Synthesis and Properties of Dicyclopentadienyltitanium(III) Neo-pentyl. Reactivity of Some Nitrogen-free Titanium(III) Compounds in Nitrogen Fixation

Reaction of Cp2TiCl with (CH3)3CCH2MgCl yields Cp2TiCH2(CH3)3; this compound reacts with N2 at —90° C to give the complex [Cp2TiCH2C(CH3)3]2N2 (ΔHf —12 kcal mol-1). In presence of sodium naphthalene (NaC10H8) or i-PrMgCl, Cp2TiCH2C(CH3)3 is active in reducing dinitrogen. The results obtained in the systems Cp2TiR/NaC10H8/THF/N2 with R = CH2C(CH3)3, CH2Si(CH3)3, m-CH3C6H4 and 2,6-(CH3)2C6H3 are reported, together with some reactions of Cp2TiCl2, Cp2TiCH2C(CH3)3 and Cp2TiCH2Si(CH3)3 with i-PrMgCl. The results indicate that in all these systems the same reduction mechanism is operative, viz. the mechanism described recently for the system (Cp2Tiaryl)2N2/NaC10H8/ THF/N2; removal of one of the Cp groups from the titanium atom is the first step in the reduction reaction