Organosilyl/-germyl Polyoxotungstate Hybrids for Covalent Grafting onto Silicon Surfaces: Towards Molecular Memories

摘要

Organosilyl/-germyl polyoxotungstate hybrids [PW₉O₃₄(tBuSiO)₃Ge(CH₂)₂CO₂H]3− (1 a), [PW₉O₃₄(tBuSiO)₃Ge(CH₂)₂CONHCH₂CCH]3− (2 a), [PW₁₁O₃₉Ge(CH₂)₂CO₂H]4− (3 a), and [PW₁₁O₃₉Ge(CH₂)₂CONHCH₂C≡CH]4− (4 a) have been prepared as tetrabutylammonium salts and characterized in solution by multinuclear NMR spectroscopy. The crystal structure of (NBu₄)₃1 aH₂O has been determined and the electrochemical behavior of 1 a and 2 a has been investigated by cyclic voltammetry. Covalent grafting of 2 a onto an n-type silicon wafer has been achieved and the electrochemical behavior of the grafted clusters has been investigated. This represents the first example of covalent grafting of Keggin-type clusters onto a Si surface and a step towards the realization of POM-based multilevel memory devices.