Functionalizing titanium-phosphinimide complexes

Article abstract of DOI:10.1021/om060565p

The reaction of the titanacycle CpTi(NPt-Bu₃)(C ₄H₈) (1) with benzyl halides, 4-bromo-l-butene, and allyl chloride proceeds with loss of ethylene to give CpTiX(NPt-Bu₃) (CH₂Ph) (X = Cl, 3; Br, 4), CpTiBr-(NPt-Bu₃)(CH ₂CH₂CHCH₂) (5), and CpTiCl(NPt-Bu ₃)(CH₂CHCH₂) (6), respectively. Complexes 4 and 6 were readily alkylated to CpTiMe(NPt-Bu₃)(CH₂Ph) (7) and CpTiMe(NPt-Bu₃)(CH₂CHCH₂) (8), respectively. Loss of ethylene also occurs on reaction of 1 with bipyridine to give CpTi(NPt-Bu₃)(bipy) (9). In contrast, reaction of 1 with ClSiMePh₂ in the presence of PMe₃ gave CpTiCl(NPt-Bu ₃)(CH₂CH₂-SiPh₂Me) (10). In a similar fashion, the two-carbon derivatives CpTiCl(NPt-Bu₃)(CH ₂CH₂SiMe₃) (11), CpTiCl(NPt-Bu ₃)(CH₂CH₂Si(SiMe₃)₃) (12), CpTi(NPt-Bu₃)(CH₂CH₂SiMe ₃)(OSO₂CF₃) (13), CpTiCl(NPt-Bu ₃)(CH₂CH₂Snn-Bu₃) (14), CpTiCl(NPt-Bu₃)(CH₂CH₂SiCl₃) (15), and [CpTiCl(NPt-Bu₃)(CH₂CH₂)]2-SiCl₂ (16) were produced. In the absence of PMe₃, reaction of 1 with SiCl₄ and ClSnMe₃ gave the four-carbon derivatives CpTiCl(NPt-Bu₃)(CH₂CH₂CH₂CH ₂SiCl₃) (17) and CpTiCl(NPt-Bu₃)(CH ₂CH₂CH₂CH₂-SnMe₃) (18), while reaction of 1 with ClSnPh₃ gave only the two-carbon chain derivative CpTiCl(NPt-Bu₃)(CH₂CH₂SnPh ₃) (19). Nonetheless, in the presence and absence of PMe₃ reaction of 1 with ClBcat or ClPPh₂ gave the analogous two- and four-carbon derivatives CpTiCl(NPt-Bu₃)(CH₂CH ₂Bcat) (20), CpTiCl(NPt-Bu₃)(CH₂CH ₂CH₂CH₂Bcat) (21), CpTiCl(NPt-Bu ₃)(CH₂CH₂PPh₂)(22), and CpTiCl(NPt-Bu₃)(CH₂CH₂CH₂CH ₂PPh₂) (23), respectively. The corresponding species CpTiCl(NPt-Bu₃)(CH₂CH-(CH₃)CH(CH ₃)CH₂PPh₂) (24) was prepared from CpTi(NPt-Bu₃)(CH₂CHMe)₂ (2), while complexation of 23 and 24 afforded CpTiCl(NPt-Bu₃)(CH₂CH ₂CH₂CH₂PPh₂)RhCl(cod) (25) and CpTiCl(NPt-Bu₃)(CH₂-CH(CH₃)CH(CH ₃)CH₂PPh₂)RhCl(cod) (26). The mechanisms affording the functionalized two- and four-carbon derivatives above are discussed and the implications considered.

Full text of DOI:10.1021/om060565p

Organometallics 2006, 25, 4779-4786
4779
Functionalizing Titanium-Phosphinimide Complexes
Peter Voth, Christopher Fraser, Todd Graham, Chunbao Zhu, James Gauld, and
Douglas W. Stephan*
Department of Chemistry and Biochemistry, UniVersity of Windsor, Windsor, Ontario, Canada, N9B3P4
ReceiVed June 27, 2006
The reaction of the titanacycle CpTi(NPt-Bu3)(C4H8) (1) with benzyl halides, 4-bromo-1-butene, and
allyl chloride proceeds with loss of ethylene to give CpTiX(NPt-Bu3)(CH2Ph) (X ) Cl, 3; Br, 4), CpTiBr-
(NPt-Bu3)(CH2CH2CHCH2) (5), and CpTiCl(NPt-Bu3)(CH2CHCH2) (6), respectively. Complexes 4 and
6 were readily alkylated to CpTiMe(NPt-Bu3)(CH2Ph) (7) and CpTiMe(NPt-Bu3)(CH2CHCH2) (8),
respectively. Loss of ethylene also occurs on reaction of 1 with bipyridine to give CpTi(NPt-Bu3)(bipy)
(9). In contrast, reaction of 1 with ClSiMePh2 in the presence of PMe3 gave CpTiCl(NPt-Bu3)(CH2CH2-
SiPh2Me) (10). In a similar fashion, the two-carbon derivatives CpTiCl(NPt-Bu3)(CH2CH2SiMe3) (11),
CpTiCl(NPt-Bu3)(CH2CH2Si(SiMe3)3) (12), CpTi(NPt-Bu3)(CH2CH2SiMe3)(OSO2CF3) (13), CpTiCl(NPt-
Bu3)(CH2CH2Snn-Bu3) (14), CpTiCl(NPt-Bu3)(CH2CH2SiCl3) (15), and [CpTiCl(NPt-Bu3)(CH2CH2)]2-
SiCl2 (16) were produced. In the absence of PMe3, reaction of 1 with SiCl4 and ClSnMe3 gave the four-
carbon derivatives CpTiCl(NPt-Bu3)(CH2CH2CH2CH2SiCl3) (17) and CpTiCl(NPt-Bu3)(CH2CH2CH2CH2-
SnMe3) (18), while reaction of 1 with ClSnPh3 gave only the two-carbon chain derivative CpTiCl(NPt-
Bu3)(CH2CH2SnPh3) (19). Nonetheless, in the presence and absence of PMe3 reaction of 1 with ClBcat
or ClPPh2 gave the analogous two- and four-carbon derivatives CpTiCl(NPt-Bu3)(CH2CH2Bcat) (20),
CpTiCl(NPt-Bu3)(CH2CH2CH2CH2Bcat) (21), CpTiCl(NPt-Bu3)(CH2CH2PPh2)(22), and CpTiCl(NPt-
Bu3)(CH2CH2CH2CH2PPh2) (23), respectively. The corresponding species CpTiCl(NPt-Bu3)(CH2CH-
(CH3)CH(CH3)CH2PPh2) (24) was prepared from CpTi(NPt-Bu3)(CH2CHMe)2 (2), while complexation
of 23 and 24 afforded CpTiCl(NPt-Bu3)(CH2CH2CH2CH2PPh2)RhCl(cod) (25) and CpTiCl(NPt-Bu3)(CH2-
CH(CH3)CH(CH3)CH2PPh2)RhCl(cod) (26). The mechanisms affording the functionalized two- and four-
carbon derivatives above are discussed and the implications considered.
Scheme 1
Introduction
Reviews in the recent literature have described the synthesis
and structure of phosphinimide complexes of transition metal
and main group elements1,2 as well as the development of early
metal-phosphinimide catalysts for olefin polymerization.3
Complexes in which the phosphinimide-nitrogen is accessible
have proved to be less active catalysts as they are attacked by
Lewis acids which subsequently effect C-H bond activation
processes,4-6 and undergo reduction to give phosphinimide-
bridged dimers.7 The participation of the ligand in the chemistry
can be eliminated by employing sterically demanding phos-
phinimide substituents. Such derivatized ligands offer highly
effective polymerization catalysts and are not deactivated by
Lewis acids. In these cases, it appears that the steric protection
provided by the substituents on P is comparable to that offered
by cyclopentadienyl ligands, and yet the displacement of such
steric protection from the metal by the intervening nitrogen atom
accommodates a reactive metal atom coordination sphere.
In a recent study probing the reactivity of systems containing
sterically demanding, ancillary phosphinimide ligands, we
showed that reduction of CpTi(NPt-Bu3)Cl2 by Mg was solvent
dependent. Reduction in benzene afforded the dimer [CpTi(NPt-
Bu3)(µ-Cl)]28 (Scheme 1), whereas reduction in THF generated
a putative Ti(II) species, which could be intercepted by olefins,
acetylenes, and CO.7 The resulting product intercepted by
ethylene, CpTi(NPt-Bu3)(CH2CH2)2 (Scheme 1), exhibits a
classical metallocyclic structure in the solid state. However, its
reactivity suggested this compound could act as a Ti(II) synthon
via loss of ethylene. In this paper, we probe the reactivity of
this species with a variety of alkyl and main group halides.
