ABSTRACT

ABSTRACT

Abstract

Abstract

Abstract

An effective method to stabilize oligocarbynes as a modelfor polycarbyne by the simultaneous complexation withα-cyclodextrin (α-CD) is described. 1,12-Bis(9-phenanthryl)-1,3,5,7,9,11-dodecahexayne possessing one or two α-CD molecules was prepared by the oxidative coupling reaction of the corresponding triyne in the presence of α-CD. The resulting rotaxanes proved to be stable enough in comparison with the corresponding free oligoynes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

A novel synthetic method for soluble precursor polymers of poly(p-phenylene vinylene) (PPV) derivatives by the palladium-catalyzed three-component coupling polycondensation of aromatic diiodides, aromatic bis(boronic acid) derivatives, and norbornadiene is described. For example, the polymerization of 1,4-diiodo-2,5-dioctyloxybenzene, benzene-1,4-bis(boronic acid propanediol ester), and norbornadiene at 100 °C for 3 days provided a polymer consisting of the three monomer units in a 97% yield (number-average molecular weight = 3100, weight-average molecular weight/number-average molecular weight = 1.37). A derivative of PPV was produced smoothly by the retro Diels–Alder reaction of the polymer both in a dodecyloxybenzene solution and in a film at 200 °C in vacuo. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3403–3410, 2005

Organometallic polymers containing metallacycles in the main chain were prepared by the reactions of diynes with low-valent organometallic complexes such as CpCo(PPh₃)₂, CP₂Ti(CH₂=CHC₂H₅), and (ⁱPrO)₂Ti(CH₂=CHCH₃). Their polymer reactions involving the conversion of the main chain structures gave rise to polymers containing functional groups in their main chain repeating units. Design and synthesis of organometallic polymers that potentially serve as novel functional materials are also described.

The anionic polymerization behavior of 2-methyl-4-phenyl-1-buten-3-yne (2) was investigated to get information on the effect of substituent at the 2-position. The polymerization of 2 did not proceed in tetrahydrofuran at –78°C by lithium initiators, while sodium initiators can conduct the polymerization smoothly to give polymers consisting of a specific 1,2-polymerized unit. The living nature of the polymerization of 2 by diphenylmethylsodium was supported by the post-polymerization experiment.

The coordination polymerization of 1-ethynylcyclohexene was carried out using various rhodium catalysts. Polymerization catalyzed with [Rh(norbornadiene)Cl]₂/triethylamine gave a well-defined polyacetylene derivative bearing conjugated double bond moieties, whose UV-vis absorption spectrum has its maximum at 380 nm and cut off at 500 nm.

An end-π-allylnickel macroinitiator (3) was prepared by the reaction of poly(ethylene glycol) allenyl methyl ether with an excess amount (5 equiv) of [(π-allyl)NiOCOCF₃]₂ (1) in the presence of PPh₃ ([PPh₃]/[1] = 1). The resulting macroinitiator was used as an initiator for the polymerization of 1-phenylethyl isonitrile (4a) to give a block copolymer [poly(ethylene glycol)-block-poly(4a)]. The molecular weight and composition of the block copolymers were controlled by the molecular weight of 3 and the ratio of 4a to 3. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 495–499, 2001

Sulfonium-containing polymers prepared from dibenzothiophene and diphenyl sulfide were applied as both alkylating agents and latent initiators for the cationic polymerization of glycidyl phenyl ether. The alkylation of acetonitrile proceeded smoothly with poly(S-n-octyl-2-vinyldibenzothiophenium tetrafluoroborate) (4; 64 mol % octyldibenzothiophenium tetrafluoroborate unit) to give N-(n-octyl)acetamide in an excellent yield on the basis of the starting octyldibenzothiophenium tetrafluoroborate unit in 4. The cationic polymerization of glycidyl phenyl ether was also carried out in the presence of poly(S-methyl-2-vinyldibenzothiophenium tetrafluoroborate) or poly(S-n-octyl-4-vinyldiphenylsulfonium tetrafluoroborate) to confirm their moderate thermal latent activity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3928–3933, 2001

The curing behavior of bisphenol-A-type epoxide oligomers (Ep) was evaluated by differential scanning calorimetry in the presence of S-alkylsulfonium salts of dibenzothiophene, phenoxathiin, thianthrene, thioanisole, and tetrahydrothiophene as thermal latent initiators. These initiators dissolved homogeneously in Ep, except for 2,8-dimethoxy-5-methyldibenzothiophenium tetrafluoroborate, and the curing reaction of the resulting mixtures occurred on heating, except for S-methyltetrahydrothiophenium tetrafluoroborate. The initiation activity of these salts was controlled by the character of the substituents on the benzene ring, the leaving sulfide group, and the S-alkyl group. Presumably, the electron density on the sulfide moieties and the stability of the carbocation released from the sulfonium salts affected the initiating temperature. A good correlation was obtained between the initiating temperature and the electron density of the sulfur atom of the corresponding sulfides, estimated from ab initio molecular orbital calculations in which the initiating temperature became higher as the electron density of the sulfur atom increased. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 868–871, 2001

The anionic polymerization of derivatives of 4-phenyl-1-buten-3-yne was carried out to investigate the effect of substituents on the polymerization behavior. The polymerization of 4-(4-fluorophenyl)-1-buten-3-yne and 4-(2-fluorophenyl)-1-buten-3-yne in tetrahydrofuran at −78 °C with n-BuLi/sparteine as an initiator gave polymers consisting of 1,2- and 1,4-polymerized units in quantitative yields with ratios of 80/20 and 88/12, respectively. The molecular weights of the polymers were controlled by the ratio of the monomers to n-BuLi, and the distribution was relatively narrow (weight-average molecular weight/number-average molecular weight < 1.2), supporting the living nature of the polymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1016–1023, 2001