End-Group-Mediated Aggregation of Poly(3-hexylthiophene)

Fronk, Stephanie L.; Mai, Cheng‐Kang; Ford, Michael J.; Noland, Ryan P.; Bazan, Guillermo C.

doi:10.1021/acs.macromol.5b00986

Cited by 17 publications

(12 citation statements)

References 86 publications

(50 reference statements)

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“…was synthesized in the same way. 53 Pammer et al were able to polymerize thiazole monomers with initiators 18 and 19, which were made by the sequential addition of PPh3, the desired aryl bromide and dppp to Ni(COD)2. 54 The last method is based on the one-step reaction of Ni(dppp)2 with an aryl bromide, rendering (Ar)Ni(dppp)Br.…”

Section: External Initiatorsmentioning

confidence: 99%

Advances in the controlled polymerization of conjugated polymers

Verheyen

Leysen

Eede

et al. 2017

Polymer

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This article features recent advances in the synthesis of conjugated polymers via a controlled polymerization. These polymerizations typically rely on transition metal catalyzed cross coupling reactions. The mechanisms of the polymerization protocols are discussed in detail. An overview of all possible protocols and all homopolymers that have been investigated is given. Next, the synthesis of copolymers-random, gradient and block copolymers-is reviewed. Another advantage of a controlled polymerization is the possibility to introduce specific functional groups, either at the beginning of each polymer chain by the use of an external initiator, or at the end of the polymer chain using an endcapper. Finally, topologies different from simple linear polymer chains are discussed. This feature article is complementary to other recent review articles on this topic. 1,2

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Section: External Initiatorsmentioning

confidence: 99%

Advances in the controlled polymerization of conjugated polymers

Verheyen

Leysen

Eede

et al. 2017

Polymer

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“…In addition, the reactive ligand can be used to selectively functionalize one chain end for postpolymerization use. 67 Precatalysts containing reactive ligands can be prepared either by aryl halide oxidative addition with Ni(0) or by reacting Ni(II) precursors with an organometallic reagent; however, in many cases a subsequent ligand exchange reaction is necessary to generate the desired precatalyst. 66,68,69 The alternative one-step approach involves reacting aryl Grignard reagents directly with a dihalide precatalyst already containing the ancillary ligand.…”

Section: Reactive Ligandmentioning

confidence: 99%

Matchmaking in Catalyst-Transfer Polycondensation: Optimizing Catalysts based on Mechanistic Insight

2016

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Catalyst-transfer polycondensation (CTP) has emerged as a useful living, chain-growth polymerization method for synthesizing conjugated (hetero)arene-based polymers with targetable molecular weights, narrow dispersities, and controllable copolymer sequences-all properties that significantly influence their performance in devices. Over the past decade, several phosphine- and carbene-ligated Ni- and Pd-based precatalysts have been shown to be effective in CTP. One current limitation is that these traditional CTP catalysts lead to nonliving, non-chain-growth behavior when complex monomer scaffolds are utilized. Because these monomers are often found in the highest-performing materials, there is a significant need to identify alternative CTP catalysts. Recent mechanistic insight into CTP has laid the foundation for designing new catalysts to expand the CTP monomer scope. Building off this insight, we have designed and implemented model systems to identify effective catalysts by understanding their underlying mechanistic behaviors and systematically modifying catalyst structures to improve their chain-growth behavior. In this Account, we describe how each catalyst parameter-the ancillary ligand(s), reactive ligand(s), and transition metal-influences CTP. As an example, ancillary ligands often dictate the turnover-limiting step of the catalytic cycle, and perhaps more importantly, they can be used to promote the formation of the key intermediate (a metal-arene associative complex) and its subsequent reactivity. The fidelity of this intermediate is central to the mechanism for the living, chain-growth polymerization. Reactive ligands, on the other hand, can be used to improve catalyst solubility and accelerate initiation. Additional advantages of the reactive ligand include providing access points for postpolymerization modification and synthesizing polymers directly off surfaces. While the most frequently used CTP catalysts contain nickel, palladium-based catalysts exhibit a higher functional group tolerance and broader substrate scope (e.g., monomers with boron, magnesium, tin, and gold transmetalating agents). Overall, we anticipate that applying the tools and lessons detailed in this Account to other monomers should facilitate a better "matchmaking" process that will lead to new catalyst-transfer polycondensations.

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“…The polymerization was quenched with ethylmagnesium bromide to provide P3HT-3 with a number-average molecular weight, M n , of 7.1 and 11.8 kDa and a dispersity, Đ , of 1.3 and 1.4 for 40:1 and 80:1 monomer-to-catalyst ratios, respectively. The identity of the end groups was confirmed by 1 H nuclear magnetic resonance (NMR) spectroscopy and matrix-assisted laser desorption/ionization–time-of-flight (MALDI-TOF) mass spectrometry using an analysis method described previously (see the Supplementary Materials) ( 30 , 31 ).…”

Section: Resultsmentioning

confidence: 99%