Construction of fullerene-coated nano-structures using alkylfullerenyl cations

1.烷基富勒烯阳离子热力学稳定性的定量测定通过对氯化物R-C_ -Cl的S_N1溶剂分解动力学的测定和富勒烯醇R-C_ -OH电离平衡常数的精确测定，评价了烷基富勒烯阳离子的热力学稳定性<60><60>。这些实验结果表明，烷基富勒烯阳离子具有与叔丁基阳离子相当的稳定性。2.长寿命烷基富勒烯阳离子的制备及其盐分离由于<60>C_2笼的电负性，C_2阳离子的分离一直被认为是极其困难<60>的。然而，在本研究中，<60>用银离子（AgSbF_6）或用刘易斯酸（SbCl_5）处理氯化物R-C_ -Cl，成功地制备了RC_<60>^+，在中性有机溶剂中以稳定溶液的形式或以盐RC_<60>^+ SbCl_5^-的形式存在。以前，这些阳离子只能在强酸性溶剂中以溶液的形式制备。3.用烷基富勒烯基阳离子在二氧化硅表面包覆富勒烯单分子膜通过将硅片浸入R-C_ -Cl溶液中，可以在硅片表面制备富勒烯<60>单分子膜。这可以解释为中间阳离子RC_<60>^+与氧化物层表面上的羟基反应的结果。这表明RC ^+的高反应活性<60>有助于在表面<60>覆盖有羟基的固体表面上形成C单层。

1.Quantitative Determination of the Thermodynamic Stabilities of Alkylfullerenyl CationsThe thermodynamic stabilities of alkylfullerenyl cations were evaluated by the kinetic measurements for the S_N1 solvolysis of chlorides R-C_<60>-Cl and by precise determination of the equilibrium constants of the ionization of fullerenols R-C_<60>-OH. The results of these experiments demonstrated that alkylfullerenyl cations have stabilities comparable to that of the tert-butyl cation.2.Preparation of Alkylfullerenyl Cation as Long-lived Species in Solution and Its Isolation as a SaltThe isolation of C_<60> cations have been considered extremely difficult, owing to the electronegative nature of the C_<60> cage. In the present study, however, treatment of chlorides R-C_<60>-Cl with silver ion (AgSbF_6) or with a Lewis acid (SbCl_5) resulted in successful preparation of RC_<60>^+ the form of a stable solution in neutral organic solvent or in the form of a salt RC_<60>^+ SbCl_5^-. Formerly, these cations could be prepared only as solutions in strongly acidic solvents.3.Coating of Silica Surface with Fullerene Monolayer using Alkylflullerenyl CationA monolayer of fullerene could be prepared on the surface of silicon wafer, by dipping the wafer in a solution of R-C_<60>-Cl. This can be interpreted as a result of the reaction of an intermediate cation RC_<60>^+ with hydroxyl groups on the surface of the oxide layer. This observation demonstrated that the high reactivity of RC_<60>^+ would be useful for the formation of a C_<60> monolayer on solid surfaces covered with hydroxyl groups.