D-,L-苯丙氨酸诱导非手性菁染料的手性组装

Chiral assembly of achiral pseudoisocyanine with D-and L-phenylalanine

超分子手性与分子自组装是生命体中非常重要和有趣的现象.报道了D,L-苯丙氨酸等氨基酸在氯化钠溶液中通过非共价键相互作用诱导非手性菁染料(Pseudoisocyanine,PIC)J-聚集体超分子手性的形成.实验结果表明,诱导的手性菁染料PIC聚集体发色团在π-π*跃迁区域产生了特征的镜像圆二色性,其圆二色信号和强度强烈地依赖于氨基酸的绝对构型、浓度、侧链基团和溶液温度.原子力显微镜照片清楚地表明,J-聚集体由相互交联的纳米纤维组成,诱导的圆二色性可能来源于纤维状聚集体的宏观螺旋排列.

Supramolecular chirality and molecular self-assembly are important and interesting phenomenon in living and non-living systems. In this paper, supramolecular chirality of achiral pseudoisocyanine （PIC） J-aggregates was successfully induced by D-, L-phenylalanine （Phe） and other amino acids in NaCI solution. The chiral J-aggregates show a characteristic, induced circular dichroism （ICD） in visible region of J-band chromophore which depends on the absolute configuration, concentration and side groups of α-amino acids, as well as temperature. The atomic force microscopy images indicated that the J-aggregates exist in large bundles of entangled nanofibers, the observed ICD might result from the macroscopic helical arrangement of the assemblies.