Organometallic and related imidotitanium compounds containing a pendant arm functionalised benzamidinate ligand

Article abstract of DOI:10.1016/S0022-328X(03)00462-5

Chloride ligand substitution reactions of tert-butyl- and arylimido-titanium complexes supported by the pendant arm functionalised N-trimethylsilyl benzamidinate ligand Me₃SiNC(Ph)NCH ₂CH₂CH₂NMe₂ are described. Reaction of previously-described [Ti(N^tBu){Me₃SiNC (Ph)NCH₂CH₂CH₂NMe₂}Cl] (1) with PhLi afforded thermally sensitive [Ti(N^tBu) {Me₃SiNC(Ph)NCH₂CH₂CH₂ NMe₂}Ph] (2). The corresponding reaction of 1 with MeLi afforded [Ti(N^tBu){Me₃SiNC(Ph)NCH₂ CH₂CH₂NMe₂}Me] (3) detected by ¹H-NMR spectroscopy but this compound could not be isolated. Reaction of 1 with LiCH₂SiMe₃ gave a complex mixture, but with LiN(SiMe₃)₂ and LiO-2,6- C₆ H₃Me₂ the compounds [Ti(N^tBu) {Me₃SiNC(Ph)NCH₂CH ₂CH₂ NMe₂}X] (X=N(SiMe₃) ₂ (4) or O-2,6-C₆H₃Me₂ (5)) were isolated. The X-ray structure of 5 was determined. Reaction of the homologous compound [Ti(N^tBu){Me₃SiNC(Ph) NCH₂CH₂ NMe₂}Cl] (6) (containing a 2-carbon atom chain in the pendant arm) with MeLi or PhLi were unsuccessful although the aryloxide compound [Ti(N^tBu) {Me₃SiNC(Ph)NCH₂CH₂ NMe₂} (O-2,6-C₆H₃Me₂)] (7) could be isolated from the reaction of 6 with LiO-2,6-C₆ H₃ Me₂. Reaction of the 3-carbon pendant arm arylimido compound [Ti(N-2,6-C₆H₃Me₂) {Me₃ SiNC(Ph)NCH₂CH₂CH₂ NMe₂}Cl] (8) with MeLi afforded thermally sensitive [Ti(N-2,6-C₆ H₃Me₂){Me₃SiNC (Ph)NCH₂ CH₂CH₂NMe₂}Me] (9), and although the analogous phenyl homologue was elusive, the aryloxide derivative [Ti(N-2,6-C₆H₃Me₂) {Me₃ SiNC(Ph)NCH₂CH₂CH₂ NMe₂} (O-2,6-C₆H₃Me₂)] (10) was successfully isolated and structurally characterised. Comparison of the X-ray structures of 5 and 10 show unexpectedly large differences between the Ti=NR and Ti=OAr bond lengths in the two compounds.

Full text of DOI:10.1016/S0022-328X(03)00462-5

Journal of Organometallic Chemistry 683 (2003) 120Á130
/
www.elsevier.com/locate/jorganchem
Organometallic and related imidotitanium compounds containing a
pendant arm functionalised benzamidinate ligand
A.Charis R. Croft, Catherine L. Boyd, Andrew R. Cowley, Philip Mountford *
Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, UK
Received 27 March 2003; received in revised form 5 May 2003; accepted 5 May 2003
Abstract
Chloride ligand substitution reactions of tert-butyl- and arylimido-titanium complexes supported by the pendant arm
functionalised N-trimethylsilyl benzamidinate ligand Me3SiNC(Ph)NCH2CH2CH2NMe2 are described. Reaction of previously-
described [Ti(NtBu){Me3SiNC(Ph)NCH2CH2CH2NMe2}Cl] (1) with PhLi afforded thermally sensitive [Ti(NtBu){Me3-
SiNC(Ph)NCH2CH2CH2NMe2}Ph] (2). The corresponding reaction of
1
with MeLi afforded [Ti(NtBu){Me3-
SiNC(Ph)NCH2CH2CH2NMe2}Me] (3) detected by 1H-NMR spectroscopy but this compound could not be isolated. Reaction
of 1 with LiCH2SiMe3 gave a complex mixture, but with LiN(SiMe3)2 and LiO-2,6-C6H3Me2 the compounds [Ti(NtBu){Me3-
SiNC(Ph)NCH2CH2CH2NMe2}X] (XꢀN(SiMe3)2 (4) or O-2,6-C6H3Me2 (5)) were isolated. The X-ray structure of 5 was
/
determined. Reaction of the homologous compound [Ti(NtBu){Me3SiNC(Ph)NCH2CH2NMe2}Cl] (6) (containing a 2-carbon atom
chain in the pendant arm) with MeLi or PhLi were unsuccessful although the aryloxide compound [Ti(NtBu){Me3-
SiNC(Ph)NCH2CH2NMe2}(O-2,6-C6H3Me2)] (7) could be isolated from the reaction of 6 with LiO-2,6-C6H3Me2. Reaction of
the 3-carbon pendant arm arylimido compound [Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}Cl] (8) with MeLi
afforded thermally sensitive [Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}Me] (9), and although the analogous phenyl
homologue was elusive, the aryloxide derivative [Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-C6H3Me2)] (10)
was successfully isolated and structurally characterised. Comparison of the X-ray structures of 5 and 10 show unexpectedly large
differences between the TiÄ
/
NR and TiÃ
/
OAr bond lengths in the two compounds.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Titanium; Imido; Benzamidiate ligands; Amide; Aryloxy; Methyl; Phenyl
1. Introduction
ligand(s). In some cases there might well be ambiguity
in regard to the actual site of reactivity.
Transition metal imido compounds provide a wealth
An interesting question concerning reaction site
selectivity has been raised recently by Jensen and Børve
[3] in calculations on Gibson’s olefin polymerisation
of molecular reactivity, this occurring either at the Mꢀ
/
NR linkage itself (i.e. imido ligand as a reactive site) or
at some other point in the LnM(NR) coordination
sphere (imido ligand acting as a supporting group)
[1,2a,b]. Both types of reactivity are well-established,
and in recent years we have been interested to exploit the
chemistry of imidotitanium compounds in both of these
regards [2]. Clearly the type of reactivity exhibited by an
imido compound depends on the nature of the sub-
strate(s) involved and the identity of the ancilliary
catalysts [Cr(NR?)2R2] (R?ꢀt
/
Bu or aryl; RꢀMe or
/
CH2Ph) [4]. At first sight, one would probably envisage
that these would give rise to cationic active species
‘[Cr(NR?)2R]ꢁ’ (Rꢀ
/
initiating alkyl group or growing
polymer chain) with monomer enchainment proceeding
through migratory insertion reactions of the CrÃ
/R
bond. However, for chemically realistic model systems
[Cr(NR?)2R]ꢁ it appears that [3] ethylene cycloaddition
to the Crꢀ
/
NR? bond can compete with insertion into
the CrÃR bond, in turn leading (after further modifica-
/
tion) to a reduced Cr (IV) species which may in fact be
the resting state for this catalyst system. In very recent
* Corresponding author. Fax: ꢁ44-186-527-2690.
