Preparation and characterization of monomeric and dimeric group IV metallocene dihydrides having alkyl-substituted cyclopentadienyl ligands
- California Inst. of Tech., Pasadena, CA (United States). Arnold and Mabel Beckman Labs. of Chemical Synthesis
A series of zirconocene dihydride complexes of the general form [(R{sub n}Cp){sub 2}ZrH{sub 2}]{sub x} having substituted cyclopentadienyl ligands has been prepared by hydrogenation of the corresponding dimethyl complexes. The most sterically crowded members (Cp{sup *}({eta}{sup 5}-C{sub 5}HMe{sub 4})ZrH{sub 2}, (Cp{sup *} = ({eta}{sup 5}-C{sub 5}Me{sub 5})), Cp{sup *}{l_brace}{eta}{sup 5}-C{sub 5}H{sub 3}-1,3-(CMe{sub 3}){sub 2}{r_brace}ZrH{sub 2} and {l_brace}{eta}{sup 5}-C{sub 5}H{sub 3}-1,3-(CMe{sub 3}){sub 2}{r_brace}{sub 2}ZrH{sub 2}) are monomeric; those less crowded members ([Cp{sup *}{l_brace}{eta}{sup 5}-C{sub 5}H{sub 4}(CMe{sub 3}){r_brace}ZrH{sub 2}]{sub 2}, [Cp{sup *}(THI)ZrH{sub 2}]{sub 2} (THI = {eta}{sup 5}-tetrahydroindenyl), and [{l_brace}{eta}{sup 5}-C{sub 5}H{sub 3}-1,3-(CHMe{sub 2}){sub 2}{r_brace}{sub 2}ZrH{sub 2}]{sub 2}) are predominantly dimeric in benzene solution. Cp{sup *}{l_brace}{eta}{sup 5}-C{sub 5}H{sub 3}-1,3-(CHMe{sub 2}){sub 2}{r_brace}ZrH{sub 2} and ({eta}{sup 5}-C{sub 5}HMe{sub 4}){sub 2}ZrH{sub 2} exist as equilibrium mixtures of monomer and dimer in benzene solution. The hydride ligands rapidly exchange with D{sub 2}, affording the dideuteride complexes. Deuterium incorporation into some of the substituents on the cyclopentadienyl rings of the monomeric dihydride complexes is also observed. The X-ray structures of Cp{sup *}{sub 2}HfH{sub 2}, Cp{sup *} {l_brace}{eta}{sup 5}-C{sub 5}H{sub 4}(CMe{sub 3}){r_brace}ZrCl{sub 2}, Cp{sup *}{l_brace}{eta}{sup 5}-C{sub 5}H{sub 3}-1,3-(CHMe{sub 2}){sub 2}{r_brace}ZrCl{sub 2} and {l_brace}{eta}{sup 5}H{sub 3}-1,3-(CMe{sub 3}){sub 2}{r_brace}{sub 2}ZrCl{sub 2} are reported.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG03-85ER13431
- OSTI ID:
- 354373
- Journal Information:
- Organometallics, Vol. 18, Issue 10; Other Information: PBD: 10 May 1999
- Country of Publication:
- United States
- Language:
- English
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