posted on 2010-08-18, 00:00authored bySelvan Demir, Sara E. Lorenz, Ming Fang, Filipp Furche, Gerd Meyer, Joseph W. Ziller, William J. Evans
Investigation of the bis(tetramethylcyclopentadienyl) metallocene chemistry of scandium has revealed that the method involving reduction of trivalent salts with alkali metals used with lanthanides can also be applied to scandium to make a dinitrogen complex of the first member of the transition metal series. ScCl3 reacts with 2 equiv of KC5Me4H to form (C5Me4H)2ScCl(THF), 1, which reacts with allylmagnesium chloride to make (C5Me4H)2Sc(η3-C3H5), 2. Complex 2 reacts with [HNEt3][BPh4] to yield [(C5Me4H)2Sc][(μ-Ph)BPh3], 3, which has just one primary Sc−C(phenyl) contact connecting the tetraphenylborate anion and the metallocene cation. Treatment of 3 with KC8 in THF under N2 generates [(C5Me4H)2Sc]2(μ-η2:η2-N2), which has a coplanar arrangement of scandium and nitrogen atoms within a square planar array of tetramethylcyclopentadienyl rings. Density functional calculations explain the bonding that results in the 1.239(3) Å N−N bond distance in the (NN)2− moiety.