E-mail address: philip.mountford@chem.ox.ac.uk (P. Mountford).
/
0022-328X/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00462-5

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130
121
work, we ourselves reported that the cationic imido-
tungsten methyl compound [W{MeC(2-C5H4N)-
tion (i.e. do not engage in temperature-dependent
dynamic equilibria) as compared with I/II. Furthermore,
the pendant NMe2 donor group of the Me3-
SiNC(Ph)N(CH2)nNMe2 ancillary ligands in IV might,
in principle, dissociate in solution (or during the course
of a reaction) to form a more reactive, lower coordina-
tion number metal centre (an approach we have used
with considerable success in other N-donor ligand
supported imidotitanium systems 2b). We therefore
anticipated that replacement of the chloride ligand in
certain of the compounds [Ti(NR){Me3SiNC(Ph)-
N(CH2)nNMe2}Cl] (IV) would provide interesting and
well-defined metal complexes for the further study of
imidotitanium chemistry. An investigation of this pos-
sibility is the subject of our present contribution [12].
(CH2NSiMe3)2}(NPh)Me]ꢁ (anionꢀ[MeB(C6F5)3]ꢂ)
/
reacts with CO2 or isocyanates appear to undergo
cycloaddition reactions at the WÄNPh bond and not
insertion into the WÃMe bond [5,6]. This is despite the
/
/
latter product being the most thermodynamically fa-
vourable according to DFT calculations, and insertion
reactions of CO2 into W-alkyl bonds being extremely
well precedented in the literature. With these and other
observations in mind we have been interested to prepare
new imido complexes containing potentially reactive
Mꢀ
metalÃ
We have previously reported amidinate [5Á
ported imidotitanium complexes [8] [Ti(NR){PhC(NSi-
Me3)2}Cl(py)n] (nꢀ Bu or aryl*see
2 (I) or 1 (II); Rꢀt
/NR linkages, and which additionally contain
/hydrocarbyl s-bonds.
/7] sup-
/
/
/
Chart 1) and [Ti2(m-NtBu)2{MeC(NC6H11)2}2Cl2].
Chloride ligand metathesis reactions of I/II (which exist
in a dynamic, temperature-dependent equilibrium) yield
alkyl, borohydride, amide, aryloxide and cyclopentadie-
nyl derivatives [9]. Some of the latter family of
complexes, namely [Ti(NAr)(h-C5Me5){MeC(NiPr)2}]
2. Results and discussion
2.1. Syntheses
The starting compounds [Ti(NR){Me3SiNC(Ph)-
NCH2CH2CH2NMe2}Cl] (Rꢀt
Bu 1 or 2,6-C6H3Me2
(III, Arꢀsubstituted phenyl group), react with CO2
/
/
(8)) and [Ti(NtBu){Me3SiNC(Ph)NCH2CH2NMe2}Cl]
(6) were prepared as previously-described [11] by reac-
tion of [Ti(NR)Cl2(py)3] [13] with the corresponding
lithiated amidinates Li{Me3SiNC(Ph)NCH2CH2CH2-
NMe2} [14] and Li{Me3SiNC(Ph)NCH2CH2NMe2}
[15]. We have focussed most of our efforts on the 3-
carbon pendant arm systems 1 and 8 since previous
studies [11] showed these are the most easily handled
and give rise to fewer unwanted side-reactions.
(via an initial cycloaddition reaction) to form [Ti(h-
C5Me5){MeC(NiPr)2}{O(CO)N(Ar)(CO)O}]; the dou-
ble CO2 activation reaction leading to these compounds
was the first example for any transition metal imide [10].
To develop this promising line of study, we more
recently [11] reported complexes of the type
[Ti(NR){Me3SiNC(Ph)N(CH2)nNMe2}Cl] (nꢀ
Rꢀt
Bu or aryl, IV) containing pendant amino donor
groups. These form better defined compounds in solu-
/2 or 3,
/
Chart 1.

122
A.C.R. Croft et al. / Journal of Organometallic Chemistry 683 (2003) 120Á130
/
The syntheses and proposed structures of the new
compounds are summarised in Scheme 1 and Eq. (1).
Reaction of [Ti(NtBu){Me3SiNC(Ph)NCH2CH2CH2N-
composition. The NMR spectra of 2 are consistent with
the structure proposed in Scheme 1. The presence of the
titanium-bound phenyl group is established by doublet,
triplet and multiplet resonances at 8.31, 7.46 and 7.33,
respectively in the 1H-NMR spectrum. Additional
resonances characteristic of a tert-butyl group and a
k3-bound Me3SiNC(Ph)NCH2CH2CH2NMe2 ligand
were clearly visible. That the dimethylamino nitrogen
is firmly bound to titanium (i.e. does not dissociate
rapidly on the NMR timescale) was confirmed by the
presence of two singlets (integration 3H each with
respect to that for tert-butyl) for the N-methyl groups,
and six individual methylene proton resonances for the
Me2}Cl] (1) with PhLi at ꢂ80 8C in Et2O gave a yellow
/
solution which, on warming to room temperature,
darkened markedly. Removal of the volatiles and
extraction into benzene (to separate LiCl) afforded the
phenyl compound [Ti(NtBu){Me3SiNC(Ph)NCH2-
CH2CH2NMe2}Ph] (2) as a brown/black solid. Solu-
tions of 2 were very clean by NMR spectroscopy but
clearly degraded over time in the dark (at room
temperature in deuterobenzene), indicating the thermal
sensitivity of the sample. Attempts to recrystallise 2
resulted in further degradation. Somewhat surprisingly,
a parent molecular ion was observed in the high
resolution EI mass spectrum confirming the elemental
1
CH2CH2CH2 linkage in the H-NMR spectrum.
Attempts were made to make better behaved/more
stable s-hydrocarbyl derivatives of 1. Reaction of 1 with
Scheme 1.

A.C.R. Croft et al. / Journal of Organometallic Chemistry 683 (2003) 120Á
/
130
123
MeLi in C6D6 on an NMR tube scale gave clean
conversion to the methyl derivative [Ti(NtBu){Me3-
SiNC(Ph)NCH2CH2CH2NMe2}Me] (3) as judged by
1H-NMR spectroscopy. In addition to resonances for
the tert-butyl and Me3SiNC(Ph)NCH2CH2CH2NMe2
groups a further singlet at 0.79 (relative integral 3H) was
reproducibly observed. The compound did not appear
to be especially light- or temperature-sensitive in solu-
tion, but attempts to scale up the reaction on a
preparative scale were unsuccessful (see, however, the
successful synthesis of the arylimido homologue 9
below). Reaction of 1 with LiCH2SiMe3 in C6D6 gave
a complex mixture. This was particularly disappointing
since we had previously found 8a that the analogous
reaction of [Ti(NtBu){PhC(NSiMe3)2}Cl(py)2] gave rea-
sonable yields of crystallographically characterised
[Ti(NtBu){PhC(NSiMe3)2}(CH2SiMe3)(py)].
