Tadatomi Nishikubo

Synthesis and photochemical reaction of novel p‐alkylcalix[n]arene derivatives containing cationically polymerizable groups

New photoreactive p-methylcalix[6]arene (MCA) derivatives containing cationically polymerizable groups such as propargyl ether (calixarene 1), allyl ether (calixarene 2), and ethoxy vinyl ether (calixarene 3) groups were synthesized with 80, 74, and 84% yields by the substitution reaction of MCA with propargyl bromide, allyl bromide, and 2-chloroethyl vinyl ether (CEVE), respectively, in the presence of either potassium hydroxide or sodium hydride by using tetrabutylammonium bromide (TBAB) as a phase transfer catalyst (PTC). The p-tert-butylcalix[8]arene (BCA) derivative containing ethoxy vinyl ether groups (calixarene 4) was also synthesized in 83% yield by the substitution reaction of BCA with CEVE by using sodium hydride as a base and TBAB as a PTC. The MCA derivative containing 1-propenyl ether groups (calixarene 5) was synthesized in 80% yield by the isomerization of calixarene 2, which contained allyl ether groups, by using potassium tert-buthoxide as a catalyst. The photochemical reactions of carixarene 1, 3, 4, 5, and 6 were examined with certain photoacid generators in the film state. In this reaction system, calixarene 3 containing ethoxy vinyl ether groups showed the highest photochemical reactivity when bis-[4-(diphenylsulfonio)phenyl]sulfide bis(hexafluorophosphate) (DPSP) was used as the catalyst. On the other hand, calixarene 1 containing propargyl ether groups had the highest photochemical reactivity when 4-morpholino-2,5-dibuthoxybenzenediazonium hexafluorophosphate (MDBZ) was used as the catalyst. It was also found that the prepared carixarene derivatives containing cationically polymerizable groups such as propargyl, allyl, vinyl, and also 1-propenyl ethers have good thermal stability.

Large photoinduced refractive index changes of a polymer containing photochromic norbornadiene groups

We prepared a polymer containing pendant norbornadiene (NBD) moieties, P(MMA0.43-co-GMA0.57-PNCA), and measured absorbance and refractive index spectra before and after photoisomerization of norbornadiene moieties. Large photoinduced refractive index changes of ∼0.01 were obtained at 632.8 nm, the region far from the absorption band. A quantum yield of 0.50 was obtained for the photoisomerization of NBD moieties in this polymer. These values are sufficient to make efficient channel waveguides by photoisomerization.

Convenient syntheses of cyclic carbonates by new reaction of oxiranes with β-butyrolactone

Abstract Cyclic carbonates were synthesized by reactions of the corresponding oxiranes with β-butyrolactone using quaternary salts such as tetrabutylammonium bromide or 18-crown-6 = KBr as a catalyst.

A novel noria (water-wheel-like cyclic oligomer) derivative as a chemically amplified electron-beam resist material

A novel ladder-type cyclic oligomer (molecular water-wheel = noria) derivative containing t-butyl ester groups was synthesized. This derivative (noria-COOtBu) had good thermal stability, good solubility in common organic solvents, and good film-forming ability. The photo-induced deprotection (UV irradiation for 30 min followed by heating at 130 °C) of films of noria-COOtBu was examined in the presence of a photo-acid generator, and it was found that deprotection of the t-butyl groups proceeded smoothly to give the corresponding carboxylic acid derivative (noria-COOH). Furthermore, when noria-COOtBu(71) (ratio of t-butyl ester groups: 71%) was examined as an electron-beam resist material, a clear line and space pattern was obtained at a resolution of 70 nm.

A novel synthesis of polyesters with pendant hydroxyl groups by polyaddition of bis(oxetane) with dicarboxylic acids catalyzed by quaternary onium salts

Abstract Polyesters with pendant primary hydroxyl groups were synthesized by polyadditions of bis(oxetane) with dicarboxylic acids. The polyaddition of bis(3-methyl-3-oxetanylmethyl) terephthalate (BOMT) with adipic acid was carried out in hexamethylphosphorictriamide (HMPA) using certain quaternary onium salts as catalysts at 140°C for 12 h to produce the corresponding polyester, and tetraphenylphosphonium bromide (TPPB) showed the highest catalytic activity among quaternary onium salts used. However, the reaction did not occur without the catalyst or with triethylamine under the same conditions. The yield and the molecular weight of soluble polymer increased with increasing reaction temperature, reaction time, catalyst concentration, and monomer concentration. However, insoluble gel products were obtained when the reaction was performed under less than strict reaction conditions. Polyadditions of BOMT with sebacic acid, isophthalic acid, terephthalic acid, and 2,2′-bis(4-carboxylphenyl)hexafluoropropane were also carried out under similar reaction conditions, and corresponding polyesters with pendant primary hydroxyl groups were obtained in good yields.