* To whom correspondence should be addressed. E-mail: stephan@
uwindsor.ca.
(1) Dehnicke, K.; Weller, F. Coord. Chem. ReV. 1997, 158, 103-169.
(2) Dehnicke, K.; Krieger, M.; Massa, W. Coord. Chem. ReV. 1999, 182,
19-65.
(3) Stephan, D. W. Organometallics 2005, 24, 2548-2560.
(4) Kickham, J. E.; Guerin, F.; Stephan, D. W. J. Am. Chem. Soc. 2002,
124, 11486-11494.
(5) Kickham, J. E.; Guerin, F.; Stewart, J. C.; Stephan, D. W. Angew.
Chem., Int. Ed. 2000, 39, 3263-3266.
(6) Kickham, J. E.; Guerin, F.; Stewart, J. C.; Urbanska, E.; Ong, C.
M.; Stephan, D. W. Organometallics 2001, 20, 1175-1182.
(7) Graham, T. W.; Kickham, J.; Courtenay, S.; Wei, P.; Stephan, D.
W. Organometallics 2004, 23, 3309-3318.
(8) Sung, R. C. W.; Courtenay, S.; McGarvey, B. R.; Stephan, D. W.
Inorg. Chem. 2000, 39, 2542-2546.
10.1021/om060565p CCC: $33.50 © 2006 American Chemical Society
Publication on Web 08/22/2006

4780 Organometallics, Vol. 25, No. 20, 2006
Voth et al.
29.5 (t-Bu3). 31P{1H} NMR: 39.8. Anal. Calcd for C20H37ClNPTi:
C, 59.19, H, 9.19, N, 3.45. Found: C, 59.37, H, 9.32, N, 3.64.
While alkyl halides are shown to afford products best described
as arising from oxidative addition to Ti(II), main group halides
react differently, affording main group addition to two- or four-
carbon chains on Ti. In this fashion, these synthetic strategies
offer new approaches to functionalized Ti-phosphinimide
complexes. Mechanistic implications of this reactivity are
considered in the light of preliminary DFT calculations.
Synthesis of CpTiMe(NPt-Bu3)(CH2Ph) (7) and CpTiMe(NPt-
Bu3)(CH2CHCH2) (8). These compounds were prepared in a
similar fashion, and thus one preparation is detailed. Compound 4
(87 mg, 0.17 mmol) was dissolved in 4 mL of toluene, and methyl
Grignard solution (57 µL, 3M in THF) was added at room
temperature. After 0.5 h the solvent was removed in vacuo and the
brown residue extracted with pentane. Cooling overnight (-35 °C)
afforded orange crystals (30 mg, 40%). 7: 1H NMR: 7.26 (t, 3JHH
) 8, 2 H, m-Ph), 7.03 (d, 3JHH ) 7, 2 H, o-Ph), 6.92 (t, 3JHH ) 8,
1 H, p-Ph), 6.01 (s, 5 H, Cp), 2.96, 2.36 (d, 2JHH ) 10, 1H, TiCH2),
Experimental Section
General Data. All preparations were done under an atmosphere
of dry, O2-free N2 employing both Schlenk line techniques and an
MBraun or Vacuum Atmospheres inert atmosphere glovebox.
Solvents were purified employing a Grubbs type solvent purification
system manufactured by Innovative Technologies. All organic
reagents were purified by conventional methods. 1H, 31P{1H},
11B{1H}, 29Si{1H}, and 13C{1H} NMR spectra were recorded on
Bruker Avance-300 and -500 spectrometers. All spectra were
recorded in C6D6 at 25 °C unless otherwise noted. For 1H and 13C-
{1H} NMR spectra, trace amounts of protonated solvents were used
as reference, and chemical shifts are reported relative to SiMe4.
31P{1H}, 11B{1H}, and 29Si{1H} NMR spectra were referenced to
external 85% H3PO4, BF3‚Et2O, and SiMe4, respectively. Chemical
shifts are reported in ppm and coupling constants in Hz. Combustion
analyses were performed in-house employing a Perkin-Elmer CHN
analyzer. CpTi(NPt-Bu3)Cl2, CpTi(NPt-Bu3)(CH2CH2)2 (1), and
CpTi(NPt-Bu3)(CH2CHMe)2 (2) were prepared according to pub-
lished procedures.3,9 Alkyl, Si, Sn, P, and B halides employed herein
were purchased from Aldrich Chemical Co. and used as received.
Synthesis of CpTiX(NPt-Bu3)(CH2Ph) (X ) Cl, 3; Br, 4),
CpTiBr(NPt-Bu3)(CH2CH2CHCH2) (5), and CpTiCl(NPt-Bu3)-
(CH2CHCH2) (6). These compounds were prepared in a similar
fashion using the appropriate alkyl halide reagent, and thus only
one example is detailed. Compound 1 (261 mg, 0.68 mmol) was
dissolved in 6 mL of toluene, and PMe3 (270 µL, 2.61 mmol) and
benzyl bromide (81 µL, 0.68 mmol) were added at room temper-
ature. After 2 h the solvent was removed in vacuo to yield 220 mg
(65%) of the product 4. It was subsequently shown that addition
of PMe3 is not required and its presence had no effect on the yield.
3
1.18 (d, JPH ) 13, 27 H, t-Bu3), 0.77 (s, 3 H, TiMe). 13C{1H}
NMR (partial): 153.0, 126.2, 120.5 (Ph), 112.1 (Cp), 69.0 (TiCH2),
1
42.1 (TiMe), 41.3 (d, JPC ) 47, t-Bu3), 29.6 (t-Bu3). 31P{1H}
NMR: 34.1. Anal. Calcd for C25H42NPTi: C, 68.95, H, 9.72, N,
3.22. Found: C, 68.20, H, 9.92, N, 3.17. Preliminary X-ray data:
a ) 20.194(4) Å, b ) 14.670(3) Å, c ) 8.578(2) Å, orthorhombic
1
space group: Pna21. 8: Yield: 22% (brown powder). H NMR:
6.37 (quin, 3JHH ) 11, 1 H, C3H5), 6.18 (s, 5 H, Cp), 3.52 (d, 3JHH
3
) 11, 4 H, C3H5), 1.15 (d, JPH ) 13, 27 H, t-Bu3), 0.72 (s, 3 H,
TiCH3). 13C{1H} NMR: 148.3 (C3H5), 111.8 (Cp), 84.2 (C3H5),
1
41.3 (d, JPC ) 49, t-Bu3), 39.9 (TiCH3), 29.6 (t-Bu3). 31P{1H}
NMR: 31.6. Anal. Calcd for C21H40NPTi: C, 65.44, H, 10.46, N,
3.63. Found: C, 65.21, H, 10.33, N, 3.47.
Synthesis of CpTi(NPt-Bu3)(bipy) (9). The titanacycle 1 (242
mg, 0.62 mmol) and 2,2′-bipyridyl (98 mg, 0.62 mmol) were
dissolved in 6 mL of toluene at room temperature. The dark blue
solution was stirred for 2 h. After filtration through Celite the
solvent was removed partly in vacuo. Cooling overnight afforded
dark blue crystals in 61% yield (185 mg). 1H NMR: 7.49 (br d, 2
3
H, bipy), 7.29 (d, JHH ) 9, 2 H, bipy), 6.43 (s, 5 H, Cp), 5.31,
3
1
4.03 (br m, 2 H, bipy), 1.02 (d, JHH ) 12, 27 H, t-Bu). H NMR
(-80 °C, toluene-d8): 7.43 (d, 3JHH ) 6, 2 H, bipy), 7.34 (d, 3JHH
) 9, 2 H, bipy), 6.37 (br t, 2 H, bipy), 6.31 (s, 5 H, Cp), 5.35 (t,
3JHH ) 6, 2 H, bipy), 1.02 (br d, 18 H, t-Bu), 0.83 (br d, 9 H,
t-Bu).13C{1H} NMR: 149.5, 116.6 (bipy), 109.6 (Cp), 40.4 (d, 1JPC
) 46, t-Bu). More signals of the bipy ligand were not detected.
Dept135 (-30 °C, toluene-d8): 149.9, 125.8, 121.9, 104.9 signals
detected for the bipy ligand. 31P{1H} NMR: 33.8. Anal. Calcd for
C27H40N3PTi: C, 66.80, H, 8.30, N, 8.66. Found: C, 65.94, H,
8.29, N, 8.58.
