C–H Functionalization Polycondensation of Chlorothiophenes in the Presence of Nickel Catalyst with Stoichiometric or Catalytically Generated Magnesium Amide

The attractive optoelectronic properties of conducting polymers depend sensitively upon intra-and inter-polymer chain interactions, and therefore new methods to manipulate these interactions are continually being pursued. Here, we report a study of the isotopic effects of deuterium substitution on the structure, morphology and optoelectronic properties of regioregular poly(3-hexylthiophene)s with an approach that combines the synthesis of deuterated materials, optoelectronic properties measurements, theoretical simulation and neutron scattering. Selective substitutions of deuterium on the backbone or side-chains of poly(3-hexylthiophene)s result in distinct optoelectronic responses in poly(3-hexylthiophene)/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) photovoltaics. Specifically, the weak non-covalent intermolecular interactions induced by the main-chain deuteration are shown to change the film crystallinity and morphology of the active layer, consequently reducing the short-circuit current. However, side-chain deuteration does not significantly modify the film morphology but causes a decreased electronic coupling, the formation of a charge transfer state, and increased electron-phonon coupling, leading to a remarkable reduction in the open circuit voltage.

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“…The synthesis of rr-P3HT is referred to previous publication 46 . The synthetic route of deuterated P3HT was shown in Supplementary Fig.…”

Section: Methodsmentioning

confidence: 99%

The isotopic effects of deuteration on optoelectronic properties of conducting polymers

et al. 2014

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“…As a result, catalyst association during the polymerization can be determined indirectly by investigating the effect of purposely added transfer reagent. 15,22 Another way of determining catalyst association is by using a model coupling reaction between a monomer with organometallic entities and an aryl halide, in which a competition between inter-and intramolecular pathways is present; if catalyst association is present, the main products should be formed by intramolecular reactions. 10,12,13,23,24 Direct confirmation of the formation of an associated complex is not as straightforward, since in this case this species needs to be identified as the catalyst resting state to enable direct measurement thereof.…”

Section: ■ Introductionmentioning

confidence: 99%

“…15,46,47 This catalyst system has also shown to polymerize through catalyst association, by yielding high molecular weights with no clear dependence on transfer agents (nonconverted monomer). 15 Furthermore, the reactivity of this catalyst system has proven to differ significantly from other Nicatalysts, which is reflected by a clear increase in reactivity toward thiophene with a Cl-atom instead of a Br-atom in the 2-position, in comparison with Ni(dppe)Cl 2 . This difference in reactivity, however, had no effect on the polymerization of 2: the Ni(NHC)-complex did not succeed in forming any polymeric material.…”

Section: ■ Introductionmentioning

confidence: 99%

Evidence for Catalyst Association in the Catalyst Transfer Polymerization of Thieno[3,2-b]thiophene

Willot

Koeckelberghs

2014

Macromolecules

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The performance of catalyst transfer polymerization (CTP) reactions which depend on catalyst association was studied on 3,6-dioctylthiothieno[3,2-b]thiophene (TT)-monomers. This monomer was selected because a strong association of the catalyst is expected, since the aromaticity of thienothiophene is largely maintained when the catalyst and thienothiophene associate. This study includes both reported and unreported Ni-and Pd-catalyst systems. It is found that no polymer formation can be observed using Ni-catalysts, whereas Pd-catalysts show a similar behavior as for other monomer systems. During the study of the Ni-catalyzed CTPs, the π-associated Ni 0 -complex has been isolated in situ and displayed a high stability in solution. It is shown that the associated complex interferes with the polymerization reaction and even prevents polymer formation. Furthermore, this complex prevented any Kumada-coupling reaction in the presence of the TT unit, as it serves as a "trapping site" for free Ni 0 -catalyst entities. Ni 0 -trapping does not occur during polymerization of 3-alkylthiophene, confirming the presence of the π-associated Ni 0 -complex in this polymerization. This introduces a new convenient method of probing Ni 0 -association during all Ni-catalyzed reactions. Furthermore, these results establish the presence of an upper limit to the catalyst association strengthabove which oxidative addition is prevented and the polymerization is inhibitedand they therefore add extra considerations for optimal catalyst design.

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“…Because the obtained polymer was hardly soluble in CHCl 3 , SEC analysis was performed at 140 1C using o-dichlorobenzene as an eluent. When the catalyst was switched to NiCl 2 (PPh 3 )IPr (IPr: 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), which showed excellent catalytic activity during the polymerization of 2-chloro-3-hexylthiophene, 24 polymer 5 was obtained with a 48% yield and low molecular weight (M n ¼ 4470). The similar reaction with Pd-PEPPSI-SIPr (pyridine-enhanced precatalyst preparation stabilization and initiation-1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene) 33 afforded 5 with a 35% yield and M n ¼ 5190.…”

Section: Resultsmentioning

confidence: 99%

“…21,22 This method enables the polymerization to occur at lower reaction temperatures within shorter polymerization times. [23][24][25] During the course of our studies, our interest has been focused on extending the available monomer species. We herein describe the C-H functionalization polymerization of 2-(4-haloarylated)thiophene derivatives, leading to the synthesis of the corresponding formal alternating copolymer poly(thienylene-alt-arylene) and that of monobrominated benzodithiophene to afford poly(benzodithiophene) (Scheme 1).…”

mentioning

confidence: 99%

Synthesis of π-conjugated poly(thienylenearylene)s with nickel-catalyzed C–H functionalization polycondensation

Tamba

Okubo

Sugie

et al. 2012

Polym J

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p-Conjugated polymers are synthesized by C-H and C-X polycondensation of 2-(4-haloaryl)thiophene monomers with a nickel catalyst, and the Knochel-Hauser base (TMPMgCl . LiCl (chloromagnesium 2,2,6,6-tetramethylpiperidide lithium chloride salt)). The C-H functionalization polycondensation reaction of a monobrominated monomer undergoes dehydrobrominative polymerization with an equimolar amount of TMPMgCl . LiCl and a catalytic amount of NiCl 2 dppp to produce poly(2,5-thienylene-1,4-phenylene) and poly(2,5-thienylenepyridine-2,5-diyl) with reasonable yields. Polycondensation with triflate as a leaving group proceeds under similar conditions to produce poly(thienylenephenylene) with an excellent yield. Poly(benzodithiophene) was also obtained from the reaction of the corresponding monobrominated benzodithiophene in the presence of a nickel-catalyst-bearing N-heterocyclic carbene as a ligand.

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C–H Functionalization Polycondensation of Chlorothiophenes in the Presence of Nickel Catalyst with Stoichiometric or Catalytically Generated Magnesium Amide

Cited by 159 publications

References 75 publications

The isotopic effects of deuteration on optoelectronic properties of conducting polymers

The isotopic effects of deuteration on optoelectronic properties of conducting polymers

Evidence for Catalyst Association in the Catalyst Transfer Polymerization of Thieno[3,2-b]thiophene

Synthesis of π-conjugated poly(thienylenearylene)s with nickel-catalyzed C–H functionalization polycondensation

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