(1)
products we investigated certain chloride substitution
reactions of the corresponding 2-carbon pendant arm
system [Ti(NtBu){Me3SiNC(Ph)NCH2CH2NMe2}Cl]
(6) [11]. Reaction of 6 with LiO-2,6-C6H3Me2 (Eq. (1))
gave [Ti(NtBu){Me3SiNC(Ph)NCH2CH2NMe2}(O-2,6-
C6H3Me2)] (7) as a yellow crystalline material in 25%
recrystallised yield. The NMR resonances for the
Ti(NtBu){Me3SiNC(Ph)NCH2CH2NMe2} moiety in 7
are comparable to those of 6. The ortho methyl groups
in the room temperature 1H and 13C spectra of 7 appear
as a single resonances (the meta ring protons and
carbons could not be clearly assigned due to overlap
with resonances from the amidinate phenyl group). Thus
Reaction of 1 with LiN(SiMe3)2 gave [Ti(NtBu){Me3-
SiNC(Ph)NCH2CH2CH2NMe2}{N(SiMe3)2}] (4) as a
highly soluble, yellow crystalline solid. It was not wholly
possible to recrystallise 4 away from impurities which
evidently possess similar solubility characteristics. How-
ever, resonances for the tert-butyl and amidinate moities
in 4 were similar to those found for 2 and 3. The bulky
N(SiMe3)2 substituent appeared as two singlets (relative
1
intensity 9H each) in the H-NMR spectrum, consistent
with restricted rotation about the TiÃ
/
N bond.
restricted rotation about the TiÃ
/
O bond of 7 at room
To establish structurally that Cl-substitution products
of 1 possess the geometries proposed in Scheme 1, the
comparatively stable aryloxide derivative [Ti(Nt-
Bu){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-
temperature (at the same spectrometer field as for 5) is
not observed, possibly implying that the coordination
environment about titanium in 7 is not as crowded as
that in 5. Unfortunately, reaction of 6 with MeLi or
PhLi both failed to give rise to isolable products,
although the NMR tube scale reaction with MeLi
looked fairly promising (just as for 1).
C6H3Me2)] (5) was prepared. Thus reaction of 1 with
LiO-2,6-C6H3Me2 in toluene followed by recrystallisa-
tion from hexanes afforded yellow crystalline 5 in 63%
isolated yield. The compound 5 has been crystallogra-
phically characterised (see below) and this confirmed the
structure proposed in Scheme 1. The NMR data for the
{Ti(NtBu)(Me3SiNC(Ph)NCH2CH2CH2NMe2)} moi-
ety of 5 are analogous to those of the organometallic
homologues 2 and 3. Additional resonances for a 2,6-
C6H3Me2 moiety are also observed, the methyl and
meta ring protons of which appear as four individual
signals. This evidence of restricted rotation about the
Certain comparative reactions of the arylimido com-
pound [Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)NCH2CH2-
CH2NMe2}Cl] (8) [11] were investigated (Scheme 1).
NMR tube scale reactions with PhLi in C6D6 gave
complex mixtures, but with MeLi in cold Et2O the
methyl derivative [Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)-
NCH2CH2CH2NMe2}Me] (9) was obtained as brown,
thermally sensitive solid in 50% isolated yield. The
NMR spectra for 9 are consistent with the structure
proposed in Scheme 1. Notably, the titanium-bound
methyl group appears at 0.95 ppm in the 1H-NMR
spectrum (38.20 in the 13C spectrum) which is compar-
able to that for [Ti(NtBu){Me3SiNC(Ph)NCH2-
CH2CH2NMe2}Me] (3), i.e. 0.79 ppm.
For comparative purposes the reaction of 8 with LiO-
2,6-C6H3Me2 was carried out. This afforded [Ti(N-2,6-
C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-
C6H3Me2)] (10) as an orange solid in 63% yield. The
solid state structure has been determined (see below) and
confirms that illustrated in Scheme 1. As for 7 (and in
contrast to that found for 5) there is no evidence for
TiÃ/O bond on the NMR timescale indicates that the
coordination environment around titanium in 5 (as also
found in 4 above) is in fact quite crowded. The
corresponding benzamidinate compound without a
pendant arm, namely [Ti(NtBu){PhC(NSiMe3)2}(O-
2,6-C6H3Me2)(py)] 8a, did not exhibit evidence for an
analogous restricted rotation at room temperature
(although the 2,6-di-tert-butyl homologue [Ti(Nt-
Bu){PhC(NSiMe3)2}(O-2,6-C6Ht3Bu2)(py)] did) (Eq.
(1)).
Speculating that the greater steric crowding associated
with the Me3SiNC(Ph)NCH2CH2CH2NMe2 ligand
might be contributing to the instability of some of the

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A.C.R. Croft et al. / Journal of Organometallic Chemistry 683 (2003) 120Á130
/
restricted rotation about the TiÃ
/
O bond on the NMR
with N(1), O(1) and N(3) formally occupying the
equatorial positions. Clearly both structures are con-
strained by the chelating amidinate ligand and inher-
ently small bite angle of the N2CPh moiety. Four five-
coordinate, crystallographically characterised arylimi-
dotitanium compounds containing two monodentate
aryloxide ligands and two Lewis base donor atoms
timescale at room temperature.
2.2. X-ray structures
The molecular structures of [Ti(NtBu){Me3-
SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-C6H3Me2)] (5)
have been described previously [17Á19]. Two of these
/
and
[Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)NCH2CH2-
[18,19] feature bidentate Lewis base donors and are thus
somewhat constrained. The other two are of the type
CH2NMe2}(O-2,6-C6H3Me2)] (10) are shown in Figs. 1
and 2, and selected bond distances and angles are
presented in Table 1. For comparison, corresponding
values for [Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)NCH2-
CH2CH2NMe2}Cl] (8) [11] are also listed.
Molecules of 5 and 10 possess monomeric, five-
coordinate structures in the solid state. All three
nitrogens of the Me3SiNC(Ph)NCH2CH2CH2NMe2 li-
gands are firmly coordinated to titanium with similar
[Ti(NAr)(OAr?)2(L)2] (Arꢀ
phenyl; Lꢀpyridine or substituted pyridine) and pos-
sess well-defined trigonal bipyramidal geometries with
ArNÄTiÃO angles of ca. 113Á1148 and ArNꢀTiÃ
angles of ca. 96Á998. The compounds 5 and 10 are the
/
phenyl or 2,6-disubtituted
/
/
/
/
/
/L
/
first structurally characterised imidotitanium com-
pounds featuring only one aryloxide ancillary ligand.
