Nickel Catalyst with a Hybrid P, N Ligand for Kumada Catalyst Transfer Polycondensation of Sterically Hindered Thiophenes

Schiefer, Daniel; Wen, Tao; Wang, Yingying; Gérard, Pierre; Komber, Hartmut; Hanselmann, Ralf; Braunstein, Pierre; Reiter, Günter; Sommer, Michael

doi:10.1021/mz500282j

Cited by 24 publications

(48 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Materials. To synthesize PDOPT with a defined molecular weight, low dispersity, and high regioregularity, a Kumada catalyst-transfer polycondensation including a nickel catalyst with a hybrid P,N ligand was used (21). P3HT was synthesized via catalyst transfer polymerization (66).…”

Section: Methodsmentioning

confidence: 99%

“…We combine single-molecule low-temperature photoluminescence (PL) spectroscopy with quantum-classical atomistic simulations to investigate two polythiophenes with defined molecular weight and high regioregularity but different substitution patterns ( Fig. 1 D-F, Insets): First, poly(3-(2,5-dioctylphenyl)thiophene) (PDOPT) with sterically very demanding 2,5-dioctylphenylene side-chains, which prevent direct π−π interaction of neighboring backbones (20,21). Second, the prototypical poly(3-hexylthiophene) (P3HT) with relatively short hexyl side groups.…”

Section: Significancementioning

confidence: 99%

See 1 more Smart Citation

Direct observation of backbone planarization via side-chain alignment in single bulky-substituted polythiophenes

Raithel

Simine

Pickel

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

The backbone conformation of conjugated polymers affects, to a large extent, their optical and electronic properties. The usually flexible substituents provide solubility and influence the packing behavior of conjugated polymers in films or in bad solvents. However, the role of the side chains in determining and potentially controlling the backbone conformation, and thus the optical and electronic properties on the single polymer level, is currently under debate. Here, we investigate directly the impact of the side chains by studying the bulky-substituted poly(3-(2,5-dioctylphenyl)thiophene) (PDOPT) and the common poly(3-hexylthiophene) (P3HT), both with a defined molecular weight and high regioregularity, using low-temperature single-chain photoluminescence (PL) spectroscopy and quantum-classical simulations. Surprisingly, the optical transition energy of PDOPT is significantly (∼2,000 cm or 0.25 eV) red-shifted relative to P3HT despite a higher static and dynamic disorder in the former. We ascribe this red shift to a side-chain induced backbone planarization in PDOPT, supported by temperature-dependent ensemble PL spectroscopy. Our atomistic simulations reveal that the bulkier 2,5-dioctylphenyl side chains of PDOPT adopt a clear secondary helical structural motif and thus protect conjugation, i.e., enforce backbone planarity, whereas, for P3HT, this is not the case. These different degrees of planarity in both thiophenes do not result in different conjugation lengths, which we found to be similar. It is rather the stronger electronic coupling between the repeating units in the more planar PDOPT which gives rise to the observed spectral red shift as well as to a reduced calculated electron-hole polarization.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Significancementioning

confidence: 99%

Direct observation of backbone planarization via side-chain alignment in single bulky-substituted polythiophenes

Raithel

Simine

Pickel

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

show abstract

“…15 The weight-average molecular weight (M w ) of the PDOPT sample was 2.8 × 10 4 g/mol with a dispersity (Đ = M w /M n ) of 1.86 (denoted as PDOPT-28). According to a previous report, the bulky side groups significantly separate the main chains of PDOPT by 1.47 nm.…”

mentioning

confidence: 99%

Anisotropic Photophysical Properties of Highly Aligned Crystalline Structures of a Bulky Substituted Poly(thiophene)

Wang¹,

Heck

Schiefer

et al. 2014

ACS Macro Lett.

