Synthesis of new organotitanium (IV) complexes Cp2Ti(SeR) 2 and Cp2TiCl(SeR) via tandem reactions involving 'Cp 2Ti' intermediate. Crystal structures of Cp2TiCl(SeR) (R=p-ClC6H4, p-BrC6H4)

Article abstract of DOI:10.1016/j.ica.2003.06.011

A simple and convenient route for synthesizing organotitanium (IV) complexes with a general formula Cp₂Ti(SeR)₂ or Cp ₂TiCl(SeR) has been developed. This synthetic route includes reduction of Cp₂TiCl₂ with Mg and an in situ treatment of the intermediate 'Cp₂Ti' with diselenides RSeSeR. Interestingly, while the route involving reaction of Cp₂TiCl₂, Mg and RSeSeR in a molar ratio of 1:1:1 produced Cp₂Ti(SeR)₂, (1-5, R=α-C₁₀H₇, o-MeC₆H₄, m-MeC₆H₄, p-ClC₆H₄, p-BrC ₆H₄) in 91-97% yields, the route involving reaction of Cp₂TiCl₂, Mg and RSeSeR in a molar ratio of 1: 0.5: 0.5 afforded Cp₂TiCl(SeR) (6-7, R=p-ClC₆H₄, p-BrC₆H₄) in 70% and 92% yields, respectively. 1-7 are new and have been characterized by elemental analysis and spectroscopy, as well as by X-ray diffraction analysis for 6 and 7. A possible pathway for production of these two types of organotitanium (IV) complexes, mainly depending upon the molar ratio of the starting materials, are briefly discussed.

Full text of DOI:10.1016/j.ica.2003.06.011

Inorganica Chimica Acta 357 (2004) 2199–2204
www.elsevier.com/locate/ica
Synthesis of new organotitanium (IV) complexes Cp2Ti(SeR)2 and
Cp2TiCl(SeR) via tandem reactions involving ÔCp2TiÕ
intermediate. Crystal structures of Cp2TiCl(SeR)
(R ¼ p-ClC6H4, p-BrC6H4)
a,
a
a
Li-Cheng Song *, Cong Han , Qing-Mei Hu a,b, Zhi-Pan Zhang
a
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
b
State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
Received 2 April 2003; accepted 18 June 2003
Available online 25 September 2003
Abstract
A simple and convenient route for synthesizing organotitanium (IV) complexes with a general formula Cp2Ti(SeR)2 or
Cp2TiCl(SeR) has been developed. This synthetic route includes reduction of Cp2TiCl2 with Mg and an in situ treatment of
the intermediate ÔCp2TiÕ with diselenides RSeSeR. Interestingly, while the route involving reaction of Cp2TiCl2, Mg and
RSeSeR in a molar ratio of 1:1:1 produced Cp2Ti(SeR)2, (1–5, R ¼ a-C10H7, o-MeC6H4, m-MeC6H4, p-ClC6H4, p-BrC6H4) in
91–97% yields, the route involving reaction of Cp2TiCl2, Mg and RSeSeR in a molar ratio of 1: 0.5: 0.5 afforded
Cp2TiCl(SeR) (6–7, R ¼ p-ClC6H4, p-BrC6H4) in 70% and 92% yields, respectively. 1–7 are new and have been characterized
by elemental analysis and spectroscopy, as well as by X-ray diffraction analysis for 6 and 7. A possible pathway for pro-
duction of these two types of organotitanium (IV) complexes, mainly depending upon the molar ratio of the starting materials,
are briefly discussed.
Ó 2003 Elsevier B.V. All rights reserved.