1
3: Yield: 44%. H NMR: 7.40 (m, 4 H, Ph), 7.02 (m, 1 H, Ph),
2
6.17 (s, 5 H, Cp), 3.79, 2.79 (d, JHH ) 10, 1 H, TiCH2), 1.24 (d,
3JPH ) 13, 27 H, t-Bu3). 13C{1H} NMR: 152.4, 127.4, 121.5, 115.0
1
(Ph), 113.7 (Cp), 71.4 (TiCH2), 41.5 (d, JPC ) 45, t-Bu3), 29.5
Synthesis of CpTiCl(NPt-Bu3)(CH2CH2SiPh2Me) (10), Cp-
TiCl(NPt-Bu3)(CH2CH2SiMe3) (11), CpTiCl(NPt-Bu3)(CH2CH2Si-
(SiMe3)3) (12), CpTi(NPt-Bu3)(CH2CH2SiMe3)(OSO2CF3) (13),
CpTiCl(NPt-Bu3)(CH2CH2Snn-Bu3) (14), CpTiCl(NPt-Bu3)-
(CH2CH2SiCl3) (15), and [CpTiCl(NPt-Bu3)(CH2CH2)]2SiCl2
(16). These compounds were prepared in a similar fashion using
the appropriate alkyl halide reagent and stoichiometry, and thus
only one example is detailed. Complex 1 (625 mg, 1.62 mmol)
was dissolved in 8 mL of pentane, and 600 µL (5.80 mmol) of
PMe3 was added. After 5 min ClSiMePh2 (341 µL, 1.63 mmol)
was added at room temperature and stirred for 3 h. After filtration
through Celite the solvent was removed partly in vacuo. Cooling
overnight afforded red-brown crystals in 59% yield (559 mg). 10:
1H NMR: 7.66 (br t, 4 H, o-SiPh2), 7.22 (br t, 6 H, p-SiPh2,
m-SiPh2), 6.25 (s, 5 H, Cp), 2.30, 1.47 (br dt, 1 H, TiCH2), 1.81
(m, 2 H, TiCH2CH2Si), 1.13 (d, 3JPH ) 13, 27 H, t-Bu), 0.59 (s, 3
H, SiMe). 13C{1H} NMR: 139.0, 138.8, 135.2, 135.1, 129.0 (SiPh2),
(t-Bu3). 31P{1H} NMR: 40.2. 4: Yield: 65%. 1H NMR: 7.29 (m,
2
4 H, Ph), 6.95 (m, 1 H, Ph), 6.10 (s, 5 H, Cp), 3.55, 2.59 (d, JHH
) 10, 1 H, TiCH2), 1.17 (d, 3JPH ) 13, 27 H, t-Bu3). 13C{1H} NMR
(partial): 152.3, 127.4, 121.5 (Ph), 114.0 (Cp), 74.7 (TiCH2), 41.6
(d, 1JPC ) 42, t-Bu3), 29.6 (t-Bu3). 31P{1H} NMR: 42.0. Anal. Calcd
for C24H39BrNPTi: C, 57.61, H, 7.86, N, 2.80. Found: C, 57.04,
H, 8.10, N, 2.21. Preliminary X-ray data: a ) 14.727(6) Å, b )
17.836(7) Å, c ) 17.836(8) Å, orthorhombic space group not
unambiguously determined. 5: Yield: 74%. X-ray-quality crystals
1
were obtained via recrystallization from toluene. H NMR: 6.28
(s, 5 H, Cp), 5.99 (m, 1 H, CHCH2), 5.09, 4.94 (m, 1 H, CHCH2),
2
3
2.63 (m, 2 H, TiCH2CH2), 2.13, 1.61 (dt, JHH ) 5, JHH ) 11, 1
H, TiCH2), 1.16 (d, 3JPH ) 13, 27 H, t-Bu3). 13C{1H} NMR: 144.0
(CHCH2), 111.1 (CHCH2), 112.5 (Cp), 68.8 (TiCH2), 41.4 (d, 1JPC
) 45, t-Bu3), 39.0 (TiCH2CH2), 29.6 (t-Bu3). 31P{1H} NMR: 39.5.
Anal. Calcd for C21H39BrNPTi: C, 54.32, H, 8.47, N, 3.02.
Found: C, 54.53, H, 8.66, N, 2.99. 6: Yield: 59%. 1H NMR: 6.50
1
112.4 (Cp), 60.6 (TiCH2), 41.4 (d, JPC ) 45, t-Bu), 29.5 (t-Bu),
3
3
(quin, JHH ) 11, 1 H, C3H5), 6.27 (s, 5 H, Cp), 3.82 (d, JHH
)
21.1 (TiCH2CH2Si), -4.1 (SiMe). 31P{1H} NMR: 37.8, 29Si{1H}
NMR: -8.6. Anal. Calcd for C32H49ClNPSiTi: C, 65.13, H, 8.37,
11, 4 H, C3H5), 1.14 (d, JPH ) 13, 27 H, t-Bu3). 13C{1H} NMR:
146.5 (C3H5), 114.0 (Cp), 87.1 (C3H5), 41.5 (d, 1JPC ) 45, t-Bu3),
3
1
N, 2.37. Found: C, 65.72, H, 8.60, N, 2.34. 11: Yield: 95%. H
NMR: 6.28 (s, 5 H, Cp), 2.12, 1.61 (m, 1 H, TiCH2), 1.25 (m, 2
(9) Stephan, D. W.; Stewart, J. C.; Guerin, F.; Courtenay, S.; Kickham,
J.; Hollink, E.; Beddie, C.; Hoskin, A.; Graham, T.; Wei, P.; Spence, R. E.
v. H.; Xu, W.; Koch, L.; Gao, X.; Harrison, D. G. Organometallics 2003,
22, 1937-1947.
3
H, TiCH2CH2Si), 1.18 (d, JPH ) 13, 27 H, t-Bu), 0.10 (s, 9 H,
SiMe3). 13C{1H} NMR: 112.5 (Cp), 62.2 (TiCH2), 41.5 (d, 1JPC
)
45, t-Bu), 29.6 (t-Bu), 24.6 (TiCH2CH2Si), -1.6 (SiMe). 31P{1H}

Functionalizing Titanium-Phosphinimide Complexes
Organometallics, Vol. 25, No. 20, 2006 4781
NMR: 37.6. 29Si{1H} NMR: -31.0. Anal. Calcd for C22H45-
was added. The reaction mixture was filtered through Celite and
cooled overnight, affording a brown powder in 52% yield (171 mg).
1H NMR: 7.05 (m, 2 H, O2C6H4), 6.78 (m, 2 H, O2C6H4), 6.27 (s,
5 H, Cp), 2.35, 1.82 (m, 1 H, TiCH2), 1.93 (m, 2 H, TiCH2CH2B),
ClNPSiTi: C, 56.71, H, 9.73, N, 3.01. Found: C, 56.39, H, 9.60,
1
N, 3.34. 12: Yield: 100%. H NMR: 6.30 (s, 5 H, Cp), 2.37 (m,
3
2 H, TiCH2), 1.63 (m, 2 H, SiCH2), 1.23 (d, JP-H ) 12, 27 H,
3
t-Bu), 0.35 (s, 27 H, SiMe); 13C{1H} NMR: 112.3 (Cp), 69.0
1.16 (d, JPH ) 13, 27 H, t-Bu). 11B{1H} NMR: 34.6. 13C{1H}
1
(TiCH2), 41.5 (d, JP-C ) 46, t-Bu), 29.7 (t-Bu), 15.1 (CH2Si),
NMR: 149.3, 122.4, 112.4 (O2C6H4), 112.6 (Cp), 58.0 (TiCH2),
41.4 (d, 1JPC ) 45, t-Bu), 30.0 (TiCH2CH2B), 29.6 (t-Bu). 31P{1H}
NMR: 38.9. Anal. Calcd for C25H40BClNO2PTi: C, 58.68, H, 7.88,
N, 2.74. Found: C, 58.26, H, 8.03, N, 2.78.
1.78(SiMe3), 31P{1H} NMR: 38.5, 29Si{1H} NMR: -13.1, -79.3.
Anal. Calcd for C28H63ClNPSi4Ti: C, 52.51, H, 9.92, N, 2.19.
