Unique steric and geometry induced stoichiometries observed in the divergent synthesis of poly(ester-acrylate/amine) (PEA) dendrimers
作者:Douglas R. Swanson、Baohua Huang、Hosam G. Abdelhady、Donald A. Tomalia
DOI:10.1039/b700193m
日期:——
controlled dendrimers possessing, macrocyclic (looped) structures (i.e., geometrically induced stoichiometry (GIS)) were formed when adequate reactivity space was available on the amine scaffolding. However, when amine core reaction sites became highly congested, one observed the formation of well defined, non-ideal dendrimers exhibiting sterically induced stoichiometries (SIS). It is postulated that
这项工作描述了未保护的,支链的(A)x型丙烯酸酯单体(即,三羟甲基丙烷三丙烯酸酯(TMPTA);x = 3或季戊四醇四丙烯酸酯(PTA);X = 4),以温和的条件下的各种单和多亚烷基胺内核,以产生(芯:胺); G = 1;[树状-聚(酯-丙烯酸酯)z ];(PEA)型树状聚合物的一步。十分明显的是,这种策略并不需要像传统的Tomalia型聚(酰氨基胺)(PAMAM)树状大分子合成所需要的那样,需要大量过量的试剂方案,而产生的寡聚/聚合物副产物却相对较少。以高收率获得了理想的,数学上可预测的树枝状大分子结构,仅适度过量(即,4.0摩尔的单体/核心-NH);而在较低的比率(即0.5 / 2.0摩尔的单体/核心-NH)下,具有几何结构的非理想树枝状大分子具有大环(环状)结构(即当胺骨架上有足够的反应空间时,就形成了几何诱导化学计量(GIS)。但是,当胺核心反应位变得高度拥挤时,人们观察到形