Metallacyclodisiladiazanes of Titanium and zirconium; Synthesis, Structure and Polymerization Studies

A series of metallacyclodisiladiazanes has been prepared. Lithiated (SiMe 2 NH t Bu) 2 ( 1 ) reacts with TiCl 4 · 2 THF to give (SiMe 2 N t Bu) 2 TiCl ( 4 ). Methylation or fluorination of 4 leads to (SiMe 2 N t Bu) 2 TiMe 2 ( 8 ) and (SiMe 2 M t Bu) 2 TiF 2 ( 9 ), respectively. The reaction of ZrCl 4 · 2 THF with lithiated 1 or [SiMe 2 NH(4‐FC 6 J 4 )] 2 ( 2 ) yields (SiMe 2 N t Bu) 2 ZrCl 2 ( 5 ) and [SiMe 2 N(4‐FC 6 H 4 )]ZrCl 2 · THF ( 7 ), respectively. The lithiated ligand [SiMe 2 NH(2,6‐ i Pr 2 C 6 H 3 )] 2 ( 3 ) reacts with noncoordinated ZrCl 4 to give [SiMe 2 N(2,6‐ i Pr 2 C 6 H 3 )] 2 ZrCl 2 ( 6 ). X‐ray structural analysis of 9 showed it to be a fluorine‐bridged dimer in the solid state. Compounds 4, 6, 8 and 9 were found to be catalysts for the polymerization of ethylene.