Synthesis, structure, and reactivity of titanium phosphinimide thiolate complexes

Article abstract of DOI:10.1021/om011042e

A series of titanium-phosphinimide thiolate complexes were prepared employing either thiolate for chloride metathesis or protonolysis of metal-carbon bonds by thiols. In these ways the following species were obtained: CpTi(NPR′_s)(SR)₂ (R′ = i-Pr, R = CH₂Ph 3; Ph 4, t-Bu 5, (SR)₂ = S₂(CH₂)2 6, S₂(CH₂)₃ 7, S₂(CH₂)₂C₆H₄ 8; R′ = t-Bu, R = CH₂Ph 9; Ph 10, t-Bu 11); Cp(t-Bu₃PN)TiMe(SPh) 12; and (t-Bu₃PN)₂Ti(SR)₂ (R = CH₂Ph 14; Ph 15, t-Bu 16). Reactions of (t-Bu₃PN)₂TiMe₂ with 1 equiv of HSCH₂Ph gave a cyclometalated species 17, (t-Bu₃PN)₂Ti(η²-SCHPh). The analogous reaction of 1 equiv of phenylthiol generated the species (t-Bu₃PN)₂Ti(Me)(SPh) 18. While 17 and 18 could not be isolated free of 14 and 15, respectively, the analogous reaction of tert-butylthiol afforded (t-Bu₃PN)₂Ti(Me)(St-Bu) 19 cleanly. Attempts to effect sulfur insertion into Ti-Me bonds were undertaken via the reaction of (t-Bu₃PN)₂TiMe₂ with S₈ but gave instead the species (t-Bu₃PN)₂Ti(η²-S₅) 20. The reactivity of the thiolate derivatives, 3-5 with excess AlMe₃, was examined. Spectroscopic and crystallographic studies revealed the formation of (CpTi(μ-SR)(μ-NPi-Pr₃)(C)(AlMe₂)₂-(μ-S R)AlMe (R = CH₂Ph 21, Ph 22, t-Bu 23). Analogous reactions of 7 and 8 with AlMe₃ afforded [Cp(i-Pr₃PN)Ti(SRS)].(AlMe₃)₃ (R = (CH₂)₃ 24, ((CH₂)₂(C₆H₄)) 25). The mechanistic implications of the observed multiple C-H bond activation are considered. Crystallographic studies of 4, 6, 7, 14, 16, and 20-23 are reported.

Full text of DOI:10.1021/om011042e

1646
Organometallics 2002, 21, 1646-1653
Syn th esis, Str u ctu r e, a n d Rea ctivity of Tita n iu m
P h osp h in im id e Th iola te Com p lexes
Chris Ong, J ames Kickham, Steve Clemens, Fred Gue´rin, and
Douglas W. Stephan*
School of Physical Sciences, Chemistry and Biochemistry, University of Windsor, Windsor,
Ontario, Canada N9B 3P4
Received December 6, 2001
A series of titanium-phosphinimide thiolate complexes were prepared employing either
thiolate for chloride metathesis or protonolysis of metal-carbon bonds by thiols. In these
ways the following species were obtained: CpTi(NPR′3)(SR)2 (R′ ) i-Pr, R ) CH2Ph 3; Ph 4,
t-Bu 5, (SR)2 ) S2(CH2)2 6, S2(CH2)3 7, S2(CH2)2C6H4 8; R′ ) t-Bu, R ) CH2Ph 9; Ph 10, t-Bu
11); Cp(t-Bu3PN)TiMe(SPh) 12; and (t-Bu3PN)2Ti(SR)2 (R ) CH2Ph 14; Ph 15, t-Bu 16).
Reactions of (t-Bu3PN)2TiMe2 with 1 equiv of HSCH2Ph gave a cyclometalated species 17,
(t-Bu3PN)2Ti(η2-SCHPh). The analogous reaction of 1 equiv of phenylthiol generated the
species (t-Bu3PN)2Ti(Me)(SPh) 18. While 17 and 18 could not be isolated free of 14 and 15,
respectively, the analogous reaction of tert-butylthiol afforded (t-Bu3PN)2Ti(Me)(St-Bu) 19
cleanly. Attempts to effect sulfur insertion into Ti-Me bonds were undertaken via the
reaction of (t-Bu3PN)2TiMe2 with S8 but gave instead the species (t-Bu3PN)2Ti(η2-S5) 20. The
reactivity of the thiolate derivatives, 3-5 with excess AlMe3, was examined. Spectroscopic
and crystallographic studies revealed the formation of (CpTi(µ-SR)(µ-NPi-Pr3)(C)(AlMe2)2-
(µ-SR)AlMe (R ) CH2Ph 21, Ph 22, t-Bu 23). Analogous reactions of 7 and 8 with AlMe3
afforded [Cp(i-Pr3PN)Ti(SRS)]‚(AlMe3)3 (R ) (CH2)3 24, ((CH2)2(C6H4)) 25). The mechanistic
implications of the observed multiple C-H bond activation are considered. Crystallographic
studies of 4, 6, 7, 14, 16, and 20-23 are reported.
In tr od u ction
(AlMe2)3 and CpTi(µ2-Me)(µ2-NPR3)(µ4-C)(AlMe2)3-
(AlMe3).8,9 In these cases, the central carbide carbon was
found to be four- or five-coordinate. Related C-H bond
activation has been observed in the formation of the
Tebbe reagent, Cp2Ti(µ-CH2)(µ-Cl)AlMe2,10 and in the
clusters [(Cp*MMe)(µ-F)2AlMe2]2 and [(Cp*M)3Al6Me8-
(µ3-CH2)2(µ4-CH)4(µ3-CH)]11,12 and very recently in the
Zr-C aggregates (Cp*Zr)4(µ-Cl)5(Cl)(µ-CH)2 and (Cp*Zr)5-
(µ-Cl)6(µ-CH)3.13 In this article, we describe the synthe-
sis and structures of a series of Ti-phosphinimide-
thiolate complexes. The reactions of such complexes
with AlMe3 are examined, the nature of the resulting
products of C-H bond activation is described, and the
mechanistic implications are considered. A preliminary
account of some of this chemistry has been previously
communicated.14
While much of early metal chemistry is based on
metallocene derivatives, more recently attention has
focused on related monocyclopentadienyl and noncyclo-
pentadienyl analogues, as such systems have proved to
be more reactive, affording novel reactivity. In the case
of Ti-thiolate chemistry, we have observed that com-
plexes of the form CpTi(SR)xCl2-x undergo either â-C-H
or C-S bond activation of the thiolate ligands depending
on reaction conditions.1-5 In developing related systems,
we are exploring ancillary ligands that act as steric
analogues to cyclopentadienyl ligands. In the case of Ti-
phosphinimide complexes, we have uncovered a family
of complexes of the form CpTi(NPR3)X2 and (R3PN)2TiX2
that are effective ethylene polymerization catalysts.6,7
In addition, we have shown that the reactions CpTi-
(NPR3)Me2 with AlMe3 result in unprecedented triple
C-H bond activation of a methyl group, yielding the
Ti-Al-carbide aggregates CpTi(µ2-Me)(µ2-NPR3)(µ4-C)-
Exp er im en ta l Section
Gen er a l Da ta . All preparations were done under an
atmosphere of dry, O2-free N2 employing both Schlenk line
(1) Firth, A. V.; Stephan, D. W. Organometallics 1997, 16, 2183-
2188.
(8) Kickham, J . E.; Guerin, F.; Stewart, J . C.; Stephan, D. W. Angew.
Chem., Int. Ed. 2000, 39, 3263-3266.
(2) Firth, A. V.; Stephan, D. W. Inorg. Chem. 1997, 36, 1260-1262.
(3) Firth, A. V.; Witt, E.; Stephan, D. W. Organometallics 1998, 17,
3716-3722.
(9) Kickham, J . E.; Guerin, F.; Stewart, J . C.; Urbanska, E.; Stephan,
D. W. Organometallics 2001, 20, 1175-1182.
(10) Tebbe, F. N.; Parshall, G. W.; Reddy, G. S. J . Am. Chem. Soc.
1978, 100, 3611-3613.
