Synthesis, structure and reactivity of scandium bis(trimethylsilyl)amido derivatives

The synthesis of scandium complexes supported by two bis(trimethylsilyl)amido ligands and their reactivity to generate a variety of organometallic derivatives is reported. The monomeric scandium complex Sc{N(SiMe3)(2)}(2)(THF)Cl, 1, and the ate complex Sc(N(SiMe3)(2))(2)Cl2Li(THF)(3), 2, were generated by salt metathesis routes from ScCl3(THF)(3) and LiN(SiMe3)(2). Complex 1 reacts cleanly with MeLi or KCH2Ph to form the compounds Sc{N(SiMe3)(2)}(2)(THF)R, (R = Me, 3; CH2Ph, 4), respectively. Upon reaction of 1 with bulky lithium reagents such as LiCH2SiMe3 or TripLi, cyclometalation at scandium occurs to generate the bimetallic species Sc{N(SiMe3)(2))(2)(mu-CH2)(2)Sc{N(SiMe3)SiMe2}(2)(THF), 5. Finally, the scandium iodide congener Sc{N(SiMe3)(2)}(2)(THF)I, 6, was produced by reaction of 3 with the iodide transfer reagent [Et3NH]I. Attempts to access a low valent scandium complex, by reduction of 6 with either KC8 or [(nacnac) Mg](2), where nacnac = (2,6-Pr-i(2)-C6H3)NC(Me)CHC(Me)N(2,6-Pr-i(2)-C6H3) failed to afford well-defined low valent organometallic scandium species. All compounds were characterized by single crystal X-ray diffraction studies. (C) 2015 Elsevier Ltd. All rights reserved.