Keywords: Cp2Ti-containing complexes; Selenolate ligand; Chloride ligand; Synthesis; Crystal structures
1. Introduction
initiated a study on this route utilizing Cp2TiCl2 as a
ÔCp2TiÕ source to see if the reaction of Cp2TiCl2 with Mg
followed by treatment of the intermediate ÔCp2TiÕ with
RSeSeR could give the expected Cp2Ti/selenolate-con-
taining complexes. Interestingly, the study has shown
that such tandem reactions can produce not only the
expected symmetrical Cp2Ti(SeR)2, but also the un-
symmetrical Cp2TiCl(SeR), mainly depending upon the
molar ratio of the starting materials Cp2TiCl2, Mg and
RSeSeR. Herein we report the synthesis and spectro-
scopic characterization of Cp2Ti(SeR)2 (R ¼ a-C10H7,
o-MeC6H4, m-MeC6H4, p-ClC6H4, p-BrC6H4) and
Cp2TiCl(SeR) (R ¼ p-ClC6H4, p-BrC6H4), as well as the
crystal structures of Cp2TiCl(SeC6H4Cl-p) Cp2TiCl
(SeC6H4Br-p). A possible mechanism accounting for the
formation course of these two types of organotitanium
(IV) complexes is preliminarily suggested.
Organotitanium compounds Cp2TiCl2 [1–3] and
Cp2Ti(CO)2 [4–6] are known to be important ÔCp2TiÕ
sources for preparation of a wide variety of Cp2Ti-
containing complexes. Recently, we prepared a series of
Cp2Ti-containing
complexes
Cp2Ti(SR)2
using
Cp2TiCl2 as a ÔCp2TiÕ source and indicated that it is a
more convenient and environmently benign reagent
(without involving toxic CO) than Cp2Ti(CO)2 in the
preparation of such organotitanium complexes [7].
Considering that this route might be applied to
synthesize their selenium analogues Cp2Ti(SeR)2, we
* Corresponding author. Fax : +86-22-2350-4853.
E-mail address: lcsong@public.tpt.tj.cn (L.-C. Song).
0020-1693/$ - see front matter Ó 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2003.06.011

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L.-C. Song et al. / Inorganica Chimica Acta 357 (2004) 2199–2204
2. Results and discussion
2.1. Preparation and characterization of Cp2Ti(SeR)2
(1–5) and Cp2TiCl(SeR) (6–7)
It was shown that 2 mmol of magnesium turnings
reacted in THF with 1 mmol of 1,2-dibromoethane
followed by treatment of the activated Mg (ca. 1 mmol)
with 1 mmol of Cp2TiCl2 to give a brown-green solution
containing ca. 1 mmol of ÔCp2TiÕ intermediate [7]. Fur-
ther treatment of the intermediate ÔCp2TiÕ with 1 mmol
of diselenides RSeSeR resulted in an immediate color
change from brown-green to purple and finally to
greenish purple, from which a series of new organoti-
tanium (IV) complexes 1–5 were obtained in 91–97%
yields, as shown in Scheme 1.
1–5 are purple solids, which dissolve in polar organic
solvents such as CH2Cl2, CHCl3, acetone and THF.
Although 1–5 are air-stable in solids, they are quite air-
and light-sensitive in solution. 1–5 were characterized by
elemental analysis and spectroscopic data, which coin-
cide very well with their structures shown in Scheme 1.
The 77Se NMR spectra of 1–5 each showed one singlet
in the range 915.16–1025.01 ppm for their two identical
Se atoms, whereas the 1H NMR spectra of 1–5 each
displayed one singlet at ca. 6 ppm for the 10 Cp protons.
The IR spectra of 1–5 exhibited the absorption bands
similar to those of other Cp2Ti-containing compounds,
especially the strong band characteristic of the C–H out-
of-plane deformations of the Cp rings in the range
808–828 cmꢀ1 [8].
Fig. 1. The partial 1H NMR spectrum of the mixture of Cp2TiBr
(SeC6H4Cl-p) and Cp2TiCl(SeC6H4Cl-p).
As mentioned above in the preparation of 1–5, the
color change from brown-green to purple and then to
greenish purple took place when RSeSeR was added to
ÔCp2TiÕ intermediate. This might imply that another type
of intermediate was produced from ÔCp2TiÕ. In order to
prove this, we separated the purple intermediate ap-
peared in the preparation of complex 4. The partial mass
Fig. 2. The partial mass spectrum of the mixture of Cp2TiBr
(SeC6H4Cl-p) and Cp2TiCl(SeC6H4Cl-p).