Turning now to the Tiꢀ
/
NR and TiÃ
/
OAr units, it is
interesting to note the significant differences between the
TiÃ
analogues
CH2CH2NMe2}Cl] (Rꢀ
/
N distances to those found previously in the chloride
[Ti(N-2,6-C6H3R2){Me3SiNC(Ph)NCH2-
two TiÄ
/
NR distances for Rꢀt
Bu (1.6991(15) A) and
˚
/
i
/
Me 8 or Pr) [11]. The N(3)
˚
and N(4) atoms are approximately sp2 hybridised as
indicated by their approximately trigonal planar geo-
metry (the sums of the angles subtended at the N(3) and
Rꢀ2,6-C6H3Me2 (1.756(2) A), and the two TiÃ
/
/
OAr
˚
˚
distances (1.8887(13) A for 5; 1.828(2) A for 10). The
previously established ranges are as follows [16]: for
terminal TiÄ
A with a range of 1.656(9)Á
/
NtBu linkages the mean value is 1.702(18)
N(4) atoms lie in the range 353.8(4)Á
/
358.7(5)8). The TiÃ
/
˚
˚
/
1.738(4) A; for terminal TiÄ
/
N distances to the amidinate ligand are significantly
longer for 5 than for 10 as expected based on the better
donor ability of tert-butylimido ligands compared to
their arylimido homologues [16,12b,13].
While the geometry at Ti(1) in 5 and 10 may be
reasonably well described as distorted square base
pyramidal (with N(1) occupying the axial position),
that of 10 is somewhat closer to trigonal bipyramidal
˚
N-2,6-C6H3Me2 linkages the mean value is 1.725(16) A
˚
with a range of 1.695(8)Á
/
1.752(8) A; for TiÃ
/OAr
linkages with two ortho-methyl (or sterically similar)
˚
substituents the mean value is 1.825(46) A with a range
˚
1.952(4) A. For the four arylimidotitanium
of 1.735(7)Á
/
compounds containing two monodentate aryloxide
ligands and two Lewis base donor atoms mentioned
Fig. 1. Molecular structure of [Ti(Nt Bu){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-C6H3Me2)] (5). Displacement ellipsoids are drawn at the 20%
probability level. H atoms omitted for clarity.

A.C.R. Croft et al. / Journal of Organometallic Chemistry 683 (2003) 120Á
/
130
125
Fig. 2. Molecular structure of [Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-C6H3Me2)] (10). Displacement ellipsoids are drawn
at the 20% probability level. H atoms and hexane molecule of crystallisation omitted for clarity.
above the average TiÄ
/
NAr distance is 1.721(4) (range
3. Experimental
˚
1.709(5)Á
/
1.734(4) A) and the average TiÃOAr distance
/
˚
1.932(3) A). The angles
is 1.882(9) (range 1.853(4)Á
/
3.1. Literature preparations
subtended at N(1) and O(1) are approximately linear
for these four compounds and for 5 and 10, indicating
that in all instances these atoms are effectively sp
hybridised and the imido and aryloxide groups can, in
principle, donate four or five electrons respectively to
titanium [12b,20], subject to orbital availability. While
The compounds [Ti(NR){Me3SiNC(Ph)NCH2CH2-
CH2NMe2}Cl] (Rꢀt
Bu 1 or 2,6-C6H3Me2 8) and
/
[Ti(NtBu){Me3SiNC(Ph)NCH2CH2NMe2}Cl] (6) were
prepared as reported previously [11].
the actual TiÄ
(within error) within the previously determined general
ranges of values, there is an unexpectedly large differ-
/
NR and TiÃ
/
OAr distances in 5 and 10 lie
3.2. General methods and instrumentation
All manipulations were carried out using standard
Schlenk line or drybox techniques under an atmosphere
of argon or of dinitrogen. Solvents were predried over
ence between the TiÄ
/
NR and TiÃ
/OAr distances be-
tween the two molecules. Furthermore, when specifically
comparing the data for 10 with those for the previous
four arylimidotitanium compounds containing two
˚
activated 4 A molecular sieves and were refluxed over
appropriate drying agents under a dinitrogen atmo-
sphere and collected by distillation. Deuterated solvents
were dried over appropriate drying agents, distilled
under reduced pressure, and stored under dinitrogen in
Teflon valve ampoules. NMR samples were prepared
under dinitrogen in 5 mm Wilmad 507-PP tubes fitted
monodentate aryloxide ligands, the TiÄ
appears to be surprisingly long and TiÃ
short. Although it is perhaps not surprising that a longer
TiÄNR distance might be correlated with a shorter TiÃ
/
NAr distance
/OAr rather
/
/
OAr (since both NR and OAr groups are p-donors and
potentially in competition for available dp acceptor
1
with J. Young Teflon valves. H-, 13C{1H}-, and 13C-
orbitals), it is not clear why the TiÄ
/
NAr distance is so
spectra were recorded on Varian Unity Plus 500 and
1
Varian Mercury spectrometers. H and 13C assignments
comparatively long and TiÃOAr so short in 10, espe-
/
cially since most other features of 10 are comparable
with those of 5 and 8. There appear to be no adverse
intra- or inter-molecular contacts.
were confirmed when necessary with the use of nOe,
DEPT-135, DEPT-90, DEPT-45, and two-dimensional
1H-1H and 13C-1H-NMR experiments. All spectra were

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/
Table 1
3.3. [Ti(NtBu){Me3SiNC(Ph)NCH2CH2CH2NMe2}-
˚
Comparison of selected bond distances (A) and angles (8) for
[Ti(Nt Bu){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-C6H3Me2)] (5)
and [Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-
C6H3Me2)] (10)
Ph] (2)
To
Ph)NCH2CH2CH2NMe2}Cl] (0.41 g, 9.50ꢃ
in Et2O (15 ml) at ꢂ80 8C was added a solution of PhLi
(0.10 g, 1.20ꢃ
10ꢂ3 mol) in Et2O (15 ml) dropwise over
a
stirred solution of [Ti(NtBu){Me3SiNC(-
10ꢂ4 mol)
/
5
10
[8]
/
a
/
Bond lengths
Ti(1)Ã
Ti(1)Ã
Ti(1)Ã
Ti(1)Ã
Ti(1)Ã
N(4)Ã
N(1)Ã
O(1)Ã
N(4)Ã
N(3)Ã
/
N(1)
N(2)
N(3)
N(4)
O(1)
1.6991(15)
2.2548(15)
2.1081(15)
2.1531(15)
1.8887(13)
1.336(2)
1.756(2)
2.235(2)
2.084(2)
2.119(2)
1.828(2)
1.319(3)
1.383(3)
1.352(3)
1.730(2)
1.320(3)
[1.713(1)]
[2.223(1)]
[2.080(1)]
[2.124(1)]
15 min. The resulting yellow solution was stirred at
room temperature (r.t.) for 30 min. Volatiles were
removed under reduced pressure and the resulting black
solid was extracted into benzene (20 ml). The black/
brown product was triturated with pentane (30 ml) and
dried in vacuo. Yield: 0.29 g, (68%).
