Ethene Polymerisation with Titanium Half-Sandwich Amido-Complexes

Abstract

The complexes [CpTi(NR2)3] were tested in ethene polymerisation and the effect of the alkyl-amine groups on their activities was explored.

Metalation Studies on Titanocene Dithiolates

“…Treatment of the known titanocene dichlorides (C 5 H 4 X)(C 5 H 4 Y)TiCl 2 (X = Y = H, 1a; X = H, Y = Cl, 1b; X = Y = Cl, 1c) [33,34] with HS-C 6 H 4 R (R = H, p-Me) in the presence of DABCO (1,4- alkyl lithiums to thermally unstable titanocene alkyls Cp2TiR2, which easily decompose to titanium(III) products [22,23] and with lithium amides to mono-cyclopentadienyl titanium tris-amides CpTi(NR2)3 [24]. In addition, with the often-used base KO t Bu, a mixture of products including those of splitting off the cyclopentadienyl ligands was observed [25].…”

“…Since our synthetic protocol always involves the use of lithium organyls or lithium amides, there was also the need for a proper titanocene starting material. It has been known for a long time that titanocene chlorides react with alkyl lithiums to thermally unstable titanocene alkyls Cp 2 TiR 2 , which easily decompose to titanium(III) products [22,23] and with lithium amides to mono-cyclopentadienyl titanium tris-amides CpTi(NR 2 ) 3 [24]. In addition, with the often-used base KO t Bu, a mixture of products including those of splitting off the cyclopentadienyl ligands was observed [25].…”