Our research centers on the synthesis of chiral early transition metal complexes which are characterized by low electron counts and coordination spheres which lend a facial bias to incoming substrate ligands.
One project is focused on supersized pianostool complexes of zirconium, niobium and tantalum with the tetraphenylcyclopentadienyl, pentaphenylcyclopentadienyl ligand, C5Ph5 and m-tolyltetraphenylcyclopentadienyl, mt-Cp, Cp’MXn (M=Zr, X =NMe2, n = 3; M = Nb, Ta, X= Cl, n=4). Routes to these compounds involve preparation of new trialkyl silicon and tin cyclopentadienes. The complexes promote silylcyanation of aryl and alkyl aldehydes. Efforts to prepare chiral derivatives of these piano stool complexes are ongoing.
A second project is addressing the preparation of surface bound chiral metal complexes. Silica gel, properly dried, reacts cleanly to covalently bond trisdimethylamidozirconium(IV) via one Si-O-Zr linkage. The remaining amido ligands can be sequentially substituted with protic ligands such as binaphthol to form surface organometallic complexes that are active in silylcyanation and other Lewis acid catalyzed processes.Undergraduates interested in a research experience and MS candidates are encouraged to check out the work here. You will learn how to prepare, characterize and manipulate air-sensitive substances, using infrared and NMR (solution and solid state multinuclear and 2 dimensional methods) as well as characterization of catalyst efficacy.
Funding from the National Science Foundation is gratefully acknolwedged for support of this project.