/
/
/
/
[Á]
/
/
CPh
[1.337(2)]
/
C(1)
1.446(2)
[1.377(2)]
/
CAr
1.337(2)
1.7294(15)
1.320(2)
[Á]
/
1H-NMR (C6D6, 300.1 MHz, 293 K): 8.31 (2H, d,
/
Si(1)
[1.734(1)]
3
3Jꢀ
/
6.5 Hz, o-TiPh), 7.46 (1H, t, Jꢀ
/7.6 Hz, p-TiPh),
/
CPh
[1.316(2)]
7.33 (2H, m, m-TiPh), 7.42Á
/
7.06 (5H, overlapping m,
a
Bond angles
N(1)ÃTi(1)Ã
N(1)ÃTi(1)Ã
N(1)ÃTi(1)Ã
N(1)ÃTi(1)Ã
N(2)ÃTi(1)Ã
N(2)ÃTi(1)Ã
N(3)ÃTi(1)Ã
N(3)ÃTi(1)Ã
Ti(1)ÃN(1)Ã
Ti(1)ÃO(1)Ã
Ti(1)ÃN(3)Ã
Ti(1)ÃN(3)Ã
CPhÃN(3)Ã
Ti(1)ÃN(4)Ã
Ti(1)ÃN(4)Ã
Si(1)ÃN(4)Ã
N(4)ÃCPhÃ
PhCN2), 3.05Á2.82 (3H, overlapping m, 2ꢃ
/
/
CN2CH2,
/
/
O(1)
N(2)
N(3)
N(4)
N(3)
N(4)
O(1)
N(4)
C(1)
115.90(7)
100.81(7)
105.61(7)
105.36(7)
81.55(6)
118.75(12)
96.78(9)
113.99(11)
103.5(1)
82.65(8)
144.82(8)
127.17(11)
62.94(9)
174.5(2)
170.3(2)
140.8(5)
92.88(16)
124.3(2)
91.35(16)
134.03(12)
133.3(2)
112.6(2)
[Á]
/
/
/
[98.13(4)]
[110.09(5)]
[104.53(4)]
[83.16(4)]
[144.58(4)]
CH2NMe2), 2.65 (3H, s, NMe), 1.82 (1H, m,
CH2NMe2), 1.68 (3H, s, NMe), 1.41 (9H, s, CMe3),
1.34 (1H, m, CH2CH2CH2), 1.02 (1H, m, CH2CH2CH2),
/
/
/
/
/
/
ꢂ
0.11 (s, 9H, SiMe3). 13C{1H}-NMR (C6D6, 75.0 MHz,
/
/
/
140.02(6)
138.45(6)
62.69(6)
/
/
[Á]
/
293 K): 187.10 (CN2), 175.20 (ipso-TiPh), 137.05 (o-
TiPh), 136.77 (ipso-PhCN2), 128.59, 128.50, 128.43,
127.76, 126.91, 126.53, 126.31 (9C, partially obscured
by solvent, TiPh, PhCN2), 69.23 (CMe3), 61.79
(CH2NMe2), 52.04 (NMe), 47.02 (CN2CH2), 43.71
(NMe), 33.59 (CMe3), 25.82 (CH2CH2CH2), 2.21
(SiMe3). IR (Nujol mull, NaCl plates): 2726 (w),
1944(w), 1578 (w), 1506 (w), 1344 (s), 1299 (m), 1248
(s), 1206 (m), 1153 (w), 1130 (w), 1104 (m), 1061 (m),
1017 (m), 979 (s), 946 (m), 918 (s), 898 (m), 857 (w), 838
(m), 820 (w), 783 (m), 766 (w), 722 (w), 702 (m), 648 (s).
Accurate mass EI-MS for [Ti(NtBu){Me3SiNC-
(Ph)NCH2CH2CH2NMe2}Ph]ꢁ. Found: (Calc. for
/
/
[63.71(4)]
/
/
171.93(13)
167.84(12)
136.65(12)
92.16(11)
124.95(16)
89.8(1)
[178.58(9)]
/
/CAr
[Á]
/
/
/
CH2
CPh
CH2
[138.75(8)]
[92.26(7)]
[125.4(1)]
[89.77(7)]
[129.04(6)]
[131.58(8)]
[113.5(1)]
/
/
/
/
/
/CPh
/
/Si(1)
135.11(8)
132.13(13)
113.22(15)
/
/CAr
/
/
N(3)
For comparison, the corresponding values for previously reported
[11] [Ti(N-2,6-C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}Cl] (8)
are given in brackets.
a
For 5 the generic labels CPh, CAr and CH2 refer to C(16), C(5)
and C(15), respectively in Fig. 1. For 10 CPh, CAr and CH2 refer to
C(20), C(9) and C(19), respectively in Fig. 2.
C25H40N4TiSi): m/zꢀ472.2508 (472.2502). Anal.
/
Found: (Calc. for C25H40N4TiSi): C 60.4 (63.5), H 9.1
(8.5), N 11.7 (11.9)%
referenced internally to residual protio-solvent (1H) or
solvent (13C) resonances and are reported relative to
3.4. [Ti(NtBu){Me3SiNC(Ph)NCH2CH2CH2NMe2}-
tetramethylsilane (dꢀ0 ppm). Chemical shifts are
/
quoted in d (ppm) and coupling constants in hertz.
Infrared spectra were prepared as Nujol mulls between
Me] (3; NMR tube scale synthesis)
A solution of [Ti(NtBu){Me3SiNC(Ph)NCH2CH2-
NaCl plates and were recorded on PerkinÁElmer 1600
/
CH2NMe2}Cl] (6.0 mg, 1.40ꢃ
10ꢂ5 mol) in C6D6 (0.5
ml) in a 5 mm NMR tube was treated with ca. one
/
and 1700 series spectrometers. Infrared data are quoted
in wavenumbers (cmꢂ1). Mass spectra were recorded by
the mass spectrometry service of the University of
Oxford’s Inorganic Chemistry Laboratory. Combustion
analyses were recorded by the analytical services of the
University of Oxford’s Inorganic Chemistry Labora-
tory. Despite repeated recrystallisations, several of the
compounds gave consistently low elemental analyses for
%N and/or %C, consistent with incomplete combustion
(nitride/carbide formation) [21].
1
equivalent of 1.6 M solution of MeLi in Et2O. The H-
NMR spectrum showed formation of 3 as the dominant
product.
