[3]FERROCENOPHANES WITH A TETRAMETHYLDISILOXANE BRIDGE - SYNTHESIS AND MOLECULAR-STRUCTURE

,8,8-Tetramethyl-7-oxa-6,8-disila[3]ferrocenophane 2 was obtained from the di(alkoxysilyl) ferrocene (H4C5SiMe2OR)2Fe (R = CH2CH2OCH2CH2OCH2 CH2OMe) by hydrolysis and subsequent intramolecular disiloxane formati on. ,8-Dodecamethyl-7-oxa-6,8-disila-[3]ferrocenophane 3 was formed by air oxidation of ,6,6,7,7-dodecamethyl-6,7-disila[2]ferrocenophane. T he crystal structures of both compounds were determined by single-crys tal X-ray diffraction (2: a = 8.5330(10), b = 15.610(3), c = 18.774(5) angstrom, alpha = 70.68(2), beta = 77.94(2), gamma = 75.150(10)degree s, V = 2259.8(8) angstrom3, Z = 6, space group P1BAR, R = 0.045, R(w) = 0.044; 3: a = 12.388(3), b = 9.924(3), c = 19.136(10) angstrom, beta = 105.11(3)degrees, V = 2271.2(15)angstrom3, Z = 4, space group P2(1) /c, R = 0.076, R(w) = 0.060). Owing to the flexibility of the disiloxa ne bridge, 2 and 3 are unstrained molecules.