Ferrocenylethenylsilatranes and a cymantrenylsilatrane

The syntheses, properties and crystal structures of two isomeric ferrocenyl ethenylsilatranes and 1-(3-methylcymantrenyl)silatrane are reported. The or ganometallic moieties and the silatrane show little structural influence on each other. The Si-N distances remain in the expected range of 2.13-2.22 A ngstrom, asserting the hypervalency of silicon. The electron-donating effec t of the silatrane group is transmitted through the C-C double bond to ferr ocene, as shown by the redox potentials. The first hyperpolarizability of t he ferrocene derivatives was determined by hyper-Rayleigh scattering. (C) 1 999 Elsevier Science S.A. All rights reserved.