Synthesis, Structure, and Density Functional Theory Analysis of a Scandium Dinitrogen Complex, [(C₅Me₄H)₂Sc]₂(μ-η²:η²-N₂)

Abstract

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. ScCl(3) reacts with 2 equiv of KC(5)Me(4)H to form (C(5)Me(4)H)(2)ScCl(THF), 1, which reacts with allylmagnesium chloride to make (C(5)Me(4)H)(2)Sc(eta(3)-C(3)H(5)), 2. Complex 2 reacts with [HNEt(3)][BPh(4)] to yield [(C(5)Me(4)H)(2)Sc][(mu-Ph)BPh(3)], 3, which has just one primary Sc-C(phenyl) contact connecting the tetraphenylborate anion and the metallocene cation. Treatment of 3 with KC(8) in THF under N(2) generates [(C(5)Me(4)H)(2)Sc](2)(mu-eta(2):eta(2)-N(2)), 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) A N-N bond distance in the (N=N)(2-) moiety.