1
Found: C, 52.72, H, 9.78, N, 2.34. 13: Yield: 100%. H NMR:
6.30 (s, 5 H, Cp), 2.18 (m, 2 H, TiCH2), 1.70 (m, 2 H, SiCH2),
Synthesis of CpTiCl(NPt-Bu3)(CH2CH2CH2CH2Bcat) (21).
Compound 1 (203 mg, 0.52 mmol) was dissolved in 3 mL of
pentane, and a solution of B-chlorocatecholborane (81 mg, 0.52
mmol) in 3 mL of pentane was added dropwise. The reaction
mixture was filtered through Celite and cooled overnight, affording
the product as a yellow solid (about 25 mg) and oil (about 173
3
1.08 (d, JP-H ) 12, 27 H, t-Bu), 0.11 (s, 9 H, SiMe). 13C{1H}
NMR: 112.0 (Cp), 65.6 (TiCH2), 41.0 (d, 1JP-C ) 46, t-Bu), 29.5
(t-Bu), 21.9 (CH2Si), 1.1 (SiMe3). 31P{1H} NMR: 43.2. 29Si{1H}
NMR: -31.5. Anal. Calcd for C23H45F3O3NPSiTi: C, 47.66, H,
7.83, N, 2.42. Found: C, 47.52, H, 7.67, N, 2.31. 14: Yield: 78%
(dark red oil). 1H NMR: 6.31 (s, 5 H, Cp), 2.43 (m, 1 H, TiCH2),
1.75 (m, 9 H, SnCH2 + TiCH2), 1.44 (m, 12 H, SnCH2(CH2)2-
1
mg) in 62% yield (spectroscopically identical). H NMR: 7.02,
6.80 (m, 2 H, O2C6H4), 6.25 (s, 5 H, Cp), 2.11, 1.71 (m, 1 H,
TiCH2), 1.95 (m, 2 H, TiCH2CH2), 1.68 (m, 2 H, CH2CH2B), 1.27
(br t, 2 H, CH2B), 1.17 (d, 3JPH ) 13, 27 H, t-Bu). 11B{1H} NMR:
35.4. 13C{1H} NMR: 149.0, 122.6, 112.5 (O2C6H4), 112.3 (Cp),
3
CH3), 1.22 (d, JPH ) 13, 27 H, t-Bu), 1.00 (br d, 9 H,
Sn(CH2)3CH3). 13C{1H} NMR: 112.3 (Cp), 67.7 (TiCH2), 41.6 (d,
1JPC ) 46, t-Bu), 30.0, 28.0, 14.1, 9.5 (n-Bu), 29.7 (t-Bu), 18.0
(SnCH2). 31P{1H} NMR: 37.6. Anal. Calcd for C31H63ClNPSnTi:
C, 54.52, H, 9.70, N, 2.05. Found: C, 54.12, H, 9.29, N, 2.04. 15:
1
68.4 (TiCH2), 42.0 (d, JPC ) 45, t-Bu), 39.7 (TiCH2CH2), 29.6
(t-Bu), 10.4 (CH2CH2B). The resonance for the CH2CH2B group
is covered by the signal of the t-Bu group. 31P{1H} NMR: 38.3.
Anal. Calcd for C27H44BClNO2PTi: C, 60.08, H, 8.22, N, 2.59.
Found: C, 59.84, H, 8.15, N, 2.78.
1
Yield: 78%. H NMR: 6.12 (s, 5 H, Cp), 2.07, 1.45 (m, 1 H,
3
TiCH2), 1.95 (m, 2 H, TiCH2CH2Si), 1.12 (d, JPH ) 13, 27 H,
1
t-Bu). 13C{1H} NMR: 112.8 (Cp), 47.9 (TiCH2), 41.5 (d, JPC
)
46, t-Bu), 29.6 (t-Bu), 26.3 (TiCH2CH2Si). 31P{1H} NMR: 40.7.
29Si NMR: -31.5. Anal. Calcd for C19H36Cl4NPSiTi: C, 43.28,
H, 6.88, N, 2.66. Found: C, 44.38, H, 7.20, N, 2.70. 16: Yield:
Synthesis of CpTiCl(NPt-Bu3)(CH2CH2PPh2) (22). The titana-
cycle 1 (259 mg, 0.67 mmol) was dissolved in 5 mL of toluene,
260 µL (2.51 mmol) of PMe3 was added, and the solution was
cooled to -35 °C. After 20 min ClPPh2 (121 µL, 0.67 mmol) was
added, and the solution was allowed to warm to room temperature
slowly. After 2 h evaporation of solvent afforded a brown oil. The
oil was suspended in 6 mL of pentane and stirred for 5 min. A
yellow powder formed, which was isolated by decanting the pentane
by pipet. The powder was dried in vacuo (258 mg, 70%). 1H
NMR: 7.67, 7.60 (br t, 4 H, o-PPh2), 7.19 (br t, 2 H, p-PPh2), 7.12
(m, 4 H, m-PPh2), 6.18 (s, 5 H, Cp), 2.78 (m, 2 H, PCH2), 2.38,
1
44%. H NMR: 6.27 (s, 10 H, Cp), 2.15, 1.72 (m, 2 H, TiCH2),
1.91 (m, 4 H, TiCH2CH2Si), 1.20 (d, 3JPH ) 13, 27 H, t-Bu). 13C-
{1H} NMR: 112.7 (Cp), 54.0 (TiCH2), 41.5 (d, JPC ) 45, t-Bu),
1
30.1 (TiCH2CH2Si), 29.5 (t-Bu). 31P{1H} NMR: 40.7. Anal. Calcd
for C38H72Cl4N2P2SiTi: C, 51.59, H, 8.20, N, 3.17. Found: C,
50.98, H, 8.22, N, 3.19.
Synthesis of CpTiCl(NPt-Bu3)(CH2CH2CH2CH2SiCl3) (17),
CpTiCl(NPt-Bu3)(CH2CH2CH2CH2SnMe3) (18), and CpTiCl-
(NPt-Bu3)(CH2CH2SnPh3) (19). These compounds were prepared
in a similar fashion using the appropriate alkyl halide reagent, and
thus only one example is detailed. The titanacycle 1 (189 mg, 0.49
mmol) and ClSnPh3 (189 mg, 0.49 mmol) were dissolved in a
mixture of 5 mL of pentane and 1 mL of THF. After 3 h at room
temperature without stirring red crystals of 19 in 49% yield (185
mg) were obtained. 17: Yield: 62%. 1H NMR: 6.25 (s, 5 H, Cp),
3
1.47 (m, 1 H, TiCH2), 1.08 (d, JPH ) 13, 27 H, t-Bu). 13C{1H}
NMR: 133.9, 133.7, 133.4, 133.2, 128.4 (PPh2), 112.3 (Cp), 59.5
(TiCH2), 41.3 (d, 1JPC ) 46, t-Bu), 33.6 (br m, PCH2), 29.4 (t-Bu).
31P{1H} NMR: 39.1 (NPt-Bu3), -8.7 (PPh2). Anal. Calcd for
C31H46ClNP2Ti: C, 64.42, H, 8.02, N, 2.42. Found: C, 64.77, H,
7.98, N, 2.48.
Synthesis of CpTiCl(NPt-Bu3)(CH2CH2CH2CH2PPh2) (23)
and CpTiCl(NPt-Bu3)(CH2CH(CH3)CH(CH3)CH2PPh2) (24).
