Monocyclopentadienyl titanium complexes supported by functionalized carboxylate ligands

Article abstract of DOI:10.1016/j.ica.2010.10.019

The reaction of [TiCp*Cl₃] with [Fe(η⁵- C₅H₅)(η⁵-C₅H₄COOH)] in the presence of NEt₃ yields [TiCp*{(OOC-C₅H ₄)FeCp}₃] (1), (Cp = η

Full text of DOI:10.1016/j.ica.2010.10.019

Inorganica Chimica Acta 366 (2011) 122–127
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Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Monocyclopentadienyl titanium complexes supported by functionalized
carboxylate ligands
c
a
a
Rosa Fandos a, Carolina Hernández a, Antonio Otero b, , Ana Rodríguez , María José Ruiz , Sara Suizo ,
⇑
Cesar Pastor d, Pilar Terreros e
a Departamento de Química Inorgánica, Orgánica y Bioquímica, Universidad de Castilla-La Mancha, Instituto de Nanociencia, Nanotecnología y Materiales Moleculares (INAMOL),
Facultad de Ciencias del Medio Ambiente. Avda. Carlos III, s/n, 45071 Toledo, Spain
b Departamento de Química Inorgánica, Orgánica y Bioquímica, Universidad de Castilla-La Mancha, Facultad de Químicas, Avda. Camilo José Cela, 10, 13071 Ciudad Real, Spain
c Departamento de Química Inorgánica, Orgánica y Bioquímica, Universidad de Castilla-La Mancha ETS Ingenieros Industriales. Avda. Camilo José Cela, 3, 13071 Ciudad Real, Spain
d Servicio Interdepartamental de Apoyo a la Investigación, Facultad de Ciencias, Universidad Autónoma de Madrid, Spain
e Instituto de Catálisis y Petroleoquímica, CSIC, Cantoblanco, 28049 Madrid, Spain
a r t i c l e i n f o
a b s t r a c t
The reaction of [TiCp*Cl3] with [Fe(g g
5-C5H5)(
5-C5H4COOH)] in the presence of NEt3 yields [TiCp*{(OOC–
Article history:
Received 10 May 2010
Received in revised form 8 October 2010
Accepted 16 October 2010
Available online 15 December 2010
C5H4)FeCp}3] (1), (Cp =
g g
5-C5H5). The alkyl complex [TiCp*Me3] reacts with [FeCp( 5-C5H4–CH2COOH)]
or anthranilic acid rendering the tris-carboxylate titanium complexes [TiCp*{(OOCCH2–C5H4)FeCp}3]
(2) and [TiCp*{(OOCC6H4NH2)3] (3), respectively. Complex 3 can be protonated with triflic acid to render
[TiCp*{(OOCC6H4NH2)3].HOTf (4). The reaction of [TiCp*Me3] with anthranilic acid in a 1:2 M ratio yields
t
the alkyl carboxylate derivative [TiCp*Me{(OOCC6H4NH2)2] (5). Complex 5 reacts with BuNC to render
Keywords:
Titanium
Carboxylate
Ferrocenyl ligands
the iminoacyl complex [TiCp*(
roceneacetic acid, gives [TiCp*Cl2{(OOCCH2–C5H4)FeCp}] (7). The [TiCp*Cl]2(
be obtained by reaction of [TiCp*Cl3] with [Fe(
5-C5H4–COOH)2] in the presence of a base. The molecular
structures of 1 and 8 have been established by X-ray diffraction methods.
Ó 2010 Elsevier B.V. All rights reserved.
g
2-MeCNtBu){(OOCC6H4NH2)2] (6). The reaction of [TiCp*Cl3] with the fer-
l
–O)[(JJC–C5H4)2Fe] (8) can
g
1. Introduction
The ferrocene backbone provides for a relatively rigid coordina-
tion environment and it is known that the incorporation of an elec-
tron rich transition metal in the complex can stabilize electron
deficient and cationic early transition metal complexes [6].
We report here our results on the preparation and structural
characterization of a series of monocyclopentadienyl titanium
complexes containing functionalized carboxylate ligands.
Titanium is a metal used on a wide range of materials support-
ing medical applications. It is therefore of great interest to investi-
gate simple complexes that could act as structural models of the
intricate interaction between titanium biological molecules with
which it comes in contact. In this sense, carboxylate and amine
functions are ubiquitous in biological molecules and therefore it
is important to study their titanium coordination chemistry [1].
