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以己二胺为分子内核,室内合成了一类支化代数为1.0G的聚酰胺-胺型树枝状分子己二胺四丙酰胺二胺(1.0G支化物)。应用ESI-MS技术研究并表征了该支化物的分子结构与正、负离子扫描条件下的主要特征碎片离子及主要裂解途径。1.0G支化物在正、负离子模式下均可以得到较佳的质谱信息。在正离子模式下,容易与H+形成[M+H]+准分子离子,并裂解形成碎片m/z573.41,m/z 555.40,m/z 471.30,m/z 459.30,m/z 453.28,m/z 369.17,m/z357.16等。在负离子模式下丢失一个H+,形成[M-H]-准分子离子,并进一步碎裂成碎片m/z 571.43,m/z 511.29,m/z 457.20,m/z 397.05,m/z 342.99,m/z240.84等。分别阐述了1.0G支化物在正、负离子模式下的电喷雾质谱裂解规律并对主要特征碎片离子进行了结构归属,为进一步对聚酰胺-胺型树枝状分子的表征与结构指认提供了有价值的依据。
A hexamethylenediamine tetramethacrylamide diamine (1.0G branched product) was synthesized with hexamethylenediamine as its molecular core. A series of polyamide - amine dendrimers with branched algebra of 1.0G were synthesized indoors. The molecular structure of the branched product and the main characteristic fragment ions and the main lysis pathway under positive and negative ion scanning conditions were studied and characterized by ESI-MS technique. 1.0G branch in positive and negative ion mode can get better MS information. In positive mode, [M + H] + quasi-molecular ions are easily formed with H + and cleave to form fragments m / z 573.41, m / z 555.40, m / z 471.30, m / z 459.30, m / z 453.28, m / z 369.17, m / z 357.16 and the like. An H + was lost in negative ion mode to form [MH] - excimer ions and further fragment to fragment m / z 571.43, m / z 511.29, m / z 457.20, m / z 397.05, m / z 342.99, z240.84 and so on. The rule of electrospray ionization mass spectrometry of 1.0G branch products in positive and negative ion mode was described respectively, and the main characteristic fragment ions were assigned to the structure, which provided valuable information for further characterization and structure identification of polyamide - amine dendrimer The basis.