1
spectrum and H NMR spectrum of this intermediate
are shown in Figs. 1 and 2, which indicate that the
corresponding fragment ion peaks and the 1H NMR
spectrum exhibits two singlets, one at 6.25 ppm assigned
to the two identical Cp rings of Cp2TiBr(SeC6H4Cl-p)
and another at 6. 29 ppm attributed to Cp rings of
Cp2TiCl(SeC6H4Cl-p).
In order to eliminate Cp2TiBr(SeC6H4Cl-p), which
apparently is derived from MgBr2 (produced in the ac-
tivation procedure of magnesium turnings with 1,2-
dibromoethane), the reactions were attempted using
freshly crushed magnesium powders instead of the ac-
tivated magnesium turnings. Fortunately, it was found
that when 1 mmol of Cp2TiCl2 reacted with 0.5 mmol of
freshly crushed Mg powders in THF at room tempera-
ture followed by treatment of ca. 0.5 mmol of the in-
termediate ÔCp2TiÕ with 0.5 mmol of diselenides RSeSeR
(R ¼ p-ClC6H4, p-BrC6H4), the corresponding unsym-
metrical organotitanium (IV) complexes 6 and 7 were
supposed intermediate is actually
a mixture of
Cp2TiCl(SeC6H4Cl-p) and Cp2TiBr(SeC6H4Cl-p). This
is because that the mass spectrum displays the molecular
ion peaks at m=z ¼ 447.8 for Cp2TiBr(SeC6H4Cl-p) and
m=z ¼ 404.0 for Cp2TiCl(SeC6H4Cl-p) as well as the
Scheme 1.

L.-C. Song et al. / Inorganica Chimica Acta 357 (2004) 2199–2204
2201
obtained in 70% and 92% yields, respectively, as shown
in Scheme 2.
6 and 7 are air-stable, purple solids, which are easily
soluble in polar organic solvents such as CH2Cl2, CHCl3
and THF to give light-stable, but air-sensitive solutions.
These products were characterized by elemental analy-
sis, IR and 1H NMR spectroscopy. For example, the 1H
NMR spectra of 6 and 7 each showed one singlet at 6.26
ppm for their Cp rings, whereas the IR spectra displayed
the absorption bands characteristic of 1–5 and those of
other compounds containing Cp2Ti moieties [8]. In fact,
the structures of 6 and 7 have been confirmed by crystal
X-ray diffraction studies (vide infra).
Fig. 3. Molecular structure of 7 showing the atom labeling scheme.
entially react via step (v) with the excess Cp2TiCl2 to
give Cp2TiCl(SeR), which along with Cp2TiCl(SeR)
produced in step (iii) cannot be able to turn into
Cp2Ti(SeR)2 via step (iv) owing to the absence of
RSeMgCl (consumed in the reaction with excess
Cp2TiCl2). Finally, it is worth pointing out that the
pathway based on the elementary steps described above
is reasonable, since some of the steps, for example, step
(i) [1,7] and step (iv) [9,10] have precedents and the
pathway is completely consistent with the facts observed
in the preparation of 1–7.
2.2. Consideration of the possible pathway for formation
of 1–7
The possible pathway for production of 1–7, shown
in Scheme 3, is suggested.
That is, 1–5 were possibly produced through (i)–(iv)
elementary steps, whereas 6 and 7 were yielded most
likely via (i)–(iii) and (v) steps. These steps include: (i)
reduction of Cp2TiCl2 with Mg to produce ÔCp2TiÕ and
MgCl2; (ii) metathesis between RSeSeR and MgCl2 to
give RSeCl and RSeMgCl; (iii) oxidative addition of
ÔCp2TiÕ with RSeCl to give Cp2TiCl(SeR); (iv) nucleo-
philic substitution of Cp2TiCl(SeR) with RSeMgCl to
yield Cp2Ti(SeR)2; and (v) nucleophilic substitution of
Cp2TiCl2 with RSeMgCl to afford Cp2TiCl(SeR).
