Synthesis of Zirconocene-Acetylene and Zirconocene-
Diacetylene Polymer
PRAFULLA K. SAHOO, SARAT K. SWAIN
Department of Chemistry, Utkal University, Vani Vihar, Bhubaneswar-751 004, India
Received 16 February 1999; accepted 12 May 1999
ABSTRACT: A new class of organometallic polymer having a backbone of conjugated
Poly-yne and Zr-metal atoms has been prepared. Trichloroethylene (TCE) and Hexa-
chlorobutadiene (HCB) are quantitatively converted by n-butyllithium to dilithioacety-
lene (LiC'CLi) and dilithiodiacetylene (LiOC'COC'COLi) respectively. Quenching
with Cp
2
*ZrCl
2
affords high yields of the polymers [ -Zr(Cp
2
*)C'C] -
n
and
[ -Zr(Cp
2
*)C'COC'C] -
n
where Cp* = C
5
(CH
3
)
5
= pentamethyl cyclopentadienyl. The
Cp
2
*ZrCl
2
and the polymers were characterized by viscosity, molecular weight, elemen-
tal analysis, FTIR, NMR spectra, and TGA. © 1999 John Wiley & Sons, Inc. J Polym Sci A:
Polym Chem 37: 3899 –3902, 1999
Keywords: Zirconocene; acetylene; diacetylene polymers; TGA
INTRODUCTION
One of the current interests in polymer chemistry
lies in organometallic polymers, whose metal cen-
tres are joined by organic ligands with delocalized
-systems, due to their potential applications in
areas of electronics and material science.
1–5
The
main aim of the topic is to introduce metal atoms
and metal containing moieties into polymer back-
bone in known positions as described by Carraher
and coworkers.
6–8
The research area of Zr-con-
taining polymers is important and there is much
current interest in this area. Now the efficient
‘one-pot’ synthesis of zirconium containing poly-
mers with structure 2 and 3 are reported.
Bis(pentamethylcyclopentadienyl) zirconium di-
chloride (Cp
2
*ZrCl
2
) was selected as the Group
IVB containing reactant for several reasons. Com-
pounds containing the Cp
2
M/Cp
2
*M moiety (M
= Fe, Ti, Zr, Hf) are reported to be stabilizers to
UV radiation. Studies on poly-yne polymers con-
taining transition metals and main group ele-
ments in the main chain have been carried out by
Hagihara et al. (platinum),
9
Barton and cowork-
ers,
10,11
and Ishikawa et al. (silicon).
12
The mag-
netic anisotropy of these polymers may be con-
trolled by incorporating different transition metal
atoms in the polymer backbone.
13,14
This paper now reports the first preliminary
example of the synthesis of the zirconocene poly-
yne polymers, and to our knowledge this also
represents the first example of the metal poly-yne
polymer containing cyclopentadiene substituents
with a view to their special properties.
15
EXPERIMENTAL
All reactions and purifications were performed
under an atmosphere of dry N
2
using Schlenk
techniques. All the solvents used were freshly
distilled under N
2
from drying agents. All other
reagents were purchased from Aldrich and puri-
fied by standard methods.
IR spectra were obtained with a Nicolet 5-DX
FT-IR spectrometer, using solutions in suitable
solvents or KBr pellets.
1
H-NMR spectra were
recorded on a Bruker WM 360 MHz spectrometer.
Correspondence to: P. K. Sahoo
Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 37, 3899 –3902 (1999)
© 1999 John Wiley & Sons, Inc. CCC 0887-624X/99/213899-04
3899