ti and Zr
Organometallics, Vol. 24, No. 13, 2005 3275
Scheme 3. Synthetic Route to
Zr(NSiPh3)(dpma)(bpy) (10)
(bpy)(dpma) (9) was synthesized by addition of tert-
butylamine to a solution of Zr(dpma)(py)(NMe2)218a and
bpy in 43% yield. Treatment of 9 with H2NSiPh3
afforded silylimido Zr(NSiPh3)(dpma)(bpy) (10) in 34%
isolated yield (Scheme 3). As with the synthesis of
[Ti(NSiPh3)Cl2(py)2]2 (1) (vide supra), attempts to cir-
cumvent the transimination procedure and avoid the
formation of tert-butylimido 9 were unsuccessful. In
other words, addition of H2NSiPh3 to a solution of
Zr(dpma)(py)(NMe2)2 and bpy did not provide observ-
able quantities of 10.
Figure 3. ORTEP representation of the structure of
[Ti(µ-NSiPh3)(Nph)2]2 (6) from X-ray diffraction. The mol-
ecule resides on a crystallographic inversion center.
Table 3. Selected Bond Distances (Å) and Angles
(deg) from the X-ray Diffraction Study on
[Ti(µ-NSiPh3)(Nph)2]2 (6)
Ti-N
Ti-C(3)
1.923(4)
2.064(4)
Ti-N′
Ti-C(2)
1.917(4)
2.100(5)
Ti-N-Si
C(2)-Ti-C(3)
N-Ti-C(3)
133.6(2)
110.1(2)
119.3(2)
Ti-N-Ti′
N-Ti-C(2)
93.4(2)
115.0(2)
In a very unusual reaction, addition of an excess of
sodium 2,6-dimethylphenoxide to 10 results in the loss
of the imido ligand entirely to form the triaryloxide
zirconate complex [(bpy)Na][Zr(OAr)3(dpma)] (11) (eq 3).
Scheme 2. Two Routes to Ti(NSiPh3)(dpma)(bpy)
(8)
The complex was structurally characterized (Figure 4,
Table 4), and the sodium is bound to the bpy ligand and,
in a bis-η5 fashion, to the two pyrrolyl substituents of
and bpy, which afforded 8 in 51% yield. Complex 8 was
also structurally characterized (see the Supporting
Information for details).
The addition of various primary amines to alkynes,
hydroamination, is catalyzed by Ti(NMe2)2(dpma).18 In
these reactions, titanium imido complexes are likely
intermediates. Considering the formation and isola-
tion of an imido complex on addition of H2NSiPh3 to
Ti(NMe2)2(dpma) shown above, we were somewhat
surprised to find that the reaction of 1-hexyne and
H2NSiPh3 in the presence of this titanium complex did
not afford the expected hydroamination product. It is
currently unknown if it is steric and/or electronic factors
that result in this lack of reactivity.
Access to zirconium (triphenylsilyl)imido complexes
was accomplished through transimination on a tert-
butylimido complex as well. The new imido Zr(NBut)-
Figure 4. ORTEP representation of the structure of
[(bpy)Na][Zr(OAr)3(dpma)] (11) from X-ray diffraction.

3276 Organometallics, Vol. 24, No. 13, 2005
Li et al.
described.18a Ti(NBut)Cl2(py)3,13 Hbap,19 Hdap,19 and Hpap19
were prepared using the literature procedures. Ph3SiCl was
purchased from Aldrich Chemical Co. and was used as
received.
Table 4. Selected Bond Distances (Å) and Angles
(deg) from the X-ray Diffraction Study on
[(bpy)Na][Zr(OAr)3(dpma)] (11)
Zr-O(6)
Zr-O(8)
Zr-N(2)
Na-N(4)
1.945(9)
Zr-O(7)
Zr-N(1)
Zr-N(3)
Na-N(5)
1.983(11)
2.291(14)
2.468(3)
General Considerations for X-ray Diffraction. Crystals
grown from concentrated solutions at -35 °C were moved
quickly from a scintillation vial to a microscope slide containing
Paratone N. Samples were selected and mounted on a glass
fiber in wax and Paratone. The data collections were carried
out at a sample temperature of 173 K on a Bruker AXS plat-
form three-circle goniometer with a CCD detector. The data
were processed and reduced utilizing the program SAINT-
PLUS supplied by Bruker AXS. The structures were solved
by direct methods (SHELXTL v5.1, Bruker AXS) in conjunction
with standard difference Fourier techniques. Structural pa-
rameters for 1, 5, 6, 8, and 11 are given in Table 5.
