The vinylidene structures in polypropylenes produced by ethylenebis(indenyl)zirconiumdichloride (En(Ind)(2)ZrCl2), 1, and isopropyl(cyclopentadienyl)(fluorenyl)zirconiumdichloride (iPr(Cp)(Flu)ZrCl2), 2, were analyzed by H-1 NMR. The vinylidene group adjacent to the chain end was clearly distinguished from other internal vinylidene structures for the first time using 1,2-dichlorobenzene as solvent. The polypropylene produced by 2 had much internal vinylidene groups compared with one by 1. (C) 2003 Published by Elsevier Ltd.