(4) Huang, Y.; Nadasdi, T. T.; Stephan, D. W. J . Am. Chem. Soc.
1994, 116, 5483-5484.
(11) Herzog, A.; Roesky, H. W.; Zak, Z.; Noltemeyer, M. Angew.
Chem., Int. Ed. Engl. 1994, 33, 967-968.
(5) Huang, Y.; Etkin, N.; Heyn, R. R.; Nadasdi, T. T.; Stephan, D.
W. Organometallics 1996, 15, 2320-2330.
(12) Herzog, A.; Roesky, H. W.; J ager, F.; Steiner, A.; Noltemeyer,
M. Organometallics 1996, 15, 909-917.
(6) Stephan, D. W.; Guerin, F.; Spence, R. E. v. H.; Koch, L.; Gao,
X.; Brown, S. J .; Swabey, J . W.; Wang, Q.; Xu, W.; Zoricak, P.; Harrison,
D. G. Organometallics 1999, 18, 2046-2048.
(13) Yue, N.; Hollink, E.; Guerin, F.; Stephan, D. W. Organometallics
2001, 20, 4424-4433.
(7) Stephan, D. W.; Stewart, J . C.; Guerin, F.; Spence, R. E. v. H.;
Xu, W.; Harrison, D. G. Organometallics 1999, 18, 1116-1118.
(14) Guerin, F.; Stephan, D. W. Angew. Chem., Int. Ed. 1999, 38,
3698-3701.
10.1021/om011042e CCC: $22.00 © 2002 American Chemical Society
Publication on Web 03/21/2002

Titanium Phosphinimide Thiolate Complexes
Organometallics, Vol. 21, No. 8, 2002 1647
techniques and Innovative Technology, M.Braun, or Vacuum
Atmospheres inert atmosphere gloveboxes. Solvents were
purified employing Grubbs’ type column systems manufac-
tured by Innovative Technology. All organic reagents were
purified by conventional methods. 1H and 13C{1H} NMR
spectra were recorded on Bruker Avance-300 and -500 spec-
trometers operating at 300 and 500 MHz, respectively. Trace
(m, 18H, PCHMe2). 31P{1H} NMR: 27.0. 13C{1H} NMR: 110.7,
37.6, 34.7, 26.8 (d, J PC ) 56 Hz), 16.8. Anal. Calcd for C17H32
-
NPS2Ti: C, 51.90; H, 8.20; N, 3.56. Found: C, 51.24; H, 8.25;
1
N, 3.46. 8: method (ii): yield 80%. H NMR (C6D6): 7.32 (m,
2H, C6H4) 7.09 (m, 2H, C6H4), 6.15 (s, 5H, Cp), 5.07 (d, 2J HH
)
2
12 Hz, 2H, SCH2), 4.70 (d, J HH ) 12 Hz, 2H, SCH2), 1.60 (m,
3H, PCHMe2), 0.93 (m, 18H, PCHMe2). 31P{1H} NMR: 28.6.
13C{1H} NMR: 110.6, 39.6, 26.7 (d, J PC ) 56 Hz), 16.7. Anal.
Calcd for C22H34NPS2Ti: C, 58.01; H, 7.52; N, 3.08. Found:
C, 57.62; H, 7.68; N, 2.95. 9: yield 80%. 1H NMR: 7.55 (d,
3J HH ) 7.6 Hz, 4H, o-Ar-H), 7.18 (t, 3J HH ) 7.6 Hz, 4H, m-ArH),
1
amounts of protonated solvents were used as references in H
NMR spectra, and chemical shifts (δ) are reported relative to
SiMe4. 31P{1H} NMR spectra were recorded on a Bruker
Avance-300 and are referenced to 85% H3PO4. All NMR spectra
were recorded in C6D6 unless otherwise noted. Guelph Chemi-
cal Laboratories performed combustion analyses. The com-
pounds CpTi(NPi-Pr3)Cl2 1,7 CpTi(NPi-Pr3)Me2 2,7 CpTi(NPt-
Bu3)Me2 9,7 (t-Bu3PN)2TiMe2 13,6 and CpTi(µ2-Me)(µ2-NPi-
3
7.05 (t, J HH ) 7.6 Hz, 2H, p-ArH), 6.30 (s, 5H, Cp), 4.63 (s,
3
4H, SCH2Ph), 1.18 (d, J PH ) 13 Hz, 27H, PCMe3). 31P{1H}
1
NMR: 40.8. 13C{1H} NMR: 30.1, 41.7 (d, J PC ) 43 Hz), 43.2,
111.9, 26.6, 128.8, 129.4, 145.2. Anal. Calcd for C31H46NPS2-
Ti: C, 64.68; H, 8.05; N, 2.43. Found: C, 64.58; H, 7.95; N,
2.23. 10: method (ii): yield 93%. 1H NMR: 7.98 (d, 3J HH ) 7.6
Pr3)(µ4-C)(AlMe2)3 were prepared via published methods.
15
AlMe3 and the thiols were purchased from Aldrich and Strem
Chemical Companies and used without further purification.
3
Hz, 4H, o-PhH), 7.11 (t, J HH ) 7.6 Hz, 4H, m-PhH), 6.95 (t,
3J HH ) 7.6 Hz, 2H, p-PhH), 6.18 (s, 5H, Cp), 1.11 (d, 3J PH ) 14
Hz, 27H, PCMe3). 31P{1H} NMR: 43.7. 13C{1H} NMR: 29.9,
Syn th esis of Cp Ti(NP i-P r 3)(SR)2 (R ) CH2P h 3; P h 4,
t-Bu 5); [Cp Ti(NP i-P r 3)(S2(CH2)2)]2 6; Cp Ti(NP i-P r 3)(S2R)
(R ) (CH2)3 7, (CH2)2C6H4 8); Cp Ti(NP t-Bu 3)(SR)2 (R )
CH2P h 9, P h 10, t-Bu 11); (t-Bu 3P N)2Ti(SR)2 (R ) CH2P h
14, P h 15, t-Bu 16); a n d (t-Bu 3P N)2Ti(Me)(St-Bu ) 19. These
complexes were prepared employing one of two methods using
the appropriate thiol or alkyl-thiolate reagent. One represen-
tative preparation of each method is presented. (i) To a THF
solution (10 mL) of 1 (0.250 g; 0.698 mmol) was added solid
LiSCH2Ph (0.200 g; 1.550 mmol) at room temperature. The
yellow solution turned dark red within 30 min and was stirred
for 12 h. The solvent was removed under vacuum, the solid
extracted with benzene (3 × 10 mL), and the solution filtered
through Celite. The volume of the solution was reduced to 5
mL. A red microcrystalline solid was formed upon addition of
20 mL of hexanes. Red solid 3 (0.280 g; 0.525 mmol) was
isolated by filtration and dried under vacuum in 75% yield.
(ii) To a solution of 2 (0.056 g; 0.156 mmol) in benzene was
added HSt-Bu (0.028 g; 0.312 mmol). The solution was allowed
to stir for 12 h and the solvent removed under vacuum to afford
5 as a yellow powder in 83% yield. 3: method (i): yield 65%.
1H NMR: 7.57 (m, 4H, SCH2Ph), 7.20 (m, 4H, SCH2Ph), 7.06
1
41.8 (d, J PC ) 43 Hz), 113.3, 125.0, 128.7, 133.6, 147.7. Anal.
