Reduced Arene Complexes of Scandium.

Alkali metal naphthalenide or anthracenide reacted with scandium(III) anilides [Sc(X){N(tBu)Xy}(2) (thf)] (X=N(tBu)Xy (1); X=Cl (2); Xy=C(6) H(3) -3,5-Me(2) ) to give scandium complexes [M(thf)(n) ][Sc{N(tBu)Xy}(2) (RA)] (M=Li-K; n=1-6; RA=C(10) H(8) (2-) (3-Naph-K) and C(14) H(10) (2-) (3-Anth-M)) containing a reduced arene ligand. Single-crystal X-ray diffraction revealed the scandium(III) center bonded to the naphthalene dianion in a σ(2) :π-coordination mode, whereas the anthracene dianion is symmetrically attached to the scandium(III) center in a σ(2) -fashion. All compounds have been characterized by multinuclear, including (45) Sc†NMR spectroscopy. Quantum chemical calculations of these intensely colored arene complexes confirm scandium to be in the oxidation state +3. The intense absorptions observed in the UV/Vis spectra are due to ligand-to-metal charge transfers. Whereas nitriles underwent C-C coupling reaction with the reduced arene ligand, the reaction with one equivalent of [NEt(3) H][BPh(4) ] led to the mono-protonation of the reduced arene ligand.