Moreover, carboxylates [2] are versatile ligands because appro-
priate substitution patterns allow substantial changes on the steric
and electronic properties of the metal center and on account of that
are common groups in systems of catalytic utility. In addition, they
offer a great variety of coordination modes and this makes them
interesting in the construction of molecular architectures [3,4].
We have focused our work on the synthesis and study of tita-
nium carboxylates with amino or ferrocene functions. In spite of
the extensive work on the symmetrical and unsymmetrical ferr-
ocenyl ligands [5] the chemistry of monocyclopentadienyl deriva-
tives of titanium with this type of ligand remains practically
unexplored.
2. Results and discussion
The titanium derivative [TiCp*Cl3] reacts with ferrocenecarbox-
ylic acid [Fe(g g
5-C5H5)( 5-C5H4COOH)] in the presence of NEt3 in
toluene at room temperature rendering the tris-carboxylate tita-
nium complex [TiCp*{(OOC–C5H4)FeCp}3] (1) (Scheme 1). In this
complex three carboxylate chelate moieties from three ferrocenyl
ligands are coordinated to a titanium center.
Complex 1 has been characterized by the usual spectroscopic
techniques. The 1H NMR spectrum shows a singlet signal at
2.06 ppm corresponding to the Cp* group, two multiplet signals
at 4.00 and 4.90 ppm corresponding to the carboxylic cyclopenta-
dienyl moiety and a singlet at 4.38 ppm assigned to the Cp group
bonded to the iron atom. The 13C NMR data are also in agreement
with the coordination of the carboxylate groups as depicted in
Scheme 1.
⇑
Corresponding author. Fax: +34 926 295318.
E-mail address: antonio.otero@uclm.es (A. Otero).
0020-1693/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2010.10.019

R. Fandos et al. / Inorganica Chimica Acta 366 (2011) 122–127
123
Ti
O
O
O
O
O
O
C
O
+3 NEt3
Fe
OH
Ti
Cl
+
Fe
- 3 NEt3HCl
Cl
Cl
Fe
Fe
1
Scheme 1.
Table 1
Selected bond lengths [Å] and angles [°] for 1 and 8.
1
8
Bond distances
Ti(1)–O(4)
Ti(1)–O(6)
Ti(1)–O(1)
Ti(1)–O(3)
Ti(1)–O(2)
Ti(1)–O(5)
2.071(3)
2.121(3)
2.123(3)
2.189(3)
2.195(3)
2.203(3)
Ti(1)–O(3)
Ti(1)–O(1)
Ti(1)–O(2)
Ti(1)–Cl(1)
Ti(1)–C(9)
C(1)–O(2)
C(1)–O(1)
C(1)–C(2)
1.819(1)
2.107(1)
2.143(1)
2.3193(7)
2.355(2)
1.271(3)
1.277(3)
1.462(3)
Bond angles
C(2)–O(4)–Ti(1)
C(2)–O(3)–Ti(1)
C(1)–O(2)–Ti(1)
C(1)–O(1)–Ti(1)
O(6)–Ti(1)–O(1)
O(4)–Ti(1)–O(3)
O(4)–Ti(1)–O(6)
O(4)–Ti(1)–O(1)
93.1(3)
87.9(2)
89.4(3)
92.9(3)
74.3(1)
61.4(1)
132.3(1)
130.4(1)
O(2)–C(1)–O(1)
O(2)–C(1)–C(2)
O(1)–C(1)–C(2)
Ti(1)–O(3)–Ti(1)a
O(1)–Ti(1)–O(2)
O(3)–Ti(1)–Cl(1)
O(1)–Ti(1)–Cl(1)
117.3(2)
123.6(2)
119.2(2)
132.1(1)
61.59(6)
97.04(3)
134.41(5)
a
Symmetry operation used to generated the atom: ꢀx + 2, y, ꢀz + 1/2.
Fig. 1. Perspective ORTEP (30%) of the molecular structure of complex 1.
In order to accurately establish the structure of complex 1 we
have carried out its characterization by X-ray diffraction methods.
An ORTEP of 1 is shown in Fig. 1, and some selected bond distances
and angles are summarized in Table 1. The structure consists of
discrete molecules separated by van der Waals distances. The tita-
In this way, compound 3 reacts with triflic acid to yield a new
complex, 4, that has been characterized by the usual analytical
and spectroscopic techniques (Scheme 3).
