1,1,3,3-tetramethyl-1,3-disila-2-oxa[3]ferrocenophane: improved synthesis and new crystal structure

1,1,3,3-Tetramethyl-1,3-disita-2-oxa[3]ferrocenophane Fe(eta(5)-C5H4)(2)[Si(CH3)(2)](2)O (1) has been prepared by using an improved method, a reaction of 1,1'-dilithioferrocene-TMEDA with dichlorodimethylsilane followed by hydrolysis. The yield was clearly increased in comparison to the methods known from literature. A new polymorph crystal structure 1A of compound I was determined by single-crystal X-ray diffraction at 110 K. Crystals were obtained by slow evaporation of chloroform. Complex 1A crystallises in the orthorhombic space group P2(1)2(1)2(1) with the following cell constants: a = 8.498(2), b = 11.389(2), c = 15.448(3) Angstrom, alpha = 90degrees, beta = 90degrees, gamma = 90degrees, V = 1495.115 Angstrom(3) and Z = 4. (C) 2002 Elsevier Science B.V. All rights reserved.