Bis(phosphinimino)methanides as ligands in divalent samarium chemistry: Synthesis, structures and catalysis

The reaction of K{CH(PPh2NSiMe3)(2)} with samarium diiodide in a 1:1 molar ratio in thf affords the corresponding divalent samarium complex [{(Me3SiNPPh2)(2)CH}Sm(mu-I)(thf)](2) (1), whereas treatment of K(CH(PPh2NSiMe3)21 with samarium diiodide in a 2:1 molar ratio in thf gives the homoleptic complex [{(Me3SiNPPh2)(2)CH}(2)Sm] (2). When 1 is treated with KNPh2 in toluene in a 2:1 molar ratio the mixed dimeric compound [({(Me3SiNPPh2)CH}(2)Sm)(2) (mu-I) (mu-NPh2)] (3) is obtained. The single-crystal X-ray structures of all these complexes have been determined. [{(Me3SiNPPh2)(2)CH}Sm(mu-I)(thf)](2) has also been successfully used as a catalyst for the polymerization of E;-caprolactone. Good activities and molecular masses are observed with this catalyst. (c) Wiley-VCH Verlag GmbH & Co. KGaA.