Synthesis of Conjugated Polymers via Organomagnesium and Organometallic Coupling

Magnesium, turnings (Tokyo Chemical Industry Co., Ltd., Tokyo, Japan); 1,2-dibromoetane (>99.0%, Tokyo Chemical Industry Co., Ltd.); 2-bromo-3-hexylthiophene (>97.0%, Tokyo Chemical Industry Co., Ltd.); [1,3-bis(diphenylphosphino)propane]dichloronickel(II) (Ni(dppp)Cl₂) (Sigma-Aldrich, St. Louis, MO, USA); 2-bromo-3-hexyl-5-iodothiophene (>97.0%, Tokyo Chemical Industry Co., Ltd.); isopropylmagnesium chloride–lithium chloride (i-PrMgCl·LiCl) (15% in tetrahydrofuran (THF), ca. 1 mol L⁻¹, Tokyo Chemical Industry Co., Ltd.); boronic acid-functionalized resin (boronic acid, polymer-bound, 200–400 mesh, extent of labeling: 1.4–2.2 mmol/g loading, 1% cross-linked with divinylbenzene, Sigma-Aldrich); potassium carbonate (>80%, Wako Pure Chemical Industries, Ltd.) tetrakis(triphenylphosphine)palladium(0) (Pd(PPh₃)₄) (97.0%, Tokyo Chemical Industry Co., Ltd.); N,N,N’,N’-tetramethylethylenediamine (TMEDA) (>98.0%, Tokyo Chemical Industry Co., Ltd.); sec-butyllithium (sec-BuLi) (in cyclohexane, n-hexane, ca. 1 mol L⁻¹, Kanto Chemical Co., Inc.); trimethyltin chloride (Me₃SnCl) (>98.0%, Tokyo Chemical Industry Co., Ltd.); bis(benzonitrile)palladium(II) chloride (PdCl₂(PhCN)₂) (>95%, Sigma-Aldrich); triphenyl phosphine (PPh₃) (>97.0%, Wako Pure Chemical Industries, Ltd.); chloroacetone (>95.0%, stabilized with magnesium oxide, Tokyo Chemical Industry Co., Ltd.); phosphoryl chloride (POCl₃) (99.0%, Tokyo Chemical Industry Co., Ltd.); aminomethyl-functionalized resin (aminomethyl polystyrene resin cross-linked with 1% DVB (200–400 mesh) (2.0–3.0 mmol g⁻¹)), 1,4-diazabicyclo[2.2.2]octane (DABCO) (>98.0%, Tokyo Chemical Industry Co., Ltd.); silver hexafluoroantimonate(V) (AgSbF₆) (>97.0%, Tokyo Chemical Industry Co., Ltd.); 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) (98%, Angene Chemical, Nanjing, China); THF super dehydrated, stabilizer free (99.5%, Wako Pure Chemical Industries, Ltd., Osaka, Japan); n-hexane (>99.5%, Kanto Chemical Co. Ltd., Tokyo, Japan); acetone (>99.5%, Kanto Chemical Co. Ltd.); chloroform (CHCl₃) (>99.0%, Kanto Chemical Co. Ltd.); methanol (MeOH) (>99.6%, Junsei Chemical Co. Ltd.); dichloromethane (CH₂Cl₂), specially prepared reagent for fluorometry (≥99.5%, NACALAI TESQUE, Co., Ltd., Kyoto, Japan); CDCl₃ (99.8 atom%D, contains 0.5 wt.% silver foil as stabilizer, 0.03% (v/v) TMS, Sigma-Aldrich); dichloromethane-d₂ (99.9 atom%D, Tokyo Chemical Industry Co., Ltd.) were used as received without purification. THF for cyclization (stabilizer free, water content <10 ppm, Kanto Chemical Co. Ltd.) and N,N-dimethylformamide (DMF), super dehydrated (99.5%, Kanto Chemical Co. Ltd.) were purified by a solvent purification system (MBRAUN MB-SPS-Compact). Toluene (>98.0%, Kanto Chemical Co. Ltd.) was distilled over Na. The polymerization experiments were carried out in an MBRAUN stainless steel glovebox equipped with a gas purification system (molecular sieves and copper catalyst) in a dry argon atmosphere (H₂O, O₂ <1 ppm). The moisture and oxygen contents in the glovebox were monitored by an MB-MO-SE 1 moisture sensor and an MB-OX-SE 1 oxygen sensor, respectively.