957049-89-7Relevant academic research and scientific papers
Monoanionic fac-κ3 ligands derived from 6-amino-1,4-diazepine: Ligand dependence of stability and catalytic activity of their scandium alkyl derivatives
Ge, Shaozhong,Meetsma, Auke,Hessen, Bart
, p. 5278 - 5284 (2008/10/09)
Two new monoanionic fac-κ3 tridentate ligands [6-RN-1,4,6-trimethyl-1,4-diazepine]- (R = CH3, L 1; R = PhMe2Si, L2) were prepared, Reactions of ligands HL1 and HL2 with Sc(CH2SiMe 3)3(THF)2 yielded (L1)Sc(CH 2SiMe3)2(THF) (1) and (L2)Sc(CH 2SiMe3)2(THF) (2), respectively. In toluene solvent, 1 loses a THF molecule and decomposes via metalation of the methyl group of the amido functionality to give {[CH2(μ-N)-1,4,6- trimethyl-1,4-diazepine]Sc(CH2SiMe3)}2 (3), whereas 2 loses a THF molecule to give stable (L2)Sc(CH 2SiMe3)2 (4). In THF, both 1 and 2 react with [PhNMe2H] [B(C6H5)4] to generate the ionic monoalkyl compounds [(L)Sc(CH2SiMe3)(THF) 2][B(C6H5)4] (5, L = L1, 6, L = L2). Nevertheless, only the THF-free system 4/[PhNMe 2H][B(C6F5)4] shows good ethylene polymerization activity, showing that a single THF molecule per Sc suffices to quench the catalysis. Dinuclear 3 reacts with ethylene via stoichiometric insertion into the Sc-CH2N bond to yield {[CH2CH 2CH2(μ-N)-1,4,6-trimethy 1-1,4-diazepine]Sc(CH 2SiMe3)}2 (7).