These compounds were prepared in a similar fashion using 1 and
2 as starting materials, and thus only one example is detailed. The
titanacycle 1 (299 mg, 0.77 mmol) was dissolved in 5 mL of toluene
and cooled to -35 °C. After 20 min ClPPh2 (140 µL, 0.77 mmol)
was added, and the solution was allowed to warm to room
temperature slowly. After 2 h evaporation of the solvent afforded
a brown oil. The oil was suspended in 6 mL of pentane and stirred
for 5 min. A yellow powder formed, which was isolated by
decanting the overlaying solution by pipet. The powder 20 was
dried in vacuo (299 mg, 67%). 23: 1H NMR: 7.50, 7.48 (br t, 4
H, o-PPh2), 7.10 (br t, 4 H, m-PPh2), 7.07 (m, 2 H, p-PPh2), 6.26
2
3
2.03, 1.49 (dt, JHH ) 5, JHH ) 11, 1 H, TiCH2), 1.76 (m, 2 H,
3
TiCH2CH2), 1.44 (m, 2 H, CH2CH2Si), 1.16 (d, JPH ) 13, 27 H,
t-Bu). The signal for CH2 attached to Si is covered by the resonance
of the t-Bu group. 13C{1H} NMR: 112.2 (Cp), 65.8 (TiCH2), 41.2
1
(d, JPC ) 46, t-Bu), 36.7 (TiCH2CH2), 29.6 (t-Bu), 27.5 (CH2-
CH2Si), 23.8 (CH2CH2Si). 31P{1H} NMR: 39.4. 18: Yield: 73%
(dark red oil). 1H NMR: 6.30 (s, 5 H, Cp), 2.22 (dt, 2JHH ) 5, 3JHH
) 11, 1 H, TiCH2), 1.91 (m, 2 H, TiCH2CH2), 1.77 (dt, 2JHH ) 5,
3
3JHH ) 11, 1 H, TiCH2), 1.60 (m, 2 H, CH2CH2Sn), 1.19 (d, JPH
) 13, 27 H, t-Bu), 0.94 (m, 2 H, CH2CH2Sn), 0.13 (t, 3JSnH ) 26,
9 H, SnMe3). 13C{1H} NMR: 112.3 (Cp), 69.4 (TiCH2), 41.5 (d,
1JPC ) 45, t-Bu), 39.9 (TiCH2CH2), 32.7 (CH2CH2Sn), 29.7 (t-
Bu), 11.2 (CH2CH2Sn), 10.2 (SnMe3). 31P{1H} NMR: 38.2. 19:
2
3
(s, 5 H, Cp), 2.13, 1.74 (dt, JHH ) 5, JHH ) 11, 1 H, TiCH2),
2.10 (br t, 2 H, PCH2), 2.01, 1.95 (m, 1 H, TiCH2CH2), 1.57 (m,
1
Yield: 49%. H NMR: 7.71 (m, 6 H, o-SnPh3), 7.21 (m, 9 H,
3
2 H, PCH2CH2), 1.15 (d, JPH ) 13, 27 H, t-Bu). 13C{1H} NMR:
m-SnPh3 + p-SnPh3), 6.26 (s, 5 H, Cp), 2.63 (m, 1 H, TiCH2),
3
2.34 (m, 2 H, SnCH2), 1.71 (m, 1 H, TiCH2), 1.10 (d, JPH ) 13,
134.8, 133.2, 128.6, 128.5, 128.4, 128.3 (PPh2), 112.3 (Cp), 68.4
27 H, t-Bu). 13C{1H} NMR: 141.0, 137.8, 129.0 (SnPh3), 112.4
(TiCH2), 41.5 (d, 1JPC ) 46, t-Bu), 36.7 (d, 3JPC ) 11, TiCH2CH2),
1
2
(Cp), 64.1 (TiCH2), 41.4 (d, JPC ) 45, t-Bu), 29.5 (t-Bu), 18.8
31.9 (d, JPC ) 16, PCH2CH2), 29.4 (t-Bu), 28.9 (br m, PCH2).
(SnCH2). 31P{1H} NMR: 38.3. Anal. Calcd for C37H51ClNPSnTi:
31P{1H} NMR: 38.1 (NPt-Bu3), -15.2 (PPh2). Anal. Calcd for
C, 59.83, H, 6.92, N, 1.89. Found: C, 59.40, H, 7.13, N, 1.88.
C33H50ClNP2Ti: C, 65.40, H, 8.32, N, 2.31. Found: C, 65.10, H,
1
Synthesis of CpTiCl(NPt-Bu3)(CH2CH2Bcat) (20). Compound
1 (248 mg, 0.64 mmol) was dissolved in 3 mL of pentane, and
PMe3 (about 200 µL) was added. After 5 min a solution of
B-chlorocatecholborane (100 mg, 0.64 mmol) in 3 mL of pentane
8.38, N, 2.35. 24: Yield: 131 mg, 47%, (a brown oil). H NMR:
7.63, 7.56 (br t, 4 H, o-PPh2), 7.13 (m, 6 H, m-PPh2), 6.97 (m, 2
H, p-PPh2), 6.20 (s, 5 H, Cp), 2.25 (m, 2 H, PCH2), 2.02 (m, 2 H,
TiCH2 + TiCH2CH), 1.56 (m, 1 H, CHCH2P), 1.34 (d, 2JHH ) 13,

4782 Organometallics, Vol. 25, No. 20, 2006
Voth et al.
3 H, TiCH2CHCH3), 1.16 (d, 3JPH ) 13, 27 H, t-Bu), 1.00 (d, 2JHH
) 13, 3 H, CH3CHCH2P). 13C{1H} NMR: 134.8, 133.8, 133.1,
employing the SHELXTL direct methods routine. The remaining
non-hydrogen atoms were located from successive difference
Fourier map calculations. The refinements were carried out by using
full-matrix least-squares techniques on F, minimizing the function
3
128.7 (PPh2), 112.3 (Cp), 75.9 (TiCH2), 43.7 (br d, JPC ) 7,
1
2
TiCH2CH), 41.6 (d, JPC ) 45, t-Bu), 36.3 (br d, JPC ) 11,
3
2
2
PCH2CH), 29.6 (t-Bu), 18.8 (TiCH2CHCH3), 15.7 (d, JPC ) 8,
w(|Fo| - |Fc|)2, where the weight w is defined as 4Fo /2σ(Fo ) and
Fo and Fc are the observed and calculated structure factor
amplitudes. In the final cycles of each refinement, all non-hydrogen
atoms were assigned anisotropic temperature factors in the absence
of disorder or insufficient data. In the latter cases, atoms were treated
isotropically. C-H atom positions were calculated and allowed to
ride on the carbon to which they are bonded, assuming a C-H
bond length of 0.95 Å. H atom temperature factors were fixed at
1.10 times the isotropic temperature factor of the C atom to which
they are bonded. The H atom contributions were calculated, but
not refined. The locations of the largest peaks in the final difference
Fourier map calculation as well as the magnitude of the residual
electron densities in each case were of no chemical significance.
Additional details are deposited.
CH3CHCH2P). The signal for the CH2 group attached to P was not
detected. 31P{1H} NMR: 37.7 (NPt-Bu3), -18.6 (br s, PPh2). Anal.
Calcd for C35H54ClNP2Ti: C, 66.30, H, 8.58, N, 2.21. Found: C,
66.10, H, 8.38, N, 2.15.
Synthesis of CpTiCl(NPt-Bu3)(CH2CH2CH2CH2PPh2)RhCl-
(cod)(25)andCpTiCl(NPt-Bu3)(CH2CH(CH3)CH(CH3)CH2PPh2)-
RhCl(cod) (26). These compounds were prepared in a similar
fashion using 23 and 24 as starting materials, and thus only one
example is detailed. Compound 23 (95 mg, 0.16 mmol) and [(cod)-
RhCl]2 (41 mg, 0.16 mmol) were mixed and dissolved in 2.5 mL
of toluene. After 15 min the solvent was removed in vacuo and
the oily residue was suspended in 4 mL of pentane. The overlaying
solution was transferred by pipet, and a yellow powder was isolated
(118 mg, 87%) after drying in vacuo. 25: 1H NMR: 7.74, 7.70 (br
t, 4 H, o-PPh2), 7.03 (m, 6 H, m-PPh2, p-PPh2), 6.44 (s, 5 H, Cp),
5.83, 3.12 (m, 2 H, cod), 2.67 (m, 2 H, PCH2), 2.18 (m, 3 H, cod
+ PCH2CH2), 2.07 (m, 7 H, cod + TiCH2CH2 + TiCH2), 1.94 (m,
1 H, TiCH2), 1.72 (m, 2 H, cod), 1.61 (m, 1 H, PCH2CH2), 1.19
Computations. All DFT calculations were performed using the
Gaussian 03 suite of programs.11 The basis set consisted of the
LANL2DZ basis set on Ti in combination with the 6-31G(d) basis
set12-15 on the all other atom types.
