Amido- and imido-ethylpyridine titanium complexes. Crystal structure of {Ti[NCH2CH2py]Cl2(THF)}2

Article abstract of DOI:10.1016/S0022-328X(01)00837-3

Compounds of general formula N(R₁)(R₂)CH₂CH₂py (py=C₅H₄N; R₁=R₂=SiMe₃, 1a; R₁=H, R₂=Si^tBuMe₂, 1b; R₁=SiMe₃, R₂=Si^tBuMe₂, 1c; R₁=SiMe₃, R₂=Ph, 5) were synthesised. They readily reacted with TiCl₄ to afford the corresponding amidoaminotrichlorides {Ti[N(R₂)(CH₂CH₂py)]Cl₃} (R₂=SiMe₃, 2a; R₂=Si^tBuMe₂, 2b; R₂=Ph, 6). The related imido derivatives {Ti[N(CH₂CH₂py)]Cl₂}_n (3b) and {Ti[N(CH₂CH₂py)](L)Cl₂}₂ (L=THF, 3c; PMe₃, 3d) were isolated upon heating and reaction with L, respectively. Reaction of 6 with THF afforded the corresponding adduct, {Ti[N(Ph)(CH₂CH₂py)](THF)Cl₃} (7). Compound 3b reacted with LiNMe₂ to give asymmetrical {Ti₂[N(CH₂CH₂py)][N(CH₂CH ₂py)]′Cl₄} (4a). Compound {CpTi[N(CH₂CH₂py)]Cl}_n (4b), was formed when 3b reacted with NaCp. Analogous studies with 2a and 6 led to Cp₂TiCl₂. {Cp₂Ti₂[μ-N(Ph)]Cl₂} (8) was isolated as the product of CpTiCl₃ and Na[N(Ph)CH₂CH₂py]. The molecular structure of 3c was determined by X-ray single crystal diffraction.

Full text of DOI:10.1016/S0022-328X(01)00837-3

Journal of Organometallic Chemistry 632 (2001) 17–26
www.elsevier.com/locate/jorganchem
Amido- and imido-ethylpyridine titanium complexes. Crystal
structure of {Ti[NCH2CH2py]Cl2(THF)}2
Jose´ R. Ascenso, Cristina G. de Azevedo, Alberto R. Dias, M. Teresa Duarte,
Ineˆs Eleute´rio, Maria Joa˜o Ferreira, Pedro T. Gomes, Ana M. Martins *
Centro de Qu´ımica Estrutural, Complexo I, Instituto Superior Te´cnico, A6. Ro6isco Pais, 1, 1049-001 Lisbon, Portugal
Received 16 February 2001; accepted 29 March 2001
Abstract
Compounds of general formula N(R1)(R2)CH2CH2py (py=C5H4N; R1=R2=SiMe3, 1a; R1=H, R2=SitBuMe2, 1b; R1=
SiMe3, R2=SitBuMe2, 1c; R1=SiMe3, R2=Ph, 5) were synthesised. They readily reacted with TiCl4 to afford the corresponding
amidoaminotrichlorides {Ti[N(R2)(CH2CH2py)]Cl3} (R2=SiMe3, 2a; R2=SitBuMe2, 2b; R2=Ph, 6). The related imido deriva-
tives {Ti[N(CH2CH2py)]Cl2}n (3b) and {Ti[N(CH2CH2py)](L)Cl2}2 (L=THF, 3c; PMe3, 3d) were isolated upon heating and
reaction with L, respectively. Reaction of 6 with THF afforded the corresponding adduct, {Ti[N(Ph)(CH2CH2py)](THF)Cl3} (7).
Compound 3b reacted with LiNMe2 to give asymmetrical {Ti2[N(CH2CH2py)][N(CH2CH2py)]%Cl4} (4a). Compound
{CpTi[N(CH2CH2py)]Cl}n (4b), was formed when 3b reacted with NaCp. Analogous studies with 2a and 6 led to Cp2TiCl2.
{Cp2Ti2[m-N(Ph)]Cl2} (8) was isolated as the product of CpTiCl3 and Na[N(Ph)CH2CH2py]. The molecular structure of 3c was
determined by X-ray single crystal diffraction. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Titanium; Amido; Imido; 2%-Aminoethyl-2-pyridyl derivatives
1. Introduction
The particular features that dictate the performance
of polyfunctional nitrogen compounds as catalysts are
still not fully understood [10,19]. Thus, the study of
Group 4 complexes with ancillary N-donor ligands is a
topic of current interest [20–24]. We report the synthe-
sis, characterisation and reactivity of new Ti(IV) com-
plexes containing amido- and imido-ethylpyridine
ligands.
Nitrogen-based ligands offer a great diversity of
structural frameworks that have been used as ancillary
ligands in several studies of organometallic chemistry
[1–7], including Group 4 metal complexes with activity
in olefin polymerisation [8–11]. Relevant results include
bis(amido)titanium (IV) complexes that carry out the
living polymerisation of olefins [12–14].
The amido/amine donor set has attracted the interest
of several researchers. Pyridyl-substituted 1-azaallyl lig-
ands have been successfully co-ordinated to zirconium
to give octahedral complexes that show high activity in
ethylene polymerisation [15,16]. Recent studies on
Group 4 aminopyridinato complexes emphasise the im-
portance of the amido nitrogen substituents on the
control of metal–ligand stoichiometry and reactivity
[5,15,17,18].
2. Results and discussion
Silylated amine derivatives are useful reagents as they
are easy to synthesise and because they react with metal
chlorides to give R3SiCl which, being volatile, are easily
eliminated from the reaction media. These features,
associated with efficient steric bulk, partially explain
their extensive use in synthesis and the large number of
co-ordination compounds containing such ligands
[1,5,9,25,26]. Silylated derivatives of 2%-aminoethyl-2-
pyridine are no exception. Compounds 1a–1c were
isolated in good yields (\90%) and in multigram
* Corresponding author. Tel.: +351-218419284; fax: +351-
218464457.
E-mail address: ana.martins@ist.utl.pt (A.M. Martins).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00837-3

18
J.R. Ascenso et al. / Journal of Organometallic Chemistry 632 (2001) 17–26
Scheme 1. (i) SiMe3Cl; (ii) SitBuMe2Cl; (iii) CF3SO3SiMe3; (iv) TiCl4; (v) TiCl4.
quantities (Scheme 1). 1a was obtained as a colourless
oil from the reaction of 2%-aminoethyl-2-pyridine with
three equivalents of SiMe3Cl in dichloromethane. The
reaction of primary amines with Me3SiCl usually gives
monosilylated products. The synthesis of bis-silylated
compounds often requires the use of strong elec-
trophiles or catalysts [27]. The mild experimental condi-
tions used in the preparation of 1a suggest the
assistance of the pyridyl fragment in NꢀH intramolecu-
lar bond activation of the N(H)(SiMe3)CH2CH2py in-
termediate. In similar conditions, the use of a bulky
reagent (SitBu(Me)2Cl) led to a pale-yellow oil, N(H)-
(SitBuMe2)CH2CH2py (1b) that was converted by
CF3SO3SiMe3 to the bis-silylated compound N(SiMe3)-
(SitBuMe2)CH2CH2py (1c).