Synthesis of H2NSiPh3. A solution of 16 g of Ph3SiCl (54.3
mmol) in 250 mL of anhydrous benzene was placed in a 500
mL round-bottom flask equipped with a mechanical stirrer, a
water-cooled condenser, and a gas inlet tube. The system was
kept under dry nitrogen through a gas adapter fixed to the
top of the condenser. The gas inlet tube extended ∼1 cm below
the surface of the stirred reaction mixture. The gas inlet tube
was connected to a tank of ammonia through an empty trap
(in case of accidental backup of solution) and to an oil-filled
bubbler through a glass T-tube. An external ice-water bath
was used to keep the temperature of the reaction mixture
below 30 °C. A slow stream of ammonia was passed into the
reaction flask, and a precipitate of ammonium chloride ap-
peared during addition. The gas flow was continued for 6 h.
Then, the reaction mixture was refluxed for 3 h to remove
excess ammonia. The reaction mixture was cooled to room
temperature and taken into a glovebox. The precipitate was
removed by filtration through a fritted funnel. The solid
residue was washed with small portions equaling ∼100 mL of
C6H6, and the filtrates were combined. The volatiles of the
mixture were removed in vacuo to yield a white solid. The solid
was recrystallized from benzene/pentane to yield (triphenyl-
silyl)amine as a white solid. Yield: 13.9 g (93%). 1H NMR
(300 MHz, CDCl3): δ 7.79 (6H, m, 2,6-Si(C6H5)3), 7.65 (3H, m,
4-Si(C6H5)3), 7.53 (6H, m, 3,5-Si(C6H5)3), 1.41 (2H, s, H2NSi)).
13C NMR (CDCl3): δ 135.2 (2,6-C6H5), 135.1 (3,5-C6H5), 129.6
(1-C6H5), 127.8 (4-C6H5).
2.005(11)
2.211(13)
2.397(17)
2.374(17)
O(6)-Zr-O(7)
O(7)-Zr-N(8)
O(7)-Zr-N(2)
N(2)-Zr-N(1)
99.7(4)
95.5(4)
91.1(5)
78.9(5)
O(6)-Zr-O(8)
O(6)-Zr-N(2)
O(8)-Zr-N(2)
N(1)-Zr-N(3)
103.0(4)
97.5(5)
157.0(4)
74.4(4)
the dpma. The zirconium is pseudo-octahedral, with the
aryloxide ligands facially occupying three sites. The
reaction was run at 110 °C for 5 days in THF. Attempts
to run the reaction under milder conditions afforded the
same product at slower rates without observed inter-
mediates. The binding of the pyrrolyl ligands to the
sodium does not effect the Zr-N(pyrrolyl) bonding, as
judged by the metrical parameters from X-ray diffrac-
tion. The Zr-N(pyrrolyl) distances in 10 average
2.25(1) Å, which is very similar to the distances in
Zr(NMe2)2(NHMe2)(dpma) of 2.232(4) Å.18a The average
Na-centroid distance in the pyrrole ring is 2.53 Å, with
a centroid-Na-centroid angle of 107°.
Concluding Remarks
(Triphenylsilyl)imido complexes of titanium and zir-
conium are readily available from transimination of the
tert-butylimido derivatives. For example, the useful
starting material [Ti(NSiPh3)Cl2(py)2]2 (1) is prepared
in 88% yield from Mountford’s reagent, Ti(NSiPh3)-
Cl2(py)3, and H2NSiPh3. Halide replacement on 1 with
Grignard and lithium reagents often occurs smoothly
to afford new imido complexes. As a result, this chem-
istry offers a new inlet into (triarylsilyl)imido complexes
that will likely provide some variability in steric and
electronic control at the imido substituent through the
use of different substitution patterns on readily pre-
pared Ar3SiNH2 starting materials.
Synthesis of [Ti(NSiPh3)Cl2py2]2 (1). To an orange solu-
tion of Ti(NBut)Cl2py3 (1.770 g, 4.15 mmol) in 20 mL of
chlorobenzene was added H2NSiPh3 (1.142 g, 4.15 mmol) in 5
mL of chlorobenzene in a threaded thick-walled reaction vessel.