3
(d, JPH ) 13, 27 H, t-Bu). 13C{1H} NMR: 134.3, 134.2, 134.1,
Results and Discussion
133.8, 129.8, 129.7, 128.3 (PPh2), 112.4 (Cp), 104.4 (m, cod), 69.8
(d, 1JRhC ) 14, cod), 69.7 (d, 1JRhC ) 14, cod), 67.8 (TiCH2), 41.5
(d, 1JPC ) 45, t-Bu), 37.0 (d, 3JPC ) 14, TiCH2CH2), 33.3 (d, 2JPC
We have previously reported the synthesis of the titanacycles
CpTi(NPt-Bu3)(C4H8) (1) and CpTi(NPt-Bu3)(CH2CHMe)2 (2)
from the reduction of the precursor dichloride in the presence
of ethylene and propylene, respectively. Structural data showed
these compounds are best formulated as Ti(IV) metallacycles.7
Nonetheless, herein we demonstrate that these compounds are
indeed quite reactive. For example, reaction of compound 1 with
PMe3 in toluene followed by addition of benzyl chloride or
benzyl bromide proceeds at room temperature to give the
products 3 and 4 in 44% and 65% yield, respectively. It was
subsequently shown that addition of PMe3 was not required to
) 29, PCH2CH2), 32.0, 29.2, 29.0 (cod), 29.7 (t-Bu), 28.0 (d, 3JPC
1
) 25, PCH2). 31P{1H} NMR: 38.4 (NPt-Bu3), 27.8 (d, JRhP
)
149, PPh2). Anal. Calcd for C41H62Cl2NP2RhTi: C, 57.76, H, 7.33,
N, 1.64. Found: C, 57.75, H, 7.35, N, 1.40. 26: Yield: 171 mg,
1
3
44% (brown powder). H NMR: 7.99, 7.81 (br t, JHH ) 9, 2 H,
o-PPh2), 7.06 (m, 6 H, m-PPh2, p-PPh2), 6.29 (s, 5 H, Cp), 5.85
(m, 2 H, cod), 3.27, 3.19 (br s, 1 H, cod), 2.83 (m, 2 H, PCH2),
2.55 (m, 1 H, TiCH2CH), 2.42 (m, 1 H, TiCH2), 2.35 (m, 1 H,
PCH2CH), 2.21, 1.65 (m, 4 H, cod), 1.56 (m, 1 H, TiCH2), 1.47
(d, 3JHH ) 7, 3 H, TiCH2CHCH3), 1.19 (d, 3JPH ) 13, 27 H, t-Bu),
1
form these products. In both cases the H, 13C{1H}, and 31P-
3
1.04 (d, JHH ) 7, 3 H, PCH2CHCH3). 13C{1H} NMR: 135.0 (d,
{1H} NMR spectra were consistent with the formulation of 3
and 4 as CpTiX(NPt-Bu3)(CH2Ph) (X ) Cl, 3; Br, 4) (Scheme
2). In the case of 4, preliminary X-ray data were consistent with
this formulation, although the poor quality of the data precluded
a publishable solution. A similar reaction of 4-bromo-1-butene
with 1 proceeds to give 74% isolated yield of the product 5
formulated on the basis of NMR data as CpTiBr(NPt-Bu3)(CH2-
CH2CHCH2) (5) (Scheme 2). The nature of the pendant olefinic
fragment is consistent with the observations of 1H NMR
JPC ) 11), 134.6 (d, JPC ) 10), 134.2 (d, JPC ) 10), 129.8 (d, JPC
) 17), 129.3, 128.2 (PPh2), 112.4 (Cp), 103.6 (m, cod), 76.5
(TiCH2), 70.0 (d, 1JRhC ) 14, cod), 69.7 (d, 1JRhC ) 14, cod), 45.4
(d, 2JPC ) 9, PCH2CH), 41.6 (d, 1JPC ) 46, t-Bu), 36.3 (TiCH2CH),
3
2
35.0 (d, JPC ) 23, PCH2), 33.3 (d, JRhC ) 24, cod), 29.7 (t-Bu),
29.1 (d, 2JRhC ) 14, cod), 18.8 (TiCH2CHCH3), 16.7 (br s, PCH2-
CHCH3). 31P{1H} NMR: 38.5 (NPt-Bu3), 25.0 (d, JRhP ) 148,
1
PPh2). Anal. Calcd for C43H66Cl2NP2RhTi: C, 58.65, H, 7.55, N,
1.59. Found: C, 58.65, H, 7.84, N, 1.59.
X-ray Data Collection and Reduction. Crystals were manipu-
lated and mounted in capillaries in a glovebox, thus maintaining a
dry, O2-free environment for each crystal. Diffraction experiments
were performed on a Siemens SMART System CCD diffractometer.
A hemisphere of data was collected in 1329 frames with 10 s
exposure times. The observed extinctions were consistent with the
space groups in each case. The data sets were collected (4.5° < 2θ
< 45-50.0°). A measure of decay was obtained by re-collecting
the first 50 frames of each data set. The intensities of reflections
within these frames showed no statistically significant change over
the duration of the data collections. The data were processed using
the SAINT and XPREP processing packages. An empirical absorp-
tion correction based on redundant data was applied to each data
set. Subsequent solution and refinement was performed using the
SHELXTL solution package.
(11) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb,
M. A.; Cheeseman, J. R.; Montgomery, J. A., Jr.; Vreven, T.; Kudin, K.
N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.;
Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.;
Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.;
Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li,
X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Bakken, V.; Adamo, C.;
Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.;
Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.;
Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.; Dapprich,
S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.; Rabuck, A.
D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A.
G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.;
Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham,
M. A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.;
Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian
03; Gaussian, Inc.: Wallingford, CT, 2004.
(12) Ditchfield, R.; Hehre, W. J.; Pople, J. A. J. Chem. Phys. 1971, 54,
724-728.
Structure Solution and Refinement. Non-hydrogen atomic
scattering factors were taken from the literature tabulations.10 The
heavy atom positions were determined using direct methods
(13) Hehre, W. J.; Ditchfield, R.; Pople, J. A. J. Chem. Phys. 1972, 56,
2257-2261.
(14) Hariharan, P. C.; Pople, J. A. Theor. Chim. Acta 1973, 28, 213-
(10) Cromer, D. T.; Waber, J. T. Int. Tables X-ray Crystallogr. 1974, 4,
71-147.
222.
(15) Hariharan, P. C.; Pople, J. A. Mol. Phys. 1974, 27, 209-214.

Functionalizing Titanium-Phosphinimide Complexes
Organometallics, Vol. 25, No. 20, 2006 4783
Figure 1. ORTEP drawing of the cation of 5; 30% thermal
ellipsoids are shown. Hydrogen atoms are omitted for clarity.
Distances (Å) and angles (deg): Ti(1)-N(1) 1.777(4), Ti(1)-C(18)
2.176(6), Ti(1)-Br(1) 2.4512(11), P(1)-N(1) 1.594(4), C(20)-
C(21) 1.237(12), N(1)-Ti(1)-C(18) 99.5(2), N(1)-Ti(1)-Br(1)
104.60(13), C(18)-Ti(1)-Br(1) 97.63(17), P(1)-N(1)-Ti(1) 175.4-
(3).
Figure 2. ORTEP drawing of the cation of 9; 30% thermal
ellipsoids are shown. Hydrogen atoms are omitted for clarity.
Distances (Å) and angles (deg): Ti(1)-N(1) 1.834(3), Ti(1)-N(2)
2.044(3), Ti(1)-N(3) 2.055(3), P(1)-N(1) 1.577(3), N(2)-C(18)
1.362(5), N(2)-C(22) 1.396(5), N(3)-C(27) 1.360(5), N(3)-C(23)
1.399(5), C(18)-C(19) 1.347(6), C(19)-C(20) 1.407(7), C(20)-
C(21) 1.352(6), C(21)-C(22) 1.421(5), C(22)-C(23) 1.411(5),
C(23)-C(24) 1.426(5), C(24)-C(25) 1.356(6), C(25)-C(26) 1.407-
(7), C(26)-C(27) 1.355(6), N(1)-Ti(1)-N(2) 104.12(12), N(1)-
Ti(1)-N(3) 104.92(12), N(2)-Ti(1)-N(3) 80.16(12), P(1)-N(1)-
Ti(1) 175.1(2), C(18)-N(2)-C(22) 117.5(3), C(18)-N(2)-Ti(1)
134.7(3), C(22)-N(2)-Ti(1) 105.4(2), C(27)-N(3)-C(23) 117.2-
(3), C(27)-N(3)-Ti(1) 135.5(3), C(23)-N(3)-Ti(1) 105.6(2).