Calcd for C29H42NPS2Ti: C, 63.60; H, 7.73; N, 2.56. Found:
C, 63.55; H, 7.22; N, 2.21. 11 method (ii): yield 87%. 1H
3
NMR: 6.49 (s, 5H, Cp), 1.73 (s, 18H, SCMe3), 1.28 (d, J PH
)
13 Hz, 27H, PCMe3). 31P{1H} NMR: 39.9. 13C{1H} NMR:
1
110.5, 46.6, 41.8 (d, J PC ) 43 Hz), 36.5, 30.1. Anal. Calcd for
C
26H36NPS2Ti: C, 59.15; H, 9.93; N, 2.76. Found: C, 58.88;
H, 9.65; N, 2.63. 14: method (ii): yield 95%. 1H NMR: 7.70
3
3
(d, J HH ) 7.3 Hz, 4H, o-SCH2Ph); 7.19 (pseudo t, J HH ) 7.3
3
Hz, 4H, m-SCH2Ph); 7.11 (t, J HH ) 7.3 Hz, 2H, p-SCH2Ph);
4.96 (s, 4H, SCH2); 1.35 (d, J PH ) 12.7 Hz, 54H, PCMe3). 31P-
3
{1H} NMR: 33.4. 13C{1H} NMR: 145.3 (s, ipso-Ph); 129.2 (s,
1
o-Ph); 128.3 (s, m-Ph); 125.9 (s, p-Ph); 40.9 (d, J PC ) 47 Hz,
PCMe3); 37.1 (s, SCH2); 29.9 (s, PCMe3). Anal. Calcd for
C
38H64N2P2S2Ti: C, 62.79; H, 9.43; N, 3.85. Found: C, 62.51;
H, 9.19; N, 3.76. 15: method (ii): yield 90%. 1H NMR: 8.21
3
3
(d, J HH ) 7.1 Hz, 4H, o-SPh); 7.21 (pseudo t, J HH ) 7.5 Hz,
3
3
2H, p-SPh); 7.11 (t, J HH ) 7.8 Hz, 4H, m-SPh); 1.23 (d, J PH
) 13.0 Hz, 54H, PCMe3). 31P{1H} NMR: 34.8. 13C{1H} NMR:
144.8 (s, ipso-Ph); 143.2 (s, o-Ph); 133.8 (s, m-Ph); 123.8 (s,
1
2
p-Ph); 40.8 (d, J PC ) 38.4 Hz, PCMe3); 29.7 (s, PCMe3). Anal.
(m, 1H, SCH2Ph), 6.27 (s, 5H, Cp), 4.75 (d, J HH ) 13 Hz, 2H,
2
2
Calcd for C36H64N2P2S2Ti: C, 61.87; H, 9.23; N, 4.01. Found:
SCH2), 4.65 (d, J HH ) 13 Hz, 2H, SCH2), 1.62 (d of sept, J PH
C, 62.10; H, 9.43; N, 3.72. 16: method (ii): yield 90%. 1H
3
3
3
) 11 Hz, J HH ) 7 Hz, PCHMe2), 0.91 (dd, J PH ) 15 Hz, J HH
NMR: 1.97 (s, 18H, SCMe3); 1.43 (d, 54H, PCMe3). 31P{1H}
) 7 Hz 18H, PCHMe2). 31P{1H} NMR: 31.6. 13C{1H} NMR:
NMR: 31.7. 13C{1H} NMR: 45.3 (s, SCMe3); 41.5 (d, J PC
)
1
1
144.9, 129.0, 126.1, 110.9, 43.4, 26.1 (d, J PC ) 56 Hz,
46.1 Hz, PCMe3); 37.9 (s, SCMe3); 30.3 (s, PCMe3). Anal. Calcd
for C32H72N2P2S2Ti: C, 58.33; H, 11.01; N, 4.25. Found: C,
58.61; H, 10.74; N, 4.50. 19: method (ii): yield 89%. 1H NMR:
PCHMe2), 16.8. Anal. Calcd for C28H40NPS2Ti: C, 63.03; H,
7.56; N: 2.62. Found: C, 62.78; H, 7.24; N, 2.33. 4: method
(i): yield 68%; (ii): yield 61%. 1H NMR: 8.04 (d, 4H, SPh),
7.13 (t, 4H, SPh), 6.97 (t, 2H, SPh), 6.16 (s, 5H, Cp), 1.50 (d of
3
1.94 (s, 9H, SCMe3); 1.39 (d, J PH ) 12.8 Hz, 54H, PCMe3);
1.06 (s, 3H, TiMe). 31P{1H} NMR: 29.2. 13C{1H} NMR: 45.0
2
3
3
d, J PH ) 11.6 Hz, J HH ) 7 Hz, 3H, PCHMe2), 0.81 (dd, J PH
1
) 15 Hz, J HH ) 7 Hz, 18H, PCHMe2). 31P{1H} NMR: 34.9.
3
(s, SCMe3); 41.1 (d, J PC ) 47 Hz, PCMe3); 38.0 (s, SCMe3);
13C{1H} NMR: 147.7, 133.1, 124.3, 112.0, 25.8 (d, J PC ) 55
1
37.8 (s, TiCH3); 30.1 (s, PCMe3). Anal. Calcd for C29H66N2P2-
STi: C, 59.57; H, 11.38; N, 4.79. Found: C, 59.24; H, 11.32;
N, 4.85.
Hz), 16.7. Anal. Calcd for C26H36NPS2Ti: C, 61.77; H, 7.18; N,
2.77. Found: C, 61.58; H, 7.25; N, 2.83. 5: method (ii): yield
83%. 1H NMR: 6.36 (s, 5H, Cp), 1.82 (s, 18H, SCMe3), 1.24
Gen er a tion of (t-Bu 3P N)2Ti-(η2SCHP h ) 17. A resealable
NMR tube equipped with a Teflon screw-cap was charged with
13 (0.022 g, 43 µmol) and C6D6 (0.6 mL). Benzylthiol was added
to the NMR tube, which was immediately sealed. This method
consistently gave a mixture of starting material 13, 14, and
17 and thus could not be isolated analytically pure. 17 was
generated in 60% yield as judged by NMR spectroscopy. 1H
NMR: 7.89 (d, 3J HH ) 4.6 Hz, 2H, o-SPh); 7.25 (pseudo t, 3J HH
) 4.6 Hz, 1H, p-SPh); 6.92 (d, 3J HH ) 4.6 Hz, 2H, m-SPh); 4.85
(s, 1H, TiSCHPh); 1.35 (obscured, 54H, PCMe3). 31P{1H}
NMR: 26.6, 27.9 (2 s, NP syn and anti to Ph). 13C{APT}
NMR: 152.9 (s, ipso-Ph), 126.9 (s, o-Ph); 124.4 (s, p-Ph); 121.0
(s, m-Ph); 88.0 (s, TiSCHPh); 41.05 (d, 1J PC ) 47 Hz, PCMe)3);
30.6 (s, PCMe3).
(m, 2J PH ) 15 Hz, 3J HH ) 7 Hz, 3H, PCHMe2), 0.96 (dd, 3J PH
)
3
14 Hz, J HH ) 8 Hz, 18H, PCHMe2). 31P{1H} NMR: 29.3. 13C-
1
{1H} NMR: 110.7, 36.3, 26.5 (d, J PC ) 56 Hz), 17.1. Anal.
Calcd for C26H36NPS2Ti: C, 56.75; H, 9.53; N, 3.01. Found:
C, 56.38; H, 9.25; N, 2.86. 6: method (ii): yield 93%. 1H
NMR: 6.34 (s, 5H, Cp), 4.61 (t, 3J HH ) 15 Hz, 4H, SCH2), 4.02
3
(t, J HH ) 15 Hz, 4H, SCH2), 1.74 (m, 3H, PCHMe2), 1.04 (m,
18, PCHMe2). 31P{1H} NMR: 30.2. 13C{1H} NMR: 111.8, 33.6,
31.5, 24.3 (d, 1J PC ) 54 Hz,), 15.8. Anal. Calcd for C32H60N2P2S4-
Ti2: C, 50.65; H, 7.97; N, 3.69. Found: C, 50.21; H, 7.81; N,
3.60. 7: method (ii): yield 87%. 1H NMR: 6.31 (s, 5H, Cp),
2
2
3.86 (t, J HH ) 13.0 Hz, 2H, SCH2), 3.51 (t, J HH ) 13.0 Hz,
2H, SCH2), 1.61 (m, 3H, PCHMe2), 0.97 (m, 2H, CH2), 0.85
Gen er ation of CpTi(NP t-Bu 3)Me(SP h ) 12; (t-Bu 3P N)2Ti-
(Me)(SP h ) 18. These complexes were prepared employing
similar methods; thus one representative preparation is
(15) Kickham, J . E.; Guerin, F.; Stewart, J . C.; Urbanska, E.; Ong,
C. M.; Stephan, D. W. Organometallics 2001, 20, 3209.

1648 Organometallics, Vol. 21, No. 8, 2002
Ong et al.
presented. Method (ii) described above was employed. How-
ever, this method consistently gave a mixture of starting
material, 15, and 18, and thus 18 could not be isolated
analytically pure. Compound 18 was generated in 81% yield
as judged by NMR spectroscopy. 12: method (ii): yield 85%.
similar manner, and thus one representative preparation is
detailed. To a solution of 7 (029 g; 0.073 mmol) in benzene
was added 2.0 M AlMe3 (0.11 mL; 0.221 mmol). The solution
was allowed to stir for 12 h and the solvent removed under
vacuum to afford 24 as a dark orange powder. 24: Yield: 78%.