The 1H NMR spectrum of compound 4 shows a broad signal at
5.95 ppm that is assigned to the seven protons of the amine and
ammonium groups. The 13C NMR spectrum indicates that all the
three aromatic rings are in the same chemical environment. The
spectrum shows only one signal, at 187.4 ppm, corresponding to
the carboxylate moieties. All this data could indicate that there is
a rapid proton transfer between all the three anthranilate groups
in the NMR time scale. A VTNMR experiment shows that even at
223 K the proton transfer process is rapid in the NMR time scale.
As we have seen, the reaction of [TiCp*Me3] with the corre-
sponding carboxylic acid is a good synthetic procedure for the
preparation of tricarboxylate derivatives. However, because of
the high polarity of the Ti–C bonds and the acidity of carboxylic
acids normally it is not possible to carry out the protonolysis reac-
tion of the Ti–Me bonds in a stepwise manner in order to isolate
the carboxylate alkyl complex. Probably the lack of an appropriate
synthetic procedure of such derivatives has prevented a systematic
study of the reactivity of the Ti–C bond in complexes with carbox-
ylate groups as ancillary ligands.
nium atom is bonded to the cyclopentadienyl ring in a
and to three carboxylate groups in a bidentate fashion.
g
5-mode
The geometry around the metal center can be described as a
distorted pentagonal pyramid. The Ti–O bond distances range from
2.071(3) to 2.203(3) Å and compare well with that found in the
tris-carboxylate titanium derivative [TiCp*(O2CPh)3] [7].
The synthesis of carboxylate derivatives can also be achieved by
reaction of metal-alkyl complexes with the corresponding carbox-
ylic acid [8]. In this way, the titanium alkyl derivatives [TiCp*Me3]
reacts with ferroceneacetic or anthranilic acid, at room tempera-
ture, to yield the tri carboxylate compounds 2 or 3, respectively
(Scheme 2).
This procedure can also be used to prepare complex 1, by reac-
tion of [TiCp*Me3] with [Fe(g g
5-C5H5)( 5-C5H4COOH)].
Complexes 2 and 3 are air stable and have also three chelate
carboxylate moieties. They have been characterized by the usual
spectroscopic techniques. As an example the 1H NMR of 2 shows
singlet signals at 1.89 ppm and 3.32 ppm assigned to the Cp*
ligand and to the methylene moieties, respectively. The aromatic
protons of the ferrocenyl ligands appear at 3.93, 4.00 and
4.19 ppm.
Compound 3 is interesting in several ways, both because the
anthranilate group can behave as a N and O donor ligand and
can therefore can be a good model of the interaction between tita-
nium with biological molecules, and also because it has NH2R moi-
eties that can be easily protonated to yield cationic derivatives.
The reaction of [TiCp*Me3] with anthranilic acid in a 1:2 M ratio,
in pentane at low temperature, yields the corresponding dicarbox-
ylate compound 5 (Scheme 4) along with small amounts of 3 (ca.
5%). In contrast, complexes 1 or 2 were the only isolated products
when different molar ratios of [TiCp*Me3] and ferrocenecarboxylic
or ferroceneacetic acid, respectively, were employed.
Complex 5 has been isolated as an air sensitive orange solid, sol-
uble in CH2Cl2 and THF and less soluble in pentane. It has been
spectroscopically characterized.

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R. Fandos et al. / Inorganica Chimica Acta 366 (2011) 122–127
2
5
4
6
4
2
Scheme 2.
Scheme 3.
Scheme 4.
O
C
OH
+ NEt 3
- NEt 3HCl
Ti
+
Fe
Ti
Cl
O
Cl
Cl
Cl
C
Cl
O
Fe
7
Scheme 5.
Firstly, we have carried out the reaction of 5 with tert-butyliso-
cyanide in a 1:1 M ratio to yield an air sensitive orange solid which
was identified as complex 6 (See Scheme 4).
The 1H NMR spectrum of complex 7 shows two singlet signals at
2.01 and 3.07 ppm assigned to the Cp* group and to the methylene
protons of the ferrocenyl ligand. The resonances of the cyclopenta-
dienyl protons appear as multiplet absorptions at 3.85, 3.90, and
4.00 ppm.
