Durch oberflächeninitiierte Suzuki‐Polykondensation zu gepfropftem Polyfluoren

Beryozkina, Tetyana; Boyko, Ksenia; Khanduyeva, Natalya; Senkovskyy, Volodymyr; Horecha, Marta; Oertel, Ulrich; Simon, Frank; Stamm, Manfred; Kiriy, Anton

doi:10.1002/ange.200806217

Cited by 7 publications

(1 citation statement)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[12] To date, chain-growth polymerisations are restricted to the obtainment of polyA C H T U N G T R E N N U N G (arylene)s and have been reported for Ni-catalysed Kumada cross-couplings [13] and for Pd-catalysed Suzuki-Miyaura reactions. [14] In these cases, the chain propagation proceeds through the successive addition of AB-type monomers promoted by a catalyst-transfer polycondensation mechanism in which the catalyst, after the activation of the C À Br bond at the chain end, followed by reaction with the monomer, reaches the end of the newly elongated polymer by a so-called "ring-walking" process [15] Abstract: The mechanism of the Suzuki-Heck (SuHe) polymerisation of 2,7-dibromo-9,9-di(n-dodecyl)fluorene (1) with potassium vinyl trifluoroborate (PVTB) for the synthesis of poly(fluorenylene vinylene)s (PFVs) has been investigated. In the first stage, a palladium-catalysed chain-growth AA/B(C)type polycondensation occurs, as evidenced by the linear trend observed when plotting the molecular weights of the polymer formed against the consumption of the monomer.…”

Section: Introductionmentioning

confidence: 99%

Chain‐Growth Versus Step‐Growth Mechanisms for the Suzuki–Heck Polymerisation of Fluorenyldibromides with Potassium Vinyl Trifluoroborate

Grisorio

Suranna

Mastrorilli

2010

Chemistry A European J

View full text Add to dashboard Cite

The mechanism of the Suzuki-Heck (SuHe) polymerisation of 2,7-dibromo-9,9-di(n-dodecyl)fluorene (1) with potassium vinyl trifluoroborate (PVTB) for the synthesis of poly(fluorenylene vinylene)s (PFVs) has been investigated. In the first stage, a palladium-catalysed chain-growth AA/B(C)-type polycondensation occurs, as evidenced by the linear trend observed when plotting the molecular weights of the polymer formed against the consumption of the monomer. The chain-growth stage takes place until complete consumption of 1 and allows one to envisage the alternating addition of PVTB (by a Suzuki step) and 1 (by a Heck step) to the growing chain. Such alternating addition seems to proceed through a peculiar catalyst transfer during which the metal is constantly bound to the growing chain, confirmed by MALDI end-group analysis. On prolonging the reaction after the disappearance of 1, a second stage takes place, leading to higher molecular weight polymers, which are formed by the step-growth condensation of the fragments generated in the first stage. The molecular weights of the final PFVs depend on the PVTB/1 feed ratio. Thus, by using a PVTB/1 molar ratio of 1.1, the final PFV was characterised by an M(n) of 39600 Da, whereas when using a PVTB/1 molar ratio of 2.0, the final PFV was characterised by an M(n) of 13200 Da.

show abstract

Section: Introductionmentioning

confidence: 99%

Chain‐Growth Versus Step‐Growth Mechanisms for the Suzuki–Heck Polymerisation of Fluorenyldibromides with Potassium Vinyl Trifluoroborate

Grisorio

Suranna

Mastrorilli

2010

Chemistry A European J

View full text Add to dashboard Cite

show abstract

Intramolecular Catalyst Transfer over Sterically Hindered Arenes in Suzuki Cross‐Coupling Reactions

Zhu

Shen

et al. 2019

Asian J Org Chem

View full text Add to dashboard Cite

The intramolecular catalyst transfer over sterically hindered arenes in Suzuki cross-coupling reaction was investigated by the reaction of ortho-substituted dibromoarenes with equimolar ortho-substituted phenylboronic acid in the presence of NHC based PEPPSI-IPr as catalyst. The diarylarene species of the form Ar'À ArÀ Ar' were observed as major product, which suggested the intramolecular transfer of Pd(0) over sterically hindered arenes proceeded smoothly in Suzuki cross-coupling reaction. Furthermore, our studies also demonstrated that intramolecular catalyst transfer could be a useful tool to improve the polymerization efficiency, especially in the synthesis of ortho-linked polyarenes.

