Nowadays, increasing attention is paid to films of polymer chains covalently bonded to solid surfaces. [1,2] This strategy is very useful to modify the surface properties of inorganic materials, to improve the interfacial bonding in composites, and to prepare novel inorganic ± organic hybrids. [3, 4] In addition to this technique that consists of the chemical bonding of preformed end-reactive chains to the surface (ªgrafting ontoº method), polymer brushes can be formed by the ªgrafting fromº method, that is, the initiation and growth of the chains from the solid surface. When this substrate is electrically conducting, electropolymerization has proved to be a powerful method to deposit polymers that highly adhere to the substrate. [5±7] Indeed, the electroreduction of monomers of the (meth)acrylate type at an appropriate potential leads to the rapid formation of an homogeneous polymer film on the cathode whatever its shape (plate, fiber) and nature (metal, carbon, indium tin oxide (ITO) glass). [8, 9] That the polymer is chemisorbed onto the substrate is confirmed by insolubility in a good solvent for the polymer and by peeling tests. [10, 11] However, as a result of the formation of an insulating poly(meth)acrylate film on the cathode, the substrate is rapidly passivated (rendered inactive) which limits the film thickness (`100 nm). Moreover, monomers that contain protic functions (alcohol, amine, carboxylic acid, etc.) cannot be electrografted because of their reduction at the same or at a less cathodic potential than the (meth)acrylate.
The recent development of well-defined and highly active catalysts by the groups of Schrock [12] and Grubbs, [13] has also reactivated interest in the ring-opening metathesis polymerization (ROMP) of cycloolefins, particularly for applications in solid-phase chemistry. [14±17] Therefore, a combination of living ROMP and electrografting appears to be a promising strategy to overcome the limitations of the electrografting process. Indeed, the thickness of the polymer film ªgraftedº to the electrode could be easily tuned by a second step of ªgrafting fromº polymerization of cycloolefins. Moreover, advantage can be taken of the compatibility of the Grubbs above yielded 6 b (0.49 g, 92 %) as red microcrystals; 1 H NMR (500 MHz, CDCl 3 ): d 7.1 ± 7.4 (m, 5 H; SCH 2 Ph), 4.63 (d, J 12.5 Hz, 1 H; SCH 2 Ph), 4.33 (d, J 12.5 Hz, 1 H; SCH 2 Ph), 2.23 (s, 15 H; Cp*); IR (Nujol): n Ä 911 (WO), 482 (WS) cm À1 ; EI-MS; m/z 490 [M ], 399 [M À CH 2 Ph]; elemental analysis calcd (%) for C 17 H 22 OS 2 W: C 41.64, H 4.52