The vessel was capped with a Teflon stopper and removed from
the drybox. The reaction mixture was heated in a 60 °C oil
bath for 2 h. During heating, a yellow solid precipitated from
solution. The solid was collected by filtration and dried under
Experimental Section
General Considerations. All manipulations of air-sensi-
tive compounds were carried out in an MBraun drybox under
a purified nitrogen atmosphere. Anhydrous ether was pur-
chased from Columbus Chemical Industries Inc. and freshly
distilled from purple sodium benzophenone ketyl. Toluene was
purchased from Spectrum Chemical Mfg. Corp. and purified
by refluxing over molten sodium under nitrogen for at least 2
days. Pentane (Spectrum Chemical Mfg. Corp.), tetrahydro-
furan (JADE Scientific), and benzene (EM Science) were
distilled from purple sodium benzophenone ketyl. Dichlo-
romethane (EM Science) and acetonitrile (Spectrum Chemical)
were distilled from calcium hydride. Deuterated solvents were
dried over purple sodium benzophenone ketyl (C6D6) or
phosphoric anhydride (CDCl3) and distilled under nitrogen.
1H and 13C NMR spectra were recorded on Inova-300 or VXR-
500 spectrometers. 1H and 13C assignments were confirmed
1
reduced pressure. Yield: 2.012 g (88%). H NMR (300 MHz,
CDCl3): δ 9.02 (4 H, m, 2-C5H5N), 7.69 (4 H, m, 3-C5H5N),
7.36-7.22 (17 H, m, Si(C6H5)3 and 4-C5H5N). 13C NMR (CDCl3):
δ 151.3 (4-C5H5N), 138.8 (3-C5H5N), 135.4 (4-C5H5N), 129.3
(1-C6H5), 127.7 (2-C6H5 and 3-C6H5), 124.3 (4-C6H5).
Synthesis of Ti(NSiPh3)Cl2(But-bpy)(py) (2). To a yellow
solution of Ti(NSiPh3)Cl2py2 (1; 1.116 g, 2.03 mmol) in 10 mL
of CH2Cl2 was added But-bpy (545 mg, 2.03 mmol) in 5 mL of
CH2Cl2. After the mixture was stirred at room temperature
for 16 h, volatiles of the reaction mixture were removed in
vacuo to yield a yellow solid. The solid was recrystallized from
1
CH2Cl2. Yield: 1.107 g (74%). H NMR (300 MHz, CDCl3): δ
1
when necessary with the use of two-dimensional H-1H and
9.63 (2H, d, 6,6′-bpy), 7.88 (2H, s, 3,3′-bpy), 7.53 (2H, d, 5,5′-
bpy), 7.41 (6H, m, 2,6-Si(C6H5)3), 7.25 (3H, m, 4-Si(C6H5)3), 7.14
(6H, m, 3,5-Si(C6H5)3), 1.42 (18H, s, But). 13C NMR (CDCl3):
δ 164.6 (2,2′-bpy), 152.9 (6,6′-bpy), 152.2 (4,4′-bpy), 136.8
(1-C6H5), 134.0 (3,3′-bpy), 128.5 (5,5′-bpy), 127.1 (2-C6H5), 122.8
(3-C6H5), 117.4 (4-C6H5), 35.4 (C(CH3)3-bpy), 30.3 (C(CH3)3-
13C-1H correlation NMR experiments. All spectra were ref-
erenced internally to residual protio solvent (1H) or solvent
(13C) resonances. Chemical shifts are quoted in ppm and
coupling constants in Hz, and common coupling constants are
not provided. The gaseous ammonia was 99.99% anhydrous
NH3 purchased from AGA Gas, Inc. H2dpma, Zr(dpma)(py)-
(NMe2)2, and Ti(NMe2)2(dpma) were prepared as previously
(19) Kim, H.; Elsenbaumer, R. L. Tetrahedron Lett. 1998, 39, 1087.

