Synthesis structure and reactivity of the hexaphospha-titanocene bis-( 5-35-di-i tert -butyl-124-triphosohacyclopentadieny) titanium(II)

The novel, fully structurally characterised, 14e-titanocene [Ti(¿5-(P3C2BU(t)2)2] made by (i) cocondensation of titanium vapour with the phosphaalkyne Bu(t)CP (ii) reaction of Bu(t)CP with [Ti(¿6-C6H5Me)2] at -78°C or (iii) by heating TiCl(n) with n(KP3C2Bu(t)2)(n = 2, 3) in toluene at 110°C, undergoes an unusual [2 + 2] cycloaddition reaction with Bu(t)CP to give [Ti(¿5-P3C2Bu(t)2)(¿3-¿2-P4C3Bu(t)3)].