Compounds 1a and 1c readily react with TiCl4, in
toluene, to afford the expected trichlorides, {Ti[N-
(SiMe3)CH2CH2py]Cl3} (2a) and {Ti[N(SitBuMe2)-
CH2CH2py]Cl3} (2b) as dark-orange and bright-red
microcrystalline solids, respectively, which precipitate
out of solution in essentially quantitative yields
(Scheme 1). The use of SiMe3Cl as a leaving group
proved to be the best way to carry out these reactions.
Attempts to use monosilylated compounds in the pres-
ence of a base to neutralise the HCl formed, or the
more common procedures involving lithium or sodium
salts [5,26], led to mixtures of unidentified products.
The outcome of the reactions also depends on the
solvent used. When carried out in dichloromethane, 1H-
and 13C-NMR spectra show the formation of 2a and
ethylpyridine (3:1), which is assumed to be co-ordinated
to the metal centre in view of the low field shifted
resonances of the ortho-pyridyl (l 8.92) and CH2
aliphatic protons (l 4.99). The 1H-NMR spectra of
both compounds attest the chelating co-ordination of
the ligands to the titanium since all the proton reso-
nances are shifted low field in relation to the corre-
sponding values in the ligand precursors. Particularly
sensitive to the metal co-ordination are the a-nitrogen
chain protons (l 3.17, 1a vs. 4.63 2a; 3.22, 1c vs. 4.74,
2b) and the ortho-pyridyl protons (l 8.52, 1a vs. 8.75
2a; 8.52, 1c vs. 8.71, 2b). The chain carbons adjacent to
the pyridyl are slightly shielded (l 44.8, 1a vs. 39.0 2a
and 44.4, 1c vs. 40.0, 2b). The very low solubilities of 2a
and 2b in non-co-ordinating solvents make their formu-
lation most probably as dimers or other higher-order
aggregates [24,28]. Unfortunately, the poor-quality
crystals grown in dichloromethane prevented the obten-
tion of their molecular solid state structures. Also, all
the attempts to obtain mass spectra (EI and FAB) were
unfruitful.
Compounds 2a and 2b proved to be unstable under a
variety of conditions (Scheme 2). In order to increase
their solubility, attempts were made to introduce a
second ligand into the metal co-ordination sphere. No
reaction was observed, however, when 2a was mixed
with one equivalent of N(SiMe3)2CH2CH2py (1a). The
reaction of 2a with NaCp gave a mixture of compounds
(as shown later). These results are probably due to the
lability of the NꢀSi bond, a fact well illustrated by the
formation of compounds 3b–3d.
In the presence of L-type donors (THF and PMe3),
or upon heating in 1,2-dichloroethane, N-bridging
imides are formed as a result of NꢀSi bond cleavage.
The dissolution of 2a, 2b in THF affords {Ti2[m-
NCH2CH2py]2Cl4(THF)2} (3c) as a bright-red crys-
talline material in quantitative yield. Suitable X-ray
crystals were thus obtained from the reaction media.
Fig. 1 depicts the molecular structure of 3c. Selected
bond lengths and angles are presented in Table 1.
The molecule is a dimer, with two titanium centres
linked by N-imido bridges and related by a centre of
symmetry lying in the plane defined by the Ti2N2 ring.
Each titanium atom is located in a distorted octahedral
environment, with angles ranging from 82.02(10) to
97.10(13)°. The N(1)ꢀCl(1)ꢀN(2)ꢀN(1A) atoms are al-
,
most co-planar, (maximum deviation, 0.0021 A), with
,
the titanium atom 0.118(2) A away from this plane, in
the direction of the axial chloride. The nitrogen atoms
of the pyridyl-imido ligand occupy equatorial positions,
with each N-imido co-ordinated trans to the N-pyridyl
atom of the other ligand. The THF group occupies an
axial position and thus both chloride atoms are cis to
,
each other. The Ti···Ti distance (2.848(2) A) falls in the

J.R. Ascenso et al. / Journal of Organometallic Chemistry 632 (2001) 17–26
19
Scheme 2. (i) NaCp; (ii) 1,2-dichloroethane, D; (iii) THF; (iv) THF; (v) PMe3; (vi) LiNMe2; (vii) NaCp.
usual range for this type of binuclear Ti(IV) complexes
[29–32]. The four-membered ring is rather planar with
different TiꢀN bonding distances (Ti(1)ꢀN(1)=
,
1.932(4), Ti(1)ꢀN(1A)=1.868(4) A), which are within
the values usually found for TiꢀN bridging imido com-
,
plexes (1.86–2.17 A) [30,33,34]. For complexes contain-
ing chelating m-N-imido ligands, the stereochemical
constraint imposed by the chelating ligand can induce
considerable lengthening of the TiꢀN bonds (2.04–2.17
,
A) [33]. This increase is not observed for 3c, where the
chelating effect is reflected in the enlargement of the
aliphatic chain bond angles (N(1)ꢀC(1)ꢀC(2) (112.5(5)°)
and C(1)ꢀC(2)ꢀC(3) (115.1(5)°)). The small distortion
observed for the Ti2N2 core, with a difference of 0.064
,
A between the Ti(1)ꢀN(1) and Ti(1)ꢀN(1A) distances, is
comparable to that reported for other compounds con-
taining m-N-imido ligands and a centre of inversion
[30,34]. As expected on the basis of the trans effect
associated to imido ligands, the equatorial Ti(1)ꢀCl(1)
,
bond (2.4074(16) A) is longer than the axial Ti(1)ꢀCl(2)
,
distance (2.3271(18) A). The same effect may be respon-
,
sible for the value of 2.304(4) A for the Ti(1)ꢀN(2)
bond, that is slightly higher than the mean distance
Fig. 1. ORTEP diagram of 3c showing thermal ellipsoids at 40%
probability level. Hydrogens are omitted for clarity.
,
reported for the Tiꢀpyridine bond (2.279 A) [35].