(Triphenylsilyl)imido Complexes of Ti and Zr
Organometallics, Vol. 24, No. 13, 2005 3277
Table 5. Structural Parameters for [Ti(NSiPh3)(py)2Cl2]2 (1‚CH2Cl2), Ti(NSiPh3)(pap)Cl (5‚C7H8),
[Ti(Nph)2(µ-NSiPh3)]2(6), Ti(NSiPh3)(bpy)(dpma) (8‚CH2Cl2), and [Na(bpy)][Zr(dpma)(OAr)3] (11‚C7H8)
1
5
6
8
11
formula
formula wt
space group
a (Å)
C
29H27Cl4N3SiTi2
C41H49ClN4SiTi
709.28
C38H41NSiTi
587.71
C48H54Cl2N6SiTi
861.86
C60H72N5NaO3Zr
1025.44
P1h
645.33
P21/c
P21/c
C2/c
P21/c
9.100(2)
18.062(5)
18.337(4)
11.880(3)
19.005(4)
17.779(4)
25.633(4)
11.2928(17)
22.587(4)
12.3148(18)
17.191(3)
22.176(4)
12.468(3)
15.019(3)
13.703(3)
84.293(7)
86.841(5)
75.727(5)
3506.0(19)
2
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
102.342(5)
92.182(4)
99.0.119(3)
98.280(4)
2944.4(12)
4
4011.2(16)
4
0.342
1.174
33 445
5774 (0.081)
0.010(2)
0.0965
0.3098
6455.5(17)
8
4645.6(12)
4
Z
µ (mm-1
)
0.719
0.329
0.364
0.201
Dcalcd (g cm-3
)
1.433
1.209
1.232
0.971
total no. of rflns
no. of unique rflns (Rint
extinction
1322
26 453
16 689
29 851
)
4212 (0.295)
0.0004(5)
0.0756
0.1381
4666 (0.1518)
0.00019(16)
0.0615
6401 (0.1256)
0.00126(10)
0.0481
10 139 (0.351)
none
R(Fo) (I > 2σ)
0.1396
0.3590
Rw(Fo2) (I > 2σ)
0.1572
0.0668
bpy). Anal. Found (calcd) for C36H39N3Cl2SiTi: C, 64.98 (65.38);
H, 6.15 (5.90); N, 6.23 (6.36).
was recrystallized from CH2Cl2/pentane at -35 °C to pro-
1
vide the product as yellow crystals. Yield: 177 mg (76%). H
NMR (300 MHz, CDCl3): δ 7.90 (2 H, s, 3,3′-[But-bpy]), 7.69 (2
H, s, 5-C4H3N), 7.41 (8 H, m, 2-C6H5 and 5,5′-[But-bpy]), 7.35
(2 H, s, 6,6′-[But-bpy]), 7.20 (4 H, m, 4-C6H5), 7.09 (6 H, m,
3-C6H5), 6.13 (2 H, s, 4-C4H3N), 5.93 (2 H, s, 3-C4H3N), 3.75
(2 H, d, 2J ) 13.7 Hz, C4H3NCH2N), 3.07 (2 H, d, 2J )
13.7 Hz, C4H3NCH2N), 1.45 (3 H, s, C4H3NCH2N(CH3)), 1.42
(18 H, s, C(CH3)3-[But-bpy]). 13C NMR (CDCl3): δ 164.4
(2,2′-[But-bpy]), 152.6 (4.4′-[But-bpy]), 151.5 (6.6′-[But-bpy]),
139.1 (2-C4H3N), 136.9 (1-C6H5), 136.1 (2-C6H5), 132.0 (4-C6H5),
128.1 (5.5′-[But-bpy]), 127.0 (3-C6H5), 123.7 (5-C4H3N),
116.9 (3,3′-[But-bpy]), 107.1 (4-C4H3N), 102.6 (3-C4H3N), 58.0
(C4H3NCH2N), 44.2 (C(CH3)3-[But-bpy]), 35.4 (C4H3NCH2N-
(CH3)), 30.3 (C(CH3)3-[But-bpy]). Anal. Found (calcd) for
C47H52N6SiTi: C, 72.66 (72.64); H, 6.87 (6.70); N, 10.53 (10.82).
