Structural studies of (π-C 5H 5) 2MX 2 complexes and their derivatives : The structure of 1,1′-trimethylenedicyclopentadienyl-dichlorozirconium

Abstract

1,1′Trimethylene-π-dicyclopentadienedichlorozirconium, (CH 2) 3(C 5H 4) 2- ZrCl 2, is orthorthombic, space group Pbca. The unit cell dimensions found were a = 8.277(2), b = 13.922(4), c = 22.568(5), Z = 8. The strucutre was determined from three-dimensional X-ray data (1049 independent reflection) refined to an R facotr of 2.64%. The coordination about the zirconium atom is that of the a distorted tetrahedron comprised of the chlorine atoms and the centroids of the π-cyclopentadienyl rings. The ClsZrCl bond angle is 96.92(7)° and the centroid Zrcentroid angle 129.5°. The ZrCl bond distances found are 2.451(2) and 2.431(2) Å which are very close to the sum of the Paulling radii. Zirconiumring centroid distances are 2.192 and 2.193 Å and the range of ZrC distances is 2.4772.516 Å. The carboncarbon distances within the π-cyclopentadiene rings verage 1.395(10) Å and range from 1.363(9) to 1.413(9) Å. These values establish the Pentahapto nature of the metalring bonding.