Apparently, 6 and 7 can only be obtained as major
products when excess Cp2TiCl2 is used in the reaction
with Mg followed by treatment with RSeSeR (R ¼
p-ClC6H4, p-BrC6H4). This is because that the corre-
sponding RSeMgCl generated in step (ii) would prefer-
2.3. X-ray structural analyses of 6 and 7
To unequivocally confirm the structures of 6 and 7,
the X-ray diffraction analyses of 6 and 7 were under-
taken. Since the perspective views of 6 and 7 are very
similar, only the view of 7 is presented in Fig. 3. The
selected bond lengths and angles of 6 and 7 are given in
Table 1. As can be seen in Fig. 3, complex 7 consists of
Table 1
ꢀ
Selected bond lengths (A) and angles (°) for 6 and 7
SeR
6
Bond lengths
Ti
Cl
C(11)–Se(1)
Se(1)–Ti(1)
Ti(1)–C(1)
Ti(1)–C(9)
1.919(5) Cl(2)–C(14)
2.535(3) C(1)–C(2)
2.384(6) C(11)–C(12)
2.396(5) Ti(1)–Cl(1)
1.747(6)
1.371(8)
1.403(7)
2.399(3)
Product
6
7
R
p-ClC6H4
p-BrC6H4
Yield (%)
70
92
Bond angles
C(11)–Se(1)–Ti(1)
C(4)–Ti(1)–C(5)
C(1)–Ti(1)–C(10)
C(1)–Ti(1)–Se(1)
107.93(17) Cl(1)–Ti(1)–Se(1)
95.78(5)
75.28(18)
94.54(15)
35.0(3)
145.2(2)
77.32(2)
C(2)–Ti(1)–Se(1)
Cl(1)–Ti(1)–C(2)
Scheme 2.
C(13)–C(14)–Cl(2) 120.5(4)
(i) Cp2TiCl2
(ii) RSeSeR
+
Mg
’Cp 2Ti ’ + MgCl2
7
Bond lengths
C(11)–Se(1)
Se(1)–Ti(1)
Ti(1)–C(1)
Ti(1)–C(9)
+
MgCl2
RSeCl
Cp2Ti
+
RSeMgCl
SeR
Cl
1.891(7) Br(1)–C(14)
2.515(5) C(1)–C(2)
1.862(7)
1.41(3)
1.41(2)
2.381(5)
(iii) ’C p 2Ti ’
+
RSeCl
2.363(13) C(8)–C(9)
2.377(14) Ti(1)–Cl(1)
SeR
SeR
SeR
Cl
+
+
MgCl2
MgCl2
(iv)
Cp2Ti
+
RSeMgCl
Cp2Ti
Bond angles
C(11)–Se(1)–Ti(1)
C(4)–Ti(1)–C(5)
C(1)–Ti(1)–C(10)
C(1)–Ti(1)–Se(1)
107.6(3)
Cl(1)–Ti(1)–Se(1)
C(2)–Ti(1)–Se(1)
Cl(1)–Ti(1)–C(2)
95.78(16)
76.3(5)
94.5(4)
SeR
Cl
(v) Cp2TiCl2
+
RSeMgCl
35.3(8)
93.8(5)
77.2(5)
Cp2Ti
C(13)–C(14)–Br(1) 121.4(5)
Scheme 3.

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L.-C. Song et al. / Inorganica Chimica Acta 357 (2004) 2199–2204
Table 2
Comparison of some geometric parameters in 6, 7 and Cp2Ti(SPh)2
6
7
Cp2Ti(SPh)2
Bond angle of Se–Ti–Cl (°) or S–Ti–S (°)
Dihedral angle between two Cp (°)
Distance from Ti to centroids of two Cp (A)
95.78(5)
50.1
95.78(6)
51.7
99.3(3)
47.6
ꢀ
2.065/2.070
2.535(3)
2.042/2.042
2.515(5)
2.067/2.072
2.395(8)/2.042(8)
ꢀ
Bond length of Ti–Se (A) or Ti–S (A)
ꢀ
one Cl and one p-BrC6H4Se ligands coordinated to ti-
tanium atom of its Cp2Ti, respectively. It is noteworthy
that the plane defined by Cl(1)–Ti(1) and Se(1) atoms
divides the bent Cp2Ti structural unit into two equal
parts and the two Cp groups symmetrically occupy the
opposite sides of the plane. In fact, 6 and 7 are iso-
structural, of which the geometry around the Ti center is
similar to the corresponding that of Cp2Ti(SPh)2 [11].
