Synthesis of aromatic polyethers by scholl reaction. VIII. On the polymerizability of 1,5‐bis(phenoxy)pentanes and 1,5‐bis(phenylthio)pentane

Abstract

SYNOPSISThe synthesis and the oxidative polymerization of 1,5-bis (phenoxy )pentane, 1,5bis (phenoxy )pentane substituted with various electron-donating groups, and 1,5bis (pheny1thio)pentane is described. The polymers derived from methyl substituted 1,5bis (phenoxy )pentane monomers contain diphenyl methane, 1,2-diphenylethane, and benzyl chloride structural units. The mechanism for the generation of these structural units is presented. It consists of the proton transfer reactions from the cation-radical propagating species and subsequent reactions of the resulting benzyl radicals. The polymerizability of monomers with 1,5-pentanedioxy group is lower than that of the monomers with diphenyl sulfone group. This dissimilarity was attributed to the difference between both the reactivity and the concentration of the cation-radical propagating species resulted from these two classes of monomers. Keywords: Scholl reaction cation-radical polymerization 1,5-bis (phen0xy)pentanes polymerization mechanism polymerizability of monomers proton transfer reactions * Part VII: V. Percec, J. H. Wang, and S. Okita, J. Polym. A: Polym. Chem., 29, 1789 (1991). + 1 2 RO OR 23 23 -2n' 23 -RO OR 22 Scheme 4. nism. Sci. PartThe cation-radical polymerization mecha-

Evaluating the Effectiveness of Tethered Bis(urazolyl) Diradicals as Molecular Building Blocks for Dynamic Covalent Chemistry

“…The solid was taken up in 10 mL of acetone, and methanol was added until the solution became slightly cloudy (∼35 mL). Cooling in a freezer afforded white needles that were isolated via filtration and rinsed with cold methanol to afford 0.91 g (71%yield) of diether 7c , mp 51–52 °C (lit . 48–49 °C): 1 H NMR (400 MHz, CDCl 3 ) δ 6.58 (s, 2H), 6.53 (s, 4H), 3.95 (t, J = 6.5 Hz, 4H), 2.28 (s, 12H), 1.83 (p, J = 6.3 Hz, 4H), 1.63 (m, 2H); 13 C­{ 1 H} NMR (100 MHz, CDCl 3 )­δ 159.2, 139.3, 122.5, 112.4, 67.7, 29.2, 22.9, 21.6.…”

“…To a stirring solution of the above mixture of compounds in 20 mL of CH 2 Cl 2 was added 0.25 g (2.21 mmol) of MeTAD, followed by 170 μL (2.21 mmol) of CF 3 CO 2 H. The red color of the MeTAD decolorized within 5 h. The reaction mixture was concentrated, and the resulting solid subjected to column chromatography (5% CH 3 OH in EtOAc) to afford 0.44 g (41% yield based on MeTAD) of bis(urazole) 8a as a pale gray solid, mp 255−256 °C: 1 H NMR (400 MHz, DMSO-d 6 ) δ 10.87 (s, 2H), 6.80 (s, 4H), 4.32 (s, 4H), 2.99 (s, 6H), 2.12 (s, 12H); 13 Oxidation of Bisurazole 8a. To a mixture of 50 mg (0.10 mmol) of bis(urazole) 8a in 2 mL of CHCl 3 was added 100 mg (0.7 mmol) of Na 2 SO 4 and 120 mg (0.44 mmol) of Ni 2 O 3 (30% activity) with stirring.…”

“…The filtrate was concentrated to 43 mg of a white solid. Column chromatography (100% EtOAc) afforded 31 mg (63% yield) of dimer 4a 2 as a white solid: 1 H NMR (400 MHz, CDCl 3 ) δ 6.55 (d, J = 2.5 Hz, 4H), 6.20 (d, J = 2.5 Hz, 4H), 4.31(d, J = 7.8 Hz, 4H), 4.18 (d, J = 7.8 Hz, 4H), 3.27 (s, 12H), 2.31 (s, 12H), 1.71 (s, 12H); 13 Reaction of Dimer 4a 2 with PhSH. To 31 mg (3.14 × 10 −5 mol) of dimer 4a 2 in 1 mL of CDCl 3 was added 45 μL (0.11 mmol, 3.5 equiv based on diradical content) of thiophenol.…”

“…The filtrate was concentrated to 47 mg of a plastic-like film. Column chromatography (1:1 hexanes/EtOAc) afforded 11 mg (22% yield) of monomer 4d 1 as a plastic-like clear colorless film: 1 H NMR (400 MHz, CDCl 3 ) δ 6.48 (d, J = 2.5 Hz, 2H), 6.15 (d, J = 2.5 Hz, 2H), 3.98 (ddd, J = 9.2, 6.7, 4.9 Hz, 2H), 3.80 (dt, J = 8.7, 6.7 Hz, 2H), 3.25 (s, 6H), 2.27 (s, 6H), 1.94−1.73 (m, [4H]), 1.70 (s, 6H), 1.72− 1.60 (m, [2H]), 1.57−1.43 (m, 4H) (note: proton counts in [H] are the predicted number of hydrogens, the actual number being affected by the presence of small amounts of dimer in the sample); 13 Also isolated was 28 mg (56% yield) of dimer 4d 2 as a white solid: 1 H NMR (400 MHz, CDCl 3 ) [present in solution as a mixture of two conformers in an approximate 1.5:1 ratio, the signals of which were overlapping with the exception of one of the aromatic protons] δ 6.52 (m, 4H), 6.07 (d, J = 2.9 Hz, 4H) [signal for the minor conformer, 6.10 (d, J = 2.9 Hz 4H)], 3.90 (t, J = 6.4 Hz, 8H), 3.25 (s, 12H), 2.26 (s, 12H), 1.82 (m, 8H), 1.59 (s, 12H), 1.56 (m, 12H); 13 Reaction of a Mixture of Monomer 4d 1 and Dimer 4d 2 with PhSH. To 22 mg of a mixture of monomer 4d 1 and dimer 4d 2 in 0.75 mL of CDCl 3 was added 10 μL (0.13 mmol, 2.5 equiv based on diradical content) of thiophenol.…”

Single Electron Transfer in Radical Ion and Radical-Mediated Organic, Materials and Polymer Synthesis

“…The references for polymerization of each monomer are given here: M1 , M2 , M3 , M4 , M5 , M6 , M7 , M8 , M8′ , M8″ , M9 , M10 , M11 , M12 , and M13 …”