5896
Organometallics 2004, 23, 5896-5899
Longitudinally Extended Molecular Wires Based upon
PtCtCCtCCtCCtC Repeat Units: Iterative Syntheses
of Functionalized Linear PtC8Pt, PtC8PtC8Pt, and
PtC8PtC8PtC8Pt Assemblies
Qinglin Zheng, Frank Hampel, and J. A. Gladysz*
Institut fu¨r Organische Chemie, Friedrich-Alexander-Universita¨t Erlangen-Nu¨rnberg,
Henkestraâe 42, 91054 Erlangen, Germany
Received August 19, 2004
Summary: Condensations of (p-tol3P)2PtCl2 with Me3-
SnCtCCtCSiMe3 and HCtCCtCSiMe3 give mono- or
bis((trimethylsilyl)butadiynyl) complexes that are de-
silylated and elaborated by oxidative cross-couplings and
homocouplings to give the title compounds trans-Cl[(p-
tol3P)2PtCtCCtCCtCCtC]mPt(P-p-tol3)2Cl (m ) 1-3).
such series are available, the gradual transition of
physical and chemical properties to the macromolecular
limit can be mapped.
In our earlier synthesis of Pt(CtC)nPt assemblies,4-7
we began with the monofunctional platinum building
blocks trans-Ar′(Ar3P)2PtCl. The chloride ligands could
easily be replaced by alkynyl ligands, and subsequent
oxidative couplings led to the target molecules. How-
ever, for the stepwise synthesis of longitudinally ex-
tended homologues, difunctional platinum building
blocks are required. One obvious choice would be the
dichloride complex (Ar3P)2PtCl2. However, at some stage
in the sequence, monofunctionalization is required.
Scouting reactions with terminal alkynes or diynes
using conditions employed previously were not promis-
ing. In all cases, mixtures of monoalkynyl, bis(alkynyl),
and unreacted complexes were obtained.
Molecules in which sp carbon chains span two transi-
tion metals have attracted great attention from both
fundamental and applied perspectives.1 Many such
wire-like compounds are now available, and researchers
are attempting to construct multidimensional arrays
that model more complex types of devices.2 Efforts in
our laboratory have focused on the elaboration of Re-
(CtC)nRe3 and Pt(CtC)nPt4-6 systems. These building
blocks are available with chain lengths of up to 20
carbons.
After some experimentation, it was found that the
unsymmetrical diyne Me3SnCtCCtCSiMe3 and (p-
tol3P)2PtCl2 (1:1 mol ratio) spontaneously condensed in
refluxing THF (Scheme 1).10 Workup gave the mono-
substituted product trans-Cl(p-tol3P)2PtCtCCtCSiMe3
(1),11 derived from Me3SnCl elimination, in 63% yield.12
The diyne was in turn easily isolated from the sequen-
tial reaction of HCtCCtCSiMe3 with n-BuLi and Me3-
SnCl.13 Perhaps this platinum-carbon bond-forming
reaction has a steric requirement greater than that of
the others investigated, giving a greater rate difference
In the previous communication, we described “bundles”
of Pt(CtC)nPt moieties (n ) 3, 4) in which the sp chains
were laterally arrayed.7 In this communication, we
report efficient syntheses of longitudinal arrays based
upon PtCtCCtCCtCCtC repeat units that contain as
many as four platinum atoms. Several polymers derived
from PtCtCCtC, PdCtCCtC, or NiCtCCtC units
have been described,8 as well as many that involve bis-
(alkynyl) arenes, MCtC-Ar-CtC.9 However, to our
knowledge iterative synthetic methodologies that yield
families of [M(CtC)n]m species remain unknown. When
(1) (a) Paul, F.; Lapinte, C. In Unusual Structures and Physical
Properties in Organometallic Chemistry; Gielen, M., Willem, R.,
Wrackmeyer, B., Eds.; Wiley: New York, 2002; pp 220-291. (b) Szafert,
S.; Gladysz, J. A. Chem. Rev. 2003, 103, 4175. (c) Bruce, M. I.; Low, P.