1H-NMR (C6D6, 300.2 MHz, 293 K) 7.21Á
/
7.02 (5H,
2.80 (3H, overlapping m,
CN2CH2, CH2NMe2), 2.66 (3H, s, NMe), 2.04Á1.91
(3H, overlapping m, CH2NMe2, 2ꢃCH2CH2CH2), 1.39
(9H, s, CMe3), 0.79 (3H, s, TiMe), 0.22 (9H, s, SiMe3).
overlapping m, PhCN2), 3.03Á
/
2ꢃ
/
/
/

A.C.R. Croft et al. / Journal of Organometallic Chemistry 683 (2003) 120Á
/
130
127
3.5. [Ti(NtBu){Me3SiNC(Ph)NCH2CH2CH2NMe2}-
{N(SiMe3)2}] (4)
NMe), 2.68 (3H, s, C6H3Me2), 2.55 (1H, m, CH2NMe2),
2.13 (3H, s, C6H3Me2), 1.94 (3H, s, NMe), 1.89 (1H, m,
CH2CH2CH2), 1.59 (1H, m, CH2CH2CH2), 1.00 (9H, s,
To
SiN(Ph)NCH2CH2CH2NMe2}Cl] (0.34 g, 7.87ꢃ
mol) in benzene (20 ml), was added a solution of
LiN(SiMe3)2 (0.13 g, 7.87ꢃ
10ꢂ4 mol) in benzene (20
a
stirred solution of [Ti(NtBu){Me3-
10ꢂ4
CMe3), ꢂ
0.38 (9H, s, SiMe3). 13C{1H}-NMR (CD2Cl2,
/
/
125.0, MHz, 233 K): 173.87 (CN2), 160.72 (ipso-
C6H3Me2), 135.93 (ipso-PhCN2), 128.28, 128.19,
127.91, 127.81, 127.50, 127.08, 126.14, 126.08, 125.51
(9C PhCN2 and C6H3Me2), 116.43 (p-C6H3Me2), 68.06
(CMe3), 62.69 (CH2NMe2), 51.65 (NMe), 47.07
(CN2CH2), 43.74 (NMe), 32.59 (CMe3), 25.49
(CH2CH2CH2), 18.21 (C6H3Me2), 17.09 (C6H3Me2),
0.81 (SiMe3). IR (Nujol mull, NaCl plates): 2726 (m),
2684 (w), 2588 (w), 2360 (m), 2342 (m), 2250 (w), 2098
(w), 1942 (w), 1892 (w), 1832 (w), 1804 (w), 1590 (s),
1576 (m), 1506 (s), 1364 (m), 1348 (s), 1294 (s), 1250 (s),
1236 (s), 1208 (m), 1178 (w), 1150 (w), 1128 (w), 1110
(m), 1090 (m), 1062 (m), 1016 (m), 980 (m), 948 (m), 918
(m), 908 (s), 902 (s), 860 (m), 838 (s), 820 (m), 806 (w),
782 (m), 760 (s), 742 (w), 718 (m), 698 (s), 628 (w), 596
(w). Anal. Found: (Calc. for C27H44N4OTiSi): C 62.1
(62.8), H 8.7 (8.6), N 10.4 (10.8)%.
/
ml) dropwise over 20 min. The yellow solution was
heated at 50 8C for 30 h. Volatiles were removed under
reduced pressure and the yellow solid was extracted into
benzene (15 ml). The dark yellow solid was recrystallised
from hexane (30 ml) at ꢂ
/
80 8C and washed with 3ꢃ10
/
ml cold hexane yielding an orange solid which was dried
in vacuo. Yield: 0.13 g (30%).
1H-NMR (C6D6, 300.1 MHz, 293 K): 7.56Á
/
7.01 (5H,
2.79 (3H, overlapping m,
CN2CH2, CH2NMe2), 2.72 (3H, s, NMe), 2.03 (3H,
s, NMe), 1.82 (1H, m, CH2NMe2), 1.31 (9H, s, CMe3),
1.31Á1.22 (2H, overlapping m, CH2CH2CH2), 0.78 (9H,
overlapping m, PhCN2), 2.97Á
/
2ꢃ
/
/
s, N(SiMe3)2), 0.35 (9H, s, N(SiMe3)2), 0.29 (9H, s,
PhCNSiMe3). 13C{1H}-NMR (C6D6, 75.0 MHz, 293
K): 176.36 (CN2), 137.13 (ipso-PhCN2), 129.4, 128.32,
127.67, 126.61 (PhCN2), 69.73 (CMe3), 63.57
(CN2CH2), 54.66 (NMe), 48.01 (CH2NMe2), 47.11
(NMe), 33.21 (CMe3), 25.52 (CH2CH2CH2), 8.22
(N(SiMe3)2), 1.36 (overlapping N(SiMe3)2 and
PhCNSiMe3). IR (Nujol mull, NaCl plates): 4331 (m),
4257 (m), 3061 (m), 2786 (s), 2765 (m), 2723 (m), 2680
(m), 2361 (w), 2342 (w), 2206 (w), 2132 (w), 2092 (w),
1947 (w), 1884 (w), 1808 (w), 1636 (m), 1603 (m), 1577
(s), 1509 (s), 1485 (s), 1456 (s), 1365 (s), 1347 (m), 1311
(s), 1300 (m), 1260 (m), 1245 (s), 1205 (s), 1153 (s), 1099
(w), 1062 (w), 1017 (m), 983 (m), 932 (s), 920 (m), 901
(s0, 868 (s), 839 (s), 803 (s), 785 (s), 760 (m), 722 (s), 672
(m). Anal. Found: (Calc. for C25H53N5TiSi3): C 49.2
(54.0), H 8.9 (9.6), N 10.0 (12.6)%.
3.7. [Ti(NtBu){Me3SiNC(Ph)NCH2CH2NMe2}(O-
2,6-C6H3Me2)] (7)
To
SiNC(Ph)NCH2CH2NMe2}Cl] (0.41 g, 8.8ꢃ
mol) in toluene (15 ml) was added a solution of LiO-
2,6-C6H3Me2 (0.14 g, 8.8ꢃ
10ꢂ4 mol) in toluene (30 ml)
a
stirred solution of [Ti(NtBu){Me3-
10ꢂ4
/
/
dropwise over 15 min. The yellow solution was stirred at
r.t. for 16 h. Volatiles were removed under reduced
pressure, and the resulting orangeÁ
extracted into benzene (30 ml). The yellow solid was
recrystallised from hexane (25 ml) at ꢂ80 8C and
washed with 5ꢃ10 ml cold hexane. Yield: 0.11 g (25%).
1H-NMR (C6D6, 500.0 MHz, 293 K): 7.23Á
7.19 (4H,
overlapping m, PhCN2 and m-C6H3Me2), 7.04Á7.03
(3H, overlapping m, PhCN2 and m-C6H3Me2), 6.88
/
brown solid was
/
/
/
/
3.6. [Ti(NtBu){Me3SiNC(Ph)NCH2CH2CH2NMe2}-
(O-2,6-C6H3Me2)] (5)
2
(1H, t, Jꢀ7.3 Hz, p-C6H3Me2), 3.25 (1H, overlapping
/
m, CN2CH2), 2.70 (1H, overlapping m, CN2CH2), 2.62
(3H, s, NMe), 2.61 (6H, s, C6H3Me2), 2.12 (1H, m,
CH2NMe2), 1.80 (3H, s, NMe), 1.77 (1H, m,
CH2NMe2), 1.32 (s, 9H,CMe3), 0.14 (s, 9H, SiMe3).
