Our research in main group organometallic chemistry of Si, Ge, and Sn focused on the activation of organic molecules. A summary of our published work can be found here.
The group explored transition metal germylene chemistry. Germylene ligands bind strongly to transition metal complexes, similar to a phosphine, but retain a Lewis acidic site. This empty orbital can be used to create a formal double bond with a filled transition metal orbital or can simply provide a Lewis acid site in close proximity to a basic metal. The first new complex made by the group is shown below. This work was published in Organometallics 1995, 14, 5008-5010.
This Platinum-Germylene complex, containing both three-coordinate Pt and Ge, undergoes reversible reactions with dihydrogen and carbon dioxide as indicated below.
The metal germylenes form metallacycles with a number of substrates and undergo further insertion reactions to make interesting heteroatom rings. Much of this work is summarized in the scheme below. This work was published in JACS 1998, 120, 7484-7492 and Inorganic Chemistry 1998, 37, 6461-6469.
More recently, we have discovered that germylenes are capable of intermolecular C-H insertion reactions. Specifically, they react with the a-CH bonds of nitriles as shown in the scheme below (JACS 2001, 123, 982-983).
We have also made a very interesting discovery in the area of phenone activation. Germylenes can quantitatively and quickly convert the phenone functional group to a conjuated triene. We are working to exploit this reaction in the arena of organic synthesis. An ORTEP diagram from the X-ray crystal structure analysis of germylene bound to propiophenone is shown below. This work was published as a series of papers in Organometallics. (2002, 21, 457-459; 2003, 22, 4613-4615; 2003, 22, 3222-3229).
Additional work on CH-activation lead to the direct formation of Ge or Sn bonds and the subsequent use of these materials for synthetic applications.
Unfortunately after many failed attemps to get funds, this project has been placed on a hiatus.