Nickel indenyl complexes

Pincer complexes

Polymerization reactions: 
- polyolefins
- polyalkynes
- polysilanes

Hydrosilylation reactions:
- alkenes
- ketones

Kinetic studies

X-ray crystallography

Synthesis, characterization, and reactivity studies of transition metal compounds constitute the central theme of our research. In some cases, target complexes are selected on the basis of their anticipated reactivities. For instance, some complexes are sought because of their anticipated aptitude to promote various catalytic reactions. In other cases, a class of compounds is targeted because that specific combination of metal and ligand(s) is rare or unknown, and might exhibit unusual chemical behavior. The following are examples of recent compounds prepared by our group.

Characterization and study of new compounds involve various spectroscopic methods such as multinuclear NMR, IR, X-ray diffraction, and gas chromatography/ mass spectrometry. The following are examples of structural characterizations carried out recently by X-ray diffraction studies.

(1-Me-indenyl)Ni(N,N-bis(mesityl)imidazol-2-ylidene)(Cl) 

The Zwitterion: [(1-Me-indenyl)Ni(Me₂PCH₂AlCH₂PMe₂)]

Current Projects

Catalysis:  Current projects include the development of new processes for a) the oligomerization of hydrosilanes to cyclic or linear polysilanes, b)  polymerization of alkynes and alkenes, c) C-N bond formation reactions such as coupling or hydroami-nation, d) the use of Lewis acidic cations in organic synthesis (e.g., hydrosilylation of alkenes and ketones). Another thrust is the design of new bifunctional, Lewis acid-Lewis base initiators for various catalytic reactions.

New metal-ligand combinations:  The ability of ligands to radically alter the chemical properties of transition metals makes them an important component of organometallic complexes.  Often the use of new ligand will lead to novel reactivities.  One interesting class of ligands is the multidentate ligands incorporating an indenyl ring and a tethered amine or phosphine.  These have been shown to form interesting new compounds whose reactivities are under study.  We are also studying the preparation of various multidentate and pincer-type ligands and their use in catalysis.

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Synthesis, Characterization, and Reactivities of New Complexes

Complexes of indenyl ligands featuring hemilabile moieties such as an amine are used as single-source pre-catalysts for olefin polymerization reactions...

...while systems with a hemilabile alkene moiety serve as both single-source pre-catalysts and models of the intermediates in the olefin polymerization reactions