Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, People's Republic of China.
Langmuir. 2012 Jul 31;28(30):11153-63. doi: 10.1021/la301338a. Epub 2012 Jul 17.
Self-assembly and molecular recognition of the monolayers composed of an equimolar mixture of adenine- and thymine-functionalized nucleolipids at the air-water interface have been investigated in detail using surface pressure-molecular area isotherms and in situ infrared reflection absorption spectroscopy (IRRAS). Prior to molecular recognition, the adenine moieties in the monolayer were almost oriented on an end-on mode through π-stacking and hydrogen bonding interactions, and the C-C-C planes of the alkyl chains were preferentially oriented perpendicular to the water surface, while the thymine moieties in the monolayer were involved in hydrogen bonding almost with a flat-on orientation. On aqueous subphases containing complementary bases, no significant molecular recognition was observed for the monolayers of individual nucleolipids. In the monolayer of equimolar mixture, molecular recognition occurred between the adenine and thymine moieties through hydrogen bonding probably with the development of cyclic structures of adenine-thymine-adenine-thymine quartets. Although molecular recognition between the monolayer of thymine-functionalized nucleolipids and aqueous melamine took place through triple hydrogen bonds, no melamine binding to the monolayer of equimolar mixture was observed, which reflects the formation of the quartets in the mixed monolayers at the air-water interface. FTIR and small-angle X-ray diffraction (XRD) results of the corresponding Langmuir-Blodgett films support the hydrogen bonding recognition and molecular orientation.
在气液界面，通过表面压力-分子面积等温线和原位红外反射吸收光谱（IRRAS）详细研究了由腺嘌呤和胸腺嘧啶功能化的核脂质体等摩尔混合物组成的单层的自组装和分子识别。在分子识别之前，单层中的腺嘌呤部分通过π-堆积和氢键相互作用几乎以末端模式取向，并且烷基链的 C-C-C 平面优先垂直于水面取向，而单层中的胸腺嘧啶部分几乎以平卧取向参与氢键。在含有互补碱基的水亚相中，对于单个核脂质体的单层，没有观察到明显的分子识别。在等摩尔混合物的单层中，通过氢键可能形成腺嘌呤-胸腺嘧啶-腺嘌呤-胸腺嘧啶四重体的循环结构，发生了腺嘌呤和胸腺嘧啶部分之间的分子识别。尽管通过三氢键发生了胸腺嘧啶功能化核脂质体单层与水合三聚氰胺之间的分子识别，但没有观察到三聚氰胺与等摩尔混合物的单层结合，这反映了在气液界面的混合单层中四重体的形成。相应的 Langmuir-Blodgett 薄膜的 FTIR 和小角 X 射线衍射（XRD）结果支持氢键识别和分子取向。
