Synthesis of Low-Valent Titanium and Zirconium Metallocenes

In 1956, following the synthesis of ferrocene by Kealy and Pauson ( ), Fischer and Wilkinson (9) reported the isolation of a dark green, diamag- 

Crystals of 3 apparently proved to be unsuitable for X-ray structural work however, the molecular geometry of 3 as illustrated was confirmed 

The discovery in 1964 by Vol pin and Shur (47) of N2 reduction by (tj-CsH5)2TiCl2/RMgX mixtures (Section III,A) led several workers to postulate the intermediacy of (T -C5H5)2Ti in these dinitrogen fixation systems. 

The antisymmetric vTi H vibration for this compound is seen as an intense broad absorption at 1450 cm-1 (22). In contrast, treatment of a saturated hexane solution of (i7-C5H5)2Ti(CH3)2 (4) with H2 at 0°C gave a gray-green, presumably polymeric hydride, [(C5H5)2TiHl (6), having a characteristic vT1 H absorption at 1140 cm-1 (23,24). 

4) has shown that infrared spectra are not necessarily indicative of the presence of only (tj-C5H5), cyclopentadienyl ligands. We believe that 

---