Thorium(IV) alkyl synthesis from a thorium(III) cyclopentadienyl complex and an N-heterocyclic olefin.

Treatment of the tris(cyclopentadienyl) thorium(III) complex [Th(η 5 -Cp′′) 3 ] [ 1 , Cp′′ = C 5 H 3 -1,3-(SiMe 3 ) 2 ] with the N -heterocyclic olefin H 2 C=C(NMeCH) 2 ( 2 ) reproducibly produces the thorium(IV)-methyl derivative [Th(η 5 -Cp′′) 3 (Me)] ( 3 ) along with MeImCH 2 CH 2 ImMe (Im = imidazole). The reaction mechanism, which is consistent with 1 H NMR spectroscopic observations, is proposed to proceed via: (i) coordination of 2 to 1 ; (ii) one-electron transfer from thorium to 2 ; (iii) N -methyl cleavage and transfer to thorium to give 3 ; (iv) coupling of the resulting imidazolium radical by-product to give MeImCH 2 CH 2 ImMe. Complex 3 has been characterised by single crystal X-ray diffraction, multi-nuclear NMR and IR spectroscopies, and elemental analyses, and MeImCH 2 CH 2 ImMe by 1 H NMR spectroscopy and mass spectrometry. [ABSTRACT FROM AUTHOR]