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Addition of lithium chloride to a Grignard reagent breaks the polymeric aggregates producing the reactive complex 3. While the present claims are not limited by Grignard metathesis method, the magnesiate character of 3 may be responsible for the enhanced reactivity of this reagent.
This magnesiate is expected to have higher reactivity toward electrophiles, such as nickel phosphine catalysts. Metal halogen exchange, in particular bromine-magnesium exchange, is known in the art. See for example Loewe et al.
The metal halogen exchange reaction can be characterized by: This reaction generally has been used less than counterpart organolithium reactions.
However, the reaction can be used for aryl and heteroaryl bromides and iodides. Presently, the reaction is more broadly used in polymer chemistry than heretofore possible to form conjugated polymers.
Presently, a variety of conjugated polymers can be prepared by the methods herein including for example polyfluorenes, polypyrroles, poly phenylenesand polythiophenes, as well as derivatives, homopolymers, and copolymers thereof.
Another example are the polycarbazoles including derivatives, homopolymers, and copolymers thereof. The reaction should be fast enough to be commercially realistic. Unsaturated Ring Compound A wide variety of unsaturated ring compounds can be used.
In particular, unsaturated ring compounds can be used which are difficult to polymerize in the GRIM process heretofore known using unmodified or unactivated organomagnesium reagents.
Certain aryl and heteroaryl halides for example are relatively unreactive in the magnesium halogen exchange process, which can prevent use of the GRIM method.
In addition, unsaturated ring compounds can be used which are useful in the synthesis of conjugated polymers. They can provide multiple alternating single and double bonds which provide for extended conjugation, particular when monomer or dimer units are connected by carbon-carbon bonds during polymerization.
A variety of embodiment can be used. For example, the unsaturated ring compound can comprise at least one aromatic or pseudo-aromatic ring.
The unsaturated ring compound can comprise one or two rings, wherein the rings are five or six membered rings. The unsaturated ring compound can be a heterocyclic ring compound. For example, the ring or rings can comprise all carbon atoms except for one heteroatom such as for example nitrogen or sulfur.
Alternatively, the unsaturated ring compound can be a non-heterocyclic ring compound. The ring or rings can comprise all carbon atoms. The unsaturated ring compound can comprise a single heterocyclic ring, a single aromatic ring, or a single bi-phenyl ring system.
The unsaturated ring compound can comprise two halogen atoms which are bonded to carbon ring atoms which are not adjacent to each other. For example, the carbon ring atoms can be separated from each other by a heteroatom such as sulfur or nitrogen, or by one or more carbon atoms.
The unsaturated ring compound can comprise two rings, wherein each ring comprises a halogen ring substituent. In particular, the unsaturated ring compound can be a thiophene compound, a pyrrole compound, or a fluorene compound.
Other examples include a carbazole compound or a phenyl compound.Oct 16, · McCullough et al. Grignard Metathesis Method (GRIM): Toward a Universal Method for the Synthesis of Conjugated Polymers. Macromolecules, , 42, Iraqi (Preparation of poly(9-alkylcarbazole-3,6-diyl)s via palladium catalysed cross-coupling reactions.
Synthetic Metals, , , pp. . Grignard Metathesis Method (GRIM): Toward a Universal Method for the Synthesis of Conjugated Polymers. at least three reasons why the Grignard metathesis (GRIM) method is useful in the synthesis of semiconducting polymers. P3ATs are an Important Class of Organic Electronic Materials.
Using a modified Grignard metathesis (GRIM) reaction, a series of polymers have been synthesized bearing functional groups on one or both ends of the polymer. Koji Takagi, Hyunho Joo, Yusuke Yamashita, Eiki Kawagita and Chikako Torii, Regioselective grignard metathesis reaction of 2,5‐dibromo‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene and kumada coupling polymerization, Journal of Polymer Science Part A: Polymer Chemistry, 49, 18, (), ().
An example of the Grignard reaction is a key step in the In-Situ End-Group Functionalization of Regioregular Poly(3 In-Situ End-Group Functionalization of Regioregular Poly(3-alkylthiophene) Using the Grignard Metathesis Polymerization Method The McCullough Group – Publications Publications Recent publications: quot;Experimental Evidence for.