Synthesis of [Ti(NSiPh3)(neophyl)]2 (6). To a near-frozen
solution of Ti(NSiPh3)Cl2py2 (1; 550 mg, 1.00 mmol) in 10 mL
of Et2O was added a solution of ClMgCH2C(Me)2Ph (4 mL, 2.00
mmol, 0.5 M solution in Et2O) dropwise. After it was stirred
at room temperature for 16 h, the resulting orange solution
was filtered to remove a white solid. Volatiles were removed
from the solution in vacuo, yielding the product, which was
recrystallized from CH2Cl2/pentane. Yield: 350 mg (59%). 1H
NMR (300 MHz, CDCl3): δ 7.78 (6H, d, 2,6-Si(C6H5)3), 7.45 (3H,
m, 4-Si(C6H5)3), 7.36 (6H, m, 3,5-Si(C6H5)3), 7.12 (4H, m, 3,5-
C(C6H5)), 7.07 (2H, m, 4-C(C6H5)), 6.87 (4H, d, 2,6-C(C6H5)),
2.13 (4H, s, CH2C(Me)2Ph), 0.92 (12H, s, CH2C(Me)2Ph). 13C
NMR (CDCl3): δ 136.8 (2-C6H5), 135.5 (1-C6H5), 130.2 (4-C6H5),
128.2 (6-C6H5), 125.5 (5-C6H5), 111.4 (CH2C(Me)2Ph), 32.6
(CH2C(Me)2Ph), 31.6 (CH2C(Me)2Ph). Anal. Found (calcd) for
C76H82N2Si2Ti2: C, 77.64 (76.82); H, 6.98 (6.97); N, 2.38 (2.41).
Synthesis of Ti(NSiPh3)(dpma)(py)2 (7). To a near-frozen
solution of Ti(NSiPh3)Cl2py2 (1; 932 mg, 1.69 mmol) in 20 mL
of toluene was added Li2dpma (340 mg, 1.69 mmol) in 10 mL
of toluene dropwise. After it was stirred at room temperature
for 48 h, the resulting dark yellow solution was filtered to
remove a white solid. Volatiles were removed from the reaction
in vacuo, yielding the solid crude product, which was recrys-
tallized from toluene at -35 °C to provide a yellow solid.
Yield: 405 mg (36%). 1H NMR (300 MHz, CDCl3): δ 8.10 (2 H,
d, 2-C5H5N), 7.87 (2 H, d, 4-C5H5N), 7.73 (2 H, app s, 3-C4H3N),
7.65 (2 H, m, 3-C5H5N), 7.31-7.10 (19 H, m, Si(C6H5)3,
2-C5H5N, and 3-C5H5N), 6.29 (2 H, m 4-C4H3N), 5.99 (2 H,
m, 5-C4H3N), 3.41 (4 H, s, C4H3NCH2N(CH3)), 1.69 (3 H, s,
C4H3NCH2N(CH3)). 13C NMR (CDCl3): δ 151.3 (2-C5H5N),
150.6 (2-C5H5N), 139.7 (3-C5H5N), 138.3 (3-C5H5N), 137.6
(2-C4H3N), 135.1 (4-C5H5N), 130.1 (1-C6H5), 128.3 (2-C6H5),
127.1 (5-C4H3N), 124.8 (3-C6H5), 59.6 (C4H3NCH2N(CH3)), 45.1
(C4H3NCH2N(CH3)). Anal. Found (calcd) for C39H38N6SiTi: C,
69.76 (70.28); H, 5.71 (5.71); N, 12.38 (12.61).
Synthesis of Ti(NSiPh3)(dap)2 (3). To a near-frozen
solution of Ti(NSiPh3)Cl2py2 (1; 410 mg, 0.75 mmol) in 10 mL
of toluene was added Lidap (194 mg, 1.49 mmol) in toluene
(10 mL) dropwise. After it was stirred at room temperature
for 24 h, the resulting dark yellow solution was filtered to
remove a white solid. Volatiles were removed from the solution
under reduced pressure to yield the crude product, which was
1
recrystallized from CH2Cl2/pentane. Yield: 51 mg (12%). H
NMR (300 MHz, CDCl3): δ 7.52-7.26 (15 H, m, Si(C6H5)3), 7.08
(2 H, s, 5-C4H3N), 6.36 (2 H, m, 4-C4H3N), 6.18 (2 H, s,
3-C4H3N), 4.58 (2 H, d, 2J ) 13.3 Hz, C4H3NCH2N(CH3)2),
3.62 (2 H, d, 2J
) 13.3 Hz, C4H3NCH2N(CH3)2), 2.87
(6 H, s, C4H3NCH2N(CH3)2), 2.55 (6 H, s, C4H3NCH2N-
(CH3)2). 13C NMR (CDCl3): δ 136.7 (2-C4H3N), 135.4 (1-C6H5),
129.2 (4-C6H5), 127.8 (2-C6H5), 125.9 (5-C4H3N), 108.6 (4-
C4H3N), 105.5 (3-C4H3N), 61.87 (C4H3NCH2N (CH3)2), 50.0
(C4H3NCH2N(CH3)2), 45.8 (C4H3NCH2N(CH3)2). Anal. Found
(calcd) for C32H37N5SiTi: C, 67.52 (67.69); H, 6.79 (6.52); N,
12.07 (12.34).
