LINEAR AND HYPERBRANCHED POLYMERS WITH HIGH THERMAL STABILITY AND LUMINESCENCE EFFICIENCY

New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-phenyl-1-hexyne (1), 2,5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl (6) were synthesized. Homopolymerization of 1 and copolycyclotrimerizations of 3 and 6 with 1-heptyne and 1-octyne have been achieved with WCl6- and TaCl5-Ph4Sn catalysts, respectively, giving soluble linear disubstituted polyacetylene (2) and hyperbranched polyarylenes (5 and 8) with high molecular weights (up to 1.2 x 10(5)) in high yields (up to 98%). The structures and properties of the polymers are characterized and evaluated by R NMR, TGA, UV, photoluminescence (PL), and electroluminescence (EL) analyses. All the polymers possess high thermal stability and emit strong blue light upon photoexcitation. The intensity of the emitted light is greater than that of poly(1-phenyl-1-octyne), a well-known highly luminescent disubstituted polyacetylene. Little aggregation-induced red shift in the PL was observed in the thin films of the polymers. By constructing a multi-layer EL device, high EL quantum yield (0.18%) has been achieved in 2, which are the best results for substituted polyacetylenes attainable so far.

SYNTHESIS AND PHOTOLUMINESCENCE OF AN ANTHRACENE-CONTAINING HYPERBRANCHED POLY(ARYLENEETHYNYLENE)

A hyperbranched poly（aryleneethynylene） containing anthracene chromophore was synthesized by palladiumcatalyzed cross-coupling reaction of 2,4,6-triiodophenyl 9-anthracenylcarboxylate with 9,9-bis[4-（2-propynyloxy）phenyl]- 9H-fluorene. The structure and properties of the polymer are characterized and evaluated by NMR, IR, UV, PL and TGA analyses. The polymer is soluble in common organic solvents, possesses high thermal stability （Td 〉 330℃）, and emits a strong blue light of 465 nm in both solution and solid states.

NITROXIDE-MEDIATED FREE RADICAL SYNTHESIS OF MESOGEN-JACKETED LIQUID CRYSTAL POLYMERS

The first TEMPO-mediated 'living' free radical polymerization of liquid crystalline monomer, 2, 5-bis[(4-methoxyphenyl)oxycarbonyl]styrene (MPCS), was carried out at 130 degrees C with BPO as an initiator. The molecular weight of the polymer can be varied from rather low values to high values while maintaining narrow polydispersity. It was observed that the polymerization of MPCS proceeded much faster than that of styrene. A tentative explanation for this fast polymerization was suggested.

Catalyst-Free Four-Component Spiropolymerization for the Construction of Spirocopolymers with Tunable Photophysical Properties

Spiropolymers have gained a great deal of interest from both academic and industrial fields by virtue of their unique geometric structures and physical properties.Herein,we prepared a series of spirocopolymers through the catalyst-free four-component spiropolymerization of diisocyanides,activated alkynes,and two different kinds of monomers with reactive carbonyl groups.It is found that the polymerization reactivity of monomers,feeding modes,and feed ratios play significant roles in spirocopolymerization.Monomers with high reactivity and feeding reactive monomers first contribute to improving the molecular weights and yields of the polymers.The constructed copolymers have two different kinds of spiro structures,which is confirmed by the nuclear magnetic resonance.In addition,the spirocopolymers display the unique cluster-triggered emission and aggregation-induced emission properties,and their emission properties can be well-modulated by altering the ratio of comonomers.It is highly anticipated that this line of research will enrich the methodology of multi-component spiropolymerization,and provide a new insight into developing spiropolymers with various spiro structures and tunable properties.

A pillar[5]arene-based side-chain pseudorotaxanes and polypseudorotaxanes as novel fluorescent sensors for the selective detection of halogen ions

A pseudorotaxane and its polypseudorotaxanes formed between pillar[5]arene moieties and noctylpyrazinium cations as novel fluorescent sensors for the selective detection of halogen ions were reported.A collapse of these pillar[5]arene-based pseudorotaxanes and polypseudorotaxanes occurred upon the addition of Cl,Br,and I（tetrabutylammonium salts）,respectively,leading to their fluorescence recovery.The fluorescence enhancement of the pseudorotaxane and the polypseudorotaxanes increases in the order of I

Synthesis and Properties of Photodegradable Poly(furan-amine)s by a Catalyst-free Multicomponent Cyclopolymerization

A series of new photodegradable poly(furan-amine)s(PFAs) were synthesized by a one-pot, catalyst-free, multicomponent cyclopolymerization between diisocyanides, dialkylacetylene dicarboxylates, and aromatic dialdehydes. All polymerizations were conducted in toluene at 100 ℃ for 6 h without inert gas protection and furnished polymers with a satisfactory molecular weight(Mw up to32200) and yield. The PFA structure was confirmed by spectroscopic techniques, such as GPC, FTIR, and NMR, as well as by comparison with a model compound. The polymers exhibited good solubility in common organic solvents and thermal stability. All the PFAs had high refractive indices in the visible light region(400 nm to 800 nm). Moreover, the PFAs were substantially degraded by UV irradiation due to the presence of furan rings. The film thickness reduction rate could be over 90%.