J. Adv. Organomet. Chem. 2004, 50, 179.
(2) (a) ALQaisi, S. M.; Galat, K. J.; Chai, M.; Ray, D. G., III; Rinaldi,
P. L.; Tessier, C. A.; Youngs, W. J. J. Am. Chem. Soc. 1998, 120, 12149.
(b) Bruce, M. I.; Costuas, K.; Halet, J.-F.; Hall, B. C.; Low, P. J.;
Nicholson, B. K.; Skelton, B. W.; White, A. H. Dalton 2002, 383.
(3) (a) Brady, M.; Weng, W.; Zhou, Y.; Seyler, J. W.; Amoroso, A. J.;
Arif, A. M.; Bo¨hme, M.; Frenking, G.; Gladysz, J. A. J. Am. Chem. Soc.
1997, 119, 775. (b) Dembinski, R.; Bartik, T.; Bartik, B.; Jaeger, M.;
Gladysz, J. A. J. Am. Chem. Soc. 2000, 122, 810. (c) Meyer, W. E.;
Amoroso, A. J.; Horn, C. R.; Jaeger, M.; Gladysz, J. A. Organometallics
2001, 20, 1115. (d) Horn, C. R.; Gladysz, J. A. Eur. J. Inorg. Chem.
2003, 9, 2211.
(4) Peters, T. B.; Bohling, J. C.; Arif, A. M.; Gladysz, J. A. Organo-
metallics 1999, 18, 3261.
(5) Mohr, W.; Stahl, J.; Hampel, F.; Gladysz, J. A. Chem. Eur. J.
2003, 9, 3324.
(6) (a) Stahl, J.; Bohling, J. C.; Bauer, E. B.; Peters, T. B.; Mohr,
W.; Mart´ın-Alvarez, J. M.; Hampel, F.; Gladysz, J. A. Angew. Chem.,
Int. Ed. 2002, 41, 1871; Angew. Chem. 2002, 114, 1951. (b) Owen, G.
R.; Stahl, J.; Hampel, F.; Gladysz, J. A. Organometallics 2004, 23, 5889.
(7) Owen, G. R.; Hampel, F.; Gladysz, J. A. Organometallics 2004,
23, 5893.
(8) (a) Takahashi, S.; Kariya, M.; Yatake, T.; Sonogashira, K.;
Hagihara, N. Macromolecules 1978, 11, 1063. (b) Sonogashira, K.;
Kataoka, S.; Takahashi, S.; Hagihara, N. J. Organomet. Chem. 1978,
160, 319. (c) Sonogashira, K.; Ohga, K.; Takahashi, S.; Hagihara, N.
J. Organomet. Chem. 1980, 188, 237. (d) Markwell, R. D.; Butler, I.
S.; Kakkar, A. K.; Khan, M. S.; Al-Zakwani, Z. H.; Lewis, J. Organo-
metallics 1996, 15, 2331.
(9) This literature is now extensive. For reviews of organometallic
polymers with transition metals in the main chain, see: (a) Nguyen,
P.; Go´mez-Elipe, P.; Manners, I. Chem. Rev. 1999, 99, 1515. (b)
Puddephatt, R. J. Chem. Commun. 1998, 1055 (feature article).
(10) Both the cis- and trans-dichloride complexes give trans substi-
tution products. The yields given are for reactions with the cis isomer,
which is the kinetic product from K2PtCl4 and p-tol3P: (a) Alt, H. G.;
Baumga¨rtner, R.; Brune, H. A. Chem. Ber. 1986, 119, 1694. (b) Matern,
E.; Pikies, J.; Fritz, G. Z. Anorg. Allg. Chem. 2000, 626, 2136.
(11) All new compounds have been characterized by microanalysis,
NMR (1H, 13C, 31P) and IR spectroscopy, and mass spectrometry, as
described in the Supporting Information.
(12) (a) Reactions of other L2PtCl2 complexes and Me3SnCtCPh give
the monosubstitution product trans-ClL2PtCtCPh in good yield:
Cardin, C. J.; Cardin, D. J.; Lappert, M. F. J. Chem. Soc., Dalton Trans.
1977, 767. (b) Many related reactions are known that require a
palladium catalyst: Lo Sterzo, C. Synlett 1999, 1704.
(13) Bunz, U. H. F.; Enkelmann, V. Organometallics 1994, 13, 3823
(see ref 14).
10.1021/om049353n CCC: $27.50 © 2004 American Chemical Society
Publication on Web 11/10/2004