The 1H NMR spectrum shows singlet signals at 1.53, 1.93 and
2.49 ppm which are assigned to the tert-butyl group, the Cp* ligand
and the inserted methyl moiety, respectively. In addition, the spec-
trum shows a broad signal at 5.68 ppm corresponding to the amine
protons and three multiplet signals due to the aromatic protons.
Furthermore, 13C NMR shows, among others, two singlet signals at
227.3 and 179.4 ppm which we assign to the iminoacyl carbon atom
and to the carboxylic groups of the anthranilate ligands. All those
data suggest that complex 6 has reacted with tert-Butylisocyanide
to yield a rather symmetric compound. In order to know the orien-
tation of the imine fragment a NOESY experiment was carried out.
The response in the 1H NOESY-1D experiment from the Cp* ligand
upon irradiating the methyl groups of iminoacyl fragment indicate
that in solution the orientation depicted in Scheme 4 is preferred.
Finally, in order to prepare chloro-carboxylate derivatives we
have studied the reaction of the starting compound [TiCp*Cl3] with
ferroceneacetic acid in the presence of NEt3 at room temperature in
1:1 M ratio, we have found the mono-carboxylate titanium com-
plex [TiCp*Cl2{(OOCCH2–C5H4)FeCp}] (7) is produced (Scheme 5).
Complex 7 has been characterized by 1H and 13C NMR as well as
by elemental analysis and IR spectroscopy.
The reaction of the starting compound [TiCp*Cl3] with [Fe(g5
-
C5H4–COOH)2] in a 2:1 M ratio in the presence of NEt3, proceeds
in toluene, at room temperature, to yield the heterometallic com-
plex [TiCp*Cl]2(l-O)[(JJC–C5H4)2Fe] (8) (Scheme 6), in which
two titanium centers are connected throughout an oxo bridging li-
gand. Compound 8 is also obtained if the reaction of [TiCp*Cl3]
with [Fe(g
5-C5H4–COOH)2] is carried out in a 1:1 M ratio.
Probably, the presence of the oxo group is the result of a hydro-
lysis process due to some residual moisture in the solvent. The for-
mation of oxo-containing derivatives by reaction of early transition
metal complexes with carboxylic acids is not unusual. In this way,
the use of organic carboxylic acids to modify the reactivity of tita-
nium alkoxides has led to the isolation of a variety of complex mol-
ecules containing titanium oxo-alkoxide cores coordinated by
carboxylate ligands [9].
Complex 8 has been characterized by NMR and IR spectroscopy
as well as by elemental analysis and X-ray diffraction. The 1H NMR
spectrum shows the resonance corresponding to the Cp* ligand at
2.12 ppm while those assigned to the carboxylate cyclopentadienyl

R. Fandos et al. / Inorganica Chimica Acta 366 (2011) 122–127
125
O
+ 4 NEt3
+ H2O
O
Ti
OH
Ti
Cl
Fe
+
2
Ti
Cl
Cl
Cl
- 4 NEt3HCl
O
Cl
O
O
O
OH
Fe
O
8
Scheme 6.
The Ti(1)–Ti(1)a distance (3.3258(1) Å) is short and it falls into
the range observed for dinuclear oxo bridged titanium systems
[8,11,12]. Besides, the X-ray data indicate that the crystals are a
racemic mixture of both RR and SS isomers.
All complexes reported in this paper show IR bands for which
D
m
as(COO)– s(COO) values are in agreement with a bidentate coordi-
m
nation of the carboxylate group to the titanium center [13].
3. Conclusion
In conclusion, we report in this paper the synthesis of a series of
complexes containing monocyclopentadienyl titanium units with
different functionalized carboxylate moieties. We have seen that
although the NH2 moiety of the anthranilate group does interact
with the titanium center it can play a role on the reactivity of
the complex because it acts as basic center that can be protonated
to yield cationic derivatives. We have also been able to synthesize a
methyl carboxylate complex and we have studied the reactivity of
t
the Ti–Me bond with BuNC. Studies in order to know how the re-
dox state of the iron affects the electron density at the titanium
atom are underway.
Fig. 2. Perspective ORTEP (30%) of the molecular structure of complex 8.
