Solution Synthesis, Structure, and CO Reduction Reactivity of a Scandium(II) Complex, {Sc[N(SiMe ) ] }<sup/>

The first crystallographically characterizable complex of Sc , [Sc(NR ) ] (R=SiMe ), has been obtained by LnA /M reactions (Ln=rare earth metal; A=anionic ligand; M=alkali metal) involving reduction of Sc(NR ) with K in the presence of 2.2.2-cryptand (crypt) and 18-crown-6 (18-c-6) and with Cs in the presence of crypt. Dark maroon [K(crypt)] , [K(18-c-6)] , and [Cs(crypt)] salts of the [Sc(NR ) ] anion are formed, respectively. The formation of this oxidation state of Sc is also indicated by the eight-line EPR spectra arising from the I=7/2 Sc nucleus. The Sc(NR ) reduction differs from Ln(NR ) reactions (Ln=Y and lanthanides) in that it occurs under N without formation of isolable reduced dinitrogen species. [K(18-c-6)][Sc(NR ) ] reacts with CO to produce an oxalate complex, {K (18-c-6) }{[(R N) Sc] (μ-C O -κ O:κ O'')}, and a CO radical anion complex, [(R N) Sc(μ-OCO-κ O:κ O')K(18-c-6)] .