Mixed Imidazolin-2-iminato-Cp* Thorium(IV) Complexes: Synthesis and Reactivity Toward Oxygen-Containing Substrates

作者：Karmel Isabell S R; Fridman Natalia; Tamm Matthias^*; Eisen Moris S

来源：Organometallics, 2015, 34(12): 2933-2942.

DOI：10.1021/acs.organomet.5b00273

The mixed pentamethylcyclopentadienyl thorium(IV) imidazolin-2-iminato complexes Cp*Th-2(Im(Dipp)N)(Me) (2) and Cp*Th-2(Im(Mes)N)(Me) (3) were synthesized in quantitative yields via rapid protonolysis of Cp*Th-2(Me)(2) (1) with the respective neutral imidazolin-2-iminato ligand Im(R)NH. Cp*Th-2(Im(Dipp)N)(Me) (2) and Cp*Th-2(Im(Mes)N)(Me) (3) display short ThN bond lengths and large ThNC angles. The reactivity of complex 2 and 3 toward oxygen-containing substrates was studied, and the catalytic activity of 2 was compared to the dimethyl (bispentamethylcyclopentadienyl) thorium complex 1. Complex 2 was applied in the catalytic Tishchenko reaction with aromatic, heteroaromatic, and branched aliphatic aldehydes, displaying a higher catalytic activity than Cp*Th-2(Me)(2) and Cp*2Th(Im(Mes)N)(Me). Furthermore, 2 was applied as a catalyst in the crossed Tishchenko reaction and in the oligomerization of bis(aldehydes), as well as in the ring-opening polymerization of e-caprolactone. In all reactions, the activity of Cp*Th-2(Im(Dipp)N)(Me) (2) and Cp*Th-2(Im(Mes)N)(Me) (3) was higher than that observed for Cp*Th-2(Me)(2) (1), which can be attributed to the increased electron density introduced by the coordination of the imidazolin-2-iminato ligand.

• 出版日期2015-6-22