13C{1H}-NMR (C6D6, 125.0 MHz, 293 K): 174.06
(CN2), 161.70 (ipso-C6H3Me2), 136.03 (ipso-PhCN2),
129.68, 128.52, 12.50, 127.68, 126.54 (PhCN2 and
C6H3Me2), 118.25 (p-C6H3Me2), 68.39 (CMe3), 63.11
(CN2CH2), 49.49 (NMe), 46.88 (CH2NMe2), 45.20
(NMe), 33.57 (CMe3), 18.50 (C6H3Me2), 2.32 (SiMe3).
IR (Nujol mull, NaCl plates): 4331 (m), 4258 (m), 4065
(w), 2727 (m), 2361 (m), 2342 (w), 1950 (w), 1889 (w),
1828 (w), 1771 (w), 1592(m), 1505 (m) 1405 (m), 1349
(s), 1330(m), 1290 (m), 1262 (m), 1249 (s), 1232 (s), 1207
(m), 1159 (w), 1126(m), 1090 (s), 1063 (w), 1025 (s), 947
(m), 934 (m), 919 (m), 892 (s), 868 (s), 840 (s), 820 (m),
805 (m), 759 (s), 740 (w0, 723 (m), 703 (m), 669 (w), 629
To
SiNC(Ph)NCH2CH2CH2NMe2}Cl] (0.55 g, 1.29ꢃ
10ꢂ3 mol) in toluene (20 ml), was added a solution of
LiO-2,6-C6H3Me2 (0.16 g, 1.29ꢃ
10ꢂ3 mol) in toluene
(40 ml) dropwise over 15 min. The resulting yellow
solution was stirred at r.t. for 2 h. Volatiles were
removed under reduced pressure, and the resultant
yellow solid was extracted into hexane (50 ml). The
a
stirred solution of [Ti(NtBu){Me3-
/
/
yellow solid was recrystallised from hexane (20 ml) at ꢂ
/
80 8C, washed with 5ꢃ
vacuo. Yield: 0.41 g (63%).
1H-NMR (CD2Cl2, 500.0 MHz, 233 K): 7.50Á
/
10-ml cold hexane and dried in
/
7.29
(5H, overlapping m, PhCN2), 7.03 (1H, d, Jꢀ
/
7.08 Hz,
2
m-C6H3Me2), 6.93 (1H, d, Jꢀ
/
6.51 Hz, m-C6H3Me2),
6.57 (1H, m, p-C6H3Me2), 3.63 (1H, m, CH2NMe2),
3.38Á3.24 (2H, overlapping m, CN2CH2), 2.87 (3H, s,
/

128
A.C.R. Croft et al. / Journal of Organometallic Chemistry 683 (2003) 120Á
/
130
2
(w). Anal. Found: (Calc. for C26H45N4TiOSi): C 58.2
(61.8), H 8.4 (9.0), N 9.6 (11.1)%.
6.74 (1H, t, Jꢀ
/
7.32 Hz, p-O-2,6-C6H3Me2), 3.12 (1H,
m, CN2CH2), 2.95 (1H, m, CN2CH2), 2.86 (1H, m,
CH2NMe2), 2.80 (6H, s, N-2,6-C6H3Me2), 2.51 (6H, s,
O-2,6-C6H3Me2), 2.50 (3H, s, NMe), 1.76 (3H, s, NMe),
1.71 (1H, m, CH2NMe2), 1.25 (1H, m, CH2CH2CH2),
3.8. [Ti(N-2,6-
C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}Me)]
(9)
1.04 (1H, m, CH2CH2CH2), ꢂ0.08 (9H, s, SiMe3).
/
13C{1H}-NMR (C6D6, 125.0 MHz, 293 K): 175.93
(CN2), 162.37 (ipso N-2,6-C6H3Me2), 159.83 (ipso O-
2,6-C6H3Me2), 135.96 (ipso PhCN2), 132.24 (o-O-2,6-
C6H3Me2), 129.10, 128.75, 128.61, 128.53, 127.48,
126.76, 126.41 (overlapping m-O-2,6-C6H3Me2, m-N-
2,6-C6H3Me2, o-N-2,6-C6H3Me2, PhCN2), 119.56 (p-O-
2,6-C6H3Me2), 119.03 (p-N-2,6-C6H3Me2), 61.97
(CH2NMe2), 52.06 (NMe), 45.89 (CH2CN2), 45.74
(NMe), 25.40 (CH2CH2CH2), 20.44 (N-2,6-C6H3Me2),
18.13 (O-2,6-C6H3Me2), 1.68 (SiMe3). IR (Nujol mull,
NaCl plates) 2722 (w), 2678 (w), 2356 (w), 2340 (w),
1888 (w), 1732 (w), 1590 (m), 1344 (m), 1312 (m), 1276
(s), 1236 (s), 1208 (m), 1178 (w), 1152 (w), 1110 (m),
1092 (s), 1060 (m), 1026 (w), 1012 (m), 980 (s), 948 (w),
896 (s), 854 (m), 838 (m), 818 (w), 784 (m), 756 (s), 740
To a stirred solution of [Ti(N-2,6-C6H3Me2){Me3-
SiN(Ph)NCH2CH2CH2NMe2}Cl] (0.36 g, 7.57ꢃ
mol) in Et2O (40 ml) at ꢂ80 8C was added 1.6M MeLi/
Et2O solution (0.47 ml, 7.57ꢃ
10ꢂ4 mol) over 15 min.
The resulting orange solution was stirred at ꢂ80 8C for
/
10ꢂ4
/
/
/
15 min before being allowed to warm to r.t. over 20 min.
Volatiles were removed under reduced pressure, and the
resulting brown solid extracted into benzene (25 ml).
The resulting solid was triturated with pentane (25 ml)
to give a brown solid. Yield: 0.17 g (50%).
1H-NMR (C6D6, 300.0 MHz, 293 K): 7.21Á
overlapping m, C6H3Me2, PhCN2), 6.80 (1H, t, Jꢀ
7.32 Hz, p-C6H3Me2), 2.87 (6H, s, C6H3Me2), 2.85Á
2.73 (2H, overlapping m, 2ꢃCN2CH2), 2.33 (3H, s,
NMe), 2.32 (1H, m, CH2NMe2), 2.01 (3H, s, NMe), 1.82
(1H, m, CH2NMe2), 1.31Á1.09 (2H, overlapping m, 2ꢃ
/
7.06 (7H,
2
/
/
/
/
/
Table 2
X-ray data collection and processing parameters for [Ti(Nt Bu){Me3-
SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-C6H3Me2)] (5) and [Ti(N-2,6-
CH2CH2CH2), 0.95 (3H, s, TiMe), 0.11 (9H, s, SiMe3).