1H NMR: 6.43 (s, 5H, Cp), 3.50 (m, 2H, SCH2), 3.26 (m, 2H,
SCH2) 2.97 (m, 2H, CH2), 1.53 (m, 3H, PCHMe2), 0.76 (m, 18H,
PCHMe2), -0.11 (s, 27H, AlMe). 31P{1H} NMR: 40.8. 13C{1H}
NMR: 118.7, 40.7, 35.3, 30.5 (d, J PC ) 52.5 Hz), 21.1, 20.7.
Anal. Calcd for C26H59Al3NPS2Ti: C, 51.22; H, 9.75; N, 2.30.
3
3
1H NMR: 7.61 (d, J HH ) 7 Hz, 2H, o-PhH), 7.10 (t, J HH ) 7
3
Hz, 2H, m-PhH), 6.96 (t, J HH ) 7 Hz, 1H, p-PhH), 6.06 (s,
5H, Cp), 1.21(d, 3J PH ) 13 Hz, 27H, PCMe3), 1.07 (s, 3H, TiMe).
31P{1H} NMR: 37.5. 13C{1H} NMR: 147.1, 128.6, 124.8, 113.5,
1
112.0, 41.8 (d, J PC ) 43 Hz), 39.7, 30.0. 18: 1H NMR: 7.93
3
3
1
(d, J HH ) 6.8 Hz, 2H, o-SPh); 7.09 (pseudo t, J HH ) 7.7 Hz,
Found: C, 51.01; H, 9.46; N, 2.02. 25: Yield: 55%. H NMR:
3
3
2H, m-SPh); 6.93 (t, J HH ) 6.8 Hz, 1H, p-SPh); 1.29 (d, J PH
) 12.8 Hz, 54H, PCMe3); 1.19 (s, 3H, TiMe), 0.14 (s, CH4). 31P-
{1H} NMR: 29.8. 13C{1H} NMR: 144.6 (s, ipso-Ph); 133.9 (s,
o-Ph); 128.2 (s, m-Ph); 123.6 (s, p-Ph); 40.9 (d, 1J PC ) 46.9 Hz,
PCMe3); 37.4 (s, TiMe); 29.8 (s, PCMe3).
7.42 (m, 2H, C6H4), 7.01 (m, 2H, C6H4), 6.27 (s, 5H, Cp), 4.55
(m, 4H, SCH2), 1.55 (m, 3H, PCHMe2), 0.83 (m, 18H, PCHMe2),
-0.14 (s, 27H, AlMe). 31P{1H} NMR: 41.3. 13C{1H} NMR:
137.5, 130.0, 128.6, 113.9, 25.9 (d, J PC ) 55 Hz), 16.6, 12.8.
Anal. Calcd for C31H61Al3NPS2Ti: C, 55.43; H, 9.15; N, 2.09.
Found: C, 54.96; H, 9.06; N, 2.05.
Syn th esis of (t-Bu 3P N)2Ti(η2-S5) 20. A sintered glass vial
was charged with 13 (0.028 g, 55 µmol), and toluene (6 mL)
was added. Addition of S8 (0.022 g, 86 µmol) resulted in the
immediate formation of a bright yellow solution that was
stirred overnight. The toluene was removed in vacuo, yielding
X-r a y Da ta Collection a n d Red u ction . The crystals were
manipulated 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. The data were collected for a
hemisphere of data in 1329 frames with 10-s exposure times.
Crystal data are summarized in Table 1. The observed
extinctions were consistent with the space groups in each case.
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. An empirical absorption
correction based on redundant data was applied to each data
set. Subsequent solution and refinement was performed using
the SHELXTL solution package. For 16 and 22, which crystal-
lize in noncentrosymmetric space groups, the absolute con-
figurations were obtained by comparison with the inverted
model. In these cases the respective Flack parameters of
0.0720 and -0.0173 were consistent with the correct absolute
configuration.
St r u ct u r e Solu t ion a n d R efin em en t . Non-hydrogen
atomic scattering factors were taken from the literature
tabulations.16 The heavy atom positions were determined using
direct methods. 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 w(Fo - Fc)2,
where the weight w is defined as 4Fo2/2σ(Fo2) 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. Carbon-bound
hydrogen 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. Hydrogen atom temperature factors were
fixed at 1.10 times the isotropic temperature factor of the
carbon atom to which they are bonded. The hydrogen atom
contributions were calculated, but not refined. The final values
of refinement parameters are given in Table 1. Positional
parameters, hydrogen atom parameters, thermal parameters,
and bond distances and angles have been deposited as Sup-
porting Information.
1
3
a yellow powder. Yield: 0.030 g, 85%. H NMR: 1.29 (d, J PH
) 12.9 Hz, 54H, PCMe3). 31P{1H} NMR: 33.2. 13C{1H} NMR:
41.2 (d, J PC ) 46.1 Hz, PCMe3); 29.9 (s, PCMe3). Anal. Calcd
1
for C24H54N2P2S5Ti: C, 44.98; H, 8.49; N, 4.37. Found: C,
44.88; H, 8.44; N, 4.33.
Syn th esis of [Cp Ti(µ2-SR)(µ2-NP i-P r 3)(µ4-C)(AlMe2)2(µ-
SR)AlMe] (R ) CH2P h 21, P h 22, t-Bu 23). These com-
pounds were prepared in a similar manner, and thus one
representative preparation is detailed. To a solution of 4 (0.200
g; 0.396 mmol) in benzene was added 2.0 M AlMe3 (0.75 mL;
1.500 mmol). The solution was stirred for 10 h and the solvent
removed under vacuum. Recrystallization of the product from
benzene afforded 23 as red crystals. 21: Yield: 74%. 1H NMR:
7.27 (d, 4H, SCH2Ph), 7.13 (t, 4H, SCH2Ph), 7.03 (t, 2H,
2
SCH2Ph), 6.26 (s, 5H, Cp), 3.85 (d, J HH ) 13 Hz, 2H, SCH2-
2
2
Ph), 3.75 (d, J HH ) 13 Hz, 2H, SCH2Ph), 1.64 (d of sept, J PH
3
3
) 13 Hz, J HH ) 7 Hz, 3H, PCHMe2), 0.74 (dd, J PH ) 15 Hz,
3J HH ) 7 Hz, 9H, PCHMe2), 0.57 (dd, J PH ) 15 Hz, J HH ) 7
Hz, 9H, PCHMe2), 0.27 (s, 3H, AlMe), 0.11 (s, 3H, AlMe), -0.01
(s, 3H, AlMe), -0.07 (s, 3H, AlMe), -0.29 (s, 3H, AlMe). 31P-
{1H} NMR: 52.9. 13C{1H} NMR: 141.2, 129.0, 129.0, 127.0,
3
3
1
126.8, 110.1, 38.3, 32.6, 26.5 (d, J PC ) 56.4, PCHMe2), 16.4
(d, 2J PC ) 34 Hz, PCHMe2), 14.3, -4.8, -6.9, -7.2, -7.8. Anal.
