Grignard Metathesis Method (GRIM): Toward a Universal Method for the Synthesis of Conjugated Polymers

Abstract

Materials. Lithium chloride, lithium t-butoxide, isopropyl magnesium chloride (2M in THF), t-butyl magnesium chloride (2M in diethyl ether), n-butyl magnesium chloride (2M in THF), n-butyl lithium (1.6 M in hexane), and 9,9-dioctyl-2,7-dibromofluorene were purchased from Aldrich and used as received. Tetrahydrofuran was distilled from sodium benzophenone ketyl and collected over molecular sieves. n-Bu 3 MgLi was synthesized in anhydrous toluene at -10 0 C as previously reported.Synthesis of RMgCl.LiX (R = i-Pr or t-Bu; X = Cl or t-BuO). A dry 50 mL three-neck flask was flushed with nitrogen and was charged with a 2M solution of i-PrMgCl in THF (2.5 mL, 5 mmol) and 5 mL of anhydrous THF. Lithium salt (5 mmol) was added to the reaction flask under nitrogen. The reaction mixture was stirred for 6-8 hrs at room temperature.General synthesis of polymers using i-PrMgCl•LiCl as reagent for magnesium halogen exchange. A solution of dibrominated monomer (5 mmol) in 5 mL of anhydrous THF was added under nitrogen to the previously prepared solution of i-PrMgCl•LiCl (5 mmol). The reaction mixture was stirred at room temperature, and monitored by GC-MS.Analysis of the reaction mixture confirmed the formation of monoGrignard reagent in at least 85 % yield. Ni(dppp)Cl 2 (0.02 g, 0.04 mmol) was added to the reaction mixture dissolved in 10 mL anhydrous THF. The polymerization was allowed to proceed for 2-48 h at room temperature followed by quenching of the reaction mixture with methanol.The precipitated polymer was filtered through a thimble and subjected to methanol extraction. The polymer was dried under vacuum for 12 hrs.

Recent advances in conjugated polymer energy storage

“…58,88,89 Metal-catalyzed cross-couplings are another method for producing conjugated polymers. [90][91][92][93][94] Unlike oxidative synthesis, polymers synthesized in this way are formed in a charge-neutral state. Unfortunately, these systems can sometimes require the presence of specific functional groups and sensitive reaction conditions not conducive to producing large quantities of material suitable for electrodes.…”

Synthesis of poly(thiophene-alt-pyrrole) from a difunctionalized thienylpyrrole by Kumada polycondensation

“…This problem has been reported for other polymers, such as poly(9,9-dioctyfluorene). 49 In that case, the use of the magnesium complex [tBuMgCl·LiCl·15-crown-5] as the metallating species prevented any further substitution most likely because the tert-butyl cation is more stable compared to isopropyl cation. Treatment of 4 with 1 equiv of [tBuMgCl·LiCl·15-crown-5] at 20 °C for 10 min in THF gave 7 (100% yield based on analytical GC-MS with analysis of the protonated species 3).…”

The effect of intramolecular donor–acceptor moieties with donor–π-bridge–acceptor structure on the solar photovoltaic performance

“…However, it was found that yields of this series of copolymer were relatively low. Hence, it is suggested that for the synthesis of this series of copolymers, other Grignard regents such as isopropylmagnesium chloride (i-PrMgCl) or isopropylmagnesium bromide (i-PrMgBr) together with lithium chloride (LiCl) may be used to afford the copolymers in good yields [29,30]. Since the copolymer synthesized by Wei's group comprising of equal molar ratio of M1!…”