13C-NMR (C6D6, 75.0, MHz, 293 K): 177.55 (CN2),
159.66 (ipso-C6H3Me2), 136.25 (ipso-PhCN2), 132.09
(C6H3Me2), 129.01, 128.63, 128.29, 127.80 (PhCN2),
127.47 (C6H3Me2), 119.14 (p-C6H3Me2), 61.18
(CH2NMe2), 50.54 (NMe), 46.88 (NMe), 45.76
(CN2CH2), 38.20 (TiMe), 20.20 (C6H3Me2), 1.96
(SiMe3). IR (Nujol mull, NaCl plates): 4330 (m), 4257
(m), 2726 (m), 1588 (m), 1505 (m), 1345 (m), 1316 (s),
1262 (m), 1247 (m), 1226 (w), 1205 (w), 1173 (m), 1153
(m), 1093 (s), 1063 (s), 1016 (m), 981 (w), 949 (w), 918
(m), 897 (s), 839 (m), 820 (s), 785 (m), 756 (s), 741 (w),
723 (m), 701 (m). Anal. Found: (Calc. for
C24H38N4TiSi): C 61.3 (62.8), H 8.9 (8.4), 11.9 (12.2)%.
C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-2,6-C6H3Me2)]×
/
0.5(C6H14) (10×0.5(C6H14))
/
5
10×
/
0.5(C6H14)
Molecular formula
C
27H44N4OsiTi C31H44N4OSiTi×
/
0.5(C6H14
)
Formula weight
Crystal system
Space group
516.66
Monoclinic
P21/c
607.80
Monoclinic
P21/n
Unit cell dimensions
˚
a (A)
˚
10.4590(2)
15.8439(3)
18.0981(4)
97.3378(7)
2974.5
12.7710(2)
19.5990(3)
14.4818(3)
99.2435(7)
3577.7
b (A)
˚
c (A)
a (o)
3
V (A )
˚
3.9. [Ti(N-2,6-
C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-
2,6-C6H3Me2)] (10)
Z
4
0.352
4
0.302
Absorption coefficient
)
(mmꢂ1
Crystal description
Pale yellow
block
Orange fragment
0.06ꢃ0.12ꢃ0.34
To a stirred solution of [Ti(N-2,6-C6H3Me2){Me3-
Crystal size (mm)
0.20ꢃ
/
0.28ꢃ
/
/
/
SiN(Ph)NCH2CH2CH2NMe2}Cl] (0.56 g, 1.17ꢃ
mol) in toluene (30 ml) was added a solution of LiO-2,6-
C6H3Me2 (0.15 g, 1.17ꢃ
10Á3 mol) in toluene (30 ml)
/
10ꢂ3
0.32
Reflections collected
Unique reflections
Rint
26 442
7024
0.048
4606
41 144
8147
0.043
/
dropwise over 15 min. The red brown solution became
orange in colour and was stirred at r.t. for 16 h. Volatiles
were removed under reduced pressure, and the resulting
Observed reflections
Absorption correction
Tmin, Tmax
4733 [I ꢀ3s(I)]
/
Semi-empirical
0.89, 0.93
307
Semi-empirical
0.90, 0.98
388
orangeÁ
The orange solid was recrystallised from hexane (15 ml)
at ꢂ80 8C and washed with 4ꢃ10 ml cold hexane.
Yield: 0.10 g (63%).
1H-NMR (C6D6, 500.0 MHz, 293 K): 7.26Á
overlapping m, m-N-2,6-C6H3Me2 m-O-2,6-C6H3Me2,
/brown solid was extracted into hexane (50 ml).
Number of parameters
refined
Final R indices a
R1ꢀ
wRꢀ
0.27, 0.31
/
0.0364
R1ꢀ/0.0507
/
/
/0.0407
wRꢀ/0.0645
Largest residual Dr
ꢂ
/
ꢂ
/
0.30 and 0.43
/7.05 (9H,
ꢂ3
˚
features (e A
)
2
a
2
Rꢀ
/
ajjFojꢂ
/
jFcjj/ajFoj; Rwꢀ
/
v{aw(jFojꢂ
/
jFcj)2/awjFoj }.
PhCN2), 6.86 (1H, t, Jꢀ7.32 Hz, p-N-2,6-C6H3Me2),
/

A.C.R. Croft et al. / Journal of Organometallic Chemistry 683 (2003) 120Á
/
130
129
(m), 722 (m), 626 (w), 566 (m). Anal. Found: (Calc. for
C31H44N4OTiSi): C 63.6 (65.9), H 8.2 (7.8), N 9.5
(9.9)%.
No. 206511 for compound 10. Copies of this informa-
tion may be obtained free of charge from The Director,
CCDC, 12, Union Road, Cambridge CB2 1EZ, UK
(Fax: ꢁ44-1223-336033; e-mail: deposit@ccdc.cam.a-
/
3.10. Crystal structure determination of
c.uk or http://www.ccdc.cam.ac.uk).
[Ti(NtBu){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-
2,6-C6H3Me2)] (5) and [Ti(N-2,6-
C6H3Me2){Me3SiNC(Ph)NCH2CH2CH2NMe2}(O-
Acknowledgements
2,6-C6H3Me2)]×
/
0.5(C6H14) (10×/0.5(C6H14))
We thank the EPSRC for support.
Crystal data collection and processing parameters are
given in Table 2. Crystals were mounted on a glass fibre
using perfluoropolyether oil and cooled rapidly to 150 K
in a stream of cold N2 using an Oxford Cryosystems
CRYOSTREAM unit. Diffraction data were measured
References
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/
Nonius KappaCCD diffractometer
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/
Ka radiation, lꢀ
/
˚
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/
[2] See the following and references therein: (a) P. Mountford, Chem.
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preliminary non-H atom structure showed a number of
relatively large peaks of electron density. Some of these
were assigned as a hexane molecule disordered over two
orientations related by a crystallographic centre of
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¨
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were refined for the hexane, with CÃ
restrained to 1.54(2) A and CÃ
/C bond lengths
˚
/
CÃ/C bond angles
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the major positions of the disordered ligand C atoms,
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3616.
˚
in the N2Ti plane were restrained to be within 0.01 A of
their common mean; related bond angles were restrained
to be within 18 of their common mean.
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4. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC, No. 206510 for compound 5 and
are drawn ‘Tiꢀ
/
NR’, the formal titaniumÁimido nitrogen bond
/
order in the complexes described herein is probably best thought
of as closer to three (pseudo-s2 p4; triple bond) rather than as

130
A.C.R. Croft et al. / Journal of Organometallic Chemistry 683 (2003) 120Á130
/
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