20
J.R. Ascenso et al. / Journal of Organometallic Chemistry 632 (2001) 17–26
Table 1
of resonances are observed for both pyridyl protons
,
Bond lengths (A) and angles (°) for 3c
(e.g. l 9.45 H6 and 8.27 H%) and aliphatic chains (l
6
2.33, 2.93, 4.99, 5.78 and 2.77, 3.48, 4.72, 5.41). The
diastereotopic pattern displayed by the methylenic
chain protons indicates co-ordination of both imido
and pyridyl moieties. Similarly, there are two sets of
signals in the 13C-NMR spectrum. Two-dimensional
(2D) NMR experiments, 1H{1H} 2D correlations
(COSY, NOESY and TOCSY) and 13C{1H} single
bond correlation (HETCOR) allowed the assignment of
all the resonances. Variable-temperature NMR experi-
ments showed no ligand exchange in the range −50 to
+60°C. The NMR is consistent with the formulation
of 4a as a dimer with two bridging N-imido ligands
between the titanium atoms. The structure has no in-
version centre, suggesting that the two ligands are
arranged differently around the Ti2N2 core. As repre-
sented in Scheme 2, one of the pyridyl fragments co-or-
dinates in the Ti2N2 plane while the other occupies a
position out of this plane. Two different co-ordination
geometries may be envisaged for the titanium atoms,
namely trigonal-bipyramidal or quadrangular-pyrami-
dal. Although our results do not allow an unequivocal
assignment, the lack of reported X-ray characterised
trigonal-bipyramidal structures for Ti(IV) m-imido com-
plexes makes the quadrangular pyramidal arrangement
more probable [33,34,36]. The limited stability of com-
plex 4a in toluene and THF (observed after 2 days,
even at −20°C) prevented its characterisation by X-ray
diffraction studies.
,
Bond lengths (A)
Bond angles (°)
Ti(1)ꢀN(1)
Ti(1)ꢀO(1)
Ti(1)ꢀCl(2)
Ti(1)ꢀTi(1A)
N(1)ꢀTi(1A)
C(2)ꢀC(1)
Ti(1)ꢀN(2A)
Ti(1)ꢀCl(1)
N(1)ꢀC(1)
1.868(4)
2.167(4)
2.3271(18)
2.848(2)
1.932(4)
1.534(7)
2.304(4)
2.4074(16)
1.462(6)
1.486(7)
2.304(4)
N(1)ꢀTi(1)ꢀCl(2)
O(1)ꢀTi(1)ꢀCl(2)
N(1)ꢀTi(1)ꢀCl(1)
O(1)ꢀTi(1)ꢀCl(1)
Cl(2)ꢀTi(1)ꢀCl(1)
C(1)ꢀN(1)ꢀTi(1)
Ti(1)ꢀN(1)ꢀTi(1A) 97.07(18)
N(1)ꢀC(1)ꢀC(2)
N(2)ꢀC(3)ꢀC(2)
100.79(14)
162.40(11)
97.10(13)
82.02(10)
89.08(6)
133.2(3)
112.7(5)
118.8(5)
C(2)ꢀC(3)
N(2)ꢀTi(1A)
C(3)ꢀN(2)ꢀTi(1A) 122.9(3)
N(1)ꢀTi(1)ꢀN(1A)
N(1A)ꢀTi(1)ꢀO(1)
N(1A)ꢀTi(1)
82.93(18)
91.64(15)
85.93(16)
ꢀN(2A)
(A) Generated by symmetry operation −x+1, −y+1, −z+2.
A similar 14-electron structure is assumed for {Ti2[m-
NCH2CH2py]2Cl4(PMe3)2} (3d) that precipitated out of
toluene as a yellow microcrystalline solid as the reac-
tion of the in situ generated 2b and PMe3 proceeded.
When heated in 1,2-dichloroethane, 2a afforded
quantitatively a red microcrystalline solid, which analy-
ses for TiC7H8N2Cl2. In the absence of an L-donor
ligand, we propose that the imido-bridged core is main-
tained (that is, after all, the most common arrangement
in this type of compounds [29,33,34,36,37]). The 14-
electron titanium centres may be achieved by chloride
bridges, leading to the polymeric structure proposed
above for 3b. Similar linkages have been reported for
[Ti(m-NSiMe3)Cl2]8 [37].
Attempts to increase the stability of the amido com-
plexes led us to the replacement of the silyl group by
phenyl (Scheme 3).
In order to get some insight into the structure of 3b,
several attempts were made to replace one chloride by a
bulkier ligand, as represented in Scheme 2. Efforts to
introduce an alkyl group (Me or CH2Ph) in the tita-
nium co-ordination sphere were unsuccessful, leading to
unidentified products. Treatment of 3b with one equiva-
lent of NaCp afforded a brown microcrystalline sample
of 4b in poor yield (B5%). This compound analysed
for {CpTi[NCH2CH2py]Cl} and showed in its mass
spectrum a parent ion corresponding to a tetramer (i.e.
{CpTi[NCH2CH2py]Cl}4), reflecting the trend of these
compounds to form higher-order aggregates, possibly
to cope with the acidic titanium centres. A similar
reaction with 3c did not allow the isolation of well-
defined compounds. The reaction of equimolar
amounts of LiNMe2 and 3b, in toluene, did not afford
the desired substitution compound, {Ti[NCH2CH2py]-
(NMe2)Cl}. Instead, it appears to have broken the
polymeric structure of 3b leading to a dark-red solid 4a,
Compound N(SiMe3)(C6H5)CH2CH2py (5) was ob-
tained in good yield (94%) as an orange oil, when the in
situ generated lithium salt of 2%-(N-phenylamino)ethyl-
2-pyridine reacted with SiMe3Cl in n-hexane. The
equimolar reaction of compound 5 with TiCl4 proceeds
similarly as for 1a or 1c to afford {Ti[N(Ph)-
CH2CH2py]Cl3} (6) in quantitative yield. As previously
observed, the a-nitrogen chain protons are deshielded
upon co-ordination (l 3.81, 5 vs. 4.80, 6), as well as the
ortho-pyridyl proton (l 8.59, 5 vs. 8.90, 6). As expected,
6 is more robust than its silylated analogues, since no
ligand cleavage is observed in the presence of THF. In
fact, dissolution of 6 in THF gave the corresponding
adduct, {Ti[N(Ph)CH2CH2py]Cl3(THF)} (7), in quanti-
tative yield. The introduction of THF in the metal
co-ordination sphere does not induce significant
1
changes in the H- and 13C-NMR resonances.
