Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 25, 2000 | Supplemental Material
Journal Article Open

Aminofluorenyl−Pentamethylcyclopentadienyl and Bis(aminofluorenyl) Derivatives of Group 4 Metals


New group 4 compounds containing a 9-(dialkylamino)fluorenyl ligand have been prepared, and their properties and reactivities have been briefly investigated. Single-crystal X-ray analysis of {9-(N,N-dimethylamino)fluorenyl}_2ZrCl_2 (4) reveals strong zirconium−nitrogen dative bonds. The asymmetric unit contains two molecules with an unusual coordination of aminofluorenyl ligands, best described as comprised of a strong Zr−N dative interaction and essentially an η^1-fluorenyl coordination, supplemented by a weak additional C C dative interaction of one double bond of one of the benzo units. The barrier to rotation around the C−N bond of {9-(N,N-diisopropylamino)fluorenyl}(pentamethylcyclopentadienyl)ZrCl_2 (9) has been determined:  ΔG⧧(−25 °C) = 11.1 kcal·mol^(-1). Unlike related aminoborollide complexes, aminofluorenyl complexes resist quaternization by alkyl halides. Several aminofluorenyl complexes have been tested for propylene polymerization behavior in the presence of methylaluminoxane (MAO); atactic polypropylene is obtained with very low activities. The syntheses of 9-(dialkylamino)fluorene compounds are described, as are the syntheses of group 4 compounds via the corresponding 9-(dialkylamino)fluorenide lithium salts.

Additional Information

© 2000 American Chemical Society. Received August 18, 2000. Publication Date (Web): November 16, 2000. This work has been funded by the USDOE Office of Basic Energy Sciences (Grant No. DE-FG03-88ER13431) and by a DOD National Defense Science and Engineering Fellowship awarded to S.M. The authors thank Dr. Michael Day and Mr. Lawrence Henling for obtaining the X-ray crystal structure.

Attached Files

Supplemental Material - om000723r_s.pdf


Files (328.8 kB)
Name Size Download all
328.8 kB Preview Download

Additional details

August 19, 2023
October 25, 2023