F. Geoffrey N. Cloke, John R. Hanks, Peter B. Hitchcock and John F. Nixon
The novel, fully structurally characterised, 14e-titanocene [Ti(η5-(P3C2But2)2] made by (i) cocondensation of titanium vapour with the phosphaalkyne ButCP (ii) reaction of ButCP with [Ti(η6-C6H5Me)2] at –78 °C or (iii) by heating TiCln with n(KP3C2But2) (n = 2, 3) in toluene at 110 °C, undergoes an unusual [2+2] cycloaddition reaction with ButCP to give [Ti(η5-P3C2But2)(η3-η2-P4C3But3)].