show abstract

Palladium‐Catalyzed Chain‐Growth Polycondensation of AB‐type Monomers: High Catalyst Turnover and Polymerization Rates

Tkachov

Senkovskyy²,

Beryozkina

et al. 2014

Angewandte Chemie

Self Cite

View full text Add to dashboard Cite

Chain-growth catalyst-transfer polycondensations of AB-type monomers is a new and rapidly developing tool for the preparation of well-defined p-conjugated (semiconducting) polymers for various optoelectronic applications. Herein, we report the Pd/PtBu 3 -catalyzed Negishi chain-growth polycondensation of AB-type monomers, which proceeds with unprecedented TONs of above 100 000 and TOFs of up to 280 s À1 . In contrast, related AA/BB-type step-growth polycondensation proceeds with two orders of magnitude lower TONs and TOFs. A similar trend was observed in Suzuki-type polycondensation. The key impact of the intramolecular (vs. intermolecular) catalyst-transfer process on both polymerization kinetics and catalyst lifetime has been revealed.p-C onjugated (semiconducting) polymers have become an important class of materials for applications in polymer solar cells, field-effect transistors, and light emitting diodes. [1] p-Conjugated polymers are generally produced by step-growth polymerizations, most often by Pd-catalyzed Stille [2] and Suzuki [3] polycondensations with the so-called AA/BB approach. [4] p-Conjugated polymers synthesized in such a way frequently suffer from a low degree of control over molecular weight (MW) which is undesirable for optoelectronic applications. Another drawback of step-growth Stille and Suzuki polycondensations is that they are relatively slow processes because of the moderate nucleophilicity of tin-and boron-organics. With these methods, synthesis of high MW polymers (which are especially attractive for applications) [5] usually requires long reaction times, high temperatures, and high loadings of expensive Pd catalysts. [2] The formation of toxic byproducts is another drawback inherent to Stille polycondensation. On the other hand, Negishi type polycondensation, which utilizes non-toxic and strongly nucleophilic zinc-organic-based monomers, is a promising technique for industrial-scale production. [6] Impressive progress was achieved in the last decade in the development of new, more efficient Pd catalysts for cross-couplings of small molecules. [6] Particularly, it was demonstrated that the use of bulky and electron-rich ligands enables, in many cases, cross-couplings to proceed under mild conditions, with low catalyst loadings and involving otherwise inactive electrophiles. [7] Turnover numbers (TONs) [8] above 100 000 where demonstrated in Suzuki, Negishi, and Heck cross-couplings, making them attractive for commercial applications. [9] Surprisingly, mechanistically related polycondensations underwent little improvement since their discovery. [2,3] Chain-growth catalyst-transfer polycondensations of ABtype monomers is a new and rapidly developing alternative for the preparation of well-defined conjugated homo-, gradient-, and block-copolymers. [10] Unlike the situation with step-growth polycondensations, promising results were achieved in chain-growth polycondensations initiated by newgeneration catalysts. [10][11][12] Particularly, it was shown that Pd/ PtBu 3 is an efficient in...

show abstract

Durch oberflächeninitiierte Suzuki‐Polykondensation zu gepfropftem Polyfluoren

Cited by 7 publications

References 31 publications

Chain‐Growth Versus Step‐Growth Mechanisms for the Suzuki–Heck Polymerisation of Fluorenyldibromides with Potassium Vinyl Trifluoroborate

Chain‐Growth Versus Step‐Growth Mechanisms for the Suzuki–Heck Polymerisation of Fluorenyldibromides with Potassium Vinyl Trifluoroborate

Intramolecular Catalyst Transfer over Sterically Hindered Arenes in Suzuki Cross‐Coupling Reactions

Palladium‐Catalyzed Chain‐Growth Polycondensation of AB‐type Monomers: High Catalyst Turnover and Polymerization Rates

Contact Info

Product

Resources

About