Our studies pursued the synthesis of mixed cyclopen-
tadienyl-amidoamino complexes of general formula
{CpTi[N(R)CH2CH2py]Cl2}. With this aim in mind,
{Ti[N(SiMe3)CH2CH2py]Cl3} (2a) was allowed to react
with one equivalent of NaCp in THF to give a dark-red
1
in ca. 27% reproducible yield. The H-NMR spectrum
at room temperature shows a total absence of NMe2
groups and two inequivalent ligands, with different
signals for the pyridyl and the chain protons. Two sets

J.R. Ascenso et al. / Journal of Organometallic Chemistry 632 (2001) 17–26
21
Scheme 3. (i) 1-nLiBu, 2-SiMe3Cl; (ii) TiCl4; (iii) THF; (iv) 1-NaH, 2-CpTiCl3.
material soluble in toluene. The NMR data suggests the
presence of the desired product {CpTi[N(SiMe3)-
CH2CH2py]Cl2} (3a) as the major component, as evi-
denced by the signals at l 6.19 (Cp), 8.44 (Py H6), 4.58
and 3.14 (CH2N and CH2py, respectively) and 0.24
(SiMe3). The simultaneous formation of Cp2TiCl2 (yield
B5%) was inferred by the resonance at l 5.91. Unfor-
tunately the compound resisted all recrystallisation at-
tempts, leading to a mixture of insoluble materials. The
analogous reaction of equimolar amounts of 6 and
NaCp gave Cp2TiCl2, in very low yield, as the only
identified product. A different approach was attempted
when CpTiCl3 was mixed with N(SiMe3)2CH2CH2py
(1a). No reaction was observed, however. The reaction
of CpTiCl3 with the sodium salt of of 2%-(N-pheny-
lamino)ethyl-2-pyridine led to ligand cleavage and af-
forded the already known complex {Cp2Ti2[m-N-
(Ph)]Cl2} (8) [30,38], in poor yield (B10%), according
to Scheme 3. This was confirmed by the re-determina-
tion of its molecular structure by X-ray diffraction of
crystals grown from diethylether.1
in the literature for strongly acidic metal centres [41–
43]. The greater stability of bis-Cp titanium complexes
when compared to their Cp-amido analogues is proba-
bly a considerable driving force for the observed out-
come of these reactions.
3. Conclusions
N(SiMe3)(R)(CH2CH2)py reacts readily with TiCl4 to
give the corresponding trichlorides, {Ti[N(R)-
(CH2CH2)py]Cl3}. The study of their chemistry is ham-
pered by the high reactivity of the NꢀR bond that often
leads to the formation of N-bridged imido complexes,
and by the inability of amidoethylpyridine ligands to
offer steric protection to the metal centres. The lack of
rigidity conferred by the C2 chain does not impose a
constrained co-ordination mode of the ligand, a feature
that may be crucial in the stabilisation of the amido
complexes [5,26]. The formation of N-bridged imido
compounds dominated the reactivity pattern observed.
The reactivity of amido and/or imido compounds
with alkylating reagents and Cp− proved to be rather
disappointing. The high insolubility of these complexes
prevented the stereochemical control of subsequent re-
actions, making them poor starting materials and lead-
ing to surprising results, as the formation of
{Ti2[m-N(CH2CH2)py][m-N(CH2CH2)py]%Cl4} with two
different imido-pyridyl ligands disposed in a rarely
observed arrangement.
The results described above are very surprising in
view of the stability of several titanium cyclopentadi-
enylamido complexes [39,40] that have been prepared
by one of the two synthetic approaches tried in this
work. However, the cleavage of an a-carbon nitrogen
bond of the amido ligands has previously been reported
1 Crystal data obtained at room temperature: 8 crystallised in the
orthorhombic system, space group Pbca, with cell parameters a=
,
8.697(2), b=14.593(2), c=17.158(2) A, final R1=0.0454 and wR2=
0.1115.

22
J.R. Ascenso et al. / Journal of Organometallic Chemistry 632 (2001) 17–26
1
4. Experimental
0.20 (s, 18H, Si(CH3)3). H-NMR (CD2Cl2, 300 MHz):
3
l=8.52 (m, 1H, Py H6), 7.57 (td, 1H, JHH=7.8 Hz,
All manipulations, except stated otherwise, were car-
ried out under N2, using either standard Schlenk-line or
4JHH=2.1 Hz, Py H4), 7.10 (m, 2H, Py H3+Py H5),
3.17 (m, 2H, CH2N), 2.84 (m, 2H, CH2py), 0.22 (s,
18H, Si(CH3)3). 13C-NMR (C6D6): l=160.5 (Py C2),
149.9 (Py C6), 135.7 (Py C4), 122.7 (Py C5), 121.0 (Py
C3), 46.5 (CH2N), 44.7 (CH2py), 2.2 (Si(CH3)3). 13C-
NMR (CD2Cl2): l=160.8 (Py C2), 149.9 (Py C6), 136.4
(Py C4), 123.3 (Py C3 or Py C5), 121.5 (Py C3 or Py C5),
46.5 (CH2N), 44.8 (CH2py), 2.4 (Si(CH3)3). Anal.
Found: C, 58.53; H, 9.94; N, 10.53. Calc. for
C13H26N2Si2: C, 58.58; H, 9.83; N, 10.51%. MS: 266
(80) [M+]; 251 (20) [M+−CH3]; 193 (10) [M+−
SiMe3].
,
dry-box techniques. Solvents were pre-dried using 4 A
molecular sieves and refluxed over sodium-benzophe-
none (Et2O, THF and C6H5CH3) or CaH2 (CH2Cl2,
1,2-dichloroethane and n-hexane) under an atmosphere
of N2, and collected by distillation. Deuterated solvents
were dried with molecular sieves and freeze–pump–
1
thaw–degassed prior to use. H- and 13C-NMR spectra
were recorded in a Varian Unity 300, at 298 K unless
otherwise stated, referenced internally to residual pro-
tio-solvent (1H) or solvent (13C) resonances and re-
ported relative to TMS (l 0). Assignments were
supported by NOE spectra (1- and 2D) experiments
and by one bond 13C{1H} hetero-correlations, as ap-
propriate. Mass spectra were performed at IST, Lisbon,
Portugal and Universite´ de Rouen, Rouen, France.
Elemental analyses were obtained from the Laborato´rio
de Ana´lises do IST (Fisons Instrument 1108).
4.2. Synthesis of N(H)(SitBuMe2)CH2CH2py (1b)
Triethylamine (90 ml, 645.7 mmol) was added to a
solution of 2%-aminoethyl-2-pyridine (15.66 g, 128.2
mmol) in 150 ml of CH2Cl2. The mixture was heated to
35°C and a solution of SitBuMe2Cl (21.27 g, 141.0
mmol) in CH2Cl2 was added dropwise. The mixture was
refluxed for 2 h. The volatiles were removed under
vacuum and the residue extracted with n-hexane. The
solvent was removed under reduced pressure leaving
27.88 g of a pale-yellow oil (92% yield). 1H-NMR
(C6D6, 300 MHz): l=8.46 (m, 1H, Py H6), 7.07 (td,
CF3SO3SiMe3, PMe3 (1.0 mol dm−3 in C6H5CH3),
LiNMe2,
aminoethylpyridine,
Et3N,
SiMe3Cl,
SitBuMe2Cl, n-LiBu (1.6 mol dm−3 in hexanes), TiCl4
and NaH (60% dispersion in mineral oil) were pur-
chased from Aldrich. CF3SO3SiMe3, PMe3 and LiNMe2
were used as received. 2%-Aminoethyl-2-pyridine was
purified by distillation over potassium hydroxide. Tri-
ethylamine was pre-dried with molecular sieves,
refluxed over CaH2 and collected by distillation.
