Polymerization of Acetylenes

Metathesis Polymerization Reactions Induced by the Bimetallic Complex (Ph4P)2[W2(μ-Br)3Br6]

“…We have already reported that the ditungsten complex Na[W 2 (µ-Cl) 3 Cl 4 (THF) 2 ]¨(THF) 3 (2, {W 3 W} 6+ , a 12 e 14 ) is a highly efficient and stereoselective room temperature homogeneous and/or heterogeneous initiator for metathesis polymerization of alkynes [18] and ROMP of norbornene (NBE) and some of its derivatives [19]. That complex acts as a unicomponent initiator in most cases.…”

“…In view of exploring the potential catalytic reactivity of multiply-bonded transition metal complexes and establishing efficient, robust and stereoselective catalytic systems for metathesis polymerization reactions, we report a study of the reactivity of the perbromo-complex (Ph 4 P) 2 [W 2 (µ-Br) 3 Br 6 ] (1, {W 2.5 W} 7+ , a 12 e 13 ) towards the ROMP of NBE and some of its derivatives, as well as towards the mechanistically-related polymerization of PA. 1 is easily accessible, moderately air-stable, bears labile ligands and higher nuclear charge compared to 2. Our results show that addition of a silver salt (AgBF 4 ) is required in order to activate the ditungsten complex.…”

“…(Ph 4 P)[W(CO) 5 Br] [21] and (Ph 4 P) 2 [W 2 (µ-Br) 3 Br 6 ] (1) [22] were prepared according to literature procedures. For the synthesis of both compounds, Ph 4 PBr was used instead of n Pr 4 NBr.…”

“…Among them, metathesis polymerization of alkynes [1][2][3] and ring opening metathesis polymerization (ROMP) of cycloolefins [4][5][6] yield unsaturated polymeric materials and are considered as two of the most important tools in polymer chemistry, leading to the synthesis of novel materials (Scheme 1). The properties of these polymers sensitively depend on their microstructure.…”

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Abstract:The reactivity of the bimetallic complex (Ph 4 P) 2 [W 2 (µ-Br) 3 Br 6 ] ({W 2.5 W} 7+ , a 12 e 3 ) towards ring opening metathesis polymerization (ROMP) of norbornene (NBE) and some of its derivatives, as well as the mechanistically related metathesis polymerization of phenylacetylene (PA), is presented. Our results show that addition of a silver salt (AgBF 4 ) is necessary for the activation of the ditungsten complex.

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