Bis(indenyl)hafnium Chemistry: Ligand-Induced Haptotropic Rearrangement and Fundamental Reactivity Studies at a Reduced Hafnium Center
Doris Pun
Scott M. Leopold
Christopher A. Bradley
Emil Lobkovsky
Paul J. Chirik
10.1021/om900046e.s001
https://acs.figshare.com/articles/dataset/Bis_indenyl_hafnium_Chemistry_Ligand_Induced_Haptotropic_Rearrangement_and_Fundamental_Reactivity_Studies_at_a_Reduced_Hafnium_Center/2861500
The chemistry of reduced bis(indenyl)hafnium compounds has been explored. Sodium amalgam reduction of (η<sup>5</sup>-C<sub>9</sub>H<sub>5</sub>-1,3-(SiMe<sub>3</sub>)<sub>2</sub>)<sub>2</sub>HfCl<sub>2</sub> was studied in several different solvents. While reduction in toluene resulted in decomposition, performing the reaction in the presence of THF or 1,2-dimethoxyethane (DME) yielded η<sup>6</sup>,η<sup>5</sup>-bis(indenyl)hafnium solvent (THF or DME) complexes arising from ligand-induced haptotropic rearrangement. Using less coordinating solvents such as diethyl ether or 2,5-dimethyl THF furnished a rare example of a structurally characterized hafnocene(III) complex, (η<sup>5</sup>-C<sub>9</sub>H<sub>5</sub>-1,3-(SiMe<sub>3</sub>)<sub>2</sub>)<sub>2</sub>HfCl. An unusual sodium chloride complex of η<sup>6</sup>,η<sup>5</sup>-bis(indenyl)hafnium, [(η<sup>6</sup>-C<sub>9</sub>H<sub>5</sub>-1,3-(SiMe<sub>3</sub>)<sub>2</sub>)(η<sup>5</sup>-C<sub>9</sub>H<sub>5</sub>-1,3,-(SiMe<sub>3</sub>)<sub>2</sub>)HfCl]<sub>2</sub>Na[Na(DME)<sub>3</sub>], was also isolated and crystallographically characterized as a byproduct from synthesis of the DME compound. The reactivity of the η<sup>6</sup>,η<sup>5</sup>-bis(indenyl)hafnium THF compound as an isolable source of Hf(II) was also evaluated. Addition of H<sub>2</sub> or <i>N</i>,<i>N</i>-dimethylaminopyridine (DMAP) resulted in facile oxidative addition, while C−O cleavage of THF was observed upon mild heating. Preparation of the corresponding hafnocene dicarbonyl derivatives allowed comparison of the electronic properties of the new complexes as compared to their zirconocene congeners.
2009-04-27 00:00:00
zirconocene congeners
DMAP
THF
diethyl ether
Fundamental Reactivity Studies
Sodium amalgam reduction
solvent
bi
H 2
DME compound
9H
hafnocene dicarbonyl derivatives
Reduced Hafnium CenterThe chemistry
oxidative addition
sodium chloride
complex
isolable source