Self Cite

View full text Add to dashboard Cite

The photophysical properties of a phenylsubstituted poly(thiophene), poly(3-(2,5-dioctylphenyl)-thiophene) (PDOPT), were studied as a function of polarization and degree of orientation of the crystalline structure. Under well-chosen controlled conditions, largesized spherulitic crystals of PDOPT were successfully prepared from the melt. From polarized optical microscopy and X-ray diffraction, the molecular orientation of PDOPT within the spherulite was determined, indicating that the fastest growth direction of the spherulite was the a-axis. This implied that crystallization of PDOPT was directed by the packing of the side chains rather than the backbones, which are significantly separated. As the crystalline lamellae were all radially oriented, the local absorbance strongly depended on the polarization of the incoming light. Compared to randomly oriented crystals in a quenched and thus rapidly crystallized sample, PDOPT spherulites displayed red-shifted absorption and emission spectra, combined with a reduced photoluminescence quantum yield. Even for these markedly separated polymer backbones (1.47 nm), the reduced photoluminescence suggests an enhancement of interchain interactions of highly ordered bulky substituted polythiophene induced by crystallization.T he optoelectronic properties of conjugated polymers are of importance for their application in organic electronic devices. 1 These properties are considerably determined by both the conformation of the chain-like molecules (intrachain arrangements of chromophores) and the way these molecules pack in the solid state (interchain arrangements of chromophores). In thin films of conjugated polymers prepared by standard techniques like spin coating, interchain energy transport is usually more rapid than intrachain transport. 2 Thus, the corresponding optoelectronic properties depend sensitively on the extent of interchain interactions. 3 It is widely accepted that interchain interactions in thin films are effectively influenced by chain aggregation and film morphology. Consequently, the relevant photophysical and electronic properties can be controlled by appropriate processing conditions. 4,5 Most previous studies have focused on conjugated polymers with short backbone stacking distances (<5 Å), such as in alkylsubstituted poly(thiophene)s (P3ATs) 5,6 or poly(phenylenevinylene)s (PPVs). 7,8 In these materials, interchain interactions are mainly determined by the overlap of π-orbitals, i.e., π−π interactions. To control interchain interactions, conjugated polymers with bulky side chains have been developed. 9 Bulky side chains can separate the polymer backbones from each other and thus may have a profound influence on the final properties of these materials. 9,10 In particular, the separation of main chains can strongly improve the photoluminescence (PL) quantum yield (Q y ) of conjugated systems. 11 Up to now, however, only a few reports have discussed the relationships between morphology and optoelectronic properties of conjugated systems having a large main c...

show abstract

“…Sommer and co‐workers used a heteroleptic phosphine‐pyridine catalyst to polymerize thiophene with a bulky side chain (Figure , bottom middle). They hypothesized that the success of the polymerization was partially attributed to the hemilability and reduced steric hindrance of the ligand with a pyridine moiety …”

Section: Nickel Catalysts In Ctpmentioning

confidence: 99%

“…They hypothesized that the success of the polymerization was partially attributed to the hemilability and reduced sterich indrance of the ligand with ap yridine moiety. [134] The electronic properties of monodentate phosphines are similart ot heir bidentate counterparts. However, the steric properties of monodentate phosphines are more dynamic because the ligands can adopt trans geometries or can dissociate and reassociate during polymerization.…”

Section: Phosphinesmentioning

confidence: 99%

Diversifying Cross‐Coupling Strategies, Catalysts and Monomers for the Controlled Synthesis of Conjugated Polymers

Baker

Tsai

Noonan

2018

Chemistry A European J

View full text Add to dashboard Cite

Chain-growth polymerization of aromatic building blocks (termed catalyst-transfer polycondensation or CTP) has emerged as a powerful method for the controlled synthesis of conjugated polymers. CTP affords semiconducting materials with predictable molecular weights, relatively narrow molar mass distributions and tailored backbone compositions (e.g. blocks, gradients, stars). Homogeneous catalysis utilizing transition metals has played a critical role in the rise of this field and this Minireview is designed to highlight some of the catalysts employed for these polycondensations. Some descriptions of the metal and ancillary ligands are included, along with which catalysts have been used for different aromatic monomers. Cross-coupling strategies are discussed briefly for ease of use. Finally, some potential future directions are described for further evolution of this exciting area.

show abstract

Nickel Catalyst with a Hybrid P, N Ligand for Kumada Catalyst Transfer Polycondensation of Sterically Hindered Thiophenes

Cited by 24 publications

References 29 publications

Direct observation of backbone planarization via side-chain alignment in single bulky-substituted polythiophenes

Direct observation of backbone planarization via side-chain alignment in single bulky-substituted polythiophenes

Anisotropic Photophysical Properties of Highly Aligned Crystalline Structures of a Bulky Substituted Poly(thiophene)

Diversifying Cross‐Coupling Strategies, Catalysts and Monomers for the Controlled Synthesis of Conjugated Polymers

Contact Info

Product

Resources

About