Ti and Zr complexes of ferrocenyl amidinates

Preparation of a N-ferrocenyl-amidinate complex was achieved by employing (TMEDA)Li[(CpFeC5H4)NC(Ph)NSiMe3] (1) to prepare Cp*Zr[(CpFeC5H4)NC(Ph)NSiMe3]Cl-2 (2). Complex 2 exhibited poor polymerization activity and thus a series of C-ferrocenyl bis(amidinate) complexes of the type M(L)2Cl(2) (M = Zr, 4; M = Ti, 5; L = (CyNC(CpFeC5H4)NCy) were synthesized via reaction of ferrocenyl-amidine, H(L) and M(NMe2)(2)Cl-2 (M = Ti, Zr center dot 2THF). Half sandwich mono(amidinate) complexes, Cp'ZrLCl2] (Cp' = Cp, 7; Cp' = Cp*, 8), were prepared by the reaction of Cp'ZrCl3 with Li(L) and subsequently alkylated to give M(L)(2)Me-2 (M = Zr, 9; M = Ti, 11), CpZr(L)(CH2Ph)(2) (12) and Cp* Zr(L) Me-2 (10) with the appropriate alkylating agent. Abstraction of a methyl group from 7 with B(C6F5)(3) and [Ph3C][B(C6F5)(4)] proceeded cleanly to give [{CyNC(CpFeC5H4)NCy}(2)ZrMe][MeB(C6F5)(3)] 13 and [{CyNC(CpFeC5H4) NCy} 2ZrMe][B(C6F5)(4)] 14, respectively. Similarly, the analogous CpZr and Cp* Zr derivatives LZr{CyNC(CpFeC5H4)NCy} CH2Ph] [PhCH2B(C6F5) 3] L = Cp 15, Cp* 17 and [LZr{CyNC(CpFeC5H4)NCy}CH2Ph][B(C6F5)(4)] L = Cp 16, Cp* 18 were prepared. Cyclic voltammetry studies on the metal complexes containing ferrocenyl-amidinates reveal quasi reversible oxidation and reduction waves for the ferrocene/ferrocenium couple. The dichloride complexes (4-8) activated with MAO and dialkyl complexes (9,10) activated with B(C6F5)(3) and [Ph3C][B(C6F5)(4)] showed low ethylene polymerization activities.