Assembly of Platinum Diimine Dithiolate Complexes onto Hydrogen-Terminated Silicon Surfaces

作者：Yzambart Gilles; Fabre Bruno^*; Roisnel Thierry; Dorcet Vincent; Ababou Girard Soraya; Meriadec Cristelle; Lorcy Dominique

来源：Organometallics, 2014, 33(18): 4766-4776.

DOI：10.1021/om5000369

The synthesis and structural characterization of the platinum diimine dithiolate complexes [Pt(R(2)bipy)(dmipi)] (dmipi = 4,5-dimercapto-1,3-dithiol-2-propargylimino and R = H, tBu) are described together with the X-ray crystal structure of the dithiolate proligand. These heteroleptic Pt complexes have been covalently bound to hydrogen-terminated silicon (100) surfaces using either a one-step or two-step procedure. The redox-active organometallic film modified surfaces were prepared from a hydrosilylation reaction at 90 degrees C of either the Pt complex bearing an ethyne terminal group or an ethyne-terminated dithiolate precursor followed by the subsequent anchoring of the Pt complex. Cyclic voltanimetry measurements showed the presence of a single reversible one-electron-oxidation process corresponding to the oxidation of the complex into its radical cation species at 0.42 and 0.46 V vs SCE for the unsubstituted and tBu-substituted bipyridine dithiolate Pt complex-modified Si(100) surfaces, respectively. Such values compare well with those determined for the electroactive molecules in solution. Moreover, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements were consistent with the expected structure of grafted molecular chains and revealed a significant oxidation of the underlying silicon surface. Nevertheless, the one-step procedure was found to lead to redox-active films of density higher than those produced from the two-step procedure. From XPS data, the surface coverage was estimated at 0.10 and in the range 0.03-0.06 Pt complex per surface silicon atom for the one-step and two-step procedures, respectively.

• 出版日期2014-9-22