Journal of Organometallic Chemistry 580 (1999) 210 – 213
A directly ring-to-ring linked ferrocene – pseudotitanocene complex
Petr S te ˘pnic ka
a
, Jaroslav Podlaha
a
, Michal Hora ´c ek
b
, Vladimı ´r Hanus
b
, Karel Mach
b,
*
a
Department of Inorganic Chemistry, Faculty of Nature Sciences, Charles Uniersity, Hlaoa 2030, Prague 2, Czech Republic
b
J. Heyrosky ´ Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejs koa 3, 182 23 Prague 8, Czech Republic
Received 1 October 1998
Abstract
Addition of excess ferrocenylacetylene (FcCCH) to [
5
-(C
5
H
5
)Ti][:
2
:
2
-C
2
(SiMe
3
)
2
]
2
[
5
-(C
5
H
5
)Mg] (1) affords the novel
ferrocene – pseudotitanocene complex [
5
-1,2,5,6-tetrakis(trimethylsilyl)-4-ferrocenylcyclohexa-1,4-dienyl](
5
-cyclopentadienyl)-
titanium(II), [
5
-(Me
3
Si)
4
FcC
6
H
2
]Ti(
5
-C
5
H
5
)(2), as the sole isolated titanium-containing product. Its structure was established
by EI MS, NMR and UV–vis spectroscopy. The formation of 2 follows the general reaction route of terminal acetylenes with 1.
© 1999 Elsevier Science S.A. All rights reserved.
Keywords: Titanium(II); Ferrocene – pseudotitanocene complex; Ferrocenylacetylene; Cyclopentadienyl – cyclohexadienyl bond;
NMR spectra
1. Introduction
Looking for synthetic methods leading to
organometallic compounds containing two or more
metal atoms linked by a hydrocarbon chain, two main
methods become obvious. Firstly, the direct use of a
functionalized organometallic compound as the ligand
in transition metal complexes and secondly, a synthetic
transformation of an organometallic compound (its
substituents) into a new compound. In the case of
ferrocene derivatives, the first route may be docu-
mented by many syntheses and applications of com-
plexes with ferrocene-based ligand such as phosphines,
mixed P,N -donors etc. reported in the literature [1]. As
for the application of the second approach in the
chemistry of ferrocenes, ethynylferrocene [2] is a fre-
quently used, extremely versatile starting compound.
One straightforward method for transformation of its
triple bond into a linking group is the simple deproto-
nation of ethynylferrocene yielding -complexes of the
M–CCFc (Fc =ferrocenyl) type [3]. The formation of
carbenes MC(R)CH
2
Fc (M =Ru [4]) or vinylidene
complexes MCCFc(R) (M =Rh [5]) might serve as
another example. Application of derivatives containing
a spacer between ferrocenyl and ethynyl groups further
increases the scope of accessible complexes [6,7]. In
spite of a variety of synthetic tools, however, the com-
binations of early and late transitions metals are rather
rare [8]. For titanium, the following titanocene
bis(acetylide) complexes have been reported so far:
(
5
-C
5
H
4
(SiMe
3
)]
2
Ti(
1
-CCFc)
2
, its tweezer complex
with an embedded Ni(CO) group [9] and (
5
-
C
5
H
5
)
2
Ti(
1
-CCCCFc)
2
[10]. We have used ethynyl-
ferrocene to mimic the reaction of terminal acetylenes
with the titanium – magnesium complex [
5
-(C
5
H
5
)-
Ti][:
2
:
2
-C
2
(SiMe
3
)
2
]
2
[
5
-(C
5
H
5
)Mg] (1) [11]. In this
reaction a terminal acetylene takes part in the forma-
tion of a tetrakis(trimethylsilyl)-substituted cyclohexa-
dienyl ligand affording the corresponding (
5
-
cyclohexadienyl)(
5
-cyclopentadienyl)titanium(II) com-
plex (Scheme 1) [12].
* Corresponding author. Tel.: +42-2-858-5367; fax: +42-2-858-
2307.
E-mail address: mach@jh-inst.cas.cz (K. Mach)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII:S0022-328X(98)01147-4