Polyhydroamination Of Alkynes

Alkynes have rich chemical properties,and the resulting polymers from alkynes often have conjugated structures,which will endow polymeric materials with potential optoelectronic properties.Therefore,it is very significant to develop efficient alkyne-based polymerizations for preparing functional polymeric materials.Hydroamination of alkynes is a simple and efficient method to directly synthesize C-N bond-containing compounds.Over the past few decades,the hydroamination of alkynes has been widely studied,but it has not been developed into a powerful tool for the polymer synthesis.In other words,the direct polyhydroamination of alkynes has not been reported yet.In this thesis,we focus on the development of polyhydroamination of alkynes,and using them to prepare functional nitrogen-containing polymers.The detailed contents are described as follows.Firstly,we designed and synthesized a bifunctional activated electrophilic amine,and optimized its polymerization conditions with internal alkynes under Cu(II)catalyst.After optimization,a novel Cu(II)-catalyzed polyhydroamination of internal alkynes with electrophilic amine was successfully established.This polymerization proceeded smoothly in the presence of Cu(OAc)2 under mild conditions,producing polyenamines with high molecular weight(M_w up to 12650)in high yields(up to 95%).The polymerization can undergo through an electrophilic amination,and the regioselectivity of this polymerization can be tuned by adjusting the electronegativity of the two acetylenic carbon atoms of the monomer.Moreover,by introducing the aggregation-induced emission(AIE)active tetraphenylethylene(TPE)moiety into polymer backbones,the resulting polymer also has AIE feature,and can be used for highly sensitive detection of explosive.Secondly,based on the activated internal alkynes,we have successfully developed a simple and efficient Cu(I)-catalyzed amino-yne click polymerization.This click polymerization was carried out under solvent-free conditions.After reaction at 140 oC for 2 h,polyenamines with high molecular weights(M_w up to 13470)were obtained in high yields.Moreover,this click polymerization proceeded in a regio-specific and stereo-selective fashion,and sole Markovnikov additive polymers with the fraction of Z-isomeric units up to 94% were obtained.The resultant polymers possess excellent solubility,high thermal stability,and strong UV-light shielding efficiency,and good visible light transparency.Thirdly,changed the activated internal alkynes to activated terminal alkynes,a spontaneous amino-yne click polymerization was also successfully established.This click polymerization could proceed at room temperature without any external catalyst,and poly(?-aminoacrylate)s with high molecular weights(M_w up to 64400)were obtained quantitatively.More importantly,the click polymerization can proceed in regio-and stereo-specific fashion,and sole anti-Markovnikov additive products and 100% E-isomer were obtained.Density functional theory(DFT)calculation was used to unveile the underneath reaction mechanism of this amino-yne click polymerization.In addition,we also explored the application of the resulting AIE-active polymeric material in the explosives detection and bioimaging.It was found that the limits of detection of TPE-containing polymers were 3.87 × 10-6 and 1.28 × 10-7 M,respectively.The low molecular weights P-TPE possesses low cytotoxicity and excellent photostability,and can specifically label lysosomes.Finally,using the spontaneous amino-yne click polymerization,series of hyperbranched poly(?-aminoacrylate)s were synthesized.The resulting hyperbranched polymers have good solubility and thermal stability.Moreover,by introducing the TPE moiety into polymer backbones,the AIE-active hyperbranched poly(?-aminoacrylate)s were obtained,and its nano-aggregates can be used for the sensitive detection of explosives.The special three-dimensional topologies of hyperbranched polymers can effectively improve their detection sensitivity.