Synthesis of Ti(NSiPh3)(bap)(Cl) (4). To a near-frozen
solution of Ti(NSiPh3)(Cl)2(py)2 (1; 782 mg, 1.42 mmol) in 10
mL of toluene was added Libap (266 mg, 1.42 mmol) in toluene
(10 mL) dropwise. After it was stirred at room temperature
for 24 h, the resulting pink solution was filtered to remove a
white solid. Volatiles were removed in vacuo to yield a pink
solid. The solid was recrystallized from CH2Cl2/pentane at -35
°C. Yield: 279 mg (37%). 1H NMR (300 MHz, CDCl3): δ 7.63-
7.59 (6 H, m, Si(C6H5)3), 7.35-7.27 (9 H, m, Si(C6H5)3), 5.96
(2 H, s, C4H2N), 4.23 (2 H, d, 2J ) 13.2 Hz, C4H2NCH2N(CH3)2),
3.50 (2 H, d, 2J ) 13.2 Hz, C4H2NCH2N(CH3)2), 2.75 (6 H,
s, C4H2NCH2N(CH3)2), 2.46 (6 H, s, C4H2NCH2N(CH3)2).
13C NMR (CDCl3): δ 137.3 (2-C4H2N), 135.2 (1-C6H5), 134.4
(4-C6H5), 129.0 (2-C6H5), 127.6 (3-C6H5), 103.5 (3-C4H2N),
65.2 (C4H2NCH2N (CH3)2), 50.0 (C4H2NCH2N(CH3)2), 48.4
Synthesis of Ti(NSiPh3)(dpma)(bpy) (8). Method A. To
a mixture of Ti(NMe2)2(dpma) (200 mg, 0.62 mmol) and But-
bpy (166 mg, 0.62 mmol) in chlorobenzene (5 mL) was added
H2NSiPh3 (170 mg, 0.62 mmol) in chlorobenzene (5 mL). The
Schlenk flask was taken out of the drybox and heated under
N2 at 60 °C. After the mixture was heated for 16 h, the volatiles
were removed in vacuo, resulting in a yellow solid, which was
washed with pentane. Yield: 245 mg (51%).
Method B. To a yellow solution of Ti(NSiPh3)(dpma)(py)2
(7; 199 mg, 0.3 mmol) in 5 mL of toluene was added 4,4′-di-
tert-butyl-2,2′-dipyridyl (80 mg, 0.3 mmol) in toluene (5 mL).
The reaction mixture was stirred for 16 h, after which time
volatiles were removed in vacuo. The resulting yellow solid

3278 Organometallics, Vol. 24, No. 13, 2005
Li et al.
2
2
(C4H2NCH2N(CH3)2). Anal. Found (calcd) for C28H33N4ClSiTi:
C, 62.15 (62.65); H, 6.26 (6.15); N, 10.47 (10.44).
H, d, J ) 13.7 Hz, C4H3NCH2N), 3.18 (2 H, d, J ) 13.7 Hz,
C4H3NCH2N), 1.40 (3 H, s, C4H3NCH2N(CH3)), 1.39 (18 H, s,
C(CH3)3-[But-bpy]). 13C NMR (CDCl3): δ 165.4 (2,2′-[But-bpy]),
153.1 (4,4′-[But-bpy]), 151.4 (6,6′-[But-bpy]), 149.1 (2-C4H3N),
142.1 (1-C6H5), 137.1 (2-C6H5), 135.1 (4-C6H5), 130.7 (5.5′-[But-
bpy]), 127.4 (3-C6H5), 126.7 (5-C4H3N), 117.8 (3,3′-[But-bpy]),
108.1 (4-C4H3N), 105.2 (3-C4H3N), 57.6 (C4H3NCH2N), 43.9
(C(CH3)3-[But-bpy]), 35.6 (C4H3NCH2N(CH3)), 30.6 (C(CH3)3-
[But-bpy]). Anal. Found (calcd) for C47H52N6SiZr: C, 68.35
(68.80); H, 6.41 (6.34); N, 10.20 (10.25).
