Low-molecular-mass organoboron quinoline-8-thiolate and -selenolate complexes as model compounds, and organoboron polymers incorporated their complex structures into the poly(p-phenylene-ethynylene) main chain were prepared. Tetracoordination states of boron atoms in the obtained compounds were confirmed by 11 B NMR spectroscopy, and the detailed structures of the model compounds were determined by singlecrystal X-ray diffraction analysis. The polymers were synthesized by Sonogashira-Hagihara coupling reaction of organoboron quinolate-based monomers having diiodo groups with 1,4-diethynylbenzene derivatives bearing electron-donating or -withdrawing groups in moderate yields. Their optical properties were studied by UV-vis absorption and photoluminescence spectroscopies. Increasing atomic number of the 16 Group atom adjacent to the boron atom caused emission shift to longer wavelength and decreasing of absolute quantum yields for both the model compounds and the polymers. There are no differences between the polymers with the donating π-conjugated linker and with the accepting one in the photoluminescence property, resulting from efficient energy transfer from π-conjugated main chain to Q ligand. Furthermore, the obtained polymers showed high refractive indices (n d > 1.66).

A series of m-carborane-based π-conjugated polymers were successfully synthesized via Sonogashira−Hagihara polycondensation reaction. Diiodo-m-carborane monomer underwent efficient polycondensation reaction with both electron-donating and electron-accepting diyne comonomers. The wide-angle structure of m-carborane monomer allowed the preparation of polymers with high molecular weights (M n = 26 600−36 400 g mol−1) and good polymerization degrees (DP = 31−56). UV−vis absorption study in dilute CHCl3 solution revealed π-conjugation extension of a p-phenylene−ethynylene segment by introducing m-carborane moieties into the polymer backbone. Further, the lack of C−C bond in the carborane cluster leads to polymers exhibiting intense blue emission in solution state (ΦF = 0.11−0.26).

Sonogashira-Hagihara polycondensations of two bis(4-iodophenyl)carborane compounds with axially chiral diyne monomers having binaphthyl unit were carried out to obtain the corresponding chiral π-conjugated polymers having o-or m-carborane segment in the main chain. The polymer structures and their optical properties were characterized by 1 H, 13 C, and 11 B NMR, FT-IR, UV-vis absorption, photoluminescence, and circular dichroism spectroscopies. Photoluminescence study revealed that the polymer having m-carborane exhibited intense blue emission in solution state, whereas polymers having o-carborane exhibited aggregation-induced emission (AIE). All polymers showed strong CD signals, indicating the construction of highly ordered conformation.

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Ruthenium-catalyzed annulation of 1-naphthylsilanes with internal alkynes afforded silaphenalenes through cleavage of the C-H bond at the 8-position of the naphthalene. [RuH2 (CO){P(p-FC6 H4 )3 }3 ] efficiently catalyzed the reaction. The use of 1-naphthyldiphenylsilane as a substrate resulted in a better yield of the annulation product compared to the use of silanes with alkyl groups on the silicon atom. Internal alkynes with both aryl and alkyl groups were tolerated in this reaction.

Rhodium-catalyzed copolymerization between 1,4-bis(acetylamino)benzene and diynes through C−H bond cleavage afforded π-conjugated polymers containing benzodipyrrole moieties. The polymers with substituted benzene units exhibited nearly the same absorption peaks and HOMO levels. Fluorenone and benzothiadiazole moieties can be also introduced as electron-acceptor units to the main chain by polymerization in tert-amyl alcohol and tetrahydropyran as mixed solvent, leading to absorption at longer wavelength.π-Conjugated polymers showed attractive absorption, luminescence, and semiconducting properties, which can be applied to organic photovoltaic cells, light-emitting diodes, or field-effect transistors. 1 To tune their power conversion of efficiency, color or mobility from the synthetic point of view, many π-conjugated polymers with various (hetero)arylene moieties in the main chains were proposed and synthesized. 2 Among them, N-hetero arenes are useful to modify the frontier orbital energies correlated to the optical and electronic properties. 3 While aromatics containing amide or imine moieties lower the LUMO levels and tend to accept electrons, pyrrole-type aromatics elevate the HOMO levels and elevate hole affinity.One of the most conventional methods to prepare soluble π-conjugated polymers is transition metal-catalyzed crosscoupling polymerization through cleavage of carbon−halogen (C−X) bond and carbon−metal bond. 4 This approach bases on successive formation of a single bond between two aromatic units. Although the cross-coupling polymerization usually achieved high molecular weight and reliable regioselectivity, preparation of the halogenated, and metalated monomers sometimes required many synthetic steps to introduce functional groups at desired positions and generate a lot of byproducts and impurities. In recent years, transition metalcatalyzed direct C−H arylations have been applied to polymerization to reduce the cost and waste. 5 In direct C−H arylation polymerization through C−H and C−X cleavage, monomers with acidic protons or directing groups gave soluble π-conjugated polymers in good yield and regioselectivity. Moreover, some results supported that purity or performance of polymers by C−H direct arylation was better than those by conventional cross-coupling method. 6 Nowadays, transition metal-catalyzed C−H activation followed by alkyne insertion is useful method for synthesis of fused aromatic rings. 7 Fagnou and co-workers developed facile synthesis of indoles by rhodium-catalyzed C−H bond cleavage of acetanilide and alkyne insertion. 8 The reaction proceeded under mild condition and gave indoles in good yield and high regioselectivity. Herein, we applied the C−H functionalization leading to indoles to synthesis of π-conjugated polymers containing N-heteroarenes in the main chain. The synthetic efficiency of the polymerization described here is highlighted by simultaneous formation of N-heterocycles with extension of the main chain and also by no need to prepare halogenated monomers or organometa...