Studies on the covalent attachment of dyes onto the layer of silylated graphite oxide and their fluorescence properties

用不同的硅烷化试剂成功地实现了氧化石墨的硅烷化。用1-丙二醛和3-氨基丙基三乙氧基硅烷反应得到的染料，在不同链长的烷基三氯硅烷硅烷化的氧化石墨层上共价键合了二茂铁发色团。由上述物质的水解生成的1-丙二醛的吸附测定了所附着的芘的量，达到每8个碳的氧化石墨单元0.7个。只有当氧化石墨层中的烷基链呈双层取向时，芘发色团才会发生聚集。这表明，附着在同一氧化石墨层上的芘分子几乎不会聚集。氧化石墨层中的最大单体芘含量达到0.45个/氧化石墨单元。含氨基的硅烷化氧化石墨与1-吡喃丁二酸丁二酰基酯反应，还连接了基团为Py的发色团。在这个体系中，由于排除了导致自吸收的C=N键，所以荧光变得更强。用振动能较低的全氟烷基链取代烷基后，染料的无辐射跃迁减少，导致荧光增强。

Graphite oxide was successfully silylated by various silylating reagents. Pyrene chromophores were covalently attached onto the layer of graphite oxides silylated by alkyltrichlorosilanes with various alkyl chain lengths using a dye prepared from the reaction between 1-pyrenecarboxaldehyde and 3-aminopropyltriethoxysilane. The amount of attached pyrene was determined from the absorption of 1-pyrenecarboxaldehyde formed as the result of hydrolysis of the above materials and it reached 0.7 per 8 carbons of graphite oxide unit. The aggregation of pyrene chromophores occurred only when the alkyl chains in the layer of graphite oxide took bilayer orientation. This suggests that pyrene molecules attached on the same graphite oxide layer hardly aggregate. The maximum amount of monomeric pyrene in the layer of graphite oxide reached 0.45 per graphite oxide unit. Pyrene chromophores were also attached by the reaction between 1-pyrenebutannoic acid succimidyl ester and silylated graphite oxide containing amino groups. In this system, the fluorescence became stronger because C=N bonding causing self absorption was excluded. The substitution of alkyl chains by perfluoroalkyl chains with lower vibration energy also resulted in the increase of fluorescence since the radiationless transition from dyes decreased.