Li Zi-Bo, Lin Jing, Sabat Michal, Hyacinth Marilise, Pu Lin
Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA.
J Org Chem. 2007 Jun 22;72(13):4905-16. doi: 10.1021/jo0704715. Epub 2007 May 27.
The cyclohexane-1,2-diamine-based bisbinaphthyl macrocycles (S)-/(R)-5 and their cyclic and acyclic analogues are synthesized. The interactions of these compounds with various chiral acids are studied. Compounds (S)-/(R)-5 exhibit highly enantioselective fluorescent responses and high fluorescent sensitivity toward alpha-hydroxycarboxylic acids and N-protected amino acids. Among these interactions, (S)-mandelic acid (10(-3) M) led to over 20-fold fluorescence enhancement of (S)-5 (1.0 x 10(-5) M in benzene/0.05% DME) at the monomer emission, and (S)-hexahydromandelic acid (10(-3) M) led to over 80-fold fluorescence enhancement. These results demonstrate that (S)-5 is useful as an enantioselective fluorescent sensor for the recognition of the chiral acids. On the basis of the study of the structures of (S)-5 and the previously reported 1,2-diphenylethylenediamine-based bisbinaphthyl macrocycle (S)-4, the large fluorescence enhancement of (S)-5 with a chirality-matched alpha-hydroxycarboxylic acid is attributed to the formation of a structurally rigidified host-guest complex and the further interaction of this complex with the acid to suppress the photoinduced electron-transfer fluorescent quenching caused by the nitrogens in (S)-5.
合成了基于环己烷 - 1,2 - 二胺的双萘基大环化合物（S）-/（R）-5及其环状和非环状类似物。研究了这些化合物与各种手性酸的相互作用。化合物（S）-/（R）-5对α - 羟基羧酸和N - 保护氨基酸表现出高度对映选择性荧光响应和高荧光灵敏度。在这些相互作用中，（S）-扁桃酸（10⁻³ M）使（S）-5（在苯/0.05% 二甲醚中为1.0×10⁻⁵ M）在单体发射时的荧光增强超过20倍，而（S）-六氢扁桃酸（10⁻³ M）使荧光增强超过80倍。这些结果表明（S）-5可作为对映选择性荧光传感器用于识别手性酸。基于对（S）-5结构的研究以及先前报道的基于1,2 - 二苯基乙二胺的双萘基大环化合物（S）-4，（S）-5与手性匹配的α - 羟基羧酸的大荧光增强归因于形成了结构刚性化的主客体复合物，以及该复合物与酸的进一步相互作用，以抑制由（S）-5中的氮引起的光诱导电子转移荧光猝灭。