Synthesis of Ti(NSiPh3)(pap)(Cl) (5). To a yellow solution
of Ti(NSiPh3)(Cl)2(py)2 (1; 616 mg, 1.12 mmol) in toluene (10
mL) cooled to nearly freezing was added Lipap (299 mg, 1.12
mmol) in 10 mL of toluene dropwise. After it was stirred at
room temperature for 24 h, the resulting pink solution was
filtered to remove a white solid. Volatiles were removed in
vacuo. The solid was recrystallized from CH2Cl2/pentane at
-35 °C to provide pink crystals. Yield: 254 mg (37%). 1H NMR
(300 MHz, C6D6): δ 7.66 (3 H, m, Si(C6H5)3), 7.27-7.16 (12 H,
m, Si(C6H5)3), 5.13 (2 H, s, C4H2N), 3.30 (4 H, s, C4H2NCH2N-
(C5H10)), 2.24 (8 H, s, 2-N(C5H10)), 1.48-1.41 (8 H, m,
3-N(C5H10)), 1.31-1.22 (4 H, m, 4-N(C5H10)). 13C NMR (C6D6):
δ 136.9 (2-C4H2N), 135.8 (1-C6H5), 135.2 (4-C6H5), 129.0 (2-
C6H5), 127.4 (3-C6H5), 106.9 (2-C4H2N), 104.1 (3-C4H2N), 54.3
(C4H2NCH2N(C5H10)), 26.1 (2-N(C5H10)), 24.6 (3-N(C5H10)),
23.1(4-N(C5H10)). Anal. Found (calcd) for C34H41N4ClSiTi: C,
66.21 (66.20); H, 7.04 (6.65); N, 9.40 (9.08).
Synthesis of [(bpy)Na][Zr[O-(2,6-MeC6H3)]3(dpma)] (11).
To a yellow solution of Zr(NSiPh3)(dpma)(bpy) (10; 2.93 g, 3.57
mmol) in 20 mL of THF was added NaO(2,6-Me2C6H3) (1.55
g, 10.72 mmol) in THF (10 mL). The reaction vessel was
removed from the box in a sealed vessel and heated to 110 °C
in an oil bath. After the mixture was heated to 110 °C for 5
days, the flask was cooled and brought inside the box. Volatiles
were removed in vacuo to yield a light yellow solid. The solid
was recrystallized from toluene/pentane at -35 °C. Yield: 1.62
Synthesis of Zr(NBut)(dpma)(bpy) (9). To a solution of
Zr(dpma)(py)(NMe2)2 (1.39 g, 3.12 mmol) and 4,4′-di-tert-butyl-
2,2′-dipyridyl (836 mg, 3.11 mmol) in toluene (10 mL) cooled
to nearly freezing was added H2NBut (228 mg, 3.12 mmol) in
toluene (5 mL) dropwise. After the mixture was stirred at room
temperature overnight, an orange solid precipitated from the
solution. The solid was collected by filtration and dried in
vacuo. Yield: 819 mg (43%). 1H NMR (300 MHz, CDCl3): δ
8.10 (2 H, d, 3,3′-[But-bpy]), 7.98 (2 H, s, 6,6′-[But-bpy]), 7.68
(2 H, m, 5-C4H3N), 7.47 (2 H, m, 5,5′-[But-bpy]), 6.27 (2 H, m,
g (49%). H NMR (300 MHz, C6D6): δ 8.18 (2H, s, 6,6′-[But-
1
bpy]), 8.07 (6 H, m, 3-(2,6-MeC6H3)), 7.50 (3,3′-[But-bpy]), 7.40
(2 H, s, 5-C4H3N), 6.97 (3 H, m, 4-(2,6-MeC6H3)), 6.72 (2 H, s,
5,5′-[But-bpy]), 5.87 (2 H, s, 4-C4H3N), 5.68 (2 H, s, 3-C4H3N),
2
2
3.86 (2 H, d, J ) 14.6 Hz, C4H3NCH2N), 3.21 (2 H, d, J )
14.4 Hz,C4H3NCH2N), 2.37 (18 H, s, Me-(2,6-MeC6H3)), 2.06
(3 H, s, C4H3NCH2N(CH3)), 0.96 (18 H, s, C(CH3)3-[But-bpy]).