SiMe3Cl was purified by removal of residual HCl (by
bubbling nitrogen through for ca. 15 min.) and then
distilled trap-to-trap. SitBuMe2Cl was freeze–pump–
thaw–degassed prior to use. The n-LiBu solution was
titrated by usual methods before use. TiCl4 was freeze–
pump–thaw–degassed and then distilled trap-to-trap.
NaH was washed with THF prior to use. The com-
pounds NaC5H5 [44], CpTiCl3 [45] and 2%-(N-phenyl-
amino)ethyl-2-pyridine [46] were prepared according to
literature methods.
3
4
1H, JHH=7.8 Hz, JHH=1.8 Hz, Py H4), 6.76 (d, 1H,
3JHH=7.8 Hz, Py H3), 6.64 (m, 1H, Py H5), 3.17 (m,
2H, CH2N), 2.77 (m, 2H, CH2py), 0.50 (s, 1H, N(H)),
0.88 (s, 9H, SiC(CH3)3), −0.048 (s, 6H, Si(CH3)2).
13C-NMR (C6D6): l=161.0 (Py C2), 149.7 (Py C6),
135.5 (Py C4), 123.3 (Py C5), 120.9 (Py C3), 43.7
(CH2N), 42.9 (CH2py), 26.6 (SiC(CH3)3), 18.56
(SiC(CH3)3), −4.9 (Si(CH3)2). Anal. Found: C, 63.40;
H, 10.59; N, 11.83. Calc. for C13H24N2Si: C, 66.04; H,
10.23; N, 11.85%. MS: 237 (95) [M+]; 221 (20) [M+−
Me]; 179 (100) [M+−tBu]; 123 (12) [M+−SitBuMe2].
4.3. Synthesis of N(SiMe3)(SitBuMe2)CH2CH2py (1c)
4.1. Synthesis of N(SiMe3)2CH2CH2py (1a)
A solution of 1b (27.89 g, 118.0 mmol) in 200 ml of
Et2O was cooled to 0°C and Et3N (50 ml, 358.7 mmol)
was added. CF3SO3SiMe3 (23.5 ml, 129.8 mmol) was
added dropwise and the mixture was stirred for 4 days
at r.t. A mixture of two phases was formed: a pink
heavy phase, containing the triflate salts, and a yellow
phase, containing 1b. The lighter phase was decanted
and the volatiles were removed under vacuum. The
resulting residue was extracted with n-hexane and the
solvent evaporated under reduced pressure, leaving a
To a solution of 2%-aminoethyl-2-pyridine (12.35 g,
101.1 mmol) in CH2Cl2 (200 ml), Et3N (50 ml, 358.7
mmol) was added. The mixture was cooled to 0°C and
SiMe3Cl (40.0 ml, 315.2 mmol) was added dropwise. A
white precipitate appeared immediately. The mixture
was stirred for 15 h at room temperature (r.t.). The
volatiles were removed under vacuum. The residue was
extracted with n-hexane. The solvent was removed un-
der reduced pressure leaving 25.93 g of a colourless oil
1
pale-yellow oil (36.0 g, 98.9% yield). H-NMR (C6D6,
1
(96% yield). H-NMR (C6D6, 300 MHz): l=8.48 (m,
300 MHz): l=8.45 (m, 1H, Py H6), 7.05 (td, 1H,
3JHH=7.8 Hz, 4JHH=1.8 Hz, Py H4), 6.75 (d, 1H,
3JHH=7.8 Hz, Py H3), 6.61 (m, 1H, Py H5), 3.36 (m,
2H, CH2N), 2.94 (m, 2H, CH2py), 0.92 (s, 9H,
1H, Py H6), 7.04 (td, 1H, 3JHH=7.8 Hz, 4JHH=1.8 Hz,
3
Py H4), 6.75 (d, 1H, JHH=7.8 Hz, Py H3), 6.61 (m,
1H, Py H5), 3.27 (m, 2H, CH2N), 2.89 (m, 2H, CH2py),

J.R. Ascenso et al. / Journal of Organometallic Chemistry 632 (2001) 17–26
23
SiC(CH3)3), 0.25 (s, 9H, Si(CH3)3), 0.22 (s, 6H,
(SiC(CH3)3), −1.94 (Si(CH3)2). Anal. Found: C, 39.84;
H, 6.01; N, 7.18. Calc. for TiC13H23N2SiCl3: C, 40.07;
H, 5.95; N, 7.19%.
1
Si(CH3)2). H-NMR (CD2Cl2, 300 MHz): l=8.52 (m,
3
4
1H, Py H6), 7.58 (td, 1H, JHH=7.80 Hz, JHH=1.80
Hz, Py H4), 7.10 (m, 2H, Py H3+Py H5), 3.22 (m, 2H,
CH2N), 2.89 (m, 2H, CH2py), 0.93 (s, 9H, SiC(CH3)3),
0.25 (s, 9H, Si(CH3)3), 0.23 (s, 6H, Si(CH3)2). 13C-NMR
(C6D6): l=160.5 (Py C2), 149.9 (Py C6), 135.8 (Py C4),
122.6 (Py C3 or Py C5), 121.1 (Py C3 or Py C5), 47.6
(CH2N), 44.4 (CH2py), 27.8 (SiC(CH3)3), 20.2
(SiC(CH3)3), 3.1 (Si(CH3)3), −2.2 (Si(CH3)2). 13C-
NMR (CD2Cl2): l=160.7 (Py C2), 149.9 (Py C6), 136.5
(Py C4), 123.1 (Py C3), 121.5 (Py C5), 47.6 (CH2N), 44.4
(CH2py), 28.0 (SiC(CH3)3), 20.4 (SiC(CH3)3), 3.2
(Si(CH3)3), −2.2 (Si (CH3)2). Anal. Found: C, 61.91;
H, 10.59; N, 9.32. Calc. for C16H32N2Si2: C, 62.27; H,
10.45; N, 9.07%. MS: 309 (100) [M+]; 293 (30) [M+−
CH3]; 235 (30) [M+−SiMe3]; 251 (100) [M+−tBu].
