REACTIONS OF TITANOCENE DERIVATIVES WITH MOLECULAR CARBOXYLIC-ACIDS AND COPOLYMERS BEARING CARBOXYLIC-ACID GROUPS

Linear, soluble copolymers containing titanium are of interest for use in targets for inertfal-confinement fusion (ICF) experiments because the titanium is a useful spectroscopic probe for studying the nuclear fusion process, We have studied the reactions of dichloro-titanocene a nd diphenyltitanocene with carboxylic acids to determine if these can be used to prepare such polymers, Model reactions of dichlorotitanocen e with p-toluic acid show that both mono- and di-carboxylates are form ed, We have prepared a soluble titanium-containing copolymer via the r eaction of poly(styrene-co-methacrylic acid) with an excess of dichlor otitanocene but attempts to remove the excess molecular titanocene fro m the copolymer result in crosslinking of the copolymer, Model reactio ns of benzoic and pivalic acids with diphenyltitanocene demonstrate th at monosubstituted carboxylato(phenyl)titanocenes are formed but that these products are stable only at low temperatures and decompose readi ly at ambient temperature, Proton NMR studies of the reaction of diphe nyltitanocene and benzoic acid at - 20 degrees C indicate that this re action is second order, suggesting that the reaction does not proceed through a benzyne intermediate. (C) 1997 by John Wiley & Sons, Ltd.