论文部分内容阅读
采用手性冠醚(+)-2,3,11,12-四羧基-18-冠-6(简写为18-C-6-TCA)作为手性参照物,分别以Cu2+和H+为中心离子,对苯丙氨酸(Phe)对映体进行手性识别研究.通过离子键合二聚体[Cu2+(18-C-6-TCA)(Phe)-H+]+和(18-C-6-TCA)(Phe)H+的碰撞诱导解离(CID)反应,总结了上述非对映异构体离子的裂解特征并以其初级产物离子与母离子的相对丰度为依据对Phe对映体进行手性识别.通过实验发现,作为过渡金属代表的Cu2+离子对多齿型配体具有较强的配合能力,Cu2+与Phe对映体形成的非对映异构离子[Cu2+(18-C-6-TCA)(Phe)-H+]+离子的稳定性差异较大,手性识别能力较强.同时,[Cu2+(18-C-6-TCA)(Phe)-H+]+的CID反应只产生[Cu2+(18-C-6-TCA)-H+]+产物离子,而(18-C-6-TCA)(Phe)H+的CID反应除了产生质子化的18-C-6-TCA以外,还有冠醚离子的次级碎片产物.这说明18-C-6-TCA、Phe与Cu2+的键合情况以及亲和势都与H+的情形完全不同.本文将结合量化计算对这一点进行详细讨论.
The chiral crown ether (+) - 2,3,11,12-tetracarboxy-18-crown-6 (abbreviated as 18-C-6-TCA) was used as a chiral reference. Cu2 + and H + (Phe) -H +] + and (18-C-6) were synthesized by ion-bonding dimers [Cu2 + (18-C-6-TCA) -TCA) (Phe) H +, the cleavage characteristics of the above diastereomeric ions are summarized and the Phe enantiomer is reported on the basis of the relative abundance of its primary product ions and parent ions (Cu2 + (18-C- (18-C-1-pyrazol-2-yl) 6-TCA) (Phe) -H +] + ions showed a great difference in their stability, while their chiral recognition ability was strong. Meanwhile, the CID response of [Cu2 + (18-C-6-TCA) (Phe) -H +] + The CID reaction of (18-C-6-TCA) (Phe) H + results in the formation of [Cu2 + (18-C-6-TCA) -H +] + product ions in addition to the protonated 18-C-6-TCA, As well as the secondary fragment products of crown ether ions, indicating that the bonding and affinity of 18-C-6-TCA and Phe with Cu 2+ are totally different from that of H + This is discussed in detail.