Scheme 2
The above chemistry suggests that 1 reacts as a source of
Ti(II), losing ethylene and undergoing oxidative addition with
alkyl halides to give the products 3-6. This view is supported
by the reaction of 1 with bipyridine, which gives the dark blue
1
crystal product 9 in 61% yield. The H NMR data in toluene-
d8 at -80 °C showed resonances at 7.43, 7.34, 6.37, and 5.35
ppm attributable to the bipyridine ligand and at 6.31 and 1.02
ppm attributable to the Cp and phosphinimide ligands. X-ray
structural data confirmed the formulation of 9 as CpTi(NPt-
Bu3)(bipy) (Figure 2). The Ti-N distance for the phosphinimide
was 1.834(3) Å. As in 5 and many other phosphinimide
derivatives, the geometry at the phosphinimide N was ap-
proximately linear. The bipyridine is approximately planar,
forming an angle of 72.4° with respect to the plane of the
cyclopentadienyl ligand. The C-C bond lengths about the
bipyridyl ligand suggest electron transfer from Ti to the ligand,
similar to that observed for a number of related Ti-bipyridine
complexes.18-24 This view is supported by the distortion from
planar geometry at the N atoms as represented by the C(18)-
N(2)-Ti(1) and C(27)-N(3)-Ti(1) angles of 134.7(3)° and
resonances at 5.99, 5.09, and 4.94 ppm. This was affirmed via
a crystallographic study (Figure 1). The coordination sphere
about Ti is pseudo-tetrahedral with Ti-N, Ti-Br, and Ti-Calkyl
distances of 1.777(4), 2.4512(11), and 2.176(6) Å. The phos-
phinimide ligand is approximately linear at N as expected, and
the remaining metric parameters are unexceptional. A similar
reaction of 1 with allyl chloride led to the formation of the
related product CpTiCl(NPt-Bu3)(CH2CHCH2) (6) in 59% yield
(Scheme 2). Observation of quintet and doublet 1H NMR
resonances at 6.50 and 3.82 ppm suggests an η3-allyl formulation
of 6. Complexes 4 and 6 were readily converted to CpTiMe-
(NPt-Bu3)(CH2Ph) (7) and CpTiMe(NPt-Bu3)(CH2CHCH2) (8),
respectively (Scheme 2). Preliminary X-ray data for 7 were
consistent with this formulation, although again poor crystal
quality precluded a publishable solution.
(16) Torrent, M.; Sola, M.; Frenking, G. Chem. ReV. 2000, 100, 439-
493.
(17) Couty, M.; Hall, M. B. J. Comput. Chem. 1996, 17, 1359-1370.
(18) Carmalt, C. J.; Cowley, A. H.; Culp, R. D.; Jones, R. A.; Sun, Y.-
M.; Fitts, B.; Whaley, S.; Roesky, H. W. Inorg. Chem. 1997, 36, 3108.
(19) Durfee, L. D.; Fanwick, P. E.; Rothwell, I. P.; Folting, K.; Huffmann,
J. C. J. Am. Chem. Soc. 1987, 109, 4720.
(20) Gyepes, R.; Witte, P. T.; Horacek, M.; Cisarova, I.; Mach, K. J.
Organomet. Chem. 1998, 551, 207.
(21) Kempe, R.; Sieler, J.; Ritter, U.; Walther, D. Z. Kristallogr. 1992,
201, 290.
(22) Kingston, J. V.; Sarveswaran, V.; Parkin, S.; Ladipo, F. T.
Organometallics 2003, 22, 136.
(23) Ozerov, O. V.; Brock, C. P.; Carr, S. D.; Ladipo, F. T. Organo-
metallics 2000, 19, 5016.
(24) Thewalt, U.; Berhalter, K. J. Organomet. Chem. 1986, 302, 193.

4784 Organometallics, Vol. 25, No. 20, 2006
Voth et al.
Scheme 3
Figure 3. ORTEP drawing of the cation of 12; 30% thermal
ellipsoids are shown. Hydrogen atoms are omitted for clarity.
Distances (Å) and angles (deg): Ti(1)-N(1) 1.785(2), Ti(1)-C(1)
2.129(3), Ti(1)-Cl(1) 2.3041(11), Si(1)-C(2) 1.905(3), Si(1)-Si-
(2) 2.3337(13), Si(1)-Si(3) 2.3417(13), Si(1)-Si(4) 2.3449(12),
P(1)-N(1) 1.583(2), N(1)-Ti(1)-C(1) 98.64(11), N(1)-Ti(1)-
Cl(1) 106.07(8), C(1)Ti(1)-Cl(1) 97.43(10), P(1)-N(1)-Ti(1)
178.82(15).
1
product 10 in 59% isolated yield. The H NMR data showed
doublet of triplet resonances at 2.30 and 1.47 ppm attributed to
the diastereotopic methylene protons. In addition, a multiplet
at 1.81 ppm and 13C{1H} resonances at 60.6 and 21.1 ppm were
attributed to an ethyl linkage between Ti and Si, resulting in
the formulation of 10 as CpTiCl(NPt-Bu3)(CH2CH2SiPh2Me).
The analogous product CpTiCl(NPt-Bu3)(CH2CH2SiMe3) (11)
was derived from the reaction of 1 with PMe3 and ClSiMe3.
Similar reactions of 1 with PMe3 and ClSi(SiMe3)3, Me3SiOSO2-
CF3, and ClSnn-Bu3 gave CpTiCl(NPt-Bu3)(CH2CH2Si(SiMe3)3)
(12), CpTi(NPt-Bu3)(CH2CH2SiMe3)(OSO2CF3) (13), and Cp-
TiCl(NPt-Bu3)(CH2CH2Snn-Bu3) (14), respectively, all in high
yields (Scheme 3). Compound 12 was characterized by X-ray
crystallography (Figure 3). These data confirmed the presence
of the ethylene linkage between the Ti and Si centers. As
expected, the geometry about Ti in 12 is pseudo-tetrahedral with
Ti-C, Ti-Cl, and Ti-N distances of 2.129(3), 2.3041(11), and
1.785(2) Å, respectively. A similar reaction of 1, PMe3, and
SiCl4 proceeds to give CpTiCl(NPt-Bu3)(CH2CH2SiCl3) (15) in
78% yield (Scheme 3). Interestingly, altering the Ti:Si stoichi-
ometry to 2:1 afforded the dimetallic complex [CpTiCl(NPt-
Bu3)(CH2CH2)]2SiCl2 (16) in 44% isolated yield. It is notewor-
thy that similar reactions with diethylchlorophosphate were
Figure 4. ORTEP drawing of the cation of 19; 30% thermal
ellipsoids are shown. Hydrogen atoms are omitted for clarity. One
orientation of the disordered t-Bu groups are shown. Distances (Å)
and angles (deg): Ti(1)-N(1) 1.777(3), Ti(1)-C(18) 2.131(4), Ti-
(1)-Cl(1) 2.3227(13), Sn(1)-C(19) 2.155(4), P(1)-N(1) 1.595-
(4), N(1)-Ti(1)-C(18) 97.94(14), N(1)-Ti(1)-Cl(1) 105.07(11),
C(18)-Ti(1)-Cl(1) 100.68(12), P(1)-N(1)-Ti(1) 175.0(2).
135.5(3)°. This view is also consistent with the comparatively
short Ti-N distances of 2.044(3) and 2.055(3) Å.
The characterization of compound 1 as a Ti(II) synthon
prompted us to probe reactions with main group halides (Scheme
3). For example reaction of 1 with PMe3 in the presence of
ClSiMePh2 results in the isolation of red-brown crystalline
Figure 5. Reaction profile for reaction of CpTi(NPH3)(CH2CH2CH2CH2) with PH3; [Ti] ) CpTi(NPH3).

Functionalizing Titanium-Phosphinimide Complexes
Organometallics, Vol. 25, No. 20, 2006 4785
Figure 6. Reaction profile for reaction of CpTi(NPH3)(CH2CH2)(PH3) with ClPPh2; [Ti] ) CpTi(NPH3).
Scheme 5
Scheme 4
Cl, and Ti-N distances of 2.131(4), 2.3227(13), and 1.777(3)
Å (Figure 4).
With the apparent results due to steric demands noted, the
syntheses of two- and four-carbon chain derivatives from 1 was
explored. Reaction of 1 in the presence of PMe3 with ClBcat
(cat ) O2C6H4) led to the formation of CpTiCl(NPt-Bu3)(CH2-
CH2Bcat) (20) in 52% yield as a light brown powder (Scheme
4), while reaction of 1 with only ClBcat gave 21. This latter
species was isolated in an overall yield of 62% and formulated
as CpTiCl(NPt-Bu3)(CH2CH2CH2CH2Bcat) (21) (Scheme 4).