4. Experimental section
group appear at 3.67, 3.82, 4.77 and 4.82 ppm. The ratio of the inte-
grals is consistent with the proposed stoichiometry while the num-
ber of signals indicates that the four protons in each carboxylate
cyclopentadienyl ligand are unequivalent. The 13C NMR spectrum
is in agreement with the proposed disposition. Both titanium
atoms in complex 8 are chiral centers and the 1H NMR spectrum
shows that only the SS and/or the RR isomers are isolated. Forma-
tion of the SR isomer is, probably prevented by the rigid nature of
the bridging carboxylate ligand.
The coordination mode of the ferrocenyl ligand has been con-
firmed by an X-ray diffraction study. An ORTEP of 8 is shown in
Fig. 2, and some selected bond distances and angles are summa-
rized in Table 1.
The structure consists of discrete trimetallic molecules sepa-
rated by van der Waals distances. The structure around the two
titanium atoms in the molecule is that of a pseudo-square pyrami-
dal geometry. The ferrocene dicarboxylate moiety is bridging the
two titanium centers. Furthermore, each of the two titanum atoms
is bonded to a Cp* group, to a chlorine atom and to an oxo bridging
ligand.
4.1. General procedures
The preparation and handling of described compounds was per-
formed with rigorous exclusion of air and moisture under nitrogen
atmosphere using standard vacuum line and Schlenk techniques.
All solvents were dried and distilled under a nitrogen atmosphere.
The following reagents were prepared by literature procedures:
[TiCp*Me3] [14] and [TiCp*Cl3] [15]. The commercially available
compounds were used as received from Aldrich.
1H and 13C NMR spectra were recorded on a 200 Mercury Varian
or on a 400 Avance Bruker Fourier Transform Spectrometers. Trace
amounts of protonated solvents were used as references, and
chemical shifts are reported in units of parts per million relative
to SiMe4.
IR spectra were recorded in the region 4000–400 cmꢀ1 with a
Nicolet Magna-IR 550 spectrophotometer.
4.2. Synthesis
It is noteworthy that the rigid nature of the bridging ferrocene
carboxylate ligand imposes some specific structural parameters.
The Ti–O bond distance (Ti(1)–O(3), 1.8195(11) is within the range
4.2.1. Synthesis of [TiCp*{(OOC–C5H4)FeCp}3] (1)
To a solution of [TiCp*Cl3] (0.235 g, 0.81 mmol) in 10 mL of tol-
uene were added ferrocenecarboxylic acid (0.560 g, 2.43 mmol)
and 0.339 mL (2.43 mmol) of NEt3 at room temperature, and the
mixture was stirred for 18 h. After that, the solvent was evaporated
and the residue washed with pentane (8 mL), yielding complex 1 as
expected for
Ti–O–Ti bond angle (132.11(14)°) is wider than that found in
di- -oxo–dititanium complexes but it is in the range expected
l-oxo–dititanium bridging systems [10] and the
l
for dinuclear derivatives bridged only through an oxo ligand
[8,11]. The Ti(1)–O(1) and Ti(1)–O(2) bond distances (2.107(2)
and 2.143(2) Å, respectively) are somewhat longer than those in
1 but are within the range expected for bidentate carboxylate tita-
nium derivatives [7].
an orange solid (0.364 g, 52%). IR (KBr, cmꢀ1): 1540 (vs
m
as(COO)),
1465 (vs s(COO)),
m
D
= 75 cmꢀ1
.
1H NMR (C6D6, rt): d 2.06 (s, 15 H,
Cp*), 4.00 (s, 6 H, CH), 4.38 (s, 15 H, CH), 4.9 (s, 6 H, CH).
13C{1H}NMR (C6D6, rt): 11.6 (Cp*), 70.2 (CH), 70.5 (CH), 71.3

126
R. Fandos et al. / Inorganica Chimica Acta 366 (2011) 122–127
(CH), 77.0 (Cipso), 134.9 (Cp*), 187.9 (COO). Anal. Calc. for
43H42Fe3O6Ti: C, 59.34; H, 4.86. Found: C, 59.47; H, 4.95%.
H, Ar), 7.97 (m, 2 H, Ar). 13C{1H} NMR (CD2Cl2, rt): 12.1 (Cp*),
116.7 (Cipso), 117.3 (Ar), 131.1 (Cp*), 131.4 (Ar), 136.9 (Ar), 152.3
(Cipso), 187.4 (COO). Anal. Calc. for C32H34F3N3O9STi: C, 51.82; H,
4.62, N, 5.66. Found: C, 51.29; H, 4.83, N, 5.48%.