4.6. Reaction of {Ti[N(SiMe3)CH2CH2py]Cl3} (2a)
with NaCp
To a solution of 2a (0.511 g, 1.47 mmol) in 40 ml of
THF, cooled to −95°C, a solution of NaCp (0.138 g,
1.57 mmol) in ca. 15 ml of THF was added dropwise.
The mixture was stirred for 5.5 h as it slowly warmed to
r.t. A white solid precipitated out of a deep-red solu-
tion, and was filtered off. Volatiles were removed and
the residue was washed with n-hexane and then ex-
tracted with Et2O. Upon solvent removal, a brownish
1
solid was obtained in 65% yield. H-NMR (C6D6, 300
MHz): l=8.44 (m, 1H, Py H6), 7.07 (m, 1H, Py H),
6.58 (m, 2H, Py H), 6.19 (s, 5H, h5-C5H5), 5.91 (s,
(h5-C5H5)2TiCl2), 4.58 (m, 2H, CH2N), 3.14 (m, 2H,
CH2py), 0.24 (s, 9H, Si(CH3)3).
4.4. Synthesis of {Ti[N(SiMe3)CH2CH2py]Cl3} (2a)
TiCl4 (2.1 ml, 19.26 mmol) in 100 ml of C6H5CH3
was cooled to −80°C. A solution of 1a (5.132 g, 19.26
mmol) in C6H5CH3 was added dropwise. The mixture
was allowed to warm slowly to r.t. while stirring for 19
h. A dark-orange microcrystalline precipitate formed
and was filtered off. The solid was washed with n-hex-
ane and dried under dynamic vacuum (4.161 g, 62%
yield). A second crop of dark-orange crystals (1.795 g)
was obtained by keeping the mother liquor at −20°C
4.7. Synthesis of {Ti[NCH2CH2py]Cl2}n (3b)
A solution of TiCl4 (0.50 ml, 4.53 mmol) in 1,2-
dichloroethane at 0°C, was added dropwise to a solu-
tion of 1a (1.206 g, 4.53 mmol) in 1,2-dichloroethane.
The mixture was stirred for 48 h at 80°C. A bright-red
solid was filtrated and washed with n-hexane and Et2O.
The solid was dried under dynamic vacuum (0.968 g,
89% yield). Anal. Found: C, 34.85; H, 3.42; N, 11.85.
Calc. for TiC7H8N2Cl2: C, 35.18; H, 3.37; N, 11.72%.
1
for 2 days (global yield: 89%). H-NMR (CD2Cl2, 300
3
4
MHz): l=8.75 (m, 1H, JHH=6.0 Hz, JHH=0.8 Hz,
3
4
Py H6), 7.90 (td, 1H, JHH=7.7 Hz, JHH=1.5 Hz, Py
H4), 7.43 (m, 2H, Py H3+Py H5), 4.63 (m, 2H, CH2N),
3.41 (m, 2H, CH2py), 0.47 (s, 9H, Si(CH3)3). 13C-NMR
(CD2Cl2): l=157.1 (Py C2), 149.2 (Py C6), 140.2 (Py
C4), 125.8 (Py C3), 122.7 (Py C5), 48.8 (CH2N), 39.0
(CH2py), 0.19 (Si(CH3)3). Anal. Found: C, 34.45; H,
4.95; N, 8.14. Calc. for TiC10H17N2SiCl3: C, 34.56; H,
4.93; N, 8.06%.
4.8. Synthesis of {Ti2[v-NCH2CH2py]2Cl4(THF)2} (3c)
The dissolution of 2a or 2b in THF at r.t. affords
overnight a bright-red crystalline insoluble solid in al-
most quantitative yield. Crystals suitable for X-ray
diffraction were obtained. Anal. Found: C, 41.63; H,
5.41; N, 8.81. Calc. for Ti2C22H32N4O2Cl4: C, 42.47; H,
5.18; N, 9.01%.
4.5. Synthesis of {Ti[N(SitBuMe2)CH2CH2py]Cl3} (2b)
TiCl4 (0.275 ml, 2.50 mmol) in 40 ml of C6H5CH3
was cooled to −80°C and solution of 1c (0.773 g, 2.50
mmol) in C6H5CH3 was added dropwise. The mixture
was allowed to warm slowly to r.t. as it stirred
overnight. A bright-red precipitate formed quantita-
tively and was filtered off. The solid was washed with
4.9. Synthesis of {Ti2[v-NCH2CH2py]2Cl4(PMe3)2}
(3d)
1
n-hexane and dried under dynamic vacuum. H-NMR
To a solution of 2b, prepared in situ as described in
Section 4.6 and left stirring for 12 h, one equivalent of
PMe3 was added dropwise. The mixture was stirred for
5 h at r.t. and a yellow solid precipitated in almost
quantitative yield. Anal. Found: C, 37.72; H, 5.58; N,
8.63. Calc. for Ti2C20H34N4P2Cl4: C, 37.75; H, 5.44; N,
8.89%.
(CD2Cl2, 300 MHz): l=8.71 (m, 1H, Py H6), 7.91 (td,
3
4
1H, JHH=7.8 Hz, JHH=1.8 Hz, Py H4), 7.43 (m, 2H,
Py H3+Py H5), 4.74 (m, 2H, CH2N), 3.45 (m, 2H,
CH2py), 1.02 (s, 9H, SiC(CH3)3), 0.55 (s, 6H, Si(CH3)2).
13C-NMR (CD2Cl2): l=156.9 (Py C2), 149.2 (Py C6),
140.6 (Py C4), 126.0 (Py C3), 123.1 (Py C5), 49.5
(CH2N), 40.0 (CH2py), 28.2 (SiC(CH3)3), 25.8

24
J.R. Ascenso et al. / Journal of Organometallic Chemistry 632 (2001) 17–26
56.46 mmol) in 200 ml of n-hexane at −60°C. The
mixture was allowed to warm slowly to r.t. After 40
min at r.t. a yellow solution was formed. SiMe3Cl (14
ml, 110 mmol) was added dropwise at r.t. The reaction
vessel was closed and the mixture was heated at 30°C
overnight. The volatiles were removed under vacuum
and the residue extracted with n-hexane. The solvent
was evaporated under reduced pressure leaving 14.69 g
4.10. Reaction of {Ti[NCH2CH2py]Cl2}n (3b) with
LiNMe2
A solution of LiNMe2 (0.231g, 4.60 mmol) in ca. 30
ml of THF was added dropwise to a suspension of 3b in
100 ml of THF (1.08g, 4.52 mmol), previously cooled to
−60°C. The mixture was allowed to warm slowly to
r.t. After 15 h, there is a white solid suspended in a
dark-red solution. The solvent was evaporated and the
residue extracted with C6H5CH3. The solvent was re-
moved and the resulting red solid dried under dynamic
vacuum (0.302g, 27.9% yield). 1H-NMR (C6D6, 300
1
of an orange oil (94.4% yield). H-NMR (C6D6, 300
MHz): l=8.49 (m, 1H, Py H6), 7.19 (m, 2H, Hm), 7.01
(m, 3H, Py H4+Ho), 6.86 (m, 1H, Hp), 6.61 (m, 2H, Py
3
H3+Py H5), 3.81 (t, 2H, JHH=7.2 Hz, CH2N), 2.90
3
(t, 2H, JHH=7.2 Hz, CH2py), 0.07 (s, 9H, Si(CH3)3).
