Organozirconium(III)–dinitrogen complexes: evidence for (η2-N2)–metal bonding in [Zr(η-C5H5)2(N2)(R)][R = Me3Si)2CH]

Abstract

Reduction of [Zr(η-C₅H₅)₂(Cl)R][R =(Me₃Si)₂CH] with Na–Hg in tetrahydrofuran (THF) under ¹⁴N₂ affords brown, paramagnetic, air-sensitive, crystalline [Zr(η-C₅H₅)₂(¹⁴N₂)R], which in THF shows an e.s.r. 1:2:3:2:1 quintet due to coupling [a(¹⁴N)= 0·375 mT] with two equivalent ¹⁴N atoms [or a 1:2:1 triplet for the ¹⁵N₂-isotopomer, a(¹⁵N)= 0·45 mT], and no i.r. absorption in the 2400–1500 cm^–1 region; one half of the N₂ is gradually lost at ca. 20 °C and 10^–3 mmHg to yield purple crystals (from PhMe) of [{Zr(η-C₅H₅)₂R}₂N₂].