For comparison, some of their parameters are listed in
Table 2.
mg (1.0 mmol) of di-a-naphthyl diselenide to cause an
immediate color change from brown-green to purple.
The mixture continued to be stirred at r.t. for 2 h to give
a greenish purple solution. Solvent was removed at re-
duced pressure to give a residue, which was subjected to
column chromatography. The major band was eluted
using CH2Cl2/petroleum ether (v/v ¼ 1:1) to give 534 mg
(91%) of 1 as a purple solid, which was further purified
by recrystallization from CH2Cl2/hexane. M.p. 150–153
°C. Anal. Found: C, 61.20; H, 4.10. Calc. for
C30H24Se2Ti: C, 61.04%; H, 4.10%. IR (KBr disk,
cmꢀ1): m 3432 (vs), 1556 (m), 1494 (m), 1435 (m), 1373
(m), 1019 (s), 957 (m), 828 (vs), 793 (vs), 766 (vs), 649
3. Experimental
1
(m), 532 (m). H NMR (CDCl3, d, ppm): 5.98 (s, 10H,
2C5H5), 7.46–8.37 (m, 14H, 2C10H7). 77Se NMR
All reactions were carried out under a highly purified
Ar atmosphere using standard Schlenk or vacuum-line
techniques. Tetrahydrofuran (THF) was dried and de-
oxygenated by distillation from sodium/benzophenone
ketyl. Magnesium, CH2Cl2, hexane, petroleum ether
(30–60 °C) and alumina were available commercially.
Cp2TiCl2 [12], and R2Se2 (R ¼ a-C10H7; o-MeC6H4, m-
C6H4, p-ClC6H4, p-BrC6H4) [13] were prepared ac-
cording to literature methods. Products were separated
by a chromatographic column packed with Al2O3 and
recrystallized from CH2Cl2/hexane under anaerobic
conditions. IR spectra were recorded on either a Bio-
Rad FTS 135 or a Nicolet 560 E.S.P. spectrophotome-
(CDCl3, Me2Se, d, ppm): 915.16.
3.2. Preparation of Cp2Ti(SeC6H4Me-o)2 (2)
Similarly, from 342 mg (1.00 mmol) of (o-
MeC6H4)2Se2, 501 mg (97%) of 2 was obtained as a
purple solid. M. p. 235-236 °C. Anal. Found: C, 55.32;
H, 4.73. Calc. for C24H24Se2Ti: C, 55.62; H, 4.67%. IR
(KBr disk, cmꢀ1): m 3437 (m), 1462 (s), 1438 (s), 1375
1
(m), 1034 (s), 1010 (s), 820 (vs), 749 (vs), 654 (m). H
NMR (CDCl3, d, ppm): 2.40 (s, 6H, 2CH3), 5.96 (s,
10H, 2C5H5), 7.10–7.80 (m, 8H, 2C6H4). 77Se NMR
(CDCl3, Me2Se, d, ppm): 1021.68.
1
ter, while H NMR and 77Se NMR (relative to Me2Se)
spectra were recorded on a Bruker AC-P200 and a
Varian UNITY-Plus 400 spectrometers, respectively.
Elemental analyses were performed on an Elementar
Vario EL analyzer. Melting points were determined on a
Yanaco MP-500 micromelting point apparatus.
3.3. Preparation of Cp2Ti(SeC6H4Me-m)2 (3)
Similarly, from 342 mg (1.00 mmol) of (m-
MeC6H4)2Se2, 495 mg (96%) of 3 was obtained as a
purple solid. M. p. 196–197 °C. Anal. Found: C, 55.76;
H, 4.70. Calc. for C24H24Se2Ti: C, 55.62%; H, 4.67%. IR
(KBr disk, cmꢀ1): m 3448 (m), 1586 (m), 1562 (m), 1468
(m), 1436 (m), 1066 (m), 1018 (m), 991 (w), 818 (vs), 782
(s), 762 (s), 688 (s). H NMR (CDCl3, d, ppm): 2.33 (s,
6H, 2CH3), 5.99 (s, 10H, 2C5H5), 7.02–7.45 (m, 8H,
2C6H4). 77Se NMR (CDCl3, Me2Se, d, ppm): 1011.09.