MHz): l=9.45 (m, 1H, Py H6), 8.27 (m, 1H, Py H%),
6
1H-NMR (CD2Cl2, 300 MHz): l=8.59 (m, 1H, Py H6),
7.58 (td, 1H, 3JHH=7.8 Hz, 4JHH=1.8 Hz, Py H4),
7.31 (m, 2H, Hm), 7.10 (m, 4H, Py H3+Py H5+Ho),
6.77 (td, 1H, 3JHH=7.8 Hz, 4JHH=1.8 Hz, Py H4),
6.68 (td, 1H, 3JHH=7.7 Hz, 4JHH=1.8 Hz, Py H%),
4
6.41 (m, 2H, Py H3+Py H5), 6.34 (m, 2H, Py H% +Py
3
3
6.94 (m, 1H, Hp), 3.81 (t, 2H, JHH=7.2 Hz, CH2N),
H%), 5.80 (m, 1H, CH2N%), 5.41 (m, 1H, CH2N), 4.99
2.96 (t, 2H, 3JHH=7.2 Hz, CH2py), 0.20 (s, 9H,
Si(CH3)3). 13C-NMR (C6D6): l=160.8 (Py C2), 149.8
(Py C6), 149.1 (Cipso), 135.6 (Py C4), 129.1 (Cm), 123.7
(Py C5), 122.0 (Co), 121.0 (Py C3), 120.5 (Cp), 47.8
(CH2N), 38.3 (CH2py), 0.8 (Si(CH3)3). 13C-NMR
(CD2Cl2): l=160.8 (Py C2), 149.8 (Py C6), 149.1
(Cipso), 136.3 (Py C4), 129.2 (Cm), 124.0 (Py C5), 121.6
(Py C3 or Co), 121.5 (Py C3 or Co), 120.2 (Cp), 48.0
(CH2N), 38.6 (CH2py), 1.0 (Si(CH3)3). Anal. Found: C,
70.78; H, 8.22; N, 10.20. Calc. for C16H22N2Si: C,
71.06; H, 8.20; N, 10.36%. MS: 271 (15) [M+]; 255 (10)
[M+−CH3]; 199 (25) [M+−SiMe3]; 194 (10) [M+−
Ph]; 178 (80) [M+−Me−Ph].
5
(m, 1H, CH2N%), 4.72 (m, 1H, CH2N), 3.48 (m, 1H,
CH2py), 2.93 (m, 1H, CH2py%), 2.77 (m, 1H, CH2py),
2.33 (m, 1H, CH2py%). 13C-NMR (C6D6): l=160.5 (Py
C2 or Py C%), 160.1 (Py C2 or Py C%), 152.4 (Py C%),
2
2
6
150.9 (Py C6), 138.3 (Py C%), 137.8 (Py C4), 124.8 (Py
4
C%), 124.0 (Py C3), 121.8 (Py C5+Py C%), 69.2 (CH2N
3
5
or CH2N%), 59.5 (CH2N or CH2N%), 42.6 (CH2py or
CH2py%), 40.5 (CH2py or CH2py%). Anal. Found: C,
39.52; H, 4.65; N, 12.05; Ti, 17.3. Calc. for
TiC7H8N2Cl2: C, 35.19; H, 3.37; N, 11.72; Ti, 20.0%.
4.11. Synthesis of {CpTi[NCH2CH2py]Cl}n (4b)
4.13. Synthesis of {Ti[N(Ph)CH2CH2py]Cl3} (6)
A solution of NaCp (0.265 g, 3.01 mmol) in THF
was added dropwise to a suspension of 3b (0.693 g, 2.90
mmol) in THF at −30°C. After stirring for 5 h as it
warmed slowly to r.t., a dark-red solution formed. The
solvent was evaporated and the residue washed with
n-hexane and Et2O. The residue was then extracted
with C6H5CH3, giving a dark-red solution. After sol-
vent removal a dark-red solid was obtained. Redissolu-
tion in C6H5CH3 yield, at r.t., a dark microcrystalline
solid that did not redissolve (yield B5%). Anal. Found:
C, 53.73; H, 4.87; N, 10.32. Calc. for TiC12H13N2Cl: C,
53.66; H, 4.88; N, 10.43%. MS:2 1177 (0.5) [5M+−
2Cp−Cl]; 1074 (1) [4M+]; 973 (0.5) [4M+−Cp−Cl];
939 (0.75) [M+−Cp−2Cl]; 895 (0.75) [4M+−Cp−
2Cl−py]; 828 (0.75) [4M+−2Cp−2Cl−py]; 700 (1.5)
A solution of 5 (1.239 g, 4.58 mmol) in C6H5CH3 was
added dropwise to a solution of TiCl4 (0.5 ml, 4.58
mmol) in C6H5CH3 (100 ml) previously cooled to −
60°C. The mixture was allowed to warm slowly to r.t.
while stirring for 15 h. A brown precipitate formed and
was filtered off. The solid was washed with Et2O and
C6H5CH3 and dried under dynamic vacuum (1.446 g,
1
90% yield). H-NMR (CD2Cl2, 300 MHz): l=8.90 (m,
1H, Py H6), 7.93 (m, 1H, Py H4), 7.33 (m, 7H, Harom
+
Py H3+Py H5), 4.80 (m, 2H, CH2N), 3.62 (m, 2H,
CH2py). 13C-NMR (CD2Cl2): l=157.4 (Py C2), 153.7
(Cipso), 149.7 (Py C6), 140.4 (Py C4), 129.6 (Carom), 127.7
(Carom), 125.8 (Py C3), 123.0 (Py C5), 119.9 (Carom), 47.4
(CH2N), 35.9 (CH2py). Anal. Found: C, 44.73; H, 4.02;
N, 7.49. Calc. for TiC13H13N2Cl3: C, 44.42; H, 3.73; N,
7.97%.
[3M+−pyCH2CH2];
599
(10)
[3M+−Cp−
pyCH2CH2]; 403 (20) [2M+−L−N]; 195 (10) [M+−
py].