C
4.2.2. Synthesis of [TiCp*{(OOCCH2–C5H4)FeCp}3] (2)
To a mixture of [TiCp*Me3] (0.205 g, 0.89 mmol) and ferrocene-
acetic acid (0.657 g, 2.67 mmol) was added toluene (7 mL) at room
temperature and the mixture was stirred for 3 h. After that, the sol-
vent was evaporated and the residue washed with pentane to yield
a yellow solid, which was characterized as 2 (0.589 g, 72 %). IR
4.2.5. Synthesis of [TiCp*Me{(OOCC6H4NH2)2] (5)
To a solution of [TiCp*Me3] (0.310 g, 1.37 mmol) in 10 mL of
pentane at ꢀ40 °C was added anthranilic acid (0.375 g, 2.74 mmol).
The mixture was allowed to reach the room temperature and then
was added toluene (2 mL) at room temperature. The mixture was
stirred for 3 h. After that, the solvents were filtered and the residue
washed with pentane to yield an orange solid, which was charac-
(KBr, cmꢀ1): 1545 (vs = 76 cmꢀ1 1H
mas(COO)), 1469 (vs ms(COO)), D .
NMR (C6D6, rt): d 1.89 (s, 15 H, Cp*), 3.32 (s, 6 H, CH2), 3.93 (m,
6 H, CH), 4.00 (m, 15 H, CH), 4.19 (m, 6 H, CH). 13C{1H}NMR
(C6D6, rt): 11.5 (Cp*), 38.0 (CH2), 67.9 (CH), 69.2 (CH), 80.6 (Cipso),
131.0 (Cp*), 187.3 (COO). Anal. Calc. for C46H48Fe3O6Ti: C, 60.56;
H, 5.30. Found: C, 60.66; H, 5.43%.
terized as 5 (0.450 g, 70 %). IR (KBr, cmꢀ1): 1528 (m,
mas(COO)),
1441 (s, s(COO)),
m
D
= 87 cmꢀ1 1H NMR (CDCl3, rt): d 0.91 (s, 3 H,
.
Me), 2.03 (s, 15 H, Cp*), 5.67 (br, 4 H, NH2), 6.66 (m, 4 H, Ar),
7.26 (m, 2 H, Ar), 7.88 (m, 2 H, Ar). 13C{1H} NMR (CDCl3, rt): 11.6
(Cp*), 68.9 (Me), 111.4 (Cipso), 116.1 (Ar), 116.4 (Ar), 128.0 (Cp*),
131.6 (Ar), 134.4 (Ar), 150.6 (Cipso), 182.3 (COO).
4.2.3. Synthesis of [TiCp*{(OOCC6H4NH2)3] (3)
To a mixture of [TiCp*Me3] (0.230 g, 1.01 mmol) and anthranilic
acid (0.414 g, 3.02 mmol) was added dichloromethane (5 mL) at
room temperature, and the mixture was stirred for 3 h. After that,
the solvent was evaporated and the residue washed with pentane
to yield a yellow crystalline solid, which was characterized as 3
4.2.6. Synthesis of [TiCp*(2-MeCNtBu){(OOCC6H4NH2)2] (6)
To a solution of compound 5 (0.321 g, 0.67 mmol) in 8 mL of
CH2Cl2 at room temperature was added tBuNC (0.057 g,
0.67 mmol). The mixture was stirred for 1 h. After that, the solvent
was evaporated under vacuum and the residue washed with pen-
tane to yield an orange solid, which was characterized as 5
(0.560 g, 94 %). IR (KBr, cmꢀ1): 1568 (m,
D
m
as(COO)), 1469 (s,
ms(COO)),
= 99 cmꢀ1. 1H NMR (CDCl3, rt): d 2.12 (s, 15 H, Cp*), 5.61 (br, 6 H,
NH2), 6.57 (m, 3 H, Ar), 6.62 (m, 3 H, Ar), 7.21 (m, 3 H, Ar), 7.88 (m,
3 H, Ar). 13C{1H} NMR (CDCl3, rt): 11.6 (Cp*), 112.6 (Cipso), 116.1
(Ar), 116.3 (Ar), 129.0 (Cp*), 131.5 (Ar), 133.8 (Ar), 149.9 (Cipso),
182.5 (COO). Anal. Calc. for C31H33O6N3Ti: C, 62.94; H, 5.62, N,
7.10. Found: C, 62.58; H, 5.70, N, 7.01%.
(0.181 g, 48 %). IR (KBr, cmꢀ1): 1512 (s,
m
as(COO)), 1445 (s,
ms(COO)),
t
D
= 67 cmꢀ1
.