Calcd for C34H55Al3NPS2Ti: C, 58.19; H, 7.90; N, 2.00. Found:
C, 58.02; H, 761; N, 1.89. 22: Yield: 83%. HNMR: 7.58 (d,
1
2H, SPh), 7.55 (d, 2H, SPh), 7.05 (m, 4H, SPh), 6.95(m, 2H,
2
3
SPh), 6.18 (s, 5H, Cp), 1.80 (d of sept, J PH ) 13 Hz, J HH ) 7
3
3
Hz, 3H, PCHMe2), 0.88 (dd, J PH ) 14 Hz, J HH ) 7 Hz, 9H,
3
3
PCHMe2), 0.85 (dd, J PH ) 14 Hz, J HH ) 7 Hz, 9H, PCHMe2),
0.30 (s, 3H, AlMe), 0.17 (s, 3H, AlMe), 0.06 (s, 3H, AlMe), 0.04
(s, 3H, AlMe), -0.32 (s, 3H, AlMe). 31P{1H} NMR: 54.1. 13C-
{1H} NMR: 140.0, 133.8, 132.8, 131.7, 126.5, 126.1, 111.3, 26.7
1
(d, J PC ) 56.4, PCHMe2), 16.7, -4.4, -5.8, -7.1. Anal. Calcd
for C32H51Al3NPS2Ti: C, 57.05; H, 7.63; N, 2.08. Found: C,
57.16; H, 7.71; N, 2.10. 23: Yield: 56%. 1H NMR: 6.42 (s, 5H,
2
Cp), 1.78 (sept, J PH ) 6 Hz, 3H, PCHMe2), 0.82 (m, 18H,
PCHMe2), 0.29 (m, 9H, AlMe) 0.04 (m, 9H, AlMe), -0.16 (s,
3H, AlMe), -0.28 (m, 6H, AlMe), -0.32 (m, 6H, AlMe). 31P-
{1H} NMR: 51.2. 13C{1H} NMR: 109.5, 35.5 (d, 1J PC ) 10 Hz),
Resu lts a n d Discu ssion
2
30.4, 27.4, 26.6, 17.1 (d, J PC ) 14 Hz), 1.6. Anal. Calcd for
Syn th esis a n d Str u ctu r e. Formation of a series of
titanium-phosphinimide thiolate complexes was
achieved employing two standard synthetic strategies
involving thiolate for chloride metathesis and proto-
nolysis of metal-carbon bonds by thiols (Scheme 1). For
example, reaction of CpTi(NPi-Pr3)Cl2 1 with the lithium
salts LiSR (R ) CH2Ph; Ph) resulted in the formation
C
31H62Al3NPS2Ti: C, 53.07; H, 9.38; N, 2.21. Found: C, 53.49;
H, 9.26; N, 2.06.
Alter n a te Syn th esis of 23. To a solution of CpTi(µ2-Me)-
(µ2-NPi-Pr3)(µ4-C)(AlMe2)3 (0.048 g; 0.099 mmol) in benzene
was added t-BuSH (0.018 g; 0.20 mmol). The reaction was
allowed to stir for 10 h and the solvent removed under vacuum.
Recrystallization of the product from benzene afforded 22 as
burgundy crystals in 60% yield.
Syn th esis of [Cp Ti(NP i-P r 3)(S2R)]‚(AlMe3)3 (R ) (CH2)3
24, (CH 2)2C6H 4 25). These compounds were prepared in a
(16) Cromer, D. T.; Mann, J . B. Acta Crystallogr. A 1968, A24, 321-
324.

Titanium Phosphinimide Thiolate Complexes
Organometallics, Vol. 21, No. 8, 2002 1649
of the species CpTi(NPi-Pr3)(SR)2 (R ) CH2Ph 3; Ph 4).
These products could also be obtained by reactions of
CpTi(NPi-Pr3)Me2 2 with the corresponding thiol with
liberation of methane. In this way, species 3, 4, and
CpTi(NPi-Pr3)(St-Bu)2 5 were prepared. In a similar
manner, protonolysis of 2 by dithiols yielded products
that exhibited spectroscopic parameters consistent with
the empirical formula CpTi(NPi-Pr3)(S2R) (R ) (CH2)2
6, (CH2)3 7, (CH2)2C6H4 8). Similarly, employing the
precursor CpTi(NPt-Bu3)Me2 9, the species CpTi(NPt-
Bu3)(SR)2 (R ) CH2Ph 9; Ph 10; t-Bu 11) were isolated.
Employing the species (t-Bu3PN)2TiMe2 13, the species
(t-Bu3PN)2Ti(SR)2 (R ) CH2Ph 14; Ph 15; t-Bu 16) were
prepared.
While the spectroscopic and elemental analysis data
were consistent with the formulation of these products,
the structures of these molecules were confirmed by
X-ray crystallography in several cases. The structure
of compound 4 (Figure 1) revealed the Ti-N distance
of 1.770(3) Å, slightly longer than the 1.753(3) Å found
for the dichloride precursor 1. The P-N-Ti angle of
166.0(3)° approaches linearity, as is typical of most Ti-
phosphinimide complexes. The average Ti-S bond
distance was found to be 2.395(15) Å, while the S(1)-
Ti-S(2) average bonding angle was determined to be
105.30(6)°. These values compare with the average Ti-S
bond distances of 2.315 Å and the S(1)-Ti-S(2) angle
of 107.6(2)° found for the Ti-aryloxide complex Cp(OAr′)-
Ti(SEt)2.1
An X-ray crystallographic study of 6 revealed a
centrosymmetric dimeric formulation in which two
pseudo-tetrahedral titanium centers are linked by two
dithiolate fragments (Figure 2). The resulting macro-
cycle adopts a crown-like conformation with axial phos-
phinimide ligands on either end. The average Ti-N and
Ti-S bond distances in 6 are 1.790(4) and 2.370(16) Å,
respectively, while the P-N-Ti and S(1)-Ti-S(2)
angles are 162.4(3)° and 109.06(6)°, respectively. This
geometry stands in contrast to related metallocenes of
the form [Cp2M(SCH2CH2S)]n (M ) Ti, Zr, V), in which
an additional metal-sulfur interaction gives rise to
twisted-bridging conformations which dynamically in-
terconvert in solution.17,18 Variable-temperature studies
of 6 showed no temperature dependence of the NMR
resonances. This observation suggests that despite the
fact that chemical evidence suggests that the CpTi-
(NPR3) fragment is more electrophilic than Cp2Ti, a
twisted-conformation of 6 is precluded, as such a
geometry would bring the sterically demanding phos-
phinimide ligands in close proximity to the opposite
cyclopentadienyl ligand.
In contrast to 6, an X-ray crystallographic study of 7
revealed it to be a monometallic, pseudo-tetrahedral Ti
complex (Figure 3) The average Ti-N and Ti-S dis-
tances in 7 are 1.854(5) and 2.40(2) Å, respectively. This
Ti-N distance is slightly longer than that seen in 6,
although the reasons for this remain unclear. The Ti-S
distances are also slightly longer than those seen in the
Ti-aryloxide thiolate species Cp(OAr′)Ti(S2(CH2)3) (Ti-
Sav) value of 2.357(4) Å.19 This suggests the phosphin-
(17) Huang, Y.; Drake, R. J .; Stephan, D. W. Inorg. Chem. 1993,
32, 3022-3028.
(18) Stephan, D. W. J . Chem. Soc., Chem. Commun. 1991, 129-
131.
(19) Firth, A. V.; Stephan, D. W. Inorg. Chem. 1998, 37, 4726-4731.

1650 Organometallics, Vol. 21, No. 8, 2002
Ong et al.
F igu r e 1. ORTEP drawing of 4; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Distances in Å, angles in deg: Ti(1)-N(1) 1.770(3), Ti(1)-
S(2) 2.3903(14), Ti(1)-S(1) 2.4008(14), P(1)-N(1) 1.614-
(3), S(1)-C(15) 1.767(5), S(2)-C(21) 1.775(4), N(1)-Ti(1)-
S(2) 95.88(12), N(1)-Ti(1)-S(1) 106.76(12), S(2)-Ti(1)-
S(1) 105.28(5), P(1)-N(1)-Ti(1) 166.0(3), C(15)-S(1)-Ti(1)
112.36(16), C(21)-S(2)-Ti(1) 110.93(15).
F igu r e 3. ORTEP drawing of one of the two molecules of
7 in the asymmetric unit; 30% thermal ellipsoids are
shown. Hydrogen atoms have been omitted for clarity.
