Synthesis and Structure of a 2, 8, 9‐Trioxa‐3, 5, 7‐trisila‐1‐titanaadamantane

The title compound has been prepared from [Ti(η 5 ‐C 5 Me 5 )Cl 3 ] and cis‐cis‐( t ‐BuSi(OH)—CH 2 ) 3 in hexane solution in the presence of Et 3 N. The pale yellow complex was characterized by NMR and MS spectra, as well as by a crystal structure determination. The two crystallographic independent molecules in the triclinic unit cell (space group P 1¯, No. 2, Z = 4) both have a nearly identical adamantane‐like TiO 3 Si 3 C 3 cage of approximate C 3v symmetry. The exocyclic C—C—C bond angles in the Cp‐ligand range from 123° to 129°. A quantum chemical calculation of the free molecule predicts this range to be 124° to 127°. The arrangement of the molecules in the crystal is characteristic for an offset face‐to‐face ππ stacking of the aromatic η 5 ‐C 5 Me 5 rings.