1H NMR (CDCl3, rt): d 1.53 (s, 9 H, Bu), 1.93 (s, 15
H, Cp*), 2.49 (s, 3 H, Me), 5.68 (br, 4 H, NH2), 6.62 (m, 4 H, Ar),
7.21 (m, 2 H, Ar), 7.86 (m, 2 H, Ar). 13C{1H} NMR (CDCl3, rt): 11.4
(Cp*), 17.5 (Me), 29.7 (tBu), 62.2 (tBu), 114.2 (Cipso), 115.8 (Ar),
116.0 (Ar), 121.7 (Cp*), 131.2 (Ar), 132.8 (Ar), 149.7 (Cipso), 179.4
(COO), 227.3 (CN). Anal. Calc. for C30H39O4N3Ti: C, 65.10; H, 7.09;
N, 7.59. Found: C, 65.08; H, 6.98, N, 7.26%.
4.2.4. Synthesis of [TiCp*{(OOCC6H4NH2)3]ꢁHOTf (4)
To a solution of compound 3 (0.235 g, 0.39 mmol) in CH2Cl2, at
room temperature, was added HOTf (35 lL, 0.39 mmol) and the
mixture was stirred for 3 h. After that, the solvent was evaporated
and the residue washed with Et2O to yield a red crystalline solid,
which was characterized as 4 (0.155 g, 53 %). IR (KBr, cmꢀ1):
4.2.7. Synthesis of [TiCp*Cl2{(OOCCH2–C5H4)FeCp}] (7)
To a solution of [TiCp*Cl3] (0.246 g, 0.85 mmol) in 10 mL of tol-
uene were added ferroceneacetic acid (0.211 g, 0.85 mmol) and
0.118 mL (0.85 mmol) of NEt3 at room temperature, and the mix-
ture was stirred for 16 h. After filtration, the solvent was evaporated
1567 (vs mas(COO)), 1485 (vs ms(COO)), D .
= 82 cmꢀ1 1H NMR (CD2Cl2,
rt): d 2.06 (s, 15 H, Cp*), 5.95 (br, 7 H, NH2), 6.74 (m, 4 H, Ar),
6.84 (m, 2 H, Ar), 7.29 (m, 1 H, Ar), 7.44 (m, 2 H, Ar), 7.85 (m, 1
Table 2
Crystal data and structure refinement for 1 and 8ꢁC7H8.
1
8ꢁC7H8
Molecular formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
C43H42Fe3O6Ti
870.22
200(2)
0.71073
monoclinic
P21/n
10.8864(8)
10.4805(7)
33.068(2)
98.765(3)
3728.8(4)
4
1.550
1.399
1792
0.42 ꢂ 0.14 ꢂ 0.11
1.25–26.39
ꢀ13 6 h 6 13
–12 6 k 6 13
–41 6 l 6 41
32461
C39H45Cl2FeO5Ti2
816.30
100(2)
1.54178
monoclinic
C2/c
11.0151(2)
30.7297(7)
11.3000(2)
101.852(1)
3743.4(1)
4
1.448
8.264
1692
0.25 ꢂ 0.22 ꢂ 0.12
2.88–70.38
ꢀ13 6 h 6 13
–37 6 k 6 34
–12 6 l 6 13
9139
b (Å)
c (Å)
b (°)
Volume (Å3)
Z
Density (calculated) (g/cm3)
Absorption coefficient (mmꢀ1
F(0 0 0)
)
Crystal size (mm3)
Theta range for data collection (°)
Index ranges
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness-of-fit on F2
7626 [R(int) = 0.0949] 3521 [R(int) = 0.0395]
7626/0/483
0.990
3521/0/312
0.993
Final R indices [I > 2
r
(I)]
R1 = 0.0563
wR2 = 0.1226
R1 = 0.0383
wR2 = 0.0995
0.524 and ꢀ0.566
Largest difference in peak and hole 0.629 and ꢀ0.591

R. Fandos et al. / Inorganica Chimica Acta 366 (2011) 122–127
127
and the residue washed with pentane (7 mL) to yield complex 7 as
an orange solid (0.200 g, 47%). IR (KBr, cmꢀ1): 1542 (m,
as(COO)),
1469 (vs s(COO)),
= 73 cmꢀ1 1H NMR (C6D6, rt): d 2.01 (s, 15 H,
Consolider-Ingenio 2010 ORFEO CSD2007-00006) and the Junta
de Comunidades de Castilla-La Mancha, Spain (Grant No. PCI08-
0010).
m
m
D
.