Distances in Å, angles in deg: Ti(1)-N(1) 1.843(5), Ti(1)-
S(2) 2.392(2), Ti(1)-S(1) 2.415(2), S(1)-C(15) 1.893(8),
S(2)-C(17) 1.889(9), P(1)-N(1) 1.631(5), N(1)-Ti(1)-S(2)
104.02(15), N(1)-Ti(1)-S(1) 104.58(17), S(2)-Ti(1)-S(1)
98.62(10), C(15)-S(1)-Ti(1) 98.8(3), C(17)-S(2)-Ti(1) 99.7-
(3), P(1)-N(1)-Ti(1) 168.1(3). Distances and angles in
second molecule in the asymmetric unit: Ti(2)-N(2) 1.830-
(6), Ti(2)-S(4) 2.4067(19), Ti(2)-S(3) 2.410(2), S(3)-C(32)
1.878(7), S(4)-C(34) 1.877(7), P(2)-N(2) 1.647(6), N(2)-
Ti(2)-S(4) 103.67(18), N(2)-Ti(2)-S(3) 104.54(16), S(4)-
Ti(2)-S(3) 97.32(8), C(32)-S(3)-Ti(2) 100.1(2), C(34)-
S(4)-Ti(2) 98.7(2), P(2)-N(2)-Ti(2) 167.8(3).
Sch em e 1
F igu r e 4. ORTEP drawing of 14; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Distances in Å, angles in deg: Ti(1)-N(1) 1.801(4), Ti(1)-
N(2) 1.804(4), Ti(1)-S(1) 2.3596(18), Ti(1)-S(2) 2.3628(17),
S(1)-C(25) 1.835(7), S(2)-C(32) 1.826(7), P(1)-N(1) 1.581-
(4), P(2)-N(2) 1.577(4), N(1)-Ti(1)-N(2) 118.7(2), N(1)-
Ti(1)-S(1) 111.76(15), N(2)-Ti(1)-S(1) 102.44(16), N(1)-
Ti(1)-S(2) 101.48(15), N(2)-Ti(1)-S(2) 114.68(16), S(1)-
Ti(1)-S(2) 107.62(7), C(25)-S(1)-Ti(1) 103.8(3), C(32)-
S(2)-Ti(1) 104.9(2), P(1)-N(1)-Ti(1) 175.8(3), P(2)-N(2)-
Ti(1) 175.5(3).
Ti, comprised of two phosphinimide and two thiolate
ligands. The Ti-N distances vary from 1.801(4) to 1.813-
(4) Å, slightly shorter than those seen in 4, 6, and 7.
Similarly the Ti-S distances range from 2.332(3) to
2.389(3) Å, consistent with the electron-deficient metal
centers in 14 and 16. The remaining metric parameters
are unexceptional. In the case of 14, the phenyl rings
of the benzyl groups adopt a parallel arrangement,
suggestive of π-stacking.
Reactions of 9 with 1 equiv of phenylthiol proceeds
to generate an inseparable mixture of CpTi(NPt-Bu3)-
Me(SPh) 12 and 10. In an similar reaction of 13 with 1
equiv of benzylthiol, a mixture of the products 14 and
a new species presumed to be (t-Bu3PN)2Ti(Me)(SCH2-
Ph) was observed spectroscopically. This latter species
exhibits a 31P{1H} NMR resonance at 29.4 ppm. This
F igu r e 2. ORTEP drawing of 6; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Distances in Å, angles in deg: Ti(1)-N(1) 1.791(2), Ti(1)-
S(1) 2.3701(8), Ti(1)-S(2) 2.3743(8), S(1)-C(15) 1.827(3),
S(2)-C(16) 1.829(3), P(1)-N(1) 1.594(2), N(1)-Ti(1)-S(1)
104.00(8), N(1)-Ti(1)-S(2) 101.94(7), S(1)-Ti(1)-S(2)
109.02(3), C(15)-S(1)-Ti(1) 104.86(9), C(16)-S(2)-Ti(1)
104.68(9), P(1)-N(1)-Ti(1) 162.47(15).
imide ligand is a better donor than aryloxide. The S(1)-
Ti-S(2) angle in 7 is 98.62(10)°, which is smaller than
that reported for 6, presumably a result of chelation.
The solid-state structures of 14 (Figure 4) and 16
(Figure 5) reveal pseudo-tetrahedral geometries about

Titanium Phosphinimide Thiolate Complexes
Organometallics, Vol. 21, No. 8, 2002 1651
F igu r e 7. ORTEP drawing of 21; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Distances in Å, angles in deg: Ti(1)-C(29) 1.900(3), Ti-
(1)-N(1) 2.005(2), Ti(1)-S(2) 2.4588(10), Al(1)-N(1) 1.883-
(2), Al(1)-C(30) 1.953(3), Al(1)-C(29) 2.002(3), Al(1)-S(1)
2.3599(12), Al(2)-C(31) 1.955(4), Al(2)-C(32) 1.969(4), Al-
(2)-C(29) 1.991(3), Al(2)-S(1) 2.4564(13), Al(3)-C(33)
1.962(3), Al(3)-C(34) 1.963(3), Al(3)-C(29) 2.001(3), Al-
(3)-S(2) 2.4103(12), P(1)-N(1) 1.604(2), C(29)-Ti(1)-N(1)
92.82(10), C(29)-Ti(1)-S(2) 93.17(8), N(1)-Ti(1)-S(2)
104.53(6), N(1)-Al(1)-C(30) 119.66(13), N(1)-Al(1)-C(29)
93.41(10), C(30)-Al(1)-C(29) 126.68(13), N(1)-Al(1)-S(1)
113.31(7), C(30)-Al(1)-S(1) 109.79(11), C(29)-Al(1)-S(1)
90.20(8), C(31)-Al(2)-C(32) 113.8(2), C(31)-Al(2)-C(29)
120.1(2), C(32)-Al(2)-C(29) 115.43(14), C(31)-Al(2)-S(1)
106.75(14), C(32)-Al(2)-S(1) 108.54(13), C(29)-Al(2)-S(1)
87.73(8), C(33)-Al(3)-C(34) 116.0(2), C(33)-Al(3)-C(29)
114.80(13), C(34)-Al(3)-C(29) 115.88(13), C(33)-Al(3)-
S(2) 103.96(12), C(34)-Al(3)-S(2) 110.46(12), C(29)-Al-
(3)-S(2) 92.14(8), C(15)-S(1)-Al(1) 110.51(14), C(15)-
S(1)-Al(2) 110.80(13), Al(1)-S(1)-Al(2) 75.15(4), C(22)-
S(2)-Al(3) 112.82(13), C(22)-S(2)-Ti(1) 117.02(11), Al(3)-
S(2)-Ti(1) 73.55(3), P(1)-N(1)-Al(1) 131.25(13), P(1)-
N(1)-Ti(1) 141.24(13), Al(1)-N(1)-Ti(1) 87.07(9), Ti(1)-
C(29)-Al(2) 141.36(14), Ti(1)-C(29)-Al(3) 96.68(12), Al(2)-
C(29)-Al(3) 114.10(13), Ti(1)-C(29)-Al(1) 86.69(10), Al(2)-
C(29)-Al(1) 94.75(11), Al(3)-C(29)-Al(1) 123.08(13).
F igu r e 5. ORTEP drawing of 16; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Distances in Å, angles in deg: Ti(1)-N(1) 1.804(6), Ti(1)-
N(2) 1.813(5), Ti(1)-S(1) 2.332(3), Ti(1)-S(2) 2.389(3),
S(1)-C(28) 1.803(7), S(2)-C(32) 1.781(9), P(1)-N(1) 1.592-
(7), P(2)-N(2) 1.590(6), N(1)-Ti(1)-N(2) 118.2(3), N(1)-
Ti(1)-S(1) 117.4(2), N(2)-Ti(1)-S(1) 98.62(19), N(1)-
Ti(1)-S(2) 90.3(2),N(2)-Ti(1)-S(2) 118.9(2), S(1)-Ti(1)-
S(2) 115.06(16), C(28)-S(1)-Ti(1) 121.2(3), C(32)-S(2)-
Ti(1) 118.7(4), P(1)-N(1)-Ti(1) 171.7(4), P(2)-N(2)-Ti(1)
172.1(4).
spectrum reveals the methine carbon resonance at 88.0
ppm. A two-dimensional HMQC C-H correlation spec-
trum confirms the connectivity of these resonances.