3.1. Preparation of Cp2Ti(SeC10H7-a)2 (1)
A 100 ml three-necked flask equipped with a mag-
netic stir-bar, a serum cap and an Ar inlet tube was
charged with 50 mg (2.0 mmol) of fine magnesium
turnings, 10 ml of THF and 0.085 ml (1.0 mmol) of 1,2-
Br2C2H4. The reaction mixture was heated gently with
stirring until gas evolution ceased after about 5 min and
then 249 mg (1.0 mmol) of bis(g5-cyclopentadienyl)di-
chlorotitanium was added. The mixture was stirred at
r.t. for about 0.5 h, at which time most of the activated
Mg disappeared to give a brown-green THF solution of
the ÔCp2TiÕ intermediate. To this solution was added 412
1
3.4. Preparation of Cp2Ti(SeC6H4Cl-p)2 (4)
Similarly, from 382 mg (1.00 mmol) of (p-ClC6H4)2Se2,
538 mg (96%) of 4 was obtained as a purple solid. M. p.

L.-C. Song et al. / Inorganica Chimica Acta 357 (2004) 2199–2204
2203
Table 3
Crystal data and structural refinements details for 6 and 7
solution containing the intermediate ÔCp2TiÕ. To this so-
lution was added 191 mg (0.50 mmol) of (p-ClC6H4)2Se2.
The mixture continued to be stirred for 4 h to give a purple
solution. Solvent was removed in vacuo and the residue
was subjected to column chromatography. The major
band was eluted with CH2Cl2/petroleum ether/THF (v/v/
v ¼ 1:1:0.1) to afford 141 mg (70%) of 6 as a purple solid.
M. p. 147–150 °C. Anal. Found: C, 47.40; H, 3.49. Calc.
for C16H14Cl2SeTi: C, 47.54; H, 3.49%. IR (KBr disk,
cmꢀ1): m 3112 (vs), 3097 (vs), 1468 (vs), 1441 (vs), 1382 (s),
1366 (m), 1087 (vs), 1067 (m), 1012 (vs), 944 (m), 820 (vs),
728 (m). 1H NMR (CDCl3, d, ppm): 6.26 (s, 10H, 2C5H5),
7.24, 7.29, 7.34, 7.48 (q, AA0BB0, 4H, C6H4).
6
7
Empirical formula
Formula weight
Temperature (K)
Crystal system
Space group
C16H14Cl2SeTi
404.03
293(2)
C16H14BrClSeTi
448.49
293(2)
orthorhombic
P2ð1Þ 2(1) 2(1)
10.728(12)
11.579(13)
12.594(14)
1564(3)
4
orthorhombic
P2ð1Þ 2(1) 2(1)
10.690(18)
11.435(18)
12.57(2)
1537(3)
4
ꢀ
a (A)
ꢀ
b (A)
ꢀ
c (A)
3
ꢀ
V (A )
Z
Dcalc (g cmꢀ3
F ð000Þ
)
1.716
800
32.01
1.938
872
56.84
l(Mo KaÞ (cmꢀ1
)
ꢀ
Wavelength (A)
Scan type
0.71073
x-2h
46.72
0.71073
x-2h
46.72
3.7. Preparation of Cp2TiCl(SeC6H4Br-p) (7)
2hmax (°)
Reflections collected
5304
Independent reflections 2266
4488
2024
Similar to the preparation of 6, when using 234 mg
(0.50 mmol) of (p-BrC6H4)2Se2 205 mg (92%) of 7 was
obtained as a purple solid. M.p. 156–159 °C. Anal. Found:
C, 42.84; H, 3.26. Calc. for C16H14BrClSeTi: C, 42.85; H,
3.15%. IR (KBr disk, cmꢀ1): m 3111 (vs), 3095 (vs), 1477
(s), 1462 (vs), 1438 (vs), 1376 (s), 1069 (vs), 1018 (vs), 1003
(vs), 944 (m), 838 (s), 818 (vs), 705 (m). 1H NMR (CDCl3,
d, ppm): 6.26 (s, 10H, 2C5H5), 7.41, 7.45, 7.50, 7.54 (q,
AA0 BB0, 4H, C6H4).
