New Approach to anionic transition metal alkyls; synthesis and e.s.r. characterisation of the d1 dialkylmetallate(III)'s [M(η-C5H4R1)2R22]–(M = Ti, Zr, or Hf)

Abstract

Sodium naphthalide in tetrahydrofuran (thf) smoothly converts a d⁰ metallocene dialkyl [M(η-C₅H₄R¹)₂R²₂](M = Ti, Zr, or Hf; R¹= H, Me, or Prⁱ; R²= Me, PhCH₂, Me₃CCH₂, Me₃SiCH₂, or Ph₂CH) into the corresponding d¹ dialkylmetallate(III)[M(η-C₅H₄R¹)₂R²₂]^–, characterised by e.s.r. spectroscopy [g_av, 1·991 ± 0·007; a(¹H), 0·26 ± 0·09 mT; a(^47,49Ti), 0·87 ± 0·16 mT; a(⁹¹Zr), 2·06 ± 0·34 mT; a(¹⁷⁷Hf), not observed]; commercial samples of HfCl₄ contain 5–10% of the Zr analogue, as estimated by ¹³C n.m.r. (on an organometallic derivative) or e.s.r. spectroscopy of the derived d¹ dialkylmetallate(III).