Despite the fact that 17 could be characterized in
solution, all efforts to isolate it from 14 and residual 13
were unsuccessful, and thus analytical data for 17 were
not obtained. It is noteworthy that we have previously
shown that the thermal reaction of Cp(OAr′)TiMe(SEt)
affords the similar metalated product [Cp(OAr′)Ti-
(SCHMe)]2, which has been structurally characterized.1
The analogous reaction of 1 equiv of phenylthiol with
13 led to a mixture of 15 and the species (t-Bu3PN)2Ti-
(Me)(SPh) 18. However, in contrast, reaction of 13 with
tert-butylthiol afforded (t-Bu3PN)2Ti(Me)(St-Bu) 19 in
89% isolated yield. Presumably, the steric demands of
the thiol in the latter case preclude formation of the
dithiolate derivative 16.
Meunier et al. have shown that early metal chalco-
genates can be derived from the reaction of metallocene-
dialkyls with elemental S, Se, or Te.20 In attempts to
effect similar sulfur insertion into Ti-Me bonds, the
reaction of (t-Bu3PN)2TiMe2 13 with S8 in toluene was
performed. Workup of the resulting bright yellow solu-
tion afforded not the dithiolate, but rather the species
(t-Bu3PN)2Ti(η2-S5) 20 in 85% yield. The solid-state
structure of 20 (Figure 6) reveals a pseudo-tetrahedral
geometry about Ti. The phosphinimide ligands adopt a
F igu r e 6. ORTEP drawing of 20; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Distances in Å, angles in deg: Ti(1)-N(1) 1.8092(17), Ti-
(1)-N(2) 1.8124(17), Ti(1)-S(5) 2.4204(7), Ti(1)-S(1) 2.4243-
(7), Ti(1)-S(2) 2.8711(8), Ti(1)-S(4) 2.8935(8), S(1)-S(2)
2.0375(10), S(2)-S(3) 2.0608(10), S(3)-S(4) 2.0763(10),
S(4)-S(5) 2.0290(10), P(1)-N(1) 1.5842(18), P(2)-N(2)
1.5767(17), N(1)-Ti(1)-N(2) 113.35(8), N(1)-Ti(1)-S(5)
107.05(6), N(2)-Ti(1)-S(5) 102.69(6), N(1)-Ti(1)-S(1)
104.30(6), N(2)-Ti(1)-S(1) 107.97(6), S(5)-Ti(1)-S(1)
121.80(3), N(1)-Ti(1)-S(2) 142.48(6), N(2)-Ti(1)-S(2) 98.38-
(6), S(5)-Ti(1)-S(2) 83.67(2), S(1)-Ti(1)-S(2) 44.26(2),
N(1)-Ti(1)-S(4) 95.90(6), N(2)-Ti(1)-S(4) 142.41(6), S(5)-
Ti(1)-S(4) 43.78(2), S(1)-Ti(1)-S(4) 85.65(2), S(2)-Ti(1)-
S(4) 66.72(2), S(2)-S(1) Ti(1) 79.59(3), S(1)-S(2)-S(3)
108.21(4), S(1)-S(2)-Ti(1) 56.15(2), S(3)-S(2)-Ti(1) 97.11-
(3), S(2)-S(3)-S(4) 100.04(4), S(5)-S(4)-S(3) 107.96(4),
S(5)-S(4)-Ti(1) 55.62(2), S(3)-S(4)-Ti(1) 96.07(3), S(4)-
S(5)-Ti(1) 80.61(3), P(1)-N(1)-Ti(1) 174.07(12), P(2)-
N(2)-Ti(1) 175.58(12).
product is unstable and evolves CH4 over a couple of
hours to give a cyclometalated species (t-Bu3PN)2Ti(η2-
SCHPh) 17. This compound exhibits two 31P{1H} NMR
resonances at 26.6 and 27.9 ppm, as a result of the
phosphinimide groups syn and anti to the phenyl group.
A
1H NMR resonance at 4.85 ppm is assigned the
metalated methine proton, while a 13C{APT} NMR
(20) Meunier, P.; Gautheron, B.; Mazouz, A. J . Organomet. Chem.
1987, 320, C39-C43.

1652 Organometallics, Vol. 21, No. 8, 2002
Ong et al.
F igu r e 8. ORTEP drawing of 22; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Distances in Å, angles in deg: Ti(1)-C(15) 1.902(2), Ti-
(1)-N(1) 2.0047(19), Ti(1)-S(1) 2.4712(7), S(1)-C(21) 1.776-
(3), S(1)-Al(1) 2.4573(11), S(2)-C(27) 1.778(3), S(2)-Al(3)
2.3713(9), S(2)-Al(2) 2.4636(10), P(1)-N(1) 1.601(2), N(1)-
Al(3) 1.877(2), C(15)-Ti(1)-N(1) 92.67(9), C(15)-Ti(1)-
S(1) 92.59(7), N(1)-Ti(1)-S(1) 105.64(6), C(21)-S(1)-Al(1)
123.28(11), C(21)-S(1)-Ti(1) 115.82(9), Al(1)-S(1)-Ti(1)
73.95(3), C(27)-S(2)-Al(3) 114.68(9), C(27)-S(2)-Al(2)
120.08(10), Al(3)-S(2)-Al(2) 76.18(3), P(1)-N(1)-Al(3)
130.61(12), P(1)-N(1)-Ti(1) 141.66(12), Al(3)-N(1)-Ti(1)
87.14(8), C(16)-Al(1)-C(17) 117.53(18), C(16)-Al(1)-C(15)
114.39(13), C(17)-Al(1)-C(15) 114.54(14), C(16)-Al(1)-
S(1) 102.47(12), C(17)-Al(1)-S(1) 113.04(12), C(15)-Al-
(1)-S(1) 90.90(7), C(19)-Al(2)-C(18) 113.34(15), C(19)-
Al(2)-C(15) 118.39(12), C(18)-Al(2)-C(15) 115.81(12),
C(19)-Al(2)-S(2) 107.13(12), C(18)-Al(2)-S(2) 112.48(10),
C(15)-Al(2)-S(2) 85.97(7), N(1)-Al(3)-C(20) 120.25(12),
N(1)-Al(3)-C(15) 93.58(9), C(20)-Al(3)-C(15) 127.19(12),
N(1)-Al(3)-S(2) 111.90(7), C(20)-Al(3)-S(2) 110.99(10),
C(15)-Al(3)-S(2) 88.23(7), Ti(1)-C(15)-Al(2) 141.60(13),
Ti(1)-C(15)-Al(1) 99.23(10), Al(2)-C(15)-Al(1) 111.02(11),
Ti(1)-C(15)-Al(3) 86.62(9), Al(2)-C(15)-Al(3) 96.91(10),
Al(1)-C(15)-Al(3) 121.07(12).
F igu r e 9. ORTEP drawing of 23; 30% thermal ellipsoids
are shown. Hydrogen atoms have been omitted for clarity.
