Synthesis and Structure of Titanium(III) Bis(decamethyltitanocene) Oxide

Bis­(decamethyltitanocene)
oxide, [(Cp*2Ti)2O] (1; Cp* = η5-C5Me5) has been obtained as a yellow
crystalline solid after reacting
equimolar amounts of the hydride [Cp*2TiH] and the hydroxide
[Cp*2Ti­(OH)]. The solid-state structure of 1 revealed a linear Ti–O–Ti arrangement and a mutual,
nearly perpendicular orientation of the bent-sandwich titanocene moieties;
the length of both Ti–O bonds amounted to 1.9080(3) Å.
A unique structural feature was a close-to-eclipsed conformation of
the cyclopentadienyl ligands, attributed to the high steric congestion
of 1. The molecule in toluene glass exhibited a triplet
state EPR spectrum of rhombic symmetry, having zero field splitting D = 0.02159 cm–1 and E = 0.00230 cm–1. The 1H NMR spectrum
of 1 in toluene-d8 displays
a paramagnetic resonance at δ 4.3 ppm (Δν1/2 ≈ 270 Hz). Compound 1 reacts with 1 molar equiv
of water to give [Cp*2Ti­(OH)]. In CD2Cl2, 1 is oxidized to yield the major product [(Cp*TiCl2)2O] and minor product [{Cp*Ti­(Cl)­O}3].