The 1H NMR spectrum of 20 showed methylene resonances as
2.35, 1.82, and 1.93, while 21 shows methylene resonances at
2.11, 1.71, 1.95, 1.68, and 1.27 ppm. The 11B{1H} NMR spectra
for 20 and 21 show resonances at 34.6 and 35.4 ppm,
respectively, consistent with the differing formulations. In a
similar manner the compounds CpTiCl(NPt-Bu3)(CH2CH2PPh2)-
(22) and CpTiCl(NPt-Bu3)(CH2CH2CH2CH2PPh2) (23) were
prepared in 70% and 67% yield, respectively, from the reactions
of 1 with ClPPh2 in the presence and absence of PMe3,
respectively (Scheme 4). These complexes show two resonances
in the 31P{1H} NMR spectra at -80 °C attributable to the
phosphinimide and the pendant phosphine fragment. In the case
of 22 the chemical shifts are 39.1 and -8.7 ppm, while for 23
they are 38.1 and -15.2 ppm. In a similar fashion, the analogous
propylene metallacycle 2 reacts with ClPPh2 to give a brown
oil in 47% yield formulated as CpTiCl(NPt-Bu3)(CH2CH-
(CH3)CH(CH3)CH2PPh2) (24).
observed for the zirconocene-ethylene complex Cp2Zr(CH2-
CH2)(PMe3) to give Cp2ZrCl(CH2CH2P(O)(OEt)2).25 As well,
reactions of Cp2Zr(CH2CH2)(PMe3) with group IV halides gave
R3EEt (E ) Si, Ge, Sn; R ) Ph or Bu; X ) Cl, OEt, or OER3)
upon hydrolysis.26
It is interesting and noteworthy that reaction of 1 with SiCl4
in the absence of PMe3 gave the new product 17, which was
isolated in 49% yield. The 1H NMR spectrum reveals methylene
resonances at 2.03, 1.49, 1.76, 1.44, and 1.16 ppm. These and
13C{1H} NMR data were consistent with the formulation of 17
as CpTiCl(NPt-Bu3)(CH2CH2CH2CH2SiCl3) (Scheme 3). In a
similar fashion, direct reaction of 1 with ClSnMe3 afforded the
complex CpTiCl(NPt-Bu3)(CH2CH2CH2CH2SnMe3) (18) in
73% yield as a dark red oil (Scheme 3). While these syntheses
suggest that two- and four-carbon chain derivatives are acces-
sible in a controlled fashion by the presence or absence of PMe3,
it should be noted that steric demands appear to play a role as
well. This is illustrated by the reaction of 1 with ClSnPh3, which
gave the two-carbon chain derivative CpTiCl(NPt-Bu3)(CH2-
CH2SnPh3) (19). X-ray data for 19 confirmed the formulation
with a pseudo-tetrahedral geometry about Ti and Ti-C, Ti-
Compounds 23 and 24 were further derivatized by complex-
ation of the pendant phosphine fragment by Rh. Reaction of
these compounds with [(cod)RhCl]2 afforded CpTiCl(NPt-
Bu3)(CH2CH2CH2CH2PPh2)RhCl(cod) (25) and CpTiCl(NPt-
(25) Xi, C.; Ma, M.; Li, X. Chem. Commun. 2001, 2554-2555.
(26) Ura, Y.; Hara, R.; Takahashi, T. Chem. Lett. 1998, 195-196.

4786 Organometallics, Vol. 25, No. 20, 2006
Voth et al.
Table 1. Crystallographic Parametersa
9
5
12
19
formula
fw
C21H39BrNPTi
464.31
C27H40N3PTi
485.49
C28H63ClNPSi4Ti
640.47
C37H51ClNPSnTi
742.80
cryst syst
space group
a (Å)
b (Å)
c (Å)
orthorhombic
Pbca
14.1420(14)
13.1491(13)
26.373(3)
monoclinic
P21/c
monoclinic
P21/n
orthorhombic
Pna21
24.278(3)
9.6131(11)
16.0617(19)
9.1234(16)
15.276(3)
19.170(3)
98.340(2)
2643.4(8)
4
1.220
0.403
25 055
4634
370
13.990(2)
16.640(3)
17.081(3)
100.728(3)
3906.7(11)
4
1.089
0.468
18 630
5493
â (deg)
V (Å3)
4904.2(8)
8
1.258
2.048
44 568
4309
3748.5(8)
4
1.316
1.017
34 687
6605
Z
d(calc) (g cm-1
)
abs coeff, µ (cm-1
)
no. of data collected
no. of data Fo2 > 3σ(Fo )
2
no. of variables
226
325
379
R
Rw
GOF
0.0569
0.1495
1.058
0.0636
0.1859
0.881
0.0462
0.1263
1.040
0.0319
0.0795
1.048
a The data were collected at 20 °C with Mo KR radiation (λ ) 0.71073 Å).
Bu3)(CH2CH(CH3)CH(CH3)CH2PPh2)RhCl(cod) (26) in 87%
and 44% yield, respectively (Scheme 5). Complexation of the
phosphine fragment by Rh was evidenced in 25 and 26 by the
downfield 31P chemical shifts to 27.8 and 25.0 ppm with Rh-P
coupling constants of 149 and 148 Hz, respectively.
(Figure 6 (C)) and ClPPh2. In this case, ligand exchange was
shown to be a relatively low-energy process that led to
subsequent P-Cl bond cleavage and formation of the Ti-Cl
and C-P bonds, affording the thermodynamically favored
product CpTiCl(NPH3)(CH2CH2PPh2) (Figure 6 (D)). These
results suggest that the ability of the main group elements to
form the transition state in which the main group element
interacts with Cl and the proximal C of ethylene may account
for the formation of the functionalized alkyl chain. Presumably
a similar mechanism occurs for the formation of the related four-
carbon derivatives in the absence of PMe3, although this aspect
was not probed with computations. It is noteworthy that carbon-
based halides reacted differently to afford what can be consid-
ered the products of oxidation addition to a Ti(II) synthon with
loss of 2 equiv of ethylene. This may arise from the ability of
the Si, Sn, P, and B to accommodate interaction with the carbon
atoms of the metallacycle in the four-centered transition state,
thus prompting C-E bond formation.
In conclusion, the phosphinimide-based metallacycles react
as a Ti(II) synthon in reactions with alkyl halides. On the other
hand, reactions with Si, Sn, P, and B halides proceed to give
metal complexes with functionalized alkyl chains. In most cases,
both two- and four-carbon chain products can be accessed by
performing the reaction in the presence or absence of PMe3,
respectively. The utility the resulting functionalized complexes
is now the subject of investigations.
The reactivity of compound 1 with main group halides stands
in contrast to its behavior with alkyl halides. Moreover, the
above synthetic chemistry clearly implies that PMe3 reacts with
1 to alter the course of subsequent reaction with main group
halides. Attempts to explore this reaction in situ by NMR
spectroscopy offered no definitive data. Analogous metallocene
chemistry showed the facile loss of ethylene from Cp2Ti(CH2-
CH2)2 to give Cp2Ti(CH2CH2),27 while the species Cp2Zr(CH2-
CH2)(PMe3) was readily prepared and characterized.28 However,
attempts to either observe or isolate the analogous species CpTi-
(NPt-Bu3)(CH2CH2)(PMe3) were inconclusive and unsuccessive.
DFT computations provided some further insight. In particu-
lar, they revealed that the model five-membered metallacycle
CpTi(NPH3)(CH2CH2CH2CH2) (Figure 5 (A)) in solution was
thermodynamically favored by 19.2 kcal/mol over the mono-
ethylene three-membered metallacycle CpTi(NPH3)(CH2CH2)
(Figure 5 (A)). Computations were also performed to consider
the interaction of PH3 with the model metallacycle. Coordination
of phosphine to Ti provided a low-energy route to loss of
ethylene and the formation of CpTi(NPH3)(CH2CH2)(PH3)
(Figure 5 (C)). These results support the view that loss of
ethylene from the metallacycle 1 via a concerted associative
process is a lower energy pathway than simple ethylene
dissociation. This is consistent with the stability of 1, which
stands in contrast to the related metallocene compound Cp2Ti-
(CH2CH2)2,27 where dissociation of ethylene is facile.
Acknowledgment. Financial support from NSERC of Canada
and NOVA Chemicals Corp. is gratefully acknowledged.
The reaction of the transient phosphine complex with main
group halides was modeled using CpTi(NPH3)(CH2CH2)(PH3)
Supporting Information Available: Crystallographic informa-
tion files (CIF). This material is available free of charge via the
Internet at http://pubs.acs.org.
(27) Cohen, S. A.; Bercaw, J. E. Organometallics 1985, 4, 1006-14.
(28) Alt, H. G.; Denner, C. E.; Thewalt, U.; Rausch, M. D. J. Organomet.
Chem. 1988, 356, C83-C85.
OM060565P