Rint
0.0454
0.0454
0.0553
R ½I > 2rðIÞꢂ
Rw ½I > 2rðIÞꢂ
Goodness-of-fit on F2
0.0326
0.0670
0.985
0.1292
1.022
Largest differenꢀc3e peak 0.313 and )0.243
0.791 and )0.879
ꢀ
and hole (eA
)
191–192 °C. Anal. Found: C, 47.35; H, 3.28. Calc. for
C22H18Cl2Se2Ti: C, 47.26%; H, 3.25%. IR (KBr disk,
cmꢀ1): m 3454 (m), 1466 (vs), 1434 (m), 1379 (m), 1086 (vs),
1010 (vs), 808 (vs), 721 (m), 483 (s). 1H NMR (CDCl3, d,
ppm): 5.93 (s, 10H, 2C5H5), 7.18, 7.22, 7.46, 7.50 (q, AA0
BB0, 8H, 2C6H4). 77Se NMR (CDCl3, Me2Se, d, ppm):
993.02.
3.8. X-ray structural determinations of 6 and 7
Single crystals of 6 and 7 suitable for X-ray diffraction
analysis were grown from their CH2Cl2/hexane solution
at )20 °C. A crystal (0.35 ꢁ 0.30 ꢁ 0.25 mm3 for 6 and
0.30 ꢁ 0.25 ꢁ 0.20 mm3 for 7) was mounted onto a glass
fiber and placed on a Bruker Smart 1000 CCD diffrac-
tometer with graphite-monochromated Mo Ka radiation
ꢀ
(k ¼ 0:71073 A). With the SHELXS-97 and SHELXS-97
3.5. Preparation of Cp2Ti(SeC6H4Br-p)2 (5)
package the structures were solved by direct method and
the final refinement was performed by full-matrix least-
squares methods on F2 with anisotropic thermal param-
eters for non-hydrogen atoms. The calculations were
performed on a Bruker Smart computer. Details of the
crystal data, data collections and structural refinements
for 6 and 7 are summarized in Table 3.
Similarly, from 469 mg (1.00 mmol) of (p-
BrC6H4)2Se2, 627 mg (97%) of 5 was obtained as a purple
solid. M.p. 180–181 °C. Anal. Found: C, 40.70; H, 2.63.
Calc. for C22H18Br2Se2Ti: C, 40.78%; H, 2.80%. IR (KBr
disk, cmꢀ1): m 3447 (s), 1474 (w), 1455 (s), 1431 (m), 1369
(m), 1073 (s), 1027 (m), 999 (vs), 820 (vs), 797 (s), 700 (m),
478 (s). 1H NMR (CDCl3, d, ppm): 5.99 (s, 10H, 2C5H5),
7.39, 7.43, 7.46, 7.50 (q, AA0BB0, 8H, 2C6H4). 77Se NMR
(CDCl3, Me2Se, d, ppm): 1025.01.
4. Supplementary material
3.6. Preparation of Cp2TiCl(SeC6H4Cl-p) (6)
Crystallographic data for the structures reported in
this paper have been deposited with the Cambridge
Crystallographic Data Center, CCDC nos. 201900 for 6
and 201901 for 7. Copies of this information may be ob-
tained free of charge from The Director, CCDC, 12 Union
Road, Cambridge, CB2 1EZ, UK (fax: +44-1223-336033;
e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
A 100 ml three-necked flask equipped with a magnetic
stir-bar, a serum cap and an Ar inlet tube was charged
with 12.5 mg (0.50 mmol) of freshly crushed Mg powders,
10 ml of THF, 249 mg (1.0 mmol) of bis(g5-cyclopenta-
dienyl) dichlorotitanium. The mixture was stirred at r.t.
for 1–2 h until most of Mg disappeared to give a THF

2204
L.-C. Song et al. / Inorganica Chimica Acta 357 (2004) 2199–2204
[4] G. Fachinetti, C. Floriani, J. Chem. Soc. Dalton Trans. (1974)
2433.
Acknowledgements
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[5] S. Durr, U. Hohlein, R. Schobert, J. Organomet. Chem. 458
We are grateful to the National Natural Science
Foundation of China for financial support of this work.
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