Preparation of bifluorenes via the synthesis and thermal decomposition of fluorenyltitanium(IV) trichlorides. Molecular and crystal structure of 9,9 '-bis(trimethylsilyl)-bi-9,9 '-fluorene

The reaction of B-substituted trimethyltinfluorenes with TiCl4 in hexanes a t -40 degrees C leads to unstable fluorenyltitanium(IV) trichlorides which thermal radical decomposition gives quantitatively TiCl4 and corresponding bifluorenes: (C13H9)(2) (3a), (9-EtC13H8)(2) (3b) and (9-SiMe3C13H8)(2) (3c ). Crystals of 3c are monoclinic (space group P 2(1)/n), a= 15.059 Angstrom , b= 10.254 Angstrom, c= 18.172 Angstrom, beta= 109.20 deg. IIIc dissociate s at 100 degrees C to give two radicals which initiate effectively radical polymerizations of methyl methacrylate and styrene. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.