Distances in Å, angles in deg: Ti(1)-C(15) 1.945(6), Ti-
(1)-N(1) 2.055(5), Ti(1)-S(1) 2.503(2), Al(1)-N(1) 1.929-
(6), Al(1)-C(16) 2.001(8), Al(1)-C(15) 2.050(7), Al(1)-S(2)
2.422(3), Al(2)-C(17) 2.015(8), Al(2)-C18 2.027(8), Al(2)-
C(15) 2.064(7), Al(2)-S(1) 2.440(3), Al(3)-C(20) 2.022(10),
Al(3)-C(19) 2.028(9), Al(3)-C(15) 2.032(7), Al(3)-S(2)
2.465(3), S(1)-C(21) 1.909(9), S(2)-C25 1.925(10), P(1)-
N(1) 1.644(5), C(15)-Ti(1)-N(1) 92.8(2), C(15)-Ti(1)-S(1)
90.6(2), N(1)-Ti(1)-S(1) 103.79(16), N(1)-Al(1)-C(16)
119.7(3), N(1)-Al(1)-C(15) 93.5(2), C(16)-Al(1)-C(15)
125.8(3), N(1)-Al(1)-S(2) 112.1(2), C(16)-Al(1)-S(2) 113.7-
(3), C(15)-Al(1)-S(2) 86.7(2), C(17)-Al(2)-C18 113.0(4),
C(17)-Al(2)-C(15) 114.4(3), C(18)-Al(2)-C(15) 117.0(4),
C(17)-Al(2)-S(1) 116.4(3), C(18)-Al(2)-S(1) 104.0(3),
C(15)-Al(2)-S(1) 89.7(2), C(20)-Al(3)-C(19) 114.6(5),
C(20)-Al(3)-C(15) 113.2(4), C(19)-Al(3)-C(15) 119.5(4),
C(20)-Al(3)-S(2) 111.8(3), C(19)-Al(3)-S(2) 107.8(3),
C(15)-Al(3)-S(2) 86.0(2), C(21)-S(1)-Al(2) 121.6(3), C(21)-
S(1)-Ti(1) 131.9(3), Al(2)-S(1)-Ti(1) 75.37(8), C(25)-
S(2)-Al(1) 124.8(5), C(25)-S(2)-Al(3) 115.8(4), Al(1)-
S(2)-Al(3) 77.16(10), P(1)-N(1)-Al(1) 131.8(3), P(1)-
N(1)-Ti(1) 140.7(3), Al(1)-N(1)-Ti(1) 87.0(2), Ti(1)-C(15)-
Al(3) 143.0(4), Ti(1)-C(15)-Al(1) 86.7(3), Al(3)-C(15)-
Al(1) 96.6(3), Ti(1)-C(15)-Al(2) 97.8(3), Al(3)-C(15)-Al(2)
110.3(3), Al(1)-C(15)-Al(2) 123.8(3).
geometry similar to that observed in 14 and 16. The
Ti-S distances were found to be 2.4204(7) and 2.4243-
(7) Å. These distances are slightly shorter than those
seen in Cp2Ti(η2-S5) (2.45 Å),21 consistent with the
greater Lewis acidity of the Ti center in 20. Presumably
this also accounts for the approach of the â-S atoms to
the Ti center at distances of 2.8711(8) and 2.8935(8) Å.
S-S distances range from 2.0290(10) to 2.0763(10) Å.
Rea ctivity. Having prepared this series of Ti-thiolate
derivatives, reactions of 3-5 with excess AlMe3 were
investigated.14 Upon standing of the reaction mixtures
over a 24 h period at 25 °C, new 31P{1H} NMR
resonances replaced those of the starting materials,
inferring the quantitative formation of new species 21-
23, respectively. These species were isolated in 83%,
although the precise nature of the molecular structure
remained unclear. However, the species 23 was also
obtained in the reaction of the previously reported
species CpTi(µ-Me)(µ-NPi-Pr3)(µ-C)(AlMe3)315 with HSt-
Bu, suggesting a Ti-Al-carbide aggregate structure.
Crystallographic studies of 21-23 confirmed that these
species are analogous and are formulated as (CpTi(µ-
SR)(µ-NPi-Pr3)(C)(AlMe2)2(µ-SR)AlMe (R ) CH2Ph 21,
Ph 22, t-Bu 23) (Figures 7-9). In these molecules, the
pseudo-“three-legged piano stool” coordination sphere
of Ti is comprised of a cyclopentadienyl ring, a thiolate-
sulfur, a phosphinimide-nitrogen, and a carbide carbon.
Three Al atoms complete the bonding sphere of the
carbide. An AlMe2 moiety bridges the Ti-bound thiolate
and the carbide; a second AlMe2 fragment is coordinated
to a second thiolate group, which also bridges to a third
Al center. This latter AlMe moiety is bonded to the Ti-
bound phosphinimide-N. The majority of the metric
parameters are unexceptional. The most interesting
feature is the geometry about the carbide carbon atoms.
The Ti-carbide distances in 21-23 are 1.900(3), 1.902-
(2), and 1.945(6) Å, respectively. The slightly longer
Ti-C distance in 23 is consistent with both greater
basicity and steric demands of the tert-butylthiolate
ligands. These distances are significantly shorter than
the terminal Ti-CH3 distance in Cp(t-Bu3PN)TiMe(µ-
1
74%, and 56% yield, respectively. H NMR spectra of
these compounds revealed resonances attributable to
two inequivalent thiolate ligands and cyclopentadienyl
and phosphinimide ligands. In addition, each exhibited
five resonances between 0.30 and -0.32 ppm attribut-
able to Al-methyl groups. The corresponding 13C{1H}
NMR resonances for the ligand fragments were ob-
served, while the signals for the methyl carbons were
extremely weak, consistent with Al-bound methyl groups.
On the basis of these NMR data, formulations incorpo-
rating a Ti and three Al atoms could be proposed,
(21) Draganjac, M.; Rauchfuss, T. B. Angew. Chem., Int. Ed. Engl.
1985, 24, 742-757.

Titanium Phosphinimide Thiolate Complexes
Organometallics, Vol. 21, No. 8, 2002 1653
Sch em e 2
reasonable to suggest that interaction of the AlMe3 with
the S and N atom donors in the Ti complexes accounts
for the association of 3 equiv of AlMe3. It is noteworthy
that even on standing in the presence of excess AlMe3
for extended periods 24 and 25 do not undergo methyl-
thiolate exchange nor C-H activation. This stands in
contrast to the monodentate-thiolate precursors, sug-
gesting that the chelate effect in the dithiolate ligand
complexes arrests further reaction.
The formation of 24 and 25 suggests the initial
interaction between AlMe3 and a Ti-thiolate complex is
via the donor atoms. Clearly, such adducts could lead
to facile methyl for thiolate exchange, which is ulti-
mately inferred by the nature of the product. Ligand
for methyl exchange has been observed previously as
in reactions of CpTi(OAr′)2Cl with AlMe3.22 In addition,
methyl exchange between AlMe3 and the carbides CpTi-
(µ2-Me)(µ2-NPR3)(µ4-C)(AlMe2)3 and CpTi(µ2-Me)(µ2-
NPR3)(µ4-C)(AlMe2)4 has been established as a rapid and
facile process by labeling experiments.15 Subsequent
C-H bond-activating steps liberating methane are
thought to result from the proximity of the ligand-bound
Al-Me fragments and the intermediate Ti-bound methyl
group. The mechanistic details of such C-H bond
activation reactions are unknown and are the subject
of ongoing studies.
CH3B(C6F5)3) (2.123(5) Å),7 presumably a result of the
increase in the Lewis acidity at the Ti center due to
diminished donation from S and N donors. The geom-
etry about the carbide centers can best be described as
severely distorted from a tetrahedral geometry. The Ti-
C-Al and Al-C-Al angles range as high as 143.0(4)°
and 123.8(3)°, respectively. These distortions are con-
sistent with the carbide being central to three fused
four-membered rings where the corresponding Ti-C-
Al and Al-C-Al angles range from 86.6(7)° to 97.0(6)°.
Analogous reactions of chelate dithiolate complexes
7 and 8 with AlMe3 over a period of 10 h with excess
AlMe3 resulted in the formation of the new complexes
24 and 25 in 78% and 55% yields, respectively. NMR
data showed the formation of new species, as the 1H
resonances were downfield shifted and new broad peaks,
attributed to AlMe3 fragments, appeared at -0.11 and
0.14 ppm. Integration suggested the association of 3
equiv of AlMe3 with the precursor complexes and thus
the formulas [Cp(i-Pr3PN)Ti(SRS)]‚(AlMe3)3 (R ) (CH2)3
24, ((CH2)2(C6H4)) 25). The resonance attributed to
AlMe3 groups remained broad even on cooling to -80
°C, suggesting a highly fluxional molecule. Although the
precise structures of 24 and 25 are not known, it is
Ack n ow led gm en t . Financial support from the
NSERC of Canada and NOVA Chemicals Corporation
is gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Crystallographic
data and NMR spectra. This material is available free of
charge via the Internet at http://pubs.acs.org.
OM011042E
(22) Firth, A. V.; Stephan, D. W. Inorg. Chem. 1998, 37, 4732-4734.