Cp*), 3.07 (s, 2 H, CH2), 3.85 (m, 2 H, CH), 3.90 (s, 5 H, CH), 4.00
(m, 2 H, CH). 13C{1H} NMR (C6D6, rt): 12.4 (Cp*), 35.0 (CH2), 68.1
(CH), 69.0 (CH), 69.1 (CH), 79.9 (Cipso), 176.1 (COO). Anal. Calc. for
References
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C22H26Cl2FeO2Ti: C, 53.15; H, 5.27. Found: C, 53.13; H, 5.27%.
4.2.8. Synthesis of [TiCp*Cl]2( -O)[(JJC–C5H4)2Fe (8)
l
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0.55 mmol) and 0.306 mL (2.20 mmol) of NEt3, and the mixture
was stirred at room temperature for 4 h. After filtration, the solvent
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55%). IR (KBr, cmꢀ1): 1531 (vs
mas(COO)), 1455 (vs ms(COO)),
D
= 76 cmꢀ1 1H NMR (C6D6, rt): d 2.12 (s, 30 H, Cp*), 3.67 (m, 2
.
H, CH), 3.82 (m, 2 H, CH), 4.77 (m, 2 H, CH), 4.82 (m, 2 H, CH).
13C{1H}NMR (CD2Cl2): 11.2 (Cp*), 69.7 (CH), 70.1 (CH), 71.1 (CH),
72.5 (CH), 130.9 (Cp*), 185.7 (COO). Anal. Calc. for C39H46Cl2O5Fe-
Ti2: C, 57.31; H, 5.67. Found: C, 57.63; H, 5.87%.
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Mo K
a
radiation (k = 0.71073 Å). X-ray data were collected at
and scans.
200 K, with a combination of three runs at different
u
x
A red single crystal of 8ꢁC7H8 with prismatic shape was mounted on
a glass fibber and transferred to a Bruker SMART 6K CCD area-
detector three-circle diffractometer with a Rotating Anode (Cu
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Ka
radiation, k = 1.54178 Å) generator equipped with Goebel mir-
rors at settings of 50 kV and 110 mA. X-ray data were collected
at 100 K, with a combination of five runs at different and
u
x
scans. For both compounds the substantial redundancy in data al-
lows semi-empirical absorption corrections (SADABS) [16] to be ap-
plied using multiple measurements of symmetry-equivalent
reflections. The raw intensity data frames were integrated with
the SAINT [17] program, which also applied corrections for Lorentz
and polarization effects.
The software package SHELXTL [18] was used for space group
determination, structure solution and refinement. The space group
determination was based on a check of the Laue symmetry and sys-
tematic absences and was confirmed using the structure solution.
The structure was solved by direct method (SHELXS-97) [19], com-
pleted with difference Fourier syntheses, and refined with full-ma-
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[16] G.M. Sheldrick, SADABS Version 2004/1, A Program for Empirical Absorption
Correction, University of Göttingen, Göttingen, Germany, 2004.
trix least-squares using SHELXL-97 [20] minimizing
x
(F20 ꢀ F2c )2.
Weighted R factors (Rw) and all goodness of fit S are based on F2;
conventional R factors (R) are based on F. All non-hydrogen atoms
were refined with anisotropic displacement parameters.
[17] SAINT
Madison, Wisconsin, USA, 2004.
[18] SHELXTL NT Version 6.12, Structure Determination Package, Bruker-Nonius AXS,
+ v7.12a, Area-Detector Integration Program, Bruker-Nonius AXS,
-
Madison, Wisconsin, USA, 2001.
[19] G.M. Sheldrick, SHELXS-97, Program for structure solution, Acta Crystallogr.,
Sect. A 46 (1990) 467.
Acknowledgements
[20] G.M. Sheldrick, SHELXL-97, Program for Crystal Structure Refinement,
Universität Göttingen, 1997.
This work was supported by the Ministerio de Ciencia e
Innovación, Spain
(Grant. Nos. CTQ2008-00318/BQU and