4.14. Synthesis of {Ti[N(Ph)CH2CH2py]Cl3(THF)} (7)
4.12. Synthesis of N(SiMe3)(C6H5)CH2CH2py (5)
The dissolution of 6 in THF at r.t. affords a dark-
Fourty-four millilitres of n-LiBu in hexanes (1.6
mol dm−3, 70.4 mmol) was added dropwise to a sus-
pension of N-phenyl-2%-aminoethyl-2-pyridine (11.42 g,
brown solution. After removal of the solvent, a yellow-
1
ish solid was obtained in quantitative yield. H-NMR
(CD2Cl2, 300 MHz): l=8.86 (m, 1H, Py H6), 7.92 (td,
3
4
1H, JHH=7.5 Hz, JHH=1.5 Hz, Py H4), 7.43 (m, 6H,
H
arom+Py H3+Py H5), 7.22 (t, 1H, 3JHH=7.2 Hz,
2 M=TiC12H13N2Cl; py=C5H4N; Cp=C5H5; L=NCH2CH2py.

J.R. Ascenso et al. / Journal of Organometallic Chemistry 632 (2001) 17–26
25
4.16. Synthesis of {Cp2Ti2[v-NPh]Cl2} (8)
Hp), 4.75 (m, 2H, CH2N), 3.80 (m, 4H, THF
OCH2CH2), 3.66 (m, 2H, CH2py), 1.85 (m, 4H, THF
OCH2CH2). 13C-NMR (CD2Cl2): l=157.7 (Py C2),
152.1 (Cipso), 149.6 (Py C6), 140.4 (Py C4), 129.5 (Carom),
127.6 (Carom), 125.9 (Py C3), 123.0 (Py C5), 120.2 (Carom),
69.3 (OCH2-THF), 49.8 (CH2N), 36.2 (CH2py), 25.9
(CH2-THF). Anal. Found: C, 47.56; H, 5.04; N, 6.73.
Calc. for TiC17H21N2OCl3: C, 48.20; H, 5.00; N, 6.61%.
N-Phenylaminoethyl-2-piridine (0.449 g, 2.27 mmol)
was dissolved in 20 ml of THF and added dropwise to
a suspension of NaH in 50 ml of THF. After 15 h at
50°C, a red solution was obtained. After being cooled to
−50°C, the solution was filtered to a schlenk containing
CpTiCl3 (0.504 g, 2.30 mmol). After the addition, the
solution becomes darker and a white solid precipitates as
the temperature rises gently over 7 h. The volatiles were
evaporated and the residue, a dark-red solid, was washed
with n-hexane. This solid was extracted with Et2O and
the solution placed at −20°C, from which orange
crystals grew overnight. (YieldB10%). 1H-NMR (C6D6,
4.15. Reaction of {Ti[N(Ph)CH2CH2py]Cl3(THF)} (7)
with NaCp
Compound 6 (0.405 g, 1.15 mmol) was dissolved in ca.
40 ml of THF and the deep-red solution obtained was
cooled to −50°C. NaCp (0.166 g, 1.89 mmol) in ca. 20
ml of THF was added dropwise. The mixture was
allowed to warm to r.t. as it stirred for 5 h. The volatiles
were then removed and the residue was extracted with
C6H5CH3. The solution obtained was concentrated and
placed at −20°C. Bright-red crystals of Cp2Cl2 formed
3
300 MHz): l=7.00 (td, 2H, JHH=7.8 Hz, Hm), 6.78
(m, 2H, Ho), 6.75 (m, 1H, Hp), 6.08 (s, 5H, h5-C5H5).
13C-NMR (C6D6): l=129.3 (Cm), 125.4 (Cp), 121.2
(Co), 118.5 (h5-C5H5). Anal. Found: C, 54.03; H, 4.12;
N, 5.18. Calc. for Ti2C22H20N2Cl2: C, 55.16; H, 4.21; N,
5.85%.
1
overnight (yield B10%). H-NMR (C6D6, 300 MHz):
4.17. X-ray crystallographic study
l=5.91 (s, h5-C5H5). Anal. Found: C, 48.43; H, 3.89.
Calc. for TiC10H10Cl2: C, 48.24; H, 4.05%.
Crystal data for compound 3c was collected in a
MACH 3 (Enraf–Nonius) diffractometer using graphite
,
Table 2
monochromated Mo–Ka radiation (u=0.71069 A) by
Crystal data and structure refinement for 3c
the ꢀ–2q scan-mode. Unit cell dimensions were ob-
tained by least-squares refinement of the setting angles
of 25 reflections (18BqB20°). Data was corrected for
Lorentz polarisation and linear decay (no linear decay
was detected) as well as empirically for absorption using
MOLEN software [47].
Empirical formula
Formula weight
Temperature (K)
Wavelength (A)
Crystal system
Space group
C11H16Cl2N2OTi
311.06
293(2)
0.71069
Monoclinic
P21/c
,
The molecular and crystal structure was solved by a
combination of direct methods and Fourier difference
synthesis and the refinement was based on F2. Non-hy-
drogen atoms were refined with anisotropic thermal
parameter, atom C12 showing a high thermal vibration.
All hydrogens were inserted in idealised positions and
allowed to refine riding in the parent C atom, with
thermal parameter 1.2 times those to which they are
bonded. All remaining crystal data and refinement
parameters are presented in Table 2.
Unit cell dimensions
,
A (A)
8.735(3)
13.975(3)
11.888(3)
90
111.67(2)
90
1348.6(6)
4
1.532
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
3
,
V (A )
Z
−3
,
Dcalc (Mg A
)
Absorption coefficient (mm−1
F(000)
)
1.016
640
0.50×0.40×0.20
Calculations were done using SHELXS-97 [48] and
SHELXL-97 [49]. Graphic presentations were prepared
with ORTEP-III [50]. All of these programs are included
in OSCAIL, version 8 [51].
Crystal size (mm)
Theta range for data collection (°) 2.35–25.97
Index ranges
−105h510, 05k517,
−145l514
5280
Reflections collected
Independent reflections
Reflections observed (\2|)
Refinement method
2644 [Rint=0.0823]
1543
5. Supplementary material
Full-matrix least-squares on
F2
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(I)]
R indices (all data)
2644/6/154
1.048
R1=0.0579, wR2=0.1107
R1=0.1176, wR2=0.1401
0.544 and −0.413
Experimental details, atomic coordinates, bond
lengths and angles for the structural analysis have been
deposited with the Cambridge Crystallographic Data
Centre, CCDC no. 157363 for compound 3c. Copies of
data may be obtained free of charge from The Director,
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK
Largest difference peak and hole
−3
,
(e A
)

26
J.R. Ascenso et al. / Journal of Organometallic Chemistry 632 (2001) 17–26
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