The first unsymmetric monosilanylene-bridged 2,2′-bis(indenyl) system, 1,1′-(2,2′-C 9 H 6 ) 2 -Si(Me)(t-Bu) (3c), was synthesized in the same manner as the disilanylene and disiloxanylene systems. Furthermore, a series of dinuclear complexes with these double-bridged ligands were reacted with appropriate metal fragments, yielding 1 10b) for cobalt. All compounds were obtained as the antifacial isomer, except complex 8a, where a mixture of the syn and anti species was obtained. The redox behavior of 8a was investigated by cyclic voltammetry in CH 2 Cl 2 . The structures of 6b and 8a were determined by X-ray diffractometry.

A series of novel bisindene derivatives 1,1′-(2,2′-C 9 H 6 ) 2 SiPh 2 , 5, 1,1′-(2,2′-C 9 H 6 ) 2 Si 2 Me 4 , 6, and 1,1′-(2,2′-C 9 H 6 ) 2 SiMe 2 OSiMe 2 , 7, bearing an intramolecular monosilanylene, disilanylene, or siloxanylene bridge between the 1,1′-positions were synthesized from the reaction of the dianion of dibenzo[b,e]fulvalene 3 with the corresponding halogen silanes. Introducing a SiMe 2 bridge failed because of the less steric demand of the smaller methyl groups. These polycyclic compounds 6 and 7 were deprotonated twice to react with [(cod)RhCl] 2 , giving the homobimetallic complexes 1,1′-[(η 5 -C 9 H 5 )Rh(cod)] 2 Si 2 Me 4 , 11, and 1,1′-[(η 5 -C 9 H 5 )Rh(cod)] 2 -SiMe 2 OSiMe 2 , 12, as an isomeric mixture of the syn-and antifacial species; 2 and both isomers of 12 were characterized by X-ray crystallography. The compound 5 does not give any related metal complex in this reaction due to both phenyl rings blocking the coordination spheres of the indenyl rings.