Rapid and efficient procedure for the synthesis of monocyclopentadienyl complexes of hafnium and zirconium

Bis(dimethyl sulfide) complexes of zirconium(IV) chloride and hafnium(IV) chloride have been found to undergo facile substitution reactions with 1-(trimethylsilyl)cyclopenta-2,4-diene and 1-(tri-n-butylstannyl)cyclopenta-2,4-diene, respectively, to afford the corresponding (η 5 -cyclopentadienyl)trichlorozirconium and -hafnium complexes