Synthesis of zirconium complexes that contain a tridentate diamido ligand

The triamine t-BuNHSiMe2NHCH2CH2NMe2 (1; =H-2[NSiN2]) was synthesized from LiNHCH2CH2NMe2 and t-BuNHSiMe2Cl and used without purification to produce [NSiN2]Zr(NMe2)(2) (2) from Zr(NMe2)(4). Addition. of excess trimethylsilyl chloride to 2 gave [NSiN2]ZrCl2 (3). Dialkyl complexes of the type [NSiN2]ZrR2 (R = CH2SiMe3, CH2Ph, CH2CHMe2) were prepared readily by alkylation of 3. The structure of a magnesium chloride adduct ofthe diisobutyl derivative showed it to be a dimer, {[NSiN2]Zr(CH2CHMe2)(2)MgCl2}(2), which contains a ZrN(Cl)MgCl2MgN(Cl)Zr backbone. [NSiN2]Zr(CH2CHMe2)(2) proved to be inactive for the polymerization of I-hexene when activated by either [PhNMe2H][B(C6F5)(4)] or [Ph3C][B(C6F5)(4)] in chlorobenzene at 0 degrees C.