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Hydrolysis of the ferriochlorosilanes C5R5(OC)2Fe−SiMe2Cl [R = H (1a), Me (1b)] in the presence of Et3N yields the corresponding ferriosilanols C5R5(OC)2Fe−SiMe2(OH) (2a and 2b). In addition, 2b is also obtained by oxo‐functionalization of C5Me5(OC)2Fe−SiMe2H (3) with dimethyldioxirane. The ferriosilanol 2a can be converted into the ferriodisiloxanes Cp(OC)2Fe−SiMe2OSiR3 [R3Si = Me2(H)Si (5a), pTol2(H)Si (5b), Me3Si (5c) and pTol(Me)(H)Si (5d)] by condensation with the chloro(organo)silanes R3SiCl (4a−d). Irradiation of 5a and 5b results in CO elimination, followed by dimerization to give the cyclic 1,5‐diferratetrasiloxanes [µ2‐SiMe2OSi(R)2]2 [Fe(H)(CO)Cp]2 [R = Me (6a) and pTol (6b)]. Compounds 2b and 6b have been characterized by single‐crystal X‐ray structure determination. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Chemical Kinetics I Chemical Oscillations I Electrochemistry I Nonequilibrium Phenomena I Nonlinear PhenomenaWe built a true alternating current (a.c.) battery that periodically reverses value and sign of its electromotive force (e.m.f.). This a.c. battery is an electrochemical concentration cell that consists of two coupled half cells in which identical oscillating Belousov-Zhabotinskii (BZ) reactions take place isothermally at 28.0"C. The homogeneous BZ oscillations are phase shifted in order to create a potential difference between both half cells. With an increasing load the phase shift between the two half cells decreases (i.e. both oscillations tend to synchronize), consequently the amplitude of the alternating current decreases while the amplitudes of the individual BZ-oscillators remain unaffected. The e.m.f.-current diagram of the a.c. battery is analogous to that of direct current batteries. Although the present frequency (period of -58 s), current (-42.5 FA), emf. (-+50 mV) and maximum power produced (-lo-' W) are low it should be possible to construct ax. batteries with improved performances by the use of other chemical oscillators.

Hydrolysis of organotrichlorosilanes RS1CI3 leads to organosilanetriols RSi(OH)3, which usually undergo rapid condensation to siloxanes.2 When bulky ligands are attached to the silicon, it is possible to isolate and characterize organosilanetriols.3 Recently, the first silanetriols attached to transition metals L"M-Si(OH)3 [L"M = (OC)(Cl)(Ph3P)2Os4 and Cp(OC)2-Fe5] have been obtained from hydrolysis of the corresponding trichlorosilyl complexes, indicating that metal fragments can stabilize silanetriols. The stabilization is derived not only from steric effects of the metal group but also from its electron donation to the silicon. The hydrolysis route is limited by the fact that electron-rich metal fragments reduce substitution rates at silicon, a situation observed for the metallotrichlorosilanes C5R5(OC)2(Me3P)M-