13C NMR (C6D6): δ 161.8 (2,2′-[But-bpy]), 161.3 (ipso-2,6-
MeC6H3), 155.2 (4,4′-[But-bpy]), 150.2 (6,6′-[But-bpy]), 143.9
(2-C4H3N), 135.9 (5,5′-[But-bpy]), 127.1 (2-(2,6-MeC6H3)), 125.5
(5-C4H3N), 121.1 (3-(2,6-MeC6H3)), 118.0 (3.3′-[But-bpy]), 117.1
(4-(2,6-MeC6H3)), 107.1 (4-C4H3N), 101.4 (3-C4H3N), 67.8
(C4H3NCH2N), 62.1 (C(CH3)3-[But-bpy]), 34.5 (C4H3NCH2N-
(CH3)), 30.0 (C(CH3)3-[But-bpy]), 18.2 (Me-(2,6-MeC6H3)). Anal.
Found (calcd) for C53H64N5O3Zr: C, 68.93 (68.24); H, 6.75
(6.87); N, 7.11 (7.51).
2
4-C4H3N), 6.04 (2 H, s, 3-C4H3N), 3.85 (2 H, d, J ) 13.8 Hz,
2
C4H3NCH2N), 3.20 (2 H, d, J ) 13.6 Hz, C4H3NCH2N), 1.64
(3 H, s, C4H3NCH2N(CH3)), 1.47 (18 H, s, C(CH3)3-[But-bpy]),
1.00 (9 H, s, NC(CH3)3). 13C NMR (CDCl3): δ 164.4 (2,2′-
[But-bpy]), 153.0 (4,4′-[But-bpy]), 151.6 (6,6′-[But-bpy]),
136.8 (2-C4H3N), 130.7 (5,5′-[But-bpy]), 123.1 (5-C4H3N),
117.5 (3,3′-[But-bpy]), 107.3 (4-C4H3N), 104.3 (3-C4H3N), 57.6
(C4H3NCH2N), 43.5 (C(CH3)3-[But-bpy]), 35.4 (C4H3NCH2N-
(CH3)), 34.2 (TiNC(CH3)3), 30.6 (TiNC(CH3)3), 30.3 (C(CH3)3-
[But-bpy]). Anal. Found (calcd) for C33H46N6Zr: C, 63.55
(64.16); H, 7.55 (7.45); N, 13.17 (13.61).
Acknowledgment. We greatly appreciate the fi-
nancial support of the Office of Naval Research, the
donors of the Petroleum Research Fund, administered
by the American Chemical Society, the National Science
Foundation, the Department of Energy-Defense Pro-
grams, and Michigan State University. A.L.O. is an
Alfred P. Sloan Fellow.
Synthesis of Zr(NSiPh3)(dpma)(bpy) (10). To an orange
solution of Zr(NBut)(dpma)(bpy) (9; 433 mg, 0.70 mmol) in 10
mL of CH2Cl2 was added a colorless solution of H2NSiPh3 (193
mg, 0.70 mmol) in CH2Cl2 (5 mL). The reaction mixture was
stirred for 16 h, after which volatiles were removed in vacuo
to give a yellow solid. The solid was recrystallized from
CH2Cl2/pentane at -35 °C. Yield: 194 mg (34%). 1H NMR (300
MHz, CDCl3): δ 7.90 (2 H, s, 3,3′-[But-bpy]), 7.73 (2 H, s,
5-C4H3N), 7.48 (8 H, m, 2-C6H5 and 5,5′-[But-bpy]), 7.38
(2 H, s, 6,6′-[But-bpy]), 7.23-7.03 (10 H, m, 4-C6H5 and
3-C6H5), 6.14 (2 H, s, 4-C4H3N), 5.99 (2 H, s, 3-C4H3N), 3.85 (2
Supporting Information Available: Complete labeled
ORTEP diagrams and tables giving data for the X-ray diffrac-
tion studies on 1, 5, 6, 8, and 11; X-ray data are also available
as CIF files. This material is available free of charge via the
Internet at http://pubs.acs.org.
OM050179S