Synthesis of polymers in aqueous solutions: Esterification reaction of poly(methacrylic acid) with alkyl halides using DBU in aqueous solutions

A convenient esterification reaction of poly(methacrylic acid) (PMAA) with certain alkyl halides was performed using 1,8-diazabicyclo-[5.4.0]-7-undecene (DBU) as a base in aqueous solution or in water. The esterification reaction of PMAA with propargyl bromide (PB) proceeded very smoothly and quantitatively at 30°C to give corresponding poly(propargyl methacrylate), although the rate of the reaction decreased with increasing water. The reaction of PMAA with benzyl bromide, o-nitrobenzyl bromide, and p-nitrobenzyl bromide gave corresponding poly(methacrylic ester) using DBU under suitable reaction conditions in water. The esterification reactions of PMAA with PB were carried out using certain organic bases such as triethylamine, 4(N,N-dimethylamino)pyridine and pyridine. Inorganic bases such as sodium carbonate, sodium hydroxide, potassium carbonate, and potassium hydroxide were also tried under the same conditions as with DBU. However, the degrees of estrification with all these bases was much lower than that with DBU.

Novel extreme ultraviolet (EUV)-resist material based on noria (water wheel-like cyclic oligomer)

The synthesis and properties of noria derivatives (noria-ADs) with pendant adamantate (AD) groups were examined to assess the suitability of these compounds for application as extreme ultraviolet (EUV)-resist materials. Noria-ADs with various degrees of introduction (DI) of AD were synthesized by adjusting the reactant feed ratio and reaction temperature. The differences in their physical properties (solubility, thermal stability, and film-forming ability) were consistent with the differences in DI values. The patterning properties of noria-AD23 (DI = 23) and noria-AD44 (DI = 44) were investigated in an EUV-resist system, and noria-AD23 yielded higher resolution than noria-AD44, providing a clear line and space pattern with a resolution of 26 nm and a line-edge roughness (LER) of 8.3 nm.

Novel synthesis of polyphosphonates by the polyaddition of bis(epoxide) with diaryl phosphonates

The polyaddition of bisphenol A diglycidyl ether (BPGE) with bis(4-chlorophenyl) phenylphosphonate was carried out using quaternary onium salts or crown ether complexes as catalysts. When the polyaddition was performed using tetrabutylammonium chloride, tetrabutylphosphonium chloride, or 18-crown-6/KCl in N- methyl-2-pyrrolidone at 110°C for 48 h, the corresponding polyphosphonate with moderated molecular weights was obtained in 88–96% yields. The structure of the resulting polyphosphonate was confirmed by IR and 1H-NMR spectra. The polyaddition of BPGE with various diaryl phosphonates also proceeded very smoothly to produce the corresponding polyphosphonates with moderate molecular weights.

Thermal analysis of epoxy curing using polyfunctional active esters as curing agents

Abstract The curing behavior of bisphenol A diglycidyl ether (BADGE) has been studied by differential scanning calorimetry and IR spectroscopy using active esters, the trifunctional compound 1,3,5-triacetoxybenzene (TAB) and tetrafunctional tetraphenoxycarbonyl pentaerythritol (TPCP) as curing agents, with which no free hydroxyl groups are left in the cured resins. The effects of the ratio of ester groups to epoxide groups ( r ) in the reaction mixture on the glass transition temperature ( T g ) and the thermal stability of the cured resins were also examined by thermomechanical analysis and thermogravimetry respectively. The T g has the maximum value of 72°C at r = 1 for either TAB or TPCP as curing agent. The thermal stability increases with increasing value of r .

A novel polyaddition of bis(epoxide)s with triazine diaryl ether for the synthesis of poly(ether)s containing triazine group in the main chain

Poly(ether)s (P-1–P-4) containing triazine groups in the main chain and pendant phenoxy groups in the side chain were synthesized by the polyaddition of bis(epoxide)s with 2,4-di-(p-chlorophenoxy)-6-(diphenylamino)-s-triazine (DCTA) with quaternary onium salts or crown ether complexes as catalysts. The polyaddition of diglycidyl ether of bisphenol A with DCTA proceeded smoothly in chlorobenzene at 120 °C for 24 h to give P-1 with a number-average molecular weight of 24,800 in a 95% yield when tetraphenylphosphonium chloride (TPPC) was used as a catalyst; however, no reaction occurred without a catalyst under the same reaction conditions. Polyadditions of other bis(epoxide)s with DCTA also proceeded smoothly with 5 mol % TPPC as a catalyst in chlorobenzene to produce the corresponding polymers (P-2–P-4) in high yields under similar reaction conditions.