Bismaleimides bearing electron-donating chromophore moieties, A (=)-D (*)-A (=) type monomers, i.e. N,N-bis(4-maleimidophenyl)methylamine (BMIPMA), N,N-bis(4-maleimidophenyl)aniline(BMIPA) and 2,5-bis(4-maleimido phenyl)-1,3,4-oxadiazole(BMIPODA) as well as their corresponding saturated model compounds, i.e. N,N-bis(4-succinimidophenyl)methylamine( BSIPMA), N,N-bis(4-succinimidophenyl)aniline(BSIPA) and 2,5-bis(4-succimidophenyl)-1,3,4-oxadiazole (BSIPODA) were synthesized. It was found that the fluorescence quantum yields of A (=)-D (*)-A (=) monomers were always dramatically lower than those of their corresponding saturated model compounds. These A (=)-D (*)-A (=) bismaleimides possess a strong SSQE, which is attributed to an intramolecular charge transfer interaction.
A β-diketone-bridged chromophore-containing acrylic monomer, 1-(4-dimethylaminophenyl)-4-methyl-4-pentene-1,3-diketone(DMPDK) and its saturated model compound, 1-(4-dimethyl aminophenyl)-1,3-butanedione(DMBDK) were synthesized and investigated by spectroscopy. It was found that the fluorescence intensity of DMPDK was much lower than that of DMBDK at the same concentration, which indicates that DMPDK, a β-diketone-bridged acrylic monomer having chromophore moiety, also showed fluorescence structural self-quenching effect(SSQE). Photo-induced tautomerization of DMBDK in acetonitrile was studied by means of UV and fluorescence spectroscopy. The results imply that the fluorescence method is capable of monitoring tautomerization of some fluorescent β-diketones.
To avoid the damage to catalytic system in ATRP by the carboxyl groups in vinyl benzoic acid, a well defined poly( p vinyl benzoic acid) was synthesized via ATRP in the tertiary butyl ester form. The ATRP of t butyl p vinyl benzoate ( t BVB) was studied kinetically. The results showed that t BVB can be polymerized in a controlled way by ATRP. It was found that the polymerization rate of t BVB is much faster than that of St, meaning that the electron withdrawing ester group affects the polymerization obviously. Well defined diblock copolymers of St and t BVB were prepared by using bromo terminated PBVBs as macroinitiators via ATRP. After removal of the t butyl group by hydrolysis, well defined amphiphilic diblock copolymers of styrene and p vinyl benzoic acid (PSt b PBVA) were obtained.
Bismaleimides bearing electron\|donating chromophore moieties, i.e.N,N \|bis(4\|maleimidophenyl)\|methylamine (BMIPMA),and its saturated model compound N,N\| bis(4\|succinimidophenyl)\|methylamine(BSIPMA) were synthesized and their absorption and fluorescence behaviors were investigated. It was found that BMIPMA possess a strong fluorescence structural self\|quenching effect (SSQE).There is almost no fluorescence emission observed for BMIPMA,whereas its saturated model compound BSIPMA displays a strong fluorescence emission at the same chromophore concentration.On the basis of the SSQE,a new fluorescence approach was developed to monitor the process of the copolymerization of bismaleimides with diamines,which can directly reflect the consumption of the CC bond of maleimide unit.The results agreed well with that obtained by 1H\|NMR measurement pused.
